Massively Parallel Image Index for Vocabulary Tree Based Image Retrieval

Although vocabulary tree based algorithm has high efficiency for image retrieval, it still faces a dilemma when dealing with large data. In this paper, we show that image indexing is the main bottleneck of vocabulary tree based image retrieval and then propose how to exploit the GPU hardware and CUDA parallel programming model for efficiently solving the image index phase and subsequently accelerating the remaining retrieval stage. Our main contributions include tree structure transformation, image package processing and task parallelism. Our GPU-based image index is up to around thirty times faster than the original method and the whole GPU-based vocabulary tree algorithm is improved by twenty percentage in speed.