JP2010011124A - Image pickup apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image pickup apparatus that avoids an unnatural output image caused by interfusing a still image in a moving image. <P>SOLUTION: Whether a user of a video camera can discern an unnatural motion or the discernable unnatural motion is permissible is evaluated based on an taken image so as to make change between mixing of still image shooting driving and maintaining of motion image shooting driving. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an imaging apparatus.

  2. Description of the Related Art Recent imaging devices such as video cameras perform moving image shooting and recording in accordance with the television standard, and still image shooting and recording with more pixels than the television standard. In addition, although the number of pixels of the image sensor (image sensor) is increasing, in capturing and recording moving images, it is necessary to read a two-dimensional image from the image sensor at least in the field period in accordance with the television standard. For this reason, in shooting and recording of moving images, the number of read pixels from the image sensor is reduced by cut-out reading, thinning-out reading, pixel addition reading, and the like, and the number of read channels is increased or the reading speed is increased. However, an increase in the number of readout channels and an increase in readout speed deteriorate the device cost and power consumption. Therefore, a device is devised to reduce the number of readout pixels from the image sensor during moving image shooting. In some cases, the video camera body is provided with a switch for switching between moving image shooting and still image shooting, a moving image shooting trigger, and a still image shooting trigger.

On the other hand, in order to simplify the operation and not miss a photo opportunity, switching between moving image shooting and still image shooting is eliminated and still image shooting is performed during moving image shooting (see, for example, Patent Document 1). . This publication captures and records a still image at a field timing that is continuous with a field timing for generating a moving image, and compensates for a field period in which the still image is missing by converting the still image into a moving image format.
JP 2001-352484 A

  However, in Patent Document 1, if a moving image that is missing during still image shooting is converted from a still image and compensated, the motion of the moving image becomes unnatural when shooting a still image while the subject continues to move. There is a problem of becoming.

  Therefore. An object of the present invention is to provide an imaging apparatus that prevents a moving image from being mixed with a still image and an output moving image from becoming unnatural.

  An image pickup apparatus according to an aspect of the present invention includes an image pickup device that picks up an image of a subject, and a first drive signal that drives the image pickup device so as to convert an image picked up by the image pickup device into an electric signal by interlace scanning. A first drive circuit that generates, a second drive circuit that generates a second drive signal for driving the image sensor so as to progressively scan an image captured by the image sensor and convert the image into an electrical signal; A moving image signal processing circuit that outputs a first video signal based on interlace scanning by performing signal processing for moving images on the output, and represents a moving image state based on the first video signal of the moving image signal processing circuit Based on the evaluation value generation unit that generates an evaluation value and the evaluation value of the evaluation value generation unit, it is determined that the imaging device should be driven for moving images when the movement of the subject is detected in the moving image. And an image evaluation unit that determines that the image sensor should be driven for a still image when the motion of the subject is not detected in the moving image, and the image evaluation unit drives the image sensor for a moving image. If it is determined that it should be, a first state signal indicating that still image recording has been performed during movie shooting standby, movie shooting, or movie shooting is generated. A selection circuit that generates a second state signal indicating that image recording has been performed, and the first drive circuit is selected based on the first state signal of the selection circuit, and based on the second state signal of the selection circuit And a first selector for selecting the second driving circuit.

  According to the present invention, it is possible to provide an imaging device that prevents a moving image from being mixed with a still image and an output moving image from becoming unnatural.

  FIG. 1 is a block diagram of the video camera (imaging device) of this embodiment.

  An image is formed on an image sensor (image sensor) 2 through the lens 1, and the image sensor 2 images the subject and outputs a video output signal S2. In the image sensor 2, either the vertical / horizontal synchronization signal S3 output from the image sensor drive circuit I3 or the vertical / horizontal synchronization signal S4 output from the image sensor drive circuit II4 is output from the selector 5 (first selector). Selected and supplied by. The image pickup device drive circuit I3 generates a first vertical / horizontal synchronization signal S3 (first drive signal) for driving the image pickup device 2 so as to interlace scan an image picked up by the image pickup device 2 and convert it into an electric signal. It is a drive circuit. The image pickup device drive circuit II4 generates a vertical / horizontal synchronization signal S4 (second drive signal) for driving the image pickup device 2 so as to progressively scan the image picked up by the image pickup device 2 and convert it into an electrical signal. Circuit. The video output signal S2 is interlaced when the vertical / horizontal synchronization signal S3 is supplied to the image sensor 2, and is progressively scanned when the vertical / horizontal synchronization signal S4 is supplied to the image sensor 2. Become.

