JP2004053824A - Focusing device and signal accumulation device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent inconvenience in which light impinges on dark pixels of a signal accumulation sensor. <P>SOLUTION: It is judged whether an accumulation signal from a dark pixel of the sensor comprising a plurality of pixels reaches a specified level and when the specified level is reached, processing such as range finding processing using the accumulation signal is inhibited. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a signal storage device using a signal storage type sensor, or a focusing device that obtains a distance measurement or a defocus amount using the device and performs focusing.
[0002]
[Prior art]
Conventionally, various proposals have been made for a charge storage type photoelectric conversion device, and proposals have been made for a distance measuring device to which the photoelectric conversion device is applied.
[0003]
In the distance measuring device as described above, the photoelectric conversion device generally includes a plurality of photoelectric conversion elements arranged at a predetermined pixel pitch, a charge storage unit corresponding to each photoelectric conversion element, a circuit for controlling charge storage, and a photoelectric conversion device. A circuit for reading an output is formed on one semiconductor chip.
[0004]
FIG. 2 is a schematic diagram of the distance measuring device as described above.
[0005]
In FIG. 2, reference numeral 201 denotes a first light receiving lens forming a first optical path, and reference numeral 202 denotes a second light receiving lens forming a second optical path.
[0006]
Reference numeral 200 denotes a photoelectric conversion device, which includes a sensor array, a signal storage unit, a peak detection unit, and a signal output unit described below.
[0007]
Reference numeral 203 denotes a first sensor array in which a plurality of photoelectric conversion elements are linearly arranged, 204 denotes a second sensor array, and 205 denotes a first signal storage unit. The converted charge is converted into a voltage and stored for each pixel. Further, the signal stored in the signal storage unit 205 can be cleared by the RES pulse. Reference numeral 206 denotes a second signal storage unit, which converts charges photoelectrically converted by the second sensor array 202 into a voltage and stores the charge for each pixel, similarly to the first storage unit.
[0008]
Further, the sensor array has pixels shielded by aluminum (hereinafter, dark pixels). The dark pixels also perform an accumulation operation, and are used for a PKMON signal and a reference signal of a signal level of each pixel described later.
[0009]
A peak detection unit 207 detects the MAX value of the signal accumulation level of each pixel of the first signal accumulation unit 205 and the second signal accumulation unit 206, and outputs a difference from a dark pixel signal as a PKMON signal. A first signal output unit 210 sequentially outputs a signal corresponding to each pixel of the first signal storage unit as an OUT signal by a CLK1 pulse. Reference numeral 211 denotes a second signal output unit, which outputs a signal corresponding to each pixel of the second signal storage unit sequentially as an OUT signal by a CLK2 pulse, similarly to the first signal output unit 210.
[0010]
An accumulation operation and a signal read operation of the distance measuring apparatus of FIG. 2 will be described with reference to a timing chart of FIG.
[0011]
First, the signals in the first signal storage unit 205 and the second signal storage unit 206 are cleared by the RES pulse L → H. At this time, the voltage levels of the dark pixel and other pixel signals are clamped to the reset voltage Vres. After a predetermined time, the RES pulse is changed from H to L and the ST pulse is changed from H to L, and signal accumulation is permitted to start the accumulation operation.
[0012]
FIG. 6 shows a luminance distribution on the sensor arrays 203 and 204. It is assumed that the signal becomes higher as the intensity of the received luminance becomes higher. The sensor array 203 includes L1 to L10, and the sensor array 204 includes R1 to R10 photoelectric conversion elements. FIG. 7A shows an image signal on the sensor array 203, and FIG. 7B shows an image signal on the sensor array 204. In FIG. 3A, a light-receiving image is formed over L3 to L7, and in FIG. 3B, a light-receiving image is formed over R4 to R8.
[0013]
During the accumulation operation, the voltage level of the signal accumulation unit decreases at an inclination corresponding to the amount of incident light for each pixel of the sensor array, and the signal level of the pixels (L5, R6) with the highest luminance (hereinafter, peak level) Vpk is the lowest output among the signal accumulation levels corresponding to each pixel. On the other hand, the level Vdk (hereinafter, dark level) of the signal of the dark pixel is hardly dropped from around Vres even when the accumulation operation is started since the signal is shielded. The peak detector 207 detects the peak level Vpk and the dark level Vdr, and outputs a difference voltage between them as a PKMON signal.
