Method and apparatus for pixel level luminance adjustment

摘要

A method for adjusting the luminance IMHI of pixels in a high resolution image includes first forming a low resolution image of the original by grouping pixels into superpixels such as 8x8 blocks. A low resolution luminance correction value delta LO is determined for each superpixel by comparing the luminance of the superpixel to both a predetermined darkness threshold TD and a predetermined brightness threshold TB. The low resolution luminance correction value delta LO is modified to yield delta 'LO for each superpixel by forming islands of the superpixels and smoothing delta LO between superpixels within each island. Finally, a high resolution luminance correction value delta HI is calculated for each pixel of the original high resolution image by comparing the luminance IMHI of each pixel to both TD and TB, keeping in mind that delta HI is generated through a series of mathematical computations as a function of both the pixel luminance IMHI and the low resolution luminance correction value delta LO. Each pixel of the original image is adjusted by the corresponding high resolution luminance correction value delta HI and a luminance adjusted image is produced.