JP3810015B2 - Imaging device - Google Patents

Description

  The present invention relates to an imaging apparatus such as a video camera, and more particularly to exposure control when generating a video signal of a still image.

Video cameras have been attracting attention as video input means for computers and the like because various functions have been developed along with the digitization of signal processing, but digital video signals can be easily output. The video handled by a computer or the like is generally a still image, and in order to obtain a video signal of a still image, currently, among the moving images output from a camera-integrated VTR using a consumer-use camera-integrated VTR The video signal for one arbitrary field or one frame is recorded in a memory or the like. The video signal recorded in the memory or the like is input to the computer as a still image. A technique for outputting a still image with proper exposure in a video camera has been proposed (see, for example, Patent Document 1).
JP-A-2-288679

  However, the image input method is not a preferable method because of the following problems.

  (1) Making an automatic control system compatible with still images. In general video cameras, exposure control is performed using video signals. That is, it does not have a separate detector for detecting the illuminance of the subject, but is detected from the video signal and fed back to each control unit. However, even if it detects from the video signal of a still picture, it cannot feed back to the detected still picture.

  (2) A still image of a frame can be generated using a general imaging device. A general imaging device is a destructive readout in which a pixel signal can be read only once and is adjacent in the vertical direction. This is a pixel mixing method in which signals from two pixels are mixed and read out. If signal processing is performed in the above readout method, a still image having a resolution corresponding to the number of pixels cannot be generated.

  An object of the present invention is to solve these problems and to capture a full frame still image with a normal video camera (iris and signal processing).

  In order to solve the above problem (1), the present invention provides a light amount limiting means for blocking a part of incident light, photoelectrically converting incident light for each pixel, and charge converted by the pixel at an arbitrary time. A solid-state imaging device having a shutter function to be swept away, a signal processing means for outputting a signal photoelectrically converted by the solid-state imaging device as a video signal, an exposure by controlling the shutter function of the light quantity limiting means and the solid-state imaging element In addition to adjusting the amount, exposure control means for performing exposure control of the light amount limiting means and the shutter function with an exposure amount specified at the time of previous moving image shooting at the time of still image shooting.

  In order to solve the above problem (2), in the present invention, the signal processing means further includes a case where the solid-state imaging device outputs pixel signals independently and a case where pixel signals are mixed and output. A video signal is generated by different signal processing.

  According to the means for solving the problem (1), the detection result at the time of moving image capturing is stored, and an operation is performed to generate a still image based on the detection result.

  Further, according to the means for solving the problem (2), at the time of taking a still image, the pixel signal is read without mixing by changing the driving method of the image sensor, and the video signal of the still image is read to the signal processing circuit. When is input, the signal processing content is switched to still image.

  According to the present invention, it is possible to provide an imaging apparatus that can perform accurate exposure control when capturing a still image and can capture a high-quality still image.

  Hereinafter, the present invention will be described with reference to the drawings.

  FIG. 1 is a configuration diagram of an imaging apparatus according to the first embodiment of the present invention. In the figure, 101 is a lens, 102 is a mechanical shutter, 103 is an image sensor, 104 is an amplifier, 105 is an A / D converter, 106 is a video signal processing circuit, 107 is a camera control circuit, 108 is a mechanical shutter control circuit, 109 is An image sensor driving circuit 110 is a shutter button. A specific example of the image sensor 103 is shown in FIG. In FIG. 2, 201 is a photodiode, 202 is a vertical CCD, 203 is a horizontal CCD, gr, mg, cy and ye are color filters arranged on the respective surfaces of the photodiode 201, and gr is a green color. , Mg indicates magenta, cy indicates cyan, and ye indicates a yellow color filter. A photodiode provided with such a color filter is generally called a pixel. The light input through the lens 101 is input to the image sensor 103 through the mechanical shutter 102 whose aperture value F is controlled by the mechanical shutter control circuit 108, is photoelectrically converted by the photodiode 201 disposed on the surface of the image sensor 103, and is vertically Pixels are mixed in the CCD 202 and output via the horizontal CCD 203. The output signal of the image sensor 103 is amplified by the amplifier 104, converted into a digital signal by the A / D converter 105, and input to the video signal processing circuit 106. The video signal processing circuit 106 converts the input signal into a video signal such as NTSC and outputs it, and outputs luminance information of the subject to the camera control circuit 107. The camera control circuit 107 controls the mechanical shutter control circuit 108 so that the output of the video signal processing circuit 106 has a desired luminance level based on the luminance information of the subject, changes the aperture value of the mechanical shutter 102, and is necessary. Accordingly, the image sensor driving circuit 109 is controlled to control the electronic shutter speed of the image sensor 103.

