JP5408907B2 - Imaging device - Google Patents

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.

  there. 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 drives the image pickup device to perform interlace scanning when recording a still image during moving image recording. And a driving circuit that drives the image sensor to perform progressive scanning when recording images.

  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 sensor drive circuit I3 generates a first vertical / horizontal synchronization signal S3 (first drive signal) for driving the image sensor 2 so that an image captured by the image sensor 2 is interlaced and converted into an electrical signal. It is a drive circuit. The image sensor drive circuit II4 generates a vertical / horizontal synchronization signal S4 (second drive signal) for driving the image sensor 2 so as to progressively scan the image captured by the image sensor 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.

  Reference numeral 30 denotes an analog front end (hereinafter referred to as “AFE”) including a correlated double sampling circuit and an analog / digital (A / D) conversion circuit. The correlated double sampling circuit is a circuit that removes dominant reset noise from noise included in the video output signal S2 of the image sensor 2. The A / D conversion circuit is a circuit that converts an analog image into a digital image. The AFE 30 is a circuit that converts an analog signal into a digital signal that can be processed by the moving image signal processing circuit 6.

  The moving image signal processing circuit 6 uses the output signal S30 of the AFE 30 and the output signal S14 of the selection circuit 14 as input signals, performs signal processing for moving images on the output signal S30 of the AFE 30, and generates a moving image signal based on interlaced scanning (first step). 1 video signal) 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 a process of 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 still image signal processing circuit 10 uses the output signal S30 of the AFE 30 as an input signal, performs signal processing for the still image on the input signal, and outputs a video signal based on progressive scanning as an output signal S10 (second video signal).

  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 S131 from the CPU 13 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 according to the value of the output signal S131 of the CPU 13, 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 an output signal S131 (first identification signal) for identifying whether a moving image is being recorded or is waiting for a moving image recording, and an output signal for identifying whether a still image has been recorded. S132 (second identification signal) is output. If the output signal S131 is 1, it means that the moving image is being recorded, and if the output signal S131 is 0, it means that the moving image is being recorded. If the output signal S132 is 1, it means that still image recording has been performed, and if the output signal S132 is 0, it means that still image recording has not been performed. The CPU 13 determines whether still image recording has been performed during moving image recording, during moving image recording standby, or in accordance with 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 uses the output signals S131 and S132 of the CPU 13 as input signals, and outputs a synchronization signal to be supplied to the image sensor 2 and an output signal S14 that determines the operation of the moving image signal processing circuit 6. The selection circuit 14 generates a signal 0 (first state signal) indicating that still image recording has been performed during movie shooting standby, movie shooting, or movie shooting. 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 which 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 that is 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 pickup device 2 operates as follows based on a synchronization signal supplied from the image pickup device drive circuit I3 or the image pickup device drive circuit II4 via the selector 5. 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 having 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. Thus, in the interlaced scanning, the output signals of 1920 photoelectric conversion elements, which are a part of the plurality of photoelectric conversion elements, become the output signal S2 of the image sensor 2.

  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. Thus, in the interlaced scanning, the average value of the photoelectric conversion output signals of the plurality of photoelectric conversion elements becomes the output signal S2 of the imaging element 2. 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 interlace scanning, the output signal of the image sensor 2 is output in units of one field period.

  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 pickup element driving circuit II4, as shown in FIG. 5, the vertical synchronization with 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, in progressive scanning, all output signals of the plurality of photoelectric conversion elements become output signals of the image sensor 2. Further, in progressive scanning, the output signal of the image sensor 2 is output in units of a plurality of field periods.

  As described above, when the output signal S5 of the selector 5 is the vertical / horizontal synchronization signal S3 output from the image sensor drive circuit I3, the image sensor 2 outputs the interlaced scanning video signal of the field period 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 in 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 with a field period. 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 output signal S30 of the AFE 30 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 S30 of the AFE 30 so as to have the same angle of view as that of the moving image processing, and outputs it as an 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 S30 of the AFE 30, 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 S131 of the CPU 13 is 1 (during moving image recording), 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 S131 of the CPU 13 is 0 (during standby for moving image recording), 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 selection circuit 14 uses the output signals S131 and S132 of the CPU 13 as input signals. When the output signal S131 of the CPU 13 is 0 and the output signal S132 of the CPU 13 is 1, it means that still image recording has been performed during the moving image recording standby. For this reason, the output signal S14 of the selection circuit 14 becomes 1, and the image pickup device 2 is controlled by still image driving of progressive scanning. Also, 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 S30 of the AFE 30 is resized so as to have the same angle of view as the moving image processing, and interlaced scanning is performed. Is output as an output signal S6. 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.

  In other cases, the output signal S14 of the selection circuit 14 is 0, and the image sensor 2 is controlled by interlaced scanning field moving image driving. 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.

  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.

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 30 Analog Front End (AFE)

Claims (10)

An image sensor for imaging a subject;
A drive circuit that drives the image sensor to perform interlace scanning when recording a still image during moving image recording, and drives the image sensor to perform progressive scan when recording a still image during standby for moving image recording; ,
An imaging device comprising: An operation unit capable of video recording and still image recording,
A first identification signal for identifying that a in the moving image recording or the moving image recording standby, the second identification signal for identifying whether the still image recording is performed, the input to the operating unit depending on the imaging apparatus according to claim 1, further comprising a control unit for outputting.   The image pickup apparatus according to claim 1, further comprising a moving image signal processing circuit that outputs a first video signal by performing signal processing for moving images on an output of the image sensor obtained by interlace scanning. A still image signal processing circuit that outputs a second video signal by performing signal processing for a still image on the output of the imaging device obtained by progressive scanning;
A scanning line interpolation circuit for interpolating the first video signal and outputting a third video signal;
Further comprising
When a still image is recorded during moving image recording, the third video signal is recorded as a still image, and when a still image recording is performed during moving image recording standby, the second video signal is stopped. The image pickup apparatus according to claim 3, wherein the image pickup apparatus is recorded as a picture. The imaging apparatus according to claim 3 , further comprising a moving image display processing circuit that performs a process of displaying the first video signal. The imaging element has a plurality of photoelectric conversion elements,
2. The imaging apparatus according to claim 1, wherein in the interlace scanning, an output signal of a part of the plurality of photoelectric conversion elements becomes an output signal of the imaging element. The imaging element has a plurality of photoelectric conversion elements,
2. The imaging apparatus according to claim 1, wherein an average value of output signals of the plurality of photoelectric conversion elements becomes an output signal of the imaging element in the interlace scanning.   8. The image pickup apparatus according to claim 6, wherein an output signal of the image pickup element is output in units of one field period in the interlace scanning. The imaging element has a plurality of photoelectric conversion elements,
2. The imaging apparatus according to claim 1, wherein in the progressive scanning, all output signals of the plurality of photoelectric conversion elements become output signals of the imaging element. 3.   The imaging apparatus according to claim 9, wherein in the progressive scanning, an output signal of the imaging element is output in units of a plurality of field periods.