JP4986588B2 - Imaging apparatus and control method thereof - Google Patents

Description

  The present invention relates to an imaging apparatus and a control method thereof, and more particularly to an imaging apparatus capable of capturing and recording moving images and still images and a control method thereof.

  In recent years, compact digital still cameras are generally available that can record not only still images but also moving images. Some digital cameras of this type do not perform an automatic focus adjustment (AF) operation during moving image recording, while others employ a continuous AF method in which an AF operation is continuously performed. A digital camera that performs continuous AF operation employs a so-called hill-climbing method that performs focus adjustment with the focus lens position where the high-frequency component of the luminance signal of the subject image formed on the image sensor is maximized as the in-focus position. There are many things.

  When performing continuous AF operation during video recording, in order to emphasize the continuity of the image, generally avoid moving the focus lens to the in-focus position in a short time, and focus on it over time. So that the focus lens is driven. Therefore, if you try to shoot a still image while recording a movie,

(1) If shooting is performed with the focus lens position at the time of the still image shooting instruction, the camera may not be in focus at that time and may be out of focus.
(2) During moving image recording, since the focus is taken over time, the release time lag may be longer than that during normal still image shooting.
There was a problem.
In order to deal with these problems, when a still image shooting instruction is given during moving image recording, a method of switching the imaging drive and performing an AF operation at a high speed can be considered. However, during AF operation for still image shooting, the image sensor is driven differently from that for moving image recording, so the image read for AF cannot be recorded as a moving image. Measures such as extending the interruption time were necessary.

  In order to achieve both the display and recording of moving images and the hill-climbing AF operation, there has been proposed a method of reading while alternately switching between continuous signal readout of the central part of the pixel and readout of the thinned-out signal of the entire region for each frame. (For example, refer to Patent Document 1). In this method, it is possible to perform an AF operation in which a part of an image is cut out in parallel while securing a constant frame rate.

Japanese Patent Laying-Open No. 2005-086245

  However, in the above conventional example, the image signal obtained during the AF operation is not the entire effective area but a part of the effective area, and cannot be used as an image for display and recording. Therefore, since the image for display and recording is created using only the thinned-out signal of the entire area of the pixels in the alternately switched frames, a reduction in the frame rate is inevitable. Further, when trying to perform an AF operation for a still image during moving image recording by this method, there is a problem that it is difficult to increase the speed because a signal for the AF operation can be read only every other frame.

  The present invention has been made in view of the above problems. In still image shooting during moving image recording, the interruption time of moving image recording can be minimized, and the AF operation for still image shooting can be completed in a shorter time. The purpose is to do so.

The image pickup apparatus according to the present invention is based on an image pickup device that outputs image data obtained by photoelectrically converting incident light, a drive control unit that drives the image pickup device, and image data output from the image pickup device. A focus adjustment unit that performs a focus adjustment process, a recording unit that records image data output from the imaging device, and a recording device that records a moving image when instructed to record a moving image by the drive control unit using the first driving method. The image data obtained by driving the element is recorded by the recording means, and when the photographing of a still image is instructed during moving image recording, the angle of view is the same as that of the first driving method, and the first The image data obtained by thinning driving the image sensor by the drive control means in the second driving method having a higher frame rate than the driving method corresponds to the image data obtained by the first driving method. Pixel And records by the recording means to convert performs focusing operation for still image shooting by the focus adjusting means on the basis of image data obtained by the second driving method, after focusing, the first Control means for controlling the recording means to record the image data obtained by driving the imaging device by the drive control means in a third driving method having a higher resolution than the driving method.

  According to the present invention, in still image shooting during moving image recording, the interruption time of moving image recording can be minimized, and the AF operation for still image shooting can be completed in a shorter time.

  The best mode for carrying out the present invention will be described below in detail with reference to the accompanying drawings.

  FIG. 1 is a block diagram showing a configuration of a digital still movie camera system according to the present embodiment.

  In FIG. 1, reference numeral 100 denotes a digital still movie camera device (hereinafter referred to as “camera device”). Reference numeral 10 denotes a photographing lens, and 11 denotes an optical viewfinder for confirming a subject image. The angle of view can be changed according to zoom control. Reference numeral 12 denotes a diaphragm combined shutter having a diaphragm function, and reference numeral 14 denotes an image sensor that converts an optical image into an electrical signal. A primary color mosaic filter is disposed on the element. The image sensor 14 is composed of pixels exceeding several tens to several millions, and can obtain a high-quality still image, and by performing thinning-out reading, the number of pixels and the frame rate determined by a known moving image standard It is also possible to read out pixel signals and shoot a moving image.

