JP2008141325A - Imaging device and defect correction method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an imaging device and a defect correction method which can correct void defects highly precisely without increasing storage means in comparison with conventional ones. <P>SOLUTION: A defect signal level calculation part 4 calculates offset components of all the flake defects on the basis of temperature of each pixel sensed by a sensor 11 when generating image data of an imaging device 1, a defect correction method 5 subtracts an offset component of a corresponding flake defect calculated by the defect signal level calculation part 4 from an output signal level of each flake defect in digital image data which the imaging device 1 has generated and an A/D conversion part 2 A/D has converted. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an imaging apparatus and a defect correction method for correcting digital image data including defective pixels.

A solid-state imaging device such as a CCD or CMOS may have a defective pixel that outputs an abnormal imaging signal due to a local crystal defect of a semiconductor or the like at a predetermined ratio or less. Due to this defective pixel, image quality degradation occurs in the image data generated by the imaging device.
Conventionally, various methods and circuit configurations for correcting image quality degradation caused by defective pixels by signal processing have been proposed. For example, Patent Document 1 includes a storage unit (memory or buffer) that stores position data (hereinafter referred to as defect data) of defective pixels, and a defect that interpolates data related to defective pixels with average value data of neighboring pixels or the like. Correction means are disclosed.

In particular, a defect called a white point defect among defective pixels has temperature dependency. The output characteristic of the white spot defect increases as the temperature increases, and the amount of increase has a linear relationship with the change in temperature.
For example, in the defective pixel correction method disclosed in Patent Document 1, the defect data stored in the storage means is measured at a specific temperature (for example, 50 ° C.), for example, data measured at the time of manufacturing the image sensor. Data based on data is used. That is, in the defective pixel correction method disclosed in Patent Document 1, particularly for white point defects, the temperature of the image sensor at the time of actual photographing (for example, 30 ° C.) is the temperature at the time of measuring the defect data stored in the storage means. If it is different from the above, there is a disadvantage that correct correction cannot be performed.

As a countermeasure against such a situation, there are techniques disclosed in Patent Documents 2, 3, and 4, for example.
Patent Document 2 discloses an imaging device that corrects a linear defect in a captured image when the temperature of the imaging element is higher than a predetermined threshold value.
Patent Document 3 discloses a pixel defect correction apparatus in which defect data corresponding to temperature and shutter speed is stored in a storage unit, and defect correction is performed using defect data corresponding to temperature and shutter speed at the time of shooting. It is disclosed.
In Patent Document 4, the fixed pattern noise (defect) of the image sensor for each temperature range is stored in the storage means, and this is used to subtract the fixed pattern noise from the output signal of the image sensor to remove the fixed pattern noise. An imaging apparatus that performs the above is disclosed.
Japanese Patent No. 3544304 JP 2006-108918 A JP 2000-101925 A Japanese Patent Laid-Open No. 01-147773

However, in the technique disclosed in Patent Document 2 described above, whether to perform correction is determined depending on whether the temperature of the image sensor is higher or lower than a predetermined threshold value. Since the same correction is performed at a temperature greatly exceeding the predetermined threshold and a temperature slightly exceeding the predetermined threshold, there is a disadvantage that the accuracy of the correction is low.
Further, in the techniques disclosed in Patent Documents 3 and 4, since the defect data for each temperature is stored in the storage unit in advance, the amount of data to be stored in the storage unit in advance increases, and the storage unit needs to be increased. There is a disadvantage of becoming.

  An object of the present invention is to provide an imaging apparatus and a defect correction method capable of correcting white point defects with high accuracy without increasing the storage means compared with the prior art in order to eliminate the disadvantages described above. To do.

  In order to achieve the above-described object, an imaging device of a first invention includes an imaging device that generates image data, a sensor that detects a temperature of the imaging device when the imaging device generates the image data, A defect detection unit that detects a white spot defect in the image data generated by the image sensor and generates defect data including a position of the detected white spot defect; and the image data of the image sensor detected by the sensor Based on the temperature at the time of generation, the white point defect detected by the defect detection unit using the first parameter indicating the relationship between the temperature of the image sensor and the output signal level of the white point defect in the image sensor. Output signal level of the white point defect from the image data generated by the image sensor based on the defect data generated by the defect detector A defect correction unit that corrects the white point defect by subtracting the offset value of the output signal level of the white point defect calculated by the defect signal level calculation unit from the output signal level of the white point defect Have.

