JP5772933B2 - Imaging device - Google Patents

Description

The present invention relates to an imaging apparatus .

  An automatic focus adjustment (AF) function that obtains the defocus amount of the photographing lens in a plurality of focus detection areas set in the photographing screen and adjusts the focus of the photographing lens based on the defocus amount of any area, and photographing The image of the subject to be tracked in the image is stored as a template image (reference image), and the subject to be tracked is tracked while searching for the position of an image that is the same as or similar to the template image among the repeatedly captured images. There is known an autofocus system that includes an image tracking function, selects a focus detection area corresponding to the position of the image tracking result, and adjusts the focus of the photographing lens based on the defocus amount of the focus detection area (see Patent Document 1). ).

JP-A-2005-2105040

  In the autofocus system disclosed in Patent Document 1, since the focus detection calculation of the photographing lens is performed based on the subject tracking calculation result, the focus detection calculation is started until the image information necessary for the subject tracking calculation is obtained. I can't. Therefore, for example, efficient control cannot be performed within the limited calculation processing time as in the case where the calculation processing time for individual shooting is limited, such as during continuous shooting.

An imaging apparatus according to a first aspect of the invention determines a defocus amount calculation unit that calculates a defocus amount, and determines the defocus amount of the focus detection area used for driving control of a focus optical system among a plurality of focus detection areas. A determination unit; a control unit that performs drive control of the focus optical system using the defocus amount determined by the determination unit; and the focus detection area used for drive control of the focus optical system by the control unit An acquisition unit that acquires first information related to a position, a tracking unit that acquires second information related to the position of the tracking target using reference information including information about the tracking target and image information repeatedly acquired by the imaging unit The defocus amount calculation unit includes at least one focus detection area selected using the first information before the calculation by the tracking unit is completed. A first defocus amount calculated Te, after calculation by the tracking unit is finished, a second defocus amount calculated for at least one of said focus detection areas is selected by using the second information, the determination unit Comparing at least one of the first defocus amount and the second defocus amount with a third defocus amount which is a defocus amount used for driving control of the focus optical system by the control unit. To determine the defocus amount used for driving control of the focus optical system .

An imaging apparatus according to a second aspect of the present invention is the imaging apparatus according to the first aspect, wherein the determining unit has a difference between the third defocus amount and the second defocus amount within a first predetermined value. The second defocus amount is determined as the defocus amount used for driving control of the focus optical system, and the difference between the third defocus amount and the second defocus amount is greater than the first predetermined value. When the difference between the third defocus amount and the first defocus amount is smaller than a second predetermined value, the first defocus amount is determined as the defocus amount used for driving control of the focus optical system. It is characterized by .

An imaging apparatus according to a third aspect of the present invention is the imaging apparatus according to the first or second aspect, wherein the defocus amount calculation unit is configured to perform a first shooting during continuous shooting and a post-first shooting. The first defocus amount and the second defocus amount are calculated during a period between the second shooting and the first defocus amount is calculated before the calculation by the tracking unit is completed. To do .

An imaging apparatus according to a fourth aspect of the present invention is the imaging apparatus according to the third aspect , wherein the defocus amount calculation unit is configured to perform the first imaging in a period between the first imaging and the second imaging. for the focus detection area obtained by calculating the defocus amount calculation of the defocus amount, characterized in that it does not calculating the defocus amount calculation of the second defocus amount.

An imaging apparatus according to a fifth aspect of the present invention is the imaging apparatus according to any one of the first to fourth aspects, wherein the imaging unit is a photometric sensor used for photometry.

  According to the present invention, efficient control can be performed within a limited calculation processing time.

It is a figure which shows the structure of the imaging device provided with the image tracking apparatus by one embodiment. It is a figure which shows the detailed structure of a body control apparatus. It is a figure showing the detailed composition of the 2nd image sensor. It is a figure which shows a mode that the pixel of the 2nd image sensor was divided | segmented. It is a figure which shows the example of a to-be-photographed image. It is a figure which shows a mode that a template image is acquired. It is a figure which shows a mode that a tracking area | region is specified within the image for tracking. It is a flowchart which shows the subject tracking process of one Embodiment. It is a flowchart which shows the employ | adopted defocus amount determination process performed by a subject tracking process. 10 is a flowchart illustrating adopted defocus amount determination processing following FIG. 9. It is a flowchart which shows the imaging | photography process performed by a subject tracking process. It is a flowchart which shows the selection area priority focus detection calculation process performed by an imaging | photography process. It is a flowchart which shows the latter half focus detection calculation process performed by an imaging | photography process.

  An image tracking device according to an embodiment of the present invention will be described below. The image tracking device of the present embodiment stores reference information related to a reference image, captures an image by an imaging optical system, and outputs image information. Then, with respect to an image corresponding to the reference information in the image corresponding to the image information, the position of the target image is recognized in the shooting screen and is tracked. At this time, before recognizing the position of the target image, the focus adjustment state of the imaging optical system is detected. After recognizing the position of the target image, the focus adjustment state of the imaging optical system is changed with respect to the position. It is intended to be detected.

  FIG. 1 shows a configuration of an imaging apparatus (single-lens reflex digital still camera) 1 including an image tracking apparatus according to an embodiment. In FIG. 1, illustration and description of camera devices and circuits not directly related to the present invention are omitted. In a camera 1 according to an embodiment, an interchangeable lens 3 is attached to a camera body 2 in a replaceable manner. The interchangeable lens 3 has a photographing lens 8 that is an imaging optical system. The photographing lens 8 includes a zooming lens 8a and a focusing lens 8b.

  The camera body 2 is provided with a first image sensor 4 for capturing a subject image and recording a captured image. The first image sensor 4 can be composed of, for example, a CCD or a CMOS. At the time of photographing, the quick return mirror 5 and the sub mirror 6 are retracted to a position outside the photographing optical path indicated by a solid line, the shutter 7 is opened, and a subject image is formed on the light receiving surface of the first image sensor 4 by the photographing lens 8.

At the bottom of the camera body 2, a focus detection optical system 9 and a distance measuring element 10 for detecting the focus adjustment state of the photographing lens 8 are provided. In this embodiment, an example is shown in which a focus detection method based on a pupil division type phase difference detection method is employed. The focus detection optical system 9 guides the pair of focus detection light fluxes that have passed through the photographing lens 8 to the light receiving surface of the distance measuring element 10 and forms a pair of optical images. The distance measuring element 10 includes, for example, a pair of CCD line sensors, and outputs a focus detection signal corresponding to the pair of optical images. Before shooting, the quick return mirror 5 and the sub mirror 6 are set at positions in the shooting optical path as indicated by broken lines, and the pair of focus detection light beams from the shooting lens 8 are transmitted through the half mirror portion of the quick return mirror 5. Then, the light is reflected by the sub mirror 6 and guided to the focus detection optical system 9 and the distance measuring element 10.

  A finder optical system is provided on the upper part of the camera body 2. Before shooting, the quick return mirror 5 and the sub mirror 6 are in positions indicated by broken lines, and subject light from the shooting lens 8 is reflected by the quick return mirror 5 and guided to the focusing screen 11, and the subject image is displayed on the focusing screen 11. Form an image. The liquid crystal display element 12 superimposes and displays information such as a focus detection area mark on the subject image formed on the focusing screen 11 and displays various photographing information such as an exposure value at a position outside the subject image. The subject image on the focusing screen 11 is guided to the eyepiece window 15 via the penta roof prism 13 and the eyepiece lens 14 so that the photographer can visually recognize the subject image.