  Next, the electronic shutter will be briefly described. FIG. 3 is a diagram schematically showing the potential of the image sensor 103. In this figure, 301 is a charge stored in the image sensor 103, 302 is a readout gate, 303 is a substrate voltage, 304 is a well, and 305 is a channel stopper. The charge photoelectrically converted by the photodiode 201 is stored between the read gate 302 and the well 304 as shown in the figure. When a charge sweeping pulse is supplied from the image sensor drive circuit 109 to the image sensor 103, the potential of the substrate voltage 303 decreases. Then, as shown in FIG. 4, the potential of the well 304 is lowered while being pulled by the substrate voltage 303. Then, the charge 301 is swept away to the portion of the substrate voltage 303. The channel stopper 305 is for preventing leakage of charges from the vertical CCD 202 corresponding to the adjacent pixel.

  In this configuration, when the shutter button 110 is pressed, a shutter close control signal is input from the camera control circuit 107 to the mechanical shutter control circuit 108. The mechanical shutter control circuit 108 causes the mechanical shutter 102 to enter the closed state after a predetermined time. Become. The light input to the image sensor 103 until the mechanical shutter 102 is closed is photoelectrically converted by the photodiode 201 disposed in the image sensor 103 in the same manner as the above operation, and the mechanical shutter 102 is in the closed state. The data is transferred to the horizontal CCD 203 via the vertical CCD 202, and is subjected to voltage conversion in synchronization with the horizontal scanning pulse supplied from the image sensor driving circuit 109 and output. At this time, when the image sensor 103 reads the signal once from the photodiode 201, no signal remains in the photodiode 201, so-called destructive readout. The frame information is lost.

  Hereinafter, pixel mixed readout will be described. The image sensor 103 is a so-called pixel mixing method that reads and mixes two adjacent pixel signals in the vertical direction as described in JP-A-63-114487 until the shutter button 110 is pressed. Is read.

  FIG. 5 shows a vertical transfer pulse at the time of pixel mixed readout and a signal charge transfer timing chart in the vertical CCD 202. In the figure, when the ternary pulse of the vertical transfer pulse 1 becomes a high level, the photo diode 201 of the row of gr and mg starts from the photodiode 201 of the row of the vertical transfer pulse 3, and when the ternary pulse of the vertical transfer pulse 3 becomes a high level, the rows of cy and yes. Signal charges are transferred from the photodiode 201 to the vertical CCD 202 respectively. The signal charges transferred to the vertical CCD 202 are mixed in the vertical CCD 202 as shown in FIG. 5, transferred to the horizontal CCD 203, and output from the image sensor 103.