  An image pickup apparatus according to a second aspect of the present invention generates an image data, and immediately after taking an image without incident light to generate a dark current noise image of only dark current noise, the darkness generated by the image pickup device Based on the current noise image, a temperature at which the temperature immediately after the image data generation of the image sensor is calculated using a second parameter indicating the relationship between the signal level of dark current noise and the temperature of the image sensor A calculation unit; a defect detection unit that detects a white spot defect in the image data generated by the imaging device; and generates defect data including a position of the detected white point defect; and the temperature calculation unit calculates the defect Based on the temperature immediately after the image data generation of the image sensor, a defect signal level calculation unit that calculates an offset value of the output signal level of the white spot defect detected by the defect detection unit, and the defect generated by the defect detection unit Day The white spot defect output signal level is obtained from the image data generated by the image sensor, and the white spot defect output calculated by the defect signal level calculation unit from the white spot defect output signal level. A defect correction unit that corrects the white point defect by subtracting the offset value of the signal level.

  A defect correction method according to a third aspect of the present invention is a defect correction method for an image pickup apparatus having an image sensor, wherein the image sensor generates image data, and the image sensor when the image data is generated. And detecting a white spot defect in the image data generated by the imaging device in the first process, and generating defect data including the position of the detected white spot defect. Based on the temperature at the time of image data generation of the image sensor detected in the third step and the second step, the temperature of the image sensor and the output signal level of the white point defect in the image sensor A fourth step of calculating an offset value of the output signal level of the white spot defect detected in the third step using the first parameter indicating the relationship; and the step generated in the third step Based on the defect data An output signal level of the white spot defect is acquired from the image data generated by the imaging device, and an offset of the output signal level of the white spot defect calculated in the fourth step from the output signal level of the white spot defect And a fifth step of correcting the white spot defect by subtracting the value.

  A defect correction method according to a fourth aspect of the present invention is a defect correction method for an image pickup apparatus having an image pickup device, wherein the image pickup device generates image data, and immediately after that, an image is taken without incident light and only dark current noise is detected. A sixth step of generating a dark current noise image, and a sixth step showing a relationship between a dark current noise signal level and the temperature of the image sensor based on the dark current noise image generated in the sixth step. A white point defect in the image data generated in the seventh step of calculating the temperature immediately after the image data generation time of the image sensor using the parameter of 2, and the sixth step; An eighth step of generating defect data including the position of the detected white spot defect, and the eighth step based on the temperature immediately after the generation of the image data of the image sensor calculated in the seventh step. White spot detected in The output of the white spot defect from the image data generated by the imaging device based on the defect data generated in the ninth step of calculating the offset value of the output signal level of the defect and the eighth step The signal level is acquired, and the white point defect correction is performed by subtracting the offset value of the output signal level of the white point defect calculated in the ninth step from the output signal level of the white point defect. 10 steps.

  According to the present invention, it is possible to provide an imaging apparatus and a defect correction method capable of correcting a white spot defect with high accuracy without increasing the storage means as compared with the prior art.

<First Embodiment>
Hereinafter, the imaging apparatus 100 according to the first embodiment will be described.
As illustrated in FIG. 1, the imaging apparatus 100 includes an imaging element 1, an A / D conversion unit 2, a defect detection unit 3, a defect signal level calculation unit 4, a defect correction unit 5, a signal processing unit 6, and a memory 7.
FIG. 1 is a block diagram illustrating a configuration example of the imaging apparatus 100.

The imaging element 1 is a light receiving element configured by a CCD (Charge Coupled Device), a CMOS (Complementary Metal Oxide Semiconductor), or the like, and converts the light collected by a lens (not shown in FIG. 1) into an analog electrical signal (image data). Convert and output.
Further, the image sensor 1 has a sensor 11.
The sensor 11 detects the temperature of each pixel of the image sensor 1.
The A / D conversion unit 2 converts analog image data generated by the imaging device 1 into digital image data and outputs the digital image data.

The defect detection unit 3 detects all white spot defects in the digital image data output from the A / D conversion unit 2 and stores the positions in a memory 7 described later as defect data.
The detection method of the white spot defect of the defect detection unit 3 is not limited in the present invention. Conventional techniques can be used.

