An Image Enhancement Based CDVS Matching Algorithm.

Compact Descriptor for Visual Search (CDVS) provides a standardized bitstream syntax for mobile image retrieval and matching applications. Although the standard CDVS algorithm has significant advances in the images with the good lighting condition, this approach often fails on dealing with the low-light images. A CDVS matching algorithm based on image enhancement is proposed. Firstly, a histogram equalization method is used for improving the quality of the pictures on low-light conditions to increase the matching number of the key points. Then, a same image enhancement method, which is mainly according to the homomorphic filtering, is adopt as the preprocessing for enhancing the contrast of the image with suppressing the low frequency signal and highlighting the high frequency signal to better extract the descriptors. Experimental results show that the proposed algorithm performs favorably against the standard CDVS algorithm on low-light images. Furthermore, the histogram equalization based CDVS matching algorithm has the best performance comparing with the homomorphic filtering method and the standard CDVS matching algorithm.