  However, if the above-described pixel mixture readout is performed at the time of still image capturing, the resolution corresponding to the number of pixels in the vertical direction of the image sensor 103 cannot be obtained. Therefore, the following independent readout is performed at the time of still image capturing. FIG. 6 shows a vertical transfer pulse at the time of independent reading and a timing chart of signal charge transfer in the vertical CCD 202. In FIG. 6, the period when the ternary pulses of the vertical transfer pulse 1 and the vertical transfer pulse 3 become high level is every other field as shown in FIG. Therefore, in the field where the ternary pulse of the vertical transfer pulse 1 is at a high level, the signal charge is transferred to the vertical CCD 202 only from the photo diode 201 of the gr and mg rows, and in the next one field, the vertical transfer is performed. When the ternary pulse of pulse 3 becomes high level, signal charges are transferred to the vertical CCD 202 only from the photodiodes 201 in the cy and mg rows. Since the signal charges transferred to the vertical CCD 202 are all transferred to the horizontal CCD 203 in one field period, the signal charges of the adjacent photodiodes 201 are mixed as in the above-described pixel mixture reading method. In other words, one signal can be obtained for one photodiode. Hereinafter, the signal charge transferred to the horizontal CCD 203 is output from the image sensor 103 in synchronization with the horizontal scanning pulse supplied from the image sensor drive circuit 109. The output signal of the image sensor 103 is amplified by the amplifier 104, converted into a digital signal by the A / D converter 105, and input to the video signal processing circuit 106. The video signal processing circuit 106 converts the input signal into a video signal and outputs it. However, in performing the independent reading, in order to make the exposure amount of the photodiodes in the gr and mg rows equal to the exposure amount of the photodiodes in the cy and yes rows, exposure for still image capturing is performed. The mechanical shutter 102 must be fully closed for at least a period from the start to the end of reading of the signal. Further, the amount of exposure for the image sensor 103 is determined immediately after the signal charge photoelectrically converted by the photodiode 201 of the image sensor 103 is transferred to the vertical CCD 202 immediately before the mechanical shutter 102 is fully closed. This is the amount of light incident on 103.

  FIG. 7 is a graph showing the exposure amount to the image sensor 103 with respect to the aperture value of the mechanical shutter 102. In the exposure control of the video camera of this embodiment, the same operation as that of a normal video camera is performed until the shutter button 110 is pressed. That is, the electric charge accumulated in the image sensor 103 for one field period is read out every field, the exposure amount is calculated from the luminance signal generated by the signal processing circuit, and the mechanical shutter control circuit 108 controls the diaphragm of the mechanical shutter 102 so that the predetermined exposure amount is obtained. To do. When the electronic shutter is not used, the exposure of the image sensor 103 is started from time t1 to t4 when charge transfer from the photodiode 201 to the vertical CCD 202 is performed. Therefore, it is assumed that the shutter button 110 is pressed between time t3 and t4. Then, exposure for generating a still image is started from time t4. At this time, it is assumed that the area (exposure amount) indicated by A is an appropriate exposure amount for the subject currently being imaged. In order to obtain an appropriate exposure amount at the time of still image capturing, the mechanical shutter 102 is operated so that the area indicated by B and the area indicated by A, which are the exposure amounts during the period of time t4 to t5, are equalized. An appropriate exposure amount can be obtained even during imaging.

  Next, a second embodiment of the present invention will be described with reference to the drawings.

  In the imaging apparatus shown in FIG. 1 in the first embodiment described above, the noise component in the moving image imaging signal has a different phase for each field and is smoothed by the human eye. The noise component did not bother me much. However, in the case of a still image, since the above smoothing is not performed, it is necessary to improve the S / N ratio at the time of capturing a still image as compared with an imaging device that captures a conventional moving image.

  Means for improving the S / N will be described below with reference to FIG. In the figure, the charge photoelectrically converted by the photodiode 201 is stored between the readout gate 302 and the well 304 as shown in the figure. At the time of moving image reading, the vertical transfer pulse 1 and 3 ternary pulse once in a field goes high, thereby lowering the potential of the read gate 302 and transferring the charge 301 to the vertical CCD 202. . At this time, if the potential of the readout gate shown in the figure is lowered by the ternary pulse of the vertical transfer pulse 1 becoming high level, the potential of the readout gate of the pixels adjacent in the vertical direction is It is assumed that the ternary pulse of the vertical transfer pulse 3 is lowered by the high level. The charges 301 read out by the above method are mixed in the vertical CCD 202 with the charges photoelectrically converted by the photodiodes adjacent above or below. At the time of still image capturing, only the ternary pulse of the vertical transfer pulse 1 is set to the high level in the first field where reading starts, and only the ternary pulse of the vertical transfer pulse 3 is set to the high level in the second field. By setting the level, the charge 301 is read without performing the pixel mixing. At this time, as long as the charge 301 does not overflow between the readout gate 302 and the well 304, the vertical CCD 202 and the horizontal CCD 203 are charged even if a larger amount of charge 301 is accumulated in one pixel than in the moving image capturing. Can be transferred. By accumulating a large amount of charges in the image sensor 103 based on the above method, the S / N is improved.

