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Mean noise reduction rapid processing circuit and method suitable for image sensor

An image sensor and processing circuit technology, applied in the field of image sensors, can solve problems such as motion afterimages, time difference, and time growth, and achieve the effects of improving image quality, reducing frame selection, and fast processing

Active Publication Date: 2022-04-22
四川创安微电子有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0004] The technical problem to be solved by the present invention is aimed at the shot noise generated by dark current and random photo-generated electrons in the photoelectric imaging device of the image sensor. The average value of the gray values ​​of multiple images is obtained in the processor ISP to reduce noise. This processing method will cause multiple selection and reading of each row of pixels, and the time to process an image will increase by an equal factor; and when shooting at high speed When there is a moving object, there is a time difference in acquiring multiple frames of images, so there may be motion afterimages

Method used

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  • Mean noise reduction rapid processing circuit and method suitable for image sensor

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Embodiment 1

[0060] Such as Figure 1 to Figure 8 As shown, the present invention is suitable for an average noise reduction fast processing circuit of an image sensor, comprising a CDS operation circuit for controllable addition and subtraction, the input end of the CDS operation circuit for controllable addition and subtraction is connected to an ADC conversion circuit, The first output end of the CDS operation circuit of the controllable addition and subtraction is connected to the input end of the CDS operation circuit of the controllable addition and subtraction, and the second output end of the CDS operation circuit of the controllable addition and subtraction is connected to the to the ISP image signal processor;

[0061] The CDS operation circuit of the controllable addition and subtraction method is used to realize the form of cyclic addition and subtraction operation combination to realize the sum of multiple sampling CDS voltage differences when a frame of image pixels is read o...

Embodiment 2

[0096] Such as Figure 1 to Figure 8 As shown, the difference between this embodiment and Embodiment 1 is that this embodiment provides a fast processing method for mean value noise reduction suitable for image sensors, such as image 3 As shown, the method includes:

[0097] Use the image sensor for frame selection to obtain a frame of image;

[0098] Line selection is carried out from a frame of image acquired, and for a line of pixels, the controllable addition and subtraction CDS operation circuit is used to realize the form of cyclic addition and subtraction operation combination, so that multiple sampling CDS voltages can be obtained when the same line of pixels is read out The sum of differences; wherein, the CDS operation circuit of the controllable addition and subtraction adopts a fast processing circuit for mean value noise reduction suitable for image sensors described in Embodiment 1;

[0099] According to the obtained sum of multiple sampling CDS voltage differ...

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Abstract

The invention discloses a mean noise reduction rapid processing circuit and method suitable for an image sensor, and the circuit comprises a CDS operation circuit capable of controlling the addition and subtraction, and the input end of the CDS operation circuit capable of controlling the addition and subtraction is connected with an ADC conversion circuit. The first output end of the CDS operational circuit capable of controlling addition and subtraction is connected with the input end of the CDS operational circuit capable of controlling addition and subtraction, and the second output end of the CDS operational circuit capable of controlling addition and subtraction is connected to an ISP image signal processor; the CDS operation circuit capable of controlling addition and subtraction is used for obtaining the sum of multiple sampling CDS voltage difference values when one frame of image pixel is read out in a cyclic addition and subtraction operation combination mode. According to the invention, an average value can be obtained when pixels of a frame of image are read out, so that the time for signal transmission and image processing is greatly reduced; and the pixels in the same row are sampled for multiple times for calculation, and the sampling time interval is very short, so that ghosting cannot be caused.

Description

technical field [0001] The invention relates to the technical field of image sensors, in particular to a mean value noise reduction fast processing circuit and method suitable for image sensors. Background technique [0002] Shot noise is caused by the discrete characteristics of the electron itself, mainly generated by dark current and random photo-generated electrons, and the probability of particle emission within a certain time interval obeys the Poisson distribution. For the Poisson distribution, the mean is the same as the variance. [0003] With people's demand for image quality and night scene mode, especially night scene mode, under low light conditions, because the brightness is too low, a large amount of dark current and random noise will be mixed in; For the shot noise generated by electrons, the existing technology is to use the multi-frame image CDS (Correlated Double Sampling) conversion to take the average value of the overall gray value of the image in the ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H04N5/361H04N5/359
CPCH04N25/626H04N25/63Y02D10/00
Inventor 不公告发明人
Owner 四川创安微电子有限公司
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