The defect signal level calculation unit 4 calculates the value of the signal level output by the white spot defect detected by the defect detection unit 3 based on the temperature at the time of image data generation of the image sensor 1 detected by the sensor 11.
Hereinafter, the defect signal level calculation process of the defect signal level calculation unit 4 will be described.

  The white spot defect is a defect in which a dark current is generated in a semiconductor constituting the image sensor 1 and a signal output is larger than that of a pixel that is not a defect. Since the dark current increases as the operating temperature of the image sensor increases, the signal output at the white spot defect also increases as the temperature of the image sensor increases.

FIG. 2 shows a specific example of the output increase due to the temperature of the white spot defect.
FIG. 2 is a diagram illustrating the relationship between the amount of light incident on the image sensor (unit is not limited), the output level (unit mV) output by the white spot defect, and temperature in a specific white spot defect.
In FIG. 2, the solid line passing through the origin indicates the relationship between the output signal level and the amount of light when the pixel is not a white spot defect, and the broken line is the temperature of the white spot defect (temperature of the image sensor) is 25 ° C. The relationship between the output signal level from the white spot defect and the amount of light, and the long chain line represents the relationship between the output signal level from the white spot defect and the amount of light when the temperature of the white spot defect is 50 ° C., respectively. Show.

As shown in FIG. 2, it can be seen that the higher the temperature of the white spot defect, the higher the output signal level for the same amount of light.
For the same amount of light, the difference (5 mV) between the output signal level when the pixel is not a white point defect and the output signal level when the white point defect is 50 ° C. is that the pixel is not a white point defect. This is twice the difference (2.5 mV) between the output signal level and the output signal level when the white spot defect is 25 ° C. Thus, the difference between the output signal level of the white spot defect and the output signal level when the pixel is not a white spot defect (hereinafter referred to as an offset component) is empirically proportional to the temperature (° C.). I know.

  FIG. 3 shows an example of the relationship between the signal level output by the white spot defect and the temperature. Since the difference between the signal level output by the white spot defect and the output signal level of the image sensor without the defect is proportional to the temperature (° C.), the relationship between the signal level output by the white spot defect and the temperature is shown in FIG. As shown in FIG. Therefore, by measuring the output level of the white spot defect inherent to the image sensor 1 at at least two different temperatures when the imaging device 100 is manufactured, for example, the signal level output by the white spot defect as shown in FIG. A parameter (slope and intercept: hereinafter referred to as an output / temperature parameter, which corresponds to the first parameter of the present invention) for constructing a relational expression between temperature and temperature can be calculated in advance, and a defect signal level calculation unit 4, using the output / temperature parameter, the offset component of the white defect can be obtained based on the temperature of the imaging device 1 detected by the sensor 11 when the imaging device 100 is used.

  As described above, the defect signal level calculation unit 4 detects the temperature value at the time of image data generation of the image sensor 1 detected by the sensor 11, the output / temperature parameter stored in the memory 7 to be described later, and the defect detection. Based on the defect data detected by the unit 3, offset components of all white point defects detected by the defect detection unit 3 are calculated.

The defect correction unit 5 corrects the output level of each white point defect using the offset components of all white point defects calculated by the defect signal level calculation unit 4.
As described above, the offset component is the difference between the output signal level of the white spot defect and the output signal level when the pixel is not a white spot defect. By subtracting the offset component from the output signal level of the white spot defect on the image data 2 subjected to A / D conversion, the output signal level when the pixel is not a white defect can be calculated. That is, white defects can be corrected.
In other words, the defect correction unit 5 calculates the defect signal from the output signal levels of all white defects detected by the defect detection unit 3 in the digital image data generated by the image sensor 1 and A / D converted by the A / D conversion unit 2. Each white defect is corrected by subtracting the offset component of the white point defect calculated by the level calculation unit 4.

The signal processing unit 6 applies luminance signal / expression difference signal generation processing, automatic exposure processing, automatic focus processing, color signal processing (white balance adjustment, γ processing, etc.) to the digital image data that has been subjected to defect correction by the defect correction unit 5. Digital image signal processing such as luminance signal processing (low frequency partial extraction, etc.) is performed and output.
The memory 7 is a storage device that stores defect data detected by the defect detection unit 3. The memory 7 stores the output / temperature parameters of the image sensor 1 in advance when the image pickup apparatus 100 is manufactured.

