Adaptive image shading correction method and adaptive image shading correction system

An adaptive image shading correction system, comprising:

• an image capturing device configured to obtain a current frame;
• an image processing circuit configured to receive the current frame and including a processing circuit, wherein the processing unit is configured to perform the following steps:
• dividing the current frame into a plurality of blocks;
• selecting a plurality of block pairs from the plurality of blocks, wherein each of the block pairs includes an inner block and an outer block, the inner block is one of the plurality of blocks in an inner area of the current frame, and the outer block is one of the plurality of blocks in an outer area of the current frame;
• performing a filtering process for each of the plurality of block pairs, and the filtering process including the following steps:
• obtaining a brightness difference and a saturation difference of a current block pair;
• determining whether the brightness difference and the saturation difference meet a brightness condition and a saturation condition, respectively;
• in response to determining that the brightness difference and the saturation difference meet the brightness condition and the saturation condition, respectively, further obtaining a hue statistical data of the current block pair;
• determining whether the hue statistical data meets a hue similarity condition;
• in response to determining that the hue statistical data meets the hue similarity condition, comparing sharpnesses of the current block pair to determine whether a sharpness similarity condition is met;
• and
• in response to determining that the sharpness similarity condition is met, taking the current block pair as a filtered block pair;
• in response to obtaining multiple ones of the filtered block pairs, calculating a sum similarity threshold according to the hue statistic data, the saturation difference, and the brightness difference of each of the multiple ones of the filtered block pairs;
• for each filter block of the filtered block pairs, determining whether there is an individual threshold that is less than the sum similarity threshold;
• using the filtered blocks having the individual threshold value smaller than the sum similarity threshold value to calculate a shading compensation value;
• and
• adjusting the current frame with the shading compensation value to generate a compensated frame.