  The finder optical system at the top of the camera body 2 is provided with a second image sensor 16 that captures a subject image for subject tracking and photometry. The subject image formed by the photographic lens 8 imaged on the focusing screen 11 before photographing is re-imaged on the light receiving surface of the second image sensor 16 via the penta roof prism 13, the prism 17 and the imaging lens 18. The second image sensor 16 captures the subject image and outputs image information. Although details will be described later, image tracking control and exposure control are performed based on image information output from the second image sensor 16.

  The camera body 2 is also provided with a body control device 19 and an operation member 20. The body control device 19 includes a microcomputer, which will be described in detail later, and peripheral components such as a memory and an A / D converter, and performs various controls and calculations of the camera 1. The operation member 20 includes a switch and a selector for operating the camera 1, such as a shutter button, a focus detection area selection switch, a shooting mode selection switch, and a focus adjustment mode selection switch.

  The interchangeable lens 3 is provided with a zooming lens 8a, a focusing lens 8b, a diaphragm 21, a lens control device 22, and the like. In this embodiment, the photographing lens 8 is represented by a zooming lens 8a and a focusing lens 8b. However, the configuration of the photographing lens 8 is not limited to the configuration shown in FIG. The lens control device 22 includes a microcomputer (not shown) and peripheral components such as a memory, a drive circuit, an actuator, and a sensor. The lens control device 22 controls the driving of the lenses 8a and 8b and the diaphragm 21 and detects their positions. And information such as the maximum aperture value are output.

  The body control device 19 and the lens control device 22 communicate via the contact 23 of the lens mount unit. Information such as a lens driving amount and a control aperture value is transmitted from the body control device 19 to the lens control device 22. On the other hand, information such as the focal length by the zooming lens 8a, the photographing distance by the focusing lens 8b, and the aperture value is transmitted from the lens control device 22 to the body control device 19. The monitor 24 is provided on the back surface of the camera body 2 and displays various shooting information in addition to the through image and the shot image.

FIG. 2 shows a detailed configuration of the body control device 19. Note that illustration and description of control functions not directly related to the present invention are omitted. The body control device 19 includes an element control circuit 19a, an A / D converter 19b, a microcomputer 19c, a memory 19d, and the like. The element control circuit 19 a controls charge accumulation and reading of the second image sensor 16. The A / D converter 19b converts an analog image signal output as image information from the second image sensor 16 into a digital image signal. The microcomputer 19c constitutes a tracking control unit 19e, an exposure control unit 19f, a focus detection calculation unit 19g, and a lens drive amount calculation unit 19h according to a software form. The memory 19d stores information on a template image (reference image) for image tracking as reference information regarding an image used as a reference at the time of image tracking.

  The tracking control unit 19e sets, as a template image, an image of a portion corresponding to a designated position among images represented by image information obtained by capturing a subject image with the second image sensor 16. The tracking target position setting method will be described in detail later. Information on this template image is stored in the memory 19d as reference information. Thereafter, the tracking control unit 19e further corresponds to the reference information in the image represented by the image information based on the image information output from the second image sensor 16 at predetermined time intervals and the reference information stored in the memory 19d. The position of the image portion, that is, the position of the image portion that matches or is similar to the template image is recognized and tracked. Such image tracking processing is repeatedly performed in the tracking control unit 19e.

  The exposure control unit 19f calculates an exposure value at the time of shooting based on the image information output from the second image sensor 16. The exposure value obtained by the exposure control unit 19f is output to the lens control device 22 and used for driving control of the diaphragm 21, and also used for controlling the shutter 7.

  The focus detection calculation unit 19g is based on a focus detection signal corresponding to the pair of optical images output from the distance measuring element 10, and uses a known phase difference detection method or the like to adjust the focus adjustment state of the photographic lens 8, here the defocus amount. Is detected. Although details will be described later, a plurality of focus detection areas (focus detection positions) are respectively set corresponding to a plurality of positions in the image plane of the photographing lens 8. The focus detection calculation unit 19g detects a defocus amount for each of the plurality of focus detection areas based on a focus detection signal corresponding to a pair of optical images output from the distance measuring element 10.

  In the camera 1 according to the embodiment, either one of two focus adjustment modes having different control methods can be set according to the user's operation under the control of the body control device 19. One mode is a tracking priority mode in which focus adjustment is performed with emphasis on the result of image tracking. When this mode is set, the defocus amount detected in the focus detection area corresponding to the position of the image corresponding to the reference image recognized by the image tracking is preferentially adopted, and the focus adjustment of the photographing lens 8 is performed. I do. Another mode that can be set in the camera 1 is a selection area priority mode in which focus adjustment is performed with emphasis on the focus detection area selected in advance by the user. When this mode is set, the defocus amount for the focus detection area selected in advance by the user is preferentially adopted and the focus adjustment is performed.

  The lens driving amount calculation unit 19 h converts the adopted defocus amount into a lens driving amount and outputs the lens driving amount to the lens control device 22. Based on this lens drive amount, the focusing lens 8b is driven by the lens control device 22, and the focus of the photographing lens 8 is adjusted.

  FIG. 3 is a front view showing a schematic configuration of the second image sensor 16. The second imaging element 16 includes a plurality of pixels (photoelectric conversion elements) 26 (here, 8 horizontal × 6 vertical = 48) arranged in a matrix. As shown in FIG. 4, each pixel 26 is divided into three portions 26a, 26b, and 26c, and primary color filters of red R, green G, and blue B are provided in these portions 26a, 26b, and 26c, respectively. . Thereby, the RGB signal of the subject image can be output for each pixel 26. Note that the number of pixels of the second image sensor 16 is not limited to the number of pixels in this embodiment.

Next, a subject tracking operation according to an embodiment will be described. 5 to 7 are diagrams for explaining a subject tracking method according to an embodiment, and FIGS. 8 to 13 are flowcharts illustrating subject tracking processing according to the embodiment. The quick return mirror 5 is set in the photographing optical path shown by the broken line in FIG. 1 except when the shutter button is fully pressed to shoot, and the subject light incident from the photographing lens 8 forms an image on the focusing screen 11. Is done. Then, the subject image on the focusing screen 11 is guided to the second image sensor 16 via the penta roof prism 13, the prism 17 and the imaging lens 18, and the image information of the subject image is output from the second image sensor 16.

  FIG. 5 is an example of a subject image (viewfinder image) visually recognized by the photographer through the eyepiece window 15. Shooting information such as a focus detection area mark is superimposed on the subject image formed on the focusing screen 11 by the photographing lens 8 by the liquid crystal display element 12, and is passed to the eyepiece window 15 via the penta roof prism 13 and the eyepiece 14. The photographer can visually recognize the subject image and the photographing information. In this embodiment, eleven focus detection areas 45 a to 45 k are set in the photographing screen of the photographing lens 8, and area marks are superimposed on the subject image on the focusing screen 11 by the liquid crystal display element 12. The positions of the focus detection areas 45a to 45k are displayed. When an arbitrary area is selected by the focus detection area selection switch of the operation member 20, the mark 45 of the area is lit up.

  When the shutter button of the operation member 20 is half-pressed, the body control device 19 starts the subject tracking process shown in FIG. In step S <b> 1, the body control device 19 acquires image information output from the second image sensor 16. In this image information, the RGB value for each pixel is expressed as shown in (1) below. In Expression (1), x and y represent pixel coordinate values. In the second image sensor 16 shown in the example of FIG. 3, x = 1 to 8 and y = 1 to 6.