  The moving image signal processing circuit 6 uses the video output signal S2 of the image sensor 2 and the output signal S14 of the selection circuit 14 as input signals, performs video signal processing on the video output signal S2 of the image sensor 2, and performs interlace scanning. A moving image signal (first video signal) based thereon is output as an output signal S6.

  The moving image recording processing circuit 7 receives the output signal S6 of the moving image signal processing circuit 6 and the output signal S131 of the CPU 13 as input signals, and outputs the output signal S6 of the moving image signal processing circuit 6 to the moving image recording medium 17 during moving image recording. Record and do nothing when it is in any other state.

  The moving image display processing circuit 8 uses the output signal S6 of the moving image signal processing circuit 6 as an input signal, and performs a process of displaying the output signal S6 of the moving image signal processing circuit 6 on the display unit 18 attached to the imaging apparatus. The moving image display processing circuit 8 performs processing for displaying the output signal S6 of the moving image signal processing circuit 6 regardless of which of the image sensor driving circuits I3 and II4 is selected by the selector 5.

  The scanning line interpolation circuit 9 uses the output signal S6 of the moving image signal processing circuit 6 as an input signal. The scanning line interpolation circuit 9 interpolates the scanning line to the output signal S6 of the moving image signal processing circuit 6 which is an interlaced scanning video signal (first video signal), and converts it to a progressive scanning video signal (third video signal). The output signal S9 is output.

  The evaluation value generation unit 15 uses the output signal S6 of the moving image signal processing circuit 6 as an input signal, and generates an evaluation value S15 representing the state of the captured moving image based on the input signal.

  The image evaluation unit 16 uses the evaluation value S15 of the evaluation value generation unit 15 as an input signal, and generates an image sensor drive determination signal S16 representing a moving image drive determination and a still image drive determination based on the input value. The “moving image drive determination” is a determination that the image sensor 2 should be driven for moving images, and the “still image drive determination” is a determination that the image sensor 2 should be driven for a still image. Specifically, the image evaluation unit 16 determines (or evaluates) that the image sensor 2 should be driven for a moving image when a movement of a subject in a certain direction is detected in a moving image. The image evaluation unit 16 determines that the image sensor 2 should be driven for a still image when the movement of the subject is not detected in the moving image.

  The still image signal processing circuit 10 uses the output signal S2 of the image sensor 2 as an input signal, performs signal processing for the still image on this, and outputs a video signal based on progressive scanning as an output signal S10 (second video signal). To do.

  The selector 11 (second selector) receives the output signal S9 from the scanning line interpolation circuit 9, the output signal S10 from the still image signal processing circuit 10, and the output signal S14 from the selection circuit 14 as input signals. The selector 11 selects either the output signal S9 of the scanning line interpolation circuit 9 or the output signal S10 of the still image signal processing circuit 10 based on the output signal S14 of the selection circuit 14, and outputs it as the output signal S11. Specifically, the selector 11 selects the third video signal of the scanning line interpolation circuit 9 in response to the signal 0 of the selection circuit 14 and responds to the signal 1 of the selection circuit 14 in the still image signal processing circuit 10. A second video signal is selected.

  The still image recording processing circuit 12 uses the output signal S11 of the selector 11 and the output signal S132 of the CPU 13 as input signals. The still image recording processing circuit 12 records the output signal S11 of the selector 11 on the still image recording medium 19 when the output signal S132 of the CPU 13 is in a still image recording state, and performs any processing in other states. Absent.

  The CPU (control unit) 13 outputs a signal for determining whether or not moving image recording is being performed as an output signal S131, and outputs a signal for determining whether or not still image recording has been performed as an output signal S132. . The CPU 13 determines whether a moving image is being recorded or whether a still image has been recorded based on an input to the operation unit 20. The operation unit 20 includes a relief button, an operation dial, various buttons, a switch, and a lever, and notifies the CPU 13 when the photographer performs moving image recording or still image recording.

  The selection circuit 14 receives the output signal S132 of the CPU 13 and the determination signal S16 for driving the imaging device as input signals, and outputs a synchronization signal to be supplied to the imaging device 2 and an output signal S14 that determines the operation of the moving image signal processing circuit 6. When the image evaluation unit 16 determines that the image sensor 2 should be driven for moving images, the selection circuit 14 indicates that still image recording has been performed during movie shooting standby, movie shooting, or movie shooting. A signal 0 (first state signal) is generated. The selection circuit 14 generates a signal 0 (second state signal) indicating that still image recording has been performed when the output signal S132 of the CPU 13 indicates that still image recording has been performed.

