JP2013207611A - Imaging device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an imaging device which can accurately detect a defective pixel.SOLUTION: An imaging device comprises: an image sensor which takes an image by generating pixel signals corresponding to light; and a detection unit which detects a defective pixel in the image sensor on the basis of a first image taken by the image sensor and a second image taken by the image sensor under the photographing conditions same as the first image.

Description

  The present invention relates to an imaging apparatus.

  2. Description of the Related Art In recent years, imaging devices including imaging elements such as CCD (Charge Coupled Device) image sensors and CMOS (Complementary Metal Oxide Semiconductor) image sensors have been widely used. In an imaging device such as a CCD image sensor or a CMOS image sensor provided in this imaging device, a defective pixel may occur later due to aging or radiation (for example, cosmic rays). A technique for determining such a late defective pixel in an imaging apparatus is known (see, for example, Patent Document 1).

JP 2010-028487 A

However, in the technique as described above, for example, a case where an output value of a pixel determined with respect to an average value of peripheral pixels is higher than a predetermined threshold is determined as a defective pixel. In this case, if there is a defective pixel having a high output value in the peripheral pixels, the average value of the peripheral pixels becomes high, so that there is a possibility that the defective pixel cannot be accurately determined.
As described above, the imaging apparatus using the above-described technique has a problem in that defective pixels may not be detected accurately.

  The present invention has been made to solve the above problems, and an object thereof is to provide an imaging apparatus capable of accurately detecting defective pixels.

  In order to solve the above problem, an embodiment of the present invention provides an image sensor that captures an image by generating a pixel signal corresponding to light, a first image captured by the image sensor, and the first image An image pickup apparatus comprising: a detection unit that detects a defective pixel included in the image pickup device based on a second image picked up by the image pickup device under an image pickup condition equal to that of the first image.

  According to the present invention, the imaging apparatus can accurately detect defective pixels.

It is a block diagram which shows the imaging device by 1st Embodiment. 3 is a flowchart illustrating a defective pixel detection operation of the imaging apparatus according to the first embodiment. It is a flowchart which shows the detection process of the defective pixel in 1st Embodiment. It is a flowchart which shows the detection process of the defective pixel in 2nd Embodiment. It is a block diagram which shows the imaging device by 3rd Embodiment. 10 is a flowchart illustrating a defective pixel detection operation of the imaging apparatus according to the third embodiment. It is a block diagram which shows the imaging device by 4th Embodiment. It is a flowchart which shows the detection process of the defective pixel in 4th Embodiment. It is a flowchart which shows the detection process of the defective pixel in 5th Embodiment.

Hereinafter, an imaging apparatus according to an embodiment of the present invention will be described with reference to the drawings.
[First Embodiment]
FIG. 1 is a block diagram illustrating an imaging apparatus 1 according to the present embodiment.
In this figure, the imaging apparatus 1 includes an imaging unit 10, a buffer memory unit 30, an image processing unit 40, a display unit 50, a storage unit 60, a communication unit 70, an operation unit 80, and a control unit 90.

The imaging unit 10 includes an optical system 11 including a plurality of lenses, an imaging element 12, and an A / D (analog / digital) conversion unit 13. The imaging unit 10 is controlled by the control unit 90 based on set imaging conditions (for example, aperture value, exposure value, exposure time, etc.). The imaging unit 10 forms an optical image via the optical system 11 on the imaging element 12 and generates image data based on the optical image converted by the A / D conversion unit 13. That is, the imaging unit 10 captures an image of an optical image via the optical system 11.
The optical system 11 described above may be attached to and integrated with the imaging apparatus 1 or may be attached to the imaging apparatus 1 so as to be detachable.

For example, the image sensor 12 converts an optical image formed on a light receiving surface (not shown) into an electric signal (voltage signal) and supplies the electric signal to the A / D converter 13. The light receiving surface of the image pickup device 12 is composed of a plurality of image sensors (not shown) arranged in a grid such as a CCD (Charge Coupled Device) image sensor, for example, and each image sensor has each image to be captured. The imaged optical image corresponding to the pixel is converted into a voltage value. That is, the image sensor 12 captures an image by generating a pixel signal corresponding to light incident on the image sensor 12 via the optical system 11.
Note that the imaging element 12 has a defective pixel that outputs a high voltage signal regardless of light. This defective pixel includes an initial defective pixel that has already occurred in the manufacturing stage and a later defective pixel that occurs due to aging or cosmic rays. Further, the late defective pixels include blinking defective pixels (variable defective pixels) in which a case where a high voltage signal is output regardless of light and a case where a high voltage signal is not output are randomly generated. That is, a blinking defective pixel (variable defective pixel) is a defective pixel that occurs discontinuously in time. The imaging device 1 detects this subsequent defective pixel and blinking defective pixel. The detection process of defective pixels by the imaging device 1 in the present embodiment will be described later in detail.

  The A / D converter 13 performs analog-to-digital conversion on the voltage value (pixel signal) converted by the image sensor 12 and outputs image data formed by the converted digital signal (pixel data).

The buffer memory unit 30 temporarily stores image data captured by the imaging unit 10 and the like.
The image processing unit 40 performs image processing on the image data stored in the buffer memory unit 30 based on the image processing conditions stored in the storage unit 60. The image data stored in the buffer memory unit 30 here is image data (input image) input to the image processing unit 40. For example, captured image data, through image data, or a storage medium This is captured image data read from 200.

  The display unit 50 is, for example, a liquid crystal display, and displays image data captured by the imaging unit 10, an operation screen, and the like. The display unit 50 may be a display unit in the finder.

The storage unit 60 stores various information used for processing of the control unit 90, imaging conditions by the imaging unit 10, image processing conditions, and the like.
The storage unit 60 includes an image storage unit 61, a defect storage unit 62, and a blinking defect storage unit 63.

The image storage unit 61 stores image data (first image) captured in advance by the image sensor 12 under a predetermined imaging condition used when detecting a defective pixel described later. The image storage unit 61 stores two pieces of image data, initial captured image data (initially stored image data) and previous captured image data.
The initial picked-up image data is an image picked up by the image pickup element 12 under a predetermined image pickup condition set in advance in order to detect a defective pixel with high accuracy in an inspection process when the image pickup apparatus 1 is manufactured. The initial captured image data is, for example, an image captured in a state where the image sensor 12 is shielded from light. Here, the state where the image sensor 12 is shielded is a state where light incident on the optical system 11 is shielded by a shutter (not shown) included in the optical system 11 and light is not incident on the image sensor 12.
Further, the previous captured image data is obtained by comparing the image captured by the image sensor 12 under the same imaging condition as the above-described initial captured image data when detecting a defective pixel described later (first image). ) As image data stored in the image storage unit 61.

