JP2002290837A - Black defect detecting device for solid state image sensing device and imaging apparatus, and black defect detecting method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To accurately detect a black defect of a solid state image sensing device. SOLUTION: The solid state image sensing device 3 is provided with a plurality of kinds of optical filters having sensitivity differences with wavelength characteristics of incident light for respective photodetecting elements. Further, a gain coefficient setting means 24 is provided with sets a predetermined gain coefficient for each optical filter when a photodetecting element having a black defect is detected by monitoring the signal level outputted from the solid image pickup element when plane light is made incident. The output signal levels of photodetecting elements corresponding to the respective optical filters are multiplied by individual gain coefficients to make level corrections so that the output signal levels obtained from photodetecting elements having no black defect have the same prescribed level is irrelevantly to the kinds of the optical filters. The photodetecting element having the black defect can be decided from the difference between the output signal level of the element and the prescribed level.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a technique for accurately detecting a black defect in a solid-state imaging device.

[0002]

2. Description of the Related Art Detecting defective pixels relating to a solid-state image pickup device includes detecting white defects (detecting defective pixels at a so-called white point, and detecting defective pixels that are brighter than normal luminance with respect to the amount of incident light) and black. Defect detection (a so-called black dot defective pixel detection, which detects a defective pixel darker than normal luminance with respect to the incident light amount). The latter detection method is a solid-state image sensor when a white object is photographed. A method is known in which the signal level of the output obtained from is compared with a predetermined reference level.

FIG. 7 is an explanatory diagram relating to the essential points of the conventional detection method, and shows a bar graph in which the output signal levels of the solid-state imaging device are arranged along the horizontal axis. In this example, a complementary color filter (a filter array in which various color filters are arranged) is used, and “Mg” in the figure represents magenta and “G” represents green.

Further, "BLK" represents a black level, and "LK"
“sh” indicates a threshold value (defect determination reference level) for defect detection, and it is assumed that a defect occurs in the element with respect to a signal output indicated by an arrow “E1” or “E2”. That is, at the position indicated by the arrow “E1”, the signal level indicated by the broken line should be originally obtained, but as shown in the figure, only an output of a level slightly higher than “Lsh” is obtained (see the arrow “D1”). Also, at the position indicated by the arrow "E2", the signal level indicated by the broken line should be originally obtained, but as shown in the figure, only an output with a level slightly lower than "Lsh" is obtained (arrow "E2"). D2).) Therefore, a defect occurs at each position.

[0005]

However, in the method of setting a single judgment reference level and comparing the signal level with the signal level as in the above-mentioned method, the following method is required to accurately detect a black defect. There's a problem.

At the position indicated by the arrow "E2", a defect is detected because the signal level is smaller than the threshold value Lsh.
At the position indicated by the arrow "E1", no defect is detected because the signal level exceeds the threshold value Lsh. That is, the defect level (a level indicating the degree of defect, which is indicated by an arrow “D1” in FIG. 7)
reference. ) Is large and the defect level (arrow “D” in FIG. 7)
2 ". ), No defect is detected in the former case simply because the signal level exceeds the threshold value Lsh. (Even if the defect level is high, it is difficult to detect a defect if the original signal level is high.) ), It is difficult to detect black defects with high accuracy in a solid-state imaging device using a color filter having a sensitivity difference.

Accordingly, an object of the present invention is to accurately detect a black defect relating to a solid-state imaging device.

[0008]

In order to solve the above-mentioned problems, the present invention provides a gain coefficient setting means for setting a predetermined gain coefficient for a plurality of types of optical filters, and a light receiving means corresponding to each of the optical filters. The output signal level of the element is multiplied by each different gain coefficient so that the level of the output signal obtained from the light-receiving element without black defects is the same specified level regardless of the type of optical filter. The image processing apparatus further includes a correction unit for correcting the image and a determination unit for determining a black defect based on a difference between a prescribed level and a level of an output signal obtained from a light receiving element having the black defect.

