JP2002281385A - Imaging system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent drop in image quality due to defect compensation based on defect information erroneously detected due to influence of inverse incident light, etc. SOLUTION: When defect detection is performed by a defect data detecting part 112c, judgment of reliability of the detection is first performed prior to the defect detection. Namely, a defect detection reliability judging part 112e calculates the average value of outputs (dark electric charge level) of 64×64 pixels at a center part of an image pickup area. When the average value exceeds 5 (5/255 = approximately 2%), the reliability of the detection is judged to be low. In this case, the detection is stopped. Thus, prevention of the drop of the image quality due to the defect compensation based on the erroneously detected defect information is enabled.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an imaging device, and more particularly, to an imaging device having a pixel defect detecting function.

[0002]

2. Description of the Related Art Imaging devices such as video cameras have been widely used. In recent years, electronic still cameras that mainly capture and record still images have also come into widespread use especially as digital cameras, and video movies mainly for recording moving images also have a still image capturing and recording function. Long-time exposure, which is mainly used for shooting still images, increases the exposure time by increasing the charge accumulation time in the image sensor, thereby enabling shooting without using auxiliary lighting such as a strobe even under low illumination. It is known as a technology.

On the other hand, an image pickup device such as a CCD has a dark output due to the presence of a so-called dark current, which is superimposed on an image signal, thereby deteriorating the image quality. If there is a pixel with a large dark output level, it is called a pixel defect,
It is widely practiced to supplement information using output information of neighboring pixels without using output information of the pixel. In the present specification, such a complementing process is referred to as pixel defect compensation. A predetermined (often 1/60 in NTSC) which is often determined on the premise of driving a moving image at the used frame rate
The dark output is evaluated with a standard exposure time of seconds or a predetermined margin based on the predetermined margin (for example, 1/15 second when the margin is 4 times), and a pixel having a large level is regarded as a defective pixel. The pixel defect compensation is applied.

Further, Japanese Patent Application Laid-Open No. 06-038113 discloses a technique for improving that a pixel defect involves temperature dependence and aging, so that it is not sufficient to evaluate a defective pixel just before shipment from a factory. It is known. That is, in this publication, the light receiving surface is shielded from light by closing the iris immediately after the power is turned on, and the dark output of the image sensor is evaluated prior to use of the camera. A technique for detecting defects as pixels and performing defect compensation is described.

[0005]

However, even when the technique of acquiring defective pixel information by using the output of the image sensor under light-shielding by closing the iris is used, even if the technique of acquiring defective pixel information is used.
In digital cameras with an eye-reflection optical finder, CC is affected by the back-incident light from the optical finder.
In some cases, extra light was input to D and erroneous detection was performed. This is because, for example, the vicinity of the center of the CCD is irradiated with spot-shaped light having an unclear contour, and the level of the entire area is significantly increased, so that all the pixels in the area are apparently detected as defects. Happens in. In such a case, when the defect compensation is performed on the basis of the defect address information, the image quality is more deteriorated when the defect compensation is applied than when no compensation is performed.

Such an obstacle is caused not only by the back-incident light from the optical viewfinder but also by stray light from another unexpected path (for example, when the aperture stop as the image-capturing light-blocking means fails and is not fully closed. The normal photographing is possible if the shutter is operating normally). In addition, if the detected defects were concentrated due to some system abnormality, the same problem as described above would occur.

SUMMARY OF THE INVENTION The present invention has been made in consideration of the above circumstances, and has as its object to solve the problem caused by erroneous detection of a defect, and to provide a high-performance device which does not cause deterioration in image quality due to an increase in pixel defects over time. It is to provide an imaging device.

[0008]

In order to solve the above-mentioned problems, an image pickup apparatus according to the present invention comprises an image pickup device, an image pickup optical system for inputting a subject image to the image pickup device, and an output from the image pickup device. Defect data detecting means for detecting pixel defect data relating to the image sensor; and reliability judging means for judging the reliability of the detection based on the output of the image sensor in the process of detecting the defect data by the defect data detecting means. And control means for stopping the detection of the defect data by the defect data detection means when the reliability judgment means judges that the reliability of the defect data detection is insufficient. .