The defect storage unit 62 stores, for example, address information (position information) of defective pixels as defective pixel information. That is, the defect storage unit 62 stores position information corresponding to the defective pixel. Here, the position information corresponding to the defective pixel is information indicating the pixel position corresponding to the detected defective pixel. The defective pixel information stored in the defect storage unit 62 includes information corresponding to the initial defective pixel detected in the inspection process when manufacturing the imaging device 1 and later generations caused by aging or cosmic rays. And information corresponding to the defective pixel. The information corresponding to the later defective pixel is defective pixel information detected in a process for detecting a defective pixel, which will be described later.
The blinking defect storage unit 63 (variable defect storage unit) stores, for example, address information (position information) of the above-described blinking defect pixel (variable defect pixel). That is, the blinking defect storage unit 63 stores position information corresponding to blinking defective pixels (variable defective pixels). Here, the position information corresponding to the blinking defective pixel (variable defective pixel) is information indicating the pixel position corresponding to the detected blinking defective pixel (variable defective pixel). This blinking defective pixel is included in a later defective pixel, and is detected in a process of detecting a defective pixel described later.

The communication unit 70 is connected to a removable storage medium 200 such as a card memory, and performs writing, reading, or erasing of image data on the storage medium 200.
The storage medium 200 is a storage unit that is detachably connected to the imaging apparatus 1 and stores, for example, image data captured by the imaging unit 10.

  The operation unit 80 includes, for example, a power switch, a shutter button, a cross key, a confirmation button, a delete button, and other operation keys. The operation unit 80 is operated by a user to receive a user's operation input and perform control. To the unit 90.

  The bus 300 is connected to the imaging unit 10, the buffer memory unit 30, the image processing unit 40, the display unit 50, the storage unit 60, the communication unit 70, the operation unit 80, and the control unit 90. The output image data and control signals are transferred.

The control unit 90 includes, for example, a CPU (Central processing unit) and the like, and controls each component included in the imaging apparatus 1. For example, when receiving an imaging instruction via the operation unit 80, the control unit 90 uses the image data obtained via the imaging element 12 and the A / D conversion unit 13 as a captured image as the storage medium 200. Remember me. For example, the control unit 90 executes a process of detecting a defective pixel included in the image sensor 12 and causes the storage unit 60 to store address information of the detected defective pixel. Details of the function of the control unit 90 will be described later.
In addition, the control unit 90 includes a defect detection unit 20 and a defect correction unit 93. Further, the defect detection unit 20 includes a calculation unit 91 and a determination unit 92.

The defect detection unit 20 (detection unit) executes processing for detecting defective pixels included in the image sensor 12. The defect detection unit 20 causes the image sensor 12 to capture images under the same imaging conditions as the first image captured in advance by the image sensor 12 and the first image. The defect detection unit 20 is based on a comparison result between the first image captured in advance by the image sensor 12 and the second image captured by the image sensor 12 under the same imaging conditions as the first image. Detect defective pixels 12.
Here, the first image is initial captured image data or previous captured image data stored in the image storage unit 61. In the present embodiment, for example, in the detection process of the first defective pixel after manufacturing, the detection process is performed using the initial captured image data as the first image, and the previous captured image is detected in the second and subsequent defective pixel detection processes. The detection process is performed using the data as the first image. Note that the first image and the second image are, for example, images captured with the image sensor 12 shielded from light.

Further, the defect detection unit 20 is based on the calculation result of the first pixel signal in the first image and the second pixel signal in the second image corresponding to the pixel position of the first pixel signal. The first image and the second image are compared, and defective pixels are detected based on the comparison result. Here, the “pixel signal” is a signal indicating a pixel value, and may be an analog signal indicating a pixel value according to a voltage level or a digital signal indicating a coded pixel value. In this embodiment, as an example, pixel data that is a digital signal indicating a pixel value obtained by coding a “pixel signal” will be described.
Further, the defect detection unit 20 causes the defect storage unit 62 to store address information (position information) corresponding to the detected defective pixel.

  In addition, in the process of detecting a defective pixel, the defect detection unit 20 performs a process of detecting the blinking defective pixel by causing the above-described imaging element 12 to capture the second image a plurality of times. For example, the defect detection unit 20 causes the image sensor 12 to capture the second image a plurality of times under the same imaging conditions as the first image described above. The defect detection unit 20 uses the second image captured one time ago as the first image, and compares the first image with the plurality of captured second images. Flashing (variable) defective pixels are detected. The defect detection unit 20 stores address information (position information) corresponding to the detected blinking defective pixel in the blinking defect storage unit 63.

  The calculation unit 91 calculates the difference between the first image and the second image. In other words, the calculation unit 91 includes the first pixel data (first pixel signal) in the first image and the second pixel data (second pixel) in the second image corresponding to the pixel position of the first pixel data. The pixel signal is calculated. The calculation unit 91 supplies the calculated calculation result (difference value) to the determination unit 92.

The determination unit 92 compares the first image and the second image for each pixel position based on the difference calculated by the calculation unit 91, and the pixel corresponding to the compared pixel position based on the comparison result. Is a defective pixel. Further, when the determination unit 92 determines that the compared pixel position is a defective pixel, the determination unit 92 causes the defect storage unit 62 to store address information (position information) corresponding to the defective pixel.
Further, the determination unit 92 compares the second image captured one time before and the second image captured this time for each pixel position based on the difference calculated by the calculation unit 91. Based on the comparison result, the determination unit 92 determines whether or not the pixel corresponding to the compared pixel position is a blinking (variable) defective pixel among the defective pixels. When the determination unit 92 determines that the compared pixel position is a blinking defective pixel, the determination unit 92 stores address information (position information) corresponding to the blinking defective pixel in the blinking defect storage unit 63.

  The defect correction unit 93 (first correction unit) is, for example, image data obtained by imaging an imaging target such as a subject by the imaging element 12 based on address information corresponding to a defective pixel stored in the defect storage unit 62. (Third image) is corrected. That is, the defect correction unit 93 corrects the image (third image) captured by the image sensor 12 based on the position information corresponding to the defective pixel detected by the defect detection unit 20. For example, the defect correction unit 93 performs a correction process for interpolating the pixel value at the defective pixel position based on the pixel values in the vicinity (peripheral) of the defective pixel. Note that the defect correction unit 93 may perform a correction process for the blinking defective pixel based on the address information corresponding to the blinking defective pixel stored in the blinking defect storage unit 63.

Next, the operation of the imaging device 1 in the present embodiment will be described.
FIG. 2 is a flowchart illustrating the defective pixel detection operation of the imaging apparatus 1 according to the present embodiment.
In this figure, the imaging apparatus 1 is first shifted from the imaging operation mode or the captured image display mode to the defective pixel detection operation mode by the user via the operation unit 80 (detection operation). As a result, the imaging apparatus 1 starts a defective pixel detection operation.
In the imaging device 1, the user designates the number of times of capturing a dark image via the operation unit 80 (step S101). Here, the dark image is the above-described second image captured in a state where light from the image sensor 12 is blocked. The defect detection unit 20 of the control unit 90 substitutes the variable n for the number of imaging m acquired via the operation unit 80 as the number of imaging of the dark image.
Next, the defect detection unit 20 initializes the variable i by substituting “1” (step S102). Here, the variable i is a variable indicating the number of times (number of images to be captured) of dark images.

Next, the defect detection unit 20 performs a defective pixel detection process using the i-th dark image (step S103). Details of the processing in step S103 will be described later with reference to FIG.
Next, the defect detection unit 20 assigns (i + 1) to the variable i and updates it (step S104).

