Patent ID: 7873212

Claim:
A method for encoding an image having color components of each image pixel represented by a value of a high dynamic range, the method comprising: decomposing the image into a plurality of image blocks; separating, from the high dynamic range value of each pixel, color information and intensity information of the pixels in said image blocks; identifying a minimum intensity within said image blocks; storing a floating-point exponent of the minimum intensity in a table of compressed block data as a bias value; subtracting the bias value from the exponents of all intensity values within the image block to provide biased intensity values for each pixel; storing the number of leading zero bits of the floating-point bit pattern of the largest biased intensity value in the table of compressed block data, whereby a sign bit is ignored from the number of leading zero bits; compressing the intensity information of the pixels separately for each pixel in said image blocks; and compressing the color information of the pixels in said image blocks independently of the intensity information of the pixels in said image blocks using lossy compression schemes to provide compressed image data.