JP3733228B2 - Imaging device with tilt mechanism, method, and storage medium - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a tilt correction technique in which a lens or an image sensor is rotated by a tilt mechanism in a video camera, an electronic still camera, or the like to focus on a plurality of subjects.
[0002]
[Prior art]
As a camera capable of focusing on a plurality of subjects, a system in which a tilt mechanism is incorporated in an interchangeable lens of a 35 mm single lens reflex camera is known. In addition, many large cameras are equipped with a lens or a tilt mechanism for tilting a film. These tilt mechanisms are all based on manual operation, and require a photographer's skill to focus on a plurality of subjects.
[0003]
In addition, an autofocus (AF) camera that measures distances at multiple points is known in order to achieve a substantially in-focus state with respect to a plurality of subjects without using a tilt mechanism. As an example of this, there is a camera that adjusts the focus so that a plurality of subjects are within the depth of field (Japanese Patent Laid-Open No. 62-52538). This type of method reduces the possibility of focusing failure by selecting one of a plurality of pieces of focusing information or taking an average, and does not actively focus. .
[0004]
Further, as described in Japanese Patent Laid-Open No. 2-79808 and the like, the film surface is automatically adjusted so that a plurality of subjects having different subject distances are measured and focused on the plurality of subjects. A camera with an automatic tilt mechanism that can tilt the lens is known.
[0005]
However, this automatic tilting device requires a multipoint distance measuring sensor that can measure at least three portions of the subject. In particular, in a camera that obtains a subject image with an image sensor, such as a video camera or an electronic still camera, since a sensor for distance measurement is provided in addition to the image sensor, the structure of the apparatus becomes complicated and it is not suitable for miniaturization, etc. There were drawbacks.
[0006]
As a tilting device that solves these problems, a TTL video automatic tilting device that drives the tilting mechanism so as to maximize the high-frequency component of the video signal output from the image sensor has been realized (Japanese Patent Laid-Open No. Hei 4- (1999)). 196878).
[0007]
The conventional TTL video system tilt device will be briefly described below.
[0008]
17 and 18 are diagrams for explaining the Scheinproof law, which is the principle of tilt photography. In general, if the photographic lens system 1 and the image sensor 2 are parallel, the entire area of the subject 20 is not focused when the subject 20 is paid. In order to focus on the entire area, the intersection point P between the imaging surface of the imaging device 2 and the subject surface may intersect with the main plane of the photographing lens system 1. This is a law called Scheinproof's law. When this Scheinproof's law is actually applied, the imaging device 2 is tilted with respect to a plane perpendicular to the optical axis as shown in FIG. In some cases, the photographic lens system 1 is tilted.
[0009]
FIG. 19 is a block diagram showing a conventional automatic tilting device. In FIG. 19, reference numeral 1 denotes a photographic lens system, and this photographic lens system 1 is composed of optical lens groups 101, 102, and 104 and a diaphragm 103. Reference numeral 104 denotes a rotating lens group. When the rotating lens group 104 rotates, tilt correction is performed. Reference numeral 2 denotes an image sensor, which converts a subject image obtained by the optical system into an electrical image signal. Reference numeral 3 denotes a signal processing circuit that performs processing such as amplification, and reference numeral 4 denotes a high-frequency component extraction circuit that extracts high-frequency components from the image signal. Reference numeral 6 denotes a control signal generation circuit for driving and controlling the tilt motor. Reference numeral 8 denotes a tilt motor driving circuit. Reference numeral 12 denotes a tilt motor composed of a stepping motor, an ultrasonic motor, and the like. Reference numeral 13 denotes a motor gear that is attached to the tilt motor 12 and rotates integrally with the motor. Reference numeral 14 denotes a rotating lens frame that rotates the motor gear 13 later. 15 is a transmission gear to be transmitted to 15. Reference numeral 15 denotes a rotating lens frame that holds the rotating lens group 104 and rotates integrally with the rotating lens group 104.
