JPH11355667A - Picture element signal processor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a picture element signal processor capable of detecting defective picture elements at a high speed with a small memory capacity. SOLUTION: This picture element signal processor is provided with a first photoelectric conversion element row L1 where plural photoelectric conversion elements for generating picture element signals by photoelectric conversion are arranged, a second photoelectric conversion element row L2 adjacent to the first photoelectric conversion element row which is a photoelectric conversion element row where the plural photoelectric conversion elements for generating the picture element signals by the photoelectric conversion are arranged, picture element signal output means 14 and 15 for transferring and outputting picture element signals including at least the picture element signals generated by the first and second photoelectric conversion element rows as one output row and a defect detection means for detecting whether or not an object picture element signal in one row is the picture element signal generated by the photoelectric conversion element provided with a defect based on the picture element signals of one output row outputted by the picture element signal output means.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image signal processing technique, and more particularly to a technique for detecting a pixel defect in an image.

[0002]

2. Description of the Related Art FIG.
FIG. 2 is a plan view showing the configuration of the first embodiment.

[0005] The solid-state image sensor 20 has a plurality of photodiodes 21 arranged in a two-dimensional matrix.
The photodiode 21 converts the received light into electric charges and stores the charges. The vertical charge transfer path (VCCD) 22 reads charges from the photodiodes 21 and transfers the charges in the vertical direction (from top to bottom).

[0004] A horizontal charge transfer path (HCCD) 24 receives charges from the vertical charge transfer path 22 and transfers the charges in the horizontal direction (from right to left). First, the horizontal charge transfer path 24
Transfers pixel signals (charges) D1 to D5 generated by the photodiodes 21 in the first row L1. Subsequently, the horizontal charge transfer path 24 transfers pixel signals (charges) D1 to D5 generated by the photodiodes 21 in the second row L2, the third row L3, the fourth row L4, and the fifth row L5 in units of rows. Transfer sequentially.

[0005] The output section 25 outputs a predetermined voltage in accordance with the amount of charge of each pixel transferred from the horizontal charge transfer path 24. The output unit sequentially outputs the pixel signals of the first row L1 to the fifth row L5 in row units.

The solid-state imaging device 20 is used, for example, in a video camera, and includes a large number of photodiodes (pixels) 2.
One. Some of these many photodiodes 21 have defects due to manufacturing problems. The photodiode having this defect is called a defective pixel.

[0007] The amount of charge output from one pixel in response to a predetermined light input is called a pixel value. A defective pixel is a pixel whose pixel value is shifted by ± several percent or more as compared with a normal pixel. In the video camera inspection process, the solid-state imaging device 20 having a defective pixel whose pixel value is shifted by ± 20% or more is discarded as a defective product. Therefore, defective pixels in the solid-state imaging device 20 that have passed the inspection process have pixel values of ± several% to ± 15%.
Most are off by%.

[0008] Some defective pixels always have a pixel value shifted by a predetermined value, and others have a shift in the pixel value. As time elapses, some pixels become defective pixels at a certain time and become normal pixels at another time.

A solid-state imaging device 2 used for a video camera
In the case of 0, those having hundreds of thousands of photodiodes (pixels) 21 are mainstream. It is extremely difficult to manufacture a solid-state imaging device 20 having no defective pixels.

Therefore, if the number of defective pixels is less than a predetermined number,
A method of recognizing this as a non-defective product and correcting a defective pixel by image signal processing is employed. This correction is performed according to the position information of the defective pixel stored in advance in a ROM or the like. However, since the number of pixels is extremely large, a large-capacity ROM is required, and management of position information is required, which increases costs.

[0011]

In a low-cost video camera, it is desired to correct a defective pixel without using the ROM. Defective pixels can be detected by image signal processing. For example, when the target pixel has an extremely large value or a small value compared to the surrounding pixels, it can be inferred that the target pixel is a defective pixel. Performing this defective pixel detection requires a memory for storing a two-dimensional image of a predetermined area centered on the target pixel, and requires a relatively long processing time.