Next, an operation example at the time of white defect correction of the imaging apparatus 100 will be described.
FIG. 4 is a flowchart illustrating an operation example of the imaging apparatus 100.
Step ST1:
The image sensor 1 generates analog image data.
Step ST2:
The sensor 11 detects the temperature of each pixel of the image sensor 1 when image data is generated.

Step ST3:
The A / D converter 2 performs A / D conversion on the analog image data generated by the image sensor 1 in step ST1, and outputs digital image data.
Step ST4:
The defect detection unit 3 determines whether all the pixels of the digital image data output from the A / D conversion unit 2 in step ST3 are white defects, and detects all white defects. The defect detection unit 3 stores the detected position of the white defect in the memory 7 as defect data.

Step ST5:
The defect signal level calculation unit 4 calculates the temperature of each white defect detected by the sensor 11 and the output / temperature parameter stored in advance in the memory 7 for all white defects detected by the defect detection unit 3 in step ST4. Based on the above, the offset component of each white defect is calculated.
Step ST6:
The defect correction unit 5 acquires the output signal levels of all white defects from the digital image data output by the A / D conversion unit 2 in step ST3 based on the defect data output by the defect detection unit 3 in step ST4. The defect correction is performed by subtracting the offset component of the corresponding white defect calculated by the defect signal level calculation unit 4 in step ST5 from the output signal level of each white defect, and calculating the normal output signal level of the pixel. .
Step ST7:
The signal processing unit 6 performs various kinds of signal processing on the digital image data in which the defect correction unit 5 has corrected all the white defects in step ST6, and outputs the digital image data. Here, various signal processing performed by the signal processing unit 6 is not limited in the present invention.

  As described above, in the imaging apparatus 100 of this embodiment, the difference (offset component) between the output signal level of the white spot defect and the output signal level when the pixel is not a white spot defect is the temperature (° C.). The defect signal level calculation unit 4 calculates offset components of all white spot defects based on the temperature of each pixel detected by the sensor 11 when the image data of the image sensor 1 is generated. The corresponding white point defect calculated by the defect signal level calculation unit 4 from the output signal level of each white point defect in the digital image data generated by the image sensor 1 by the unit 5 and A / D converted by the A / D conversion unit 2 By subtracting the offset component, white point defects can be corrected.

Thereby, since the imaging device 100 of this embodiment performs white defect correction according to the temperature of the imaging device at the time of image data generation, it can perform highly accurate defect correction.
Further, only the output / temperature parameter needs to be stored in advance in the memory 7 at the time of manufacturing the imaging apparatus 100, and the output / temperature parameter is composed of only two pieces of information of the slope and the intercept. The amount of information to be stored in the memory 7 in advance is small, and it is possible to reduce the components of the entire imaging apparatus 100 and the manufacturing process.

<Second Embodiment>
Hereinafter, the imaging apparatus 101 of the second embodiment will be described.
FIG. 5 is a block diagram illustrating a configuration example of the imaging apparatus 101 according to the second embodiment.
As shown in FIG. 5, the imaging device 101 includes an imaging device 1, an A / D conversion unit 2, a defect detection unit 3, a defect signal level calculation unit 4, a defect correction unit 5, a signal processing unit 6, a memory 7, and a temperature calculation. Part 8.
That is, the imaging apparatus 101 of the present embodiment has the same configuration as the imaging apparatus 100 of the first embodiment except for the sensor 11 and the temperature calculation unit 8.
The imaging apparatus 101 of the present embodiment is different from the imaging apparatus 100 of the first embodiment in that the temperature calculation unit 8 estimates the temperature of each pixel of the imaging element 1 when generating image data instead of the sensor 11. .

The imaging element 1 is a light receiving element configured by a CCD, a CMOS, or the like, and converts the light collected by a lens (not shown in FIG. 5) into an analog electric signal (image data) and outputs it.
In the present embodiment, the image sensor 1 does not have the sensor 11 that detects the temperature of each pixel.
In addition, immediately after analog image data is captured, the image sensor 1 captures the light-shielding space with the same exposure time, and generates an image with only dark current noise. This dark current noise image is image data used by a temperature calculation unit 8 to be described later for temperature calculation.
The A / D converter 2 converts the analog image data (and dark current noise image) generated by the imaging device 1 into digital image data and outputs the digital image data.

The defect detection unit 3 detects all white spot defects in the digital image data output from the A / D conversion unit 2 and stores the positions in the memory 7 as defect data.
The detection method of the white spot defect of the defect detection unit 3 is not limited in the present invention. Conventional techniques can be used.

  The defect signal level calculation unit 4 is a temperature value at the time of image data generation of the image sensor 1 detected by a temperature calculation unit 8 described later, an output / temperature parameter stored in advance in a memory 7 described later, and the defect detection unit 3. Based on the defect data detected by, the offset components of all white point defects detected by the defect detection unit 3 are calculated by a method similar to the method described in the first embodiment.

  The defect correction unit 5 calculates the defect signal level from the output signal levels of all white defects detected by the defect detection unit 3 in the digital image data generated by the image sensor 1 and A / D converted by the A / D conversion unit 2. Each white defect is corrected by subtracting the offset component of the white point defect calculated by the unit 4.

The signal processing unit 6 applies luminance signal / expression difference signal generation processing, automatic exposure processing, automatic focus processing, color signal processing (white balance adjustment, γ processing, etc.) to the digital image data that has been subjected to defect correction by the defect correction unit 5. Digital image signal processing such as luminance signal processing (low frequency partial extraction, etc.) is performed and output.
The memory 7 is a storage device that stores defect data detected by the defect detection unit 3. The memory 7 stores in advance a temperature calculation parameter (corresponding to a second parameter of the present invention) described later and the output / temperature parameter described in the first embodiment.

The temperature calculation unit 8 calculates the temperature at the time of image data generation of the image sensor 1 based on the dark current noise image generated immediately after the image sensor 1 captures the image data.
Since the dark current noise image is an image generated in a state where the image sensor 1 does not sense incident light, the signal level should be zero in all pixels.
However, a solid-state imaging device such as a CCD or CMOS generally has a dark output (dark voltage) characteristic in which an output voltage is generated even in a state where incident light is shielded, and accordingly, a minute current called a dark current is generated. For this reason, only the signal (dark current noise) resulting from the dark current is captured in the dark current noise image.
Here, it has been empirically found that the dark current has a temperature dependency of approximately twice as large as a temperature change (rise) of the image sensor of about 8 ° C. That is, there is an exponential relationship between the dark current and the temperature rise of the image sensor.
In addition, since the signal level of dark current noise reflected in the dark current noise image is proportional to the dark current, the signal level of dark current noise in the dark current noise image is increased by a temperature rise of the image sensor of about 8 ° C. Also, it can be seen that there is an exponential relationship between the temperature rise of the image sensor and the dark current noise signal level in the dark current noise image.

Therefore, for example, at the time of manufacturing the image pickup apparatus 101, a dark current noise image of the image pickup device 1 is taken at a predetermined temperature, and the relationship indicating the relationship between the dark current noise signal level in the dark current noise image and the temperature. It is possible to derive an expression. Since the relational expression is known to be an exponential function for the above-described reason, the temperature calculation unit 8 can capture the image by storing the parameter of the relational expression (the temperature calculation parameter described above) in the memory 7. Based on the dark current noise image taken immediately after the image data is generated by the element 1, the temperature of the image sensor 1 can be calculated by a relational expression including the temperature calculation parameter.
As described above, the temperature calculation unit 8 uses the temperature calculation parameter stored in advance in the memory 7 based on the dark current noise image captured immediately after the image sensor 1 generates the image data. The temperature at the time of image data shooting (immediately after) is calculated.

Hereinafter, an operation example of the imaging apparatus 101 of the present embodiment will be described.
FIG. 6 is a flowchart for explaining an operation example of the imaging apparatus 101 according to the second embodiment.
Step ST11:
The image sensor 1 generates analog image data. In addition, immediately after analog image data is captured, the image sensor 1 captures the light-shielding space with the same exposure time, and generates an image with only dark current noise.
Step ST12:
The A / D converter 2 performs A / D conversion on the analog image data generated by the image sensor 1 in step ST11 and outputs digital image data.

Step ST13:
The defect detection unit 3 determines whether or not all pixels of the digital image data output from the A / D conversion unit 2 are white defects, and detects all white defects. The defect detection unit 3 stores the detected position of the white defect in the memory 7 as defect data.
Step ST14:
The temperature calculation unit 8 uses a temperature calculation parameter stored in advance in the memory 7 on the basis of a dark current noise image captured immediately after the image sensor 1 generates image data. ) Is calculated.

Step ST15:
The defect signal level calculation unit 4 calculates the entire image data based on the temperature of the image sensor 1 immediately after the image data generation calculated by the temperature calculation unit 8 in step ST14 and the output / temperature parameter stored in the memory 7 in advance. The offset component of the white defect is calculated.
Step ST16:
The defect correction unit 5 acquires the output signal levels of all white defects from the digital image data output by the A / D conversion unit 2 in step ST12 based on the defect data output by the defect detection unit 3 in step ST3. Defect correction is performed by subtracting the offset component of the output signal level of the white defect calculated by the defect signal level calculation unit 4 in step ST15 from the output signal level of each white defect, and calculating the normal output signal level of the pixel. Do.

Step ST17:
The signal processing unit 6 performs various types of signal processing on the digital image data that has been subjected to defect correction of all white defects by the defect correction unit 5 in step ST16, and outputs the digital image data. Here, various signal processing performed by the signal processing unit 6 is not limited in the present invention.

  As described above, in the imaging apparatus 101 of the present embodiment, imaging is performed using the temperature calculation parameter stored in advance in the memory 7 based on the dark current noise image captured by the imaging device 1 immediately after the image data is generated. Since the temperature calculation unit 8 calculates the temperature when the image data of the element 1 is captured (immediately after), the number of components of the imaging device 101 is reduced by the amount that the sensor 11 is not required compared to the imaging device 100 of the first embodiment. Therefore, the number of processes at the time of manufacturing is reduced, and the manufacturing cost is reduced.

The present invention is not limited to the embodiment described above.
That is, when implementing the present invention, various modifications, combinations, sub-combinations, and alternatives may be made to the components of the above-described embodiments within the technical scope of the present invention or an equivalent scope thereof.

  For example, in the imaging devices 100 and 101 according to the above-described embodiments, the defect signal level calculation unit 4 calculates the offset component of the output signal level of the white defect based on the temperature of the imaging element 1. Since it is known that the offset component of the output signal level depends not only on the temperature of the image sensor but also on the exposure time, this fact is used to calculate the offset between the exposure time and the offset component of the output signal level of the white defect. By deriving the relational expression in advance, the defect signal level calculation unit 4 may calculate the offset component of the output signal level of the white defect using the exposure time when generating the image data together with the temperature. In this case, a more accurate offset component of the output signal level of the white defect can be calculated.

  In the imaging devices 100 and 101 according to the above-described embodiments, the output signal levels of all white defects are derived from the digital image data output from the A / D conversion unit 2 based on the defect data output by the defect detection unit 3. The defect correction unit obtains and calculates the normal output signal level of the pixel by subtracting the offset component of the output signal level of the white defect calculated by the defect signal level calculation unit 4 from the output signal level of each white defect In FIG. 5, defect correction was performed, but the present invention is not limited to this. For example, when the temperature difference between the temperature of the image sensor and the surroundings becomes large, such as when shooting at low temperatures, the offset component of the output signal level of the white defect becomes large, and the reliability of the offset component Will fall. Therefore, in such a case, a threshold value of a predetermined offset component is set in advance, and when the calculated offset component is smaller than the threshold value, the defect correction unit 5 is similar to the above-described embodiment. Performs correction by subtracting the offset value from the white defect output signal level of the digital image data, and when the calculated offset component is larger than the threshold value, the defect correction unit 5 detects the white defect in the digital image data. A configuration may be adopted in which white defect correction is performed using pixel values existing around. The white defect correction using the pixel values existing around the white defect is, for example, a method of averaging the peripheral pixel values to obtain the pixel value of the white defect, and a conventional technique can be used.

  Note that the defect detection unit 3, the defect signal level calculation unit 4, the defect correction unit 5, and the temperature calculation unit 8 in the imaging devices 100 and 101 according to the above-described embodiments may be configured in hardware, or may be software-like. It may be configured.

FIG. 1 is a block diagram illustrating a configuration example of the imaging apparatus 100 according to the first embodiment. FIG. 2 is a diagram showing a specific example of the output increase due to the temperature of the white spot defect. FIG. 3 is a diagram illustrating an example of the relationship between the signal level output by the white spot defect and the temperature. FIG. 4 is a flowchart illustrating an operation example of the imaging apparatus 100. FIG. 5 is a block diagram illustrating a configuration example of the imaging apparatus 101 according to the second embodiment. FIG. 6 is a flowchart for explaining an operation example of the imaging apparatus 101 according to the second embodiment.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 100,101 ... Imaging device, 1 ... Imaging element, 11 ... Sensor, 2 ... A / D conversion part, 3 ... Defect detection part, 4 ... Defect signal level calculation part, 5 ... Defect correction part, 6 ... Signal processing part, 7: Memory, 8 ... Temperature calculation unit

Claims (4)

An image sensor for generating image data;
A sensor that detects the temperature of the image sensor when the image sensor generates the image data;
A defect detection unit that detects a white spot defect in the image data generated by the image sensor and generates defect data including a position of the detected white spot defect;
Based on the temperature of the image sensor detected by the sensor when the image data is generated, the first parameter indicating the relationship between the temperature of the image sensor and the output signal level of the white point defect in the image sensor is used. A defect signal level calculation unit that calculates an offset value of the output signal level of the white spot defect detected by the defect detection unit;
Based on the defect data generated by the defect detection unit, the output signal level of the white spot defect is acquired from the image data generated by the imaging device, and the defect signal level is calculated from the output signal level of the white spot defect. A defect correction unit that corrects the white point defect by subtracting the offset value of the output signal level of the white point defect calculated by the unit;
An imaging apparatus having An image sensor that generates image data, and immediately after shooting in the absence of incident light to generate a dark current noise image of only dark current noise,
Based on the dark current noise image generated by the image sensor, the second parameter indicating the relationship between the signal level of dark current noise and the temperature of the image sensor is used to generate the image data of the image sensor. A temperature calculation unit for calculating the temperature immediately after the hour;
A defect detection unit that detects a white spot defect in the image data generated by the image sensor and generates defect data including a position of the detected white spot defect;
A defect signal level calculation unit that calculates an offset value of the output signal level of the white point defect detected by the defect detection unit based on the temperature immediately after the image data generation of the image sensor calculated by the temperature calculation unit;
Based on the defect data generated by the defect detection unit, the output signal level of the white spot defect is acquired from the image data generated by the imaging device, and the defect signal level is calculated from the output signal level of the white spot defect. A defect correction unit that corrects the white point defect by subtracting the offset value of the output signal level of the white point defect calculated by the unit;
An imaging apparatus having A defect correction method for an imaging apparatus having an imaging element,
A first step in which the image sensor generates image data;
A second step of detecting the temperature of the image sensor when the image data is generated;
A third step of detecting a white spot defect in the image data generated by the imaging element in the first step and generating defect data including a position of the detected white spot defect;
A first relationship between the temperature of the image sensor detected in the second step and the output signal level of the white point defect in the image sensor based on the temperature at which the image data is generated of the image sensor. A fourth step of calculating an offset value of the output signal level of the white spot defect detected in the third step using a parameter;
Based on the defect data generated in the third step, an output signal level of the white spot defect is obtained from the image data generated by the imaging device, and the fourth output signal level of the white spot defect is obtained. A fifth step of correcting the white spot defect by subtracting the offset value of the output signal level of the white spot defect calculated in the step;
A defect correction method comprising: A defect correction method for an imaging apparatus having an imaging element,
A sixth step in which the imaging element generates image data, and immediately after shooting in the absence of incident light, a dark current noise image only of dark current noise is generated;
Based on the dark current noise image generated in the sixth step, the second parameter indicating the relationship between the dark current noise signal level and the temperature of the image sensor, and A seventh step of calculating a temperature immediately after image data generation;
An eighth step of detecting a white spot defect in the image data generated in the sixth step and generating defect data including a position of the detected white spot defect;
Ninth step of calculating an offset value of the output signal level of the white spot defect detected in the eighth step based on the temperature immediately after the generation of the image data of the image sensor calculated in the seventh step. When,
Based on the defect data generated in the eighth step, an output signal level of the white point defect is obtained from the image data generated by the imaging device, and the output signal level of the white point defect is A tenth step of correcting the white point defect by subtracting the offset value of the output signal level of the white point defect calculated in step 9;
A defect correction method comprising:

Images