[0010]
In the state where the main plane of the photographic lens system 1 and the imaging surface of the image sensor 2 are parallel, that is, when the tilt correction is not performed, when the subject is slanted, the imaging plane of the subject and the image sensor 2 The imaging surfaces do not overlap over the entire surface and do not focus over the entire area of the subject. Since the subject image of the out-of-focus portion is taken out of focus, the high-frequency component of the video signal is reduced.
[0011]
Therefore, the tilting lens group 104 is micro-rotated, and the tilt mechanism is controlled based on the polarity and magnitude of the change amount of the output signal of the high-frequency component extraction circuit 4 that is changed by the micro-rotation. The tilt correction can be performed by driving and controlling the rotating lens group 104 so that the high-frequency component of the output signal 2 is maximized.
[0012]
[Problems to be solved by the invention]
However, the conventional automatic tilting device has the following problems. This problem will be described with reference to FIG. 20, FIG. 21, and FIG.
[0013]
20, 21, and 22, 21 is a subject surface, 22 is a main plane of a photographic lens system, 23 is an imaging surface of an image sensor, and 24 is an object that is optically determined by the photographic lens system and the imaging surface 23. A focusing surface on the side (hereinafter referred to as an object surface), 25 is an imaging surface on which the subject surface is imaged by the photographing lens system.
[0014]
FIG. 20 shows a state where the tilt correction is not performed. In this state, the subject image at the intersection M between the subject plane 21 and the object plane 24 is imaged at the intersection M ′ between the imaging plane 23 and the imaging plane 25. The subject image located at is out of focus.
[0015]
Therefore, in the conventional automatic tilting device, as shown by the arrow in FIG. 21, the imaging surface 23 is tilted so that the imaging surface 23 coincides with the imaging surface 25, thereby matching the entire area of the subject surface 21. It is in a focused state.
[0016]
However, in this case, it is necessary to incline the imaging surface 23 with the intersection M ′ between the imaging surface 23 and the imaging surface 25 as the rotation center. In other words, before tilt correction, the subject image must be formed at the center of rotation when the imaging surface 23 is tilted. However, in the tilt mechanism, in order to be able to arbitrarily set the rotation center when the imaging surface 23 is tilted, the mechanism becomes very complicated. This rotation center is the center of the imaging surface 23, That is, it is set on the optical axis.
[0017]
Accordingly, for example, as shown in FIG. 22, when there is no subject image at the rotation center O when the imaging surface 23 is tilted, in other words, when there is no subject at the object point O ′ of the rotation center O on the imaging surface 23. Will not be able to perform automatic tilt correction. A similar problem occurs when the photographing lens system is tilted.
[0018]
The present invention has been made under such a background, and the problem is that a tilt mechanism for rotating an optical image input medium about a certain rotation center is based on an image signal obtained from an image sensor. Thus, when focusing on a plurality of subjects by driving control, it is possible to reliably focus on a plurality of subjects having different subject distances without being affected by the position of the subject.
[0019]
[Means and Actions for Solving the Problems]
  In order to solve the above-described problems, the present invention provides an imaging apparatus having an inclination mechanism that rotates an input medium of an optical image about a fixed rotation center, from an imaging element to a lens focus position that is infinite from the nearest. First detection means for detecting focus information of the subject image from the obtained image signal; second detection means for detecting a maximum value from the focus information detected by the first detection means; When the plurality of maximum values are detected by the second detection unit corresponding to a plurality of different subjects, the tilt mechanism is driven so that the distance between the lens focus positions corresponding to the plurality of maximum values is minimized. First control means for controlling;After the drive control by the first control means is performed,Second control means for driving and controlling the tilt mechanism so that the maximum value is maximized.
