JP4144012B2 - Mechanical shutter adjustment method for electronic camera and electronic camera - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a mechanical shutter adjustment method for an electronic camera, and more particularly to a method for correcting variations in the control time of each mechanical shutter in an electronic camera that controls exposure time by using both a mechanical shutter and an electronic shutter.
[0002]
[Prior art]
An electronic camera that uses both a so-called electronic shutter function for controlling the charge accumulation time of the image sensor and a mechanical shutter (mechanical shutter) is disclosed in, for example, Japanese Patent Laid-Open No. 9-83875.
This type of electronic camera uses only the electronic shutter function when monitoring a preview video on a liquid crystal monitor or the like provided on the main body before shooting, or when calculating exposure (AE) immediately before shooting. The mechanical shutter and electronic shutter are used in combination only when shooting (during actual imaging).
[0003]
[Problems to be solved by the invention]
However, such conventional electronic cameras have the following problems. That is, the mechanical shutter has a mechanical delay from when an electrical mechanical shutter driving pulse for instructing the operation of the shutter is applied to when the shutter is actually operated. This delay has a different value for each unit, and varies as a shutter. This variation is referred to as a machine difference in this specification.
[0004]
Although it is possible to suppress this machine difference within a certain range with high accuracy, the result is a very expensive shutter.
In addition, even if the above-mentioned machine difference is adjusted by a mechanical shutter alone, there is a problem that after the shutter is actually incorporated into the camera, it may vary due to mechanical stress associated with assembly. .
[0005]
The present invention has been made in view of such circumstances, and a mechanical shutter adjustment method for an electronic camera capable of adjusting the variation (mechanical difference) of the mechanical shutter with high accuracy using simple means. And electronic cameras The purpose is to provide.
[0006]
[Means for Solving the Problems]
According to a first aspect of the present invention, there is provided an electronic camera having both an electronic shutter for controlling a charge accumulation time of the image pickup device and a mechanical shutter capable of shielding / opening an incident optical path to the image pickup device. The deviation from the specified exposure control time caused by the mechanical delay between the mechanical delay until the mechanical shutter is actually closed after applying the mechanical shutter drive pulse to instruct the mechanical shutter closing operation. The Applied Do timing And charge accumulation start timing by electronic shutter Correct by adjusting A mechanical shutter adjustment method for an electronic camera, wherein the adjustment of the timing for applying the mechanical shutter driving pulse is performed so that the closing operation of the mechanical shutter is completed before the readout timing of the image sensor. The charge accumulation start timing by the shutter is adjusted by using only an electronic shutter to control the exposure time so that the predetermined accumulation time is obtained, and imaging a light source whose amount of light has been grasped in advance, and an output signal read from the image sensor at this time To obtain the first integrated data, and to use the electronic shutter and the mechanical shutter together to control the exposure time to image the light source, and at this time the output signal read from the image sensor is integrated to Obtaining the integrated data of two, and based on a comparison between the first integrated data and the second integrated data. Te, the adjustment of the charge accumulation start timing by the electronic shutter is carried out It is characterized by that.
[0007]
That is, the exposure time is defined by the start of charge accumulation by the electronic shutter and the closing operation of the mechanical shutter. In the present invention, the shutter driving is performed in consideration of the mechanical delay of different mechanical shutters. The control timing of the mechanical shutter drive pulse is adjusted on the control system side. In this way, by shifting the application timing of the mechanical shutter drive pulse back and forth by the time corresponding to the deviation of the actual control time with respect to the specified exposure time, the deviation is substantially corrected. Thereby, it is possible to easily adjust the mechanical shutter with high accuracy without using a special adjustment jig or the like.
[0008]
Also, as in the present invention, To adjust the exposure start timing (charge accumulation start timing) back and forth on the electronic shutter control side Therefore It is possible to correct the variation in the actual control time with respect to the specified exposure time. Thereby, it is possible to easily adjust the mechanical shutter with high accuracy without using a special adjustment jig or the like.