R [x, y], G [x, y], B [x, y] (1)
In step S2, the body control device 19 calculates the color information (here, color deviation) RG and BG of each pixel based on the image information acquired in step S1, and the exposure time T when the image is acquired. Based on the gain Gain and the color synthesis coefficients Kr, Kg, Kb, the luminance information L is calculated by the following equation (2).

RG [x, y] = Log ₂ (R [x, y]) − Log ₂ (G [x, y]),
BG [x, y] = Log ₂ (B [x, y]) − Log ₂ (G [x, y]),
L [x, y] = Log ₂ (Kr × R [x, y] + Kg × G [x, y] + Kb × B [x, y]) − Log ₂ (T) −Log ₂ (Gain) (2)
The body control device 19 stores the color information RG, BG and luminance information L in the memory 19d for use as a template image.

  In step S <b> 3, the body control device 19 acquires a focus detection signal corresponding to the pair of optical images for focus detection detected for each of the focus detection areas 45 a to 45 k by the distance measuring element 10.

  In step S4, the body control device 19 determines the defocus amount D [N] (N = a) indicating the focus adjustment state of the photographing lens 8 in each of the focus detection areas 45a to 45k based on the focus detection signal acquired in step S3. ~ K). Note that the characters entering N represent the corresponding focus detection areas. That is, for example, the defocus amount obtained for the focus detection area 45a is represented as D [a]. In this way, the body controller 19 calculates the defocus amount, so that the focus adjustment state of the photographing lens 8 is detected.

In step S5, the body control device 19 sets a tracking target position to be subjected to image tracking. Here, for example, the user selects any one of the focus detection areas 45a to 45k, and the selected focus detection area is set as the tracking target position. Alternatively, the tracking target position may be automatically set by the camera 1. For example, a focus detection area indicating the closest defocus amount is automatically set as the tracking target position. Any focus detection area may be selected by a method other than this and set as the tracking target position.

  In step S6, the body control device 19 acquires reference information, that is, information on the template image for image tracking, and stores it in the memory 19d. Here, among the color information and luminance information calculated in step S2, the color information and luminance information of the image portion corresponding to the predetermined range around the tracking target position set in step S5 are stored as reference information in the memory 19d. To do.

For example, as shown in FIG. 6 (a), when the focus detection area 45f located at the center of the screen is set as the tracking target position, the dotted line area indicated by reference numeral 47 around it is set as the tracking subject area. The color information and luminance information of the part corresponding to the area are stored as reference information. That is, RG [x, y], BG [x, y] and L [x, y] represented by the above-mentioned formula (2) are set as reference information for the ranges of x = 4 to 5 and y = 3 to 4. Is stored in the memory 19d. Thereby, the template image information 48 shown in FIG. 6B is stored as the reference information. If the color information (in this case, the color deviation) of the template image 48 stored in this way is expressed as TRG and TBG, and the luminance information is expressed as TL, these are expressed as the following equation (3). Here, the template image information 48 for two vertical pixels and two horizontal pixels is stored as the reference information, but the size of the template image is not limited to this.

TRG [TX, TY] = RG [x, y],
TBG [TX, TY] = BG [x, y],
TL [TX, TY] = L [x, y] (TX, TY = 1 to 2, x = 4 to 5, y = 3 to 4)
(3)
In step S <b> 7, the body control device 19 acquires the image information output from the second image sensor 16 as in step S <b> 1. In the next step S8, the body control device 19 calculates the color information RG and BG and the luminance information L of each pixel based on the image information acquired in step S7, as in step S2.

  In step S9, the body control device 19 executes an image tracking calculation for recognizing the position of the tracking target image in the shooting screen based on the color information and luminance information calculated in step S8. Here, by comparing the color information and luminance information calculated in step S8 with the reference information stored in step S6, an image corresponding to the reference information is detected and its position is specified. The method will be described below.

When performing the image tracking calculation, first, the body control device 19 sequentially cuts out an area having the same size as the template image 48 from the image (tracking image) represented by the color information and the luminance information acquired in step S8. A color information difference Diff is calculated for each pixel corresponding to the cut-out image and the template image 48. For example, if a tracking image as shown in FIG. 7A is acquired, the color information of the template image 48 is shifted while shifting the area one pixel at a time in the tracking image, as shown by a thick broken line in the figure. The difference Diff is calculated.

  Now, as shown in FIG. 7A, assuming that the start point position of the cut out image is (HX, HY) = (3, 2), the calculation of the difference Diff is obtained by the following equation (4).

Diff [HX, HY] = ΣΣ {Krg × ABS (RG [HX-1 + TX, HY-1 + TY] −TRG [TX, TY]) + Kbg × ABS (BG [HX-1 + TX, HY-1 + TY] −TB
G [TX, TY]) + K1 × ABS (L [HX-1 + TX, HY-1 + TY] −TL [TX, T
Y])} (4)
In the above equation (4), Krg, Kbg, and Kl are weighting coefficients that are set in advance in consideration of the difference in the degree of influence between each color information and luminance information. Also, TX, TY = 1 to 2, HX = 3
, HY = 2, and ΣΣ is the sum operation of TX = 1-2 and TY = 1-2.

  Next, the body control device 19 searches for the minimum difference in the difference Diff [HX, HY], and specifies the cut-out area when the minimum difference is calculated in the tracking image as the tracking area. Here, for example, as shown in FIG. 7B, the cut-out area indicated by reference numeral 49 whose start point position is (x, y) = (6, 3) is set as the tracking area. Thus, by specifying the tracking region 49 in the tracking image, the position of the image corresponding to the template image 48 in the tracking image is recognized.

Here, a process of updating the image information of the template image 48 using the image information of the specified tracking area 49 may be added. In this case, for example, by adding 20% of the image information of the tracking area 49 to the image information 80% of the original template image 48, the latest image information is updated little by little with respect to the information of the template image. It becomes easier to follow changes. In this case, the update may not be performed every time the tracking calculation is performed, but may be updated only when the position difference Diff determined as the tracking area 49 is smaller than a certain threshold value. Further, an image feature amount indicating a difference from the template image 48 may be obtained by a method other than the expression (4).

  In step S10, the body control device 19 acquires a focus detection signal corresponding to the pair of optical images for focus detection detected by the distance measuring element 10 for each of the focus detection areas 45a to 45k. In step S11, the body control device 19 determines the defocus amount D [N] (N = a) indicating the focus adjustment state of the photographing lens 8 in each of the focus detection areas 45a to 45k based on the focus detection signal acquired in step S10. ~ K).

  In step S12, the body control device 19 executes an adopted defocus amount determination process for determining which of the defocus amounts calculated in step S11 is to be used for focus adjustment. Details of the adopted defocus amount determination process will be described later with reference to the flowcharts of FIGS. By executing the adopted defocus amount determination process in step S12, the body control device 19 determines one of the defocus amounts calculated in step S11 as the adopted defocus amount used for the current focus adjustment.

  In step S <b> 13, the body control device 19 converts the adopted defocus amount determined in step S <b> 12 into a lens drive amount, and drives the focusing lens 8 b by the lens control device 22 to adjust the focus of the photographing lens 8. .

  In step S <b> 14, the body control device 19 confirms whether or not the user has fully pressed the shutter button of the operation member 20. When the shutter button is fully pressed, the process proceeds to step S15, and the photographing process is executed in step S15. The detailed contents of this photographing process will be described later with reference to the flowcharts of FIGS. After executing step S15, the body control device 19 ends the flowchart of FIG. 8 and completes the subject tracking process.

