Sheng wu yi xue gong cheng xue za zhi = Journal of biomedical engineering = Shengwu yixue gongchengxue zazhi
-
Sheng Wu Yi Xue Gong Cheng Xue Za Zhi · Oct 2006
[Dynamic analysis of heart rate variability based on wavelet transform].
The analysis of heart rate variability (HRV) has become a tool for noninvasively detecting the cardiovascular modulation of autonomic nervous system. Traditional analysis in frequency domain mainly includes calculating the power and detecting the peak frequency of each physiological frequency band. Whether employing the classical method or AR model to estimate the spectrum, the approximate stationarity of HRV is presupposed. ⋯ A dynamic analysis method based on wavelet transform was proposed in this paper, which not only can obtain the traditional indices in frequency domain, but can compute their dynamic values varying with time, called short-time power and short-time LF/HF ratio. The latter can dynamically evaluate the activity of autonomic nervous. Finally the method was applied to trace the balance of autonomic nervous in Atropin drag experiment.
-
Sheng Wu Yi Xue Gong Cheng Xue Za Zhi · Aug 2006
[Speaker identification based on Mel frequency cepstrum coefficient and complexity measure].
In present, the most basically used parameters for speaker identification are linear predictive coding (LPC) parameter, Mel frequency cepstrum coefficient(MFCC), etc. First in this paper only MFCC was used as the parameter and then Lempel-Ziv Complexity was combined with MFCC as parameters. The text-dependent recognition rate of 50 speakers increased from 42% to 80% and the text-independent recognition rate of 50 speakers increased from 60% to 72%. This test shows that Lempel-Ziv complexity, as a new parameter, can be applied to speaker identification.
-
Sheng Wu Yi Xue Gong Cheng Xue Za Zhi · Apr 2006
[A digital subtraction angiography system based on LUT algorithms].
Look-up table (LUT) algorithms have been widely used in digital signal processing, but the article on the application of LUT algorithms in digital subtraction angiography was rarely reported. In this article, the effect of different LUT algorithms on digital subtraction angiography images is introduced. The result reveals that different LUT algorithms can bring about different effects of image. Based on analysis and comparison, we deem it possible to acquire improved images of DSA by use of some LUT algorithms with image processing.
-
Sheng Wu Yi Xue Gong Cheng Xue Za Zhi · Apr 2006
[R-wave detection of ECG signal by using wavelet transform].
The detection of R-wave of ECG is essential to the analysis of the heart rate variability (HRV). In this paper, an R-wave detection method using wavelet transform(WT) is presented in line with the principle of discrete wavelet transform(DWT) and multi-resolution technique (MRT). ⋯ The results show that R-wave could be detected accurately and localized precisely by this method, even when the patient was seriously sick or the signal was disturbed by noise. Consequently the method has a quite high locating precision (its error is not more than two sampled points and about 85 percent of the points of R-wave in ECG signal are localized precisely) and the correct detection rate of R-wave is 99.8% by using wavelet transform, so this method is quite feasible.
-
Sheng Wu Yi Xue Gong Cheng Xue Za Zhi · Dec 2005
[A medical image fusion method based on fuzzy mathematics].
In this paper, a method based on fuzzy mathematics to fuse multimodality medical images was presented. The improved FCM algorithm was adopted to segment images, and automatic fuzzy redistribution algorithm to define the subject degree. 16 different combinations of image tissues and 16 context relations, 256 models altogether, were considered. The result showed that the method had the great ability of anti-error and anti-segmentation interference and had the characteristics of robustness, quickness, and accuracy.