[0020]
  Further, the present invention provides an imaging method including an tilt mechanism that rotates an input medium of an optical image about a fixed rotation center, from an image signal obtained from an imaging device with respect to an infinite lens focus position from the nearest. A first detection step for detecting focus information of a subject image, a second detection step for detecting a maximum value from the focus information detected by the first detection step, and a plurality of subjects having different subject distances. Correspondingly, when a plurality of maximum values are detected by the second detection step, the first tilt mechanism is driven and controlled so that the interval between the lens focus positions corresponding to the plurality of maximum values is minimized. Control process;After the drive control by the first control step is performed,A second control step of driving and controlling the tilt mechanism so that the maximum value is maximized.
[0021]
  Further, the present invention is a storage medium storing a control program for focusing on a plurality of subjects using a tilt mechanism that rotates an input medium of an optical image around a fixed rotation center, The control program includes a first detection routine for detecting focus information of a subject image from an image signal obtained from an image sensor at an infinite lens focus position from the closest distance, and an alignment detected by the first detection routine. When a plurality of maximum values are detected by the second detection routine corresponding to a plurality of subjects having different subject distances, and a plurality of maximum values are detected corresponding to a plurality of subjects having different subject distances. A first control routine for driving and controlling the tilt mechanism so that the distance between corresponding lens focus positions is minimized;After the drive control by the first control routine is performed,And a second control routine for driving and controlling the tilt mechanism so that the maximum value is maximized.
[0022]
In the present invention, the first detection means, the process, and the routine detect a high frequency component of the image signal as the focusing information.
[0023]
In the present invention, the first detection means, the process, and the routine detect the sharpness of the edge shape of the image signal as the focusing information.
[0024]
  In the present invention, the tilt mechanism is an input medium for the optical image.Is set on the optical axisHas been.
[0025]
In the present invention, the tilt mechanism is configured to rotate part or all of a photographing lens system as an input medium for the optical image.
[0026]
In the present invention, the tilt mechanism is configured to rotate the image sensor as an input medium for the optical image.
[0027]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below with reference to the drawings.
[0028]
[First Embodiment]
FIG. 1 is a schematic configuration diagram of an imaging apparatus with a tilt mechanism according to the first embodiment of the present invention. In FIG. 1, reference numeral 1 denotes a photographic lens system, and this photographic lens system 1 is composed of optical lens groups 101, 102, and 104 and a diaphragm 103. Reference numeral 104 denotes a rotating lens group, and rear-orientation correction is performed by rotating the rotating lens group 4. Reference numeral 2 denotes an image sensor, which converts a subject image obtained by the optical system into an electrical image signal. Reference numeral 3 denotes a signal processing circuit that performs processing such as amplification, and reference numeral 4 denotes a high-frequency component extraction circuit that extracts high-frequency components from the image signal. Reference numeral 5 denotes a maximum value detection circuit for detecting a maximum value of the high frequency component.
[0029]
Reference numeral 6 denotes a control signal generation circuit for generating a control signal for driving and controlling a focus motor 9 and a tilt motor 12, which will be described later, in order to perform tilt correction unique to the present invention. The control signal generation circuit 6 is constituted by a microcomputer and includes a CPU 61, a ROM 62, and a RAM 63. The ROM 62 is preset with an inclination correction program corresponding to the flowcharts of FIGS. 2 and 3, and the CPU 61 performs an inclination correction process using the RAM 63 as a work area or the like according to the inclination correction program.
[0030]
7 is a focus motor drive circuit, and 8 is a tilt motor drive circuit. Reference numeral 9 denotes a focus motor composed of a stepping motor, an ultrasonic motor, etc., 10 denotes a motor gear attached to the focus motor 9 and rotates integrally with the motor, and 11 denotes a transmission gear for transmitting the rotation of the motor gear 10 to the photographing lens system 1. It is. A normal focus adjustment is performed by driving the focus motor 9 to move the photographing lens system 1 back and forth on the optical axis.