  On the other hand, if the shutter button has not been fully pressed in step S14, the body control device 19 proceeds to step S16 and confirms whether or not the shutter button has been pressed halfway. If the half-press operation of the shutter button is continued, the process returns to step S7 and the above-described processing is repeated. On the other hand, if the shutter button is not half-pressed, the flowchart of FIG. 8 is terminated and the subject tracking process is completed.

Next, the adopted defocus amount determination process executed in step S12 will be described. 9 and 10 are flowcharts of the adopted defocus amount determination process. In step S21, the body control device 19 determines whether the set mode is the selection area priority mode or the tracking priority mode described above. If the selection area priority mode is set, the process proceeds to step S22. If the tracking priority mode is set, the process proceeds to step S31 in FIG.

  In step S22, the body control device 19 sets the defocus amount of the focus detection area (user selection area) selected in advance by the user among the defocus amounts calculated for the focus detection areas 45a to 45k in step S11 of FIG. get. For example, in FIG. 7B, when the focus detection area 45f is set as the user selection area, the defocus amount D [f] of the focus detection area 45f is acquired.

  In step S23, the body control device 19 compares the defocus amount of the user selection area acquired in step S22 with the adopted defocus amount determined in step S12 executed last time. That is, in the above example, the defocus amount D [f] acquired as the defocus amount of the user selection area is compared with the previous adopted defocus amount. When the adopted defocus amount determination process of step S12 is first executed after the shutter button is half-pressed, the defocus amount of the focus detection area set as the tracking target position in step S5 is set to the previous adopted defocus amount. The focus amount may be used.

  In step S24, the body control device 19 determines whether or not the difference between the defocus amount of the user selection area compared in step S23 and the previous adopted defocus amount is within a predetermined value. When the difference between these defocus amounts is within a predetermined value, the process proceeds to step S25, and in step S25, the defocus amount of the user selection area acquired in step S22 is adopted and determined as the currently adopted defocus amount. That is, in the above example, the defocus amount D [f] is set as the currently adopted defocus amount. After executing step S25, the body control device 19 ends the adopted defocus amount determination process and proceeds to step S13 in FIG. On the other hand, if the difference between the defocus amount of the user selection area compared in step S23 and the previous adopted defocus amount is greater than or equal to a predetermined value, the process proceeds to step S26.

  In step S26, the body control device 19 defocuses the focus detection area in the peripheral area of the user selection area, that is, in the periphery of the user selection area, among the defocus amounts calculated for the focus detection areas 45a to 45k in step S11. Get the quantity. For example, as described above, when the focus detection area 45f is set as the user selection area in FIG. 7B, the defocus amounts D of the focus detection areas 45b, 45e, 45g, and 45j adjacent to the upper, lower, left, and right sides thereof. [b], D [e], D [g] and D [j] are obtained.

  In step S27, the body control device 19 selects a defocus amount having the smallest difference from the previous adopted defocus amount among the defocus amounts in the peripheral area of the user selection area acquired in step S26. For example, in the above example, among the acquired defocus amounts D [b], D [e], D [g], and D [j], the difference between the defocus amount D [g] and the previously adopted defocus amount is Is the smallest, the defocus amount D [g] is selected.

  In step S28, the body control device 19 determines whether or not the difference between the defocus amount selected in step S27 and the previous adopted defocus amount is within a predetermined value. If the difference between these defocus amounts is within a predetermined value, the process proceeds to step S29, and in step S29, the defocus amount selected in step S27 is adopted and determined as the current adopted defocus amount. That is, in the above example, the defocus amount D [g] is the current adopted defocus amount. After executing step S29, the body control device 19 ends the adopted defocus amount determination process and proceeds to step S13 in FIG.

  On the other hand, if the difference between the defocus amount selected in step S27 and the previous adopted defocus amount is greater than or equal to a predetermined value, the body control device 19 proceeds to step S30. In step S30, the body control device 19 determines that no effective defocus amount has been detected this time, and does not determine any of the defocus amounts calculated in step S11 as the adopted defocus amount. And After executing step S30, the body control device 19 ends the adopted defocus amount determination process and proceeds to step S13 in FIG. In this case, the driving control of the focusing lens 8b is not performed in the focus adjustment control in step S13, and therefore the focus adjustment state of the photographing lens 8 does not change.

  When it is determined in step S21 that the tracking priority mode is set and the process proceeds to step S31 in FIG. 10, in step S31, the body control device 19 calculates the defocus calculated for each focus detection area 45a to 45k in step S11. Of the amount, the defocus amount of the center area in the tracking region specified by the image tracking calculation in step S9 is acquired. Here, the focus detection area closest to the center of the tracking area is set as the central area, and the defocus amount is acquired. That is, in the example of FIG. 7B, the defocus amount D [g] of the focus detection area 45g located closest to the center of the tracking area 49 is acquired.

  In step S32, the body control device 19 compares the defocus amount of the central area in the tracking area acquired in step S31 with the adopted defocus amount determined in step S12 executed last time. That is, in the above example, the defocus amount D [g] is compared with the previous adopted defocus amount.

  In step S33, the body control device 19 determines whether or not the difference between the defocus amount of the central area in the tracking area compared in step S32 and the previous adopted defocus amount is within a predetermined value. If these differences are within a predetermined value, the process proceeds to step S34, and in step S34, the defocus amount of the central area in the tracking area acquired in step S31 is adopted as the current adopted defocus amount. That is, in the above example, the defocus amount D [g] is the current adopted defocus amount. After executing step S34, the body control device 19 ends the adopted defocus amount determination process and proceeds to step S13 in FIG. On the other hand, if the difference between the defocus amount of the central area in the tracking area compared in step S32 and the previous adopted defocus amount is equal to or larger than the predetermined value, the process proceeds to step S35.

  In step S35, the body control device 19 detects the focus located in and around the tracking area specified by the image tracking calculation in step S9, out of the defocus amounts calculated for the focus detection areas 45a to 45k in step S11. Get the defocus amount of the area. For example, the defocus amounts D [c], D [h], and D [k] of the focus detection areas 45c, 45h, and 45k adjacent to the tracking region 49 in FIG. At this time, the defocus amount of the central area in the tracking area acquired in step S31, that is, the defocus amount D [g] of the focus detection area 45g is excluded from acquisition targets.

  In step S36, the body control device 19 selects a defocus amount having the smallest difference from the previously adopted defocus amount among the defocus amounts acquired in step S35. For example, in the above example, when the difference between the acquired defocus amount D [c], D [h], and D [k] is the smallest difference between the defocus amount D [k] and the previous adopted defocus amount. Selects the defocus amount D [k].

In step S37, the body control device 19 determines whether or not the difference between the defocus amount selected in step S36 and the previous adopted defocus amount is within a predetermined value. If the difference is within the predetermined value, the process proceeds to step S38, and in step S38, the defocus amount selected in step S36 is adopted to determine the currently adopted defocus amount. That is, in the above example, the defocus amount D [k] is the current adopted defocus amount. After executing step S38, the body control device 19 ends the adopted defocus amount determination process and proceeds to step S13 in FIG. On the other hand, if the difference between the defocus amount selected in step S36 and the previous adopted defocus amount is greater than or equal to a predetermined value, the process proceeds to step S39.