  Next, a third embodiment of the present invention will be described with reference to the drawings.

  The configuration of the imaging apparatus according to the third embodiment of the present invention is the same as that of the first embodiment, and will be described with reference to FIG. Further, description of portions common to the first embodiment is omitted. As shown in the above-described embodiment, when capturing a still image, it is more advantageous to have more light incident on the image sensor 103 and accumulate more charge. Hereinafter, exposure control during still image capturing will be described with the amount of charge accumulated in the image sensor 103 being 1.5 times that during moving image capturing.

  FIG. 8 is a diagram showing the exposure amount to the image sensor 103 with respect to the aperture value of the mechanical shutter 102 and the transfer timing of charges from the photodiode 201 to the vertical CCD 202 in this embodiment. In the imaging apparatus, before entering a still image imaging operation, exposure control similar to that of a general video camera is performed as described in the first embodiment. Here, for the sake of simplicity, only the time for capturing a moving image is shown for three fields, but the length of time for capturing a moving image is an arbitrary length until the exposure control is sufficiently stabilized, and then the shutter button 110. Is the time until is pressed. If the shutter button 110 is pressed at the time indicated by ts in FIG. 8 after the moving image exposure control is stabilized, a shutter close control signal is input from the camera control circuit 107 to the mechanical shutter control circuit 108, and mechanical shutter control is performed. By the circuit 108, the mechanical shutter 102 starts the closing operation from the beginning of the next field, that is, from the time t4. That is, exposure for still image capturing starts from time t4. At this time, it is assumed that the mechanical shutter 102 changes its aperture value linearly at a constant speed without inertia, and closes in 3 fields from the current aperture amount. Further, as shown in FIG. 8, the ternary pulses of the vertical transfer pulses 1 and 3 are stopped until the mechanical shutter 102 is closed after time t4, and the reading of charges from the photodiode 201 is stopped. According to the above conditions, the exposure amount at the time of still image capturing, that is, the area indicated by B, is 1.5 times the exposure amount at the time of moving image capturing, that is, the area indicated by A, as in the first embodiment. , An exposure amount that is 1.5 times the exposure amount during the period from time t3 to time t4 shown in FIG. The light incident on the image sensor 103 during the period from t4 to t7 by the above method is increased in the ternary pulse of the vertical transfer pulses 1 and 3 once each at the timings t7 and t8 after the photoelectric conversion and the mechanical shutter 102 is closed. The level is output from the image sensor 103 by the independent reading described above. However, since the independent reading is performed, the video signal processing circuit 106 switches the signal processing to a still image, converts the input signal into a video signal, and outputs the video signal. In addition, since the signal charge stored in the image sensor 103 at this time is 1.5 times that at the time of moving image capturing, the total amount of signal amplification in the subsequent signal processing should be 1 / 1.5 times that at the time of moving image capturing. good.

  Further, since the video signal picked up during the period from t4 to t7 can be read only once, it is recorded in a recording means such as a memory (not shown) when read, and a still image is stored in a computer device or the like as necessary. Output as.

  Next, a fourth embodiment of the present invention will be described with reference to the drawings.

  The configuration of the imaging apparatus according to the fourth embodiment of the present invention is the same as that of the first and third embodiments described above, and will be described with reference to FIG. Further, description of portions common to the first and third embodiments is omitted. Also in the present embodiment, the exposure control during still image capturing will be described with the amount of charge accumulated in the image sensor 103 being 1.5 times that during moving image capturing.

