| 摘要 |
An image scanning apparatus comprises an input image scanner for scanning an input image area with a beam of radiation and deriving from an image on at least part of the input image area a digital signal representing the image, and an output image scanner for reproducing from said signal an output image on at least part of an output image area. The input image scanner and the output image scanner are arranged to scan the input and output image areas respectively simultaneously at a fixed relative rate, and the output and input images are represented as a series of pixels arranged in orthogonal directions at fixed resolutions. In the data path between the input and output scanners the digital signal is processed to change the size of the output image relative to the input image by using a data store whose data capacity is substantially less than that required to hold data corresponding to an image covering the whole of the input image area.
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