An image pickup apparatus according to the present invention comprises: an image pickup device;
An imaging optical system for inputting a subject image to the imaging device; a defect data detection unit for detecting pixel defect data related to the imaging device based on an output of the imaging device; and a defect detected by the defect data detection unit. Defect correction means for performing defect correction processing on the output of the image sensor based on data; reliability determination means for determining the reliability of the detection in the course of defect data detection by the defect data detection means; Control means for prohibiting application of the defect data detected by the defect data detection means to the defect correction processing when the gender judgment means determines that the reliability of the defect data detection is insufficient. It is characterized by the following.

As described above, by determining the reliability of the detection based on the output of the image sensor in the process of detecting the defect data by the defect data detecting means, it is possible to detect a situation where the possibility of erroneous detection is high. . If it is determined that the reliability of the defect data detection is insufficient,
By performing control to stop detection of the defect data by the defect data detection unit or control to prohibit application of the defect data detected by the defect data detection unit to the defect correction processing, image quality due to erroneous detection of a defect is obtained. Problems such as deterioration can be solved.

The defect data detecting means includes:
A configuration in which a defect address which is an address of a pixel in which image information of the pixel should be invalidated is detected as the pixel defect data can be used. In this case, as the defect correction unit, the defect address is registered. It is possible to use a unit configured as a defect compensation unit that performs a compensation process on a pixel by the output of a neighboring pixel.

[0012] In particular, there is provided an imaging light blocking means for blocking incident light from the imaging optical system to the image pickup device, and this state is provided while the incident light to the image pickup device by the imaging optical system is blocked by the imaging light blocking means. When the detection of the pixel defect data is performed based on the dark output which is the output obtained in the step (a), the reliability determining means determines the average level of the dark output in the pixels in the predetermined area of the image sensor and the predetermined determination reference level. It is preferable that the reliability of the detection be determined based on the result of comparison with. This makes it possible to correctly determine the presence or absence of the influence of the back incident light from the optical finder.

[0013]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing a configuration of a digital camera according to an embodiment of the present invention.

In FIG. 1, reference numeral 101 denotes an imaging lens system including various lenses; 102, a lens driving mechanism for driving the lens system 101; 103, an exposure control mechanism for controlling the aperture and shutter device of the lens system 101; A low-pass and infrared cut filter; 105, a CCD color image sensor for photoelectrically converting a subject image; 106, a CCD driver for driving the image sensor 105;
A pre-processing circuit including a / D converter, etc .; 108, a digital processing circuit for performing various digital arithmetic processing such as gamma conversion; 109, a card interface; 110, a memory card; 111, an LCD image display system; Is shown.

In the figure, reference numeral 112 denotes a system controller (CPU) for comprehensively controlling each unit, 113 denotes an operation switch system composed of various SWs, and 114 denotes an operation display for displaying an operation state, a mode state, and the like. System, 115 is a lens driver for controlling the lens driving mechanism 102, 116 is a strobe as a light emitting means, 117 is an exposure control driver for controlling the exposure control mechanism 103 and the strobe 116, and 118 is various kinds of setting information and the like. A non-volatile memory (EEPROM) 119 is a power supply circuit that supplies operating power to each unit by a built-in battery (battery) or an external power supply input via an AC adapter.

The camera of this embodiment has a known single-lens reflex optical viewfinder. However, the optical path branching to the optical finder is performed by a half mirror (prism).
FIG. 2 shows the structure around the optical finder.

When the mechanical shutter 103a provided as an iris in the exposure control mechanism 103 is open,
The subject image input from the lens system 101 is input to the imaging surface of the CCD 105 through the half mirror (prism) 201 and is branched by the half mirror (prism) 201. The aerial images branched by the prism 201 and formed on the primary image forming surface (dotted line between the prism 201 and the plane mirror 203) are formed on the plane mirrors 203 and 2.
Relay by the secondary imaging lens 204, the secondary imaging lens 204
The aerial image re-formed by the camera is magnified and observed by the loupe lens 206. It is also possible to arrange a screen on either the primary or secondary imaging plane so that focus can be confirmed.