  Reference numeral 15 denotes a pre-processing circuit including a CDS (correlated double sampling) circuit and an AGC (automatic gain control) circuit for removing output noise of the image sensor 14, and 16 denotes an analog signal output from the pre-processing circuit 15. Is an A / D converter for converting the signal into a digital signal. Reference numeral 18 denotes a timing generation circuit (TG) that supplies a clock signal and a control signal to the image sensor 14 and the A / D converter 16, and their timing is controlled by the signal processing IC 22.

  In response to an instruction from the CPU 50, the signal processing IC 22 performs predetermined pixel interpolation processing, color conversion processing, enlargement / reduction processing (resize) processing, image data format conversion on the data from the A / D converter 16 or the data from the DRAM 30. Perform processing. It also includes a DMA (Direct Memory Access) controller, a D / A converter for display, and a compression / decompression circuit for compressing and decompressing image data. Further, the signal processing IC 22 performs predetermined arithmetic processing using the captured image data, and stores the obtained arithmetic result in the DRAM 30. The CPU 50 performs through-the-lens (TTL) auto white balance (AWB) processing, autofocus (AF) processing, automatic exposure (AE) processing, and flash pre-flash (EF) processing based on the calculation result. Yes.

  Reference numeral 28 denotes an image display unit composed of a TFT LCD or the like, and display image data written in the DRAM 30 is displayed on the image display unit 28 via a D / A converter (not shown) in the signal processing IC 22. The image display unit 28 is used to display various information / mode setting statuses in addition to images. An electronic viewfinder (EVF) function can be realized by sequentially displaying image data captured using the image display unit 28. Further, the image display unit 28 can arbitrarily turn on / off the display according to an instruction from the CPU 50. When the display is turned off, the power consumption of the camera device 100 can be greatly reduced.

  Further, the image display unit 28 is coupled to the camera body by a rotatable hinge unit, and can use an electronic finder function, a reproduction display function, and various display functions by setting a free orientation and angle. . Further, the display portion of the image display unit 28 can be stored while being directed toward the camera body. In this case, the storage state is detected by the detection switch (SW) 98 to display the image. The display operation of the unit 28 can be stopped.

  The DRAM 30 is a memory used for temporarily storing captured non-compressed data, holding calculation results of AF / AE / AWB / EF processing, holding a display image on the image display unit 28, holding compressed image data, and the like. . The DRAM 30 has a storage capacity sufficient to store a predetermined number of still images and a moving image for a predetermined time, and also has a work area for a program for causing the CPU 50 to execute.

  A zoom control circuit 44 controls zooming of the photographing lens 10 and the optical viewfinder 11.

  A connector 46 is also called an accessory shoe, and includes an electrical contact with the external flash device 400 and mechanical fixing means. A built-in flash 48 has a TTL light control function.

  Reference numeral 50 denotes a CPU that controls the entire camera apparatus 100. The CPU 50 performs AF / AE / AWB / EF control based on the calculation result of AF / AE / AWB / EF stored in the DRAM 30 by the signal processing IC 22. In addition, data flow control for the signal processing IC 22, various key scan operations, zoom control, communication with peripheral modules, and the like are performed. Reference numeral 52 denotes an electrically erasable / recordable flash memory in which a program necessary for operating the CPU 50, camera-specific adjustment data, and the like are written in advance.

  Reference numeral 54 denotes a notification unit for notifying the outside of an operation state, a message, and the like using characters, images, sounds, and the like in accordance with the execution of the program by the CPU 50. As the notification unit 54, for example, a display unit that performs visual display using a liquid crystal display device or an LED, a sound generation element such as a speaker that performs voice notification, and the like are used. The In particular, in the case of a display unit, it is installed at a single or a plurality of locations near the operation unit 70 of the camera device 100 that are easily visible.

  The display content displayed on the notification unit 54 includes a display relating to a shooting mode such as a single shot / continuous shooting display, a self-timer display, and the like. In addition, there are displays relating to recording such as compression rate display, recording pixel number display, recording number display, and remaining image number display. In addition, there are displays relating to shooting conditions such as shutter speed display, aperture value display, exposure correction display, flash display, and red-eye reduction display. In addition, macro shooting display, buzzer setting display, battery level display for clock, battery level display, error display, information display with multiple digits, display / removal status display of recording medium 200, communication I / F operation display, date A date / time display is also performed.

  Reference numerals 60, 62, 64, 68, 70, 72, 74, and 76 denote operation means for inputting various operation instructions of the CPU 50, such as a switch, a dial, a touch panel, pointing by line-of-sight detection, and a voice recognition device. Alternatively, it is composed of a plurality of combinations.

  Here, a specific description of these operating means will be given.

