Image processing apparatus including binary data producing unit

摘要

An image data processing apparatus binary-codes an image signal obtained from an image sensor of the CCD type or the like so as to output a binary-coded image signal. The image signal obtained from the image sensor A/D-converted into digital image data. Based upon the digital image data, average values of luminance values of the digital image data are calculated for an array of pixels in a preselected area of the CCD. This average value is used as a threshold level for binary coding the image data for these pixels at the center portion of this preselected area. Furthermore, to detect coutours this data processing apparatus calculates a gradient in the luminance values of the pixels in a portion of the preselected area of the CCD in an X direction and a Y direction, and the gradient value is used to obtain binary-coded data in accordance with the above-described method.