Method for transforming an image descriptor based on a gradient histogram and relative image processing apparatus

摘要

A method for transforming an image descriptor, based on a gradient histogram (h) having a plurality of histogram bins (hi), into a transformed gradient histogram descriptor (v) including a set of values (vj), wherein it is provided the step of applying at least one criterium for calculating the set of values (vj), at least one criterium having a location criterium of the histogram bins (hi). The invention also relates to an image processing device suitable for carrying out the method.

主权项

1. A method for transforming an image descriptor, for controlling information content and discriminative power of the image descriptor against storage and/or transmission costs of the image descriptor, the method comprising:
receiving an image descriptor based on a gradient histogram, the gradient histogram comprising a plurality of histogram bins containing a first set of values that are calculated at image sample points in a region around an image keypoint and accumulated into orientation histograms summarizing the contents over image subregions; applying at least one location criterium of said histogram bins for transforming said gradient histogram, wherein said location criterium provides for calculating a second set of values representative of image sample points around said image key point derived from gradient histogram bins which exhibit a plurality of angular separations; generating a transformed image descriptor comprising said second set of values.