METHOD, PROGRAM, AND APPARATUS FOR PREVENTING A REPRODUCTION OF AN ANTI-COPY DOCUMENT, AND A MEDIUM STORING THE PROGRAM

An image processing apparatus includes a scanning mechanism, first and second memories, an image accumulating mechanism, a detecting mechanism, a determining mechanism, and a code assigning mechanism. The first memory stores a reference dot pattern indicating an anti-copy background dot pattern. The second memory stores image data. The image accumulating mechanism accumulates image data of an original image into the second memory. The detecting mechanism detects a background dot pattern embedded in a background image included in the image data of the accumulated original image. The determining mechanism compares the detected background dot pattern with the reference dot pattern and determines whether the detected background dot pattern is substantially identical to the reference dot pattern. The code assigning mechanism assigns an identification code to the image data having the detected background dot pattern when the detected background dot pattern is determined as substantially identical to the reference dot pattern.