In order to store the two-dimensional image, a frame memory or a plurality of line memories are required. If such a memory is used, the cost will increase even if the ROM for storing the position information of the defective pixel is deleted.

A video camera can capture a moving image of, for example, 30 frames / second. Defective pixel detection needs to process such video in real time,
The time for detecting a defective pixel must be short. 2 above
The process of storing a two-dimensional image in a memory and detecting a defective pixel has a long processing time, so that real-time processing is difficult.

An object of the present invention is to provide a pixel signal processing device capable of detecting a defective pixel with a small memory capacity.

Another object of the present invention is to provide a pixel signal processing device capable of detecting a defective pixel in a short time.

[0016]

According to one aspect of the present invention, a first photoelectric conversion element row in which a plurality of photoelectric conversion elements for generating pixel signals by photoelectric conversion are arranged, and a pixel signal is generated by photoelectric conversion. A photoelectric conversion element row in which a plurality of photoelectric conversion elements are arranged, and a second photoelectric conversion element row adjacent to the first photoelectric conversion element row and at least the first and second photoelectric conversion element rows are generated. Pixel signal including pixel signal is 1
A pixel signal output unit that transfers and outputs a row as an output row, and a target pixel signal in the one output row has a defect based on a pixel signal of one output row output by the pixel signal output unit. There is provided a pixel signal processing device including: a defect detection unit configured to detect whether a pixel signal is generated by a photoelectric conversion element.

The pixel signal output means outputs one output row including the pixel signals. The one output row includes pixel signals generated by the first photoelectric conversion element row and the second photoelectric conversion element row adjacent thereto. The defect detecting means can detect at high speed by detecting a defect based on the output row. Further, since the defect detection means performs detection based on the pixel signals generated by the first and second photoelectric conversion element rows, the defect detection means performs detection based on only the pixel signals generated by the first photoelectric conversion element row. , It is possible to perform highly accurate detection.

[0018]

FIG. 3 is a block diagram showing a configuration of a defective pixel correction device according to an embodiment of the present invention.

The solid-state image pickup device 1 has a large number of photodiodes arranged two-dimensionally, picks up a moving image of, for example, 30 frames / sec, and outputs an image signal IN. The defective pixel determination processing unit 2 determines whether each pixel in the image signal IN is a defective pixel. If the pixel is a defective pixel, the defective pixel correction processing unit 3 corrects the value of the defective pixel. The defective pixel determination processing unit 2 does not perform correction when the target pixel is not a defective pixel, and performs the above correction when the target pixel is a defective pixel, and outputs an image signal OUT. Image signal OU
T is output at, for example, 30 frames / second.

FIG. 1 is a plan view showing the structure of the solid-state imaging device 1. The solid-state imaging device 1 includes a plurality of photodiodes (photoelectric conversion elements) 1 arranged in a two-dimensional matrix.
One. The solid-state imaging device 1 has, for example, tens of thousands to hundreds of thousands of photodiodes 11, but for convenience of description,
In FIG. 1, the number of photodiodes 11 is reduced. The photodiode 11 is covered with any one of green, red and blue color filters, and can detect three color signals.

In the first row L1, red photodiodes (R1, R3,...) And blue photodiodes (B
, B4,...) Are alternately arranged in the horizontal direction. 2nd row L
2 has green photodiodes (G1, G2,...
・) Are arranged horizontally. Hereinafter, red is represented by R, blue is represented by B, and green is represented by G.

The odd rows are the first row L1, the third row L3, the fifth
A row L5 and a seventh row L7 are included. The even rows include a second row L2, a fourth row L4, a sixth row L6, and an eighth row L8. In odd rows, red photodiodes and blue photodiodes are alternately arranged. Green photodiodes are arranged in even rows. The green photodiode is vertically sandwiched between a red photodiode and a blue photodiode.

