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浏览/检索结果: 共3条，第1-3条 帮助 限定条件 发表日期：2011     已选(0)清除 条数/页：5101520253035404550556065707580859095100   排序方式：请选择作者升序作者降序题名升序题名降序发表日期升序发表日期降序提交时间升序提交时间降序 A hybrid median filter for enhancing dim small point targets and its fast implementation (EI CONFERENCE) 会议论文 2011 International Conference on Multimedia and Signal Processing, CMSP 2011, May 14, 2011 - May 15, 2011, Guilin, Guangxi, China Yang Q. 收藏  |  浏览/下载：17/0  |  提交时间：2013/03/25 Weak stars and middle altitude orbit satellites or high altitude orbit satellites are presented as dim point targets in images of astronomical observation. They have low intensity and occupy few pixels in image. In most situations  the background of sky is always ununiform and there exists pulse noises. Thus results in targets submerging in background noises and low signal noise ratio (SNR). Median filter is an effective method for removing pulse noise. But it can blur image after modifying gray of non-noise pixels when image has low SNR. A hybrid median filter algorithm is proposed to process low SNR dim point targets image. The newly proposed method can suppress the pulse noises  also can increase target $SNR$ and does not add extra fake targets. The time complexity of median filter is O(N2)(N is the widow size) and is difficult to implement in hardware. For quasi real time application  a fast implementation of our hybrid median filter is proposed to reduce the time complexity to O(N). Experimental results show that the newly proposed algorithm is superior to ordinary median filter and fast median filter by comparing visual effect and performance. 2011 IEEE.   Efficient rate control technique for CCSDS image encoding (EI CONFERENCE) 会议论文 IEEE 2nd International Conference on Computing, Control and Industrial Engineering, CCIE 2011, August 20, 2011 - August 21, 2011, Wuhan, China Jin L. 收藏  |  浏览/下载：86/0  |  提交时间：2013/03/25 For the limitation of data transmission bandwidth and real time transmission demand  generally image compression is required to implement the precise and flexible rate control algorithm. Rate control is an important issue in the image compression field. This paper considers the problem of rate allocation to each encoded segment for CCSDS image compression. One straightforward method is to allocate an equal amount of rate to each segment based on the average of the total number of compressed bytes. The obvious drawback of this method is that different segment will be reconstructed to different quality  so the overall quality of the reconstructed image will not be optimized. For the shortage of the original rate control method  as to improve the overall quality of the reconstructed image  an improved rate control algorithm is proposed for CCSDS image encoding. The key component of the proposed rate control method is the appropriate rate allocation. Experiments on the test images show that the PSNR can be increased at about 0.3dB on average  compared to the original algorithm. Therefore  experimental results confirm the effectiveness of the proposed algorithm in terms of objective evaluation  and the rate-distortion performance of the reconstructed image is improved. 2011 IEEE.   A new approach to realize UART (EI CONFERENCE) 会议论文 2011 International Conference on Electronic and Mechanical Engineering and Information Technology, EMEIT 2011, August 12, 2011 - August 14, 2011, Harbin, China Wang Y.; Song K. 收藏  |  浏览/下载：23/0  |  提交时间：2013/03/25 In order to connect DSP which has synchronous serial ports to the devices implementing asynchronous communications protocol  a method to implement UART communications based on programmable logic device is proposed in the paper. In the proposed method  the core function of UART is integrated in CPLD with VHDL. Firstly  UART data frame format and operational principle of UART were introduced after reviewing some methods to realize UART. The methods to implement UART transmitter  UART receiver and baudrate generator using VHDL were illustrated in detail. Then pre-simulation and synthesize of VHDL program were executed. Finally  the test with bit error rate was carried out on physical system. Experimental results indicate that 75 percent of the GLB are used by UART  and the bit error rate is less than 109. The experiment was implemented utilizing the RS-422 protocol and the baudrate is 62.5kb/s. The proposed method can satisfy the system requirements of high integration  stabilization  low bit error rate  strong anti-jamming and low cost. 2011 IEEE.