  Reference numeral 60 denotes a mode lever that also serves as a power switch (SW), which can be switched between three states: power off (OFF), shooting mode, and playback mode. Reference numeral 62 denotes a mode dial to which various shooting modes set by the user according to the purpose / scene are assigned at the time of shooting. Examples of the shooting mode that can be switched by the mode dial include a fully automatic shooting mode (AUTO), a program shooting mode, a shutter speed priority shooting mode, an aperture priority shooting mode, and a manual shooting mode. In addition, there are a portrait mode, a landscape mode, a night view mode, a color effect mode, a stitch assist mode, and the like.

  Reference numeral 64 denotes a shutter switch (SW), which includes two-stage switches SW1 and SW2. When the shutter button (not shown) is pressed halfway, SW1 is turned on, and an instruction to start operations such as AF processing, AE processing, AWB processing, and EF processing is given. When the shutter button is fully pressed, SW2 is turned on, and the signal read from the image sensor 14 is written into the DRAM 30 as image data via the A / D converter 16 and the signal processing IC 22. Next, the signal processing IC 22 reads the image data from the DRAM 30 in accordance with an instruction from the CPU 50, performs image processing such as color correction, pixel interpolation, and color conversion, then performs compression processing, and stores the processed image data on the recording medium 200. Write.

  Reference numeral 68 denotes a movie SW, which is a switch for instructing start / end of moving image recording.

  Reference numerals 72, 74, and 76 denote a menu key, a set key, and a cross key, respectively. By changing these keys, various settings can be changed during shooting or playback, or a function can be executed while viewing the image display unit 28. Can do. Of these, the cross key 76 is a composite key composed of four directional keys.

  A menu screen is displayed on the image display unit 28 by pressing the menu key 72 once. The displayed menu screen varies depending on the current mode indicated by the mode lever 60 and the mode dial 62. The displayed menu item is selected by using the cross key 76 and the set key 74 is pressed to determine the menu item.

  For example, menu items when the shooting mode is the program shooting mode include a recording pixel size, a compression rate, a recording format, sensitivity, an AF mode, whether to check shooting, image quality tuning parameters, and the like. Further, menu items at the time of reproduction include image erasure (one or all), image protection (protect), image rotation setting, and the like.

  The cross key 76 is also used for other than menu setting. For example, when the shutter speed priority mode is set by the mode dial 62, the shutter speed can be changed using the left / right direction key of the cross key 76. In the playback mode, the left / right direction key of the cross key 76 can be used to advance / return the image.

  Reference numeral 70 is a summary of operation units other than those described above, and includes, for example, a zoom lever, a metering mode switching button, a macro button, an AE lock button, an image display ON / OFF switch for setting ON / OFF of the image display unit 28, and the like. . Items with relatively high use frequency are assigned to the operation unit 70 for items included in the menu.

  A power control unit 80 includes a battery detection circuit, a DC-DC converter, a switch circuit that switches a block to be energized, and the like. The power supply control unit 80 detects the presence / absence of a battery, the type of battery, and the remaining battery level, controls the DC-DC converter based on the detection result and the instruction of the CPU 50, and records the necessary voltage for the necessary period 200 is supplied to each part including 200. Furthermore, the remaining battery level is displayed on the notification unit 54 and the image display unit 28 as necessary.

  Reference numerals 82 and 84 denote connectors, 86 denotes a primary battery such as an alkaline battery or a lithium battery, a secondary battery such as a NiCd battery, NiMH battery, Li-ion battery or Li polymer battery, an AC adapter, or the like.

  A connector 92 connects to a recording medium such as a memory card or a hard disk.

  In this embodiment, the description has been made assuming that one connector for attaching the recording medium is provided. However, the connector for attaching the recording medium may have a single or plural number of systems. Moreover, it is good also as a structure provided with the connector of a different standard. As the connector, it is possible to use a connector compliant with various storage medium standards such as a PCMCIA card or a CF (Compact Flash (registered trademark)) card.

  Reference numeral 94 denotes a microphone for inputting voice during recording. A detection switch (SW) 98 is in a storage state in which a detection function for detecting whether or not the recording medium 200 is attached to the connector 92 and a display portion of the image display unit 28 are stored facing the camera device 100. It includes an image display unit open / close detection function that can detect whether or not. Furthermore, a battery lid open / close detection function for detecting that the battery lid has been opened, a mounting state detection function for the external flash 414, and the like are also included.

  Reference numeral 200 denotes a recording medium such as a memory card or a hard disk. The recording medium 200 includes a recording unit 202 composed of a semiconductor memory, a magnetic disk, and the like, an interface 204 with the camera device 100, and a connector 206 for connecting with the camera device 100.

  Reference numeral 400 denotes an external flash device. In this embodiment, in addition to the built-in flash 48, an external flash device 400 can be mounted later, and TTL light control photography is possible as with the built-in flash. Reference numeral 412 denotes a connector for connecting to the accessory shoe 46 of the camera apparatus 100. Reference numeral 414 denotes an external flash having an AF auxiliary light projecting function and a flash light control function.