  In step S39, the body control device 19 detects this time for the previous adoption area, that is, the focus detection area in which the previous adoption defocus amount is detected, among the defocus amounts calculated for the focus detection areas 45a to 45k in step S11. The obtained defocus amount and the defocus amount of the focus detection area located in the vicinity thereof are acquired. For example, if the previous adoption area is the focus detection area 45a in FIG. 7B, the defocus amount D [a] and the focus detection areas 45b, 45d, 45e, and 45f adjacent to the focus detection area 45a. Each defocus amount D [b], D [d], D [e] and D [f] is acquired.

In step S40, the body control device 19 selects a defocus amount having the smallest difference from the previously adopted defocus amount among the defocus amounts acquired in step S39. For example, in the above example, the acquired defocus amounts D [b], D [d], D [e], and D [
If the difference between the defocus amount D [f] and the previously adopted defocus amount is the smallest among the f], the defocus amount D [f] is selected.

  In step S41, the body control device 19 determines whether or not the difference between the defocus amount selected in step S40 and the previous adopted defocus amount is within a predetermined value. If these differences are within a predetermined value, the process proceeds to step S42, and in step S42, the defocus amount selected in step S40 is adopted and determined as the current adopted defocus amount. That is, in the above example, the defocus amount D [f] is set as the currently adopted defocus amount. After executing step S42, the body control device 19 ends the adopted defocus amount determination process and proceeds to step S13 in FIG.

  On the other hand, if the difference between the defocus amount selected in step S40 and the previous adopted defocus amount is greater than or equal to a predetermined value, the body control device 19 proceeds to step S43. In step S43, the body control device 19 determines that no effective defocus amount has been detected this time, and does not determine any of the defocus amounts calculated in step S11 as the adopted defocus amount. And After executing step S43, the body control device 19 ends the adopted defocus amount determination process and proceeds to step S13 in FIG. In this case, the driving control of the focusing lens 8b is not performed in the focus adjustment control in step S13, and therefore the focus adjustment state of the photographing lens 8 does not change.

  The adopted defocus amount determination process as described above is executed in step S12 of FIG. 8, and any one of the defocus amounts calculated in step S11 is determined as the adopted defocus amount used for the current focus adjustment. . Based on this adopted defocus amount, focus adjustment control is performed in step S13, so that the focus adjustment state of the taking lens 8 is appropriately changed according to the movement of the subject.

  Next, the photographing process executed in step S15 will be described. FIG. 11 is a flowchart of the photographing process. In step S51, the body control device 19 determines whether continuous shooting is in progress. If a predetermined continuous shooting operation, for example, the continuous shooting mode is set in the camera 1 and the shutter button is fully pressed, it is determined that continuous shooting is being performed, and the process proceeds to step S55. On the other hand, when such a continuous shooting operation is not performed, it is determined that continuous shooting is not being performed, and the process proceeds to step S52.

In step S52, the body control device 19 starts mirror up for retracting the quick return mirror 5 and the sub mirror 6 from the photographing optical path. When the mirror up is completed, the next step S53 is executed. In step S <b> 53, the body control device 19 acquires the captured image data by opening the shutter 7 and capturing the subject image formed by the photographing lens 8 with the first image sensor 4. The captured image data is recorded on an image recording medium (not shown) such as a memory card after necessary image processing. In step S54, mirror down for returning the quick return mirror 5 and the sub mirror 6 retracted from the photographing optical path to the photographing optical path is started. After executing step S54, the body control device 19 ends the photographing process.

  On the other hand, if it is determined in step S51 that continuous shooting is in progress and the process proceeds to step S55, in step S55, the body control device 19 determines whether the set mode is the selection area priority mode or the tracking priority mode described above. Determine if there is. When the selection area priority mode is set, the process proceeds to step S56, and when the tracking priority mode is set, the process proceeds to step S65.

  In step S <b> 56, the body control device 19 performs exposure control for the distance measuring element 10 and the second imaging element 16. In this exposure control, appropriate exposure times are set for the distance measuring element 10 and the second imaging element 16, respectively. When the set exposure time elapses, a focus detection signal is output from the distance measuring element 10 and image information is output from the second imaging element 16. After the exposure time set in the exposure control in step S56 has elapsed, in step S57, the body control device 19 starts mirror up for retracting the quick return mirror 5 and the sub mirror 6 from the photographing optical path.

  In step S58 after the start of mirror up, the body control device 19 detects the defocus amount with priority on the user selection area, and executes a selection area priority focus detection calculation process for adjusting the focus of the photographing lens 8. Details of the selection area priority focus detection calculation processing will be described later with reference to the flowchart of FIG. By executing the selection area priority focus detection calculation process in step S58, the body control device 19 obtains the defocus amount for any focus detection area and determines the adopted defocus amount used for the current focus adjustment.

  In step S59, the body control device 19 converts the adopted defocus amount determined in step S58 into a lens drive amount, and the lens control device 22 drives the focusing lens 8b to adjust the focus of the photographing lens 8. . Note that the selection area priority focus detection calculation processing in step S58 and the focus adjustment control in step S59 may be performed during mirror up.

  When the mirror up is completed, the body control device 19 executes Step S60. In step S <b> 60, the body control device 19 opens the shutter 7 and images the subject image formed by the photographing lens 8 with the first image sensor 4, and acquires photographed image data. Thereafter, the acquired photographed image data is recorded on the image recording medium as described above. In step S61, mirror down for returning the quick return mirror 5 and the sub mirror 6 retracted from the photographing optical path to the photographing optical path is started.

In steps S62 to S64, the body control device 19 performs processes similar to those in steps S7 to S9 in FIG. That is, in step S62, image information output from the second image sensor 16 is acquired, and in the next step S63, the color information RG, BG and luminance information L of each pixel are obtained based on the image information acquired in step S62. In the subsequent step S64, an image tracking calculation is executed based on the color information and luminance information calculated in step S63. Thereby, an image corresponding to the reference information in the image for tracking corresponding to the acquired image information,
That is, the position of the image corresponding to the template image 48 is recognized.

  If step S64 is performed, the body control apparatus 19 will return to step S51 and repeat the above processes. Thereby, when the selection area priority mode is set, the processing of steps S56 to S64 is repeated during continuous shooting. As a result, step S60 is repeatedly executed, and imaging by the first image sensor 4 is repeatedly performed a plurality of times.

  When it is determined in step S55 that the tracking priority mode is set and the process proceeds to step S65, in step S65, the body control device 19 performs exposure control on the distance measuring element 10 and the second image sensor 16 in the same manner as in step S56. Do. After the set exposure time has elapsed, in step S66, the body control device 19 starts mirror up for retracting the quick return mirror 5 and the sub mirror 6 from the photographing optical path.

  In step S67 after the start of mirror up, the body control device 19 executes a first half focus detection calculation process. In the first half focus detection calculation, the previous adoption area, that is, the focus detection area that detects the adopted defocus amount determined in the second half focus detection calculation process of step S71 executed last time, and the focus detection area located in the vicinity thereof. The defocus amount is calculated based on the focus detection signal from the distance measuring element 10. For example, if the previous adoption area is the focus detection area 45a in FIG. 7B, the current defocus amount D [a] in the focus detection area 45a and the focus detection area 45b adjacent to the focus detection area 45a. , 45d, 45e and 45f, the current defocus amounts D [b], D [d], D [e] and D [f] are obtained. Thus, before performing the image tracking calculation in step S70, the focus adjustment of the photographing lens 8 with respect to the focus detection area preliminarily selected as the previous adopted area and its peripheral area among the plurality of focus detection areas 45a to 45k. A state is required. Note that if the exposure time of the distance measuring element 10 has passed before the second image sensor 16, step S67 may be executed before the start of mirror up in step S66.