The photodiode 11 converts light received through the color filter into electric charges and stores the charges. The vertical charge transfer paths 12 are provided on both left and right sides of each column of the photodiodes 11.

The vertical charge transfer path 12 reads charges from the photodiode 11 and transfers the charges in the vertical direction (from top to bottom). Charges in the odd-row photodiodes (red and blue photodiodes) are read out to the right vertical charge transfer path 12. The charges in the photodiodes in the even rows (green photodiodes) are read out to the left vertical charge transfer path 12.

The channel position converter 13 supplies the charges received from the vertical charge transfer paths 12 to the horizontal charge transfer paths 14 such that the charges are located at substantially equal intervals in the horizontal direction on the horizontal charge transfer paths 14.

On the horizontal charge transfer path 14, pixel signals generated by the photodiodes 11 in the first row L1 and the second row L2 are set to G1, R1, G2, B2,.
Alternate in one row.

The horizontal charge transfer path 14 transfers the pixel signals G1, R1, G2, B2,... Of the first row L1 and the second row in the horizontal direction (from right to left). After that, the pixel signals of the third row L3 and the fourth row L4 are transferred, and then the fifth row L5
And the pixel signals in the sixth row L6 are transferred.
The pixel signals of the seventh and eighth rows L8 are transferred.

The output section 15 outputs a predetermined voltage according to the amount of charge of each pixel transferred from the horizontal charge transfer path 14. The output unit sequentially outputs the pixel signals of the first row L1 to the eighth row L8 in units of two rows.

In the solid-state imaging device 1, for example, two pixel signals G1 and R1 constitute one pixel, and two pixel signals G2 and B2 constitute another pixel. The first row L1 and the second row L2 constitute one pixel row, and the third row L3 and the fourth row L4 constitute another pixel row.

The solid-state imaging device 1 forms a square pixel.
That is, the horizontal pixel pitch Wh and the vertical pixel pitch Wv between the pixels are substantially the same. Both pixel pitch W
By making h and Wv the same, the horizontal and vertical resolutions can be made the same.

The horizontal pixel pitch Wh and the vertical pixel pitch Wv do not necessarily have to be the same. Further, the present invention is not limited to the case where two photodiodes 11 constitute one pixel, and one photodiode may constitute one pixel.

In this specification, a defective photodiode is called a defective pixel regardless of whether two photodiodes constitute one pixel or one photodiode constitutes one pixel. , The photodiode is called a pixel.

FIGS. 4A to 4C are diagrams for explaining a method of detecting a defective pixel. Defective pixel detection is performed in units of two rows, that is, a first row L1 and a second row L2, and the other rows are similarly performed in units of two rows. The above horizontal charge transfer path 14
FIG. 1 outputs a pixel signal in units of two rows. Defective pixel detection can be performed at high speed in real time by performing processing in units of two rows.

In the first column L1, the red pixel signals R1 and R1 of the first, third, fifth, seventh and ninth columns are provided every other pixel.
There are R3, R5, R7, R9. In the second column L2,
There are green pixel signals G1 to G9 in the first to ninth columns.

As shown in FIG. 4A, in the second row L2, the pixel signal G5 in the fifth column is significantly larger than the pixel signals G3, G4, G6, G7 of the surrounding four pixels. In this case, it can be suspected that the pixel (photodiode) of the pixel signal G5 may be a defective pixel.

However, in the first row L1, the pixel signals R5 in the fifth column are also the pixel signals R1, R3, R of the four surrounding pixels.
7, prominently larger than R9. When the pixel signal G5 is large and the pixel signal R5 is also large, it is considered that an image having a thin line in the vertical direction in the fifth column exists. In this case, it can be determined that the pixel signals G5 and R5 are not defective pixels.

