• Journal of the Institute of Electronics Engineers of Korea SP
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• v.44 no.5
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• pp.94-102
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• 2007

In de-noising, it is wellknown that wavelet-thresholding algorithm shows near-optimal performances in the minimax sense. However, the wavelet-thresholding algorithm is difficult in realization it on hardware, such as FPGA, because of wavelet function complexity. In this paper, we present a new do-noising technique with the binary tree structured filter bank, which is based on the signal power ratio of each subbands to the total signal power. And we realize it on FPGA. For simple realization, the filter banks are designed by Hadamard transform coefficients. The simulation and hardware experimental results show that the performance of the proposed method is similar with that of soft thresholding de-noising algorithm based on wavelets, nevertheless it is simple.

• 전자공학회논문지 IE
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• v.46 no.4
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• pp.16-24
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• 2009

In this paper, we propose a new noise cancellation system for the NDIR based optical analyzer, that can measure various environmental air-pollution materials (CO, $SO_2$, NOx, etc.) in real-time. The sensed signals are contaminated by the different noise sources that measurement noise with high frequencies and the drift noise with the low frequencies. They can be eliminated by a pre-processing that considering their time-domian properties and by a post-processing that using sub-power ratios in subband structure. In the proposed method, the ore and pose-processing for noise cancelling are useful for hardware implementation of the NDIR based optical analyzer with a precision measuring.