  FIG. 9 is a diagram showing the exposure amount to the image sensor 103 with respect to the aperture value of the mechanical shutter 102 and the transfer timing of charges from the photodiode 201 to the vertical CCD 202 in this embodiment. This embodiment differs from the third embodiment described above in that the illuminance of the subject is higher and the exposure amount to the image sensor 103 is half that of the third embodiment described above. In the imaging apparatus, before entering a still image imaging operation, exposure control similar to that of a general video camera is performed as described in the first embodiment. If the shutter button 110 is pressed at the time indicated by ts in FIG. 9 after the moving image exposure control is stabilized, exposure for still image capturing starts at time t4. At this time, the mechanical shutter 102 linearly changes the aperture value at a constant speed without inertia as in the third embodiment. That is, the time required until the mechanical shutter 102 is closed is also halved to 1.5 fields. At this time, as in the first embodiment described above, if the mechanical shutter 102 is closed from the next field after the shutter button 110 is pressed, that is, the time t4, the exposure amount for still image capturing is set to the time t3. It is not possible to reduce the exposure amount by the exposure control performed at the time of moving image capturing at time t4 to 1.5 times. Therefore, even when the shutter button 110 is pressed, the camera control circuit 107 does not output the shutter close control signal to the mechanical shutter control circuit 108 for a fixed time determined by the following method.

  FIG. 10 is a flowchart showing a series of operations from when the shutter button 110 is pressed until the camera control circuit 107 calculates the predetermined time and outputs a shutter close control signal to the mechanical shutter control circuit 108. . When the shutter button 110 is pressed, a shutter close control signal is input to the camera control circuit 107. The camera control circuit 107 determines the current aperture value of the mechanical shutter 102, and from the current aperture value of the mechanical shutter 102, The time required until the mechanical shutter 102 is closed is calculated. Then, how much the closing operation of the mechanical shutter 102 should be delayed in order to give an exposure amount of 1.5 times the exposure amount by the exposure control performed at the time of moving image capturing at the time of still image capturing is calculated. The camera control circuit 107 outputs a shutter close control signal to the mechanical shutter control circuit 108 after the time obtained by the above calculation after the shutter button 110 is pressed, and closes the mechanical shutter 102. Although not shown, the camera control circuit 107 has means for recognizing the aperture value of the mechanical shutter 102, and calculates the exposure amount to the image sensor 103 from the current exposure amount and the time required until the mechanical shutter 102 is closed. Means for calculating the above-mentioned fixed time required to give an exposure amount 1.5 times that at the time of moving image capturing at the time of still image capturing. In the present embodiment, by setting the fixed time to one field, the exposure amount at the time of still image capturing shown in FIG. The exposure amount at the time, that is, 1.5 times the area indicated by A, and an exposure amount 1.5 times the exposure amount from the time t3 to the time t4 can be given to the image sensor 103. The light incident on the image sensor 103 from t4 until the mechanical shutter 102 is closed by the above method is subjected to photoelectric conversion and the vertical transfer pulses 1 and 3 are each once at timings t7 and t8 after the mechanical shutter 102 is closed. The value pulse is set to a high level and is output from the image sensor 103 by the independent reading described above. However, since the independent reading is performed, the video signal processing circuit 106 switches the signal processing to a still image, converts the input signal into a video signal, and outputs the video signal. In addition, since the signal charge stored in the image sensor 103 at this time is 1.5 times that at the time of moving image capturing, the total amount of signal amplification in the subsequent signal processing should be 1 / 1.5 times that at the time of moving image capturing. good.

  Since the video signal picked up from the time t4 to the time when the mechanical shutter 102 is closed can be read only once, it is recorded in a recording means such as a memory (not shown) when read, and a computer device if necessary. Etc. as a still image.