[0014]
The PKMON signal level rises at substantially the same rate as the voltage drop of the peak level Vpk, is A / D converted by an A / D conversion converter built in a control unit (not shown), and the level is checked by the control unit. .
[0015]
Then, when the PKMON signal level exceeds the accumulation stop level Vcomp, the ST pulse is changed from L to H to terminate the accumulation operation in the first signal accumulation unit 205 and the second signal accumulation unit 206. At the same time, the storage signal level of each pixel is held.
[0016]
After the end of the accumulation operation, the accumulation signal is read. Here, when a CLK1 pulse is first input as a read clock, a signal of each pixel of the first sensor array 203 is sequentially output to OUT. When the output of all the pixel signals of the first sensor array 203 is completed, the signal of each pixel of the second sensor array 204 is sequentially output to OUT by inputting the CLK2 pulse.
[0017]
At this time, the OUT signal is based on the dark level, and similarly to the PKMON signal, the output of each pixel is output as a difference signal from the dark level.
[0018]
The control unit (not shown) converts the output signal into a digital signal in synchronization with the CLK pulse and stores the converted signal in a memory in the internal control unit. When reading of the stored signals for all pixels is completed, the reading is performed. End the operation.
[0019]
As described above, based on the relative value of the image signal of the object to be measured obtained on the first sensor array 203 and the image signal of the object obtained on the second sensor array 204, the principle of triangulation is used. Find the distance to the subject.
[0020]
In the above description, the reason why the PKMON signal and the output signal of each pixel are based on the dark level is that the dark current generated during the accumulation operation is canceled by subtracting the dark level from each signal.
[0021]
[Problems to be solved by the invention]
Normally, the photoelectric conversion device is formed on a semiconductor chip, and the chip surface is shielded from light by a light-shielding material such as aluminum so that light does not enter the part other than the sensor array. I will not. However, since the side of the chip is not shielded from light, if the brightness of the subject or its surroundings is extremely high, the light incident from the side of the photoelectric conversion device causes the generated charges to leak into the sensor array or signal storage unit. In addition, unnecessary charges are accumulated.
[0022]
An image signal in a case where unnecessary charges are accumulated when light enters from the side surface of the photoelectric conversion device will be described with reference to FIGS.
[0023]
In FIG. 8, the start of the accumulation operation is started by the same operation as in FIG. Normally, the signal level of the pixel (L4, R5) having the highest luminance becomes the peak level Vpk. However, the pixel signal of the pixel having a large charge leakage, that is, the pixel signal of L1 and R10 is the peak level Vpk. Is output as Therefore, the accumulation is stopped by the pixel signal into which the electric charge has leaked. In this case, the image signals due to the leaked charges are added, and the correct image signal of the subject cannot be detected. Further, the voltage level of the dark level is also reduced due to the leakage of the electric charge to the dark pixel.
[0024]
When distance measurement is calculated based on such an image signal, erroneous distance measurement is performed.
[0025]
Next, FIG. 9 illustrates an image signal in a state in which charge leakage is larger than that in the case of FIG.
[0026]
If the leakage of the electric charge is further increased, the leakage amount to the dark pixel is also increased. Therefore, since the drop of the dark level Vdk increases, the rate of increase of the PKMON signal, which is the difference signal between the peak level and the dark level, becomes smaller than the rate of decrease of the peak level Vpk. Further, when both the peak level and the dark level reach the saturation level (0 V), the PKMON signal becomes the minimum level of 0 V.
[0027]
Normally, if the PKMON signal is small even after a predetermined time and does not exceed the accumulation stop level, it is determined that the subject brightness is low and no signal can be obtained, and the accumulation operation is stopped. In the state of FIG. 9, the pixel signals of all the sensor arrays including the dark pixels have reached the saturation level, the output signal based on the dark level becomes 0 V, and no image signal is obtained. When the amount of charge leakage is large as described above, the luminance information of the subject cannot be obtained, and even though the luminance of the subject is high, no image signal can be obtained as in the case where the detection result is dark. .
[0028]
In order to reduce the influence of charge leakage due to incident light from the side of the chip, there is a method in which the distance from the signal storage section to the chip end is sufficiently separated, but the chip area becomes large and the cost increases. The problem of becoming expensive arises.