  Next, imaging processing in the camera device 100 having the above configuration will be described.

  FIG. 2 is a flowchart showing the operation of the imaging process of the camera device 100 in the present embodiment. The imaging process is executed while the mode lever 60 is set to the imaging mode.

  First, when the mode lever 60 is set to the photographing mode, in step S101, the signal processing IC 22 such as the flag and control variable of the CPU 50 is initialized. By this initialization, the CPU 50 instructs the zoom control circuit 44 to move the photographing lens 10 to the initial position. After initialization, the state shifts to a standby state (step S102). Here, the operation of the camera apparatus 100 in the standby state will be described.

  The light that has passed through the photographing lens 10 passes through the shutter 12 and forms an image on the image sensor 14. At this time, the shutter 12 controls the exposure to some extent by the diaphragm. The subject image formed on the image sensor 14 is photoelectrically converted according to the amount of light, and charges are accumulated. The accumulated charge is read out after a predetermined time has elapsed. At this time, all pixels are not read out, but are read out at a preset frame rate by thinning out (and / or adding and superimposing) in the horizontal direction and the vertical direction. .

  FIG. 4A is a schematic diagram showing an example of addition / decimation at this time, and only 4 horizontal pixels and 16 vertical pixels are shown for easy understanding.

  Reference numeral 401 denotes a pixel on which a color filter is placed, and shows a case where color filters of R (red), G (green), and B (blue) are assigned to each pixel in a Bayer array. Reference numeral 402 denotes a vertical transfer register, 403 denotes a horizontal transfer register, 404 denotes an output circuit, and 405 denotes an output terminal. The signal charge photoelectrically converted by each pixel 401 is sent to the vertical transfer register 402 by a read pulse, and sequentially transferred in the downward direction in the figure by the vertical transfer pulse. The signal charge for one horizontal line transferred from the vertical transfer register 402 to the horizontal transfer register 403 is transferred to the output circuit 404 by a horizontal transfer pulse. Here, it is converted into a voltage, and is output to the outside as a sensor output (analog image signal) from the output terminal 405.

  In the standby mode, the charges of the pixels displayed in the shaded area in the figure are not output to the output circuit 404 but are thinned out, and are actually passed through a charge discharging unit (not shown) connected to the horizontal transfer register 403. Be swept away. In FIG. 4A, lines connected in the vertical transfer register 402 and the horizontal transfer register 403 represent an example of pixels to be added, and R pixels (1, 3 columns) in the 10th and 14th rows. , G pixels (2 and 4 columns) are added with the same color and output. Similarly, the 9th and 13th rows of G pixels (1, 3 columns), B pixels (2, 4 columns), 2nd and 6th rows of R pixels (1, 3 columns) and G pixels (2, 4 columns) (4 columns) G pixels (1, 3 columns) and B pixels (2, 4 columns) in the first and fifth rows are respectively added with the same color and output. As a result, in the standby state, a pixel signal obtained by adding two pixels horizontally, adding two pixels vertically, and decimating 1/2 is output. Therefore, it is possible to read out at a frame rate eight times that of reading out all pixels.

  The analog image signal read out and processed by the pre-processing circuit 15 as described above is sent to the A / D converter 16 where it is converted into digital image data and sent to the signal processing IC 22 via the system bus. Transferred.

  Since image data is not recorded in the standby state, the acquired image data is used as an image for an electronic viewfinder that is sequentially displayed on the image display unit 28. Therefore, the signal processing IC 22 performs resizing processing after performing horizontal and vertical filter processing suitable for moving image shooting, aperture correction processing, gamma processing, and the like. In the resizing process, the image is resized to a predetermined pixel size, for example, a VGA (horizontal 640 pixels, vertical 480 lines) size, and transferred to the DRAM 30. The image data on the DRAM 30 is transferred to the image display unit 28 and displayed as a through image.

  On the other hand, while displaying as a through image, the signal processing IC 22 continuously performs AF, AE, and AWB on the basis of the digital image data sent from the A / D converter 16 according to the position / situation of the subject. Calculate the value. Based on this result, the CPU 50 drives and controls the photographing lens 10, the aperture of the shutter 12, and the image sensor 14. In the standby state, the focus state and brightness of the through image displayed on the image display unit 28 are gradually focused so as to be used in moving image shooting by a known method so as not to change suddenly. Or change the brightness.

  Next, in step S103, the states of the shutter switch 64 and the movie switch 68 are checked. If neither is pressed, the process returns to step S102 and the above-described processing in the standby state is repeated.

If the shutter switch 64 is operated and SW1 is in the ON state, the process proceeds to step S121, AF, AE, and AWB for still images are executed, and the photographing lens 10 is moved to the in-focus position. AF for a still image to be performed here, AE, AWB, since it is have use a known method suitable for still image shooting, detailed description thereof will be omitted. Note that, unlike the above-described AF operation in the standby state, control is performed so that the in-focus state can be obtained as quickly as possible.

