METHOD AND DEVICE FOR AUTOMATIC TELEVISION-IMAGE CONTRAST ENHANCEMENT Russian patent published in 2004 - IPC

FIELD: television engineering; enhancing image contrast. SUBSTANCE: proposed method involves following procedures: raster section is chosen on television image, video signal is respectively gated and processed to enhance image contrast, processing path is divided into brightness channel and chrominance channel; brightness channel has S-shaped amplitude characteristic, and color saturation is enhanced in chrominance channel throughout entire chosen section of raster. Device implementing this method has first locking unit 1, second locking unit 8, first amplifier 2, second amplifier 18, nonlinear amplifier 9, output amplifier 4, first switch 3, second switch 14, third switch 17, sync selector 5, window generator 6, positioner 7, chrominance subcarrier discrimination unit 16, first control unit 10, second control unit 11, third control unit 20, black-color detector 12, white-color detector 13, subcarrier swing detector 19, and adder 15. EFFECT: enlarged contrast enhancement range of low-contrast parts even in presence of high- contrast parts in contrast enhancement area. 1 cl, 2 dwg