[0029]
Further, in a distance measuring device using a light receiving means including a plurality of photoelectric conversion elements disclosed in Japanese Patent Application Laid-Open No. 09-229873, charge gradually leaks to a transfer stage CCD (such as a ring CCD) due to dark current or external light components. A method of correcting the distortion of the image signal due to the intrusion of electric charges has been proposed. Can not.
[0030]
[Means for Solving the Problems]
The invention according to claim 1 has a charge accumulation type sensor unit composed of a plurality of pixels, performs signal accumulation with respect to light from a subject received by the sensor unit, and sets a subject distance based on the accumulated signal. Or, in a focusing device that obtains a defocus amount and performs focusing,
Luminance information is obtained based on the accumulation signal in the sensor unit, and the difference between the luminance information and the luminance information from a photometric unit provided separately from the sensor unit is separated by a predetermined value or more. The inconvenience caused when unnecessary light is received by the sensor is eliminated by prohibiting the focusing operation based on.
[0031]
According to a second aspect of the present invention, a signal is accumulated for light from a subject received by a charge accumulation type sensor unit composed of a plurality of pixels without projecting a light projecting unit. Calculating the object distance or the defocus amount based on the distance and performing the focusing, and determining the object distance or the defocus amount based on the accumulated signal without projecting the light projecting means is inappropriate. Focusing is performed by causing the sensor unit to accumulate a signal with respect to light from the subject in a state where the light projecting means is projected, obtaining a subject distance or a defocus amount based on the accumulated signal, and performing focusing. In the device,
In a state where the light emitting unit is not emitting light, luminance information is obtained based on an accumulation signal accumulated in the sensor unit, and the luminance information and luminance information from a light measuring unit provided separately from the sensor unit. By prohibiting the signal accumulation operation in the state of projecting the light projecting means when the difference from the predetermined value is more than a predetermined value, when unnecessary light is received by the sensor, the auxiliary light is wasted. This prevents the distance measurement operation from being performed by projecting light.
[0032]
According to a third aspect of the present invention, in the signal storage device having a charge storage type sensor unit including a plurality of pixels including pixels in a light-shielded state, and performing signal storage in the sensor unit, the charge is stored in the light-shielded pixels. The determination unit determines whether the signal level obtained exceeds a predetermined level deviated from the first level before the start of accumulation, and detects the light receiving state of the sensor unit, so that the sensor An object of the present invention is to provide a signal storage device that detects whether unnecessary light is received.
[0033]
According to a fourth aspect of the present invention, in the device according to the third aspect, when the determining means determines that the state exceeds the predetermined level, the processing operation using a warning or an accumulation signal is prohibited. A signal storage device is provided.
[0034]
According to a fifth aspect of the present invention, there is provided a charge storage type sensor unit including a plurality of pixels including pixels in a light-shielded state, wherein signal storage is performed for light from a subject received by the sensor unit, In a focusing apparatus that performs distance measurement or defocus detection based on the detected signal and performs focusing, a signal level accumulated in the light-shielded pixel deviates from a first level before the accumulation starts. Is determined by the determination means to determine whether the state exceeds the predetermined level, and when it is determined that the state exceeds the predetermined level, focusing based on the signal accumulated by the sensor unit is prohibited. This prevents inappropriate focusing.
[0035]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, a first embodiment of the present invention will be described with reference to the drawings.
[0036]
FIG. 1 is a block diagram showing a configuration of a camera having a distance measuring device according to the present invention.
[0037]
In FIG.
Reference numeral 101 denotes a camera control unit (hereinafter referred to as a CPU), which performs overall camera sequence control, and includes an A / D conversion unit 105 and a memory 106 described later, a distance calculation unit 107, a brightness calculation unit 108, and a brightness comparison unit 109.
[0038]
Reference numeral 102 denotes a photometric unit that detects the luminance of the subject.
[0039]
Reference numeral 103 denotes a distance measuring device which has the same configuration as that of FIG. 2 and detects and outputs an image signal from a subject by two sensor arrays 203 and 204.
[0040]
An A / D converter 105 digitizes an analog signal or the like corresponding to an image signal of a subject output from the distance measuring unit 103.
[0041]
Reference numeral 106 denotes a memory for storing information such as an image signal of a subject digitized by the A / D conversion unit 105.
