Chen Ken

Standard compliant multiple description coding based on regions of interest

A standard compliant multiple description coding based on regions of interest is presented for protecting a region of interest (ROI) in an image sent over lossy communication networks. The multiple description coding is introduced based on multiple-path transmit framework, which can offer a variety of tradeoff between transmission robustness and code efficiency, and the original model can be achieved by generating several subsets from the original image data. The proposed method exploit polyphase downsampling to split the original image date multiple descriptions. For the sake of protection, a higher bit rate is adopted in coding the ROI. Simulation shows the proposed method can offers intrinsic resiliency in case of loss in addition to effective ROI protection.

2-D multirate algorithms for efficient implementation of edge detection

Edge detection is a fundamental issue in image analysis. This paper proposes multirate algorithms for efficient implementation of edge detector, and a design example is illustrated. The multirate (decimation and/or interpolation) signal processing algorithms can achieve considerable savings in computation and storage. The proposed algorithms result in mapping relations of their z-transfer functions between non-multirate and multirate mathematical expressions in terms of time-varying coefficient instead of traditional polyphase decomposition counterparts. The mapping properties can be readily utilized to efficiently analyze and synthesize multirate edge detection filters. The Very high-speed Hardware Description Language (VHDL) simulation results verify efficiency of the algorithms for real-time Field Programmable Gate-Array (FPGA) implementation.

Redundancy insertion of frame-based multiple description video codec

In video stream transmission over unreliable networks, the loss of a packet may result in an entire video frame, which may consequently cause severe degradation of all subsequent frames. To solve the problem, based on prediction, presented in this paper is a new pre- and post processing method with flexible redundancy insertion between descriptions for Frame-based multiple description code. The simulation shows that the presented method demonstrates its adequate efficiency in preventing error propagation. Moreover, the system is more robust in the case of packet-loss over different networks.

EFFICIENT IMPLEMENTATION OF 3D FILTER FOR MOVING OBJECT EXTRACTION

In this paper the design and implementation of Multi-Dimensional (MD) filter, particularly 3-Dimensional (3D) filter, are presented. Digital (discrete domain) filters applied to image and video signal processing using the novel 3D multirate algorithms for efficient implementation of moving object extraction are engineered with an example. The multirate (decimation and/or interpolation) signal processing algorithms can achieve significant savings in computation and memory usage. The proposed algorithm uses the mapping relations of z-transfer functions between non-multirate and multirate mathematical expressions in terms of time-varying coefficient instead of traditional polyphase decomposition counterparts. The mapping properties can be readily used to efficiently analyze and synthesize MD multirate filters.