Image processing apparatus, image processing method, and computer readable medium

1. An image processing apparatus comprising:

an image dividing unit that divides a first image and a second image into a plurality of first divided images and a plurality of second divided images, respectively;

a corresponding divided image extract unit that extracts the second divided images corresponding to the first divided images;

a difference extract unit that extracts a difference image having a difference generated due to additional entry or extraction between pixels included within each of the first divided images and pixels included within each of the second divided images;

a first change unit that, in a case where the first divided images has such a movement relationship that it can be moved relative to the second divided images, changes a color of the second divided images into a first color;

a second change unit that changes a color of the difference image extracted by the difference extract unit into a second color; and

an image output unit that outputs the second divided images with the color changed by the first change unit and the difference image with the color changed by the second change unit.

2. The image processing apparatus as claimed in claim 1 , wherein the second change unit changes the second divided images, which are not extracted by the corresponding divided image extract unit, into a second color.

3. The image processing apparatus as claimed in claim 1 , further comprising a third change unit that, in a case where a difference is not extracted by the difference extract unit and the first divided image does not have the movement relationship, changes the second divided images into a third color.

4. The image processing apparatus as claimed in claim 1 , wherein the third color is lower in chroma and density than the first and second colors.

5. An image processing method comprising:

dividing, by a processor, a first image and a second image into a plurality of first divided images and a plurality of second divided images, respectively;

extracting the second divided images corresponding to the first divided images;

extracting a difference image having a difference generated due to additional entry or extraction between pixels included within each of the first divided images and pixels included within each of the second divided images;

changing, in a case where each of the first divided images has such a movement relationship that it can be moved relative to each of the second divided images, a color of the second divided images into a first color;

changing a color of the extracted difference image into a second color; and

an image output unit that outputs the second divided images with the changed color and the difference image with the changed color.

6. A non-transitory computer readable medium storing a program causing a computer to execute a process for performing image processing, the process comprising:

dividing a first image and a second image into a plurality of first divided images and a plurality of second divided images, respectively;

extracting the second divided images corresponding to the first divided images;

extracting a difference image having a difference generated due to additional entry or extraction between pixels included within each of the first divided images and pixels included within each of the second divided images;

changing, in a case where each of the first divided images has such a movement relationship that it can be moved relative to each of the second divided images, a color of the second divided images into a first color;

changing a color of the extracted difference image into a second color; and

an image output unit that outputs the second divided images with the changed color and the difference image with the changed color.