[0042]
Reference numeral 107 denotes a distance calculation unit that calculates the distance to the subject by calculating the phase difference between the image signals of the subject detected by the two sensor arrays 203 and 204 in FIG.
[0043]
Reference numeral 108 denotes a brightness calculating unit that calculates the brightness of the subject from the image signal of the subject detected by the distance measuring unit 103.
[0044]
Reference numeral 109 denotes a brightness comparison unit that compares the brightness of the subject detected by the photometry unit 102 with the brightness of the subject calculated by the brightness calculation unit 108 based on the output information of the distance measurement unit 103.
[0045]
Here, if the difference between the luminance of the subject detected by the photometric unit 102 and the luminance of the subject calculated by the luminance calculating unit 108 is small, the distance measuring unit 103 determines that the leakage of the charge due to the external light has not occurred. On the other hand, when the luminance difference is large, it is determined that the charge leaks due to external light. If the charge leaks due to external light, the brightness distribution of the subject detected by the distance measuring means 103 is correct by the brightness calculating means 108 due to the leaked signal and the dark pixel level as shown in FIGS. Brightness cannot be calculated. Therefore, the luminance of the subject can be different from the luminance of the subject detected by the photometric unit 102 that can correctly detect the luminance of the subject. From this difference, it is possible to detect the leakage of electric charge due to external light in the distance measuring unit 104.
[0046]
The photometric unit 102 is a photoelectric conversion element such as an SPD, and is larger than the photoelectric conversion element of the distance measuring unit 103, and can obtain many signals from a subject.
[0047]
Reference numeral 110 denotes a warning display for displaying to the photographer that distance measurement is impossible when the luminance difference is detected by the luminance comparing means 109 and light leakage is determined by the distance measuring means 102. Means.
[0048]
Reference numeral 111 denotes a shutter driving unit that performs shutter aperture control based on a detection result from the photometric unit 102;
Reference numeral 112 denotes a lens driving unit that drives a photographic lens (not shown) based on the detection result of the distance to the subject calculated by the distance calculation unit 107 and focuses the subject on the film surface.
[0049]
Reference numeral 113 denotes a film supply unit that performs automatic loading, winding, and rewinding of the film.
[0050]
Reference numeral 114 denotes a switch SW1 for activating an electric circuit in the camera by a first stroke of a shutter button (not shown) to detect photometry, distance measurement, and the like.
Reference numeral 115 denotes a second stroke of a shutter button (not shown), which is a switch SW2 serving as a start signal of a shooting sequence after the switch SW1.
[0051]
Next, the flow of the operation of the camera according to the present embodiment will be described with reference to the flowchart in FIG.
[0052]
[# 301]
First, in step 301, the CPU 101 detects whether SW1 (114), which is the first stroke of the release SW, has been turned on, and waits until SW1 is turned on. When ON of SW1 is detected, the process proceeds to the next step 302.
[0053]
[# 302]
In step 302, photometry relating to the subject is performed by the photometric unit 102, and the photometric result (subject brightness) is stored in the memory 106.
[0054]
[# 303]
Next, in step 303, signal accumulation of all pixels of the first and second sensor arrays 203 and 204 in the photometric means 103 is permitted by the RES pulse and the ST pulse, and the accumulation operation is started.
[0055]
[# 304]
In step 304, the PKMON signal level output from the peak detection unit 207 in the distance measuring unit 103 is A / D converted by the A / D conversion unit 105 built in the CPU 101, and the level is checked to store the signal. It is determined whether the amount is at a predetermined level. In this embodiment, the PKMON level increases as the accumulation amount increases. Therefore, when the PKMON level exceeds a predetermined level, it is determined that the accumulation amount has reached the predetermined level, and the process proceeds to the next step 306. Stop the accumulation operation.
[0056]
On the other hand, if the PKMON level is equal to or higher than the predetermined level, that is, if the accumulation level has not reached the predetermined level, it is determined that the accumulation level has not reached the predetermined level, and the routine proceeds to step 305.
[0057]
[# 305]
In step 305, it is determined whether or not the time from the start of accumulation (hereinafter, accumulation time) has reached a preset maximum time. If the accumulation time has not reached the maximum time, the process proceeds to step 304 to continue the accumulation. On the other hand, if the accumulation time has reached the maximum time, the process proceeds to step 306, and the accumulation operation is stopped.
