Perception based image retrieval

We created,an image,indexing system,based,on some,of the known properties of the early stages,of human vision. We used,a color space known,to underlie,the second,stage,of human color vision and,stored chromaticity and luminance information in two,logarithmic-radial histograms. A third, spatial index encodes ñ in analogy to the spatial frequency,representation,in the visual cortex ñ information,about,orientation and spatial scale. The indices were,evaluated,by comparing,the computed,similarity values with human,judgments,quantitatively and objectively in a 2AFC design. For the experiments we used a heterogeneous database of 60,000 digitized photographs. 2