IMAGE PROCESSING APPARATUS AND IMAGE PROCESSING METHOD

摘要

By setting a parameter in accordance with features of a unique portion appearing in a print image, the unique portion in the print image is efficiently determined. The image is printed on a sheet along with a relative movement in a main scanning direction of the sheet and a print head on which multiple printing elements are arrayed in a sub-scanning direction. One division area is set such that a size in the main scanning direction is greater than a size in the sub-scanning direction. A shift amount from one division area to another division area is set such that a shift amount in the main scanning direction greater than a shift amount in the sub-scanning direction.

主权项

1. An image processing apparatus comprising:
an acquisition unit configured to acquire image data resulting from reading an image printed sequentially in a first direction; a setting unit configured to set a division size in the first direction and a second direction of a division area for dividing the image data, the second direction crossing the first direction, as well as a shift amount in the first direction and the second direction of the division area; a processing unit configured to perform a predetermined process including an averaging process on the image data according to the division size and the shift amount, a quantization process for quantizing a value obtained by performing the averaging process on image data in each division area shifted in accordance with the shift amount, and an addition process for adding values obtained by the quantization process; and an extraction unit configured to extract a unique portion from image data on which the predetermined process has been performed; wherein the setting unit sets (i) the division size greater in the first direction than in the second direction, and/or (ii) the shift amount greater in the first direction than in the second direction.