  Next, the state of the shutter switch 64 is checked (step S122). If there is no change (only SW1 is ON), the process returns to step S121. If SW1 is OFF, the process returns to step S102 and returns to the standby state described above. If SW2 is ON, still image shooting is performed in step S123. The still image shooting performed here will be described later in detail with reference to FIG. When the still image shooting is finished, the process returns to step S102 to return to the standby state described above.

  On the other hand, if the movie switch 68 is pressed in step S103, the process proceeds to step S104, and the first thinning drive is started. Here, the first thinning driving is the same as the driving described with reference to FIG. 4A described above in the standby state described above. As described above, by driving as shown in FIG. 4A, it is possible to read out at a frame rate eight times that of reading out all pixels. The CPU 50 instructs the timing generation circuit 18, the image sensor 14, and the pre-processing circuit 15 to switch to the first thinning drive via the signal processing IC 22.

  Next, in step S105, moving image recording is performed. Here, the details of the moving image recording process will be described.

  The light that has passed through the photographing lens 10 passes through the shutter 12 and forms an image on the image sensor 14. At this time, the shutter 12 controls the exposure to some extent by the diaphragm. The subject image formed on the image sensor 14 is photoelectrically converted according to the amount of light, and charges are accumulated. Then, the accumulated charge is read out by the first thinning drive.

  The read analog image signal is sent to the A / D converter 16, converted into digital image data, and transferred to the signal processing IC 22 via the system bus.

  In the signal processing IC 22, horizontal and vertical filter processing suitable for moving image shooting, aperture correction processing, gamma processing, and the like are performed, and then resizing processing is performed. In the resizing process, the image is resized to a predetermined pixel size, for example, a VGA (horizontal 640 pixels, vertical 480 lines) size, and transferred to the DRAM 30.

  The signal processing IC 22 converts the image data on the DRAM 30 into, for example, JPEG data using a compression / decompression circuit. At the same time, the sound is captured by the microphone 94, and the captured sound is converted by the CPU 50 into, for example, WAVE format sound data. The CPU 50 adds a header to these image JPEG data and audio WAVE data to generate a moving image file, for example, in the AVI data format, and records the generated moving image file on the recording medium 200 via the connector 92.

  In the data structure of the AVI file, the arrangement of image data and audio data is managed by the header at the top of the file. For example, audio data for 1 second (44.1 KHz sampling, 16-bit stereo in the case of 16-bit stereo) is placed after the header, and image JPEG data for 1 second (30 frames in the case of 30 fps) is further placed. Audio data and image data are alternately arranged every second.

  Therefore, when creating a moving image file, the DRAM 30 secures an image buffer area for buffering still image JPEG data and an audio buffer area for buffering audio data. Then, the generated video data and audio data are accumulated in the reserved area, and the image data and audio data are collected into AVI format data and written to the AVI buffer area on the DRAM 30 in units of one second. Data stored in the AVI buffer area is sequentially written to the recording medium 200 as a file.

In the above example, the case where the image data compression method is the JPEG method and the audio data is converted to the WAVE format has been described. However, the present invention is not limited to this, and a known compression method and format may be used. Needless to say. Furthermore, video files, in addition to the AVI file format, it is of course possible to Ru with a known file format.

  As described above, moving image recording is collectively performed in AVI format data, while through display on the image display unit 28 is also performed. Image data resized to a predetermined pixel size, for example, VGA (horizontal 640 pixels, vertical 480 lines) size in the signal processing IC 22 is transferred to the DRAM 30, and the image data on the DRAM 30 is transferred to the image display unit 28. Displayed as a through image. Thereby, the user can confirm the moving image being recorded.

Next, in step S106, AF, AE, and AWB are continuously performed for moving image recording, but are performed by a known method so that the focused state and brightness of the moving image to be recorded do not change abruptly. Gradually focus or change the brightness .

  Next, the state of the shutter switch 64 and the movie switch 68 is checked (step S107). If neither is pressed, the process returns to step S105 to repeat the moving image recording and AF, AE, and AWB. If the movie switch 68 is pressed, the moving image recording is terminated, the process returns to step S102, and the above-described standby state is entered.

  On the other hand, when the shutter switch 64 is pressed and SW1 is ON in step S107, the process proceeds to step S108, and the charge reading drive of the image sensor 14 is switched to the second thinning drive.

  FIG. 4B is a schematic diagram showing an example of the second thinning drive, and only the horizontal 4 pixels and the vertical 16 pixels are shown for easy understanding. In addition, the same reference number is attached | subjected to the same structure as Fig.4 (a), and description is abbreviate | omitted.

