Patent ID: 8655064
Filing Date: 2014-02-18
Classification: H04N

Abstract:
1. An image compression circuit that compresses pieces of image data of four adjacent pixels, the image compression circuit comprising: an image calculator for calculating a luminance of each pixel from said image data of each pixel expressed by an RGB color space; a compression-system decision unit for deciding on a first RGB compression system compressing said image data of each pixel expressed by the RGB color space when a variation in luminance of all the pixels falls within a predetermined range based on the luminance of each pixel, which is calculated by said image calculator, deciding on a second RGB compression system, which differs from said first RGB compression system and compresses said image data of each pixel expressed by the RGB color space, when the variation in luminance of all the pixels does not fall within said predetermined range, and when the variation in luminance of the pixel included in a group falls within said predetermined range in each of two groups into which each pixel is divided based on the luminance of each pixel, and deciding on a YCbCr compression system when the variation in luminance of the pixel included in said group does not fall within said predetermined range in at least one of said two divided groups; and a compression processor for compressing said image data into image data of one pixel expressed by the RGB color space based on the system decided on by said compression-system decision unit for said first RGB compression system, compressing said image data into image data of one pixel expressed by the RGB color space in each of said groups for said second RGB compression system, and compressing said image data into data including the luminances of the four pixels and image data of one pixel expressed by a YCbCr color space in each of said groups for said YCbCr compression system.