[0009]
In addition, When the mechanical shutter adjustment as described above is performed, it is expected that another variation factor is added due to mechanical stress after the mechanical shutter is actually incorporated into the camera. Therefore, the claims 5 As described above, it is desirable to adjust the mechanical shutter after the mechanical shutter is incorporated into the camera. In this respect, in the mechanical shutter adjustment method of the present invention, the mechanical difference of the mechanical shutter is adjusted by the timing of the shutter drive control, so that the mechanical difference can be easily adjusted even after being incorporated into the camera.
[0011]
In this case, the claim 6 For at least two types of accumulation time corresponding to a plurality of shutter times as described in , Electric By adjusting the charge accumulation start timing by the sub shutter, the adjustment can be made with higher accuracy. In the case of an electronic camera having a variable aperture, the center of the mechanical shutter may not match the aperture. 7 As described above, when the electronic camera has a variable aperture, at least two types of apertures are changed for each aperture by changing the F value of the aperture. , Electric It is desirable to adjust the charge accumulation start timing by the child shutter. Thereby, adjustment with higher accuracy becomes possible.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, preferred embodiments of a mechanical shutter adjusting method for an electronic camera according to the present invention will be described in detail with reference to the accompanying drawings.
FIG. 1 is a block diagram showing the configuration of an electronic camera to which the present invention is applied. The electronic camera 10 mainly includes a photographing lens 12, an aperture 14, a mechanical shutter 16, a solid-state imaging device 18, an analog signal processing circuit 20, an A / D converter 22, a main signal processing unit 24, a memory 26, and a D / A converter. 28, a liquid crystal monitor 30, a compression / decompression circuit 32, a memory card 34, a control circuit 36, a central processing unit (CPU) 38, and the like.
[0013]
Although the photographic lens 12 is shown in a simplified manner in the drawing, it is composed of one or a plurality of lenses, and may be a lens having a single focal length (fixed focal point), or may be a zoom lens or a step zoom lens. The focal length may be variable. The photographing lens 12 is controlled in focus and the like via a control circuit 36.
In the diaphragm 14, for example, a plurality of diaphragm holes having different diameters are formed in one diaphragm plate, and the diaphragm can be switched by an electric drive means (not shown). In the figure, the diaphragm 14 has a diaphragm plate having two kinds of diaphragm holes. However, when the diaphragm is fixed, when the diaphragm can be continuously changed, or with a shutter. A configuration in which the diaphragm is shared is also possible.
[0014]
The mechanical shutter 16 is formed of a light-shielding plate that can be moved forward and backward in the incident optical path of the solid-state image sensor 18, and shields / opens the incident optical path of the solid-state image sensor 18 by an electric drive unit (not shown) controlled via the control circuit 36.
A known two-dimensional imaging device (surface imaging device) is used for the solid-state imaging element 18. There are various types of imaging devices such as a CCD type, a MOS type, and a CID type, and any type of imaging device may be adopted. In this embodiment, a photoelectric conversion element (photosensor) is two-dimensional. An interline CCD image pickup device is used in which signal charges accumulated in each sensor are output via a vertical transfer path and a horizontal transfer path.
[0015]
Further, the solid-state imaging device 18 is provided with a sweep drain for discharging unnecessary charges, and by driving the readout gate by a shutter gate pulse, the signal charge accumulated by each sensor is swept to the sweep drain (CCD substrate). Can be thrown away. That is, this imaging device has a so-called electronic shutter function that controls the accumulation time (shutter speed) of charges accumulated in each sensor by the shutter gate pulse.
[0016]
The light passing through the photographing lens 12 is regulated by the diaphragm 14 and the mechanical shutter 16 and projected onto the solid-state image sensor 18. At this time, the charge accumulation time of the solid-state imaging device 18 is controlled by the electronic shutter function via the control circuit 36. The subject image formed on the light-receiving surface of the solid-state image sensor 18 is converted into signal charges in an amount corresponding to the amount of incident light by each sensor and sequentially read out as an imaging output signal, and then the analog signal processing circuit 20. To be supplied.