[0031]
  Reference numeral 12 denotes a tilt motor composed of a stepping motor, an ultrasonic motor, and the like. Reference numeral 13 denotes a motor gear that is attached to the tilt motor 12 and rotates integrally with the motor. Reference numeral 14 denotes rotation of the motor gear 13 to a rotating lens frame 15 described later. It is a transmission gear. Reference numeral 15 denotes a rotating lens frame that holds the rotating lens group 104 and rotates integrally with the rotating lens group 104. The tilt motor 12 is driven to rotate the rotating lens frame 15 and the rotating lens group 104, and the tilt correction is performed by tilting the main plane of the rotating lens group 104 with respect to the plane perpendicular to the optical axis. . The rotation center of the rotation lens group 104 is set on the optical axis.The
[0032]
Next, the tilt correction operation in the first embodiment will be described with reference to FIGS.
[0033]
First, the CPU 61 of the control signal generating circuit 6 rotates the rotating lens group 104 so that the photographing lens system 1 and the image pickup device 2 are in a parallel state, that is, in a state where the tilt correction is not performed (FIG. 2). Step S201). Then, the maximum value detection operation shown in detail in FIG. 3 is performed (step S202). That is, the CPU 61 first moves the photographic lens system 1 to the closest lens focus position in order to sequentially scan the photographic lens system 1 from the closest to infinity lens focus position by the focus motor 9 (step S301 in FIG. 3). ). At this time, the image pickup device 2 outputs an image signal at the lens focus position, and the image signal is input to the high frequency component extraction circuit 4 via the signal processing circuit 3. The high frequency component of the image signal is extracted as focusing information by the extraction circuit 4 (step S302).
[0034]
Next, the photographing lens system 1 is slightly moved in the direction of the lens focus position at infinity (step S303), and the same high frequency component detection processing as that in step S302 is performed (step S304). Then, it is determined whether or not the current position of the photographic lens system 1 is an infinite lens focus position (step S305). If not, the process returns to step S303 and the same processing is performed. repeat. On the other hand, if the lens focus position is at infinity, a maximum value detection circuit is selected from the high-frequency components of the image signal obtained by sequentially scanning the photographic lens system 1 from the closest focus position to the lens focus position at infinity as described above. 5, the maximum value is detected (step S306).
[0035]
By the way, the high frequency component of the image signal increases in the vicinity of the in-focus state. Therefore, as shown in FIG. 4, when a plurality of subjects A, B, and C having different subject distances are present in the object scene, the high frequency components extracted by the high frequency component extraction circuit 4 are as shown in FIG. . In FIG. 5, a indicates the focus position of the subject in FIG. Similarly, b and c indicate the focus positions of the B and C subjects, respectively. In general, when a subject exists at a plurality of lens focus positions, a plurality of maximum values are detected as shown in FIG. 5, and in this case, the maximum value detection circuit 5 corresponds to the maximum value and the maximum value. The lens focus position is output.
[0036]
When a plurality of maximum values are detected in this way (step S203 in FIG. 2), the CPU 61 of the control signal generation circuit 6 outputs a control signal for driving the tilt motor 12 to the tilt motor drive circuit 8. Then, the tilting lens group 104 is slightly rotated by driving the tilt motor 120 (step S204). Then, the above-described maximum value detection operation is performed again (step S205), and it is determined whether or not the distance between the lens focus positions corresponding to a plurality of maximum values is minimized (step S206). As a result, if not the minimum, the process returns to step S204 and the same processing is repeated. On the other hand, when the distance between the lens focus positions corresponding to a plurality of maximum values is minimized, the minute rotation of the rotating lens group 104 and the maximum value detection operation are repeated again, and this time the maximum value is maximized. The rotation lens group 104 is controlled so as to become (Steps S207 to S209).
