Yongdong Zhang

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In computer vision and multimedia search, it is common to use multiple features from different views to represent an object. For example, to well characterize a natural scene image, it is essential to find a set of visual features to represent its color, texture, and shape information and encode each feature into a vector. Therefore, we have a set of(More)
Learning effective feature representations and similarity measures are crucial to the retrieval performance of a content-based image retrieval (CBIR) system. Despite extensive research efforts for decades, it remains one of the most challenging open problems that considerably hinders the successes of real-world CBIR systems. The key challenge has been(More)
Given the tremendous growth of online videos, video thumbnail, as the common visualization form of video content, is becoming increasingly important to influence user's browsing and searching experience. However, conventional methods for video thumbnail selection often fail to produce satisfying results as they ignore the side semantic information (e.g.,(More)
Binary hashing has been widely used for efficient similarity search due to its query and storage efficiency. In most existing binary hashing methods, the high-dimensional data are embedded into Hamming space and the distance or similarity of two points are approximated by the Hamming distance between their binary codes. The Hamming distance calculation is(More)
Both the motion-detection and intra-field interpolation filter are important factors affect the efficiency of motion adaptive de-interlacing. New accurate motion detection (AMD) algorithm is proposed to improve the accuracy of motion detection, which reduces the possibility of error motion detection with a median filter. To improve the efficiency of(More)
Despite the massive growth of web-shared videos in Internet, efficient organization and monitoring of videos remains a practical challenge. While nowadays broadcasting channels are keen to monitor online events, identifying topics of interest from huge volume of user uploaded videos and giving recommendation to emerging topics are by no means easy.(More)
Video encryption plays an important role in data security guarantee, which is increasingly important with the development of multimedia technology. A great deal of effort has been made in recent years to develop video encryption methods. However, few studies focus on visual security evaluation, which has significant impact in measuring the effectiveness of(More)
Scrambling is widely used to protect privacy in surveillance video. However, as a critical issue in privacy protected video scrambling, drift error has not been adequately studied. In this paper, we focus on drift error prevention for different elements scrambling in privacy protected H.264/AVC video, which is the prevailing coding standard. A restricted(More)