In this configuration, extra light may be input to the CCD 105 due to reverse incident light from the optical finder. If there is such reverse light blocking at the time of defect detection, there is a risk that the entire pixel area near the center of the CCD 105 is erroneously detected as a defective pixel. In order to prevent such back-incident light, it is preferable to provide an eyepiece shutter or the like for blocking back-incident light inside the loupe lens 206. Even in this case, the set position of the eyepiece shutter, etc. Depending on the situation, a similar problem occurs.

In the camera of the present embodiment, the system controller 112 performs overall control, and controls the exposure control mechanism 103 and the driving of the CCD image pickup device 105 by the CCD driver 106 to perform exposure (charge accumulation). And read out the signal, A / D convert the signal through the pre-processing circuit 107, take it into the digital process circuit 108, perform various signal processing in the digital process circuit 108, and then perform the card interface 1
09 to the memory card 110.

The system controller 112 comprises a microcomputer such as a CISC chip, for example.
A RAM 112a is provided as an internal memory. This R
AM 112a is a volatile memory such as an SRAM,
Even when the power switch of the camera is off, backup is performed as long as the battery or external power is supplied, and the stored contents are retained without being lost.

Further, the system controller 112 has functions related to defect detection and pixel defect compensation,
Memory control unit 11 for controlling writing / reading of data to / from EEPROM 118 and RAM 112a
2b and a defect data detector 11 for detecting pixel defect data by analyzing a signal from the CCD 105 obtained in a light-shielded state by the digital process circuit 118.
2c and a defect compensation control unit 112d for performing a pixel defect compensation process on a signal obtained from the CCD 105 at the time of actual imaging.
And a defect detection reliability determination unit 112e for determining the reliability of defect detection in the defect detection process by the defect data detection unit 112c.

The pixel defect compensation processing is performed by the defect compensation control unit 11
Based on the command from 2d, R
The process is executed in the digital process circuit 108 based on both the defect data read by the AM 112a and the defect data newly detected by the defect data detection unit 112c. In the initial stage (when the camera is shipped from the factory), only the initial defect data obtained by the inspection in the factory is E
Although stored in the EPROM 118, new defect data is additionally registered in the EEPROM 118 each time a defect is detected by the defect data detection unit 112c.

Hereinafter, camera control by the system controller 112 will be described focusing on processing directly related to detection and compensation of pixel defects according to the present invention. However, in this camera, the digital processing of the signal level obtained from the CCD 105 is performed with 8 bits (0 to 255). Except for the parts specially described later, the description will be made assuming normal temperature.

Prior to photographing, an exposure time required for photographing is set based on a manual setting or a photometric result. Next, the camera waits for a shooting trigger command for the main imaging, and upon receiving the command, performs exposure based on a predetermined exposure control value.
After the image signal is read out from the memory card and subjected to predetermined signal processing, it is recorded on the memory card 110. At this time, pixel defect compensation is performed for the defective pixel specified by the defect data.
Video signal processing up to recording after defect compensation,
It is used per se as necessary according to its necessity. For example, color balance processing, conversion to a luminance-color difference signal by matrix operation or inverse conversion processing, false color removal or reduction processing by band limitation, γ conversion, etc. Representative types of non-linear processing, various information compression processing, and the like.

The defect compensation in the camera of the present embodiment employs the well-known "complementation of a pixel in which a defect address is registered with a neighboring pixel". Of the pixels, four pixels closest to the defective pixel: In the case of an RGB Bayer array, for example, four G pixels, R,
For (or B), the average value of the four pixel information of four R (or B) pixels located next to each other with one G interposed therebetween instead of directly adjacent in the four directions of up, down, left, and right) is applied instead. Things have been adopted.