Therefore, according to the present invention, the level of the output signal obtained from the light receiving element having no black defect becomes the same specified level regardless of the type of the optical filter, and the level of the output signal obtained from the light receiving element having the black defect is obtained. Based on the fact that the level of the output signal obtained indicates a level different from the specified level, it is possible to accurately detect the position and the degree of the black defect.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention is directed to a light receiving element having a black defect by monitoring a signal level output from a fixed image pickup element upon which plane light (plane wave light) is incident on a solid state image pickup element. The present invention relates to a black defect detection device and a black defect detection method for detecting the image, or an imaging device using the same.

[0011] The solid-state imaging device is premised on that a plurality of types of optical filters having different sensitivities due to the wavelength characteristics of incident light are provided for each light receiving device. As for the optical filter, regarding its wavelength range,
In the case of the visible light region, a color filter (color filter or color separation filter) is used. However, the present invention is not limited to this, and can be widely applied to an ultraviolet filter, an infrared filter, and the like.

FIG. 1 shows an example of a configuration in which the present invention is applied to a camera signal processing section constituting an imaging device 1 using a black defect detection device. In this example, color filters of complementary color coding (cyan “Cy”, yellow “Y”
e), a CCD (charge coupled device) type solid-state imaging device using a mosaic color filter array including green “G” and magenta “Mg”, but primary color coding (R
Of course, the present invention can be applied to an image sensor using a GB) color filter, and can be applied to an image sensor such as a MOS (metal oxide semiconductor) type as well as a CCD type. Further, the present invention is not limited to the single-plate type, and can be applied to a two-plate type and the like.

The camera signal processing unit has the following constituent elements (the numbers in parentheses indicate the signs).

A lens system and an iris (2); a solid-state image pickup device using a color filter as an optical filter (3); a sample hold and automatic gain control circuit (4); an analog / digital conversion circuit (5); Correction circuit (6) Signal processing circuit (7) Control unit (8).

In the figure, the sample hold is represented by "S /
H "," AGC "for automatic gain control, and" A / D conversion "for analog / digital conversion.

Lens system and iris 2 (so-called optical system)
Constitutes an imaging system together with the solid-state imaging device 3, and receives a plane light when a black defect is detected.

The solid-state imaging device 3 converts light from a subject through an optical system from an amount of light received according to the sensitivity characteristics of a filter array (in this example, a complementary color filter) into an electric signal.

Sample hold and automatic gain control circuit 4
Is a circuit necessary for stabilizing the signal level by automatically performing sampling (sample extraction) relating to the output signal of the solid-state imaging device 3 and gain adjustment, and the output signal is output to a subsequent analog / digital conversion circuit. 5 is sent.

The digital signal output quantized by the analog / digital conversion circuit 5 is sent to a signal processing circuit 7 after passing through a defect detection and correction circuit 6.

The defect detection and correction circuit 6 detects a black defect based on the output signal of the analog / digital conversion circuit 5,
In addition to performing defect detection including white defect detection, he is in charge of correction processing according to the detection result.

The signal processing circuit 7 performs luminance (Y) signal processing and chroma (C) signal processing on the input signal.
After performing various processes including encoding and the like, a composite video signal (video signal) is output.

The control unit 8 is constituted by using a microcomputer 8a and a nonvolatile memory 8b. The microcomputer 8a stores a defect detection result in the nonvolatile memory 8b or a nonvolatile memory 8b when correcting a defect. Has a role of setting a defect correction address (information of a defect position) by reading out the data stored in the memory and sending it to the defect detection and correction circuit 6. For the nonvolatile memory 8b, for example,
An EEPROM (electrically erasable and writable read-only memory) is an example. However, the storage means is not limited to this as long as data can be retained when power supply is stopped. Another memory (for example, a volatile memory having a backup function) A memory or the like.) Or an auxiliary storage device using a recording medium may be used.

The configuration of the defect detection and correction circuit 6 includes, for example, the following components as shown in FIG. 1 (numbers in parentheses indicate symbols).

A circuit for detecting a black defect (9) A circuit for detecting a white defect (10) A selector (11) A defect address memory (12) A correction signal generation circuit (13) A defect correction circuit (14).

