In order to improve both speed and accuracy of image database retrieval

particularly for large image database

a two-level query technique based on HSV colorspace is proposed in this paper. Firstly

we narrow the scope of inquery by the use of color moments which is simple and effective. Then

we split images into 4×4 overlapping sub-blocks and extract color histograms of sub-blocks for the second-level retrieval of image database to obtain a more accurate searching results. The benefits of such a block are not only obtaine the spatial distribution of image information

but also highlight the main part of the image and fully restrict the scope of the background. This technique reduces the computational complexity compared to an independent sub-block. As shown in the experiments

with an example image given by the user

good retrieval results can be obtained by two-level query technique with color features.