Contrast correcting circuit

摘要

A contrast correcting circuit for preventing white distortion in a dark screen comprises: an integrator for integrating brightness levels of video signals, and for calculating a sum of the brightness levels; a ROM for storing different types of table data exhibiting contrast conversion characteristics according to the brightness; a selection signal generator for setting as a reference value the sum of the brightness levels of all of the pixels when the brightness levels are at a maximum, for comparing the reference value with an integration output of the integrator, and for instructing the ROM to selectively output table data suitable for the brightness of a screen selected from the different types of table data; and a RAM for storing a conversion table for correcting the contrasts of the video signals by means of the table data.