The circuit 9 for detecting a black defect is a central part of the detection of a black defect, and the detection result is sent to a white defect detection circuit 10 via a selector 11. The configuration and operation will be described later in detail, but embodiments of the present invention include the following modes.

(I) The light-receiving element having a black defect is specified by using the signal indicating the result of the black defect detection as it is, and its position information is stored in the storage means, and is read out from the storage means when the defect is corrected. A timing signal for defect correction is generated based on the obtained information to perform defect correction. (Ii) The detection signal of the black defect is converted into a detection signal corresponding to a white defect without using the signal indicating the detection result of the black defect as it is. A mode in which the means for detecting white defects and correcting white defects is diverted by conversion.

First, (i) is a mode in which a black defect is detected and the black defect is corrected based on the result. For example, when a defective pixel is found, by performing replacement with the pixel output one pixel before the defective pixel, an output signal obtained from a defective light receiving element can be ignored or obtained from a pixel output of an adjacent pixel. Processing such as substituting with a calculated value is performed. However, in this embodiment, it is necessary to perform the white defect detection and correction separately from the black defect detection and correction.

On the other hand, according to the form (ii), the difference between black and white is the relative relationship between the signal levels. That is, if the direction of the level axis is reversed for the black level and the white level, the black and white are inverted. By paying attention to the relationship described above, the detection signal of the black defect is converted into the detection signal corresponding to the white defect, so that the black defect can be detected using the mechanism of the white defect detection means as it is. That is, the position of the light receiving element is identified by regarding the black defect as a white defect by signal conversion,
When the position information is stored in the storage means, and a defect correction is performed by generating a timing signal for defect correction based on the information read from the storage means at the time of defect correction, the black defect is corrected as a result. Become. Therefore, there is an advantage that the circuit configuration can be simplified by using the white defect detection circuit and the white defect correction circuit, and the cost can be reduced.

The selector 11 selects either the output signal of the analog / digital conversion circuit 5 or the signal from the black defect detection circuit 9 and sends it to the subsequent white defect detection circuit 10. That is, when a black defect is detected, the circuit 9 for detecting a black defect is used.
When a white defect is detected, a signal that does not pass through the black defect detection circuit 9 is selected.

The white defect detection circuit 10 is a circuit for specifying a light receiving element having a white defect, and has a known configuration. For example, a comparison circuit (comparator) for comparing a signal level with a predetermined threshold for defect determination, and an address for specifying a position of a defective pixel (a position of a light receiving element on a solid-state imaging device) from the result of the comparison circuit A detection circuit, a sorting circuit for rearranging in order according to the size of the defect level, and the like are provided. In this example, (ii)
Therefore, the white defect detection circuit 10 is used even when a black defect is detected. That is, this circuit also constitutes a black defect detection device together with the above-mentioned black defect detection circuit 9.

The defect address memory 12 stores position information (address) of the detected defect on the solid-state imaging device. That is, the memory stores the data from the white defect detection circuit 10 and sends the storage data read from the memory to the correction signal generation circuit 13 under the control of the microcomputer 8a. In this example, since the configuration of (ii) is adopted, this memory is commonly used in white defect detection and black defect detection.

The correction signal generation circuit 13 is a circuit for generating a defect correction signal (timing signal) based on data sent from the defect address memory 12.
The signal is sent to the defect correction circuit 14.

The defect correction circuit 14 is arranged between the analog / digital conversion circuit 5 and the signal processing circuit 7, receives a defect correction signal from the correction signal generation circuit 13, and receives an output signal of the solid-state imaging device 3. To perform defect correction. In this example, since the configuration (ii) is adopted, the present circuit is commonly used in white defect detection and black defect detection. Further, regarding the defect correction method, the output value of the light receiving element at the position where the defect is detected is replaced with the output value of a non-defective element at the nearby position (normal pixel output value), or the defect at the nearby position is replaced. Since various methods such as substituting with the calculation result based on each output value of the element group having no element can be cited, and the method does not matter as far as the present invention is concerned, the description is omitted.