  At the time of still image capturing, an exposure amount that is 1.5 times the exposure amount at the time of moving image capturing can be obtained. Needless to say, when the subject is brighter and the amount of exposure is smaller, the predetermined time becomes longer accordingly. As in the third embodiment described above, as shown in FIG. 9, the ternary pulses of the vertical transfer pulses 1 and 3 are stopped until the mechanical shutter 102 is closed after time t4, and the charge is read out from the photodiode 201. Stop.

  Next, a fifth embodiment of the present invention will be described with reference to the drawings.

  The present embodiment has parts in common with the third embodiment described above, and different parts will be described. Also in the present embodiment, the exposure control during still image capturing will be described with the amount of charge accumulated in the image sensor 103 being 1.5 times that during moving image capturing.

  FIG. 11 shows the exposure amount to the image sensor 103 with respect to the aperture value of the mechanical shutter 102 in this embodiment, the charge transfer timing from the photodiode 201 to the vertical CCD 202, and the charge sweep pulse supplied from the image sensor drive circuit 109. It is a figure which shows the timing of. This embodiment is different from the third embodiment described above in that the illuminance of the subject is lower and the exposure amount to the image sensor 103 is twice that in the third embodiment described above. In the imaging apparatus, before entering a still image imaging operation, exposure control similar to that of a general video camera is performed as described in the first embodiment. If the shutter button 110 is pressed at the time indicated by ts in FIG. 11 after the moving image exposure control is stabilized, exposure for still image capturing is started from the time t4. At this time, the mechanical shutter 102 linearly changes the aperture value at a constant speed without inertia as in the third embodiment. That is, the time required until the mechanical shutter 102 is closed is doubled to 6 fields. At this time, if the mechanical shutter 102 is closed from the next field when the shutter button 110 is pressed, that is, the time t4, the exposure amount for still image capturing is the exposure performed at the time of moving image capturing from the time t3 to the time t4. It becomes 3 times the exposure amount by control. Therefore, while the mechanical shutter 102 is closing from the time t4 when the shutter button 110 is pressed, the camera control circuit 107 uses the electronic shutter function of the imaging element 103 for a certain time determined by the following method. The charge accumulated in the photodiode 201 is swept away.

  FIG. 12 is a flowchart showing a series of operations from when the shutter button 110 is pressed until the camera control circuit 107 calculates the predetermined time and outputs a shutter close control signal to the mechanical shutter control circuit 108. . When the shutter button 110 is pressed, a shutter close control signal is input to the camera control circuit 107. The camera control circuit 107 determines the current aperture value of the mechanical shutter 102, and from the current aperture value of the mechanical shutter 102, The time required until the mechanical shutter 102 is closed is calculated. Then, it is calculated how much charge should be swept out from the time t4 by the electronic shutter function in order to give an exposure amount 1.5 times the exposure amount by the exposure control performed at the time of moving image capturing at the time of still image capturing. . The camera control circuit 107 outputs a shutter close control signal to the mechanical shutter control circuit 108 to close the mechanical shutter 102 from time t4 after the shutter button 110 is pressed, and at the same time, the time obtained by the above calculation, The image sensor driving circuit 109 is controlled to supply the image sensor 103 with a charge sweeping pulse. Although not shown, the camera control circuit 107 has means for recognizing the aperture value of the mechanical shutter 102, and calculates the exposure amount to the image sensor 103 from the current exposure amount and the time required until the mechanical shutter 102 is closed. Means for calculating the above-mentioned fixed time required to give an exposure amount 1.5 times that at the time of moving image capturing at the time of still image capturing. In the present embodiment, by setting the fixed time to approximately 2 fields, it is possible to obtain an exposure amount that is 1.5 times the exposure amount during moving image capturing during still image capturing. Needless to say, if the subject is darker and the amount of exposure is larger, the predetermined time becomes longer accordingly.

  Since the video signal picked up from the time t4 to the time when the mechanical shutter 102 is closed can be read only once, it is recorded in a recording means such as a memory (not shown) when read, and a computer device if necessary. Etc. as a still image. As in the third embodiment described above, as shown in FIG. 11, the ternary pulses of the vertical transfer pulses 1 and 3 are stopped until the mechanical shutter 102 is closed after time t4, and the charge is read from the photodiode 201. Stop.