[0037]
Here, if the lens is slightly rotated in the T direction in FIG. 4, the relationship between the high frequency component and the lens focus position is as shown in FIG. In FIG. 6, a ′, b ′, and c ′ indicate the lens focus positions of the subjects A, B, and C after the rotating lens group 104 is slightly rotated. In FIG. 6, since the rotating lens group 104 is slightly rotated in the tilt correction direction, the distance between the lens focus positions a ′, b ′, and c ′ is the lens focus position a, b, before tilt correction in FIG. It is narrower than the interval of c. Conversely, the distance between the lens focus positions when the rotating lens group 104 is rotated in the direction of T ′ in FIG. 2 is omitted, but the lens focus positions a, b, It becomes wider than the interval of c. As described above, when the interval between the lens focus positions becomes wide when the rotating lens group 104 is rotated, the rotation direction is immediately reversed in the processing loop of steps S204 to S206.
[0038]
In this way, the minute rotation of the rotating lens group 104 and the maximum value detection operation are repeated, and as shown in FIG. 7, there is one lens focus position at which the maximum value can be obtained, or the interval between the plurality of lens focus positions is the largest. When the angle becomes narrow, the minute rotation of the rotation lens group 104 and the maximum value detection operation are repeated again, and the rotation lens group 104 is controlled to rotate so that the maximum value is maximized.
[0039]
Then, when the maximum value reaches the maximum as shown in FIG. 8, the rotation of the rotating lens group 104 is stopped. Next, in this state, the focus motor 9 is driven to move the photographing lens system 1 to the lens focus position x where the maximum maximum value Vmax is obtained (step S210), and the tilt correction is ended. By performing the photographing operation in the state where the tilt correction is performed in this way, it is possible to obtain an image signal focused on a plurality of subjects having different subject distances.
[0040]
Next, a case where the subject is uniformly present on a plane in which the subject distance changes linearly, such as a character written on paper or the like, will be described with reference to FIGS. 9 and 10.
[0041]
In FIG. 9, reference numeral 20 denotes a subject that exists uniformly on a plane in which the subject distance changes linearly. When such a subject 20 is photographed, the high-frequency component of the image signal when the photographing lens system 1 is sequentially scanned from the closest to the infinity lens focus position without performing tilt correction is as shown in FIG. Is uniform in the range from m to n, and one maximum value is detected.
[0042]
As in this case, when it is determined in step S203 in FIG. 2 that the number of local maximum values is one, the distance between the lens focus positions corresponding to the plurality of local maximum values in steps S204 to S206 is the smallest. The process of rotating the rotating lens group 104 so as to become is skipped, and the processing of steps S207 to S209, that is, the minute rotation of the rotating lens group 104 and the maximum value detecting operation are repeated, and the magnitude of the maximum value is repeated. The rotation lens group 104 is controlled so as to be maximized. Then, when the maximum value reaches the maximum, the rotation of the rotating lens group 104 is stopped, and the focus motor 9 is driven to obtain the maximum local value Vmax at the lens focus position x where the photographing lens system 1 is obtained. Is moved (step S210), and the tilt correction is terminated. Also in this case, an in-focus image signal can be obtained in all areas of the subject 20.
[0043]
[Second Embodiment]
FIG. 11 is a schematic configuration diagram of an imaging apparatus with a tilt mechanism according to the second embodiment of the present invention. In FIG. 11, the same components as those in the first embodiment shown in FIG.
[0044]
In FIG. 11, reference numeral 1 denotes a photographic lens system, and this photographic lens system 1 is composed of optical lens groups 101, 102, and 105 and a diaphragm 103. Reference numeral 17 denotes a transmission gear that transmits the rotation of the tilt motor 12 to the imaging element rotation frame 18 described later via the motor gear 13. Reference numeral 18 denotes an image sensor rotation frame that rotates integrally with the image sensor 2.
[0045]
In the present embodiment, the tilt correction is performed by rotating the image sensor 2 instead of rotating the lens as in the first embodiment. The control operation for tilt correction is exactly the same as in the first embodiment. Note that the rotation center of the image sensor 2 is set on the optical axis.
[0046]
When the image pickup device 2 is rotated as in the present embodiment, the image pickup device 2 is lighter than the optical system. Therefore, a small and light motor can be used as the tilt motor 12, and the entire apparatus. This is advantageous for reducing size and weight. In addition, an optical system having no tilt correction function can be used as it is, and lens replacement is facilitated.