Before describing the configuration of the black defect detection circuit 9 shown in FIG. 2, a black defect detection method will be described with reference to FIGS.

FIG. 3 shows an analog / digital conversion circuit 5
An example of the image output level of the solid-state imaging device 3 (color-difference line-sequential system) converted by the above is shown in a bar graph arranged along the horizontal axis (corresponding to the horizontal scanning direction of pixels). The signal levels shown in the figure alternately indicate levels corresponding to a G (green) color filter and a Mg (magenta) color filter. Also, the arrow “E1”,
It is assumed that the element has a defect with respect to the signal output indicated by “E2”, and the position (M
In g), the signal level indicated by the broken line should be originally obtained, as in the case of the output level having passed through the other Mg filters, but is smaller than the other output levels (the defect level is indicated by an arrow " D1 "). Also, the arrow "E
At the position (G) indicated by "2", the signal level indicated by the broken line should be originally obtained, as in the case of the output level after passing through the other Mg filters. (The defect level is indicated by an arrow “D2”).

Note that "BLK" in the figure indicates a black level.

FIG. 4 shows a graph obtained by subtracting "BLK" shown at the black level from the graph shown in FIG. That is, the black level “BLK” is used as the reference of the origin level.

FIG. 5 shows a state after each of the signal levels shown in FIG. 4 is multiplied by a predetermined gain coefficient.

For example, in complementary color coding, Cy,
The gain coefficients for the Ye, G, and Mg color filters are respectively “KCy”, “KYe”, “KG”, and “KMg”, and the output signal level of the light receiving element passing through each color filter is “VCy”. , "VYe", "VG", "VM
g ”,“ KCy × VCy ”,“ KYe × VYe ”,“ KG
× VG ”and“ KMg × VMg ”are respectively calculated to perform level correction.

In FIG. 5, for convenience of explanation, “KG = 2”,
Since each coefficient is selected as “KMg = 1”, the level of the imaging output level (the output level by the light-receiving element having no black defect) having passed through the G filter is doubled to the specified level (see FIG. "LVL"). The imaging output level (the output level of the light receiving element having no black defect) after passing through the Mg filter is the same level. That is, the specified level “LVL” is specified as the level of the output signal related to Mg having no black defect.

As described above, a predetermined gain coefficient is set for a plurality of types of optical filters, and a pixel output value corresponding to each optical filter, that is, an output signal level of a light receiving element corresponding to each optical filter, is set. By multiplying each of the gain coefficients to correct the difference between each output signal so that the sensitivity characteristics of each optical filter become uniform, the level of the output signal obtained from the light-receiving element having no black defect is determined by the type of optical filter. It can be seen that the same specified level LVL is obtained regardless of the above. In other words, when there is no black defect, each gain coefficient is determined in advance so that the signal level becomes the same specified level LVL.

On the other hand, regarding the output signals obtained from the light receiving element having the black defect, arrows "F1" and "F
As shown in “2”, the level is different from the specified level LVL. That is, in this example, as can be seen from the set value of the gain coefficient, the defect level (LVL−KMg × VMg = LVL−VMg) of Mg indicated by the arrow “F1” is the arrow “E1” in FIGS. Is equal to the defect level shown in
The defect level (LVL−G) of G indicated by the arrow “F2”
(KG × VG = LVL−2 × VG) is higher than the defect level indicated by the arrow “E2” in FIGS.

As described above, it can be seen that the signal level of the light receiving element having a black defect is not equal to the specified level LVL.

FIG. 6 shows the result of setting the specified level LVL to the white level and subtracting each signal level shown in FIG. 5 from the level, and the arrows "D1" and "D2" in FIG. ”Indicates an operation result corresponding to each of the defect levels indicated by the arrows“ D1 ”and“ D2 ”.

That is, the defect level of the element having a black defect is extracted by the above-described calculation (the same as the level relationship of each signal when the level axis is set in the opposite direction with respect to the level LVL as the reference level in FIG. 5). That is, it is equivalent to performing the level inversion based on the white level.)

