Image processing apparatus, image processing method, and computer-readable medium for image data compression

摘要

An image processing apparatus comprises: a division unit which divides the input image data into blocks each including a predetermined number of pixels; a determination unit which determines whether the number of colors that is the number of types of colors of the pixels included in the block is not less than a predetermined number; a pseudo halftone processing unit which performs pseudo halftone processing of image data for the block if the number of colors in the block is not less than the predetermined number; an acquisition unit which acquires a color arrangement and color information in each of the block, in which the determination unit determines that the number of colors is less than the predetermined number, and the block having undergone the pseudo halftone processing; and a storage unit which stores the color arrangement and the color information, acquired, for each block.

主权项

1. An image processing apparatus which compresses input image data, comprising:
a division unit which divides the input image data into blocks each including a predetermined number of pixels; a determination unit which determines, for each of the blocks divided by said division unit, whether a number of colors that is a number of types of colors of the pixels included in the block is not less than a predetermined number; a halftone processing unit which performs halftone processing of image data of blocks for which it is determined by said determination unit that the number of colors is not less than the predetermined number, wherein said halftone processing unit does not perform the halftone processing of image data of blocks for which it is determined that the number of colors is less than the predetermined number; an acquisition unit which acquires a color arrangement and color information in each of blocks for which it is determined by said determination unit that the number of colors is less than the predetermined number, and further acquires a color arrangement and color information in each of blocks having undergone the halftone processing by said halftone processing unit; and a storage unit which stores the color arrangement and the color information acquired by said acquisition unit, wherein said storage unit further stores a block, processed before a currently processed block, the image processing apparatus further comprises a replacement determination unit which determines whether the currently processed block can be replaced with the block stored in said storage unit, and in a case where said replacement determination unit determines that the currently processed block can be replaced with the block stored in said storage unit, the currently processed block is associated with the block stored in said storage unit.