  In steps S68 to S70, the body control device 19 performs the same processes as steps S7 to S9 in FIG. 8 as in steps S62 to S64. That is, in step S68, image information output from the second image sensor 16 is acquired, and in the next step S69, the color information RG, BG and luminance information L of each pixel are obtained based on the image information acquired in step S68. In the subsequent step S70, an image tracking calculation is executed based on the color information and luminance information calculated in step S69. Thereby, the position of the image corresponding to the reference information in the tracking image corresponding to the acquired image information, that is, the position of the image corresponding to the template image 48 is recognized.

  In step S71, the body control device 19 detects the defocus amount with respect to the position of the image corresponding to the reference information recognized by the image tracking calculation in step S70, and the latter half focus for adjusting the focus of the photographing lens 8. Execute detection calculation processing. Details of the latter half focus detection calculation processing will be described later with reference to the flowchart of FIG. By executing the latter half focus detection calculation processing in step S71, the body control device 19 obtains the defocus amount for any focus detection area, and determines the adopted defocus amount used for the current focus adjustment.

  In step S72, the body control device 19 converts the adopted defocus amount determined in step S71 into a lens drive amount, and the lens control device 22 drives the focusing lens 8b to adjust the focus of the photographing lens 8. . Note that each of the processes in steps S67 to S72 may be performed during mirror up.

When the mirror up is completed, the body control device 19 executes Step S73. In step S <b> 73, the body control device 19 opens the shutter 7 and images the subject image formed by the photographing lens 8 with the first image sensor 4, and acquires photographed image data. Thereafter, the acquired photographed image data is recorded on the image recording medium as described above. In step S74, mirror down for returning the quick return mirror 5 and the sub mirror 6 retracted from the photographing optical path to the photographing optical path is started.

  If step S74 is performed, the body control apparatus 19 will return to step S51, and will repeat the above processes. Thereby, when the tracking priority mode is set, the processes of steps S65 to S74 are repeated during continuous shooting. As a result, step S73 is repeatedly executed, and imaging by the first image sensor 4 is repeatedly performed a plurality of times. The first half focus detection calculation process in step S67 and the second half focus detection calculation process in step S71 are performed at intervals of the plurality of times of imaging.

  In addition, you may make it perform said step S65-S74 when the imaging | photography time by the 1st image pick-up element 4 is longer than predetermined time. That is, when the exposure time is longer than the predetermined time due to dark subject brightness or the accumulation time of the first image sensor 4 is longer than the predetermined accumulation time, as shown in step S70. Before the image tracking calculation, the first half focus detection calculation process as shown in step S67 is performed, and after the image tracking calculation, the second half focus detection calculation process as shown in step S71 is performed. On the other hand, when the exposure time is shorter than the predetermined time or when the accumulation time is shorter than the predetermined accumulation time, the focus detection calculation process may be performed after performing the image tracking calculation.

  Thus, even when it takes time to obtain an image for tracking, similarly, the focus detection calculation process can be performed efficiently.

  Here, the selection area priority focus detection calculation process executed in step S58 will be described. FIG. 12 is a flowchart of the selection area priority focus detection calculation process. In step S81, the body control device 19 acquires a focus detection signal from the distance measuring element 10 for a user selection area that is a focus detection area selected in advance by the user from among the focus detection areas 45a to 45k, and the defocus amount. Is calculated. For example, in FIG. 7B, when the focus detection area 45f is set as the user selection area as described above, a focus detection signal is acquired for the focus detection area 45f, and the defocus amount D [f] is calculated. To do.

  In step S82, the body control device 19 compares the defocus amount of the user selection area calculated in step S81 with the adopted defocus amount determined in the previous selection area priority focus detection calculation process. That is, in the above example, the defocus amount D [f] calculated as the defocus amount of the user selection area is compared with the previous adopted defocus amount. When the selection area priority focus detection calculation process is executed for the first time, the last adopted defocus amount determined in step S12 in FIG. 8 may be used as the previous adopted defocus amount.

  In step S83, the body control device 19 determines whether or not the difference between the defocus amount of the user selection area compared in step S82 and the previous adopted defocus amount is within a predetermined value. When the difference between these defocus amounts is within the predetermined value, the process proceeds to step S84, and in step S84, the defocus amount of the user selection area calculated in step S81 is adopted and determined as the current adopted defocus amount. That is, in the above example, the defocus amount D [f] is set as the currently adopted defocus amount. After executing step S84, the body control device 19 ends the selected area priority focus detection calculation process and proceeds to step S59 in FIG. On the other hand, if the difference between the defocus amount of the user selection area compared in step S82 and the previous adopted defocus amount is greater than or equal to a predetermined value, the process proceeds to step S85.

  In step S85, the body control device 19 acquires a focus detection signal from the distance measuring element 10 for the peripheral area of the user selection area, that is, the focus detection area in the vicinity of the user selection area among the focus detection areas 45a to 45k. To calculate the defocus amount. For example, as described above, when the focus detection area 45f is set as the user selection area in FIG. 7B, focus detection signals are acquired for the focus detection areas 45b, 45e, 45g, and 45j adjacent to the upper, lower, left, and right sides. Then, defocus amounts D [b], D [e], D [g], and D [j] are calculated.

  In step S86, the body control device 19 selects a defocus amount having the smallest difference from the previous adopted defocus amount among the defocus amounts in the peripheral area of the user selection area calculated in step S85. For example, in the above example, of the calculated defocus amounts D [b], D [e], D [g], and D [j], the defocus amount D [g] is the difference from the previous adopted defocus amount. Is the smallest, the defocus amount D [g] is selected.

  In step S87, the body control device 19 determines whether or not the difference between the defocus amount selected in step S86 and the previous adopted defocus amount is within a predetermined value. When the difference between these defocus amounts is within a predetermined value, the process proceeds to step S88, and in step S88, the defocus amount selected in step S86 is adopted and determined as the current adopted defocus amount. That is, in the above example, the defocus amount D [g] is the current adopted defocus amount. After executing step S88, the body control device 19 ends the selected area priority focus detection calculation process and proceeds to step S59 in FIG. On the other hand, if the difference between the defocus amount selected in step S86 and the previous adopted defocus amount is greater than or equal to a predetermined value, the process proceeds to step S89.

  In step S89, the body control device 19 uses the ranging element for the focus detection areas located in and around the tracking area specified by the image tracking calculation executed in the previous step S64 among the focus detection areas 45a to 45k. The focus detection signal from 10 is acquired and the defocus amount is calculated. For example, the defocus amounts D [c], D [h], and D [k] of the adjacent focus detection areas 45c, 45h, and 45k are calculated for the tracking region 49 in FIG. 7B. Note that the defocus amount D [g] of the focus detection area 45g has already been calculated in step S85, and is excluded from the calculation target here.

  In step S90, the body control device 19 selects a defocus amount having the smallest difference from the previously adopted defocus amount among the defocus amounts calculated in step S89. For example, in the above example, when the defocus amount D [k] is the smallest difference from the previous adopted defocus amount among the calculated defocus amounts D [c], D [h], and D [k]. Selects the defocus amount D [k].

  In step S91, the body control device 19 determines whether or not the difference between the defocus amount selected in step S90 and the previous adopted defocus amount is within a predetermined value. If the difference is within the predetermined value, the process proceeds to step S92, and in step S92, the defocus amount selected in step S90 is adopted and determined as the current adopted defocus amount. That is, in the above example, the defocus amount D [k] is the current adopted defocus amount. After executing step S92, the body control device 19 ends the selected area priority focus detection calculation process and proceeds to step S59 in FIG.