As described above, the image output related to the black defect is converted into a signal corresponding to the image output related to the white defect and output. That is, in FIG. 5, at the positions indicated by the arrows “F1” and “F2”, it can be considered that each signal level has not reached the specified level LVL because a white defect has occurred. Although it depends on the black defect, the above-mentioned prescription can convert the black defect detection processing to the white defect detection processing.)

FIG. 2 shows a configuration example of the circuit 9 for detecting a black defect, and includes the following components (the numbers in parentheses indicate symbols).

A first stage subtraction circuit (15) A multiplication circuit (16) An output stage subtraction circuit (17) An average value detection circuit (18) A black level setting section (19) A gain coefficient setting section (20) A selector (21) a white level setting unit (22) a sequencer (23).

In this circuit, a signal from the analog / digital conversion circuit 5 (for example, see FIG. 3) is sent to a subtraction circuit 15. Then, as described with reference to FIG. 4, here, the black level BLK is calculated from the level of each signal.
Is subtracted. The black level BLK is defined by the black level setting unit 19 in accordance with a command from the microcomputer 8a, and a signal indicating the level is sent to the subtraction circuit 15.

Then, the output of the subtraction circuit 15 is sent to the multiplication circuit 16, where, as described above, different gain coefficients (KCy, KYe) are applied to the output signal levels of the light receiving elements corresponding to the respective color filters. , KG, KMg) (see FIG. 5). The value of each gain coefficient is set in the gain coefficient setting unit 20 according to a command from the microcomputer 8a, and then sent to the multiplication circuit 16 via the selector 21. , The gain coefficient for each of the filters of Cy, Ye, G, and Mg is selected, and the multiplication timing of the coefficient is defined. That is, the gain coefficient setting unit 20, the selector 2
1. The sequencer 23 is a gain coefficient setting means 24 for setting a predetermined gain coefficient for a plurality of types of optical filters.
Are controlled so that each gain coefficient and the output signal level of the light receiving element passed through each filter correspond to each other, and a multiplication process of both is performed. By this processing, the level of the imaging output that is not a black defect is adjusted to the same level, so that the sensitivity difference of the optical filter (the color filter in this case) is corrected, and the difference between the filters is absorbed.

The multiplying circuit 16 has a function of multiplying the output signal level of the light receiving element corresponding to each optical filter by a different gain coefficient. The output signal obtained from the light receiving element having no black defect is output. The correction means 25 is configured to perform level correction so that the level of the image data becomes the same specified level regardless of the type of the optical filter.

The output of the multiplying circuit 16 is the output of the subtracting circuit 1 in the subsequent stage.
The white level is defined by the white level setting unit 22 according to a command from the microcomputer 8a, and a signal indicating the level is transmitted to the subtraction circuit 17. Here, as described in FIG. 6, the prescribed level is defined as the white level, and the signal level after multiplication by the gain coefficient is subtracted from this level. Thus, the imaging output of the black defect is converted into a signal corresponding to the imaging output of the white defect.

The output of the subtraction circuit 17 is sent to the white defect detection circuit 10 via the selector 21 as described above, and the black defect is detected using the circuit. That is,
In this example, the determination means 26 determines a black defect based on information obtained as a difference between the above-mentioned specified level and the level of an output signal obtained from a light receiving element having a black defect.
The white defect detection circuit 10 is also used.

That is, when the signal shown in FIG. 6 is input to the white defect detection circuit 10, the defect level is detected, and the defect position information (address) of the light receiving element in the solid-state imaging device 3 is detected. You. Then, a sorting circuit is provided in this circuit, and the detection information is rearranged according to the level of the defect level (rearranged in descending order of the defect level). The same result as previously detected is obtained from a defect having a large influence.

The detected defect position information is stored in the nonvolatile memory 8b under the control of the microcomputer 8a.
And a series of black defect detection operations are completed.