[0058]
Here, the reason for judging whether or not the maximum time has been reached is, for example, in shooting in a dark place or the like, since the subject brightness is extremely low, the accumulation level does not reach the predetermined level no matter how much time passes. Therefore, setting the maximum accumulation time is to prevent the distance measurement accumulation operation from becoming uselessly long.
[0059]
[# 306]
In step 306, the accumulation operation in the first signal accumulation unit 205 and the second signal accumulation unit 206 in the distance measuring unit 103 is terminated by the ST pulse, and the accumulation signal level of each pixel is held at the same time.
[0060]
[# 307]
In step 307, a signal read operation is started.
[0061]
First, the signals of the first sensor array 203 and the second sensor array 204 in the distance measuring means 103 are sequentially output to OUT by the read clock CLK1 and CLK2 pulses.
[0062]
At this time, the A / D converter 105 performs A / D conversion in synchronization with the CLK1 pulse and the CLK2 pulse by the CPU 101 and sequentially stores the A / D conversion at a predetermined address of the memory 106.
[0063]
[# 308]
In step 308, the brightness of the subject is calculated by the brightness calculation means 108 from the image signal from the distance measurement means 103 stored in the memory 106 and the time required for accumulation. As a method of calculating the luminance, for example, a method of calculating a value corresponding to the luminance from the level of the signal indicating the peak and the accumulation time as a signal among the signals from the read sensor array, or by changing to the peak, A method of calculating a value corresponding to luminance using an average value of signals of pixels (excluding dark pixels) or a signal level from a pixel at a predetermined position or range such as a central portion is used. Further, the luminance may be obtained only from the pixel signal without using the accumulation time.
[0064]
[# 309]
In step 309, the luminance comparing unit 109 determines whether or not the difference between the subject luminance by the photometric unit 102 (step 302) and the subject luminance calculated by the distance measuring unit 103 in step 308 is equal to or less than a predetermined level. .
[0065]
If the luminance difference is equal to or less than the predetermined level, the distance measuring means 103 determines that no leakage of electric charge due to external light has occurred, and proceeds to step 310.
On the other hand, when the luminance difference is equal to or more than the predetermined level, it is determined that the leakage of the electric charge to the pixel of the distance measuring unit 103 due to the strong external light is performed, and the process proceeds to step 311.
[0066]
[# 310]
In step 310, the distance calculating means 107 calculates the distance to the subject from the phase difference between the respective image signals obtained by the sensor arrays 203 and 204 of the distance measuring means 103 stored in the memory 106, and calculates the distance. The result is stored in the memory 106.
[0067]
[# 311]
In step 311, it is determined that the difference between the subject luminance by the photometric unit 102 (step 302) and the subject luminance data calculated by the distance measuring unit 103 in step 307 is equal to or greater than a predetermined level. (Step 309) In this case, charge leaks into the pixels of the distance measuring means 103 due to strong external light, and the distance to the subject cannot be detected correctly. Therefore, the result of the distance calculation unit 107 is determined as the hyperfocal distance of the photographing lens regardless of the detection result of the distance measurement unit 103, and stored in the memory 106.
[0068]
[# 312]
In step 312, the warning display unit 110 notifies the photographer (not shown) that the distance measuring operation by the distance measuring unit 103 is impossible.
[# 313]
In step 313, it is determined whether or not SW2 is ON. When it is determined that SW2 is not ON, the process returns to step 313, and when it is determined that SW2 is ON, the process proceeds to step 314.
[0069]
[# 314]
In step 321, the drive of the photographing lens is controlled by the lens driving unit 112 according to the distance measurement result (step 310 and step 311) stored in the memory.
[0070]
[# 315]
In step 315, shutter drive control is performed by the shutter control unit 111 according to the photometric result (step 302) stored in the memory.
[0071]
[# 316]
In step 316, the film feeding means 113 controls the film feeding for the next photographic frame. This ends a series of camera sequences.
[0072]
As described above, erroneous distance measurement can be prevented by determining the leakage of the electric charge by the distance measurement means 103 based on the difference between the subject luminances obtained by the photometry means 102 and the distance measurement means 103.
[0073]
(Second embodiment)
A second embodiment according to the present invention will be described with reference to FIG.