As shown in FIG. 4B, the pixel signal G5 is significantly larger than the pixel signals G3, G4, G6, and G7 of the four surrounding pixels, but the pixel signal R5 is larger than the four surrounding pixels. If the signals are substantially equal to the signals R1, R3, R7, and R9, it can be determined that the pixel (photodiode) of the pixel signal G5 is a defective pixel.

As shown in FIG. 4C, the pixel signal R5 is much larger than the pixel signals R1, R3, R7, and R9 of the surrounding four pixels, but the pixel signal G5 is the pixel signal of the surrounding four pixels. If the signals G3, G4, G6, and G7 are substantially the same, it can be determined that the pixel (photodiode) of the pixel signal R5 is a defective pixel.

It should be noted that the pixel of the pixel signal can be determined to be a defective pixel not only when the pixel signal is prominently large but also when the pixel signal is prominently small.

In the case of a blue pixel signal, a defective pixel can be detected as in the case of a red pixel signal.

FIG. 5 is a flowchart showing processing for detecting a defective pixel of a green pixel and correcting the defective pixel. For example, the defect of the green pixel shown in FIG. 4B is detected.

In step SA1, the average value AV1 of the four green pixel signals G3, G4, G6 and G7 around the target pixel signal G5 is determined by the following equation.

AV1 = (G3 + G4 + G6 + G7) / 4 In step SA2, it is determined whether or not the equation (1) or (2) is satisfied. C1 is a constant, for example, 1 to 6, and 3 is preferable. Equation (1) means that the target pixel signal G5 is significantly larger than the average value AV1 of the surrounding pixel signals. Equation (2) means that the target pixel signal G5 is significantly smaller than the average value AV1 of the surrounding pixel signals.

G5 / AV1> C1 (1) G5 / AV1 <1 / C1 (2)

When both the equations (1) and (2) are not satisfied, it is determined that the pixel of the target pixel signal G5 is not a defective pixel, and the process is terminated. On the other hand, when Expression (1) or Expression (2) is satisfied, it is suspected that the pixel of the target pixel signal G5 may be a defective pixel. Check the pixel signal R5.

At step SA3, the average value AV2 of the four red pixel signals R1, R3, R7, R9 around the red pixel signal R5 is determined by the following equation.

AV2 = (R1 + R3 + R7 + R9) / 4 At step SA4, it is determined whether or not the equation (3) or (4) is satisfied. C2 is a constant, for example, 1 to 3, and preferably 1.5. Equation (3) means that the pixel signal R5 is significantly larger than the average value AV2 of the surrounding pixel signals, and Equation (4) is that the pixel signal R5 is larger than the average value AV2 of the surrounding pixel signals. Means small.

R5 / AV2> C2 (3) R5 / AV2 <1 / C2 (4)

When Expression (3) or Expression (4) is satisfied, a thin line exists in the vertical direction, it is determined that the pixel of the target pixel signal G5 is not a defective pixel, and the process ends (FIG. 4).
(A)). On the other hand, when both the equations (3) and (4) are not satisfied, it is determined that the pixel of the target pixel signal G5 is a defective pixel, and the process proceeds to step SA5 (see FIG. 4B).

At Step SA5, the pixel signal G5 of the defective pixel is corrected. For example, the average value of two green pixel signals G4 and G6 adjacent to the target pixel signal G5 is obtained by the following equation, and the average value is corrected as the value of the target pixel signal G5. Note that another correction method may be used. This is the end of the process.

G5 = (G4 + G6) / 2 Although the above description has been made for one target pixel signal G5, the same processing is performed for all green pixel signals.

FIG. 6 is a flowchart showing processing for detecting a defective pixel of a red pixel and correcting the defective pixel. For example, a defect of the red pixel shown in FIG.

In step SB1, the average value AV1 of the four red pixel signals R1, R3, R7, R9 around the target pixel signal R5 is determined by the following equation.

