An adaptive image denosing technique was proposed to achieve the tradeoff between details retain and noises removal. In order to achieve this objective, the contourlet transform was introduced and a new threshold meth...An adaptive image denosing technique was proposed to achieve the tradeoff between details retain and noises removal. In order to achieve this objective, the contourlet transform was introduced and a new threshold method, namely CWinShrink, is presented. It shrinks the contourlet coefficients with adaptive shrinkage factors. The shrinkage factors were calculated with reference to the sum of squares of the contourlet coefficients within the neighborhood window. This approach achieves enhanced results for images those are corrupted with additive Gaussian noise. In numerical comparisons with various methods, for a set of noisy images （the PSNR range fi＇om 10.86dB to 26.91dB） , the presented method outperforms VisuShrink and Wiener filter in terms of the PSNR. Experiments also show that this method not only keeps the details of image but also yields denoised images with better visual quality.展开更多
This paper describes a high security data transmission system over X-band microwave frequency. The paper has two parts. The first part deals with encryption of binary data by Advanced Encryption Standard (AES) using V...This paper describes a high security data transmission system over X-band microwave frequency. The paper has two parts. The first part deals with encryption of binary data by Advanced Encryption Standard (AES) using VHDL modeling of Field Programmable Gate Array (FPGA). The second part deals with a novel idea of transmitting the encrypted data by using a single klystron. This requires the simultaneous generation of a pair of two independent RF frequencies from a reflex klystron working for X-band frequency range. In this scheme, the klystron is suitably biased on the repeller terminal and superimposed on a train of AES encrypted binary data so as to create two RF frequencies one corresponding to negative peaks and the other one to the positive peaks of the data resulting in an Frequency Shift Keying (FSK) signal. The results have been verified experimentally.展开更多
基金Sponsored by Key Lab of Optoelectronic Technology &System,Department of Education, China(Grant No.200373 -1 -2).
文摘An adaptive image denosing technique was proposed to achieve the tradeoff between details retain and noises removal. In order to achieve this objective, the contourlet transform was introduced and a new threshold method, namely CWinShrink, is presented. It shrinks the contourlet coefficients with adaptive shrinkage factors. The shrinkage factors were calculated with reference to the sum of squares of the contourlet coefficients within the neighborhood window. This approach achieves enhanced results for images those are corrupted with additive Gaussian noise. In numerical comparisons with various methods, for a set of noisy images （the PSNR range fi＇om 10.86dB to 26.91dB） , the presented method outperforms VisuShrink and Wiener filter in terms of the PSNR. Experiments also show that this method not only keeps the details of image but also yields denoised images with better visual quality.
文摘This paper describes a high security data transmission system over X-band microwave frequency. The paper has two parts. The first part deals with encryption of binary data by Advanced Encryption Standard (AES) using VHDL modeling of Field Programmable Gate Array (FPGA). The second part deals with a novel idea of transmitting the encrypted data by using a single klystron. This requires the simultaneous generation of a pair of two independent RF frequencies from a reflex klystron working for X-band frequency range. In this scheme, the klystron is suitably biased on the repeller terminal and superimposed on a train of AES encrypted binary data so as to create two RF frequencies one corresponding to negative peaks and the other one to the positive peaks of the data resulting in an Frequency Shift Keying (FSK) signal. The results have been verified experimentally.
