Patent ID: 8026935

Claim:
A low-backlight image visibility enhancement method for use on a backlit-type display unit for visibility enhancement of an input image that is to be displayed on the backlit-type display unit under a low-backlight condition; the low-backlight image visibility enhancement method comprising: setting a backlight reduction ratio as a control parameter which is the ratio of the actual backlight intensity produced by the backlit-type display unit during operation against a rated maximum backlight intensity; extracting the brightness information of the input image to thereby produce a luminance-based image; decomposing the luminance-based image into a base-layer image and a detail-layer image, wherein the base-layer image is a low-pass filtered version of the original luminance-based image within a low-pass band, while the detail-layer image is a high-pass filtered version of the original luminance-based image within a high-pass band beyond the low-pass band; performing a brightness compensation process on the base-layer image in accordance with an average-brightness mapping scheme based on the backlight reduction ratio and the average brightness value of the input image to thereby produce a brightness-compensated base-layer image; performing a contrast enhancement process on the detail-layer image to thereby produce a contrast-enhanced detail-layer image; superimposing the brightness-compensated base-layer image with the contrast-enhanced detail-layer image to thereby produce a single combined image; and performing a color conversion process on the combined image to thereby produce an output image for displaying on the backlit-type display unit.