  Next, the defect detection unit 20 determines whether or not the variable i is larger than the variable n (= m) (step S105). If the defect detection unit 20 determines that the variable i is greater than the variable n, the defect detection unit 20 ends the defective pixel detection operation mode and ends the defective pixel detection process. If the defect detection unit 20 determines that the variable i is equal to or less than the variable n, the defect detection unit 20 returns the process to step S103. That is, the defect detection unit 20 repeats the process of step S103 n times.

Next, the process of step S103 will be described in detail.
FIG. 3 is a flowchart showing a defective pixel detection process in the present embodiment. Here, the defective pixel detection process corresponds to the process of step S103 in FIG.
In FIG. 3, first, the defect detection unit 20 initializes an address for a stored image (x = 0, y = 0) (step S201). Here, the saved image is, for example, a first image stored in the image storage unit 61. Here, the stored image address is, for example, address information of the first image, and is information indicated by a variable x and a variable y.

Next, the defect detection unit 20 substitutes a predetermined defective pixel threshold value for the variable Dth (step S202).
Next, the defect detection unit 20 causes the imaging unit 10 (imaging device 12) to capture the i-th dark image under an imaging condition and a light shielding state that are the same as the imaging condition under which the first image was captured (step S203). . The defect detection unit 20 causes the buffer memory unit 30 to store the i-th dark image data (second image) captured by the imaging unit 10.

  Next, the defect detection unit 20 initializes the address for the captured image (h = 0, v = 0) (step S204). Here, the captured image is, for example, the i-th dark image (second image) that is a dark image captured this time and stored in the buffer memory unit 30. Here, the address for the captured image is, for example, address information of the second image, and is information indicated by the variable h and the variable v.

  Next, the defect detection unit 20 acquires a pixel value S1 (x, y) (first pixel data) corresponding to the address (x, y) of the (i-1) -th stored image (step S205). ). That is, the calculation unit 91 of the defect detection unit 20 reads the pixel value S1 (x, y) corresponding to the address (x, y) in the previous captured image data stored in the image storage unit 61. Note that, for example, in the first defective pixel detection process after manufacturing, the calculation unit 91 uses the initial captured image data stored in the image storage unit 61 as the first image and corresponds to the address (x, y). The pixel value S1 (x, y) to be read is read out.

  Next, the defect detection unit 20 acquires a pixel value S2 (h, v) (second pixel data) corresponding to the address (h, v) of the captured image (i-th image) (step S206). . That is, the calculation unit 91 of the defect detection unit 20 reads the pixel value S2 (h, v) corresponding to the address (h, v) in the captured image data stored in the buffer memory unit 30.

  Next, the defect detection unit 20 determines whether or not the absolute value of (S1 (x, y) −S2 (h, v)) is greater than or equal to a variable Dth indicating the threshold value of the defective pixel (step S207). . That is, the calculation unit 91 calculates the difference (S1 (x, y) −S2 (h, v)) between the read pixel value S1 (x, y) and the pixel value S2 (h, v). , (S1 (x, y) −S2 (h, v)) is calculated. The calculation unit 91 supplies the calculated absolute value of (S1 (x, y) −S2 (h, v)) to the determination unit 92. The determination unit 92 determines whether or not the absolute value of (S1 (x, y) −S2 (h, v)) calculated by the calculation unit 91 is greater than or equal to the variable Dth. The determination unit 92 determines that the address (h, v) of the image sensor 12 is a defective pixel when the absolute value of (S1 (x, y) −S2 (h, v)) is equal to or greater than the variable Dth, and performs processing. Advances to step S208. The determination unit 92 determines that the address (h, v) of the image sensor 12 is not a defective pixel when the absolute value of (S1 (x, y) −S2 (h, v)) is less than the variable Dth. Then, the process proceeds to step S211.

  Next, in step S208, the defect detection unit 20 determines whether or not the value of (S1 (x, y) −S2 (h, v)) is 0 or less. That is, the determination unit 92 determines whether or not the difference (S1 (x, y) −S2 (h, v)) calculated by the calculation unit 91 is a negative value. When the value of (S1 (x, y) −S2 (h, v)) is 0 or less, the determination unit 92 determines the address (h, v) of the image sensor 12 as a later defective pixel, The process proceeds to step S210. The determination unit 92 determines that the address (h, v) of the image sensor 12 is a blinking defective pixel when the value of (S1 (x, y) −S2 (h, v)) is greater than zero. The process proceeds to step S209.

In step S209, the determination unit 92 stores (registers) the address (h, v) of the image sensor 12 in the blinking defect storage unit 63 as a blinking defective pixel.
In step S210, the determination unit 92 stores (registers) the address (h, v) of the image sensor 12 in the defect storage unit 62 as a subsequent defective pixel.

Next, the defect detection unit 20 updates the variable x and the variable h (step S211). That is, the defect detection unit 20 updates by substituting (x + 1) for the variable x and substituting (h + 1) for the variable h.
Next, the defect detection unit 20 determines whether or not the variable x (= variable h) is larger than the maximum value hmax of the variable h (step S212). When the variable x (= variable h) is larger than hmax, the defect detection unit 20 advances the process to step S213. Moreover, the defect detection part 20 returns a process to step S205, when the variable x (= variable h) is below hmax.

Next, in step S213, the defect detection unit 20 initializes the variable x and the variable h (x = 0, h = 0), and updates the variable y and the variable v. That is, the defect detection unit 20 updates the variable y by substituting (y + 1) for the variable y and updates the variable v by substituting (v + 1).
Next, the defect detection unit 20 determines whether or not the variable y (= variable v) is larger than the maximum value vmax of the variable v (step S214). The defect detection unit 20 ends the defective pixel detection process when the variable y (= variable v) is larger than vmax. Moreover, the defect detection part 20 returns a process to step S205, when the variable y (= variable v) is below vmax. When the defect detection unit 20 ends the defective pixel detection process, the i-th dark image (second image) captured in the current process is used as the next first image (previously captured image data). Is stored in the image storage unit 61.

As described above, the imaging apparatus 1 according to the present embodiment performs the defective pixel detection process illustrated in FIG. 3 described above n times designated by the user, and subsequently causes defective pixels and blinking defective pixels. Is detected. The imaging apparatus 1 stores (registers) the detected defective pixel and the blinking defective pixel in the defect storage unit 62 and the blinking defect storage unit 63, respectively.
The defect correction unit 93 of the imaging apparatus 1 includes a defect storage unit 62 in which an image (third image) obtained by imaging the subject or the like by the imaging device 12 is captured in the above-described defective pixel detection process, and blinking property. Based on the defect storage unit 63, correction processing is performed.

As described above, in the imaging device 1 according to the present embodiment, the imaging element 12 captures an image by generating a pixel signal corresponding to light. The defect detection unit 20 includes a first image (for example, initial captured image data or previous captured image data) captured in advance by the image sensor 12 and a second image (for example, the above-described dark image captured this time). Based on the comparison result, a defective pixel included in the image sensor is detected. Here, the second image is captured by the image sensor 12 under the same imaging conditions as the first image.
Thereby, since the imaging device 1 in this embodiment detects a defective pixel based on the comparison result between the first image captured in advance and the newly captured second image, the subsequent defective pixel is detected. can do. Furthermore, since the imaging device 1 according to the present embodiment compares the first image and the second image captured under the same imaging conditions, it is possible to accurately detect the subsequent defective pixels. Therefore, the imaging device 1 in the present embodiment can accurately detect defective pixels.

