Patent ID: 8390875
Filing Date: 2013-03-05
Classification: G06K,H04N

Abstract:
1. An image processing apparatus comprising: a coefficient calculation unit that calculates a conversion coefficient for converting image data having a predetermined number of pixels to image data having a smaller number of pixels than the predetermined number of pixels, including a coefficient multiplied by an integer power of 2; a calculation unit that multiplies each pixel value of image data prior to image reduction processing by the conversion coefficient previously calculated by the coefficient calculation unit thereby to calculate each pixel value of the image data subjected to the image reduction processing; and a shift unit that shifts each of the pixel values calculated by the calculation unit by a number of bits to counteract the integer power of 2-multiplied coefficient included in the conversion coefficient, wherein when input image data represent a binary image, a reduction ratio is twice or more and the reduction ratio is not an integer power of 2, the calculation unit converts the input image data to a multivalued image data at the reduction ratio as an integer power of 2 by area tone reproduction processing, and then calculates each pixel value of the image data subjected to the image reduction processing.