  In FIG. 4B, lines connected in the vertical transfer register 402 and the horizontal transfer register 403 represent an example of added pixels, and R pixels (1, 3 columns) in the 12th and 16th rows. , G pixels (2 and 4 columns) are added with the same color and output. Similarly, the G pixels (1, 3 columns) and B pixels (2, 4 columns) in the third row and the seventh row are added with the same color and output. As can be seen from the fact that there are more shaded portions than in FIG. 4A, the difference from the first thinning drive shown in FIG. 4A is the thinning amount in the vertical direction. Is vertical ¼ thinning. Since the thinning amount is doubled, the frame rate can also be read out at a speed twice as high as that in the first thinning driving shown in FIG.

  Next, in step S109, moving image recording and through image display are performed using the image data obtained by the second thinning driving. In the moving image recording process in step S109, since the number of pixels to be read is smaller than that in the first thinning drive, the signal processing IC 22 performs resizing processing such as interpolation and thinning so that the number of pixels is suitable for moving image recording. Write the resized image data. The subsequent processing is the same as the moving image recording processing and the through image display processing described in step S105, and thus description thereof is omitted. In addition, since reading is performed at a frame rate twice that of the first thinning drive, image data processed every other frame is recorded here.

In step S109, along with the moving image recording process, AF, AE, and AWB processes for still image shooting are performed using the image data obtained by the second thinning drive. As described above, since the second thinning drive can operate at a high frame rate, it is possible to perform AF control at a higher speed and finish the preparation for still image shooting. In the AF control performed at this time, the AF control method during moving image recording may be continuously focused gradually, or may be controlled so as to focus as quickly as possible for still image shooting. Even in the former case, since readout is performed at a frame rate twice that in the first thinning drive, focusing can be completed at twice the speed.

  As a result, the shutter time lag from when the shutter switch 64 is pressed during moving image shooting to when still image shooting is performed can be shortened, and even during AF, AE, and AWB processing for still image shooting, Recording can be continued.

  Next, the state of the shutter switch 64 is checked (step S110). If there is no change (only SW1 is ON), the process returns to step 109 to continue the moving image recording and AF, AE, and AWB processing by the second thinning drive. If SW1 is OFF, the process returns to step S104 to switch to the first thinning drive, and the above-described moving image recording is repeated. On the other hand, when SW2 is turned on, the moving image recording is interrupted and still image shooting is performed (step S111). The still image shooting process performed here will be described later in detail with reference to FIG. When the still image shooting is completed, the process returns to step S104 to switch to the first thinning drive, and the above-described moving image recording is repeated.

  In the above flow, control is performed so that the second thinning drive is continued until SW2 is pressed or SW1 is turned OFF after SW1 is turned ON during moving image recording. However, after the AF process is finished, the first thinning drive may be changed. By doing so, it is possible to shorten the period during which the moving image resolution is lowered when SW1 is ON.

  Next, the still image shooting process performed in steps S111 and S123 will be described with reference to the flowchart of FIG.

  First, based on the photometric result obtained in step S109 or S121 in FIG. 2, settings such as shutter speed, imaging output gain, flash emission, etc. at the time of shooting are determined (step S301). Further, the through display on the image display unit 28 is stopped (step S302). Next, DRAM write setting for temporarily storing RAW data in the DRAM 30 is performed (step S303). At this time, the setting of writing to the DRAM 30 is not performed continuously on the memory, but is performed on the DMA controller in the signal processing IC 22 so that writing is performed every several lines in accordance with a multi-field reading method. Of course, it is possible to read by progressive scan, and in this case, the DMA controller is set to sequentially write to the DRAM 30.

  Next, an electronic shutter stop command is issued to the timing generation circuit 18 to start exposure, and the timing for closing the shutter 12 is set in the CPU built-in timer according to the determined shutter speed (step S304). This CPU built-in timer is designed to output a pulse for fully closing the shutter 12 when a specified time has elapsed. Next, it waits for the shutter 12 to close (step S305). When the shutter 12 is closed, a write start command is issued for each field in the DRAM area set in step S303. At the same time, the timing generation circuit 18 is instructed to sequentially read out the imaging data of each field from the imaging device 14 (step S306). The read signal is converted into a digital signal (RAW data) by the A / D converter 16 and transferred to the DRAM 30 via the bus.

  When reading and writing are completed, post-shooting processing is performed to open the shutter 12 and restart the electronic shutter operation so that the next shooting can be performed quickly (step S307).

  Thereafter, the image data is read in order, WB calculation is performed, WB coefficients to be multiplied by the output of each color are calculated (step S308), and color correction is performed based on the WB coefficients obtained in the preprocessing (step S309). .