Note that the black defect correction processing is the same as the white defect correction processing as is apparent from the fact that the existing white defect correction circuit is also used, and is read from the nonvolatile memory 8b under the control of the microcomputer 8a. The issued defect position information (defect address) is temporarily stored in the defect address memory 12, and then the correction signal generation circuit 1
The defect correction signal generated by the defect correction circuit 14 is
To perform a defect correction process.

The average value detection circuit 18 is a circuit for obtaining an average value of each signal from the analog / digital conversion circuit 5, that is, the level of the output signal obtained from the light receiving element for each optical filter. 23. Before detecting a black defect, it is necessary to determine a gain coefficient in advance. For this purpose, when plane light is incident on the solid-state imaging device 3, the average of the output signal level of a pixel having no defect is obtained. Average value detection circuit 18
Is calculated and sent to the microcomputer 8a. The microcomputer 8a calculates, as a gain coefficient, a value determined from a ratio obtained by dividing the above specified level by the average value (this is used as a value of the gain coefficient set in the gain coefficient setting unit 20). . In this circuit, the average value detection circuit itself constitutes the average value detection means, but the present invention is not limited to this, and various forms such as leaving the average value calculation processing to the microcomputer 8a are possible. Further, the value of the gain coefficient may be held in the memory of the microcomputer 8a or may be stored and held in the nonvolatile memory 8b in consideration of safety.

The procedure of the method for detecting a black defect according to the present invention is summarized as follows.

(1) A predetermined gain coefficient is set for each of a plurality of types of optical filters having a sensitivity difference.

(2) By multiplying the output signal level of the light receiving element corresponding to each optical filter by the above gain coefficient, level correction is performed so that the sensitivity characteristics of each optical filter become uniform.

(3) A defect level and its position are detected for a pixel having a black defect. That is, the level of the output signal obtained from the light receiving element having no black defect is the same specified level "LVL" regardless of the type of the optical filter, but is obtained from the light receiving element having the black defect (gain adjustment). Since the output signal level “Uj = Kj × Vj” (where j indicates one of “Cy, Ye, G, Mg”) indicates a level different from the above-mentioned specified level, The degree of the defect can be grasped by calculating the difference amount (LVL-Uj) by calculation.

In (3), after the output signals obtained from the respective light receiving elements having no black defect have the same specified level by multiplying by a gain coefficient, the output level is reduced from the specified level. What is necessary is just to subtract the signal level after multiplying the output signal level of the light receiving element by the gain coefficient of (1). At this time, the specified level is set to a white level, and the signal level after multiplying the output signal level of each light receiving element by a gain coefficient is subtracted from the level, and as described above, the detection indicating the size of the black defect is performed. Since the signal can be regarded as a signal corresponding to white defect detection and processed, the circuit configuration can be simplified.

In determining each gain coefficient, the level of an output signal obtained from the light receiving element for each optical filter, which is obtained when the solid-state imaging device 3 is irradiated with plane light, is detected. An average value is obtained, and a method of determining a gain coefficient from a ratio obtained by dividing a specified level by the average value is simple, and it is possible to obtain a gain coefficient according to an individual difference of an optical filter or a solid-state imaging device. preferable.

As described above, the defect level can be detected by performing the arithmetic processing of multiplying the gain coefficient corresponding to each optical filter by the level of the pixel output for each optical filter. The advantages shown are obtained.

Regarding the solid-state imaging device in which the sensitivity characteristics of each filter are different, the wavelength characteristic of the plane light incident upon detecting a defect does not matter. That is, since there is a difference between the detection signal level and the defect level depending on the wavelength characteristic, the detection accuracy does not become inaccurate when comparing with the reference level (threshold) (that is, the gain coefficient is not included in the defect level). Is multiplied.) In addition, it is not necessary to set a single reference level in black defect detection.

When the embodiment (ii) is adopted, the detecting means and the defect correcting means relating to the white defect can be used, which is advantageous for reducing the cost and the mounting area of the circuit by sharing the circuit.

