| 摘要 |
PURPOSE:To achieve improvement of gradation by preventing a stripe pattern which occurs owing to correction of errors, by a method wherein an image signal is turned to binary signal by comparing it with a threshold value which varies with each picture element, and an error which occurs in that case is corrected. CONSTITUTION:Image data which have been read with an input device 1 are successively sent to an A/D converter 2. Then, for instance, data of each picture element are converted to digital data of eight bits. They are thereby quantized to data having a gradation number of 256 level. Then correction such as shading correction or the like for correction of uneveness in sensitivity of a sensor and of uneveness in illumination owing to an illumination source is processed by digital operation with a correction circuit 3. Then, this corrected signal 100 is inputted to a binary processing circuit 4. Multivalue data are converted to binary data and sent to an output device 5 as a signal 200. |