  Next, development and compression processing for converting into image data to be finally recorded is performed. In this development processing, first, RAW data is read from the DRAM 30 and transferred to the signal processing IC 22. The signal processing IC 22 performs horizontal / vertical filter processing, aperture correction processing, gamma processing, and the like suitable for still image shooting, and transfers them to the compression / decompression circuit. The compression / decompression circuit converts the YUV data into JPEG data and writes it back to the DRAM 30 (step S310). The development process is from the RAW data reading from the DRAM 30 until the JPEG data is written back to the DRAM 30. At this time, the signal processing IC 22 in the middle of the development processing resizes the YUV data, resizes it to about VGA size for review image display, and writes it back to the DRAM 30.

  When the above-described development processing is completed, the VGA size image data (YUV data) stored in the DRAM 30 is converted into a display image and stored in the DRAM 30 in order to display a review image for confirming the captured image. The display image data is read out by the signal processing IC 22 at a predetermined rate, internally D / A converted, and then output to the image display unit 28 to display a confirmation image (step S311). In step S310, the compressed image data stored in the DRAM 30 is written to the recording medium 200 (step S312), and the still image shooting process is terminated.

  Next, referring to FIG. 5, for a sequence in which still image shooting is performed during moving image recording at VGA 30 fps, taking as an example a digital camera having an image sensor of 5 million pixels that can be driven as shown in FIG. explain. With this imaging device, it is possible to capture still images with a pixel size of up to 2592 × 1944. Note that the description of the recording sequence of audio that is recorded at the same time as the moving image recording is omitted.

  In the T1 period, the live view display is continued while recording the moving image. In this state, the shutter 12 is open. In this T1 period, since the image sensor 14 is driven by the first thinning driving shown in FIG. 4A described above, the horizontal readout is 2-pixel addition and the vertical 1/2 reduction is 2-pixel addition. The number of effective pixels is 1296 × 486. The read pixel signal is developed in real time and resized to the VGA size (640 × 480) in the signal processing IC 22 and stored in the DRAM 30.

  The image data temporarily stored in the DRAM 30 is transferred to the image display unit 28 and displayed through, and also sent to the signal processing IC 22 to be converted into JPEG data and recorded on the recording medium 200. During this period, the frame rates for reading, displaying, and recording are all 30 fps, which coincide.

  Next, when SW1 is pressed in this state, in order to perform an AF operation for still image shooting, switching to the second thinning driving shown in FIG. Read. The period during which SW1 is pressed is T2. In this T2 period, since the image sensor 14 is driven by the second thinning driving shown in FIG. 4B described above, the horizontal pixel addition is two pixels and the vertical pixel thinning is two pixel addition. The number of effective pixels is 1296 × 243. Then, development processing and resizing to VGA size are performed on the read pixel signal (here, horizontal signal thinning and vertical signal interpolation processing are performed. Thereby, moving image recording and through display are interrupted. Note that since reading from the image sensor 14 is performed not for partial reading but for the entire region, there is no change in the angle of view before and after SW1 is pressed, and even after SW1 is pressed. There are merits that there is no unnaturalness in display and video recording, and framing is easy.

  However, while the imaging clock rate was 30 fps in the T1 period, the vertical thinning amount is doubled in the T2 period, so that the operation is performed at 60 fps. On the other hand, since the moving image recording format is specified here as 30 fps, it is necessary to thin out the images in the time series direction. Here, in FIG. 5, the image of the shaded portion of the vertical period in the T2 period is not recorded, but the other portions are recorded, thereby intentionally dropping frames, and recording / displaying at 30 fps.

  In this embodiment, the recording and display frame rates are the same, but they are not necessarily the same. For example, the recording may be 30 fps and the display may be 60 fps. In this case, there is an advantage that the through display while SW1 is pressed becomes smooth and the display delay is small.

  If SW2 is further pressed in this state, it is determined that still image shooting is performed, moving image recording is temporarily interrupted, and the above-described still image shooting operation is performed. During exposure and readout of still images, a single color image such as a black image is displayed on the image display unit 28. After still image development processing, an image of 2592 × 1944 pixels, which is the size for still images, and an image of VGA (640 × 480 pixels) size recorded in a moving image file are generated. Using the generated VGA size image, the review image is transferred to the image display unit 28 and displayed.

  When the still image shooting is completed, the first decimation drive is resumed, and the interrupted moving image recording is resumed (T4).

  In the example illustrated in FIG. 5, the case where the angle of view at the time of moving image shooting corresponds to the entire area of the image sensor 14 has been described. However, when the angle of view is narrowed by electronic zoom, All the pixels included in the area corresponding to the angle of view may be read out.

  Further, when the camera device 100 can change the resolution at the time of still image shooting, it is not limited to the all-pixel reading drive, and it may be driven so as to perform thinning or addition according to the designated resolution.