AV1 = (R1 + R3 + R7 + R9) / 4 In step SB2, it is determined whether or not the equation (5) or (6) is satisfied. C1 is a constant, for example, 1 to 6, and 3 is preferable. Equation (5) means that the target pixel signal R5 is significantly larger than the average value AV1 of the surrounding pixel signals. Equation (6) indicates that the target pixel signal R5 is larger than the average value AV1 of the surrounding pixel signals. It stands out and is small.

R5 / AV1> C1 (5) R5 / AV1 <1 / C1 (6)

When both the equations (5) and (6) are not satisfied, it is determined that the pixel of the target pixel signal R5 is not a defective pixel, and the process is terminated. On the other hand, when Expression (5) or Expression (6) is satisfied, it is suspected that the pixel of the target pixel signal R5 may be a defective pixel. Check the pixel signal G5.

In step SB3, the average value AV2 of the four green pixel signals G3, G4, G6 and G7 around the green pixel signal G5 is determined by the following equation.

AV2 = (G3 + G4 + G6 + G7) / 4 At step SB4, it is determined whether or not the equation (7) or (8) is satisfied. C2 is a constant, for example, 1 to 3, and 2 is preferable. Equation (7) means that the pixel signal G5 is significantly larger than the average value AV2 of the surrounding pixel signals, and Equation (8) is that the pixel signal G5 is larger than the average value AV2 of the surrounding pixel signals. Means small.

G5 / AV2> C2 (7) G5 / AV2 <1 / C2 (8)

When Expression (7) or Expression (8) is satisfied, a thin line exists in the vertical direction, it is determined that the pixel of the target pixel signal R5 is not a defective pixel, and the process ends (FIG. 4).
(A)). On the other hand, when both the expressions (7) and (8) are not satisfied, it is determined that the pixel of the target pixel signal R5 is a defective pixel, and the process proceeds to Step SB5 (see FIG. 4C).

At Step SB5, the pixel signal R5 of the defective pixel is corrected. The correction method will be described later with reference to FIG. 7. However, as in the case of the green pixel signal, the correction may be performed by an averaging process, or another correction method may be used. This is the end of the process.

Although the above description has been made with respect to one target pixel signal R5, similar processing is performed for all red pixel signals.

For the blue pixel signal, defective pixel detection and defective pixel correction are performed in the same manner as for the red pixel signal.

FIGS. 7A to 7E are diagrams showing a method of interpolating a red pixel signal. FIG. 7A shows part of the first row L1 and the second row L2. In the second row L2, five green pixel signals G3 to G7 in the third to seventh columns are arranged. First row L
1 includes red pixel signals R in the third, fifth, and seventh columns.
3, R5 and R7 are arranged every other pixel.

A method for interpolating the defective pixel signal R5 will be described. Hereinafter, the green, red, and blue signals that are the primary color signals are referred to as a G signal, an R signal, and a B signal.

First, the primary color signals R and G shown in FIG. 7A are converted into color difference signals Cr shown in FIG. 7B. That is,
The mapping from the primary color signal space to the color difference signal space is performed. Y-C
The b-Cr space and the RGB space have the following relationship. Here, the Y signal means a luminance signal.

Y = 0.3R + 0.59G + 0.11B (9) Cr = 0.7R−0.59G−0.11B (10) Cb = −0.3R−0.59G + 0.89B・ ・ (11)

Equation (10) can be approximated to equation (12), and equation (11) can be approximated to equation (13).

Cr ≒ RG (12) Cb ≒ BG (13)

Using equation (12), a Cr signal for each column in FIG. 7A is obtained. At this time, except for the defective pixel R5, only the normal pixel signals in the third and seventh columns are obtained by the following equation.

Cr3 = R3-G3 Cr7 = R7-G7

Next, the color difference signal Cr5 (FIG. 7C) of the defective pixel is obtained by interpolation based on the color difference signal (FIG. 7B). For example, the color difference signal Cr5 is obtained by the following linear interpolation.

