# US 2009/0021606 A1 · Image pickup apparatus, image processing method, and computer program

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- Number: US 2009/0021606 A1
- Document ID: US20090021606A1
- Status: Published application
- Kind: A1
- Application number: 12/145,926
- Filed: 2008-06-25
- Published: 2009-01-22
- Earliest claimed: 2007-07-17
- Assignees: Sony Corporation
- Inventors: Daisuke KURUMA; Nobuyuki Sato
- Web page: https://patentgrep.com/patent/US20090021606A1

## CPC

- H04N 25/672: between adjacent sensors or output registers for reading a single image
- H04N 23/80: Camera processing pipelines; Components thereof
- H04N 25/633: by using optical black pixels
- H04N 25/68: applied to defects
- H04N: PICTORIAL COMMUNICATION, e.g. TELEVISION

## Abstract

An image pickup apparatus includes an image pickup device including a plurality of imaging planes each having different dark current characteristics, and an image processing unit for receiving a signal from the image pickup device and performing an image generating process. The image processing unit calculates a dark current estimated to be generated in each of the plurality of imaging planes, independently for each imaging plane, and performs a dark current eliminating process on the basis of a dark current value calculated for each imaging plane.

## Claims

### Claim 1

An image pickup apparatus comprising:
an image pickup device including a plurality of imaging planes each having different dark current characteristics; and
an image processing unit for receiving a signal from the image pickup device and performing an image generating process,
wherein the image processing unit calculates a dark current estimated to be generated in each of the plurality of imaging planes, independently for each imaging plane, and performs a dark current eliminating process on the basis of a dark current value calculated for each imaging plane.

### Claim 2 (depends on 1)

The image pickup apparatus according to claim 1, wherein:
the image pickup device is manufactured by a divisional exposure process and includes the plurality of imaging planes each corresponding to each exposure area unit; and
the image processing unit calculates independently for each imaging plane a dark current estimated to be generated in each of the plurality of imaging planes corresponding to each exposure area unit, and performs the dark current eliminating process on the basis of a dark current value calculated for each imaging plane.

### Claim 3 (depends on 1)

The image pickup apparatus according to claim 1, wherein:
the image pickup device comprises;
an effective image area for acquiring photographed image data,
an optical black (OPB) area having lines corresponding to respective lines constituting the effective image area, respectively in each of the plurality of imaging planes each having different dark current characteristics, and
the image processing unit calculates a dark current value of the effective image area in each imaging plane by using as a reference value a dark current measured in the OPB area set to the same imaging plane, and performs the dark current eliminating process for the effective image area of each imaging plane by using the calculation result.

### Claim 4 (depends on 3)

The image pickup apparatus according to claim 3, further comprising:
a storage unit storing a dark current data table for recording data including difference data based upon dark current measurement values between the effective image area in upper and lower areas in each imaging plane having different dark current characteristics and the OPB area,
wherein the image processing unit performs the dark current eliminating process for the effective image area of each imaging plane, by referring to the data recorded in the dark current data table.

### Claim 5 (depends on 4)

The image pickup apparatus according to claim 4, wherein:
the dark current data table is a table for recording a plurality of data sets based on measurement values obtained under a plurality of photographing conditions changing at least either a shutter speed of a temperature; and
the image processing unit selects a data set having conditions approximate to conditions during photographing from a plurality of data sets recorded in the dark current data table, on the basis of shutter speed or temperature information during photographing, and performs the dark current eliminating process for the effective image area in each imaging plane by referring to the selected data set.

### Claim 6 (depends on 3)

The image pickup apparatus according to claim 3, wherein:
the image pickup device is constructed of CMOS; and
the image processing unit reads signals from the image pickup device composed of CMOS line-sequentially from an upper line to a lower line, on an assumption that a dark current contained in a read signal increases in proportion to transfer from an upper area to a lower area of the image pickup device, calculates a dark current value of the effective image area in each imaging plane, by using, as a reference value, a dark current measured in the OPB area set to the same imaging plane, and performs the dark current eliminating process for the effective image area in each imaging plane by using a calculation result.

### Claim 7 (depends on 6)

The image pickup apparatus according to claim 6, wherein the image processing unit reads signals from the image pickup device composed of CMOS line-sequentially from an upper line to a lower line, calculates a dark current contained in signals corresponding to each line of the effective image area from which the signals are read, by using a dark current value of the OPB area at the same line or a line one line before as a reference value, and performs the dark current eliminating process for the effective image area in each imaging plane by using a calculation result.

### Claim 8 (depends on 7)

The image pickup apparatus according to claim 7, wherein the image processing unit acquires a dark current value of the OPB area at each line by utilizing a measurement result by an integrator adopting an infinite impulse response (IIR) filter.