[0074]
FIG. 7 is a block diagram showing a configuration of a camera according to the present embodiment. Since the same reference numerals as those in FIG. 1 have already been described, the description here is omitted.
[0075]
In FIG.
Reference numeral 104 denotes an auxiliary light illuminating unit that emits illumination light to the subject when the amount of accumulation of a signal from the subject in the distance measuring unit 103 is equal to or less than a predetermined level.
[0076]
Next, the flow of the operation of the camera according to the present embodiment will be described with reference to the flowchart in FIG.
[0077]
[# 501]
First, in step 501, the CPU 101 detects whether SW1 (114), which is the first stroke of the release SW, has been turned ON, and waits until SW1 is turned ON. When ON of SW1 is detected, the process proceeds to the next step 502.
[0078]
[# 502]
In step 502, photometry relating to the subject is performed by the photometric unit 102, and the photometric result (subject brightness) is stored in the memory 106.
[0079]
[# 503]
Next, in step 503, signal accumulation of all pixels of the first and second sensor arrays 203 and 204 in the photometric unit 103 is permitted by the RES pulse and the ST pulse, and the accumulation operation is started.
[0080]
[# 504]
In step 504, the PKMON signal level output from the peak detection unit 207 in the distance measuring unit 103 is A / D converted by the A / D conversion unit 105 built in the CPU 101, and the level is checked to store the signal. It is determined whether the amount is at a predetermined level. In this embodiment, the PKMON level increases as the accumulation amount increases. Therefore, when the PKMON level falls below the predetermined level, it is determined that the accumulation amount has reached the predetermined level, and the process proceeds to the next step 506. Stop the accumulation operation.
[0081]
On the other hand, if the PKMON level is equal to or higher than the predetermined level, if the accumulation level has not reached the predetermined level, it is determined that the accumulation level has not reached the predetermined level.
[0082]
[# 505]
In step 505, it is determined whether or not the time from the start of accumulation (hereinafter, accumulation time) has reached a preset maximum time. If the accumulation time has not reached the maximum time, the process proceeds to step 504 to continue accumulation. On the other hand, if the accumulation time has reached the maximum time, the process proceeds to step 506, and the accumulation operation is stopped.
[0083]
[# 506]
In step 506, the accumulation operation in the first signal accumulation unit 205 and the second signal accumulation unit 206 in the distance measuring unit 103 is terminated by the ST pulse, and the accumulation signal level of each pixel is held at the same time.
[0084]
[# 507]
In step 507, a signal read operation is started.
[0085]
First, the signals of the first sensor array 203 and the second sensor array 204 in the distance measuring means 103 are sequentially output to OUT by the read clock CLK1 and CLK2 pulses.
[0086]
At this time, the A / D converter 105 performs A / D conversion in synchronization with the CLK1 pulse and the CLK2 pulse by the CPU 101 and sequentially stores the A / D conversion at a predetermined address of the memory 106.
[0087]
[# 508]
In step 508, the level of the PKMON signal after stopping the accumulation is checked by the same operation as in step 504 to determine whether or not the accumulation amount in the distance measuring means 103 is equal to or higher than a predetermined level. If the PKMON level is equal to or more than the predetermined amount, the accumulation amount has reached the predetermined level, and the process proceeds to step 518 to calculate the distance to the subject.
[0088]
On the other hand, if the PKMON level is equal to or less than the predetermined amount, since the accumulated amount has not reached the predetermined level, it is determined that the distance measuring operation using the auxiliary light illuminating means 104 is necessary, and the process proceeds to step 509.
[0089]
[# 509]
In step 509, as in step 308 of the first embodiment, the luminance calculating unit 108 calculates the luminance of the subject from the image signal of the distance measuring unit 103 stored in the memory 106 and the time required for accumulation. Is calculated.
[0090]
[# 510]
In step 510, the luminance comparing unit 109 determines whether the difference between the subject luminance by the photometric unit 102 (step 502) and the subject luminance calculated by the distance measuring unit 103 in step 509 is equal to or less than a predetermined level. .
[0091]
If the luminance difference is equal to or less than the predetermined level, the distance measuring unit 103 determines that no leakage of electric charge due to external light has occurred, and proceeds to step 511.