The camera detects a defect when necessary, and additionally updates the defect data based on the result. When performing defect detection, dark charge level data obtained by shading is obtained, and reliability of detection is determined prior to level determination and mutual comparison (“defect detection” by) for each pixel. That is, "an average value of outputs (dark charge levels) of 64 × 64 pixels at the center of the imaging area is obtained. This is 5 (5/255 =
If it exceeds about 2%), it is determined that the reliability of detection is low. In this case, the defect detection is stopped. That is, in the case of a light-blocking defect such as reverse incident light, spot-shaped light irradiation occurs particularly at the center, and this is detected. In this case, since the level of a certain area is raised on average, it can be detected as described above. (At least for whatever reason,
As described above, when the level of a certain area is raised as a whole, it is inappropriate to complement all the areas with neighboring pixels, since this area is filled with a substantially constant value, which is inappropriate. Judgment is low. Therefore, in this case, the subsequent processing is performed on the assumption that no defect has been detected by the new detection. In this case as well, at least the defect data already registered in the EEPROM 118 is effective, and the defect is compensated for it. Therefore, extreme image quality deterioration does not occur, and fatal image quality deterioration due to erroneous compensation is prevented. . It should be noted that a mode may be used in which the address is acquired by performing “defect detection” once, but is not used (prohibition of application) in actual defect compensation. In this regard, as is clear from the above description, this does not necessarily mean that the compensation for the detected pixel is necessarily prohibited, but when the defective pixel is redundantly adopted by another method, this is not considered. It is acceptable.

Here, the premise of the defect data additional registration processing according to the present embodiment will be described.

That is, recent studies by the present inventors have revealed that some of the defects may be referred to as “flashing defects”. This is because, when image pickup (charge accumulation and readout) is repeated under exactly the same image pickup conditions including temperature and exposure (accumulation) time, for example, the same pixel sometimes becomes white defect (excessive dark charge). In other words, the behavior is as if a white defect (excessive dark charge) is blinking, for example, or a normal signal is output once.

Although no clear theory has yet been found for the cause of the blinking defect, the following findings have been obtained at least phenomenologically. That is, this blinking seems to include a certain probabilistic element, has no particular periodicity or dependence on the number of readouts, and blinks during repeated imaging in a relatively short period (short periodicity: as described above). No periodicity has been found in this phenomenon, but it has been found that some metaphorically use the term "period." Up to this point, it is possible that extremely long-period flickering defects were also included in the late defects that were conventionally considered to be destructive (non-returning) phenomena due to the effects of natural radioactivity and incoming cosmic rays. On the other hand, it has been pointed out that many short-period flickering defects occur lately.

In the presence of such various blinking defects, a conventional simple defect registration method (using a defect address registered at a factory) or a simple immediately preceding detection method (for example, when the power is turned on, etc.). Performing the detection and using the newly obtained defective address) is obviously ineffective. Further, even if both are used together, it is not sufficient by itself, and it is essential to additionally register and use a newly detected defect address. The present embodiment is based on such an additional registration system.

Next, referring to FIG.
8 and the defect data read / write processing will be described.

The EEPROM 118 has two storage areas, a storage area A and a storage area B, as shown in the figure.
The storage area B stores initial defect data relating to the CCD 105 obtained before shipment from the factory. This storage area B
Is a read-only area to prevent destruction of the initial defect data, and writing to the storage area B is prohibited. The storage area B is assigned a storage size capable of registering defective pixel addresses of, for example, 512 to 1024 pixels as initial defect data.

The storage area A is a storage area for additionally registering the defect data newly obtained by the defect detection processing by the defect data detection section 112c after the factory shipment. The storage area A is assigned a storage size capable of registering defective pixel addresses of, for example, 128 pixels. In the initial state after factory shipment, no defect data is stored in the storage area A. That is, the storage area A is a dedicated area used for registering a late defective pixel detected by the defective data detection unit 112c.

The RAM 112a has three storage areas C, D, and E as shown. The storage area D is an area for storing initial defect data read from the storage area B of the EEPROM 118, and the storage area C is for storing additionally registered defect data read from the storage area A of the EEPROM 118. Area. The storage sizes of the storage areas C and D are the same as the storage areas A and B, respectively.

The process of reading the contents of the storage areas A and B of the EEPROM 118 and writing the contents to the storage areas C and D of the RAM 112a is performed, for example, when the power switch is first turned on after the battery is inserted. Connection) is performed. As described above, the stored contents of the RAM 112a will not be lost when the batteries are inserted unless the batteries run out, but once the batteries are removed for battery replacement or the like, the stored contents of the RAM 112a may be lost. become. For this reason, once the battery is inserted,
118, the contents of the storage areas A and B are copied to the storage areas C and D in the RAM 112a. Thereafter, the reading from the EEPROM 118 is not performed until the next time the battery is inserted and the power switch is turned on. Without doing
Defect compensation is performed using the defect data copied on the RAM 112a. As described above, in this embodiment, when the battery is mounted and the power switch is turned on, the EEPROM 11 is turned on.
8 to control the read operation of the defect data from
The reading from the OM 118 is performed only once after the battery is mounted.

