Patent ID: 8311107

Claim:
An image data compression device, comprising a prediction device configured to predict a pixel level value of a pixel to be compressed when image data is compressed, performs encoding after quantizing a difference value between a prediction result of the prediction device and an actual pixel level value, or performs encoding on a basis of the difference value, wherein the prediction device calculates a plurality of candidates for a prediction value using a pixel level value around a pixel to be compressed for each of an image format represented as a signal indicating an image having a strong pixel correlation in a horizontal direction and an image format represented as a signal indicating an image having a strong pixel correlation in a vertical direction, narrows the plurality of candidates for the prediction on a basis of the pixel level value around the pixel to be compressed, and determines one of the narrowed candidates for the prediction value as the prediction value on a basis an image format of the image data which is represented as a signal indicating an image having a strong pixel correlation in a horizontal direction or a signal indicating an image having a strong pixel correlation in a vertical direction, wherein the image having a strong pixel correlation in the horizontal direction is an interlace image, and the image having a strong pixel correlation in the vertical direction is a progressive image, wherein a pixel left to the pixel to be compressed is defined as A, a pixel above the pixel to be compressed is defined as C, a pixel upper left to the pixel to be compressed is defined as B, and m and n are coefficients, and a candidate for the prediction value corresponding an intermediate value among A, B, and C is selected as the prediction value from among three candidates for a prediction value “A” which is a candidate for the prediction value corresponding A, “(m*A+n*C)/(m+n)” which is a candidate for the prediction value corresponding C, and “A+(m*A+n*C)/(m+n)−(m*A+n*B)/(m+n)” which is a candidate for the prediction value corresponding B, and wherein when the image data is a progressive image, m is 0 and n is 1, and when the image data is an interlace image, m is 1 and n is 1 or 3.