### Claim 9 (depends on 1)

The image pickup apparatus according to claim 1, wherein:
the image pickup device includes;
an effective image area for acquiring photographed image data, formed in each of the plurality of imaging planes each having different dark current characteristics;
an H-optical black (HOPB) area having lines corresponding to respective lines constituting the effective image area, at least in a same imaging plane as each of the plurality of imaging planes; and
a V-optical black (VOPB) area set to an area containing each of the plurality of imaging planes; and
the image processing unit divides the VOPB area into areas corresponding to each of the plurality of imaging planes, measured a dark current of each divided VOPB area, and performs the dark current a dark current eliminating process for the effective image area of each imaging plane, by adopting dark current values corresponding to the plurality of VOPB areas corresponding to the plurality of imaging planes and a dark current value measured in the at least one HOPB area.

### Claim 10 (depends on 9)

The image pickup apparatus according to claim 9, further comprising:
a storage unit storing a dark current data table for recording data including difference data based upon dark current measurement values between the effective image area in upper and lower areas in each imaging plane having different dark current characteristics and the HOPB area,
wherein the image processing unit performs the dark current eliminating process for the effective image area of each imaging plane, by referring to the data recorded in the dark current data table.

### Claim 11 (depends on 10)

The image pickup apparatus according to claim 10, wherein:
the dark current data table is a table for recording a plurality of data sets based on measurement values obtained under a plurality of photographing conditions changing at least either a shutter speed or a temperature; and
the image processing unit selects a data set having conditions approximate to conditions during photographing from a plurality of data sets recorded in the dark current data table, on the basis of shutter speed or temperature information during photographing, and performs the dark current eliminating process for the effective image area in each imaging plane by referring to the selected data set.

### Claim 12 (depends on 3)

The image pickup apparatus according to claim 3, wherein:
the image pickup device is composed of CMOS; and
the image processing unit reads signals from the image pickup device composed of CMOS line-sequentially from an upper line to a lower line, on an assumption that a dark current contained in a read signal increases in proportion to transfer from an upper area to a lower area of the image pickup device, calculates a dark current value of the effective image area in each imaging plane, by using a dark current measured in the HOPB area set to the same imaging plane as a reference value, and performs the dark current eliminating process for the effective image area in each imaging plane by using a calculation result.

### Claim 13 (depends on 12)

The image pickup apparatus according to claim 12, wherein the image processing unit reads signals from the image pickup device composed of CMOS line-sequentially from an upper line to a lower line, calculates a dark current contained in signals corresponding to each line of the effective image area from which the signals are read, by using a dark current value of the HOPB area at the same line or a line one line before as a reference value, and performs the dark current eliminating process for the effective image area in each imaging plane by using a calculation result.

### Claim 14 (depends on 7)

The image pickup apparatus according to claim 7, wherein the image processing unit is configured to obtain a dark current value of the OPB area at each line by utilizing a measurement result by an integrator adopting an infinite impulse response (IIR) filter.

### Claim 15

An image processing method to be performed by an image processing apparatus, the method comprising:
in an image processing unit,
an image processing step of receiving a signal acquired by an image pickup device including a plurality of imaging planes each having different dark current characteristics;
wherein the image processing step calculates a dark current estimated to be generated in each of the plurality of imaging planes, independently for each imaging plane, and performs a dark current eliminating process on the basis of a dark current value calculated for each imaging plane.

### Claim 16 (depends on 15)

The image processing method according to claim 15, wherein:
the image pickup device is manufactured by a divisional exposure process and includes the plurality of imaging planes each corresponding to each exposure area unit; and
the image processing step calculates independently for each imaging plane a dark current estimated to be generated in each of the plurality of imaging planes corresponding to each exposure area unit, and performs the dark current eliminating process on the basis of a dark current value calculated for each imaging plane.

### Claim 17 (depends on 15)

The image processing method according to claim 15, wherein:
the image pickup device comprises;
an effective image area for acquiring photographed image data;
an optical black (OPB) area having lines corresponding to respective lines constituting the effective image area, respectively in each of the plurality of imaging planes each having different dark current characteristics; and
the image processing step calculates a dark current value of the effective image area in each imaging plane by using as a reference value a dark current measured in the OPB area set to the same imaging plane, and performs the dark current eliminating process for the effective image area of each imaging plane by using the calculation result.

### Claim 18 (depends on 17)

The image processing method according to claim 17, wherein:
the image processing apparatus includes a storage unit storing a dark current data table for recording data including difference data based upon dark current measurement values between the effective image area in upper and lower areas in each imaging plane having different dark current characteristics and the OPB area,
wherein the image processing step performs the dark current eliminating process for the effective image area of each imaging plane, by referring to the data recorded in the dark current data table.