The storage area E on the RAM 112a is used for storing addresses of defective pixels detected by the defect detection operation by the defect data detection section 112c. The storage area E is assigned a storage size capable of registering defective pixel addresses of, for example, 32 pixels.

The defect detection by the defect data detection unit 112c is performed on the remaining pixels excluding the defective pixels registered as the initial defect data. For this reason, the defect data stored in the storage area E is only the address of the late defect generated after the factory shipment. Defect data detector 1
12c, each time a defect detection operation is performed, new defect data acquired by the defect detection operation is stored in the storage area E.
And the new defect data written in the storage area E is additionally registered in the storage area A of the EEPROM 118. When the additional registration data already exists in the storage area A, only the non-overlapping defective pixel addresses among the defective pixel addresses detected by the defect data detection unit 112c are added to the storage area A.

Defect detection and addition of defect data to the EEPROM 118 executed in response to the defect detection are performed, for example, in 2 steps.
It is preferable to perform it at the time of power-on at a rate of about once every four hours. In this case, if power is turned on after 24 hours have passed since the previous defect detection and data addition, new defect detection and data addition are performed at that point. Even when the power is not turned on, a new defect may be detected and data may be additionally written 24 hours after the last defect detection and data addition in a state where the power is turned on, that is, in a normal operation state. .

The defect compensation processing performed by the defect compensation control unit 112d at the time of actual imaging takes into account not only the defect data in the storage areas C and D read from the EEPROM 118 but also new defect data stored in the storage area E. And executed. As a result, even if reading from the EEPROM 118 is limited to only once after the battery is inserted, defect compensation based on the latest detected defect is always performed. Although defective pixel addresses may overlap in the storage area C and the storage area E, the image quality is not affected even if the defect compensation processing is performed twice on the same pixel. In addition, every time a defect is detected, new defect data written in the storage area E is added to the storage area A of the EEPROM 118 in a state where duplication is eliminated.
Even if the storage content of 12a is lost, it is possible to read out all the defect data including the latest additional registration data from the EEPROM 118.

FIG. 4 shows the structure of defect data stored in each of the storage areas A and B. Storage area A,
In both cases, the defect data registered in the storage area is the number of registrable data: the maximum number of registrable pixels (n) The number of registered defects: the number of pixels actually registered as defective pixels Data Area: X. of each defective pixel It has a structure called Y address. In the data area, the maximum number of pixels that can be registered (n = 128 for area A, n = 512 or 1 for area B)
024) of pixel address registration areas.

Next, referring to the flowchart of FIG.
The procedure of the defect detection operation will be described.

First, the system controller 112 shields the light receiving surface of the image pickup device from light with the shutter device included in the exposure control mechanism 103, and then performs test imaging in the light shielded state (step S101). That is, in the dark, the CCD driver 106 performs a charge accumulation operation for the longest exposure time Tmax of the camera (setting is arbitrary: the example value 5 s here) to read out a test imaging signal (dark output signal) and store it in the digital process 108 I do. Digital process 10
8, first, under the control of the defect detection reliability determination unit 112 e, in order to determine whether there is a high possibility of erroneous detection such as back incident light from the finder,
The average output value of 64 × 64 pixels at the center of the imaging area in D105 is calculated (step S102), and the presence or absence of a light-shielding failure state depends on whether the output average value exceeds 5 (5/255 = about 2%). Is determined (step S10).
3). If the average output value exceeds 5 (5/255 = approximately 2%), it is determined that a light-shielding defect, that is, a defect such as reverse incident light from the optical finder or the shutter device 103a not being fully closed has occurred. And the defect detection process is stopped.