  The selector 5 selects the image sensor driving circuit I3 based on the signal 0 (first state signal) of the selection circuit 14, and selects the image sensor driving circuit II4 based on the signal 1 (second state signal) of the selection circuit 14. To do. As a result, it is possible to prevent a moving image from being mixed with a still image and an output moving image from becoming unnatural.

  FIG. 2 is a circuit diagram showing details of the structure of the image pickup device 2. For the sake of simplicity, only 16 pixels of 4 vertical rows and 4 horizontal columns are displayed, but in reality, 1080 vertical rows and 1920 horizontal columns are displayed. There are pixels.

  In FIG. 2, 201 is a photoelectric conversion pixel unit, 202 is a photodiode, 203 is a pixel readout switch, and 204 is a charge-voltage conversion buffer. As described above, the imaging device 2 has a plurality of photoelectric conversion elements. Reference numerals 205-1 to 205-4 denote row selection lines for the first to fourth rows, and illustration of the row selection lines for the fifth to 1080th rows is omitted. Reference numerals 206-1 to 206-4 denote column signal lines from the first column to the fourth column, and column signal lines from the fifth column to the 1920 column are omitted. Reference numerals 207-1 to 207-4 denote column selection switches from the first column to the fourth column, and illustration of the column selection switches from the fifth column to the 1920 column is omitted. Reference numerals 208-1 to 208-4 denote selection switches for the first horizontal capacitor group in the first to fourth columns, and illustration of the selection switches in the fifth to 1920 columns is omitted. Reference numerals 209-1 to 209-4 denote selection switches for the second horizontal capacitor group in the first to fourth columns, and illustration of the selection switches in the fifth to 1920 columns is omitted. Reference numerals 210-1 to 210-4 denote first horizontal capacitor groups in the first to fourth columns, and illustration of the first horizontal capacitor groups in the fifth to 1920 columns is omitted. 211-1 to 211-4 are second horizontal capacitor groups in the first to fourth columns, and the second horizontal capacitor groups in the fifth to 1920 columns are not shown. Reference numerals 212-1 to 212-4 denote horizontal drive switches from the first column to the fourth column, and illustrations of horizontal drive switches from the fifth column to the 1920 column are omitted. Reference numeral 213 denotes a vertical scanning circuit, and 214 denotes a horizontal scanning circuit. Reference numeral 215 denotes a vertical synchronization signal input that is input from the image sensor driving circuit I3 or the image sensor driving circuit II4 via the selector 5. Reference numeral 216 denotes a horizontal synchronization signal input input from the image sensor driving circuit I3 or the image sensor driving circuit II4 via the selector 5. Reference numeral 217 denotes an output signal buffer, and 218 denotes a video signal output.

  The image sensor 2 operates as follows based on a synchronization signal provided via the selector 5 by the image sensor drive circuit I3 or the image sensor drive circuit II4. 3 to 6 are timing charts of the image sensor 2.

  First, when the selector 5 selects the image sensor driving circuit I3, as shown in FIG. 3, a vertical synchronizing signal with a field driving period of 16.7 msec = (1 / 59.96 sec) is given from the vertical synchronizing signal input 215. It is done. Further, a horizontal synchronization signal having an interval of 29.78 μsec = (16.7 msec / 560H) is given from the horizontal synchronization signal input 216. Thus, vertical driving is performed for the vertical blanking period 20H and the vertical effective period 540H.

  In the first field of FIG. 3, the vertical scanning circuit 213 scans the row selection line by two rows per horizontal synchronization period after the vertical blanking period. That is, the row selection lines 205-1 and 2 of the first row and the second row in FIG. 3 are followed by the row selection lines 205-3 and 4 of the third and fourth rows, and the rows of the 1079th and 1080th rows. Scan with selection line.

  Detailed operations of the row selection line and the horizontal scanning circuit 214 are shown in FIG. When the horizontal synchronization signal is asserted, the row selection line 205-1 of the first row is asserted at the subsequent times t1 to t2, and 1920 photoelectric conversion elements connected to the row selection line 205-1 of the first row. Are simultaneously read out to 1920 column signal lines.

  As shown in FIG. 4, from time t1 to time t2, the column selection switch 207 and the selection switch 208 of the first horizontal capacitor group are also asserted simultaneously. In FIG. 4, 207 represents “207-1”, “207-2”. Similarly, 208 represents “208-1”, “208-2”. 209 represents “209-1”, “209-2”... Photoelectric conversion signals from 1920 photoelectric conversion elements connected to the first row selection line 205-1 are accumulated in the first horizontal capacitor group (210-1 or the like).