[0067]

As is apparent from the above description, according to the first and eighth aspects of the present invention, the level of the output signal obtained from the light receiving element having no black defect depends on the type of the optical filter. The same specified level, and based on the fact that the level of the output signal obtained from the light receiving element having the black defect indicates a level different from the specified level,
Since the position and the degree of the black defect can be accurately detected, the black defect can be accurately detected for a solid-state imaging device using an optical filter having a sensitivity difference.

According to the second and ninth aspects of the invention,
A black defect detection signal can be obtained by simple arithmetic processing.

According to the third and tenth aspects of the present invention, the detection signal indicating the size of the black defect is subjected to level inversion processing and is regarded as a white defect detection signal, thereby utilizing the white defect detection circuit. As a result, the black defect can be detected, so that the circuit configuration can be simplified.

According to the seventh aspect of the present invention, it is possible to acquire a photographed image with extremely little deterioration by performing accurate black defect detection in the image pickup apparatus.

According to the inventions according to claims 4 to 6 and 11 to 13, the gain coefficient can be easily determined based on the calculation of the average value of the signal levels.

[Brief description of the drawings]

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

FIG. 2 is a block diagram illustrating a circuit configuration example of a black defect detection circuit.

FIG. 3 is an explanatory diagram of a black defect detection method together with FIGS. 4 to 6, and FIG. 3 is a graph showing an example of a signal output including a black defect.

FIG. 4 is a graph showing signal levels after subtracting a black level from each signal shown in FIG. 3;

FIG. 5 is a graph showing signal levels after multiplication by a gain coefficient.

FIG. 6 is a graph showing a signal level after subtracting each signal level after multiplying a gain coefficient by a white level as a specified level.

FIG. 7 is a graph for explaining a conventional black defect detection method.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Image pick-up device, 3 ... Solid-state image sensor, 18 ... Average value detection means, 24 ... Gain coefficient setting means, 25 ... Correction means, 26 ...
Judgment means

Claims (13)

[Claims] 1. A solid-state image sensor, in which a plurality of types of optical filters having different sensitivities due to wavelength characteristics of incident light are provided in respective light-receiving elements, output from the fixed image sensor when planar light is incident. A black defect detecting device for a solid-state imaging device for detecting a light receiving element having a black defect by monitoring a signal level to be applied, wherein a gain for setting a predetermined gain coefficient for the plurality of types of optical filters is provided. The coefficient setting means multiplies the output signal level of the light receiving element corresponding to each optical filter by a different gain coefficient, so that the level of the output signal obtained from the light receiving element having no black defect depends on the type of the optical filter. Correction means for correcting the level so as to be the same specified level, and the difference between the specified level and the level of the output signal obtained from the light receiving element having a black defect A black defect detecting device for a solid-state imaging device, comprising: a determination unit configured to determine a black defect from the image. 2. The black defect detecting device for a solid-state imaging device according to claim 1, wherein a signal level obtained by multiplying an output signal level of each light receiving element by a gain coefficient is subtracted from the same prescribed level. A black defect detection device for a solid-state imaging device, wherein a black defect detection signal is obtained by the above. 3. The black defect detecting device for a solid-state imaging device according to claim 1, wherein the same prescribed level is set to a white level, and the white level is used to determine an output signal level of each light receiving element. By subtracting the signal level after multiplying by the gain factor,
A black defect detection device for a solid-state image sensor, wherein a level inversion process is performed on a detection signal indicating the size of a black defect to obtain a detection signal. 4. The black defect detecting device for a solid-state image sensor according to claim 1, wherein when plane light is incident on the solid-state image sensor, an average of output signal levels obtained from light-receiving elements for each optical filter is obtained. A black defect detecting device for a solid-state imaging device, wherein an average value detecting means for obtaining a value is provided, and a gain coefficient setting means sets a value determined from a ratio obtained by dividing a specified level by the average value as a gain coefficient. . 5. The black defect detecting device for a solid-state imaging device according to claim 2, wherein when plane light is incident on the solid-state imaging device, an average of output signal levels obtained from the light-receiving devices for each optical filter is obtained. A black defect detecting device for a solid-state imaging device, wherein an average value detecting means for obtaining a value is provided, and a gain coefficient setting means sets a value determined from a ratio obtained by dividing a specified level by the average value as a gain coefficient. . 6. The black defect detecting device for a solid-state image sensor according to claim 3, wherein when plane light is incident on the solid-state image sensor, an average of output signal levels obtained from light-receiving elements for each optical filter is obtained. A black defect detecting device for a solid-state imaging device, wherein an average value detecting means for obtaining a value is provided, and a gain coefficient setting means sets a value determined from a ratio obtained by dividing a specified level by the average value as a gain coefficient. . 7. A solid-state imaging device in which a plurality of types of optical filters having different sensitivities due to wavelength characteristics of incident light are provided for each light-receiving element, and plane light is incident on the solid-state imaging device. In an imaging apparatus having a function of detecting a light receiving element having a black defect by monitoring a signal level output from the fixed imaging element, a gain coefficient predetermined for the plurality of types of optical filters is A gain coefficient setting means for setting, and multiplying the output signal level of the light receiving element corresponding to each optical filter by each different gain coefficient, the level of the output signal obtained from the light receiving element having no black defect is adjusted by the optical filter. Correcting means for correcting the level so as to be the same specified level irrespective of the type; and the specified level and the level of an output signal obtained from a light receiving element having a black defect. An imaging apparatus comprising: a determination unit configured to determine a black defect from a difference between the two. 8. A solid-state image sensor in which a plurality of types of optical filters having different sensitivities due to wavelength characteristics of incident light are provided in each light-receiving element. Detecting a light receiving element having a black defect by monitoring a signal level to be detected, wherein a predetermined gain coefficient is set for each of the plurality of types of optical filters. By multiplying the output signal level of the light receiving element corresponding to each optical filter by the above gain coefficient, the level is corrected so that the sensitivity characteristics of each optical filter become uniform, and the output signal obtained from the light receiving element having no black defect is obtained. Level is the same specified level regardless of the type of optical filter,
A black defect detection method for a solid-state imaging device, comprising: detecting occurrence of a black defect based on a level of an output signal obtained from a light receiving element having a black defect being different from the specified level. . 9. A black defect detecting method for a solid-state imaging device according to claim 8, wherein the levels of output signals obtained from the respective light receiving elements having no black defect are equalized by multiplication of gain coefficients so as to be the same specified level. After that, a black defect detection signal is obtained by subtracting the signal level obtained by multiplying the output signal level of each light receiving element by a gain coefficient from the specified level. Defect detection method. 10. The black defect detecting method for a solid-state imaging device according to claim 8, wherein the level of the output signal obtained from each light-receiving element having no black defect has the same white level by multiplying the level by a gain coefficient. Then, by subtracting the signal level obtained by multiplying the output signal level of each light receiving element by a gain coefficient from the white level, a level inversion process is performed on the detection signal indicating the size of the black defect. A black defect detection method for a solid-state imaging device, wherein the black defect detection signal is regarded as a white defect detection signal. 11. A black defect detecting method for a solid-state imaging device according to claim 8, wherein when plane light is incident on the solid-state imaging device, an average of output signal levels obtained from the light-receiving elements for each optical filter is obtained. A black defect detection method for a solid-state imaging device, comprising: obtaining a value; and determining a gain coefficient from a ratio obtained by dividing a specified level by the average value. 12. The black defect detecting method for a solid-state imaging device according to claim 9, wherein when plane light is incident on the solid-state imaging device, an average of output signal levels obtained from the light-receiving devices for each optical filter is obtained. A black defect detection method for a solid-state imaging device, comprising: obtaining a value; and determining a gain coefficient from a ratio obtained by dividing a specified level by the average value. 13. The black defect detection method for a solid-state imaging device according to claim 10, wherein when plane light is incident on the solid-state imaging device, an average of output signal levels obtained from the light-receiving elements for each optical filter is obtained. A black defect detection method for a solid-state imaging device, comprising: obtaining a value; and determining a gain coefficient from a ratio obtained by dividing a specified level by the average value.