Patent ID: 6647127
Filing Date: 2003-11-11
Classification: G06T

Abstract:
An image data manipulation method in which an image is segmented into a plurality of blocks each including a predetermined number of pixels in each of vertical and horizontal directions and the image data described by the discrete cosine transform of the luminance information and the color information is changed using a computer having a central processing unit and a storage unit, comprising the steps of:changing the a DC component value of at least one of said luminance information and said color information for each predetermined block to a value different by at least a predetermined value from the original value attaching ID information for identifying the block which has its image data manipulated to said block; and wherein said step of changing said DC component value includes the substep of inverting the sign of the value P of said image data and then subtracting a predetermind value E in the case were said value P is not less than a threshold value A or less than a threshold value B, the substep of subtracting a predetermined value D from said value P in the case where said value P is less than the threshold value A and not less than the threshold value C, and the substep of adding the predetermined value D to said value P in the case where said value P is less than the threshold value c and not less than the threshold values B, where the relation holds that B