Cr5 = (Cr3 + Cr7) / 2 Note that the interpolation method is not limited to the case where the interpolation is performed based on two adjacent pixels, and the interpolation may be performed based on the number of pixels larger or smaller. Further, the interpolation method is not limited to linear interpolation, and may be obtained by other weighted interpolation.

Next, the interpolated color difference signal Cr5 (FIG. 7)
(C)) is returned to the primary color signal R5 '(FIG. 7D). The primary color signal R5 'is obtained as follows using the above equation (12).

R5 '= Cr5 + G5 As shown in FIG. 7E, the first row L1 and the second
The pixel signal in the column L2 becomes the output signal OUT (FIG. 1).

By the above-mentioned interpolation, interpolation with little noise can be performed, and a decrease in resolution and generation of a false color (a color originally not present in the subject) can be suppressed.

The blue pixel signal can be interpolated in the same manner as the above-described red pixel signal.

FIG. 8 shows steps SA1 and SA2 in FIG.
11 is a flowchart showing another process in place of the process shown in FIG. FIG.
Is a graph for explaining the processing, in which the horizontal axis indicates a pixel position and the vertical axis indicates a pixel value.

At step SC1, the target pixel signal G5 and its surrounding four green pixel signals G3, G4, G6, G
7, it is determined whether or not the target pixel signal G5 is the maximum value or the minimum value.

When all of the expressions (14-1) to (14-4) are satisfied, it can be determined that the pixel signal G5 has the maximum value. When all of the expressions (15-1) to (15-4) are satisfied, it can be determined that the pixel signal G5 has the minimum value.

G5> G3 ... (14-1) G5> G4 ... (14-2) G5> G6 ... (14-3) G5> G7 ... (14-4) G5 <G3 (15-1) G5 <G4 (15-2) G5 <G6 (15-3) G5 <G7 (15-4)

When the condition of step SC1 is not satisfied, since the pixel signal G5 is neither the maximum value nor the minimum value, it is determined that the pixel signal G5 is not a defective pixel, and the process is terminated according to the arrow of No. If the condition of step SC1 is satisfied, the flow advances to step SC2 according to the arrow of Yes.

In step SC2, the maximum value of the four green pixel signals G3, G4, G6, G7 around the target pixel signal G5 is MAX, and the minimum value is MIN. For example, in FIG. 9, the pixel signal G6 is MAX, and the pixel signal G3 is MIN.

In step SC3, first, the maximum value MAX
And the average value AA of the minimum value MIN is calculated by the following equation.

AA = (MAX + MIN) / 2 Next, the absolute value A of the difference between the target pixel signal G5 and the average value AA
B is obtained by the following equation.

AB = | G5-AA | Next, the difference AC between the maximum value MAX and the minimum value MIN is obtained by the following equation.

AC = MAX-MIN In step SC4, it is determined whether or not Expression (16) is satisfied. Here, C3 is a constant. That is, the target pixel signal G5 is divided into four surrounding pixel signals G3, G4, G6, G
It is determined whether or not it is more than 7.

AB> C3 × AC (16)

If the expression (16) is not satisfied, it means that the pixel signal G5 does not protrude. Therefore, it is determined that the pixel signal G5 is not a defective pixel, and the process is terminated according to the arrow of No. On the other hand, when the expression (16) is satisfied, it means that the pixel signal G5 is protruding. Therefore, it is determined that the pixel signal G5 is a defective pixel, and the process proceeds to step SA3 in FIG.

Further, steps SA3 and SA4 in FIG.
Can also be replaced by the processing of steps SC1 to SC4 described above.

Further, the processing may be simplified by replacing steps SA3 and SA4 with only step SC1. That is, for the target pixel signal G5, step S
The process of C1 to SC4 is performed, and only the pixel signal R5 below it is determined whether it is the maximum value or the minimum value.
At this time, when it is determined that the pixel signal R5 is not the maximum value or the minimum value, it can be determined that the target pixel signal G5 is a defective pixel.