[0017]
The analog signal processing circuit 20 includes a CDS clamp circuit, a gain adjustment circuit, and the like, and appropriately processes an imaging output signal (analog electrical signal) input from the solid-state imaging device 18 based on control of the control circuit 36. The signal output from the analog signal processing circuit 20 is converted into a digital signal by the A / D converter 22 and then applied to the main signal processing unit 24.
[0018]
The main signal processing unit 24 includes a gain adjustment unit 40, an offset circuit 42, an AE integration circuit 44, a histogram generation unit 46, a digital signal processing circuit 48, and the like. The data output from the A / D converter 22 is added to the AE integrating circuit 44, the histogram generating unit 46, and the digital signal processing circuit 48 via the gain adjusting unit 40 and the offset circuit 42.
[0019]
The AE integrating circuit 44 integrates the imaging output signals (R, G, B digital signals) for one screen obtained from the A / D converter 22. The integrated value thus obtained corresponds to data indicating the brightness of one screen, and exposure control such as electronic shutter control is performed based on this integrated value.
The histogram generation unit 46 creates a histogram indicating the distribution of the integrated value of the image sensor signal with respect to the signal level from the data for one screen obtained from the A / D converter 22. A gain value and an offset value are determined based on the histogram calculation, and the gain and offset are controlled from the CPU 38 via the control circuit 36.
[0020]
In this way, the signal that has passed through the gain and offset control is applied to the digital signal processing circuit 48. The digital signal processing circuit 48 includes a luminance (Y) signal generation circuit and a color difference (C) signal generation circuit, and performs Y / C signal processing on the signal input from the offset circuit 42. The image data that has been subjected to Y / C signal processing by the digital signal processing circuit 48 is temporarily stored in the memory 26.
[0021]
The image data stored in the memory 26 is decoded, converted to an analog signal by a D / A converter 28, and supplied to a liquid crystal monitor 30 as image display means. In this way, the image captured by the solid-state image sensor 18 is displayed on the liquid crystal monitor 30. The liquid crystal monitor 30 displays a still image shot based on a shooting start signal generated by pressing a shutter button (not shown) or the like, and also displays a video (through video or intermittent image) before the shooting start signal is input. Is displayed. The signal converted into an analog signal by the D / A converter 28 can be taken out as an external video output such as a video output terminal.
[0022]
Also, the actual image data acquired in response to the input of the shooting start signal is guided from the memory 26 to the compression / decompression circuit 32, where it is compressed according to a predetermined format (for example, JPEG). The data is recorded on a memory card 34 as a recording medium. The form of the recording medium can be various forms such as smart media and IC card.
[0023]
The image data stored in the memory card 34 can be called via the CPU 38. The called image data is decompressed and reproduced by the compression / decompression circuit 32, and then the liquid crystal via the memory 26 and the D / A converter 28. It can be output to the monitor 30 or supplied to a video signal output terminal (not shown) or the like and output to another external device.
The CPU 38 is connected to the control circuit 36, the AE integrating circuit 44, the histogram generating unit 46, the digital signal processing circuit 48, the memory 26, the memory card 34, and the like, and various exposure values, focus positions, and the like according to a predetermined algorithm. Calculations are performed, and controls such as automatic exposure control, auto focus, auto strobe, and auto white balance are comprehensively managed. Further, the CPU 38 controls a corresponding circuit based on various input signals input from an operation unit (not shown) such as a release button or mode setting means.
[0024]
The autofocus means can take various forms. For example, the focus evaluation value indicating the sharpness of the subject image is calculated from the image signal, and the focus position is calculated based on the focus evaluation value. Then, the photographing lens 12 is controlled through a focus drive circuit (not shown) according to the calculated focus position, and the focus position is set. In addition, a known distance measuring means such as an AF sensor may be used.
