One of the limitations of using OFDM technique is its higher PAPR in the time domain signal. The higher PAPR OFDM signal would cause the fatal degradation of BER performance and undesirable spectrum regrowth in the no...One of the limitations of using OFDM technique is its higher PAPR in the time domain signal. The higher PAPR OFDM signal would cause the fatal degradation of BER performance and undesirable spectrum regrowth in the nonlinear channel. One of the promising PAPR reduction methods for OFDM signal is the Partial Transmit Sequence (PTS) method which can achieve better PAPR performance with reasonable computation complexity. However the PTS method is required to inform the phase coefficients of PTS as the side information to the receiver for the correct demodulation of data information through the data or separate channels. To simplify the transceiver of OFDM system with the PTS method, the phase coefficients of PTS are usually embedded in the data information. However since the phase coefficients of PTS are obtained after the PTS processing only for the data information at each OFDM symbol, it is hard to embed the phase coefficients of PTS in the data information separately without degradation of PAPR performance. To solve this problem, this paper proposes a new PAPR reduction method based on the packet-switched transmission systems in which all the clusters within the certain number of OFDM symbols have the sequential cluster ID numbers embedded in the header of each cluster. The salient features of the proposed method are to reduce the PAPR performance by re-ordering of clusters (ROC) in the frequency domain at the transmitter and to reconstruct the original ordering of clusters by using the cluster ID number demodulated from each cluster at the receiver. This paper also proposes a reduction technique of computation complexity for the proposed ROC method by using the feature of IFFT processing. This paper presents various computer simulation results to verify the effectiveness of the proposed ROC method with the reduction technique of computation complexity.展开更多
In the field of economy, there are more and more electronic scanning cash images, which need to be compressed in a higher compression ratio. This paper proposes a specific compression algorithm for cash images. First,...In the field of economy, there are more and more electronic scanning cash images, which need to be compressed in a higher compression ratio. This paper proposes a specific compression algorithm for cash images. First, according to cash image characteristics and standard JPEG （joint photographic experts group） compression, image re-ordering techniques are analyzed, and the method of modifying some blocks into single color blocks is adopted. Then, a suitable quantization table for cash images is obtained. Experimental results show that the method is effective.展开更多
The packing measure for a random re-ordering of the Cantor set, the packing dimension for the random set belonging to a sequence satisfying the Hausdorff and packing measures and packing measures for random subsets of...The packing measure for a random re-ordering of the Cantor set, the packing dimension for the random set belonging to a sequence satisfying the Hausdorff and packing measures and packing measures for random subsets of R belonging to a regular sequence have been obtained.展开更多
Image denoising is indispensable for image processing.In this paper,image denoising algorithm based on Nonlocal Means(NLM)filter is proposed.Recently,abundant enhancements based on NLM filter have been performed.Howev...Image denoising is indispensable for image processing.In this paper,image denoising algorithm based on Nonlocal Means(NLM)filter is proposed.Recently,abundant enhancements based on NLM filter have been performed.However,the performance of NLM filter is still inferior to that of other image processing approaches such as K-SVD.In this paper,NLM algorithm with weight refinement is utilized for image denoising.Weight refinement is performed to thoroughly take advantage of self-similarity of the image.Experimental results show good performance of the proposed method.展开更多
文摘One of the limitations of using OFDM technique is its higher PAPR in the time domain signal. The higher PAPR OFDM signal would cause the fatal degradation of BER performance and undesirable spectrum regrowth in the nonlinear channel. One of the promising PAPR reduction methods for OFDM signal is the Partial Transmit Sequence (PTS) method which can achieve better PAPR performance with reasonable computation complexity. However the PTS method is required to inform the phase coefficients of PTS as the side information to the receiver for the correct demodulation of data information through the data or separate channels. To simplify the transceiver of OFDM system with the PTS method, the phase coefficients of PTS are usually embedded in the data information. However since the phase coefficients of PTS are obtained after the PTS processing only for the data information at each OFDM symbol, it is hard to embed the phase coefficients of PTS in the data information separately without degradation of PAPR performance. To solve this problem, this paper proposes a new PAPR reduction method based on the packet-switched transmission systems in which all the clusters within the certain number of OFDM symbols have the sequential cluster ID numbers embedded in the header of each cluster. The salient features of the proposed method are to reduce the PAPR performance by re-ordering of clusters (ROC) in the frequency domain at the transmitter and to reconstruct the original ordering of clusters by using the cluster ID number demodulated from each cluster at the receiver. This paper also proposes a reduction technique of computation complexity for the proposed ROC method by using the feature of IFFT processing. This paper presents various computer simulation results to verify the effectiveness of the proposed ROC method with the reduction technique of computation complexity.
基金supported by the National Natural Science Foundation of China under Grant No. 60703087the Project of Science and Technology Department of Zhejiang Province under Grant No. 2010C31006 and No. 2011C21081
文摘In the field of economy, there are more and more electronic scanning cash images, which need to be compressed in a higher compression ratio. This paper proposes a specific compression algorithm for cash images. First, according to cash image characteristics and standard JPEG （joint photographic experts group） compression, image re-ordering techniques are analyzed, and the method of modifying some blocks into single color blocks is adopted. Then, a suitable quantization table for cash images is obtained. Experimental results show that the method is effective.
文摘The packing measure for a random re-ordering of the Cantor set, the packing dimension for the random set belonging to a sequence satisfying the Hausdorff and packing measures and packing measures for random subsets of R belonging to a regular sequence have been obtained.
基金supported by the MKE(The Ministry of Knowledge Economy),Korea,under the ITRC(Infor mation Technology Research Center)support programsupervised by the NIPA(National IT Industry Promotion Agency)(NIPA-2011-C1090-1111-0003)
文摘Image denoising is indispensable for image processing.In this paper,image denoising algorithm based on Nonlocal Means(NLM)filter is proposed.Recently,abundant enhancements based on NLM filter have been performed.However,the performance of NLM filter is still inferior to that of other image processing approaches such as K-SVD.In this paper,NLM algorithm with weight refinement is utilized for image denoising.Weight refinement is performed to thoroughly take advantage of self-similarity of the image.Experimental results show good performance of the proposed method.
