JPH11205690A - Digital still camera - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a high quality image even at a fast shutter speed by storing smear data that includes a smear component for at least one horizontal line, performing a correction operation to an image pickup output signal that is read from an imaging device by using the smear data and eliminating smear components in the image pickup signal. SOLUTION: In a mode that performs smear correction, a read gate pulse which is outputted every 1/60 second is forcedly turned off, and an image pickup output signal that is obtained does not include a signal charge component which is stored in a photoelectric element but includes only a smear component that is leaked to vertical transfer. At least data for one horizontal line in the smear component is temporarily stored in internal memory of a CPU 34. A digital signal processing circuit 20 performs operation processing based on fetched data and the smear data stored in the CPU internal memory and eliminates smear components from the fetched image data. Data that undergoes correction processing is preserved in a recording medium 30.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a digital still camera, and more particularly to a digital still camera having a function of preventing image quality deterioration due to smear.

[0002]

2. Description of the Related Art When a high-luminance subject such as the sun or a light is photographed by a camera using a solid-state imaging device such as an interline (IL) system or a frame transfer (FT) system, a band-shaped bright line is formed in the vertical direction of a photographing screen. Appears. Such a phenomenon is called a smear phenomenon, and when a charge generated in each photodiode (photoelectric conversion element) of the surface imaging device is transferred and read by the transfer register, a charge of a large incident light amount overflows to the transfer line, or This is caused by the fact that the incident light itself leaks into the transfer line and generates charges on the transfer line.

In order to reduce or eliminate the smear phenomenon, in a conventional CCD camera, the amount of incident light itself has been limited by an electronic shutter or an aperture mechanism. Further, a method of removing a smear component generated in an imaging device by electrical processing has been proposed (Japanese Patent Application Laid-Open Nos. 59-62272, 59-62272, and 5-733).
No. 5).

[0004]

However, in the case of a camera in which the amount of incident light is controlled by a combination of an electronic shutter and an aperture, when an excessive amount of light enters, the electronic shutter is set to a high-speed side in response to the incident light. There is a problem that the ratio of the smear component increases and the final image quality deteriorates. Therefore, the speed of the electronic shutter cannot be increased to a certain level or higher, and the control of the amount of light by a mechanical aperture is required beyond that. For this reason, it is necessary to provide an aperture adjusting means, and there is a disadvantage that the mechanism is complicated and the cost is high.

The smear correction method disclosed in Japanese Patent Application Laid-Open No. 59-62272 and Japanese Patent Application Laid-Open No. 59-62272 discloses a photoelectric conversion element of a part of a surface imaging device for obtaining data of a smear component. Must be light-shielded, and more photoelectric conversion elements than the number of effective pixels are required for the light-shielding lines, and there is a disadvantage that the configuration of the solid-state imaging device is complicated and large.

Actually, the area that can be shielded from light in an imaging device is about one or two lines (at most several lines), and the information that can be obtained as smear data is limited to the information for these several lines. However, there is a disadvantage that the accuracy of smear correction is low. On the other hand, the electronic still camera disclosed in Japanese Patent Application Laid-Open No. Hei 5-7335 performs smear correction on photometric data when obtaining a photometric value, so that a smear component included in an image signal to be recorded is completely eliminated. Has the disadvantage that it cannot be removed.

SUMMARY OF THE INVENTION The present invention has been made in view of such circumstances, and does not require a mechanical aperture adjustment mechanism, and has a smear correction function capable of acquiring a high-quality image even at the time of a high-speed shutter. The purpose is to provide a camera.

[0008]

According to a first aspect of the present invention, there is provided a digital still camera according to the first aspect.
An image pickup element in which photoelectric conversion elements are two-dimensionally arranged and having a vertical transfer unit and a horizontal transfer unit for transferring signal charges accumulated in each photoelectric conversion element; a driving circuit for driving the image pickup element; An exposure control unit that discharges unnecessary charges stored in the photoelectric conversion element, controls exposure by controlling a charge storage time by the photoelectric conversion element, and an imaging output signal read from the imaging element. A to digitize
A / D converter, a signal processing circuit for processing data output from the A / D converter, and recording for recording image data processed by the signal processing circuit on a recording medium in response to input of a shooting start signal Means for turning off the read gate pulse for reading the signal charge accumulated in the photoelectric conversion element, and driving and driving the vertical transfer unit and the horizontal transfer unit to correspond to the charge remaining in the vertical transfer unit. Drive circuit control means for controlling the drive circuit to output a smear component to be output from the image sensor, storage means for storing smear data including at least one horizontal line of smear components, and application of a read gate pulse. The imaging output signal read from the imaging device is subjected to a correction operation using the smear data stored in the storage unit, and is included in the imaging output signal. It is characterized by comprising: a smear correction operation circuit for removing smear component, the.