[0047]
[Third and Fourth Embodiments]
In the first and second embodiments, the high-frequency component of the image signal is used as the focus information of the subject image. As the focus information, any information having a maximum value or a minimum value at the subject position can be used. Such information may be used. For example, information on the edge shape of the image signal may be used. Therefore, in the third and fourth embodiments, the edge shape information of the image signal is used as the focusing information.
[0048]
FIGS. 12 and 13 are schematic configuration diagrams of an imaging apparatus with a tilt mechanism according to the third and fourth embodiments, respectively. As a mechanical tilt mechanism in the third embodiment of FIG. The lens is configured to rotate as in the embodiment, and the mechanical tilt mechanism in the fourth embodiment of FIG. 13 is configured to rotate the image sensor 2 as in the second embodiment. Has been. Note that the rotation centers of these tilt mechanisms are all set on the optical axis.
[0049]
As an electrical configuration for performing the tilt correction, as shown in FIGS. 12 and 13 in any of the third and fourth embodiments, the high frequency range in the first and second embodiments is used. Instead of the component extraction circuit 4, an ES filter 19 for obtaining an ES value indicating the sharpness of the edge of the image signal is provided.
[0050]
A focus information detection method (ES method) using edge shape information is disclosed in US Pat. No. 4,804,831, and will be described only briefly. FIG. 14 is a diagram illustrating a configuration example of the ES filter 19. In FIG. 14, 31 is a differentiation circuit, 32 is an absolute value circuit, 33 is a delay circuit, 34 is an integration circuit, and 35 is a division circuit. The integrating circuit 34 includes two delay circuits 34a and 34b and one adding circuit 34c.
[0051]
Next, the function of the ES filter 19 shown in FIG. 14 will be described with reference to the waveform diagram of FIG.
[0052]
FIG. 15A is a waveform diagram of an image signal, and the edge of the image signal has a steep slope when focused and a gentle slope when not focused. FIG. 15B is a differential waveform diagram obtained by differentiating the image signal of FIG. 15 (c) and 15 (d) show the differential waveforms (strictly speaking, the signals whose polarities are unified positively by the absolute value circuit 32) of the delay circuits 33 and 34a and the delay circuit 34b, respectively. It is the wave form diagram delayed by. FIG. 15 (e) is an integrated waveform diagram obtained by integrating the waveforms of FIGS. 15 (b), (c), and (d) by the integrating circuit 34. The integrated waveform indicates the contrast of the edge portion of the image signal. Represents.
[0053]
FIG. 15 (f) shows a waveform obtained by dividing the differential waveform of FIG. 15 (b) by the integral waveform of FIG. 15 (e) by the division circuit 35, and the division circuit 35 shows this divided value. Is output as an ES value indicating the sharpness of the edge. This ES method is characterized by being unaffected by the size, contrast, and illumination of the subject.
[0054]
FIG. 16 is a diagram illustrating changes in the lens position and the ES value when the AF operation is performed in order to obtain the in-focus position. The lens feed is continuously sent from the minimum position (closest) to the maximum position (infinite). During this period, the image signal is accumulated in the image sensor 2 every one vertical scanning period, and the image signal is read out by the ES filter 19. The ES value is obtained from the image signal, and the position where the ES value is the largest is detected by the maximum value detection circuit 5 and detected as the in-focus position, that is, the maximum value.
[0055]
A curve with the peak at the in-focus position drawn when the lens feed amount is taken on the horizontal axis and the focus signal (ES value in this case) is taken on the vertical axis is called a hill-climbing curve. There is a feature that the accuracy of focus detection is good.
[0056]
Note that the present invention is not limited to the above-described embodiment, and can be applied to, for example, a tilt mechanism that rotates the entire photographic lens system without rotating a part of the photographic lens system. is there.