In the present embodiment, the defect detection unit 20 includes the first pixel data S1 (x, y) (first pixel signal) in the first image and the second pixel data S2 (h) in the second image. , V) The first image and the second image are compared based on the calculation result with (second pixel signal). The defect detection unit 20 detects a defective pixel based on the comparison result. Note that the second pixel data S2 is a pixel position (h, v) (for example, equal pixel position) of the second image corresponding to the pixel position (x, y) of the first pixel data S1 (x, y). ) Pixel data (pixel signal).
Thereby, since the defect detection unit 20 compares the pixel data at the corresponding pixel positions of the first image and the second image, the position of the defective pixel can be accurately detected. That is, the imaging device 1 in the present embodiment can accurately detect defective pixels.

In the present embodiment, the defect detection unit 20 includes a calculation unit 91 and a determination unit 92. The calculation unit 91 calculates a difference (S1 (x, y) −S2 (h, v)) between the first pixel data S1 (x, y) and the second pixel data S2 (h, v). The determination unit 92 compares the first image with the second image based on the difference (S1 (x, y) −S2 (h, v)) calculated by the calculation unit 91, and determines the comparison result. Based on this, it is determined whether or not the pixel corresponding to the pixel position is a defective pixel.
Thereby, since the defect detection unit 20 compares the first image and the second image based on the difference in pixel data at corresponding pixel positions, it is possible to accurately detect the position of the defective pixel with a simple configuration. it can. That is, the imaging device 1 in the present embodiment can accurately detect defective pixels with a simple configuration.

In addition, the imaging apparatus 1 according to the present embodiment includes a defect storage unit 62 that stores position information (for example, an address) indicating a pixel position corresponding to a defective pixel. The defect detection unit 20 causes the defect storage unit 62 to store position information indicating the pixel position corresponding to the detected defective pixel.
Thereby, since the position information of the defective pixel is registered in the defect storage unit 62, the imaging apparatus 1 in the present embodiment performs image processing using the position information of the defective pixel stored in the defect storage unit 62. Can do. For example, the imaging apparatus 1 according to the present embodiment has pixel data of a defective pixel position of an image (third image) captured by the imaging element 12 based on position information of the defective pixel stored in the defect storage unit 62. Can be corrected.

In the present embodiment, the first image and the second image are images captured with the image sensor 12 shielded from light.
Thereby, the imaging device 1 in this embodiment can be made into the same imaging condition by a simple means. Furthermore, since an image (dark image) captured with the image sensor 12 shielded from light can efficiently detect defective pixels, the image pickup apparatus 1 according to the present embodiment accurately and efficiently detects defective pixels. can do.

In the present embodiment, the defect detection unit 20 causes the image sensor 12 to capture the second image a plurality of times. The defect detection unit 20 uses the second image captured one time before as the first image, and based on the comparison result between the first image and each of the plurality of captured second images, the defect pixel, and the defect Among the pixels, a blinking (variable) defective pixel is detected. That is, the defect detection unit 20 determines the previously captured second image as the first image, and based on the comparison result between the newly captured second image and the first image, the defect pixel and the defect A variable defective pixel that occurs discontinuously in pixels is detected.
Thereby, the imaging device 1 according to the present embodiment can accurately detect a defective pixel having blinking characteristics (variability) as well as a subsequent defective pixel. That is, the imaging apparatus 1 according to the present embodiment can efficiently detect late defective pixels and blinking (variable) defective pixels.
Moreover, the imaging device 1 in this embodiment can improve the detection accuracy of the blinking defective pixel by repeating the detection operation.

The imaging apparatus 1 according to the present embodiment includes a blinking defect storage unit 63 that stores position information indicating pixel positions corresponding to blinking (variable) defective pixels. The defect detection unit 20 causes the blinking defect storage unit 63 to store position information indicating pixel positions corresponding to the detected blinking (variable) defective pixels.
Thereby, since the position information of the defective pixel is registered in the blinking defect storage unit 63, the imaging device 1 in the present embodiment is configured so that the defect detection unit 20 has the blinking property stored in the blinking defect storage unit 63. Image processing using position information of defective pixels can be performed.

In addition, the imaging apparatus 1 according to the present embodiment corrects an image (third image) captured by the imaging element 12 based on position information corresponding to the defective pixel detected by the defect detection unit 20. 93.
Thereby, the imaging device 1 according to the present embodiment can detect the defective pixel position of the image (third image) captured by the imaging element 12 based on the positional information of the defective pixel accurately detected by the defect detection unit 20. Pixel data can be corrected.

[Second Embodiment]
Next, the imaging device 1 in the second embodiment which is another embodiment will be described.
The configuration of the imaging apparatus 1 in the second embodiment is the same as the configuration in the first embodiment shown in FIG. The imaging device 1 in the second embodiment is different from the imaging device 1 in the first embodiment in the defective pixel detection processing by the defect detection unit 20.
In the present embodiment, the defect detection unit 20 causes the image sensor 12 to capture the second image a plurality of times, and based on the comparison result between the first image and each of the captured plurality of second images, the defect pixel ( A late defective pixel) is detected. Then, the defect detection unit 20 compares the plurality of second images, and detects a blinking (variable) defective pixel included in the defective pixel based on the comparison result of the plurality of second images. .

Next, the operation of the imaging device 1 in the present embodiment will be described.
The detection operation of the defective pixel of the imaging apparatus 1 in the present embodiment is the same as the flowchart in the first embodiment shown in FIG.
In the present embodiment, the process in step S103 is different from the process in the first embodiment. Next, the process in step S103 will be described.
FIG. 4 is a flowchart showing defective pixel detection processing in the present embodiment. Here, the defective pixel detection process corresponds to the process of step S103 in FIG.
In FIG. 4, the process from step S201 to step S204, the process from step S206, and the process from step S209 to step S214 are the same as those in FIG.

  In step S205A after the processing of step S204, the defect detection unit 20 acquires a pixel value S0 (x, y) (first pixel data) corresponding to the address (x, y) of the initial saved image. That is, the calculation unit 91 of the defect detection unit 20 calculates the pixel value S0 (x, y) corresponding to the address (x, y) in the initial captured image data (initial stored image data) stored in the image storage unit 61. read out. The calculation unit 91 reads the pixel value S1 (x, y) corresponding to the address (x, y) using the initial captured image data stored in the image storage unit 61 as a first image.

Next, the defect detection unit 20 acquires the pixel value S1 (x, y) corresponding to the address (x, y) of the (i-1) th stored image (step S205B). That is, the calculation unit 91 of the defect detection unit 20 reads the pixel value S1 (x, y) corresponding to the address (x, y) in the previous captured image data stored in the image storage unit 61. Note that the calculation unit 91 sets the previous captured image data stored in the image storage unit 61 as one of the plurality of second images, and the pixel value S1 (x, y) corresponding to the address (x, y). ).
The defect detection unit 20 advances the process to step S207a after executing the process of step S206 after the process of step S205B.