According to the present invention, in order to obtain information on the smear component leaked into the vertical transfer section of the image pickup device, the readout gate pulse applied to the image pickup device is turned off, and the signal charge accumulated in the photoelectric conversion element is turned off. The transfer of the vertical transfer unit and the horizontal transfer unit is performed without transferring to the vertical transfer unit. The imaging output signal output from the imaging device in this manner does not include a signal charge component due to the photoelectric conversion element, but includes only a charge component (smear component) remaining in the vertical transfer unit. This is stored in the storage means as smear data and used for smear correction calculation.

Since smear appears with a substantially uniform intensity in the vertical line direction of the image sensor, if smear data is obtained in at least one horizontal line direction of the image sensor, a smear correction operation can be performed. In this regard, in the present invention, smear components for the entire screen can be acquired, and more accurate smear correction can be performed in consideration of the smear components of the entire screen.

In addition, the present invention focuses on the point that smear becomes a problem only when an excessive amount of light enters, and the invention according to claim 2 is an electronic shutter based on photometric calculation in a camera having an automatic exposure control function using a so-called electronic shutter. When the value is set faster than the predetermined value, the read gate pulse is turned off and smear data is obtained. Then, a smear correction calculation is performed using the smear data.
In this way, by automatically determining the necessity of smear correction according to the electronic shutter value and performing smear correction,
Arithmetic processing can be simplified.

According to another aspect of the present invention, when the electronic shutter value based on the photometry calculation is set to be faster than a predetermined value, the photographer himself can correct the smear. A means may be provided for selecting whether or not to perform and inputting the instruction. Then, a mode is also possible in which the read gate pulse is turned off in accordance with the selection instructed by such means, and smear data is obtained.

In a digital still camera, it is most important to perform smear correction on image data recorded in response to the input of a shooting start signal. During the input standby period, the read gate pulse may be periodically turned off to obtain smear data. In this manner, the smear data is periodically taken in, and rewritten and updated sequentially with new smear data, so that smear correction can be performed using the latest smear data for the input of the shooting start signal.

According to a fifth aspect of the present invention, a smear phenomenon that occurs in a pixel unit of an image sensor is corrected in a photometric area unit, and is replaced with a storage unit and a smear correction calculation circuit in a digital still camera according to the first aspect. The light receiving area of the image sensor is divided into a plurality of photometric areas in advance,
Using the divided photometric calculation means for acquiring photometric information for each photometric area, and smear data including a smear component of one entire screen using the divided photometric calculation means, and obtaining smear correction data for each of the photometric areas. Correction data obtaining means, storage means for storing the smear correction data obtained by the smear correction data obtaining means, and for the imaging output signal read by the read gate pulse, using the smear correction data stored in the storage means. A smear correction calculation circuit for performing a correction calculation in units of photometric areas and removing a smear component included in the imaging output signal.

According to the present invention, the divided photometric operation means for performing arithmetic processing on the image pickup output signal from the image sensor for each photometric area is also used for smear correction, and smear correction data is obtained for each photometric area. Smear correction is applied in units. As a result, arithmetic processing can be simplified.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of a digital still camera according to the present invention will be described below in detail with reference to the accompanying drawings. FIG. 1 is a block diagram showing a configuration of a digital still camera according to the present invention. The digital still camera 10 mainly includes a photographing lens 12 and a solid-state imaging device 1.
4, analog signal processing circuit 16, A / D converter 18, digital signal processing circuit 20, frame memory 22, display memory 24, D / A converter 26, liquid crystal display (L
A display unit 28 such as a CD), a recording medium 30, an operation unit 32, a central processing unit (CPU) 34, and the like.