  Next, at time t3 to t4, the second row selection line 205-2 is asserted, and the photoelectric conversion signals of the photoelectric conversion elements connected to the second row selection line 205-2 are 1920 column signals. Read to line. From time t3 to t4, the column selection switch 207 and the selection switch 209 of the second horizontal capacitor group are also asserted simultaneously. For this reason, photoelectric conversion signals from 1920 photoelectric conversion elements connected to the second row selection line 205-2 are accumulated in the second horizontal capacitor group (211-1 or the like).

  Next, at time t5, the selection switch 208 for the first horizontal capacitor group and the selection switch 209 for the second horizontal capacitor group are both asserted. As a result, the first row photoelectric conversion signals and the second row photoelectric conversion signals held in the first horizontal capacitor group (210-1 and the like) and the second horizontal capacitor group (211-1 and the like) are averaged. It becomes.

  Next, at time t6 to t7, horizontal drive switches (212-1, etc.) for 1920 columns are asserted in order. For this reason, a video signal obtained by vertically averaging 1920 photoelectric conversion element outputs in the first and second rows passes through the output signal buffer 217 and is output from the video signal output 218. After time t8, the operation is performed in the next horizontal synchronization period (average reading of the photoelectric conversion signal in the third row and the photoelectric conversion signal in the fourth row).

  In the second field of FIG. 3, the vertical scanning circuit 213 scans the row selection lines by two rows per horizontal synchronization period after the vertical blanking period. That is, the second and third row selection lines 205-2 and 3, the fourth row selection line 205-4, the fifth row selection line, the 1080th row and the 1081th row selection line ( Note that the row selection line of the 1081st row is a dummy). As a result, the combination of averaging operations for two adjacent vertical lines is changed. Thereby, the second field is interlaced with the first field.

  When the selector 5 selects the image sensor driving circuit II4, as shown in FIG. 5, the vertical synchronization at an interval of 33.4 msec = (1 / 29.97 sec), which is twice the field driving period, from the vertical synchronization signal input 215. A signal is given. Further, a horizontal synchronizing signal having an interval of 29.78 μsec = (29.97 msec / 1120H) is given from the horizontal synchronizing signal input 216. Thus, vertical driving is performed for the vertical blanking period 20H, the vertical effective period 1080H, and the dummy period 20H.

  In the vertical scanning circuit 213, after the vertical blanking period, the row selection lines are asserted one row at a time in one horizontal synchronization period, and the pixels are sequentially scanned up to the 1080th row selection line, and all the pixels are driven in a period of two fields. The

  Detailed operations of the row selection line and the horizontal scanning circuit 214 are shown in FIG. When the horizontal synchronization signal is asserted, the row selection line 205-1 of the first row is asserted at subsequent times t1 to t2, and the column selection switch 207 and the selection switch 208 of the first horizontal capacitor group are simultaneously asserted. . As a result, photoelectric conversion signals from 1920 photoelectric conversion elements connected to the first row selection line 205-1 are accumulated in the first horizontal capacitor group (210-1 and the like).

  At subsequent times t3 to t4 and time t5, nothing is asserted, so no operation is performed.

  Next, from time t6 to t7, horizontal drive switches (212-1, etc.) for 1920 columns are sequentially asserted. Therefore, 1920 photoelectric conversion signals in the first row pass through the output signal buffer 217 and are output from the video signal output 218. After time t8, the next horizontal synchronization period is set (reading of photoelectric conversion signals in the second row). As a result, the video output is obtained by progressively reading all the pixels.

  As described above, when the output signal S5 of the selector 5 is the vertical / horizontal synchronization signal S3 output from the image sensor driving circuit I3, the image sensor 2 outputs the video signal of interlaced scanning in the field cycle as the output signal S2. Output as. On the other hand, when the output signal S5 of the selector 5 is the vertical / horizontal synchronization signal S4 output from the image sensor driving circuit II4, the image sensor 2 outputs a video signal of progressive scanning of the frame period as the output signal S2.