Similarly to the green pixel signal, the red pixel signal and the blue pixel signal are also processed in steps SC1 to SC
4 or step SC1 may be applied.

The above processing can be realized only by a relatively simple arithmetic unit including a comparator, an adder, and a bit shifter, so that high-speed processing becomes possible. Steps SA1 and SA2 are replaced with steps SC1 to SC4, and steps SA3 and SA4 are also replaced with steps SC1 to SC4.
When the above-described processing was replaced with an image of 320 × 240 pixels (CIF standard), real-time processing of 30 frames / sec was realized.

FIG. 10 is a diagram showing a bit map for storing the pixel positions of defective pixels. Solid-state imaging device 1
(FIG. 1) shows, for example, an image (320 × 24
0 pixels). When one pixel is composed of two photodiodes, the solid-state imaging device 1 has 3 photodiodes.
It has 20 × 240 × 2 photodiodes.

The bit map 31 is, for example, 640 × 24
It has 640 × 240 bits corresponding to 0 photodiodes. If the value of a bit is 0, it means that the photodiode corresponding to that bit is not a defective pixel. If the value of a bit is 1, it means that the photodiode corresponding to that bit is a defective pixel.

For example, during the initial 10 seconds, the above-described defective pixel detection is performed, and the value of the bit corresponding to the photodiode determined to be a defective pixel is set to 1. When it is determined that the same photodiode is a defective pixel for a predetermined number of times or more, the fact that the photodiode is defective is stored. Is corrected every time.

By performing the above processing, the result of the defective pixel detection can be learned, and the detection rate (recognition rate) of the defective pixel can be improved.

FIG. 11 is a plan view showing the structure of another solid-state imaging device. The solid-state imaging device 35 has a so-called Bayer array, and differs from the solid-state imaging device 1 (FIG. 1) only in the color arrangement. In odd columns, red pixels R and green pixels G are alternately arranged. In the even columns, blue pixels B and green pixels G are alternately arranged. The green pixel G is sandwiched between a red pixel R and a blue pixel B in the vertical direction. The output unit 15 outputs the pixel signals of the first row L1 and the second row L2 in the order of G1, R1, B2, G2,.

FIG. 12 shows a first example of the solid-state imaging device 35.
It is a figure showing a part of row L1 and the 2nd row L2.

A method for determining whether the pixel signal G5 or the pixel signal R5 is a defective pixel will be described. Pixel signal G5
And four green pixel signals G1, G3, G7,
Using G9, it is determined whether or not the pixel signal G5 protrudes from surrounding pixel signals by the same method as described above. Then, by using the pixel signal R5 and the four red pixel signals R1, R3, R7, and R9 around the pixel signal R5, the pixel signal R5
Is determined by a method similar to the above as to whether or not is protruding from the surrounding pixel signals.

By judging whether or not the pixel signal G5 or R5 protrudes, it is possible to detect a defective pixel of the pixel signal G5 or R5. Defective pixel detection can be similarly performed for the blue pixel signal.

According to the present embodiment, the solid-state imaging device can output pixel signals generated by the photodiodes for two rows as one row. By performing defective pixel detection using the pixel signals of the two rows, high-speed defective pixel detection becomes possible, and real-time processing of a moving image can be performed.

Since defective pixel detection can be performed in a short time, defective pixel detection can be performed for each frame of a moving image. In this case, a memory for storing the position information of the defective pixel in advance becomes unnecessary.

Since defective pixel detection is performed based on the pixel signals of two rows, a frame memory and a line memory for storing other rows are not required. By reducing the memory capacity, the cost can be reduced and the defective pixel detection device can be downsized.

Some of the defective pixels may not show the symptoms of the defective pixel over time. For such a defective pixel, it is not preferable to fix the position information of the defective pixel and record it in advance. In this case, if the defective pixel is detected for each frame without storing the position information of the defective pixel, the defective pixel having the above-mentioned symptom can be detected.

