Patent ID: 8774505
Filing Date: 2014-07-08
Classification: G06K

Abstract:
1. A method of fixed bit-rate image compression which encodes a plurality of 2×2 coding units from an image, wherein the 2×2 coding units contains an upper left pixel, an upper right pixel, a lower left pixel, and a lower right pixel in a matrix arrangement, the method comprising the steps of: (A) receiving the plurality of 2×2 coding unit respectively; (B) determining whether the 2×2 coding unit is a man-made pattern and, if yes, the 2×2 coding unit being determined to be the man-made pattern, otherwise the 2×2 coding unit being determined to be a natural pattern, wherein the man-made pattern includes a first man-made pattern which indicates that the four pixels present two strips in a horizontal direction, a second man-made pattern which indicates that the four pixels present two strips in a vertical direction, a third man-made pattern which indicates that the four pixels present two strips crossed at 45 degree direction, and fourth to seventh man-made patterns which indicate that the four pixels present a combination of triangle and single point; (C) performing a differential error encoding and a quantization and lookup on the 2×2 coding unit of man-made pattern for generating a first coded data; (D) performing a color domain transform on the 2×2 coding unit of natural pattern for generating a 2×2 color domain transform unit; (E) performing a discrete cosine transform on the 2×2 color domain transform unit for generating a 2×2 frequency domain unit; and (F) performing the quantization and lookup on the 2×2 frequency domain unit for generating a second coded data.