  When the output signal S14 of the selection circuit 14 is 0, it means that the still image recording process has been performed during moving image shooting standby, during moving image shooting, or during moving image shooting. In this case, the selector 5 outputs the vertical / horizontal synchronization signal S3 output from the image sensor driving circuit I3 as the output signal S5 so that the image sensor 2 performs interlaced scanning in the field cycle. On the other hand, when the output signal S14 of the selection circuit 14 is 1, it means that still image shooting has been performed. In this case, the selector 5 outputs the vertical / horizontal synchronization signal S4 output from the image sensor driving circuit II4 as the output signal S5 so that the image sensor 2 performs progressive scanning of the frame period.

  The moving image signal processing circuit 6 uses the video output signal S2 of the image sensor 2 and the output signal S14 of the selection circuit 14 as input signals. When the output signal S14 of the selection circuit 14 is 0, the moving image signal processing circuit 6 performs processing such as moving image aperture correction, gamma correction, luminance adjustment, white balance, and the like, and resizes it to the angle of view of the moving image recording format. Processing is performed and output as an output signal S6. On the other hand, when the output signal S14 of the selection circuit 14 is 1, the output signal S6 of the moving image signal processing circuit 6 is effective only for the moving image display processing circuit 8. The moving image signal processing circuit 6 resizes the output signal S2 of the image sensor 2 so as to have the same angle of view as that of the moving image processing, and outputs the output signal S6 as an interlaced scanning video signal. Alternatively, the moving image signal processing circuit 6 may output an image indicating that still image recording has been performed as the output signal S6.

  Since the moving image recording processing circuit 7 is recording a moving image when the output signal S131 of the CPU 13 is 1, the moving image recording processing circuit 7 records the output signal S6 of the moving image signal processing circuit 6 on the moving image recording medium. The moving image recording processing circuit 7 does not record any moving image when the output signal S131 of the CPU 13 is 0, and therefore does not perform any processing.

  The scanning line interpolation circuit 9 performs interlaced scanning line interpolation processing, and outputs a progressive scanning video signal as an output signal S9. In the scanning line interpolation processing, for example, a field memory for delaying the input signal by one field is used, and motion determination and oblique determination are performed from information on the current field and the previous field to create an interpolation line signal. By outputting the interpolated line signal and the input signal, a progressive scanning video signal is output. This scanning line interpolation process is an example, and an interpolation signal may be generated using a plurality of fields.

  The still image signal processing circuit 10 performs processes such as still image aperture correction, gamma correction, and white balance on the output signal S2 of the image sensor 2, and outputs the result as an output signal S10.

  The selector 11 selects either the output signal S9 of the scanning line interpolation circuit 9 or the output signal S10 of the still image signal processing circuit 10 and outputs it as the output signal S11. When the output signal S14 of the selection circuit 14 is 0, the selector 11 outputs the output signal S9 of the scanning line interpolation circuit 9 as the output signal S11. On the other hand, when the output signal S14 of the selection circuit 14 is 1, the selector 11 outputs the output signal S10 of the still image signal processing circuit 10 as the output signal S11.

  The still image recording processing circuit 12 uses the output signal S11 of the selector 11 and the output signal S132 of the CPU 13 as input signals. When the output signal S132 of the CPU 13 is 1, it means that the still image recording operation has been performed, so the still image recording processing circuit 12 records the output signal S11 of the selector 11 on the still image recording medium. When the output signal S132 of the CPU 13 is 0, it means that the still image recording operation is not performed, so the still image recording processing circuit 12 does not perform any processing.

  The CPU 13 outputs 1 as the output signal S131 when the moving image recording is in progress, and outputs 0 as the output signal S131 when the moving image recording standby is in progress. The CPU 13 outputs 1 as the output signal S132 when the still image recording is performed, and outputs 0 as the output signal S132 when the still image recording is not performed.

  The evaluation value generation unit 15 generates an evaluation value S15 that represents the state of the captured moving image. FIG. 7 is a detailed block diagram of the configuration of the evaluation value generation unit 15. In FIG. 7, 701 is an input terminal to which the output signal S6 of the moving image signal processing circuit 6 is input, 702 is a frame memory, 703 is a motion vector detection circuit, 704 is a motion vector magnitude histogram generation circuit, and 705 is a motion vector direction histogram. It is a generation circuit. 706 is a region-specific motion vector magnitude histogram generation circuit, 707 is a first histogram determination circuit, 708 is a second histogram determination circuit, 709 is a third histogram determination circuit, 710 is a specific subject detection circuit, and 711 is a main subject. It is a judgment part. Reference numeral 712 denotes a luminance level evaluation value detection circuit, reference numeral 713 denotes a subject luminance determination unit, reference numeral 714 denotes a color evaluation value detection circuit, and reference numeral 715 denotes a subject color determination unit.