  As described above, according to the present embodiment, it is possible to select an image sensor driving method suitable for AF operation even when performing still image AF operation during moving image recording. Can be improved and the time lag can be shortened. In addition, since the moving image recording and display can be continued even during the AF operation period when the still image shooting is instructed during moving image recording, the interruption period of the moving image recording can be minimized.

  In the above embodiment, the first and second thinning-out driving is described as being driven as shown in FIGS. 4A and 4B, respectively. However, the present invention is not limited to this. Absent. The number of pixels of the image sensor, the reading speed, and the moving image standard to be applied can be changed as appropriate. In this case, reading is performed at a higher frame rate during the second thinning driving than during the first thinning driving. Can be done. In addition, the frame rate in the second thinning drive is not limited to a frame rate that is twice that of the first thinning drive, and may be a frame rate that is three times or more depending on the driving speed of the image sensor. In that case, the frames may be thinned out so that the frame rate conforms to the moving image standard applied by the camera device.

  In the above embodiment, the image sensor is read by the first thinning drive even in the standby state. However, the read driving is different from the first thinning driving depending on the number of pixels of the image display unit 28. May be.

  In the above-described embodiment, the case where shooting is performed using the EVF function by the image display unit 28 has been described. However, shooting can be performed using the optical viewfinder 11 without using the EVF function. Even in that case, the method described above can be applied when still image shooting is instructed during moving image recording, the AF operation for still images is accelerated, and moving image recording is performed during the AF operation. Can do.

It is a block diagram which shows the structure of the digital still movie camera system in embodiment of this invention. It is a flowchart which shows the imaging | photography process in embodiment of this invention. It is a flowchart which shows the still image imaging | photography process in embodiment of this invention. It is a schematic diagram for demonstrating the thinning drive in embodiment of this invention. It is a conceptual diagram which shows the still image shooting sequence during moving image recording.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10: Shooting lens 12: Shutter 14: Image pick-up element 15: Pre-processing circuit 16: A / D converter 18: Timing generation circuit 22: Signal processing IC
28: Image display unit 30: DRAM
50: CPU
52: Flash memory 54: Notification section 60: Mode lever 62: Mode dial 64: Shutter switch 68: Movie switch 70: Operation section 72: Menu key 74: Set key 76: Cross key 80: Power control section 86: Power supply 94: Microphone 98: Detection switch 100: Digital still movie camera device 200: Recording medium

Claims (7)

An image sensor that outputs image data obtained by photoelectric conversion of incident light; and
Drive control means for driving the image sensor;
Focus adjusting means for performing focus adjustment processing based on image data output from the image sensor;
Recording means for recording image data output from the image sensor;
When the recording of the moving image is instructed, the image data obtained by driving the imaging element by the first driving method by the drive control unit is recorded by the recording unit, and a still image is shot during the moving image recording. When instructed, the image pickup device is driven to be thinned out by the drive control means in a second drive method having the same angle of view as the first drive method and a frame rate higher than that of the first drive method. The image data obtained in this way is converted into the number of pixels corresponding to the image data obtained by the first driving method and recorded by the recording means , and the image data obtained by the second driving method is recorded on the image data obtained by the second driving method. Based on this, the focus adjustment unit performs focus adjustment processing for still image shooting, and after focusing, the image pickup device is driven by the drive control unit by a third drive method having a higher resolution than the first drive method. Obtained Imaging apparatus characterized by a control means for controlling the image data to record by the recording means. It said drive control means, in the second driving method, an imaging apparatus according to claim 1, characterized in that to read the image data at multiple frame rates of the first driving method. During driving in the second driving method by the drive control means, said recording means imaging apparatus according to claim 1 or 2, characterized in that the recording while thinning out the frames. Image processing means for processing the image data obtained from the image sensor into image data compliant with a predetermined standard while being driven by the first and second driving methods by the drive control means;
Said recording means, wherein during the driving by the first and second driving methods, imaging according to any one of claims 1 to 3, characterized in that for recording the image data processed by said image processing means apparatus. In the first driving method, the drive control unit performs thinning readout without reading image data of some of the pixels of the image sensor, and image data of pixels of the image sensor for a plurality of pixels. Read out image data from the image sensor by performing at least one of addition reading that is added and read out one by one, and in the second driving method, thinning-out reading that thins out more pixels than in the first driving method, and according to any one of claims 1 to 4, characterized in that reading the image data from the imaging device performs at least one of addition readout for adding image data of a number of pixels than the first driving method Imaging device. It said drive control means, in the third driving method, in claim 5, characterized in that reading out each image data from the entire pixel area of the image pickup elements corresponding to the same angle as the first driving method The imaging device described. Said control means, after recording the image data obtained in the third driving method, according to any one of claims 1 to 6, wherein the controller controls so as to return to the first driving method Imaging device.

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