In depth analysis and evaluation of saliency-based color image indexing methods using wavelet salient features

Nowadays, most of the research works in the area of image retrieval try to build an image signature by considering the image as a whole. In this paper, we proposed an alternative based on the detection of some salient points in the image. For this purpose, we propose a new efficient salient point detector based on a wavelet transform. The efficiency of our detector lies in the representation of the wavelet coefficients by a zerotree data structure and by a saliency formulation that does not favor any direction. Thus, the detected salient points are located on sharp region boundaries whatever their direction. From the detected salient points, we build a color/texture signature by using jointly the well-known color correlogram extended to salient features and rotated wavelet filter responses. Experimental results conducted by adopting a global salient approach and a local salient approach show the effectiveness of the proposed scheme.