Image enhancing method using mean-separate histogram equalization and a circuit therefor

摘要

An image enhancing method using a mean-separate histogram equalization method is disclosed. An input image signal is divided into two sub-images in a picture unit according to a mean level of the input image signal. Then, cumulative density functions for each sub-image are calculated. Afterwards, the input sample is mapped into two gray levels, each of which belongs to a first range and a second range, by using a first and a second transform functions defined by use of the cumulative density functions, respectively. Finally, one of two mapped levels is selected depending on the magnitude of the input sample. As a result, the brightness of the given image can be preserved while the contrast is enhanced.