  Next, a sixth embodiment of the present invention will be described with reference to the drawings.

  FIG. 13 is a configuration diagram of an imaging apparatus according to the sixth embodiment of the present invention. The same reference numerals are given to the same parts as those in the first embodiment, and the description will be omitted. In the figure, 1301 is a mechanical shutter, 1302 is an EEPROM (electrically rewritable ROM), and in the third, fourth and fifth embodiments described above, the mechanical shutter 102 is linear at a constant speed without inertia. However, the mechanical shutter 1301 has inertia. That is, the shutter closing operation performed by the mechanical shutter 1301 after the shutter button 110 is pressed and the shutter close control signal is input to the mechanical shutter control circuit 108 follows the locus shown in FIG. The trajectory shown in FIG. 14 differs depending on the type of the mechanical shutter 1301, and even the same type of mechanical shutter is not necessarily the same due to individual variations. Therefore, the locus during the closing operation of the mechanical shutter 1301 used is recorded in the EEPROM 1302 in advance. FIG. 14 shows only three types of aperture values of the mechanical shutter 1301, but the locus of the closing operation of the mechanical shutter 1301 at each arbitrary aperture value is recorded in the EEPROM 1302 as necessary. The data recorded in the EEPROM 1302 may be recorded during automatic adjustment in the production process.

  Note that the locus of the closing operation of the mechanical shutter 1301 at each arbitrary aperture value may be recorded in other recording means.

  Hereinafter, exposure control during still image capturing in the present embodiment will be described. Similar to the first, third, fourth, and fifth embodiments described above, before performing a still image capturing operation, a moving image similar to a general video camera is captured and exposure control performed by the general video camera is performed. To do. 15, 16, and 17 show the exposure amount to the image sensor 103 with respect to the aperture value of each mechanical shutter 1301 and the transfer timing of charges from the photodiode 201 to the vertical CCD 202 when still image capturing is performed in the present embodiment. FIG. 18 is a flowchart showing an exposure control operation when a still image is captured after the shutter button 110 is pressed.

  As shown in FIG. 18, after the exposure control of the moving image is stabilized, when the shutter button 110 is pressed at an arbitrary timing ts, the camera control device 107 displays the locus of the closing operation corresponding to the current aperture value of the mechanical shutter 1301 in the EEPROM 1302. Read from. Then, based on the data from the EEPROM 1302, in order to give an exposure amount 1.5 times the exposure amount by the exposure control performed at the time of moving image capturing at the time of still image capturing, as shown in FIG. The method of delaying the shutter closing operation performed in the fourth embodiment is used, or the electric charge is swept out by the electronic shutter performed in the above-described fifth embodiment as shown in FIG. As described above, it is determined whether the shutter closing operation is performed from time t4 as in the third embodiment. If the determination result is that the shutter closing operation is delayed as in the fourth embodiment, the camera control circuit 107 selects a shown in FIG. 18 and determines how much the shutter closing operation is delayed from time t4. After the calculation time obtained from time t4, that is, at time tss shown in FIG. 15, a shutter close control signal is output to the mechanical shutter control circuit. Further, if the determination result is that the electric shutter sweeps out the electric charge as in the fifth embodiment, b shown in FIG. 18 is selected, and the camera control circuit 107 performs exposure for taking a still image. The time for sweeping out charges by the electronic shutter is calculated from time t4 which is the start time, and a shutter close control signal is output to the mechanical shutter control circuit 108 at time t4. The drive circuit 109 is controlled to sweep out the charge accumulated in the image sensor 103. In addition to the above two cases, that is, when it is not necessary to delay the shutter closing operation or to sweep out the electric charge by the electronic shutter, c shown in FIG. 18 is selected, as in the above-described third embodiment. At time t4, a shutter close control signal is output to the mechanical shutter control circuit 108 to close the mechanical shutter 1301.

