Patent ID: 11875481
Assignee: REALTEK SEMICONDUCTOR CORPORATION
Field: Computer technology (Electrical engineering)
Classification: CPC G | IPC G

Claim 0:
1. A method for compensating an image having fixed pattern noise, performed by a system including a 4-cell sensor and a processing circuit, comprising:
dividing the image into multiple grids in an array, wherein each of the grids includes multiple 4-cell groups, each of the 4-cell groups includes 4 cells that record pixel values generated by the 4-cell sensor, and each cell includes 4 pixels;
calculating a channel average that is a pixel average for every channel of each of the grids;
calculating a pixel average of pixels in a 4-cell group;
calculating a fixed pattern noise compensation coefficient for every pixel of the image according to a ratio of the pixel average of every channel in each of the grids and the pixel average of pixels of every channel; and
performing fixed pattern noise compensation for the image, wherein the fixed pattern noise compensation coefficient (gain_intp) of a current pixel is multiplied by a pixel value (CP_ori(x,y)) of the current pixel, and a parameter “adjust_rate” is introduced to adjust strength of the fixed pattern noise compensation coefficient with respect to different intensities of different light sources so as to complete fixed pattern noise compensation;
wherein the pixel value (CP(x,y)) with the fixed pattern noise compensation is obtained by a formula of CP (x,y)=CP_ori (x,y)=gain_intp=adjust rate.