  Hereinafter, the operation of the evaluation value generation unit 15 will be described. The video signal S 701 processed by the moving image signal input from the input terminal 701 includes a frame memory 702, a motion vector detection circuit 703, a specific subject detection circuit 710, a luminance level evaluation value detection circuit 712, and a color evaluation value detection circuit 714. Is input.

  The motion vector detection circuit 703 calculates a motion vector from the video signal S702 delayed by one frame by the frame memory 702 and the video signal S701. As shown in FIG. 8, the motion vector is calculated for each of 256 small blocks, with the shooting angle of view divided into 16 parts in the vertical and horizontal directions, and is separated into sizes and directions. As a result, 256 motion vector magnitude data groups S703-1 and motion vector direction data group S703-2 are generated. The motion vector magnitude data group S703-1 is input to a motion vector magnitude histogram generation circuit 704 and an area-specific motion vector magnitude histogram generation circuit 706. The motion vector direction data group S703-2 is input to the motion vector direction histogram generation circuit 705.

  The motion vector magnitude histogram generation circuit 704 generates the motion vector magnitude histogram data S704 from the 256 motion vector magnitude data groups S703-1, as shown in FIG. To enter.

  The first histogram determination circuit 707 also receives the first motion magnitude detection threshold value S716 and the first motion magnitude frequency threshold value S717. As shown in FIG. 9, the first histogram determination circuit 707 determines whether or not there are a predetermined number or more of blocks in which a predetermined magnitude of motion is detected, and outputs a first motion determination output S707. To do. In a situation where the motion determination output S707 is asserted, it is determined that the subject of the captured moving image is moving and that the moving subject is moving in a predetermined area and a predetermined size.

  The motion vector direction histogram generation circuit 705 generates motion vector direction histogram data S705 from the 256 motion vector direction data groups S703-2 as shown in FIG. 10, and inputs the motion vector direction histogram data S705 to the second histogram determination circuit 708. .

  The second histogram determination circuit 708 also receives a motion direction frequency threshold value S718. As shown in FIG. 10, the second histogram determination circuit 708 determines whether or not there are a predetermined number or more of blocks in which motion in a predetermined direction is detected, and outputs a second motion determination output S708. . In a situation where the determination output S708 is asserted, it can be determined that the subject of the captured moving image has movements aligned in a specific direction.

  The area-specific motion vector magnitude histogram generation circuit 706 receives 256 motion vector magnitude data groups S703-1. As shown in FIG. 11, the generation circuit divides 256 motion vectors into a screen center portion and a screen periphery portion, and generates motion vector magnitude histogram data S706 in each region. 709 is entered.

  The third motion determination circuit 709 also receives the second motion magnitude detection threshold value S719 and the second motion magnitude frequency threshold value S720. As shown in FIG. 12, the third histogram determination circuit 709 determines whether or not there are a predetermined number or more of blocks in which a predetermined amount of motion has been detected for each of the central portion and the peripheral portion of the screen. When the presence of motion is determined only in the peripheral portion, the third motion determination output S709 is output. FIG. 12A shows a peripheral region histogram, and FIG. 12B shows a central region histogram. In a situation where the motion determination output S709 is asserted, it can be determined that the subject of the captured moving image is relatively stationary and has a background motion, and that the subject is a panning shot.

  The specific subject detection circuit 710 detects, from the input video signal S701, in which position a subject having a specific feature such as a human face exists in the captured moving image, and a plurality of subjects The position information S710 is output. The main subject determination unit 711 determines one specific subject from the plurality of subject position information S710 and outputs main subject position information S711. With reference to the main subject position information S711, it is possible to determine whether or not a specific subject exists in the captured moving image.

  The luminance level evaluation value detection circuit 712 extracts, for example, a luminance signal from the video signal S701, divides the screen into, for example, a plurality of blocks with respect to the luminance signal of the captured moving image, and integrates the luminance signal for each of the plurality of blocks. The brightness level evaluation value S712 is generated by generating a value. The brightness level evaluation value S712 and the subject brightness determination level S721 are input to the subject brightness determination unit 713. For example, the subject brightness determination unit 713 compares the brightness evaluation value at the center portion of the screen with the subject brightness determination level S721, and outputs the subject brightness level determination result S713. With reference to the subject brightness level determination result S713, it is possible to determine what value the subject brightness is compared to the subject brightness determination level S721.