[0092]
On the other hand, if the luminance difference is equal to or greater than the predetermined level, it is determined that electric charge has leaked into the dark pixels of the distance measuring means 103 due to strong external light, and the flow proceeds to step 519.
[0093]
[# 511]
In step 511, the auxiliary light illuminating means 104 is turned on, and the object is illuminated by the distance measuring means 103 so that a signal from the object can be obtained.
[0094]
[# 512]
In step 512, the accumulation operation by the distance measuring means 103 is started by the same operation as step 503.
[0095]
[# 513]
In step 513, as in step 504, the PKMON level is compared with a predetermined level to determine whether the accumulated amount has reached an appropriate level. If the PKMON level is equal to or lower than the predetermined level, the flow shifts to step 515 to stop the accumulation operation. On the other hand, if the PKMON level is equal to or higher than the predetermined level, the process proceeds to step 514.
[0096]
[# 514]
In step 514, similarly to step 505, it is determined whether the accumulation time has reached a preset maximum time. If the accumulation time has not reached the maximum time, the process proceeds to step 513, where the accumulation is continued. On the other hand, if the accumulation time has reached the maximum time, the process proceeds to step 515, and the accumulation operation is stopped.
[0097]
Here, the maximum time of the accumulation operation using the auxiliary light is set longer than the maximum time of the accumulation operation without using the auxiliary light (step 505), so that more signals from the subject can be obtained.
[0098]
[# 515]
In step 515, the accumulation operation in the first signal accumulation unit 205 and the second signal accumulation unit 206 in the distance measuring unit 103 is stopped by the same operation as in step 506.
[0099]
[# 516]
At step 516, the auxiliary light illuminating means 104 is turned off, and the routine goes to step 517.
[0100]
[# 517]
In step 517, by the same operation as step 507, the signals of the first sensor array 203 and the second sensor array 204 in the distance measuring means 103 are sequentially output to OUT, and the A / D converter 105 performs A / D conversion. The data is converted and sequentially stored at a predetermined address in the memory 106.
[0101]
[# 518]
In step 518, the distance to the subject is calculated from the phase difference between the image signals of the respective subjects obtained by the sensor arrays 203 and 204 of the distance measuring means 103 stored in the memory 106 by the distance calculating means 107.
[0102]
[# 519]
In step 519, it is determined that the difference between the subject luminance by the photometric unit 102 (step 102) and the subject luminance by the distance measuring unit 103 calculated in step 307 is equal to or higher than a predetermined level. (Step 510) In this case, charge leaks into the dark pixels of the distance measuring means 103 due to strong external light, and the distance to the subject cannot be detected correctly. Therefore, the result of the distance calculation unit 107 is determined as the hyperfocal distance of the photographing lens regardless of the detection result of the distance measurement unit 103, and stored in the memory 106.
[0103]
[# 520]
In step 520, the warning display unit 110 notifies the photographer (not shown) that the distance measurement operation by the distance measurement unit 103 is impossible.
[0104]
[# 521]
In step 521, it is determined whether or not SW2 is ON. When it is determined that SW2 is not ON, the process returns to step 521, and when it is determined that SW2 is ON, the process proceeds to step 522.
[0105]
[# 522]
In step 522, the lens driving unit 111 performs drive control of the photographing lens according to the distance measurement result (step 518 or step 519) stored in the memory 106.
[0106]
[# 523]
In step 523, shutter drive control by the shutter control means 110 is performed according to the photometric result (step 502) stored in the memory 106.
[0107]
[# 524]
In step 524, the film feeding means 112 controls the film feeding for the next photographic frame. This ends a series of camera sequences.
[0108]
When an image signal cannot be obtained due to leakage of electric charges as shown in FIG. 9 (FIG. 9), a distance measurement operation using auxiliary light is usually performed. However, as described above, when the leakage of the electric charge in the distance measuring means 103 is detected from the difference between the subject luminances obtained by the light measuring means 102 and the distance measuring means 103, the distance measuring operation by the auxiliary light is prohibited. . That is, it is possible to reduce the time required for the distance measurement operation by the auxiliary light at the time of high luminance which is not originally required.
[0109]
The method of determining the accumulation of unnecessary charges due to external light in each of the above embodiments is a method using the photometric luminance and the sensor luminance. As another method, among the pixel signals read out from the sensor in steps 307 and 507, It is determined whether the signal of the dark pixel is at a predetermined level (whether or not the level originally changes when external light does not enter and is at a predetermined level), and the level of the dark pixel is at a predetermined level. At this time, it may be determined that unnecessary charges are accumulated, and the process may proceed to steps 311 and 519.