The photographing lens 12 is composed of one or a plurality of lenses, and may be a lens having a single focal length (fixed focus) or a variable focal length lens such as a zoom lens or a step zoom lens. As the solid-state imaging device 14, a known two-dimensional imaging device (plane imaging device) is used. Generally, imaging devices are CCD type, MOS type, C type
ID types can be roughly classified into three types, and particularly widely used CCD types can be further classified into two types: an interline type and a frame transfer type. Although any type of imaging device may be employed, in the present embodiment, a photoelectric conversion element (photo sensor)
Are arranged two-dimensionally, and an interline CCD image pickup device in which signal charges accumulated in each sensor are output via a vertical transfer unit and a horizontal transfer unit (see FIG. 2).

As will be described later in detail, the solid-state image pickup device 14 is provided with a sweep drain for discharging unnecessary charges, and drives the readout gate by a shutter gate pulse to reduce the signal charges accumulated in each sensor. It can be drained to the drain. That is, this imaging device has a so-called electronic shutter function of controlling the accumulation time (shutter speed) of the electric charge accumulated in each sensor by the shutter gate pulse.

A solid-state image pickup device 14 via a photographing lens 12
The subject image formed on the light receiving surface is converted into a signal charge of an amount corresponding to the amount of incident light by each sensor, sequentially read out as an imaging output signal, and then supplied to the analog signal processing circuit 16. . The analog processing circuit 20 includes a CDS clamp circuit, a gain adjustment circuit, a gamma correction circuit, and the like, and appropriately processes an imaging output signal (analog electric signal) input from the solid-state imaging device 14 based on the control of the automatic system control circuit 36. . After the signal output from the analog signal processing circuit 16 is converted into a digital signal by the A / D converter 18, the digital signal processing circuit 20 and the automatic system operation circuit 3
It is led to 8.

The automatic operation circuit 38 includes an A / D converter 1
8 and the exposure value is calculated based on the imaging output signal (R, G, B digital signal) for one frame obtained from
The gain value of the RGB signal is calculated so that each signal level of RGB is matched. For example, R, B based on G signal
When matching the signal levels, the RB gain value is calculated. The exposure value and the gain value thus obtained are notified to the automatic control circuit 36.

The auto system control circuit 36 controls auto focus, automatic exposure control, auto strobe, auto white balance, etc., and controls the image pickup drive circuit 40 according to the exposure value input from the auto system operation circuit 38. , The charge storage time of the solid-state imaging device 14, that is, the electronic shutter value is set. Also, the automatic system control circuit 36
Controls the analog signal processing circuit 16 in accordance with the RB gain value input from the automatic operation circuit 38, and sets the white balance. Thus, the exposure control of the camera is automatically performed.

On the other hand, the digital signal processing circuit 20 includes a luminance signal generation circuit, a color difference signal generation circuit, a compression / decompression circuit, and the like, and generates image data of a photographed image based on a signal input from the A / D converter 18. I do. The data processed by the digital signal processing circuit 20 is supplied to a display memory 24, and the image data stored in the display memory 24 is
After being converted into an analog signal by the A converter 26, the display unit 2
8 is supplied. Thus, the captured image is displayed on the display unit 28. The display unit 28 displays a still image photographed based on a photographing start signal generated by pressing a shutter button or the like included in the operation unit 32, and also displays a video (moving image, moving image, Or intermittent)
Is also displayed.

The image data obtained in response to the input of the photographing start signal is processed by the digital signal processing circuit 20,
It is stored in the frame memory 22. Then, the image data stored in the frame memory 22 is supplied to the recording medium 30 via the CPU 34, and the captured image is recorded and stored in the recording medium 30. The recording medium 30 can take various forms such as a built-in memory of a camera, a removable external storage medium such as a smart media or an IC card, or the like.

The image data stored in the recording medium 30 is a CP
Calling is possible via U34, and the called image data is supplied to the digital signal processing circuit 20 and reproduced in the digital signal processing circuit 20. The signal subjected to the reproduction processing is supplied to the display memory 24, the D / A converter 2
The signal is output to the display unit 28 via the display unit 6 or supplied to a video signal output terminal or the like (not shown) and can be output to another external device.

