JP3117056B2 - Imaging device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image pickup apparatus such as a video camera and, more particularly, to an exposure control for generating a video signal of a still image.

[0002]

2. Description of the Related Art While a variety of functions have been developed for video cameras along with the digitization of signal processing,
Because digital video signals can be easily output, they are attracting attention as video input means such as computers. The video handled by a computer or the like is generally a still image. In order to obtain a video signal of a still image, a video camera output from the camera-integrated VTR using a consumer-use camera-integrated VTR is currently used. The video signal for any one 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. JP-A-2-288679 describes a technique for outputting a still image with proper exposure in a video camera.

[0003]

However, the above image input method is not a preferable method due to the following problems.

(1) To enable the automatic control system to handle still images. A general video camera controls exposure using a video signal. That is, there is no separate detector for detecting the illuminance of the subject, but the detector is detected from the video signal and is fed back to each control unit.
However, even if it is detected from a video signal of a still image, it is not possible to feed back to the detected still image.

(2) A still image of a frame can be generated by using a general image pickup element. A general image pickup element is a destructive readout in which a pixel signal can be read out only once, and is vertically read. This is a pixel mixing method in which signals of two pixels adjacent in the direction are mixed and read. If signal processing is performed with 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).

[0007]

SUMMARY OF THE INVENTION In order to solve the above problem (1), the present invention provides a light amount limiting means for blocking a part of incident light, a photoelectric conversion of the incident light for each pixel, and a photoelectric conversion by the pixel. A solid-state imaging device having a shutter function of sweeping out the converted charges at an arbitrary time, a signal processing unit for outputting a signal photoelectrically converted by the solid-state imaging device as a video signal,
And controlling the exposure amount by controlling the light amount limiting means and the shutter function of the solid-state imaging device, and, at the time of still image shooting, the light amount limiting means and the shutter at the exposure amount specified at the time of previous moving image shooting. It has an exposure control means for performing exposure control of the function.

In order to solve the above problem (2), according to the present invention, the signal processing means further comprises a step of mixing the pixels when the solid-state image pickup device outputs pixel signals independently and a step of mixing and outputting pixels. The video signal is generated by different signal processing when the video signal is present.

[0009]

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

According to the means for solving the above-mentioned problem (2), at the time of capturing a still image, the driving method of the image pickup device is changed to read out the pixel signals without mixing them, and the still image is output to the signal processing circuit. When the video signal is input, the content of the signal processing is switched to a still image.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the drawings.

FIG. 1 is a configuration diagram of an imaging apparatus according to a 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, and 108 is
A mechanical shutter control circuit; 109, an image sensor driving circuit;
110 is a shutter button. FIG. 2 shows a specific example of the image sensor 103. In FIG. 2, reference numeral 201 denotes a photodiode, 202 denotes a vertical CCD, and 203 denotes a horizontal CCD.
And gr, mg, cy, and ye are Photodiode 2.
01 is a color filter arranged on each surface, gr is green, mg is magenta, cy is cyan, and ye is yellow.
Indicates that this is a 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, and is photoelectrically converted by a photo diode 201 disposed on the surface of the image sensor 103, and is vertically converted. The pixels are mixed in the CCD 202 and the horizontal C
Output via the CD 203. The output signal of the image sensor 103 is amplified by the amplifier 104 and the A / D converter 10
5, the video signal is converted into a digital signal,
6 is input. The video signal processing circuit 106 converts the input signal into a video signal such as NTSC and outputs the same, and outputs luminance information of the subject and the like to the camera control circuit 107. The camera control circuit 107 controls the mechanical shutter control circuit 108 based on the luminance information of the subject so that the output of the video signal processing circuit 106 has a desired luminance level, changes the aperture value of the mechanical shutter 102, and And controls the electronic shutter speed of the image sensor 103.

Next, the electronic shutter will be briefly described. FIG. 3 is a diagram schematically illustrating the potential of the image sensor 103. In the figure, reference numeral 301 denotes an image sensor 1
The charge stored in 03, 302 is a read gate, 3
03 is a substrate voltage, 304 is a well, and 305 is a channel stopper. The electric charge photoelectrically converted by the photodiode 201 is transferred to the read gate 602 and the well.
During 604, it is stored as shown. Image sensor 10
When a charge sweeping pulse is supplied from 3 to the image sensor driving circuit 109, the potential of the substrate voltage 303 decreases. Then, as shown in FIG. 4, the potential of the well 304 is lowered in such a manner as to be drawn into the substrate voltage 303. Then, the electric charge 301 is swept away to the portion of the substrate voltage 303. The channel stopper 305 is for preventing electric charge from leaking from the vertical CCD 202 corresponding to an adjacent pixel.