  Although not shown, the camera control circuit 107 has means for recognizing the aperture value of the mechanical shutter 1301, and calculates the exposure amount to the image sensor 103 from the current exposure amount and the data supplied from the EEPROM 1302. Means for determining whether any one of the above methods should be used in order to set the time for taking a moving picture to 1.5 times when taking a picture, calculating means for delaying the shutter closing operation, and the charge sweep time by the electronic shutter. Have means for calculating. Since the video signal picked up from the time t4 until the mechanical shutter 1301 is closed can be read out only once, it is recorded in a recording means such as a memory (not shown) when read out, and the computer equipment is used as necessary. Etc. as a still image. As in the third, fourth and fifth embodiments, the ternary pulses of the vertical transfer pulses 1 and 3 are stopped until the mechanical shutter 102 is closed after time t4 as shown in FIGS. The reading of charges from the node 201 is stopped.

It is a block diagram which shows the circuit structure of the image pick-up element which concerns on embodiment of this invention. It is a figure which shows the specific example of the image pick-up element which concerns on embodiment of this invention. It is a figure which shows the potential of the image pick-up element which concerns on embodiment of this invention. It is a figure which shows the potential of the image pick-up element which concerns on embodiment of this invention. 6 is a timing chart illustrating driving of an image sensor according to an embodiment of the present invention. 6 is a timing chart illustrating driving of an image sensor according to an embodiment of the present invention. It is a figure which shows the exposure amount to the image pick-up element which concerns on embodiment of this invention. It is a figure which shows the exposure amount to the image pick-up element which concerns on embodiment of this invention, and the drive of an image pick-up element. It is a figure which shows the exposure amount to the image pick-up element which concerns on embodiment of this invention, and the drive of an image pick-up element. 3 is a flowchart according to an embodiment of the present invention. It is a figure which shows the exposure amount to the image pick-up element which concerns on embodiment of this invention, and the drive of an image pick-up element. 3 is a flowchart according to an embodiment of the present invention. 1 is a block diagram illustrating a circuit configuration of an imaging apparatus according to an embodiment of the present invention. It is a figure which shows the locus | trajectory of the closing operation | movement of the mechanical shutter which concerns on embodiment of this invention. It is a figure which shows the exposure amount to the image pick-up element which concerns on embodiment of this invention, and the drive of an image pick-up element. It is a figure which shows the exposure amount to the image pick-up element which concerns on embodiment of this invention, and the drive of an image pick-up element. It is a figure which shows the exposure amount to the image pick-up element which concerns on embodiment of this invention, and the drive of an image pick-up element. 3 is a flowchart according to an embodiment of the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 101 Lens 102 Mechanical shutter 103 Image pick-up element 104 Amplifier 105 A / D converter 106 Image signal processing circuit 107 Camera control circuit 108 Mechanical shutter control circuit 109 Image pick-up element drive circuit 110 Shutter button 201 Photo diode 202 Vertical CCD
203 Horizontal CCD
301 Charge 302 Reading card 303 Substrate voltage 304 well
305 Channel stopper 1301 Mechanical shutter 1302 EEPROM

Claims (1)

Mechanical shutter,
A solid-state imaging device having an electronic shutter function that photoelectrically converts incident light for each pixel and sweeps away the charge photoelectrically converted by the pixel at an arbitrary time;
Signal processing means for outputting a signal photoelectrically converted by the solid-state imaging device as a video signal of a moving image or a still image ;
Storage means for storing information on the time required to close the mechanical shutter;
Using the information on the time required to close the mechanical shutter stored in the storage means, the electronic shutter function of the solid-state imaging device is controlled to determine the start of exposure time for still image capturing, and the still image is captured by closing the mechanical shutter. Exposure control means for controlling the exposure time of the still image by determining the end of the exposure time of the imaging, and controlling the exposure amount of the still image to be larger than the exposure amount of the moving image ;
Imaging apparatus characterized by comprising a.

Images