  The color evaluation value detection circuit 714 extracts, for example, a color difference signal from the video signal S701, divides the screen into, for example, a plurality of blocks with respect to the color difference signal of the captured moving image, and a color difference having a specific value for each of the plurality of blocks. Only the signal is integrated to generate a specific color evaluation value S714. The specific color evaluation value S714 and the subject color determination level S722 are input to the subject color determination unit 715 at 715. The subject color determination unit 715 determines, for example, whether a specific color is concentrated in the center portion of the screen, and outputs a subject color level determination result S715. With reference to the subject color level determination result S715, it can be determined whether the subject color is included in a specific color difference signal range.

  As described above, the evaluation value S15 from the evaluation value generation unit 15 includes the first to third motion determination outputs S707, S708, and S709, the main subject position information S711, the luminance level determination result S713 of the subject, It consists of the subject color level determination result S715. As a result, the evaluation value S15 includes subject movement information, information on whether or not a specific part exists, information for identifying a specific subject among a plurality of subjects, information on subject luminance, and information on subject color. Represents at least one of them.

  The image evaluation unit 16 performs moving image drive determination and still image drive determination as follows based on the evaluation value S15.

  First, when the image evaluation unit 16 detects a motion of a predetermined magnitude or more fixed in a predetermined direction in the captured moving image from the first motion determination output S707 and the second motion determination output S708. A determination signal S16 for moving image driving is generated. Accordingly, it is possible to cope with a large amount of movement of the subject that is easily detected by appearance so as not to become unnatural.

  Also, the image evaluation unit 16 determines from the third motion determination output S709 that the photographer is intentionally taking a panning shot (if the motion is larger in the periphery than the subject in the center of the moving image). If it is determined, a determination signal S16 that the image sensor 2 should be driven for a still image is generated. If the image evaluation unit 16 determines from the main subject position information S711 that a specific part such as the face of the subject exists in the captured moving image, the image evaluation unit 16 captures the subject intended by the photographer. The determination signal S16 indicating that the drive is to be performed for a still image based on the above assumption is generated. As a result, even if unnaturalness occurs in the large movement of the subject that is easily detected visually, it is handled on the premise that it is as intended by the photographer.

  The image evaluation unit 16 generates a still image drive determination signal S16 when it is determined from the subject brightness level determination result S713 that the subject brightness is lower than the threshold value. Further, when the image evaluation unit 16 determines that the subject color is close to yellow (within a specific color difference range centered on yellow) based on the subject color level determination result S715, the image evaluation unit 16 generates a moving image drive determination signal S16. Generate. As a result, the image evaluation unit 16 responds to the unnaturalness of the movement of the subject according to the ease of detection.

  The image evaluation unit 16 may not be able to uniquely determine whether the determination signal S16 is moving image driving or still image driving for S707, S708, S709, S711, S713, and S715 constituting the evaluation value S15. In this case, a predetermined priority order, majority decision, a known multivariate analysis result, a known neural network determination result, etc. may be used.

  The selection circuit 14 uses the output signal S132 of the CPU 13 and the determination signal S16 for driving the image sensor as input signals. When the output signal S132 of the CPU 13 is 1 (still image recording) and the determination signal S16 is the moving image drive determination, the output signal S14 of the selection circuit 14 is 0, and the image sensor 2 is controlled by interlaced scanning field moving image drive. The The moving image signal processing circuit 6 performs image processing for interlaced scanning field moving images, and the moving image recording processing circuit 7 and the moving image display processing circuit 8 are supplied with field moving images. The selector 11 transmits the output signal S9 of the scanning line interpolation circuit 9 to the still image recording processing circuit 12.

  When the output signal S132 of the CPU 13 is 1 and the determination signal S16 for driving the image sensor is a still image drive determination, the output signal S14 of the selection circuit 14 is 1, and the image sensor 2 is controlled by still image driving of progressive scanning. Is done. The output signal S6 of the moving image signal processing circuit 6 is effective only for the moving image display processing circuit 8, and the output signal S2 of the image sensor 2 is resized so as to have the same angle of view as that of the moving image processing. An output signal S6 is output as a video signal for race scanning. Alternatively, an image indicating that still image recording has been performed may be output as the output signal S6. The still image signal processing circuit 10 performs image processing for still images by progressive scanning, and the selector 11 transmits the output signal S10 of the still image signal processing circuit 10 to the still image recording processing circuit 12.

  According to the present embodiment, both the moving image and still image shooting operations are simplified, and still image shooting can be performed during moving image shooting so as not to miss a photo opportunity. In this case, it is possible to suppress degradation of the resolution in the recorded still image. Further, it is possible to suppress an unnatural motion generated in a moving image to be displayed and recorded within a range that is not detected by the user of the video camera or within an allowable range even if it is detected.