  Next, in step S207a, the defect detection unit 20 determines whether or not the absolute value of (S2 (h, v) −S0 (x, y)) is equal to or larger than the variable Dth indicating the threshold value of the defective pixel. . That is, the calculation unit 91 calculates a difference (S2 (h, v) −S0 (x, y)) between the read pixel value S2 (h, v) and the pixel value S0 (x, y). , (S2 (h, v) −S0 (x, y)) is calculated. The calculation unit 91 supplies the calculated absolute value of (S2 (h, v) −S0 (x, y)) to the determination unit 92. The determination unit 92 determines whether or not the absolute value of (S2 (h, v) −S0 (x, y)) calculated by the calculation unit 91 is greater than or equal to the variable Dth. When the absolute value of (S2 (h, v) −S0 (x, y)) is equal to or greater than the variable Dth, the determination unit 92 determines that the address (h, v) of the image sensor 12 is a late defective pixel. Then, the process proceeds to step S210. Further, the determination unit 92 determines that the address (h, v) of the image sensor 12 is a late defective pixel when the absolute value of (S2 (h, v) −S0 (x, y)) is less than the variable Dth. Otherwise, the process proceeds to step S208a.

  Next, in step S208a, the defect detection unit 20 determines whether or not the value of (S1 (x, y) −S2 (h, v)) is greater than or equal to the variable Dth. That is, the calculation unit 91 calculates a difference S1 (x, y) −S2 (h, v)) between the read pixel value S1 (x, y) and the pixel value S2 (h, v). The determination unit 92 determines whether or not the difference (S1 (x, y) −S2 (h, v)) calculated by the calculation unit 91 is equal to or greater than the variable Dth. When the value of (S1 (x, y) −S2 (h, v)) is greater than or equal to the variable Dth, the determination unit 92 sets the address (h, v) of the image sensor 12 to a blinking (variable) defect. The pixel is determined, and the process proceeds to step S209. The determination unit 92 determines that the address (h, v) of the imaging element 12 is not a defective pixel when the value of (S1 (x, y) −S2 (h, v)) is less than the variable Dth. Then, the process proceeds to step S211.

The processing after step S209 is the same as the processing of the first embodiment shown in FIG.
The defect detection unit 20 stores the i-th dark image (second image) captured in the current process in the image storage unit 61 as the previous captured image data when the defective pixel detection process ends. Let

  As described above, in the present embodiment, the defect detection unit 20 performs the defective pixel detection process shown in FIG. 4 described above n times designated by the user, and subsequently detects the defective pixel and the blinking property. Detect defective pixels. The defect detection unit 20 compares the initial captured image data captured in advance as the first image with the i-th captured image data (second image), and based on the comparison result, the subsequent defect Detect a pixel. Further, the defect detection unit 20 performs the previous captured image data (previous second image) that is the previous (i−1) dark image and the current captured image data that is the current (i) dark image. (Second image of this time) and a blinking defective pixel is detected based on the comparison result. That is, the defect detection unit 20 determines that the pixel position determined to be a defective pixel in the previous second image is not a defective pixel in the current second image (the pixel value decreases). The pixel position is determined to be a blinking defective pixel.

As described above, in the imaging apparatus according to the present embodiment, the defect detection unit 20 causes the imaging element 12 to capture the second image a plurality of times under the imaging condition equal to that of the first image (initial captured image data). The defect detection unit 20 detects a later defective pixel based on a comparison result between each of the plurality of captured second images and the first image captured in advance. And the defect detection part 20 detects the blinking (variable) defective pixel which generate | occur | produces discontinuously temporally contained in a defective pixel based on the comparison result of several 2nd images.
Thereby, the imaging device 1 according to the present embodiment can accurately detect a defective pixel having blinking characteristics (variability) as well as a subsequent defective pixel. That is, the imaging apparatus 1 according to the present embodiment can efficiently detect late defective pixels and blinking (variable) defective pixels. Therefore, the imaging device 1 in the present embodiment can accurately detect defective pixels as in the first embodiment.
Moreover, the imaging device 1 in this embodiment can improve the detection accuracy of the blinking defective pixel by repeating the detection operation.

[Third Embodiment]
Next, the imaging device 1 in the third embodiment will be described.
FIG. 5 is a block diagram illustrating the imaging apparatus 1 according to the present embodiment.
In this figure, the same components as those in FIG. 1 are denoted by the same reference numerals, and the description thereof is omitted. The imaging device 1 in the present embodiment is different from the first and second embodiments shown in FIG. 1 in that the imaging unit 10 includes a temperature sensor 14. In addition, the imaging apparatus 1 according to the present embodiment includes the temperature sensor 14, so that the defective pixel detection process in the defect detection unit 20 is different.

The temperature sensor 14 is arranged near or around the image sensor 12, detects the temperature of the image sensor 12, and supplies the detected temperature to the controller 90.
In addition, the image storage unit 61 in the present embodiment stores image data (first image) captured in advance in association with the temperature of the imaging element 12 detected when the first image is captured. Note that the image storage unit 61 stores two pieces of image data, initial captured image data (initially stored image data) and previous captured image data, and the temperature in the image sensor 12 when each image is captured.

In the first and second embodiments, the defect detection unit 20 performs control to capture the second image under the same imaging conditions as the first image. However, depending on the temperature difference of the image sensor 12, There may be a difference between the dark current value included in the first image and the dark current value included in the second image. This difference due to the dark current value may affect the difference between the pixel data in the first image and the pixel data in the second image.
Therefore, the defect detection unit 20 according to the present embodiment executes a defective pixel detection process so as to reduce the influence of the dark current value due to the temperature difference of the image sensor 12.

  In the defect detection unit 20 according to the present embodiment, the difference between the temperature of the image sensor 12 detected by the temperature sensor 14 and the temperature of the image sensor 12 when the first image is captured is equal to or less than a predetermined threshold. In this case, or when the two temperatures are equal, the image sensor 12 is caused to capture the second image to detect defective pixels. Here, two temperatures being equal include two temperatures being approximately equal.

Next, the operation of the imaging device 1 in the present embodiment will be described.
FIG. 6 is a flowchart illustrating the defective pixel detection operation of the imaging apparatus 1 according to the present embodiment.
In FIG. 6, as in the flowchart shown in FIG. 2, first, the imaging apparatus 1 is shifted from the imaging operation mode or the captured image display mode to the defective pixel detection operation mode by the user via the operation unit 80. (Detection operation). As a result, the imaging apparatus 1 starts a defective pixel detection operation.

In the imaging device 1, the user designates the number of times of capturing a dark image via the operation unit 80 (step S301). Here, the dark image is the above-described second image captured in a state where light from the image sensor 12 is blocked. The defect detection unit 20 of the control unit 90 substitutes the variable n for the number of imaging m acquired via the operation unit 80 as the number of imaging of the dark image.
Next, the defect detection unit 20 operates the image sensor 12 continuously to acquire the temperature of the image sensor 12 (step S302). That is, the defect detection unit 20 causes the image sensor 12 to continuously operate and gradually increases the temperature of the image sensor 12. The defect detection unit 20 acquires the temperature of the image sensor 12 detected by the temperature sensor 14.