In this configuration, the shutter button 110
By pressing, a shutter close control signal is input from the camera control circuit 107 to the mechanical shutter control circuit 109, and the mechanical shutter 102 is brought into a closed state after a predetermined time by the mechanical shutter control circuit 109. By the time the mechanical shutter 102 is closed, the image sensor 1
03 is input to the image sensor 10 in the same manner as the above operation.
3 is photoelectrically converted by the photodiode 201 disposed in the vertical shutter 3 while the mechanical shutter 102 is in the closed state.
The signal is transferred to the horizontal CCD 203 via D 202, converted into a voltage in synchronization with the horizontal scanning pulse supplied from the image sensor driving circuit 109, and output. At this time, the imaging device 10
No. 3 is a so-called destructive readout in which once a signal is read from the photodiode 201, no signal remains in the photodiode 201, so that if pixel readout, which is a general readout method, is performed, frame information is read. Will be lost.

Hereinafter, the pixel mixture readout will be described. Until the shutter button 110 is pressed, the image sensor 103 mixes and reads two vertically adjacent pixel signals as described in Japanese Patent Application Laid-Open No. 63-114487. Is read.

FIG. 5 shows a vertical transfer pulse at the time of pixel mixed reading and a timing chart of signal charge transfer in the vertical CCD 202. In the figure, when the ternary pulse of the vertical transfer pulse 1 goes high, the ternary pulse of the vertical transfer pulse 3 goes high from the photodiode 201 in the gr and mg rows.
Signal charges are transferred from the photodiodes 201 in the rows y and ye to the vertical CCDs 202, respectively. Vertical CCD 20
2 is transferred to the vertical CC as shown in FIG.
D202 and mixed in the horizontal CCD 203,
Output from the image sensor 103.

However, if the above-described pixel mixture readout is performed at the time of capturing a still image, a resolution corresponding to the number of pixels in the vertical direction of the image sensor 103 cannot be obtained. Perform 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 in which 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 photodiode of the row of gr and mg is used.
Only in the next field, the ternary pulse of the vertical transfer pulse 3 becomes high level, so that the signal charge is transferred only from the photodiode 201 in the row of cy and mg. The signal charges are transferred to the CCD 202. Since all the signal charges transferred to the vertical CCD 202 are transferred to the horizontal CCD 203 in one field period, the signal charges of the adjacent photodiodes 201 are mixed as in the pixel mixed readout method described above. Therefore, one signal can be obtained for one photodiode. Hereinafter, the signal charges transferred to the horizontal CCD 203 are output from the image sensor 103 in synchronization with the horizontal scanning pulse supplied from the drive circuit 105. The output signal of the image sensor 103 is amplified by the amplifier 104, converted to 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 above independent reading,
Exposure amount of the row photodiode of gr and mg, and cy,
In order to equalize the exposure amounts of the photodiodes in the row y, the mechanical shutter 102 must be fully closed at least during the period from the start of exposure for capturing a still image to the end of reading out the signal. . further,
The amount of exposure to the image sensor 103 is determined from immediately after the photodiode 201 of the image sensor 103 in the front field transfers the signal charges photoelectrically converted to the vertical CCD 202 until the mechanical shutter 102 is fully closed.
Is the amount of light incident on.

FIG. 7 is a graph showing the amount of exposure 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 image sensor 1 for one field period
The electric charge accumulated in the memory 03 is read out every field, the exposure amount is calculated from the luminance signal generated by the signal processing circuit, and the aperture of the mechanical shutter 102 is controlled by the mechanical shutter control circuit 109 so as to obtain a predetermined exposure amount. When the electronic shutter is not used, the exposure of the
01 from the time t1 at which the charge transfer to the vertical CCD 202 is performed
To t4, the shutter button 110 is pressed between times t3 and t4.
Exposure for generating a still image is started from 4. 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 capturing a still image, if the mechanical shutter 102 is operated so that the area indicated by B and the area indicated by A, which is the exposure amount during the period from time t4 to t5, become equal, 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 image pickup apparatus shown in FIG. 1 in the first embodiment described above, the noise component in the moving image pickup signal
Phase is different for each field and smoothed by human eyes,
The noise component in the signal was not so noticeable. However, in the case of a still image, since the above-described smoothing is not performed, it is necessary to improve the S / N when capturing a still image as compared with a conventional imaging apparatus that captures a moving image.

The means for improving the S / N is described below with reference to FIG. In the figure, the electric charge photoelectrically converted by the photodiode 201 is transferred to the read gate 302 and we.
It is stored as shown in FIG. At the time of reading a moving image, the potential of the read gate 302 is reduced by the ternary pulse of the vertical transfer pulses 1 and 3 going high once per field, and the electric charge 301
Is transferred to the vertical CCD 202. At this time, the potential of the read gate shown in FIG.
If the value pulse is lowered by the high level, the potential of the readout gate of the vertically adjacent pixel is lowered by the high level of the ternary pulse of the vertical transfer pulse 3. The electric charge 301 read out by the above method is mixed in the vertical CCD 202 with the electric charge which has been photoelectrically converted by an adjacent photodiode above or below. At the time of capturing a still image, only the ternary pulse of the vertical transfer pulse 1 is set to the high level in the first field to start reading, and only the ternary pulse of the vertical transfer pulse 3 is set to the second field. By setting the level to a high level, the electric charge 301 is read out without performing the pixel mixing. At this time,
As long as the electric charge 601 does not overflow from between the readout gate 602 and the well 604, even if a larger amount of electric charge 301 is stored for one pixel than when capturing a moving image, the vertical CCD 2
02 and the horizontal CCD 203 can transfer charges. By accumulating more 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 image pickup apparatus according to the third embodiment of the present invention is common to that of the above-described first embodiment, and will be described with reference to FIG. In addition, description of portions common to the first embodiment is omitted. As described in the above embodiment, when capturing a still image, it is better to make more light incident on the image sensor 103 and to accumulate more charges to achieve S / S
N is advantageous. Hereinafter, the exposure control at the time of capturing a still image will be described with the amount of charge stored in the image sensor 103 set to 1.5 times that at the time of capturing a moving image.

FIG. 8 shows a mechanical shutter 1 according to this embodiment.
FIG. 9 is a diagram showing an exposure amount to the image sensor 103 with respect to an aperture value of 02 and a transfer timing of charges from the photodiode 201 to the vertical CCD 202. In the above-described image pickup apparatus, before starting a still image pickup operation, exposure control similar to that of a general video camera is performed as described in the first embodiment. Here, for simplicity, only three fields are shown for the moving image capturing time, but the length of the moving image capturing time is an arbitrary length until the exposure control is sufficiently stabilized. Is the time until is pressed. If the shutter button 110 is pressed at the time indicated by ts in FIG. 8 after the exposure control of the moving image is stabilized, a shutter-close control signal is input from the camera control circuit 107 to the mechanical shutter control circuit 109, and the shutter is released. The control circuit 108 causes the mechanical shutter 102 to start the closing operation at the beginning of the next field, that is, at time t4. That is, exposure for capturing a still image is started from time t4. At this time, it is assumed that the mechanical shutter 102 changes the aperture value linearly at a constant speed without inertia, and closes in three fields from the current aperture amount. Also, as shown in FIG.
4 and thereafter, the ternary pulses of the vertical transfer pulses 1 and 3 are stopped until the mechanical shutter 102 is closed, and the photodiode 20 is stopped.
The reading of the electric charge from 1 is stopped. According to the above conditions, the exposure amount when capturing a still image, that is, the area indicated by B, is 1.5 times the exposure amount when capturing a moving image, that is, the area indicated by A, as in the first embodiment. The exposure amount 1.5 times the exposure amount during the period from time t3 to time t4 shown in FIG. T4 to t7 by the above method
The light incident on the image sensor 103 during the period is photoelectrically converted and the ternary pulses of the vertical transfer pulses 1 and 3 are set to high level once each at timings t7 and t8 after the mechanical shutter 102 is closed. Output from the image sensor 103 by independent reading. However, since the independent reading was 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. Also, at this time, the signal charge stored in the image sensor 103 is 1.5 times that at the time of capturing a moving image. Therefore, the total amount of signal amplification in the subsequent signal processing can be made 1 / 1.5 times that at the time of capturing a moving image. good.

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

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

The configuration of the image pickup apparatus according to the third embodiment of the present invention is common to those of the above-described first and third embodiments, and will be described with reference to FIG. In addition, description of portions common to the first and third embodiments will be omitted. Also in the present embodiment, the exposure control at the time of capturing a still image will be described with the amount of charge stored in the image sensor 103 set to 1.5 times that at the time of capturing a moving image.

FIG. 9 shows a mechanical shutter 1 according to the present embodiment.
FIG. 9 is a diagram showing an exposure amount to the image sensor 103 with respect to an aperture value of 02 and a transfer timing of electric charges from the photodiode 201 to the vertical CCD 202. The present embodiment is different from the above-described third embodiment in that the illuminance of the subject is higher and the amount of exposure to the image sensor 103 is half that of the above-described third embodiment. In the above-described image pickup apparatus, before starting a still image pickup 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 exposure control of the moving image is stabilized, the exposure for capturing a still image starts at time t4. At this time, the mechanical shutter 102 linearly changes the aperture value at a constant speed without inertia similarly to the third embodiment. That is, the time required for the mechanical shutter 102 to close is also halved, which is 1.5 fields. At this time, as in the first embodiment, assuming that the mechanical shutter 102 is closed from the next field when the shutter button 110 is pressed, that is, from time t4, the exposure amount for capturing a still image is changed to time t.
The exposure amount cannot be set to 1.5 times the exposure amount by the exposure control performed when capturing a moving image from 3 to time t4. Therefore, even if the shutter button 110 is pressed, the camera control circuit 10
7 does not output a shutter-close control signal to the mechanical shutter control circuit 109 for a fixed time determined by the following method.

FIG. 10 shows a series of operations from when the shutter button 110 is pressed to when the camera control circuit 107 calculates the above-mentioned predetermined time and outputs a shutter-close control signal to the mechanical shutter control circuit 109. It is a flowchart. 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 determines the current aperture value of the mechanical shutter 102 from the current aperture value. The time required until the mechanical shutter 102 closes is calculated. Then, it calculates how long the closing operation of the mechanical shutter 102 should be delayed in order to provide an exposure amount 1.5 times the exposure amount by the exposure control performed at the time of capturing a moving image at the time of capturing a still image. After the time obtained by the above calculation after the shutter button 110 is pressed, the camera control circuit 107 supplies the shutter shutter
Then, the mechanical shutter 102 is closed. Although not shown, the camera control circuit 107 has means for recognizing the aperture value of the mechanical shutter 102, and determines the exposure amount to the image sensor 103 based on the current exposure amount and the time required until the mechanical shutter 102 closes. Means is provided for calculating the above-mentioned fixed time required for giving an exposure amount 1.5 times that at the time of capturing a still image as at the time of capturing a moving image. In this embodiment, by setting the above-mentioned fixed time to one field, the exposure amount at the time of capturing a still image shown in FIG. The exposure amount at the time, that is, 1.5 times the area indicated by A, and the exposure amount 1.5 times the exposure amount during the period from time t3 to t4.
Can be given to. The light incident on the image sensor 103 from t4 to the time when the mechanical shutter 102 is closed by the above method is photoelectrically converted, and the vertical transfer pulses 1, 3, 3 are respectively transferred once at timings t7 and t8 after the mechanical shutter 102 is closed. The value pulse is set to a high level and output from the image sensor 103 by the above-described independent reading. However,
Since the independent reading was performed, the video signal processing circuit 106
The signal processing is switched for a still image, and the input signal is converted into a video signal and output. At this time, the image sensor 103
Is 1.5 times as large as that at the time of capturing a moving image, so that the total amount of signal amplification in subsequent signal processing may be set to 1 / 1.5 times that at the time of capturing a moving image.

Further, the video signal imaged from the time t4 until the mechanical shutter 102 closes can be read out only once, and if read out, it is recorded in a recording means such as a memory (not shown), and if necessary, a computer is used. -Output as still images to data devices.

At the time of capturing a still image, it is possible to obtain an exposure amount 1.5 times the exposure amount at the time of capturing a moving image. It is needless to say that, when the subject is brighter and the exposure amount is smaller, the certain time is longer correspondingly. Note that, as in the third embodiment described above,
As shown in FIG. 9, after the time t4, the ternary pulses of the vertical transfer pulses 1 and 3 are stopped until the mechanical shutter 102 closes, and the reading of charges from the photodiode 201 is stopped.

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

This embodiment has portions common to the above-described third embodiment, and different portions will be described. Also in the present embodiment, the exposure control at the time of capturing a still image will be described with the amount of charge stored in the image sensor 103 set to 1.5 times that at the time of capturing a moving image.

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,
FIG. 4 is a diagram showing a timing of transferring charges from the photodiode 201 to the vertical CCD 202 and a timing of a charge sweeping-out pulse supplied from the image sensor 108. The present embodiment is different from the above-described third embodiment in that the illuminance of the subject is lower and the amount of exposure to the image sensor 103 is twice that of the third embodiment. In the above-described image pickup apparatus, before starting a still image pickup 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 exposure control of the moving image is stabilized, the exposure for capturing a still image starts from time t4. At this time, the mechanical shutter 102 linearly changes the aperture value at a constant speed without inertia similarly to the third embodiment.
That is, the time required until the mechanical shutter 102 closes is also doubled, and is six fields. At this time, assuming that the mechanical shutter 102 is closed from the next field in which the shutter button 110 is pressed, that is, from time t4,
The amount of exposure for capturing a still image is three times the amount of exposure performed by the exposure control performed when capturing a moving image from time t3 to time t4. Therefore, while the shutter button 110 is pressed and the mechanical shutter 102 is performing the closing operation from time t4, the camera control circuit 107 uses the electronic shutter function of the image sensor 103 for a certain period of time determined by the following method. The charge stored in the photodiode 201 is swept away.

FIG. 12 shows a series of operations from when the shutter button 110 is pressed to when the camera control circuit 107 calculates the above-mentioned fixed time and outputs a shutter-close control signal to the mechanical shutter control circuit 109. It is a flowchart. 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 determines the current aperture value of the mechanical shutter 102 from the current aperture value. The time required until the mechanical shutter 102 closes is calculated. Then, in order to give an exposure amount 1.5 times the exposure amount by the exposure control performed at the time of capturing a moving image at the time of capturing a still image, it is calculated how much charge should be discharged from the electronic shutter function from time t4. . After the shutter button 110 is pressed, the camera control circuit 107 outputs a shutter-close control signal to the mechanical shutter control circuit 109 to close the mechanical shutter 102 from time t4, and simultaneously obtains the time obtained by the above calculation. The image sensor driving circuit 108 is controlled to supply a charge sweeping pulse to the image sensor 103. Although not shown, the camera control circuit 107 has means for recognizing the aperture value of the mechanical shutter 102, and determines the current exposure amount and the mechanical shutter 10
There is provided a means for calculating the above-mentioned fixed time required to give the exposure amount to the image sensor 103 at the time of capturing a still image 1.5 times the exposure amount at the time of capturing a moving image from the time required until the shutter 2 closes. In this embodiment, by setting the above-mentioned fixed time to approximately two fields, it is possible to obtain an exposure amount 1.5 times as large as the exposure amount at the time of capturing a moving image at the time of capturing a still image. It is needless to say that, when the subject is darker and the exposure amount is larger, the certain time is longer correspondingly.

Further, since the video signal imaged from the time t4 to when the mechanical shutter 102 closes can be read out only once, when it is read out, it is recorded in a recording means such as a memory (not shown). Output as a still image to a data device or the like. Note that, as in the third embodiment, as shown in FIG.
The ternary pulses of the vertical transfer pulses 1 and 3 are stopped until 02 is closed, and the reading of charges from the photodiode 201 is stopped.

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

FIG. 13 is a block diagram of an image pickup apparatus according to the embodiment of the present invention. The same reference numerals as in the first embodiment denote the same parts, and a description thereof will be omitted. In FIG.
Reference numeral 01 denotes a mechanical shutter, and 1302, an EEPROM (electrically rewritable ROM). In the above-described third, fourth, and fifth embodiments, the mechanical shutter 102 has an aperture value that has no inertia and has a constant linear speed at a constant speed. The mechanical shutter 1301 has inertia, though it is assumed to change. 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 109 follows the locus shown in FIG. The locus shown in FIG. 14 differs depending on the type of the mechanical shutter 1301,
Further, even the same type of mechanical shutter is not necessarily the same due to individual variations and the like. Therefore, the locus of the used mechanical shutter 1301 during the closing operation is stored in the EEPROM 1302.
Is recorded in advance. FIG. 14 shows a mechanical shutter 130.
Although only three types of aperture values are shown, the locus of the closing operation of the mechanical shutter 1301 at each arbitrary aperture value is recorded in the EEPROM 1302 as needed. The data recorded in the EEPROM 1302 may be recorded at the time of automatic adjustment in the production process.

The trajectory of the closing operation of the mechanical shutter 1301 at each of the above-mentioned arbitrary aperture values may be recorded in other recording means.

Hereinafter, the exposure control at the time of capturing a still image in this embodiment will be described. Before performing the still image capturing operation in the same manner as in the first, third, fourth, and fifth embodiments, a moving image similar to that of a general video camera is captured, and the exposure control performed by the general video camera is performed. Perform Figures 15, 16, 17
In the present embodiment, the exposure amount of the mechanical shutter 1301 with respect to the aperture value of the mechanical shutter 1301 and the amount of exposure to the image sensor 103 and the vertical CCD 202
FIG. 18 is a diagram showing the transfer timing of charges to
9 is a flowchart illustrating an exposure control operation at the time of capturing a still image after the shutter button 110 is pressed.

As shown in FIG. 18, after the exposure control of the moving image is stabilized, the shutter button 11 is released at an arbitrary timing ts.
When 0 is pressed, the camera control device 107 sets the trajectory of the closing operation corresponding to the current aperture value of the mechanical shutter 1301 to E
Read from EPROM. Then, based on the data from the EEPROM, at the time of capturing a still image, in order to give an exposure amount 1.5 times the exposure amount by the exposure control performed at the time of capturing a moving image, as shown in FIG. Using a method of delaying the shutter closing operation performed in the fourth embodiment,
In addition, as shown in FIG. 16, electric charges are discharged by the electronic shutter performed in the fifth embodiment described above.
As shown in FIG. 7, it is determined whether the shutter closing operation is to be performed from time t4 as performed in the third embodiment. If the result of the determination is that the shutter closing operation is delayed as in the fourth embodiment, the camera control circuit 1
07 selects a shown in FIG. 18 and calculates how much the shutter closing operation is delayed from time t4. After a calculation time obtained from time t4, that is, at time tss shown in FIG. Is output to the mechanical shutter control circuit. If the result of the determination is that the electric shutter is to be used to discharge electric charges in the same manner as in the fifth embodiment, b shown in FIG.
7 is time t4 which is an exposure start time for capturing a still image
Calculates the time for discharging the electric charges by the electronic shutter, and outputs a shutter-close control signal to the mechanical shutter control circuit 109 at time t4, and simultaneously controls the image sensor driving circuit 108 for the time obtained by the above calculation. Then, the charge accumulated in the image sensor 103 is swept out. In addition to the above two cases, that is, when it is not necessary to delay the shutter closing operation or to perform the sweeping out of the electric charge by the electronic shutter, c shown in FIG. 18 is selected, and as in the third embodiment described above. From time t4 to shutter
Output to the mechanical shutter control circuit 109,
The mechanical shutter 1301 is closed.

Although not shown, the camera control circuit 10
Numeral 7 has a means for recognizing the aperture value of the mechanical shutter 1301. Based on the current exposure amount and the data supplied from the EEPROM 1302, the exposure amount to the image sensor 103 is set to 1.5 times when capturing a still image and when capturing a moving image. Means for determining whether any of the above methods should be used in order to double the number;
It has means for calculating the time for delaying the shutter closing operation and means for calculating the time for discharging the electric charge by the electronic shutter. Further, since the video signal imaged from the time t4 until the mechanical shutter 1301 closes can be read out only once, when read out, it is recorded in a recording means such as a memory (not shown), and if necessary, a computer device is used. 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 after the time t4 until the mechanical shutter 102 closes as shown in FIGS. The reading of charges from the node 201 is stopped.

[0043]

According to the present invention, it is possible to provide an imaging apparatus capable of performing accurate exposure control at the time of capturing a still image and capturing a high-quality still image.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a circuit configuration of an imaging device according to an embodiment of the present invention.

FIG. 2 is a diagram illustrating a specific example of an image sensor according to an embodiment of the present invention.

FIG. 3 is a diagram illustrating a potential of the image sensor according to the embodiment of the present invention.

FIG. 4 is a diagram illustrating a potential of the image sensor according to the embodiment of the present invention.

FIG. 5 is a timing chart showing driving of the image sensor according to the embodiment of the present invention.

FIG. 6 is a timing chart showing driving of the image sensor according to the embodiment of the present invention.

FIG. 7 is a diagram illustrating an exposure amount to an image sensor according to the embodiment of the present invention.

FIG. 8 is a diagram illustrating an exposure amount to an image sensor and driving of the image sensor according to the embodiment of the present invention.

FIG. 9 is a diagram illustrating an exposure amount to an image sensor and driving of the image sensor according to the embodiment of the present invention.

FIG. 10 is a flowchart according to an embodiment of the present invention.

FIG. 11 is a diagram illustrating an exposure amount to an image sensor and driving of the image sensor according to the embodiment of the present invention.

FIG. 12 is a flowchart according to an embodiment of the present invention.

FIG. 13 is a block diagram illustrating a circuit configuration of the imaging device according to the embodiment of the present invention.

FIG. 14 is a diagram illustrating a trajectory of a closing operation of the mechanical shutter according to the embodiment of the present invention.

FIG. 15 is a diagram illustrating an exposure amount to an image sensor and driving of the image sensor according to the embodiment of the present invention.

FIG. 16 is a diagram illustrating an exposure amount to an image sensor and driving of the image sensor according to the embodiment of the present invention.

FIG. 17 is a diagram illustrating an exposure amount to an image sensor and driving of the image sensor according to the embodiment of the present invention.

FIG. 18 is a flowchart according to an embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 101 ... Lens 102 ... Mechanical shutter 103 ... Image sensor 104 ... Amplifier 105 ... A / D converter 106 ... Video signal processing circuit 107 ... Camera control circuit 108 ... Mechanical shutter control circuit 109 ... Image sensor drive circuit 110 ... Shutter button 201 ... Photo diode C. 202 202 Vertical CCD 203 Horizontal CCD 301 Charge 302 Readout gate 303 Substrate voltage 304 Well 305 Channel stopper 1301 Mechanical shutter 1302 EEPROM

──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Naoki Yamamoto 1410 Inada, Katsuta, Ibaraki Pref. AV Equipment Division, Hitachi, Ltd. (56) References JP, 60-143073 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) H04N 5/235-5/243 H04N 5 / 335

Claims (2)

(57) [Claims] (1)Light amount limiting means for blocking a part of incident light
When, The incident light is photoelectrically converted for each pixel, and
Shutter that sweeps away photoelectrically converted charges at any time
A solid-state imaging device having a function; The signal photoelectrically converted by the solid-state imaging device is used as a video signal.
Signal processing means for outputting; The light amount limiting means and the shutter function of the solid-state imaging device.
Exposure control means for adjusting the amount of exposure by controlling, The exposure control is performed so that the light quantity limiting means blocks incident light.
Control means for controlling incident light blocking means, The exposure control means controls incident light from the incident light control means.
Receiving the cutoff control, the light amount limiting means is operated to block the incident light.
At least the light quantity limiting means from the field in which the operation is performed.
The solid-state imaging device
Control so that the child does not output the photoelectrically converted charge, The incident light blocking control is input from the incident light blocking control means.
Incident light from the incident light blocking control means
In order to increase the exposure amount after the cutoff control is input,
Controlling the light quantity limiting means and the shutter function.
An image pickup device. (2)Light amount limiting means for blocking a part of incident light
When, The incident light is photoelectrically converted for each pixel, and
Shutter that sweeps away photoelectrically converted charges at any time
A solid-state imaging device having a function; The signal photoelectrically converted by the solid-state imaging device is used as a video signal.
Signal processing means for outputting; The light amount limiting means and the shutter function of the solid-state imaging device.
Exposure control means for adjusting the amount of exposure by controlling, The exposure control is performed so that the light quantity limiting means blocks incident light.
Control means for controlling incident light blocking means, The exposure control means controls incident light from the incident light control means.
Receiving the cutoff control, the light amount limiting means is operated to block the incident light.
At least the amount of light from the field Limiting means
The solid-state imaging device
Control so that the child does not output the photoelectrically converted charge, The signal processing means may be configured such that the solid-state imaging device processes a signal of a pixel.
When outputting independently and when mixing and outputting pixels
Generating video signals by different signal processing at different times
An imaging device characterized by the above-mentioned.