It is a block diagram of the video camera of a present Example. It is a circuit diagram which shows the detail of a structure of the image pick-up element shown in FIG. 3 is a timing chart of the image sensor shown in FIG. 2. 3 is a timing chart of the image sensor shown in FIG. 2. 3 is a timing chart of the image sensor shown in FIG. 2. 3 is a timing chart of the image sensor shown in FIG. 2. It is a block diagram which shows the detail of a structure of the evaluation value production | generation part shown in FIG. It is an example of image division of motion vector detection of the present embodiment. It is an example of the motion vector magnitude | size histogram of a present Example. It is an example of the motion vector direction histogram of a present Example. It is an example of the motion vector magnitude | size histogram according to an area | region of a present Example. It is an example of a peripheral area | region histogram and a center area | region histogram.

Explanation of symbols

2 Image sensor 3 Image sensor drive circuit I (first drive circuit)
4 Image sensor drive circuit II (second drive circuit)
5 Selector (first selector)
6 moving image signal processing circuit 7 moving image recording processing circuit 8 moving image display processing circuit 9 scanning line interpolation circuit 10 still image signal processing circuit 11 selector (second selector)
12 Still Image Recording Processing Circuit 13 CPU (Control Unit)
14 selection circuit 15 evaluation value generation unit 16 image generation unit

Claims (8)

An image sensor for imaging a subject;
A first drive circuit that generates a first drive signal for driving the image sensor so as to convert an image captured by the image sensor into an electrical signal by interlace scanning;
A second drive circuit that generates a second drive signal for driving the image sensor so as to progressively scan an image captured by the image sensor and convert the image into an electrical signal;
A moving image signal processing circuit that performs moving image signal processing on the output of the image sensor and outputs a first video signal based on interlaced scanning;
Based on the first video signal of the moving image signal processing circuit, an evaluation value generation unit that generates an evaluation value representing a state of a moving image;
Based on the evaluation value of the evaluation value generation unit, when the movement of the subject is detected in the moving image, it is determined that the image sensor should be driven for moving images, and the movement of the subject is detected in the moving image. An image evaluation unit that determines that the image sensor should be driven for a still image if not,
When the image evaluation unit determines that the image sensor is to be driven for moving images, a first state signal indicating that still image recording has been performed during movie shooting standby, movie shooting, or movie shooting is performed. And a selection circuit that generates a second state signal indicating that the still image recording has been performed when the still image recording is performed,
A first selector that selects the first drive circuit based on a first state signal of the selection circuit and selects the second drive circuit based on a second state signal of the selection circuit;
An imaging device comprising:   The image evaluation unit determines that the image sensor should be driven for a still image when it is determined that the movement is larger in the peripheral part than the subject in the central part of the moving image. The imaging device according to claim 1.   The imaging apparatus according to claim 1, wherein the image evaluation unit determines that the imaging element should be driven for a still image when it is determined that a specific part exists in the moving image.   The imaging apparatus according to claim 1, wherein the image evaluation unit determines that the imaging element should be driven for a still image when the luminance of the subject is determined to be lower than a threshold value.   The image evaluation unit, when determining that the color of the subject is within a specific color difference range centering on yellow, determines that the image sensor should be driven for moving images. The imaging apparatus according to 1.   The evaluation value includes information on the movement of the subject, information on whether or not a specific part exists, information for identifying a specific subject among a plurality of subjects, information on the luminance of the subject, and information on the color of the subject. The imaging apparatus according to claim 1, wherein at least one of them is represented. A still image signal processing circuit that performs signal processing for a still image on the output of the image sensor and outputs a second video signal based on progressive scanning;
A scanning line interpolation circuit for interpolating a scanning line to the first video signal of the moving image signal processing circuit and converting it to a third video signal based on progressive scanning;
The third video signal of the scanning line interpolation circuit is selected in response to the first state signal of the selection circuit, and the third image signal of the still image signal processing circuit is selected in response to the second state signal of the selection circuit. A second selector for selecting two video signals;
A still image recording processing circuit for recording the output of the second selector when still image recording is performed;
The imaging apparatus according to claim 1, further comprising:   The imaging apparatus performs a process of displaying the first video signal of the video signal processing circuit regardless of whether the first selector selects the first driving circuit or the second driving circuit. The imaging apparatus according to claim 1, further comprising: