PURPOSE: To provide an image processor which can automatically compile and output the contents of originals in a simple constitution.

CONSTITUTION: The multilevel image data received from an original reading part 1 are binalized by a binarizing circuit 4, and at the same time the density of the image data is decided by a density deciding part 2 at the specific color parts that are marked in both main and secondary scanning directions in an original. A filter processing part 3 applies the filter processing to the image data to decide the genuine specific color parts only when the image data are defined as a group of plural picture elements at the specific color parts. Then a decided area setting part 6 sets a decided area to the image data on the specific color parts that undergo the filter processing. A control signal generating part 7 sets a conversion area in the original when the picture elements of the specific color parts exceed a prescribed number in the decided area. Then an output processing part 8 converts the binary image data received from the circuit 4 and included in the conversion area into a cycle pattern generated by a cycle pattern generating part 5 and outputs this pattern.