In this embodiment, four pixels around the target pixel are used.
The case where processing is performed using pixels has been described, but the number of pixels is not limited to four.

The solid-state image pickup device is not limited to a single plate type, but may be a two-plate type or a three-plate type. The single-plate type is a type in which three color filters are formed on one substrate as shown in FIG. The three-plate type is a type in which a single-color filter is formed on each of three substrates. Further, the present invention is not limited to a color image but can be applied to a black and white image. That is, the solid-state imaging device does not need to be provided with a color filter.

Although the case where the solid-state imaging device outputs data in units of two rows has been described, output may be performed in units of three or more lines.

Although the present invention has been described in connection with the preferred embodiments,
The present invention is not limited to these. For example, it will be apparent to those skilled in the art that various modifications, improvements, combinations, and the like can be made.

[0110]

As described above, according to the present invention,
One row output by the pixel signal output means includes a pixel signal generated by a first photoelectric conversion element row and a second photoelectric conversion element row adjacent thereto. The defect detection means can detect at high speed by detecting a defect based on the one row. Further, since the defect detection unit performs detection based on the pixel signals generated by the first and second photoelectric conversion element rows, the defect detection unit performs detection based on only the pixel signals generated by the first photoelectric conversion element row. , It is possible to perform highly accurate detection.

Since defects can be detected at high speed,
Real-time processing of video becomes possible. That is, a defect can be detected in real time for each frame image of a moving image.

Further, since the moving image can be processed in real time, a memory for storing the position information of the defective pixel in advance becomes unnecessary.

[Brief description of the drawings]

FIG. 1 is a plan view of a solid-state imaging device according to an embodiment of the present invention.

FIG. 2 is a plan view of a conventional solid-state imaging device.

FIG. 3 is a block diagram illustrating a configuration of a defective pixel correction device.

FIG. 4A shows a case where there is no defective pixel;
(B) and (C) are diagrams showing a case where there is a defective pixel.

FIG. 5 is a flowchart showing defective pixel detection processing and defective pixel correction processing for a green pixel.

FIG. 6 is a flowchart showing defective pixel detection processing and defective pixel correction processing for a red pixel.

FIGS. 7A to 7E are diagrams showing a method of correcting a red defective pixel.

FIG. 8 is a flowchart of a process that replaces steps SA1 and SA2 in FIG. 5;

FIG. 9 is a graph showing a relationship between a pixel position and a pixel value.

FIG. 10 is a diagram showing a bitmap for recording a defective pixel.

FIG. 11 is a plan view of another solid-state imaging device.

12 is a plan view showing a part of the solid-state imaging device shown in FIG.

[Explanation of symbols]

 1,20,35 solid-state imaging device 2 defective pixel determination processing unit 3 defective pixel correction processing unit 11,21 photodiode 12,22 vertical charge transfer path 13 channel position conversion unit 14,24 horizontal charge transfer path 15,25 output unit 31 bitmap

Claims (2)

[Claims] 1. A first photoelectric conversion element row in which a plurality of photoelectric conversion elements that generate pixel signals by photoelectric conversion are arranged, and a photoelectric conversion element row in which a plurality of photoelectric conversion elements that generate pixel signals by photoelectric conversion are arranged. A second photoelectric conversion element row adjacent to the first photoelectric conversion element row; and a pixel signal including at least a pixel signal generated by the first and second photoelectric conversion element rows as one output row. A pixel signal output unit for transferring and outputting, and a photoelectric conversion element having a defect in a target pixel signal in the one output row is generated based on a pixel signal of one output row output by the pixel signal output unit. And a defect detecting means for detecting whether the pixel signal is a detected pixel signal. 2. An interpolating means for interpolating a pixel signal generated by a photoelectric conversion element having a defect detected by the defect detecting means on the basis of a pixel signal of one output row output by the pixel signal outputting means. The pixel signal processing device according to claim 1, further comprising: