In the graphics data memory expedient which possesses with the lust information housing territory which manages the color which is used with the data pad

摘要

PROBLEM TO BE SOLVED: To provide a data-embedding device which can embed much information into a small-sized picture constituted of simple shape with a small number of colors and which does not degrade picture, even if the picture is compared with an original picture and to provide a data extraction device, the methods for the devices and a recording medium having the methods recorded thereon. SOLUTION: Object image data structure has a color information storage area and a pixel information storage area as components. The color information storage area in the image data structure is envisaged as divided into a plurality of small areas, and bit values corresponding to the individual small areas are defined. Index numbers stored for the individual pixels in the pixel information storage area are changed to index numbers belonging to the small areas, corresponding to the bit values of information to be embedded. Thus, information on one or more bits per pixel can be embedded. Much information are embedded in the small-sized image which is constituted of a simple shape with a small number of colors without deteriorating the quality and information can be extracted from the embedded image.