Low-noise reading circuit for CMOS image sensor and reading method thereof

Abstract

The invention discloses a low-noise reading circuit for a CMOS image sensor and a reading method thereof. The reading circuit comprises a signal multiple-sampling module, a signal integration module and a signal averaging module. Two ends of the signal integration module are connected with the signal multiple-sampling module and the signal averaging module. The other end of the signal integration module is a signal input end. The other end of the signal averaging module is a signal output end. The signal multiple-sampling module carries out multiple-sampling processing on to-be-processed signals and transmits the signals to the signal integration module for integration summation; the integration summation signals are transmitted to the signal averaging module for averaging; and an average signal is output through the signal output end. According to the low-noise reading circuit for the CMOS image sensor provided by the invention, the PIXEL equivalent input noises can be effectively reduced, the low-noise reading circuit is particularly applicable to a low light environment; the image quality can be effectively improved; and the low-noise reading circuit is suitable for popularized usage.

Description

technical field [0001] The invention relates to the field of image sensors, in particular to a low-noise readout circuit of a CMOS image sensor and a readout method thereof. Background technique [0002] In the field of image sensors, improving image quality is an eternal theme. The photosensitive signal of the image sensor will be affected by various noise sources during transmission, making it difficult to improve the signal-to-noise ratio. Noise can cause various FPN (solid state noise) and various random bright or dark spots in the image. Especially in low-light conditions, because the photogenerated current is relatively small, the signal is easily submerged in noise, and the image quality is particularly poor in low-light environments. [0003] The method used for noise processing in the prior art is CDS technology, that is, correlated double sampling technology. This method is widely used in the field of CMOS image sensors. This technology can reduce the FPN of the ...

AI Technical Summary

Problems solved by technology

Especially in low-light conditions, due to the relatively small photo-generated current, the signal is easily submerged in noise, and the image quality is particularly poor in low-light environments.

[0003] The method used for noise processing in the prior art is CDS technology, that is, correlated double sampling technology. This method is widely used in the field of CMOS image sensors. This technology can reduce the FPN of the pixel unit and the noise of the source follower. The effect is limited in the environment, and the image quality problem in the low-light environment cannot be improved.

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