专利名称：Histogram/variance mechanism for
detecting prence of an edge within block
of image data
发明人：Scott J. Daly
申请号：US07/444470
申请日：19891201
公开号：US05150433A
公开日：
19920922
专利内容由知识产权出版社提供
摘要：An edge detection mechanism for an imagery signal compression and transmission system process histogram and variance data to identify the prence of a uniform area with a block of transform signals. The prence of an edge within an image block, for which corresponding transform coefficients are obtained, is identified by initially generating a histogram of the image block. If the maximum value of the histogram exceeds a first threshold value, a uniform area is inferred, and adaptive quantization that would otherwi be carried out prior to executing a minimum redundancy encoding scheme is bypasd. If the maximum value of the histogram does not exceed the first threshold value, a t of variance calculations is carried out for u with a further quence of edge detection decisions. The total variance and low frequency variance of the block are determined in accordance with the transform coefficients associated with the image block. The results of the variance calculations are then procesd with further thresholds and the histogram maximum value. If the abnce of an edge is inferred, the transform coefficients associated with the image block are quantized using adaptive quantization.
申请人：EASTMAN KODAK COMPANY 代理人：Edward Dugas
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