[0110]
Further, although a distance measuring device is shown in the embodiment, the present invention may be applied to a focus detecting device that obtains a defocus amount based on a signal from a sensor.
[0111]
【The invention's effect】
As described above, in each of the embodiments, since the leakage of the charge can be determined and detected, it is possible to prevent a process (for example, a distance measuring operation) using an inappropriate signal accumulation result.
[Brief description of the drawings]
FIG. 1 is a block diagram showing a configuration of a first exemplary embodiment of the present invention.
FIG. 2 is a block diagram illustrating a configuration of a distance measuring device using a photoelectric conversion device.
FIG. 3 is a flowchart for explaining a distance measuring operation in the distance measuring apparatus according to the first embodiment of the present invention.
4 is a timing chart and an output waveform when an output signal is taken in the photoelectric conversion device of FIG. 2;
FIG. 5 is a flowchart for explaining a distance measuring operation in the distance measuring apparatus according to the second embodiment of the present invention.
6 is a diagram showing a luminance distribution on a sensor array in the photoelectric conversion device of FIG.
FIG. 7 is a block diagram illustrating a configuration of a second exemplary embodiment of the present invention.
FIG. 8 is a timing chart and an output waveform at the time of capturing when charge leakage occurs in the photoelectric conversion device of FIG. 2;
FIG. 9 is a timing chart and an output waveform at the time of capturing in a case where charge leakage further occurs in the photoelectric conversion device of FIG. 2;
[Explanation of symbols]
101 Camera control unit (CPU)
102 Photometry
103 Distance measuring means
105 A / D converter
106 memory
107 Distance calculation means
108 brightness calculation means
109 brightness comparison means

Claims (5)

It has a charge accumulation type sensor unit composed of a plurality of pixels, performs signal accumulation for light from the subject received by the sensor unit, and determines a subject distance or a defocus amount based on the accumulated signal, In a focusing device that performs focusing,
Luminance information is obtained based on the accumulation signal in the sensor unit, and the difference between the luminance information and the luminance information from a photometric unit provided separately from the sensor unit is separated by a predetermined value or more. A focusing device for inhibiting a focusing operation based on the image. Without projecting the light projecting means, the signal accumulation for the light from the subject received by the charge accumulation type sensor unit composed of a plurality of pixels is performed, and the subject distance or defocusing is performed based on the accumulated signal. In the case where it is inappropriate to obtain the amount and perform focusing, and to determine the subject distance or the defocus amount based on the accumulated signal without projecting the light projecting means, the light projecting means is projected. In a focusing device, the sensor unit performs signal accumulation for light from the subject in the state, obtains a subject distance or a defocus amount based on the accumulated signal, and performs focusing.
In a state where the light emitting unit is not emitting light, luminance information is obtained based on an accumulation signal accumulated in the sensor unit, and the luminance information and luminance information from a light measuring unit provided separately from the sensor unit. A signal accumulation operation in a state where the light emitting means is projected when the difference between the light emitting means and the light emitting means is larger than a predetermined value. In a signal storage device having a charge storage type sensor unit including a plurality of pixels including a light-shielded pixel and performing signal storage in the sensor unit, the signal level stored in the light-shielded pixel starts storing. A signal accumulating device, wherein a judging means judges whether or not a state exceeds a predetermined level deviated from a previous first level, and detects a light receiving state of the sensor section. 4. The signal storage device according to claim 3, wherein when the determination unit determines that the state exceeds the predetermined level, a processing operation using a warning or a storage signal is prohibited. It has a charge accumulation type sensor unit composed of a plurality of pixels including pixels in a light-shielded state. The sensor unit accumulates a signal with respect to light from a subject received by the sensor unit, and performs measurement based on the accumulated signal. In a focusing device that performs distance or defocus detection and performs focusing, the signal level accumulated in the light-shielded pixel exceeds a predetermined level deviated from the first level before the start of accumulation. A focus determining unit that determines whether or not the focus is on the basis of a signal accumulated by the sensor unit when it is determined that the state exceeds the predetermined level. apparatus.

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