Simulation image signal processing method for CMOS imaging sensor and circuit thereof

Abstract

The invention discloses a CMOS image sensor analog image signal processing method and its circuit. The pixel matrix is ​​divided into two symmetrical channels of odd and even columns of pixels, and through corresponding timing control, the correlation double sampling of each pixel signal is carried out. The positive and negative half cycles of the column clock are directly sent to the corresponding two-way symmetrical and only composed of one-stage switched capacitor differential operation amplifier circuits to perform subtraction in the odd and even column pixel analog image signal processing circuits respectively. Completely eliminate the dynamic noise and circuit fixed mode noise generated by the sampling circuit in different columns and the device difference of the column driving circuit, and can realize color gain control, exposure gain control and dark light background control, and the dark light background control is not affected by exposure Effect of gain control. On the premise of ensuring the imaging effect, the method and the circuit of the invention simplify the circuit structure, reduce the area of ​​the CMOS image sensor chip, reduce the manufacturing cost, and are beneficial to the miniaturization of the final product.

Description

technical field [0001] The invention relates to general image data processing, in particular to an analog image signal processing method and circuit of a CMOS image sensor which occupies a dominant position in low-end image and video information products. Background technique [0002] A signal processing circuit of an existing Complementary Metal-Oxide-Semiconductor Transistor Image Sensor (CMOS image sensor for short) includes a front-end analog image signal processing circuit and a back-end digital image signal processing circuit. The front-end analog image signal processing circuit includes a correlated double sampling (Correlate Doubled Sampling, referred to as CDS) circuit that can eliminate circuit fixed pattern noise (Fixed Pattern Noise, referred to as FPN), a color gain control circuit, an exposure control circuit and a dark background control circuit; The back-end digital image signal processing circuit includes an analog-to-digital converter and a digital image si...

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Problems solved by technology

The front-end image signal processing circuit of the existing CMOS image sensor uses multiple circuit modules or multi-level circuits to provide red, green 1 color, green 2 colors, and blue (referred to as R, G1, G2, B) signals to the pixel matrix respectively. For exposure gain control, color gain control and dark light background control, the processing circuit has a single function and complex circuit, which increases the chip area, increases the manufacturing cost, and restricts the miniaturization of the product. The FPN noise caused by the difference of stage circuit devices

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