Algorithm and system for dark level correction of cmos image sensor

Abstract

The invention discloses an algorithm used for black level correction of a CMOS (Complementary Metal Oxide Semiconductor) image sensor and a system thereof. The algorithm comprises the following steps that S1, a background system configures an upper limit of a black level and an output data offset; S2, the background system inputs an image provided with a black level message line; S3, the background system utilizes a median filtering algorithm to correct a defect pixel of the black level message line; S4, the background system computes an average black level of each pixel channel of the black level message line after filtering correction; S5, the background system adjusts the output data offset; S6, the background system carries out black level correction on the input image data; and S7, the background system outputs a normal image. The system comprises a defect pixel correction module, a correction information computation module and a black level correction module, wherein the correction information computation module comprises an average black level computation module and a data output offset regulation module. According to the algorithm used for black level correction of the CMOS image sensor and the system thereof, the black level correction can be better carried out, the error is small, and the problems of color deviation and brightness unsaturation under the condition of a larger black level difference of four color channels are solved.

Description

technical field [0001] The invention relates to the field of electronic technology, in particular to an algorithm and system for black level correction of a CMOS image sensor. Background technique [0002] In recent years, due to the advantages of low cost, low voltage, and low power consumption, CMOS image sensors integrating photosensitive devices, analog readout circuits, digital control systems, and intelligent signal processing circuits have become more and more attractive. However, the dark current severely limits the performance of the CMOS image sensor, such as dynamic range and sensitivity, and causes FPN (fixed pattern noise, fixed pattern noise) and transient noise, thereby also reducing its noise performance. Since the dark current mainly comes from the interface defects in the field oxygen region and the boundary of the money slot isolation, it is more and more challenging to manufacture an image sensor with a low dark level as CMOS technology enters the deep su...

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Problems solved by technology

[0005] The object of the present invention is to provide a kind of algorithm and system thereof for the black level correction of CMOS image sensor, thus solve the aforementioned problems existing in the prior art

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