Image process with spatial periodicity measure

摘要

An image manipulation process is controlled by a spatial periodicity measure formed for an image or an image block by measuring the sparseness of the two-dimensional spatial frequency spectrum of the image on a scale of zero to unity in which a two-dimensional spatial frequency spectrum having all equal values has a sparseness of zero and in which a two-dimensional spatial frequency spectrum having only one non-zero value has a sparseness of unity. Sparseness may be measured by allocating values of the spectrum to frequency bins and counting the number of bins that contain non-zero values; comparing values of the spectrum with a threshold and counting the number of values that exceed the threshold; or forming a function of the mean-square value and the mean value of the spectrum values.

主权项

1. A method of controlling an image manipulation process in a processor, the method comprising the steps of:
forming a spatial periodicity measure for at least part of an image; and controlling an image manipulation process in dependence on said spatial periodicity measure; wherein the step of forming a spatial periodicity measure comprises: measuring the sparseness of the two-dimensional spatial frequency spectrum of the image on a scale of zero to unity in which a two-dimensional spatial frequency spectrum having all equal values has a sparseness of zero and in which a two-dimensional spatial frequency spectrum having only one non-zero value has a sparseness of unity; and deriving a spatial periodicity measure data that is a function of said sparseness of the two-dimensional spatial frequency spectrum.