Method and system for correcting lens shading

A method for correcting lens shading of an image sensor, comprising:

• partitioning a reference image into a plurality of reference image blocks and extracting luminance values of four edge pixels at the edges of each of the plurality of reference image blocks and calculating a luminance weight value for each of the edge pixels;
• calculating a luminance weight value of each pixel of a corresponding reference image block, on the basis of luminance weight values of four edge pixels of the corresponding reference image block, for each of the plurality of reference image blocks;
• and
• correcting the luminance of an input image by multiplying the luminance weight value for each pixel, calculated by the luminance weight value calculator, with a luminance value of each pixel of the input image,
• wherein at least one of the foregoing steps is performed by a processor or hardwired logic.

An image sensor, comprising:

• a reference image luminance extractor, operative to partition a reference image into a plurality of reference image blocks, extract luminance values of four edge pixels at the edges of each of the plurality of reference image blocks, and calculate a luminance weight value for each of a plurality of edge pixels;
• a luminance weight value difference storage, operatively coupled to the reference image luminance extractor, operative to store a luminance weight value difference between a luminance weight value of an edge pixel and a luminance weight value of an adjacent edge pixel, adjacent to the edge pixel, for each of the plurality of edge pixels;
• a luminance weight value restorer, operatively coupled to the luminance weight value difference storage, operative to restore the luminance weight value difference to the luminance weight value;
• a luminance weight value calculator, operatively coupled to the luminance weight value restorer, operative to calculate a luminance weight value of each pixel of a corresponding reference image block on the basis of luminance weight values of four edge pixels of the corresponding reference image block for the plurality of reference image blocks by using the luminance weight value restored in the luminance weight value restorer;
• and
• a luminance corrector, operatively coupled to the luminance weight value calculator, operative to correct the luminance of an input image by multiplying a luminance weight value for each pixel, calculated in the luminance weight value calculator, by a luminance value of each pixel of the input image.

A method for correcting lens shading of an image sensor, comprising:

• partitioning a reference image into a plurality of reference image blocks, extracting luminance values of four edge pixels at the edges of each of the plurality of reference image blocks and calculating a luminance weight value for each of the edge pixels;
• storing a luminance weight value difference between a luminance weight value of an edge pixel and a luminance weight value of an adjacent edge pixel, adjacent to the edge pixel, for each of the plurality of edge pixels;
• restoring the luminance weight value difference to the luminance weight value;
• calculating a luminance weight value of each pixel of a corresponding reference image block on the basis of luminance weight values of four edge pixels of the corresponding reference image block for the plurality of reference image blocks by using the luminance weight value restored in the luminance weight value restorer;
• and
• correcting the luminance of an input image by multiplying a luminance weight value for each pixel, calculated in the luminance weight value calculator, by a luminance value of each pixel of the input image,
• wherein at least one of the foregoing steps is performed by a processor or hardwired logic.