On the other hand, if the difference between the defocus amount selected in step S90 and the previous adopted defocus amount is greater than or equal to a predetermined value, the body control device 19 proceeds to step S93. In step S93, the body control device 19 determines that no effective defocus amount has been detected this time, and does not determine any of the calculated defocus amounts as the adopted defocus amount, and does not adopt the defocus amount. After executing Step S93, the body control device 19 ends the selected area priority focus detection calculation process and proceeds to Step S59 in FIG. In this case, drive control of the focusing lens 8b is not performed in the focus adjustment control in step S59, and therefore the focus adjustment state of the photographing lens 8 does not change.

  By executing the selection area priority focus detection calculation process as described above in step S58 of FIG. 11, the defocus amount is detected giving priority to the user selection area, and the adopted defocus amount used for the current focus adjustment is determined. It is determined. Based on this adopted defocus amount, focus adjustment control is performed in step S59, so that the focus adjustment state of the photographing lens 8 is appropriately changed during continuous shooting according to the movement of the subject.

  Subsequently, the latter half focus detection calculation process executed in step S71 of FIG. 11 will be described. FIG. 13 is a flowchart of the latter half focus detection calculation process. In step S101, the body control device 19 determines whether or not the tracking area has been specified in the current image tracking calculation executed in the immediately preceding step S70. If the tracking area can be specified, that is, if the position of the reference information representing the template image 48 in the tracking image can be recognized, the process proceeds to step S102. On the other hand, when the tracking area cannot be specified, that is, when the position of the reference information representing the template image 48 in the tracking image cannot be recognized, the body control device 19 ends the second half focus detection calculation process and is shown in FIG. Proceed to step S72. As a result, when the tracking area cannot be specified, the body control device 19 prohibits the detection of the focus adjustment state of the photographing lens 8 by executing the latter half focus detection calculation process.

  In step S102, the body control device 19 detects the defocus amount of the center area in the tracking area identified by the image tracking calculation in step S70 among the focus detection areas 45a to 45k, that is, the focus detection closest to the center of the tracking area. For the area, the focus detection signal from the distance measuring element 10 is acquired and the defocus amount is calculated. That is, in the example of FIG. 7B, a focus detection signal is acquired for the focus detection area 45g located closest to the center of the tracking area 49, and the defocus amount D [g] is calculated.

  In step S103, the body control device 19 compares the defocus amount of the central area in the tracking area calculated in step S102 with the adopted defocus amount determined in the last-half focus detection calculation process executed last time. That is, in the above example, the calculated defocus amount D [g] is compared with the previous adopted defocus amount. When the second half focus detection calculation process is first executed, the last adopted defocus amount determined in step S12 in FIG. 8 may be used as the previous adopted defocus amount.

  In step S104, the body control device 19 determines whether or not the difference between the defocus amount of the central area in the tracking area compared in step S103 and the previous adopted defocus amount is within a predetermined value. When the difference between these defocus amounts is within the predetermined value, the process proceeds to step S105, and in step S105, the defocus amount of the central area in the tracking area calculated in step S102 is adopted to obtain the currently adopted defocus amount. decide. That is, in the above example, the defocus amount D [g] is the current adopted defocus amount. After executing Step S105, the body control device 19 ends the second half focus detection calculation process and proceeds to Step S72 in FIG. On the other hand, if the difference between the defocus amount of the central area in the tracking area compared in step S103 and the previously adopted defocus amount is equal to or larger than the predetermined value, the process proceeds to step S106.

In step S106, the body control device 19 focuses on the focus detection areas 45a to 45k from the distance measuring element 10 for the focus detection areas located in and around the tracking area specified by the image tracking calculation in step S70. A detection signal is acquired and a defocus amount is calculated. For example, with respect to the tracking region 49 in FIG. 7B, the focus detection signals from the distance measuring element 10 are acquired for the adjacent focus detection areas 45c, 45h, and 45k, and the defocus amounts D [c], D [h] and D [k] are calculated. Since the defocus amount D [g] of the focus detection area 45g closest to the center of the tracking area has already been calculated in step S102, it is excluded from the calculation target here.

  In step S107, the body control device 19 selects a defocus amount having the smallest difference from the previous adopted defocus amount among the defocus amounts calculated in step S106. For example, in the above example, when the defocus amount D [k] is the smallest difference from the previous adopted defocus amount among the calculated defocus amounts D [c], D [h], and D [k]. Selects the defocus amount D [k].

  In step S108, the body control device 19 determines whether or not the difference between the defocus amount selected in step S107 and the previous adopted defocus amount is within a predetermined value. When the difference between these defocus amounts is within the predetermined value, the process proceeds to step S109, and in step S109, the defocus amount selected in step S107 is adopted and determined as the currently adopted defocus amount. That is, in the above example, the defocus amount D [k] is the current adopted defocus amount. After executing Step S109, the body control device 19 ends the second half focus detection calculation process and proceeds to Step S72 in FIG. On the other hand, if the difference between the defocus amount selected in step S107 and the previous adopted defocus amount is greater than or equal to a predetermined value, the process proceeds to step S110.

  In step S110, the body control device 19 determines the previous adoption area among the focus detection areas 45a to 45k, that is, the focus detection area where the previous adoption defocus amount is detected, and the focus detection areas located in the vicinity thereof. A focus detection signal from the distance measuring element 10 is acquired and a defocus amount is calculated. For example, if the previous adoption area is the focus detection area 45a in FIG. 7B, the defocus amount D [a] and the focus detection areas 45b, 45d, 45e, and 45f adjacent to the focus detection area 45a. Each defocus amount D [b], D [d], D [e] and D [f] is calculated.

  In step S111, the body control device 19 selects a defocus amount having the smallest difference from the previous adopted defocus amount among the defocus amounts calculated in step S110. For example, in the above example, among the calculated defocus amounts D [b], D [d], D [e], and D [f], the defocus amount D [f] is the difference from the previous adopted defocus amount. Is the smallest, the defocus amount D [f] is selected.

  In step S112, the body control device 19 determines whether or not the difference between the defocus amount selected in step S111 and the previous adopted defocus amount is within a predetermined value. If these differences are within a predetermined value, the process proceeds to step S113, and in step S113, the defocus amount selected in step S111 is adopted and determined as the current adopted defocus amount. That is, in the above example, the defocus amount D [f] is set as the currently adopted defocus amount. After executing Step S113, the body control device 19 ends the second half focus detection calculation process and proceeds to Step S72 in FIG.

On the other hand, if the difference between the defocus amount selected in step S111 and the previous adopted defocus amount is greater than or equal to a predetermined value, the body control device 19 proceeds to step S114. In step S114, the body control device 19 determines that no effective defocus amount has been detected this time, and does not determine any calculated defocus amount as the adopted defocus amount, and does not adopt the defocus amount. After executing step S114, the body control device 19 ends the second half focus detection calculation process and proceeds to step S72 in FIG. In this case, drive control of the focusing lens 8b is not performed in the focus adjustment control in step S72, and therefore the focus adjustment state of the photographing lens 8 does not change.

  In addition, in the first half focus detection calculation process executed in step S67 of FIG. 11, if the defocus amount targeted for calculation in step S102, S106 or S110 has already been calculated, the defocus amount is calculated. Omitted. Thereby, for the focus detection area for which the defocus amount is obtained in the first half focus detection calculation process, the body control device 19 executes the second half focus detection calculation process to detect the focus adjustment state of the photographing lens 8. Prohibit that.