The CPU 34 is connected to the image pickup drive circuit 40, the automatic system operation circuit 38, the digital signal processing circuit 20, the frame memory 22, the recording medium 30, and the like. Performs calculations and comprehensively manages controls such as automatic exposure control, auto focus, auto strobe, and auto white balance. Further, the CPU 34 controls a corresponding circuit based on various input signals input from the operation unit 32.

The autofocus means can take various forms. For example, a focus evaluation value indicating the sharpness of a subject image is calculated from an image signal, and the focus position is calculated based on the focus evaluation value. . Then, the photographing lens 12 is controlled via a focus drive circuit (not shown) according to the calculated focus position, and the focus position is set. In addition, a known distance measuring unit such as an AF sensor may be used.

In this embodiment, the exposure control is performed based on the video signal obtained by the solid-state imaging device. However, a photometric sensor may be separately provided. FIG. 2 shows a configuration example of an interline CCD imaging device. Although the number of pixels is reduced for the sake of convenience in the drawing, there are actually hundreds of thousands of pixels, and more than one million pixels in high-end ones.

Interline type CCD image pickup device 42
Is a photoelectric conversion element 44, a read gate 46, a vertical transfer CC
D (corresponding to a vertical transfer unit) 48, a drain 50, a horizontal transfer CCD (corresponding to a horizontal transfer unit) 52, an output unit 54, and the like. The photoelectric conversion elements 44 are two-dimensionally arranged by the number of pixels, and the photoelectric conversion elements 44 and the vertical transfer CCDs 48 are alternately arranged for each column in the vertical direction in the figure. Then, each photoelectric conversion element 44 receives the vertical transfer signal C through the read gate 46.
It is connected to CD48.

The uppermost stage of the vertical transfer CCD 48 is connected to the drain 50, and the last stage (the lowermost stage in the figure) is connected to the horizontal transfer CCD 52. And horizontal transfer CCD
The final stage 52 (the leftmost stage in FIG. 2) is connected to an output unit 54, and an output signal from the output unit 54 is taken out from an output terminal 56. The read gate 46 is controlled by a read gate pulse or a shutter gate pulse given from the imaging drive circuit 40 described with reference to FIG. 1, and is stored in the photoelectric conversion element 44 when the read gate pulse or the shutter gate pulse is applied. Signal charge is transferred vertically
8 is read.

The vertical transfer CCD 48 includes an image pickup driving circuit 40
Signal charge by vertical transfer pulse applied from
Vertical transfer upward or downward. That is, the unnecessary charge (the charge transferred to the vertical transfer CCD by the application of the shutter gate pulse) when performing the shutter operation is
After being read out by the vertical transfer CCD 48, it is transferred at a high speed in the upward direction (reverse direction) in FIG. When an image pickup device is used instead of providing the sweeping drain 50, in which unnecessary charges are swept to the CCD substrate in the same manner as in the vertical overflow drain (VOFD), the vertical transfer C is performed in the sweeping of the unnecessary charges.
There is no need to use the reverse transfer of CD48.

On the other hand, the signal charges accumulated for a predetermined charge accumulation time indicated by the electronic shutter value are read out by the vertical transfer CCD 48 and then transferred in the direction of the horizontal transfer CCD 52 (downward in FIG. 2). The signal charges transferred to the last stage of the vertical transfer CCD 48 are sequentially transferred to the horizontal transfer CCD 52 every horizontal retrace period. The horizontal transfer CCD 52
The signal charges are transferred to the output unit 54 by a horizontal transfer pulse applied from the imaging drive circuit 40. The output unit 54 detects the charge of the input signal charge and outputs the signal charge to the output terminal 56 as a signal voltage.

Vertical transfer CCD 48 and horizontal transfer CCD 5
Reference numeral 2 denotes a vertical transfer CCD, which is shielded from light by a light-shielding member (not shown).
48 leaks and induces a smear phenomenon. The means for smear correction employed in the present embodiment to reduce and remove this smear will be described below.

When light from a subject enters the light receiving surface of the solid-state imaging device 14 through the photographing lens 12, a signal charge corresponding to the intensity of the light incident on that portion is gradually generated in each photoelectric conversion element 44. . In this manner, the signal charges accumulated for a certain period of time are simultaneously transferred to the vertical transfer CCD 48 by the read gate pulse applied from the image pickup drive circuit 40, and are vertically transferred by application of the vertical transfer pulse. The signal charge transferred to the final stage of the vertical transfer CCD 48 is transferred to the horizontal transfer CCD 52, and is taken out as a signal voltage via the output unit 54 by applying a horizontal transfer pulse.

Normally, as shown in the timing chart of FIG. 3, the imaging drive circuit 40 generates a vertical drive pulse (VD) having a period of one vertical period (one field period = 1/60 second in the case of the NTSC system). A synchronized read gate pulse is output, and an image pickup output signal is read every 1/60 second. In this case, if the electronic shutter value is set to a higher speed than 1/60 second in accordance with the calculation of the exposure value, the shutter gate pulse for discharging the unnecessary charge is applied to the read gate 46 before the application of the read gate pulse. And unnecessary charges are discharged to the sweep drain 50 by the reverse transfer of the vertical transfer CCD 48. Then, the signal charges accumulated during the predetermined charge accumulation time indicated by the electronic shutter value are read by the read gate pulse.

On the other hand, in the mode for performing smear correction (smear measurement mode), as shown in FIG. 4, the read-out gate pulse output every 1/60 second is forcibly turned off, and the photoelectric conversion is performed. Only the vertical transfer CCD 48 and the horizontal transfer CCD 52 are driven without transferring the signal charges of the conversion element 44 to the vertical transfer CCD 48, and an output signal is taken out from the output unit 54.

As described above, the image pickup output signal obtained with the read gate pulse turned off does not include the component of the signal charge accumulated in the photoelectric conversion element 44, but includes only the smear component leaked into the vertical transfer CCD 48. Have been. Among the data of only the smear component (hereinafter referred to as smear data), data of at least one horizontal line (one horizontal line pixel of the imaging device 42) is temporarily stored in the internal memory of the CPU 34 or other storage means. I do. And
As shown in FIG. 5, in the next vertical drive cycle, a read gate pulse is added in synchronization with the vertical drive pulse, and actual image capture is performed. For example, when reading an image for recording of a VGA size, data for one frame is read out in 1/30 second.

The image data thus fetched and C
The digital signal processing circuit 20 performs arithmetic processing based on the smear data stored in the internal memory of the PU 34,
The smear component is removed from the captured image data. The image data subjected to the smear correction processing can be stored in the recording medium 30 and can be displayed on the display unit 28.
By performing such smear correction, it is possible to obtain a high-quality image with a good color balance.

After the image data is fetched in the recording mode shown in FIG. 5, the image pickup output signal is read out every 1/60 second according to the timing chart shown in FIG. FIG. 6 is a diagram showing a flow of mode control during the above-described series of photographing operations, where A is the photometry mode described in FIG. 3, B is the smear measurement mode described in FIG. 4, and C is FIG. Indicates the recording mode described.

As shown in FIG. 6, when the photographing start signal is input, the photometry processing in the photometry mode (A) is repeated three times, the photometry calculation is determined, and then the mode shifts to the smear measurement mode (B) to transmit the smear data. Get. After that, the mode shifts to the recording mode (C), the image data for one frame is fetched, and the image data is subjected to smear correction. After capturing one frame of image data in the recording mode, the process returns to the photometry mode (A). Such mode switching is performed by the CPU.
34.

Since a digital still camera is intended to record a still image, it is sufficient that at least the image to be recorded and stored is of high image quality. Unlike a video camera, a digital still camera captures an image captured by the solid-state image sensor 14. It is not required to always display (in real time) with high image quality. Therefore, it is possible to adopt a method in which the read gate pulse is turned off immediately before recording an image in accordance with the input of the shooting start signal, smear data is acquired as described above, and smear correction is performed on at least the recorded image. it can.

Further, the present invention is not limited to the mode in which the smear data is obtained in response to the input of the photographing start signal. The smear data may be obtained periodically at a predetermined cycle while displaying a moving image (monitor mode). For example, as shown in FIG. 7, a sequence is set such that the read pulse is turned off once every three vertical driving cycles, and smear data is periodically acquired. Then, first, the photometric mode is set and 1
A read gate pulse is applied every / 60 seconds, and a process for reading image data (symbol A) is executed three times. After that, the mode is switched to the smear measurement mode, the read gate pulse is turned off, and the vertical transfer CCD 48 remains. The reading process of only the smear data is performed (reference B). In this way, new smear data is acquired periodically, and each time it is rewritten and updated with the latest smear data.

When an input of a shooting start signal is received in the middle of the monitor mode, smear correction is performed on a recorded image using the latest smear data acquired most recently. In addition to the above-described embodiment, smear correction may be automatically performed according to the electronic shutter value. The problem of image degradation due to smear is a problem only when an excessive amount of light is incident on the solid-state imaging device 14. In such a case, it is sufficient to effectively operate the smear correction function.

For this purpose, it is determined from the electronic shutter value set by the automatic exposure control function whether or not an excessive amount of light has entered the solid-state imaging device 14, and the electronic shutter value is set to a predetermined value (smear generation). It is preferable that the above-described acquisition of the smear data and the execution of the smear correction process are performed only when the speed is set to a higher speed than the electronic shutter value which is a concern.

Alternatively, when the electronic shutter value is set to a value higher than the predetermined value on the high-speed side, the photographer is warned by displaying the possibility of occurrence of smear on the display unit 28, for example. May be performed, and whether to perform smear correction or not may be selected according to the photographer's own judgment. In this case, when an instruction to perform smear correction is input by a selection unit (not shown), the above-described read gate pulse is turned off, the smear data is fetched, and the next vertical drive is performed using the smear data. Smear correction is performed on the image taken in the cycle.

In the above embodiment, the case where smear data for one horizontal line is stored and used as smear correction data has been described. However, it is necessary to acquire smear data for at least one horizontal line. Smear components for two or more lines or a whole screen may be acquired, and a value obtained by averaging them may be used as smear correction data.

When acquiring smear data and performing smear correction, a photometric area in exposure control may be used. For example, as shown in FIG.
A case where the photometric area A11, A12,..., A44 is divided into 16 sections will be described as an example. In the case where the read gate pulse is stopped (turned off) to obtain smear data, one of the solid-state imaging devices 14 is used. Capture the smear component of the whole screen.

At this time, the data is integrated for each photometric area with the help of the photometric calculation circuit, and smear data for each photometric area is obtained. Then, the smear data calculated for each photometry area is stored in the internal memory of the CPU 34 or the like. And
Using the obtained smear data for each photometry area, smear correction is performed for each row of the photometry area. In the case of the division form shown in FIG. 8, the area is divided into four regions in the horizontal direction such as a first column, a second column, a third column, and a fourth column in order from the left. Correction is performed.

If the smear data of at least four photometry areas arranged in the horizontal direction among the 4 × 4 photometry areas are stored, the calculation of the smear correction can be performed. Storing the smear data of the area enables more accurate smear correction. The manner of dividing the photometric area is not limited to that shown in FIG. 8, and even when one screen is divided into finer photometric areas, smear correction can be performed in units of photometric areas as described above.

[0049]

As described above, according to the digital still camera of the present invention, the read gate pulse applied to the image pickup device is turned off, and only the vertical transfer unit and the horizontal transfer unit are driven to transfer the smear data. Since the information is acquired, it is not necessary to shield the photoelectric conversion element unit as in the related art.
Further, since smear correction is performed on an image for recording using smear data obtained by such a method, a high-quality image with a good color balance can be obtained. In particular, according to the present invention, it is possible to capture the smear component of the entire screen corresponding to all the pixels of the image sensor, and to perform more accurate smear correction.

Further, according to the digital still camera of the present invention, even when the electronic shutter value is set at a high speed, the smear can be removed by the calculation with the smear data obtained by stopping the read gate pulse. Therefore, a high-quality image can be obtained even at the time of a high-speed shutter. Moreover, the digital still camera according to the present invention does not require any mechanical diaphragm adjusting means as in the related art, and can simplify the mechanism and reduce the cost.

[Brief description of the drawings]

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

FIG. 2 is a schematic diagram illustrating a configuration example of a two-dimensional imaging device.

FIG. 3 is a timing chart of a read gate pulse in a photometry mode.

FIG. 4 is a timing chart of a read gate pulse in the smear measurement mode.

FIG. 5 is a timing chart of a read gate pulse in a recording mode.

FIG. 6 is a diagram showing an example of a mode switching timing.

FIG. 7 is a diagram showing an example of another timing of mode switching.