If the average output value is 5 or less (5/255 = about 2%), a defect detection process is performed. In this case, first, “detection defect compensation processing” is performed under the control of the defect compensation control unit 112d (step S104). The “detection defect compensation process” is performed for the purpose of excluding defective pixels registered as initial defect data from detection targets of the defect detection operation, and is performed based on the initial defect data copied to the storage area D. Then, the interpolation processing is performed by the nearest same color pixel.

Although it is conceivable to perform "detection defect compensation processing" for the purpose of eliminating duplicate detection with respect to the additionally registered defect data copied to the storage area C, the additional registration defect data is compared with the initial defect data. Since the reliability of the data is not always sufficient, it is preferable that the defect compensation processing for detection is performed only on the defective pixel specified by the initial defect data.

Next, by analyzing the image information after the defect compensation based on the initial defect data by the digital process 108, defect detection for selecting a pixel having a large dark output level as a defective pixel is performed (step S1).
05). As described above, the “detection defect compensation process” performs the defective pixel detection process on the pixel information after the compensation process is performed based on the initial defect data.
For a pixel that has already been registered as a defective pixel address, defect detection is performed on the compensated data. Therefore, it is possible to prevent a defect that a pixel registered as a defective pixel is detected again as a defect each time it is detected, and it is possible to detect only unregistered late defects. Become.

In the defect detection in step S105, instead of the level comparison method of checking each output level for all data of effective output pixels and comparing it with a reference detection level, the upper 32 dark output levels are used in descending order. A method of simply selecting a pixel is used. That is,
Regardless of the detection level, the worst 32 pixels having a large dark output level are determined as defective pixels. Since the number of detected pixels is limited to 32, the image quality does not break down due to an excessive increase in the number of detected pixels in which the number of pixels to be complemented is equal to or larger than the number of pixels permitted by the defect compensation processing. Further, even if the CCD 105 is an element having a relatively light defect, at least the worst 32 pixels can be detected, so that there is no problem such as a failure to detect a defective pixel.

In the worst 32 pixel selection operation, a buffer for 32 pixels as shown in FIG. 6 is used. For the first 32 pixels, a pair of the pixel address and the dark output level is unconditionally registered in the buffer.
From the 33rd pixel, each pixel is compared with the minimum dark output level currently stored in the buffer,
It is determined whether or not to register in the buffer. in this way,
The pixel selection operation can be performed by simple arithmetic processing.

It should be noted that the pixel having the maximum dark output level has the same value of 3
When there are more than two pixels, exceptionally, a process of appropriately selecting a pixel to be registered from each of the pixels having the same maximum value so that the detected pixels are dispersed at four corners of the screen or the like is performed. I just need. In practice, of course, a level determination that a pixel having a dark output level of almost zero is not regarded as a defective pixel may be used together.

Next, the 32 worst defective pixel addresses selected by the pixel selection operation are registered in the storage area E (step S106). Then, the overlap with the defective pixel address read into the storage area C is checked, and only the non-overlapping defective pixel address is additionally written into the storage area A of the EEPROM 118 (step S10).
7).

Next, referring to the flowchart of FIG.
The imaging / recording operation at the time of actual imaging will be described.

First, prior to photographing, an exposure time necessary for photographing is set based on a manual setting or a photometric result. When a photographing trigger command for main photographing is received, exposure based on a predetermined exposure control value is performed. Is read out (step S111). After the A / D conversion, the imaging signal is input to the digital process 108, where a defect compensation process is performed (step S112). This defect compensation processing is basically performed based on the sum of defective pixel addresses stored in the storage areas C, D, and E, respectively. Specifically, the defect compensation based on the defective pixel address of the storage area C and the storage area D
And the defect compensation based on the defective pixel address of the storage area E may be executed. The algorithm of the defect compensation process itself is an interpolation process using the same nearest-neighbor pixels as in the “defect compensation process for detection”, and is realized by the same arithmetic processing unit as in the case of the “defect compensation process for detection”.

On the other hand, if the defect detection is executed and the defective pixel address is added to the storage area E even if the reliability of the previous defect detection is judged to be insufficient, By removing E, a defect compensation process based on the sum of the defective pixel addresses stored in each of the storage areas C and D is performed (step S112 '). Also in this defect compensation processing, the interpolation processing using the nearest same color pixel is performed, and the interpolation processing for the pixel already registered as the defective pixel is correctly performed. In other words, the defect compensation processing is performed as usual for the pixels that are registered as defective pixels in a manner overlapping with the storage area E.

