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US 8,537,254 B2Granted
Image signal processing device and solid-state imaging device
AssigneeKabushiki Kaisha Toshiba
InventorsYuji Miyashita, Junichi Hosokawa, Masahiko Nozaki
Life of this patent
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Abstract
According to the embodiment, a feedback clamp circuit is included, which increases or decreases a clamp parameter so that a black level approaches a target value while controlling a change amount of the clamp parameter, which sets the black level, based on the black level read out from OB pixels.
Claims19
An image signal processing device comprising:
- a feedback clamp circuit that increases or decreases a clamp parameter so that a black level approaches a target value while controlling a change amount of the clamp parameter, which sets the black level, based on the black level read out from OB pixels;
- an OB clamp circuit that clamps an image signal read out from effective pixels and calculates a clamp parameter correction coefficient that controls the change amount of the clamp parameter based on the black level read out from the OB pixels;
- a gain adjustment circuit that adjusts white balance and gain of an image signal output from the clamp circuit;
- a color separation circuit that converts an image signal output from the gain adjustment circuit into a color separation signal;
- and
- an automatic level control circuit that adjusts a digital gain and an analog gain based on a luminance signal extracted in the color separation circuit, and outputs the digital gain to the gain adjustment circuit and outputs the analog gain to the feedback clamp circuit.
3 more elements
A solid-state imaging device comprising:
- a CMOS sensor that outputs an image signal;
- and
- an image signal processing unit that processes the image signal read out from the CMOS sensor, wherein
- the CMOS sensor includes
- an effective pixel unit in which effective pixels are arrayed,
- an OB pixel unit in which OB pixels are arrayed,
- a column ADC circuit that digitalizes a signal component read out from the effective pixels based on a comparison result with a reference voltage, and
- a reference voltage generating unit that generates the reference voltage, and the image signal processing unit includes
- a feedback clamp circuit that increases or decreases a clamp parameter that sets a black level so that the black level approaches a target value while controlling a change amount of the clamp parameter based on the black level read out from the OB pixels, and
- an OB clamp circuit that clamps an image signal read out from the effective pixels and calculates a clamp parameter correction coefficient that controls the change amount of the clamp parameter based on the black level read out from the OB pixels,
- wherein
- the OB pixel unit includes
- an FBC pixel unit in which OB pixels that generate a black level used for calculating the clamp parameter correction coefficient are provided, and
- an HOB pixel unit in which OB pixels that generate a black level used for clamping the image signal are provided.
11 more elements
A solid-state imaging device comprising:
- a CMOS sensor that outputs an image signal;
- and
- an image signal processing unit that processes the image signal read out from the CMOS sensor, wherein
- the CMOS sensor includes
- an effective pixel unit in which effective pixels are arrayed,
- an OB pixel unit in which OB pixels are arrayed,
- a column ADC circuit that digitalizes a signal component read out from the effective pixels based on a comparison result with a reference voltage, and
- a reference voltage generating unit that generates the reference voltage, and the image signal processing unit includes
- a feedback clamp circuit that increases or decreases a clamp parameter that sets a black level so that the black level approaches a target value while controlling a change amount of the clamp parameter based on the black level read out from the OB pixels, and
- an OB clamp circuit that clamps an image signal read out from the effective pixels and calculates a clamp parameter correction coefficient that controls the change amount of the clamp parameter based on the black level read out from the OB pixels, and
- the solid-state imaging device further comprising:
- a gain adjustment circuit that adjusts white balance and gain of an image signal output from the OB clamp circuit;
- a color separation circuit that converts an image signal output from the gain adjustment circuit into a color separation signal;
- and
- an automatic level control circuit that adjusts a digital gain and an analog gain based on a luminance signal extracted in the color separation circuit, and outputs the digital gain to the gain adjustment circuit and outputs the analog gain to the feedback clamp circuit.
12 more elements
Dependencies are inferred from the claim text.