As a circuit and method for improving image quality using a matching histogram equalization - average quantized

摘要

An image enhancement circuit and a method therefor including the steps of quantizing the level of an input image signal, obtaining a cumulative density function on the basis of a gray level distribution of a screen unit with respect to the quantized image signal, outputting a cumulative density function value interpolated on the basis of the quantized cumulative density function value, calculating the mean level of the input image signal in a screen unit, and controlling a transform function to map the input image signal to a gray level and map the mean level to itself, by using the interpolated cumulative density function as the transform function. In addition, the image enhancement method includes the steps of outputting a compensated mean level by adding a corrected value depending on a predetermined correction function to the mean level, and controlling the interpolated cumulative density function as a transform function to map an input image signal to a new gray level on the basis of the interpolated cumulative density function value and to map the mean level to the compensated mean level. Thus, contrast is enhanced, and the mean brightness of a given image is continuously maintained.