Then, step S112 or S11
After performing various image processing on the image information after the defect compensation by 2 ′ (step S113), the memory card 11
0 is recorded (step S114).

Next, referring to the flowchart of FIG.
A flow of a series of processes after battery insertion is detected will be described.

When a new battery is inserted due to battery replacement or the like (or when a power adapter is connected with no battery inserted), the system controller 112 is activated and an initial operation is started ( Step S121). Then, the system controller 112
Becomes a standby mode in which the power switch is turned on. When the power switch is turned on by the user (step S122), the system controller 112 controls the power circuit 119 to start power supply to each part in the camera, and sets the camera to a power-on state (step S1).
23). If this power-on is the first power-on after the battery is inserted (YES in step S124), the system controller 112 reads the defect data in the storage areas A and B from the EEPROM 118 (step S12).
5) Write it to the storage areas B and C of the RAM 112a (step S126).

The system controller 112 has a built-in timer. When the timer detects that 24 hours have passed since the last defect detection or when the battery was inserted (Y in step S127).
ES), the defect detection operation described with reference to FIG. 5 is started, and detection of a late defective pixel and additional registration in the EEPROM 118 are performed (step S128).

Thereafter, the system controller 112
The mode is a standby mode for a shutter trigger operation, a power switch OFF, and the like. When the shutter trigger operation (shooting trigger command) is performed (YES in step S129), the system controller 112 executes the imaging / recording operation described in the flowchart of FIG. 7 (step S13).
0). If the power switch is turned off (YES in step S131), the system controller 112
Controls the power supply circuit 119 to stop the power supply to each part in the camera and to turn off the camera (step S1).
32) The standby mode is set to wait for the power switch to be turned on.

As described above, in the present embodiment, C
In an image pickup apparatus that detects a pixel defect of the CD 105 and compensates for a defective pixel of the CCD 105 based on the defect data obtained thereby, to detect a situation where there is a high possibility of erroneous detection such as reverse incident light from a finder. Defect control based on erroneous detection information by using control such as stopping the defect detection or prohibiting the application of the defect data detected in a situation where there is a high possibility of erroneous detection to the defect correction processing. , The image quality can be prevented from being degraded.

The present invention is not limited to the above-described embodiment, and can be variously modified in the implementation stage without departing from the gist of the invention. For example, in the above embodiment, the defect detection, the registration of the defective pixel, the compensation processing, and the reliability determination processing relating to the defect detection have been described with respect to a so-called white defect. , Compensation processing, and reliability determination processing relating to defect detection. At the time of detecting a black defect, white light input to the imaging surface may be performed by some method instead of the light shielding state.

In the above-described embodiment, the reliability is determined by using the average value of “the output of 64 × 64 pixels at the center of the imaging area”. However, “average” is one example.
By adopting “average level” as one parameter in addition to “addition average”, “geometric average”, and the like, the effect can be obtained with a very simple criterion. Of course, any other reliability determination method such as analyzing the continuity of the dark charge level for each pixel may be used. Further, in the above description, the effect is extremely easily obtained by focusing only on the limited area in the central portion. However, for example, a large number of similar areas may be provided so as to fill the entire screen. Although it is more complicated than the above example, there is an advantage that the number of troubles that can be dealt with, such as the influence of stray light due to various causes and cases due to other causes, is significantly increased.

In the above description, “defect compensation” using complementation with neighboring pixel data is taken as an example. However, the present invention is not limited to this, and includes general subtraction correction such as subtraction of a dark charge level for each pixel. It goes without saying that the present invention for judging the reliability of detection for "defect correction" and not applying the defect correction when the reliability is low is similarly effective. Furthermore, in this example, a digital still camera has been described as an example, but the present invention can be similarly applied to a digital movie.

Further, the above embodiments include inventions at various stages, and various inventions can be extracted by appropriately combining a plurality of disclosed constituent elements.
For example, even if some components are deleted from all the components shown in the embodiment, the problem described in the column of the problem to be solved by the invention can be solved, and the effects described in the column of the effect of the invention can be solved. Is obtained, a configuration from which this configuration requirement is deleted can be extracted as an invention.

[0063]

As described above, according to the present invention,
The problem caused by the erroneous detection of the defect can be solved, and the image quality can be prevented from deteriorating by performing the defect compensation based on the erroneous detection information.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of an electronic camera according to an embodiment of the present invention.

FIG. 2 is an exemplary view showing a structure around an optical finder in the electronic camera according to the embodiment.

FIG. 3 is an exemplary view for explaining a structure of an EEPROM used in the embodiment and a process of reading / writing defective data;

FIG. 4 is an exemplary view for explaining a structure of defect data registered in an EEPROM in the embodiment.

FIG. 5 is an exemplary flowchart for explaining the procedure of a defect detection operation in the embodiment.

FIG. 6 is a diagram for explaining an arithmetic process of a worst predetermined number selection process performed in the defect detection operation of FIG. 5;

FIG. 7 is an exemplary flowchart for explaining the procedure of an imaging / recording operation in the embodiment.

FIG. 8 is a flowchart showing a flow of a series of processes after the battery insertion is detected in the embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 101 ... Lens system 102 ... Lens drive mechanism 103 ... Exposure control mechanism 104 ... Filter system 105 ... CCD color image sensor 106 ... CCD driver 107 ... Preprocess circuit 108 ... Digital process circuit 109 ... Card interface 110 ... Memory card 111 ... LCD image Display system 112: System controller (CPU) 112a: RAM 112b: Memory control unit 112c: Defect data detection unit 112d: Defect compensation control unit 112e: Defect detection reliability determination unit 118: EEPROM 119: Power supply circuit

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Takayuki Kijima 2-43-2 Hatagaya, Shibuya-ku, Tokyo Inside Olympus Optical Industry Co., Ltd. (72) Hideaki Yoshida 2-43-2 Hatagaya, Shibuya-ku, Tokyo Olympus Optical Co., Ltd. F term (reference) 5C024 CX21 CX22 CX23 CX24 CX25 EX34 HX14 HX57

Claims (5)

[Claims] An image pickup device, an image pickup optical system for inputting a subject image to the image pickup device, defect data detection means for detecting pixel defect data on the image pickup device based on an output of the image pickup device, A reliability determination unit that determines the reliability of the detection based on an output of the image sensor in a process of detecting the defect data by the defect data detection unit; and the reliability determination unit has insufficient reliability of the defect data detection. An image pickup apparatus, comprising: a control unit for stopping the detection of the defect data by the defect data detection unit when it is determined that there is a defect data. 2. An image pickup device, an image pickup optical system for inputting a subject image to the image pickup device, defect data detection means for detecting pixel defect data on the image pickup device based on an output of the image pickup device, Defect correction means for performing a defect correction process on the output of the image sensor based on the defect data detected by the defect data detection means; and based on the output of the image sensor in the process of detecting the defect data by the defect data detection means. Reliability determination means for determining the reliability of the detection, and the defect data detected by the defect data detection means when the reliability determination means determines that the reliability of the defect data detection is insufficient. And a control unit for prohibiting the application to the defect correction processing. 3. The defect data detecting means detects, as the pixel defect data, a defect address which is an address of a pixel for which image information of the pixel is to be invalidated. 3. The image pickup apparatus according to claim 1, wherein the image pickup apparatus is configured as a defect compensating unit that performs a compensation process based on an output of a neighboring pixel for a pixel whose address is registered. 4. An imaging light blocking means for blocking incident light from the imaging optical system to the image pickup device, wherein the defect data detection means receives light incident on the image pickup device by the imaging optical system by the image pickup light shielding means. 4. The apparatus according to claim 1, wherein the pixel defect data is detected based on a dark output obtained in this state while blocking light. 5. An imaging device according to any one of the preceding claims. 5. The reliability judging means judges the reliability of the detection based on a comparison result between an average level of dark output in a pixel of a predetermined area of the image sensor and a predetermined judgment reference level. The imaging device according to claim 4, wherein the imaging device is configured.