Abstract: The discrete cosine transform (DCT) can be used totransform two images into a space where it is easy toobtain an estimate of their perceptual distance. Weused this method to find the closest fit of the ASCIIsymbols (which includes the English alphabet, numbers,punctuation, and common symbols) to rectangularsegments of a gray-scale image. Each segment wasconverted into a DCT coefficient matrix which wascompared to the coefficient matrix of each ASCIIsymbol. The image segment was replaced with the symbolthat had the least weighted Euclidean distance. Thus, apage of text was generated that resembled the originalimage. The text image format has the advantage that itcan be displayed on a non-graphic terminal or printer.It can also be sent via electronic mail withoutrequiring further processing by the receiver. Theprocessing scheme can also be used to preview storedimages when transmission bandwidth is limited or agraphic output device is unavailable. !7
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