Dynamic expansion method applied to CMOS image sensor

Abstract

The invention discloses a dynamic expansion method applied to a CMOS image sensor, and the CMOS image sensor employs a double-gain pixel circuit, and enables the double-gain pixel circuit to be in a high-gain mode through a pixel control time sequence. The CMOS image sensor carries out exposure in an internal exposure mode, after preset exposure time is reached, exposure is finished, a pixel signal is read, and then the number of saturated pixels in a frame and the maximum unsaturated voltage value are counted; and the exposure time of the next frame is determined according to the number of the saturated pixels or the maximum unsaturated voltage amplitude, and a corresponding control time sequence is generated to start exposure of the next frame. According to the invention, pixel sequential control and internal exposure control are combined, so that the imaging effect in a low-light environment is good; high-gain output of pixels is maintained, and the detection sensitivity is improved; the dynamic range of image signals is improved, and automatic adjustment of exposure time is realized through internal exposure time control.

Description

technical field [0001] The invention relates to the field of CMOS image sensors, in particular to a dynamic expansion method applied to CMOS image sensors. Background technique [0002] The current image acquisition and processing applications are more and more widely used, and the image sensor is the core component. Since the application of the CCD chip is more complicated, as the CMOS image sensor technology becomes more mature, the performance is getting better and better, making the application range of the CMOS image sensor more and more wider. Although CMOS image sensors have many advantages that CCD chips cannot match, they are inferior to CCD image sensors in terms of imaging quality (signal-to-noise ratio and dynamic range, etc.), especially in low-light and low-light environments. Therefore, CMOS imaging applications are limited in many occasions, and it is necessary to provide a method for improving the image quality of CMOS image sensors so that they can be deve...

AI Technical Summary

Problems solved by technology

Although CMOS image sensors have many advantages that CCD chips cannot match, they are inferior to CCD image sensors in terms of imaging quality (signal-to-noise ratio and dynamic range, etc.), especially in low-light and low-light environments.

Therefore, the application of CMOS imaging is limited in many occasions, and it is necessary to provide a method for improving the image quality of CMOS image sensors so that they can be developed and applied in low-light and low-light environments.

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