FIG. 8 is a diagram showing an example of a division mode of a photometry area used for describing a method of performing smear correction for each divisional photometry area.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 12 ... Photographing lens 14 ... Solid-state image sensor 18 ... A / D converter 20 ... Digital signal processing circuit 28 ... Display unit 30 ... Recording medium 38 ... Auto system arithmetic circuit 40 ... Image pickup drive circuit 44 ... Photoelectric conversion element 46 ... Readout gate 48: vertical transfer CCD 50: sweep drain 52: horizontal transfer CCD

Claims (5)

[Claims] 1. An image pickup device in which photoelectric conversion elements are two-dimensionally arranged and have a vertical transfer unit and a horizontal transfer unit for transferring signal charges accumulated in each photoelectric conversion element, and a drive for driving the image pickup device A circuit, based on photometric operation, discharges unnecessary charges accumulated in the photoelectric conversion element, controls exposure time by controlling charge accumulation time by the photoelectric conversion element, and exposure control means, which is read from the imaging element. A / D converter for digitizing the captured image output signal, a signal processing circuit for processing data output from the A / D converter, and inputting a shooting start signal for image data processed by the signal processing circuit Recording means for recording on a recording medium according to the following, and turning off a read gate pulse for reading out signal charges accumulated in the photoelectric conversion element, and transferring and driving the vertical transfer unit and the horizontal transfer unit A driving circuit control means for controlling the driving circuit so as to output a smear component corresponding to the charge remaining in the vertical transfer unit from the image sensor; and smear data including smear components for at least one horizontal line. And a correction operation using the smear data stored in the storage means for an image output signal read from the image sensor by application of a read gate pulse, and included in the image output signal A digital still camera, comprising: a smear correction operation circuit that removes a smear component that is generated. 2. The method according to claim 1, wherein the driving circuit control means turns off a read gate pulse and acquires the smear data when an electronic shutter value based on a photometric calculation is set to a higher speed side than a predetermined value. The digital still camera according to claim 1, wherein 3. When the electronic shutter value based on the photometric calculation is set to a higher speed than a predetermined value, a photographer is made to select whether to turn off a read gate pulse and acquire the smear data. And selecting means for inputting the instruction. The drive circuit control means determines ON / OFF of a read gate pulse in accordance with the instruction input from the selection means, and controls acquisition timing of smear data. The digital still camera according to claim 1, wherein: 4. A monitor mode which waits for an input of a photographing start signal while continuously or intermittently displaying an image acquired through said image pickup means on a display section, and periodically reads out said readout gate pulse. 2. The digital still camera according to claim 1, wherein the digital still camera is configured to be turned off to obtain the smear data. 5. An image pickup device in which photoelectric conversion elements are two-dimensionally arranged and have a vertical transfer section and a horizontal transfer section for transferring signal charges accumulated in each photoelectric conversion element, and driving for driving the image pickup element. A circuit, based on a photometric operation, discharging unnecessary charges accumulated in the photoelectric conversion element, controlling exposure time by controlling charge accumulation time by the photoelectric conversion element, and exposure control means read out from the imaging element. An A / D converter for digitizing an imaging output signal, a signal processing circuit for processing data output by the A / D converter, and image data processed by the signal processing circuit in response to an input of a shooting start signal Recording means for recording on a recording medium; and turning off a read gate pulse for reading signal charges accumulated in the photoelectric conversion element, and transferring and driving the vertical transfer unit and the horizontal transfer unit to perform vertical conversion. Drive circuit control means for controlling the drive circuit so as to output a smear component corresponding to the charge remaining in the transmission unit from the image sensor, and a light receiving area of the image sensor is divided into a plurality of photometric areas in advance, A divisional photometric calculation means for acquiring photometry information for each photometry area; and a smear data for acquiring smear correction data for each photometry area using the divisional photometry calculation means to capture smear data including a smear component of one entire screen. Correction data obtaining means, storage means for storing smear correction data obtained by the smear correction data obtaining means, and an image pickup output signal read from an image sensor by application of the read gate pulse, to the storage means Smear compensation that removes the smear component contained in the imaging output signal by performing a compensation operation in units of photometry area using the stored smear compensation data A digital still camera, comprising: a positive operation circuit;