Local contrast enhancement method and apparatus

A local enhancement apparatus, comprising:

• a block divider for dividing an image into a plurality of blocks, which include at least a first block, a second block horizontally adjacent to the first block, a third block vertically adjacent to the first block, and a fourth block horizontally adjacent to the third block;
• a block histogram generator for generating histograms of the blocks respectively;
• a block enhancement function generator for generating enhancement functions of the blocks respectively based on the corresponding histograms, wherein the enhancement functions include at least a first enhancement function of the first block, a second enhancement function of the second block, a third enhancement function of the third block, and a fourth enhancement function of the fourth block;
• a vertical interpolator for processing each pixel in the blocks by generating an first vertically interpolated pixel value for a current pixel of the first block based on the first enhancement function and the third pixel value for the current pixel of the first block based on the second enhancement function and the fourth enhancement function;
• and
• a horizontal interpolator for generating an enhanced pixel value for the current pixel based on horizontally interpolating the first vertically interpolated pixel value and the second vertically interpolated pixel value.

A local enhancement apparatus comprising:

• an enhancement module for dividing an image into a plurality of blocks, and generating histograms on each of the blocks to generate corresponding first block and a second block adjacent to the first block, and the enhancement functions include at least a first enhancement function of the first block and a second enhancement function of the second block;
• an interpolation module for generating an interpolated enhancement function for a current pixel of the first block, by interpolating coefficients of the first enhancement function and the second enhancement function;
• and
• a mapping unit for generating an enhanced pixel value by applying the pixel to the interpolated enhancement function.