[0025]
On the other hand, the AE integrated value obtained by the AE integrating circuit 44 is notified to the CPU 38, and the CPU 38 calculates an exposure control value indicating the exposure time. The obtained exposure control value is notified from the CPU 38 to the control circuit 36, and control such as automatic exposure control, auto strobe, and auto white balance is performed via the control circuit 36.
[0026]
The control circuit 36 controls the driving circuit of the solid-state imaging device 18 based on the exposure control value notified from the CPU 38, sets the charge accumulation time of the solid-state imaging device 18, that is, the electronic shutter value, and selects the aperture 14. The opening / closing timing of the mechanical shutter 16 is controlled. In this way, all exposure control of the electronic camera 10 is automatically performed.
[0027]
In the electronic camera configured as described above, at the time of AE or preview, the mechanical shutter 16 is kept open, and only the electronic shutter is used to control the charge accumulation time (that is, the exposure time) of the solid-state imaging device 18. At the time of actual shooting (when a recorded image is captured), shooting is performed using both the mechanical shutter 16 and the electronic shutter.
[0028]
FIG. 2 shows a timing chart of a shooting sequence at the time of actual imaging. In the figure, VD is a vertical drive pulse, and HD is a horizontal drive pulse. The cycle of the vertical drive pulse corresponds to the readout cycle Tv for reading a signal from the solid-state imaging device 18. On the other hand, the period of the horizontal drive pulse corresponds to the horizontal scanning period (1H).
As shown in the figure, the mechanical shutter 16 is in the open state before the start of the main imaging, and after the vertical drive pulse is input, the accumulation of electric charges is started from the time t1. After the start of charge accumulation at time t1, the shutter drive pulse goes high (H) at time t2 to instruct shutter drive. Then, after a certain mechanical delay, the mechanical shutter 16 is actually closed to shield the solid-state imaging device 18 from light.
[0029]
Therefore, the actual exposure time is the time from the start of charge accumulation by the electronic shutter (time t1) to the time when the mechanical shutter is closed (t3). The charge accumulation signal obtained by such exposure is read during a read period synchronized with the next vertical drive pulse. The mechanical shutter 16 is returned to the open state at an appropriate time after reading.
[0030]
In the main imaging using both the mechanical shutter 16 and the electronic shutter, since the end of exposure is defined by light shielding by the mechanical shutter 16, light does not enter the solid-state imaging device 18 after the end of exposure. Therefore, smear does not occur in principle in the main imaging.
On the other hand, as shown in FIG. 3, the mechanical shutter 16 remains open during the display of the preview moving image (during monitoring) or during photometry (during AE) performed prior to the main imaging, and the exposure period. Is defined only by the electronic shutter. Therefore, light continues to be incident on the solid-state imaging device 18 even after the charge accumulation time (Te) by the electronic shutter ends (after the exposure ends). That is, as shown in FIG. 4, during the readout period (Tv) synchronized with the next vertical drive pulse, light continues to strike the solid-state image sensor 18, and this is applied to the vertical transfer path (vertical transfer CCD) of the solid-state image sensor 18. Leakage and smear occur.
[0031]
As described with reference to FIG. 2, the mechanical shutter 16 has a mechanical delay until the mechanical shutter 16 actually starts moving after the electrical mechanical shutter driving pulse is applied. This delay is a unique value for each mechanical shutter, and there is a difference between individuals. Conventionally, this variation (mechanical difference) is adjusted so as to be within a predetermined range in the manufacturing process of the mechanical shutter, but there is a problem that this increases the cost.
[0032]
Therefore, in the present embodiment, on the assumption that there is a difference in mechanical shutter, the camera is adjusted as a whole after being incorporated in the camera, thereby reducing the cost.
Here, a procedure of a method for adjusting the mechanical shutter 16 in the electronic camera 10 will be described.
[0033]
First, the mechanical shutter 10 is attached to the camera, and as shown in FIG. 5, the position of the mechanical shutter driving pulse (application) is set so that the longest shutter time is obtained within the range not exceeding the vertical driving period (1 V) of the solid-state imaging device 18. Timing). The position of the mechanical shutter drive pulse is adjusted by a delay time from the vertical drive pulse (VD) with reference to the vertical drive pulse (VD). In practice, it is difficult to adjust the shutter time to the very inner side of the vertical drive cycle, so the adjustment is performed with a certain margin.
[0034]
In addition, since the mechanical shutter 16 needs to be closed for a certain period of time, an intermediate point between the time when the shutter starts to close and the time when the shutter closes is defined as a “shutter closing time”. Closed (actual closing) is called “optical closing” to distinguish the two.
In general, it is difficult to detect the operation of the mechanical shutter 16 after the mechanical shutter 16 is incorporated into the camera. In this regard, in this example, the operation of the mechanical shutter 16 is detected as follows.
[0035]
That is, obviously, the shutter drive pulse is sent from the control circuit 36 so that the optical closing time of the mechanical shutter 16 is later than the readout start timing of the image sensor, and the output of the AE integrating circuit 44 is obtained. Thereafter, the output of the AE integrating circuit 44 is obtained while gradually shifting the output timing of the shutter driving pulse forward (while shifting).
[0036]
FIG. 6 shows a state in which the output of the AE integrating circuit 44 is monitored while moving the timing of the shutter drive pulse. As shown in the figure, looking at the relationship between the amount of movement of the shutter drive pulse timing and the output (integrated value) of the AE integrating circuit 44, the optical closing time of the mechanical shutter 16 is Until the vicinity of the read timing, the output of the AE integrating circuit 44 shows a substantially constant value. Then, when the optical closing time of the mechanical shutter 16 reaches the vicinity of the readout timing of the image sensor, the output of the AE integrating circuit 44 starts to decrease, and the optical closing time of the mechanical shutter 16 becomes the readout timing of the imaging device. From the previous time point, the output (integrated value) of the AE integrating circuit 44 decreases in proportion to the amount of movement of the shutter drive pulse of the mechanical shutter 16.
[0037]
At the time of mechanical shutter adjustment, adjustment is made with a margin so that the optical closing of the mechanical shutter 16 is completed before the reading timing of the image sensor based on the change in the integrated value as shown in FIG.
Then, after the mechanical shutter 16 is adjusted, the electronic shutter is adjusted. The electronic shutter adjustment procedure will be described below.
[0038]
For example, the image sensor is driven by an electronic shutter so that the accumulation time corresponds to 1/512 seconds (the highest speed that can be controlled using the mechanical shutter 16 with this camera). The light source is imaged. Then, an integrated value (reference integrated value) of the output signal read from the image sensor is obtained. Thereafter, while changing the exposure start position (corresponding to the charge accumulation start timing) of the electronic shutter, the same light source is imaged using the mechanical shutter 16 and the electronic shutter together to obtain the signal integrated value of the image sensor.
[0039]
While changing the integrated value (hereinafter referred to as the reference integrated value) of the image pickup signal obtained by using only the electronic shutter without using the mechanical shutter 16 and the exposure start position (charge accumulation start timing) of the electronic shutter. The signal integrated value obtained by using the mechanical shutter together is compared, and the exposure start position at which the signal integrated value indicating the closest value to the reference integrated value is obtained is set as the electronic shutter reference position.
[0040]
After performing such setting, if exposure is performed for longer than 1/512 seconds, the exposure start position should be shifted forward by using the reference position of the electronic shutter as a reference. Good.
As described with reference to FIGS. 3 and 4, when the mechanical shutter 16 and the electronic shutter are used together, smear does not occur because light does not enter the solid-state imaging device 18 after the exposure is completed, but only with the electronic shutter. In the case of controlling the exposure period, light continues to enter the solid-state image sensor 18 after the charge accumulation time by the electronic shutter (after the exposure) ends, and smear occurs. Therefore, in order to adjust the electronic shutter with higher accuracy, it is desirable to use data obtained by performing smear correction to remove smear components.
[0041]
Next, an example of smear correction will be described.
When light enters the light receiving surface of the solid-state image sensor 18 through the photographing lens 12, signal charges corresponding to the intensity of the light incident on the photoelectric conversion elements of the solid-state image sensor are gradually generated. Thus, the signal charges accumulated for a certain period of time are simultaneously transferred to the vertical transfer CCD by the readout gate pulse applied from the imaging drive circuit, and are vertically transferred by the application of the vertical transfer pulse. Then, the signal charge transferred to the final stage of the vertical transfer CCD is transferred to the horizontal transfer CCD, and is taken out as a signal voltage through the output unit by applying a horizontal transfer pulse.
[0042]
Usually, the imaging drive circuit outputs a readout gate pulse synchronized with the vertical drive pulse (VD), and reads out an imaging output signal every readout cycle Tv. In this case, when the electronic shutter value (Te) is set at a higher speed than the read cycle Tv in accordance with the calculation of the exposure value, a shutter gate pulse for discharging unnecessary charges prior to the application of the read gate pulse is read out. It is applied to the gate and unnecessary charges are swept away to the CCD substrate. Thereafter, the signal charge accumulated for a predetermined charge accumulation time Te indicated by the electronic shutter value is read by the read gate pulse. In this way, the read data is integrated for all pixels to obtain light amount data for one screen.
[0043]
On the other hand, when measuring smear, the readout gate pulse output every readout cycle Tv is forcibly turned off, and the signal charge of the photoelectric conversion element is not transferred to the vertical transfer CCD (transfer path). Only the vertical transfer CCD and the horizontal transfer CCD are driven to take out an output signal from the output unit.
Thus, the imaging output signal obtained with the readout gate pulse turned off does not include the signal charge component accumulated in the photoelectric conversion element, but includes only the smear component leaked into the vertical transfer CCD. In this way, the read data is integrated for all pixels, and smear for one screen is measured.
[0044]
Thus, after the readout gate pulse is stopped and smear data is obtained, the image is taken using an electronic shutter as usual, and the accumulated value of the previous smear (data including smear) is obtained from the obtained accumulated data (data including smear). By subtracting (smear data), an integrated value from which smear components have been removed is obtained.
As described above, by adjusting the electronic shutter using the data from which the smear component has been removed, it is possible to perform adjustment with higher accuracy.
[0045]
According to the mechanical shutter adjustment method of the electronic camera according to the present embodiment, the mechanical shutter can be adjusted to be surely optically closed in the vicinity immediately before the readout timing of the image sensor, and unnecessary charges are generated in the image sensor. Accumulation time is small and the occurrence of smear (noise) can be suppressed. Further, once the shutter drive pulse application timing is determined, there is an advantage that the accumulation time of the image sensor can be controlled only by the exposure start timing of the electronic shutter.
[0046]
Subsequently, another embodiment of the present invention will be described.
Even if there is a machine difference in the mechanical delay of the mechanical shutter 16, this machine difference should be within a certain range. Therefore, as shown in FIG. 7, assuming the shortest and longest mechanical delay of the mechanical shutter that varies between individuals, the mechanical shutter mechanical delay is within the range defined by this shortest and longest. Based on this assumption, the shutter drive pulse application timing (shutter drive start position) is set to a timing at which it is estimated that the shutter is optically closed before the image sensor reading timing.
[0047]
After this setting, the electronic shutter is adjusted in the same procedure as described above. At this time, the same applies to the point of using data from which smear components have been removed. This method has the advantage that the fine adjustment process of the mechanical shutter can be omitted, and the adjustment work is simplified.
The adjustment of the electronic shutter in each of the above-described embodiments is desirably performed not only for one shutter time but also for a plurality of times for different shutter times. This is because the electronic shutter can be adjusted only for each limited time step (for example, one horizontal drive cycle unit), and an adjustment with only one point may cause an error. Therefore, if adjustment is performed at two or more points, the error can be reduced and adjustment with higher accuracy can be achieved.
[0048]
Further, when a variable aperture is used in the electronic camera 10 like the aperture 14 in FIG. 1, it is desirable to perform adjustment by changing the aperture. This is because the center of the stop does not necessarily coincide with the center of the optical axis, and depending on the system, the stop may be arranged at a position deviated from the center of the optical axis. This is because there may be a case where the shutter is not located at the center of the optical axis and a case where the shutter is not necessarily center-symmetric.
[0049]
【The invention's effect】
As described above, according to the mechanical shutter adjustment method of the electronic camera according to the present invention, the variation in the exposure control time caused by the mechanical delay of each mechanical shutter can be reduced by the mechanical shutter drive pulse. The Applied Do timing as well as Electronic shutter by Since the charge accumulation start timing is adjusted by appropriately shifting it back and forth, the mechanical shutter adjustment jig, which has been required in the past, is no longer necessary. The mechanical shutter can be adjusted accurately.
[0050]
Further, according to the present invention, it is possible to provide an electronic camera that can perform photographing with high precision AE without increasing the precision of the mechanical shutter more than necessary.
[Brief description of the drawings]
FIG. 1 is a block diagram showing a configuration of an electronic camera to which the present invention is applied.
FIG. 2 is a timing chart showing a shooting sequence during main imaging.
FIG. 3 is a timing chart showing a sequence during preview and AE.
FIG. 4 is a timing chart showing the relationship between an exposure time and a readout period when using an electronic shutter used to explain the cause of smear.
FIG. 5 is a timing chart showing how the shutter time is set so as not to exceed the vertical drive cycle
FIG. 6 is a graph showing the relationship between the mechanical shutter drive pulse application timing and the signal integrated value of the image sensor;
FIG. 7 is a timing chart used to explain another embodiment of a shutter adjustment method for an electronic camera according to the present invention.
[Explanation of symbols]
10. Electronic camera
12 ... Photography lens
14 ... Aperture
16 ... Mechanical shutter
18 ... Solid-state imaging device
20 ... Analog signal processing circuit
22 ... A / D converter
28 ... D / A converter
30 ... LCD monitor
36 ... Control circuit
38 ... Central processing unit (CPU)
44 ... Integration circuit for AE
46. Histogram generator
48. Digital signal processing circuit

Claims (8)

In an electronic camera having both an electronic shutter that controls the charge accumulation time of the image sensor and a mechanical shutter that can shield / open the incident optical path to the image sensor,
After applying the mechanical shutter drive pulse to instruct the mechanical shutter closing operation, the timing from which the mechanical shutter drive pulse is applied to the deviation from the specified exposure time caused by the mechanical delay between the mechanical delay until the mechanical shutter actually closes And a mechanical shutter adjustment method for an electronic camera that is corrected by adjusting the charge accumulation start timing by the electronic shutter ,
The adjustment of the timing of applying the mechanical shutter drive pulse is performed so that the closing operation of the mechanical shutter is completed before the readout timing of the image sensor,
Adjustment of the charge accumulation start timing by the electronic shutter is
Using only an electronic shutter, the exposure time is controlled so that a predetermined accumulation time is obtained, and a light source whose amount of light is grasped in advance is imaged. At this time, output signals read from the image sensor are integrated to obtain first integrated data. A process of acquiring;
A step of taking an image of the light source by controlling an exposure time using an electronic shutter and a mechanical shutter together, and obtaining second integrated data by integrating output signals read from the image sensor at this time;
Including
A mechanical shutter adjustment method for an electronic camera, wherein the charge accumulation start timing is adjusted by an electronic shutter based on a comparison between the first integrated data and the second integrated data . The adjustment of the charge accumulation start timing by the electronic shutter includes a step of calculating a smear component having the same charge accumulation time as the step of acquiring the first integrated data, and a step of removing the smear component from the first integrated data. Further including