### Claim 19 (depends on 18)

The image processing method according to claim 18, wherein:
the dark current data table is a table for recording a plurality of data sets based on measurement values obtained under a plurality of photographing conditions changing at least either a shutter speed or a temperature; and
the image processing step selects a data set having conditions approximate to conditions during photographing from a plurality of data sets recorded in the dark current data table, on the basis of shutter speed or temperature information during photographing, and performs the dark current eliminating process for the effective image area in each imaging plane by referring to the selected data set.

### Claim 20 (depends on 17)

The image processing method according to claim 17, wherein:
the image pickup device is composed of CMOS; and
the image processing step reads signals from the image pickup device composed of CMOS line-sequentially from an upper line to a lower line, on an assumption that a dark current contained in a read signal increases in proportion to transfer from an upper area to a lower area of the image pickup device, calculates a dark current value of the effective image area in each imaging plane, by using as a reference value a dark current measured in the OPB area set to the same imaging plane, and performs the dark current eliminating process for the effective image area in each imaging plane by using a calculation result.

### Claim 21 (depends on 20)

The image processing method according to claim 20, wherein the image processing unit reads signals from the image pickup device composed of CMOS line-sequentially from an upper line to a lower line, calculates a dark current contained in signals corresponding to each line of the effective image area from which the signals are read, by using a dark current value of the OPB area at the same line or a line one line before as a reference value, and performs the dark current eliminating process for the effective image area in each imaging plane by using a calculation result.

### Claim 22 (depends on 21)

The image processing method according to claim 21, wherein the image processing step acquires a dark current value of the OPB area at each line by utilizing a measurement result by an integrator adopting an infinite impulse response (IIR) filter.

### Claim 23 (depends on 15)

The image processing method according to claim 15, wherein:
the image pickup device comprises;
an effective image area for acquiring photographed image data, formed in each of the plurality of imaging planes each having different dark current characteristics;
an H-optical black (HOPB) area having lines corresponding to respective lines constituting the effective image area, at least in a same imaging plane as each of the plurality of imaging planes; and
a V-optical black (VOPB) area set to an area containing each of the plurality of imaging planes; and
the image processing step divides the VOPB area into areas corresponding to each of the plurality of imaging planes, measured a dark current of each divided VOPB area, and by adopting dark current values corresponding to the plurality of VOPB areas corresponding to the plurality of imaging planes and a dark current value measured in the at least one HOPB area, performs the dark current a dark current eliminating process for the effective image area of each imaging plane.

### Claim 24 (depends on 23)

The image processing method according to claim 23, wherein:
the image processing apparatus includes a storage unit storing a dark current data table for recording data including difference data based upon dark current measurement values between the effective image area in upper and lower areas in each imaging plane having different dark current characteristics and the HOPB area,
wherein the image processing step performs the dark current eliminating process for the effective image area of each imaging plane, by referring to the data recorded in the dark current data table.

### Claim 25 (depends on 24)

The image processing method according to claim 24, wherein:
the dark current data table is a table for recording a plurality of data sets based on measurement values obtained under a plurality of photographing conditions changing at least either a shutter speed or a temperature; and
the image processing step selects a data set having conditions approximate to conditions during photographing from a plurality of data sets recorded in the dark current data table, on the basis of shutter speed or temperature information during photographing, and performs the dark current eliminating process for the effective image area in each imaging plane by referring to the selected data set.

### Claim 26 (depends on 13)

The image processing method according to claim 13, wherein:
the image pickup device is composed of CMOS; and
the image processing step reads signals from the image pickup device composed of CMOS line-sequentially from an upper line to a lower line, on an assumption that a dark current contained in a read signal increases in proportion to transfer from an upper area to a lower area of the image pickup device, calculates a dark current value of the effective image area in each imaging plane, by using a dark current measured in the HOPB area set to the same imaging plane as a reference value, and performs the dark current eliminating process for the effective image area in each imaging plane by using a calculation result.

### Claim 27 (depends on 26)

The image processing method according to claim 26, wherein the image processing step reads signals from the image pickup device composed of CMOS line-sequentially from an upper line to a lower line, calculates a dark current contained in signals corresponding to each line of the effective image area from which the signals are read, by using a dark current value of the HOPB area at the same line or a line one line before as a reference value, and performs the dark current eliminating process for the effective image area in each imaging plane by using a calculation result.

### Claim 28 (depends on 27)

The image processing method according to claim 27, wherein the image processing step acquired a dark current value of the OPB area at each line by utilizing a measurement result by an integrator adopting an infinite impulse response (IIR) filter.

### Claim 29

A computer program for making an image processing apparatus execute a process, the process comprising:
an image processing step of performing an image generating process by inputting a signal acquired by an image pickup device including a plurality of imaging planes each having different dark current characteristics, to an image processing unit;
wherein the image processing step calculates a dark current estimated to be generated in each of the plurality of imaging planes, independently for each imaging plane, and performs a dark current eliminating process on the basis of a dark current value calculated for each imaging plane.