  Next, the defect detection unit 20 determines whether or not the acquisition temperature of the stored image (first image) is equal to the temperature of the image sensor 12 acquired in step S302 (step S303). That is, the defect detection unit 20 reads the temperature of the image sensor 12 when the first image stored in association with the first image stored in the image storage unit 61 is captured. Next, the defect detection unit 20 determines whether or not the temperature of the image sensor 12 acquired in step S302 is equal to the acquisition temperature of the stored image (first image). Here, in order for the acquired temperature of the image sensor 12 and the acquired temperature of the stored image (first image) to be equal, the acquired temperature of the image sensor 12 and the acquired temperature of the stored image (first image) Are also included. In addition, the defect detection unit 20 determines whether or not the difference between the temperature of the image sensor 12 detected by the temperature sensor 14 and the temperature of the image sensor 12 when the first image is captured is equal to or less than a predetermined threshold value. Thus, it may be determined that the acquired temperature of the image sensor 12 and the acquired temperature of the stored image (first image) are substantially equal.

  If the defect detection unit 20 determines that the temperature of the image sensor 12 acquired in step S302 is equal to the acquisition temperature of the stored image (first image), the process proceeds to step S304. If the defect detection unit 20 determines that the temperature of the image sensor 12 acquired in step S302 is not equal to the acquisition temperature of the stored image (first image), the defect detection unit 20 returns the process to step S302.

The subsequent processing from step S305 to step S307 corresponds to step S102 to step S205 in FIG. 2 and is the same processing. Therefore, description of the processing from step S305 to step S307 is omitted here.
In addition, the process of step S305 (defective pixel detection process) in this embodiment is the same as that in the first or second embodiment shown in FIG. 3 or FIG.

As described above, the imaging apparatus 1 according to the present embodiment includes the temperature sensor 14 that detects the temperature of the imaging element 12. And the defect detection part 20 is when the difference of the temperature of the image pick-up element 12 detected by the temperature sensor 14 and the temperature of the image pick-up element 12 at the time of a 1st image being imaged becomes below a predetermined threshold value. Then, the second image is captured by the image sensor 12. The defect detection unit 20 detects a defective pixel based on a comparison result between the first image captured in advance and the captured second image.
Thereby, since the influence of the dark current due to the temperature difference can be reduced, the imaging device 1 in the present embodiment can accurately detect the defective pixel.

[Fourth Embodiment]
Next, the imaging device 1 in the fourth embodiment will be described.
FIG. 7 is a block diagram illustrating the imaging apparatus 1 according to the present embodiment.
In this figure, the same components as those in FIG. 5 are denoted by the same reference numerals, and the description thereof is omitted. The imaging apparatus 1 in the present embodiment is different from the third embodiment shown in FIG. 5 in that the defect detection unit 20 includes a temperature correction unit 94. Further, the imaging apparatus 1 according to the present embodiment includes the temperature correction unit 94, so that the defective pixel detection process in the defect detection unit 20 is different from that of the third embodiment.
In the third embodiment, the defect detection unit 20 captures the dark current value by capturing the second image when the temperature is equal to the temperature of the image sensor 12 when the first image is captured. Control is performed to reduce the impact. On the other hand, the defect detection unit 20 in the present embodiment performs control so as to reduce the influence of the dark current value by correcting the captured second image based on the temperature difference of the image sensor 12.

That is, the defect detection unit 20 according to the present embodiment detects the temperature of the image sensor 12 detected by the temperature sensor 14 when the second image is captured and the temperature of the image sensor 12 when the first image is captured. Based on the difference, a temperature correction unit 94 that corrects the second image is provided.
The temperature correction unit 94 (second correction unit) includes the temperature detected by the temperature sensor 14 when the second image calculated by the calculation unit 91 is captured and the image sensor 12 when the first image is captured. A difference from the temperature is acquired, and the pixel data of the second image is corrected based on the acquired temperature difference. In addition, it is known that the dark current value generated in the image sensor 12 generally depends on temperature. Therefore, the temperature correction unit 94 can estimate the difference in dark current value between the first image and the second image based on the above-described temperature difference. Therefore, the temperature correction unit 94 can correct the pixel data of the second image based on the above-described temperature difference. The temperature correction unit 94 stores the corrected second image data in the buffer memory unit 30.

In addition, the calculating part 91 in this embodiment reads the temperature of the image pick-up element 12 when the 1st image memorize | stored in the image memory | storage part 61 is imaged. Further, the calculation unit 91 acquires the temperature of the image sensor 12 when the second image is captured from the temperature sensor 14, and the temperature and the temperature sensor 14 of the image sensor 12 when the first image is captured are used. The difference with the detected temperature of the image sensor 12 is calculated. The calculation unit 91 supplies the calculated temperature difference to the temperature correction unit 94.
The calculation unit 91 also includes first pixel data (first pixel signal) in the first image and second pixel data (second pixel signal) in the second image corrected by the temperature correction unit 94. ) Is calculated. The calculation unit 91 supplies the calculated calculation result (difference value) to the determination unit 92.
In addition, the determination unit 92 in the present embodiment compares the first image and the corrected second image for each pixel position based on the difference calculated by the calculation unit 91, and based on the comparison result. Then, it is determined whether or not the pixel corresponding to the compared pixel position is a defective pixel.

Next, the operation of the imaging device 1 in the present embodiment will be described.
The detection operation of the defective pixel of the imaging device 1 in the present embodiment is the same as the flowchart in the first and second embodiments shown in FIG.
In the present embodiment, the processing in step S103 is different from the processing in the first and second embodiments. Next, the processing in step S103 will be described.
FIG. 8 is a flowchart showing a defective pixel detection process in the present embodiment. Here, the defective pixel detection process corresponds to the process of step S103 in FIG.
In FIG. 8, first, the defect detection unit 20 initializes an address for a stored image (x = 0, y = 0) (step S401). Here, the saved image is, for example, a first image stored in the image storage unit 61. Here, the stored image address is, for example, address information of the first image, and is information indicated by a variable x and a variable y.

Next, the defect detection unit 20 substitutes a predetermined defective pixel threshold value for the variable Dth (step S402).
Next, the defect detection unit 20 acquires the temperature of the image sensor 12 from the temperature sensor 14 (step S403).

Next, the defect detection unit 20 causes the imaging unit 10 (imaging device 12) to capture the i-th dark image (second image), and captures i based on the temperature of the imaging device 12 from the temperature sensor 14. The temperature of the first dark image is corrected (step S404). That is, the defect detection unit 20 causes the imaging unit 10 (imaging element 12) to capture the i-th dark image under an imaging condition and a light shielding state that are the same as the imaging condition under which the first image is captured. The defect detection unit 20 stores the i-th dark image data (second image) captured by the imaging unit 10 in the buffer memory unit 30.
Further, the calculation unit 91 of the defect detection unit 20 reads the temperature of the image sensor 12 when the first image stored in the image storage unit 61 is captured. Further, the calculation unit 91 acquires the temperature of the image sensor 12 when the second image is captured from the temperature sensor 14, and the temperature and the temperature sensor 14 of the image sensor 12 when the first image is captured are used. The difference with the detected temperature of the image sensor 12 is calculated. The calculation unit 91 supplies the calculated temperature difference to the temperature correction unit 94. The temperature correction unit 94 acquires the temperature difference calculated by the calculation unit 91, and corrects the pixel data of the second image based on the acquired temperature difference. The temperature correction unit 94 stores the corrected second image data in the buffer memory unit 30.

  Next, the defect detection unit 20 initializes the address for the captured image (h = 0, v = 0) (step S405). Here, the captured image is, for example, the i-th dark image (second image) that is a dark image captured this time and stored in the buffer memory unit 30. Here, the address for the captured image is, for example, address information of the second image, and is information indicated by the variable h and the variable v.

  Next, the defect detection unit 20 acquires a pixel value S1 (x, y) (first pixel data) corresponding to the address (x, y) of the (i-1) -th stored image (step S406). ). That is, the calculation unit 91 of the defect detection unit 20 reads the pixel value S1 (x, y) corresponding to the address (x, y) in the previous captured image data stored in the image storage unit 61. Note that, for example, in the first defective pixel detection process after manufacturing, the calculation unit 91 uses the initial captured image data stored in the image storage unit 61 as the first image and corresponds to the address (x, y). The pixel value S1 (x, y) to be read is read out.

  Next, the defect detection unit 20 acquires a pixel value S2 (h, v) (second pixel data) corresponding to the address (h, v) of the temperature-corrected captured image (i-th image). (Step S407). That is, the calculation unit 91 of the defect detection unit 20 reads the pixel value S2 (h, v) corresponding to the address (h, v) in the temperature-corrected captured image data stored in the buffer memory unit 30.

  The subsequent processing from step S408 to step S415 corresponds to the processing from step S207 to step S214 in FIG. 3, and is the same processing. Therefore, the description of the processing from step S408 to step S415 is omitted here.

As described above, the imaging device 1 according to the present embodiment includes the temperature sensor 14 that detects the temperature of the imaging element 12 and the temperature of the imaging element 12 that is detected by the temperature sensor 14 when the second image is captured. A temperature correction unit 94 that corrects the second image based on the difference from the temperature of the image sensor 12 when the first image is captured is provided. The defect detection unit 20 detects defective pixels based on the second image corrected by the temperature correction unit 94 and the first image.
Thereby, since the influence of the dark current due to the temperature difference can be reduced, the imaging device 1 in the present embodiment can accurately detect the defective pixel.

[Fifth Embodiment]
Next, an imaging apparatus 1 according to a fifth embodiment, which is another embodiment that reduces the influence of dark current due to temperature differences, will be described.
The configuration of the imaging apparatus 1 in the fifth embodiment is the same as the configuration in the third embodiment shown in FIG. The imaging apparatus 1 according to the fifth embodiment is different from the imaging apparatus 1 according to the third and fourth embodiments in the process of reducing the influence of dark current due to the temperature difference by the defect detection unit 20.

In the present embodiment, the image storage unit 61 stores a plurality of first images captured in advance at different temperatures.
In addition, the defect detection unit 20 includes a plurality of first images stored in the image storage unit 61 according to the temperature of the image sensor 12 detected by the temperature sensor 14 when the second image is captured. And detecting defective pixels based on the selected first image and second image. The plurality of first images stored in the image storage unit 61 are classified into a plurality of predetermined temperature ranges, for example. For example, the defect detection unit 20 may detect the plurality of first images based on which of the predetermined temperature ranges the temperature of the image sensor 12 detected by the temperature sensor 14 corresponds to. Select one of them.
Note that the defect detection unit 20 in the present embodiment detects later defective pixels and blinking (variable) defective pixels by the same processing as in the second embodiment.

Next, the operation of the imaging device 1 in the present embodiment will be described.
The detection operation of the defective pixel of the imaging device 1 in the present embodiment is the same as the flowchart in the first and second embodiments shown in FIG.
In the present embodiment, part of the processing in step S103 is different from the processing in the second and fourth embodiments. Next, the processing in step S103 will be described.

FIG. 9 is a flowchart showing defective pixel detection processing in the present embodiment. Here, the defective pixel detection process corresponds to the process of step S103 in FIG.
In FIG. 9, the processing from step S401 to step S403 is the same as that of the fourth embodiment shown in FIG. 8, and the description of the processing will be omitted.

In step S <b> 404 a, the defect detection unit 20 causes the imaging unit 10 (imaging device 12) to capture the i-th dark image under an imaging condition and a light shielding state that are the same as the imaging condition under which the first image is captured. The defect detection unit 20 causes the buffer memory unit 30 to store the i-th dark image data (second image) captured by the imaging unit 10.
Next, the defect detection unit 20 initializes the address for the captured image (h = 0, v = 0) (step S405).

Next, the defect detection unit 20 acquires the pixel value S0 (x, y) (first pixel data) of the address (x, y) of the initial storage image corresponding to the temperature of the image sensor 12 acquired in step S403. (Step S406A). That is, the defect detection unit 20 selects one of the plurality of initial captured image data (initially stored image data) stored in the image storage unit 61 corresponding to the temperature of the image sensor 12. The calculation unit 91 of the defect detection unit 20 reads the pixel value S0 (x, y) corresponding to the address (x, y) in the selected initial captured image data (initially stored image data). The calculation unit 91 reads the pixel value S1 (x, y) corresponding to the address (x, y) using the initial captured image data stored in the image storage unit 61 as a first image.

  Next, the defect detection unit 20 acquires the pixel value S1 (x, y) corresponding to the address (x, y) of the (i-1) -th stored image (step S406B). That is, the calculation unit 91 of the defect detection unit 20 reads the pixel value S1 (x, y) corresponding to the address (x, y) in the previous captured image data stored in the image storage unit 61. Note that the calculation unit 91 sets the previous captured image data stored in the image storage unit 61 as one of the plurality of second images, and the pixel value S1 (x, y) corresponding to the address (x, y). ).

Next, the defect detection unit 20 acquires a pixel value S2 (h, v) (second pixel data) corresponding to the address (h, v) of the captured image (i-th image) (step S407a). . That is, the calculation unit 91 of the defect detection unit 20 reads the pixel value S2 (h, v) corresponding to the address (h, v) in the captured image data stored in the buffer memory unit 30.
The subsequent steps S408a, S409a, and steps S410 to S415 correspond to the steps S207a, S208a, and steps S209 to S214 in FIG. 4, and are the same as those in the second embodiment. Here, description of the processing of step S408a, step S409a, and step S410 to step S415 is omitted.

As described above, the imaging device 1 according to the present embodiment includes the image storage unit 61 that stores a plurality of first images captured in advance at different temperatures, and the temperature sensor 14 that detects the temperature of the imaging element 12. It has. Then, the defect detection unit 20 includes a plurality of first images stored in the image storage unit 61 according to the temperature of the image sensor 12 detected by the temperature sensor 14 when the second image is captured. To select the first image. The defect detection unit 20 detects a defective pixel based on the selected first image and second image.
Thereby, since the influence of the dark current due to the temperature difference can be reduced, the imaging device 1 in the present embodiment can accurately detect the defective pixel.

The present invention is not limited to the above embodiments, and can be modified without departing from the spirit of the present invention.
For example, in each of the embodiments described above, the imaging apparatus 1 has described the form in which the user starts the defective pixel detection operation via the operation unit 80. However, the defective pixel detection operation is started by other means. Form may be sufficient. For example, the defect detection unit 20 may be configured to detect a defective pixel by causing the imaging device to capture the second image every predetermined period. In this case, even if the user does not perform the defective pixel detection operation via the operation unit 80, the defective pixel detection operation is started every predetermined period. Therefore, the imaging apparatus 1 can always execute the defect correction process based on the latest defective pixel information.

Further, in each of the above embodiments, the configuration in which the control unit 90 includes the defect detection unit 20 has been described. However, the image processing unit 40 may have a configuration in which the defect detection unit 20 or a part of the defect detection unit 20 is included. Moreover, although the control part 90 demonstrated the form provided with the defect correction part 93, the form with which the defect detection part 20 is provided with the defect correction part 93 may be sufficient, and the form with which the image process part 40 is provided with the defect correction part 93 may be sufficient.
Further, in the fourth embodiment, the form in which the defect detection unit 20 includes the temperature correction unit 94 has been described. However, a form in which the temperature correction unit 94 is provided outside the defect detection unit 20 may be used. For example, the control unit 90 outside the image processing unit 40 or the defect detection unit 20 may include the temperature correction unit 94.

  In each of the above embodiments, as an example, the defect detection unit 20 is based on the difference between two images (for example, the difference between the first image and the second image, the difference between the second images). Although the form which compares two images was demonstrated, the form which compares two images based on another arithmetic processing may be sufficient. For example, the defect detection unit 20 may be configured to compare two images using a ratio instead of the difference.

  In each of the above embodiments, the defect detection unit 20 has been described as using a dark image captured by shielding the image sensor 12. However, the defect detection unit 20 uses an image captured from a predetermined subject that can easily detect defective pixels. The form which detects a defective pixel may be sufficient.

  In the fifth embodiment, the defect detection unit 20 has been described as selecting one of the plurality of first images according to the temperature of the image sensor 12. A mode in which a first image is selected and an image corrected by interpolation based on the two or more selected first images may be used as the first image.

  Further, in the above-described FIGS. 3, 4, 8, and 9, the form using the two types of address variables of the variable x and the variable y and the variable h and the variable v has been described. However, only one of the addresses is described. A form using variables may be used. Moreover, although the defect memory | storage part 62 and the blinking defect memory | storage part 63 demonstrated the form which memorize | stores the address information (position information) of a defective pixel, the map information comprised from the flag corresponding to each pixel of the image pick-up element 12 was shown. The form to memorize | store may be sufficient. In this case, the defect storage unit 62 and the blinking defect storage unit 63 may store, for example, map information in which the flag corresponding to the defective pixel is “1” and the flag corresponding to the normal pixel is “0”. .

  The imaging apparatus 1 described above has a computer system inside. The defective pixel detection process described above is stored in a computer-readable recording medium in the form of a program, and the above process is performed by the computer reading and executing this program. Here, the computer-readable recording medium means a magnetic disk, a magneto-optical disk, a CD-ROM, a DVD-ROM, a semiconductor memory, or the like. Alternatively, the computer program may be distributed to the computer via a communication line, and the computer that has received the distribution may execute the program.

  DESCRIPTION OF SYMBOLS 1 ... Imaging device, 12 ... Image sensor, 14 ... Temperature sensor, 20 ... Defect detection part, 62 ... Defect storage part, 63 ... Flashing defect storage part, 91 ... Calculation part, 92 ... Determination part, 93 ... Defect correction part 94 ... Temperature correction unit

Claims (14)

An image sensor that captures an image by generating a pixel signal corresponding to the light; and
Based on a comparison result between the first image captured by the image sensor and the second image captured by the image sensor under the same imaging condition as the first image, defective pixels included in the image sensor are determined. An image pickup apparatus comprising: a detection unit that detects. The detector is
Based on the calculation result of the first pixel signal in the first image and the second pixel signal in the second image corresponding to the pixel position of the first pixel signal, the first image and the first image The imaging device according to claim 1, wherein the image is compared with two images and the defective pixel is detected based on the comparison result. The detector is
An arithmetic unit for calculating a difference between the first pixel signal and the second pixel signal;
The first image and the second image are compared based on the difference calculated by the calculation unit, and whether or not a pixel corresponding to the pixel position is the defective pixel based on the comparison result The imaging apparatus according to claim 2, further comprising: a determination unit that determines whether or not. A defect storage unit that stores position information indicating a pixel position corresponding to the defective pixel;
The detector is
The position information which shows the pixel position corresponding to the detected said defective pixel is memorize | stored in the said defect memory | storage part. The imaging device as described in any one of Claims 1-3 characterized by the above-mentioned. The imaging device according to any one of claims 1 to 4, wherein the first image and the second image are images captured by shielding the imaging element. The detector is
The previously captured second image is defined as the first image, and the defective pixel and the defective pixel are determined based on a comparison result between the newly captured second image and the first image. The imaging apparatus according to any one of claims 1 to 5, wherein a variable defective pixel that occurs discontinuously in time is detected. The detector is
The imaging device picks up the second image a plurality of times, and based on a comparison result between the plurality of second images, a variable defective pixel that occurs discontinuously in time among the defective pixels. It detects. The imaging device as described in any one of Claims 1-5 characterized by the above-mentioned. The imaging apparatus according to claim 7, wherein the defective pixel is detected based on a comparison result between each of the plurality of second images and the first image captured in advance. A variable defect storage unit that stores position information indicating a pixel position corresponding to the variable defect pixel;
The detector is
9. The imaging apparatus according to claim 6, wherein position information indicating a pixel position corresponding to the detected variable defect pixel is stored in the variable defect storage unit. A first correction unit that corrects a third image picked up by the image pickup device based on position information indicating a pixel position corresponding to the defective pixel detected by the detection unit. The imaging device according to any one of claims 1 to 8. A temperature sensor for detecting the temperature of the image sensor;
The detector is
When the difference between the temperature of the image sensor detected by the temperature sensor and the temperature of the image sensor when the first image is captured is equal to or less than a predetermined threshold, the second image is The imaging device according to claim 1, wherein the defective pixel is detected by causing the imaging device to capture an image. A temperature sensor for detecting the temperature of the image sensor;
Based on the difference between the temperature of the image sensor detected by the temperature sensor when the second image is captured and the temperature of the image sensor when the first image is captured, the second image A second correction unit for correcting the image,
The detector is
The defective pixel is detected based on the second image corrected by the second correction unit and the first image. 11. The imaging device described in 1. An image storage unit that stores a plurality of first images captured in advance at different temperatures;
A temperature sensor for detecting the temperature of the image sensor;
The detector is
The first image out of the plurality of first images stored in the image storage unit according to the temperature of the imaging element detected by the temperature sensor when the second image is captured. The imaging device according to claim 1, wherein the defective pixel is detected based on the selected first image and the second image. . The detector is
14. The defective pixel is detected by causing the imaging device to capture the second image every predetermined period of time, and detecting the defective pixel. Imaging device.

Images