The charge accumulation start timing is adjusted by an electronic shutter based on a comparison between the first integrated data from which the smear component has been removed and the second integrated data. Mechanical shutter adjustment method for electronic cameras. Adjustment of the charge accumulation start timing by the electronic shutter is as follows:
Use only an electronic shutter to control the exposure time so that a predetermined accumulation time is obtained, image a light source whose amount of light is known in advance, and instruct to start reading the signal charge accumulated in the photoelectric conversion element of the image sensor Outputting a readout signal to be acquired and integrating the output signals read out from the image sensor at this time to obtain first integration data;
The light source is imaged under the same exposure conditions as the first integrated data, the output of the readout signal is turned off, and the output signal read from the image sensor at this time is integrated and included in the first integrated data Obtaining a smear component;
Removing the smear component from the first integrated data;
A step of taking an image of the light source by controlling an exposure time using an electronic shutter and a mechanical shutter together, and obtaining second integrated data by integrating output signals read from the image sensor at this time;
Including
The charge accumulation start timing is adjusted by an electronic shutter based on a comparison between the first integrated data from which the smear component has been removed and the second integrated data. Mechanical shutter adjustment method for electronic cameras. Adjustment of the application timing of the mechanical shutter drive pulse is as follows:
Third output data is obtained by integrating the output signals read from the image sensor at each output timing while gradually shifting the output timing of the mechanical shutter drive pulse in time. Including the step of obtaining
Based on the relationship between the application timing of the mechanical shutter drive pulse and the third integrated data, the mechanical shutter drive pulse is set so that the closing operation of the mechanical shutter is completed before the readout timing of the image sensor. The mechanical shutter adjustment method for an electronic camera according to any one of claims 1 to 3, wherein the application timing is adjusted. Adjustment of the charge accumulation start timing by adjusting and electronic shutter of application timing of the mechanical shutter driving pulses to any one of claims 1 to 4, characterized in that takes place after incorporating the mechanical shutter in the camera The mechanical shutter adjustment method of the electronic camera as described . For at least two or more types of storage time corresponding to a plurality of shutter time, before Symbol electrons according to any one of claims 1 to 5, characterized in that the adjustment of the charge accumulation start timing by the electronic shutter How to adjust the mechanical shutter of the camera. If the electronic camera has a variable aperture, claim 1, characterized in that each aperture each for at least two or more types of the diaphragm by changing the F value of the diaphragm, the front SL adjustment of the charge accumulation start timing by the electronic shutter The mechanical shutter adjustment method for an electronic camera according to claim 1 . In an electronic camera having both an electronic shutter that controls the charge accumulation time of the image sensor and a mechanical shutter that can shield / open the incident optical path to the image sensor,
After applying the mechanical shutter drive pulse to instruct the mechanical shutter closing operation, the timing from which the mechanical shutter drive pulse is applied to the deviation from the specified exposure time caused by the variation between the mechanical delays until the mechanical shutter actually closes And an electronic camera that corrects by adjusting the charge accumulation start timing by the electronic shutter,
First adjusting means for performing timing for applying the mechanical shutter driving pulse so that the closing operation of the mechanical shutter is completed before the reading timing of the image sensor;
Using only an electronic shutter, the exposure time is controlled so that a predetermined accumulation time is obtained, and a light source whose amount of light is previously grasped is imaged. At this time, output signals read from the image sensor are integrated to obtain first integrated data. And acquiring the second integrated data by accumulating the output signals read from the image sensor at this time by capturing an image of the light source by using an electronic shutter and a mechanical shutter together to control the exposure time. Second adjusting means for adjusting the charge accumulation start timing by the electronic shutter based on a comparison between the one integrated data and the second integrated data;
An electronic camera characterized by comprising:

Images