[0057]
【The invention's effect】
  As described above, according to the present invention, in the imaging apparatus including the tilt mechanism that rotates the input medium of the optical image around the fixed rotation center, the imaging element is in the range from the closest to the infinite lens focus position. First detection means for detecting focus information of the subject image from the image signal obtained from the second detection means for detecting the maximum value from the focus information detected by the first detection means, and subject distance When the plurality of maximum values are detected by the second detection unit corresponding to a plurality of different subjects, the tilt mechanism is set so that the distance between the lens focus positions corresponding to the plurality of maximum values is minimized. First control means for driving control;After the drive control by the first control means is performed,And a second control unit that drives and controls the tilt mechanism so that the maximum value is maximized. Therefore, the tilt mechanism that rotates the input medium of the optical image about a fixed rotation center is provided. When focusing on multiple subjects by driving control based on the image signal obtained from, it is possible to reliably focus on multiple subjects with different subject distances without being affected by the position of the subject It becomes.
[Brief description of the drawings]
FIG. 1 is a schematic configuration diagram of an imaging apparatus with a tilt mechanism according to a first embodiment of the present invention.
FIG. 2 is a flowchart showing tilt correction processing according to first to fourth embodiments of the present invention.
FIG. 3 is a flowchart showing in detail a maximum value detection process in FIG. 2;
FIG. 4 is a diagram illustrating a first subject example.
5 is a diagram illustrating a relationship between a high frequency component of an image signal before tilt correction corresponding to the subject example of FIG. 4 and a lens focus position.
6 is a diagram illustrating a relationship example between a high-frequency component of an image signal and a lens focus position after first-stage tilt correction processing corresponding to the subject example of FIG. 4;
7 is a diagram illustrating another example of the relationship between the high-frequency component of the image signal after the first-stage tilt correction processing and the lens focus position corresponding to the subject example of FIG. 4;
FIG. 8 is a diagram illustrating another example of the relationship between the high-frequency component of the image signal after the second-stage tilt correction process and the lens focus position.
FIG. 9 is a diagram illustrating a second subject example.
10 is a diagram illustrating an example of a relationship between a high-frequency component of an image signal after a first-stage tilt correction process and a lens focus position corresponding to the second subject example of FIG. 9;
FIG. 11 is a schematic configuration diagram of an imaging apparatus with a tilt mechanism according to a second embodiment of the present invention.
FIG. 12 is a schematic configuration diagram of an imaging apparatus with a tilt mechanism according to a third embodiment of the present invention.
FIG. 13 is a schematic configuration diagram of an imaging apparatus with a tilt mechanism according to a fourth embodiment of the present invention.
14 is a block diagram showing a configuration of an ES filter in FIGS. 12 and 13. FIG.
15 is a diagram showing signal waveforms at various parts of the ES filter of FIG. 14;
FIG. 16 is a diagram showing a hill-climbing curve in the ES method.
FIG. 17 is a diagram for explaining the Shineproof law when the image sensor is tilted;
FIG. 18 is a diagram for explaining Scheinproof's law when the photographic lens system is tilted;
FIG. 19 is a diagram showing a schematic configuration of a conventional TTL type automatic tilting device.
FIG. 20 is a diagram for explaining problems of a conventional TTL type automatic tilting device.
FIG. 21 is a diagram for explaining a problem of a conventional TTL type automatic tilting device.
FIG. 22 is a diagram for explaining a problem of a conventional TTL type automatic tilting device.