  By executing the latter half focus detection calculation process as described above in step S71 in FIG. 11, the focus detection area corresponding to the position of the image corresponding to the reference information recognized by the image tracking calculation in step S70 is obtained. The defocus amount is detected, and the adopted defocus amount used for the current focus adjustment is determined. Based on this adopted defocus amount, focus adjustment control is performed in step S72, so that the focus adjustment state of the photographing lens 8 is appropriately changed during continuous shooting according to the movement of the subject.

According to the embodiment described above, the following operational effects can be obtained.
(1) In the camera 1 of the present embodiment, the second image sensor 16 captures an image by the photographing lens 8 and outputs image information. The body control device 19 obtains a defocus amount indicating the focus adjustment state of the photographing lens 8 based on the focus detection signal from the distance measuring element 10. In addition, the body control device 19 stores the template image information 48 as reference information relating to an image, and executes an image tracking calculation to perform tracking corresponding to image information output from the second image sensor 16. The position of the image corresponding to the reference information in the work image is recognized. Further, before executing the image tracking calculation in step S70 and recognizing the position of the image, the body control device 19 performs the first-half focus detection calculation process for obtaining the defocus amount in step S67, and in step S70, the image tracking calculation In step S71, the latter half focus detection calculation process for obtaining the defocus amount is performed on the position of the image recognized by executing the above. Since it did in this way, the calculation of the defocus amount can be performed as much as possible before executing the image tracking calculation, and the calculation of the defocus amount performed after the execution of the image tracking calculation can be reduced. Therefore, efficient control can be performed within a limited calculation processing time.
(2) The body control device 19 detects defocus amounts for the plurality of focus detection areas 45 a to 45 k set for a plurality of positions in the image plane of the photographing lens 8. Further, in the latter half focus detection calculation process performed in step S71, the body control device 19 detects the focus belonging to the range corresponding to the position of the image recognized by the image tracking calculation in step S70 among the plurality of focus detection areas 45a to 45k. The defocus amount is obtained for the area (steps S102 and S106). Since it did in this way, the defocus amount for performing a focus adjustment according to the motion of the to-be-tracked subject can be detected quickly.
(3) In the first half focus detection calculation process performed in step S67, the body control device 19 applies to the focus detection area previously selected as the previous adopted area and its peripheral area among the plurality of focus detection areas 45a to 45k. Thus, the defocus amount was determined. Since it did in this way, even before performing tracking object calculation, it is possible to detect the defocus amount for a range in which there is a high possibility that a subject to be tracked exists.
(4) The body control device 19 performs the step S102 or S106 for the focus detection area for which the defocus amount is obtained in the first half focus detection calculation process in step S67 among the plurality of focus detection areas 45a to 45k. It was decided to prohibit the defocus amount. Since it did in this way, calculation of an unnecessary defocus amount can be omitted and calculation processing time can be shortened.
(5) The body control device 19 determines whether or not the tracking area corresponding to the reference information can be specified by the image tracking calculation in step S70 (step S101). If the tracking area cannot be specified and the position of the reference information cannot be recognized in the tracking image, it is prohibited to detect the focus adjustment state of the photographic lens 8 by executing the latter half focus detection calculation processing after step S101. It was decided. Since it did in this way, the calculation processing time can be shortened by omitting the calculation of the defocus amount which becomes unnecessary when the image tracking fails.
(6) The body control device 19 can selectively set the tracking priority mode and the selection area priority mode. In the tracking priority mode, by executing the latter half focus detection calculation process in step S71, the defocus amount corresponding to the position of the target image recognized by the image tracking calculation in step S70 is obtained by the first half focus detection calculation process in step S67. The detected defocus amount is used with priority (steps S105 and S109). On the other hand, in the selection area priority mode, the selection area priority focus detection calculation process is executed in step S58, thereby adopting the defocus amount for the user selection area or its peripheral area among the plurality of focus detection areas 45a to 45k ( Steps S84 and S88). At this time, the defocus amount is not calculated after the image tracking calculation in step S64. Since it did in this way, one mode can be set according to a user's usage form, and focus adjustment control can be performed appropriately.
(7) The body control device 19 adjusts the focus of the photographic lens 8 based on the defocus amount obtained based on the focus detection signal from the distance measuring element 10. In particular, during continuous shooting in which imaging by the first imaging element 4 is repeated a plurality of times, the first half focus detection calculation processing in step S67 and the second half focus detection calculation in step S71 are performed at intervals of the plurality of imaging. . Since it did in this way, focus adjustment of the photographic lens 8 can be performed appropriately within the limited calculation processing time.

  In the above embodiment, an example in which focus detection is performed using the independent distance measuring element 10 has been described. However, a pair of light beams that have passed through different portions of the pupil of the photographing lens in the imaging pixel array of the first imaging element 4. Alternatively, focus detection pixels that receive light may be mixedly arranged, and the focus adjustment state may be obtained using the output of the focus detection pixels. Further, instead of the second image sensor, tracking and photometry may be performed using the output of the first image sensor.

DESCRIPTION OF SYMBOLS 1 Camera 2 Camera main body 4 1st image pick-up element 8 Shooting lens 10 Distance measuring element 16 2nd image pick-up element 19 Body control apparatus

Claims (5)

A defocus amount calculation unit for calculating the defocus amount;
A determining unit that determines the defocus amount of the focus detection area used for driving control of a focus optical system among a plurality of focus detection areas;
A control unit that performs drive control of a focus optical system using the defocus amount determined by the determination unit;
An acquisition unit that acquires first information related to a position of the focus detection area used for driving control of the focus optical system by the control unit;
A tracking unit that obtains second information related to the position of the tracking target using reference information that includes information on the tracking target and image information that is repeatedly acquired by the imaging unit;
The defocus amount calculation unit calculates a first defocus amount for at least one focus detection area selected using the first information before the calculation by the tracking unit is completed .
After the calculation by the tracking unit is completed, a second defocus amount is calculated for at least one focus detection area selected using the second information ,
The determination unit includes at least one of the first defocus amount and the second defocus amount, and a third defocus amount that is a defocus amount used for driving control of the focus optical system by the control unit. An imaging apparatus characterized in that the defocus amount used for driving control of the focus optical system is determined by comparison . The imaging apparatus according to claim 1,
The determination unit uses the second defocus amount for driving control of the focus optical system when a difference between the third defocus amount and the second defocus amount is within a first predetermined value. And the difference between the third defocus amount and the second defocus amount is greater than the first predetermined value, and the difference between the third defocus amount and the first defocus amount is a second predetermined value. An imaging apparatus characterized in that, when smaller, the first defocus amount is determined as the defocus amount used for driving control of the focus optical system. The imaging apparatus according to claim 1 or 2 ,
The defocus amount calculation unit calculates the first defocus amount and the second defocus amount during a period between the first shooting at the time of continuous shooting and the second shooting after the first shooting , The imaging apparatus according to claim 1, wherein the first defocus amount is calculated before the calculation by the tracking unit is completed. The imaging apparatus according to claim 3 ,
The defocus amount calculation unit is configured to detect the second defocus amount for the focus detection area in which the defocus amount is calculated by calculating the first defocus amount during a period between the first shooting and the second shooting. imaging apparatus characterized by not calculating the defocus amount in the focus of computation. The imaging apparatus according to claim 1 , wherein:
The imaging device is a photometric sensor used for photometry.