[Explanation of symbols]
1 ... Photography lens system
2 ... Image sensor
4 ... High frequency component extraction circuit
5 ... Maximum value detection circuit
6 ... Control signal generation circuit
12 ... Tilt motor
13. Motor gear
14, 17 ... Transmission gear
19 ... ES filter
61 ... CPU
62 ... ROM
63 ... RAM
104 ... Rotating lens group

Claims (18)

In an imaging apparatus provided with a tilt mechanism that rotates an input medium of an optical image around a fixed rotation center,
First detection means for detecting focus information of a subject image from an image signal obtained from an image sensor at an infinite lens focus position from the nearest;
Second detection means for detecting a maximum value from the focus information detected by the first detection means;
When a plurality of maximum values are detected by the second detection means corresponding to a plurality of subjects having different subject distances, the tilt angle is adjusted so that the distance between the lens focus positions corresponding to the plurality of maximum values is minimized. First control means for driving and controlling the mechanism;
Second control means for driving and controlling the tilt mechanism so that the maximum value is maximized after the drive control by the first control means is performed;
An imaging apparatus comprising:   The imaging apparatus according to claim 1, wherein the first detection unit detects a high-frequency component of the image signal as the focusing information.   The imaging apparatus according to claim 1, wherein the first detection unit detects a sharpness of an edge shape of the image signal as the focusing information. The imaging apparatus according to claim 1, wherein the tilt mechanism has a rotation center of the input medium of the optical image set on an optical axis.   The imaging apparatus according to claim 1, wherein the tilt mechanism is configured to rotate part or all of a photographing lens system as an input medium for the optical image.   The imaging apparatus according to claim 1, wherein the tilt mechanism is configured to rotate the imaging element as an input medium for the optical image. In an imaging method provided with a tilt mechanism that rotates an input medium of an optical image around a fixed rotation center,
A first detection step of detecting focus information of a subject image from an image signal obtained from an image sensor with respect to an infinite lens focus position from the nearest;
A second detection step of detecting a maximum value from the focusing information detected by the first detection step;
When a plurality of maximum values are detected by the second detection step corresponding to a plurality of subjects having different subject distances, the tilt angle is adjusted so that the interval between the lens focus positions corresponding to the plurality of maximum values is minimized. A first control step for driving and controlling the mechanism;
A second control step of driving and controlling the tilt mechanism so that the maximum value is maximized after the drive control by the first control step is performed;
An imaging method comprising:   The imaging method according to claim 7, wherein the first detection step detects a high frequency component of the image signal as the focus information.   The imaging method according to claim 7, wherein the first detection step detects a sharpness of an edge shape of the image signal as the focusing information. The imaging method according to claim 7, wherein the tilt mechanism has a rotation center of the input medium of the optical image set on an optical axis.   The imaging method according to claim 7, wherein the tilt mechanism is configured to rotate part or all of a photographing lens system as an input medium for the optical image.   The imaging method according to claim 7, wherein the tilt mechanism is configured to rotate the imaging device as an input medium for the optical image. A storage medium storing a control program for focusing on a plurality of subjects using a tilt mechanism that rotates an input medium of an optical image about a fixed rotation center, the control program comprising:
A first detection routine for detecting focus information of a subject image from an image signal obtained from an image sensor at an infinite lens focus position from the nearest;
A second detection routine for detecting a maximum value from the focus information detected by the first detection routine;
When a plurality of maximum values are detected by the second detection routine corresponding to a plurality of subjects having different subject distances, the tilt angle is adjusted so that the interval between the lens focus positions corresponding to the plurality of maximum values is minimized. A first control routine for driving and controlling the mechanism;
A second control routine for driving and controlling the tilt mechanism so that the maximum value is maximized after the drive control by the first control routine is performed;
A storage medium comprising:   The storage medium according to claim 13, wherein the first detection routine detects a high-frequency component of the image signal as the focus information.   14. The storage medium according to claim 13, wherein the first detection routine detects the sharpness of the edge shape of the image signal as the focusing information. 14. The storage medium according to claim 13, wherein the tilt mechanism has a rotation center of the optical image input medium set on an optical axis.   The storage medium according to claim 13, wherein the tilt mechanism is configured to rotate part or all of a photographing lens system as an input medium for the optical image.   The storage medium according to claim 13, wherein the tilt mechanism is configured to rotate the imaging device as an input medium for the optical image.

Images