A new feature extraction method based on 2D-hidden Markov model（HMM） is proposed. Meanwhile the time index and frequency index are introduced to represent the new features. The new feature extraction strategy is tes...A new feature extraction method based on 2D-hidden Markov model（HMM） is proposed. Meanwhile the time index and frequency index are introduced to represent the new features. The new feature extraction strategy is tested by the experimental data that collected from Bently rotor experiment system. The results show that this methodology is very effective to extract the feature of vibration signals in the rotor speed-up course and can be extended to other non-stationary signal analysis fields in the future.展开更多
One-dimensional Mel-Frequency Cepstrum Coefficients (1D-MFCC) in conjunction with a power spectrum analysis method is usually used as a feature extraction in a speaker identification system. However, as this one dimen...One-dimensional Mel-Frequency Cepstrum Coefficients (1D-MFCC) in conjunction with a power spectrum analysis method is usually used as a feature extraction in a speaker identification system. However, as this one dimensional feature extraction subsystem shows low recognition rate for identifying an utterance speech signal under harsh noise conditions, we have developed a speaker identification system based on two-dimensional Bispectrum data that was theoretically more robust to the addition of Gaussian noise. As the processing sequence of ID-MFCC method could not be directly used for processing the two-dimensional Bispectrum data, in this paper we proposed a 2D-MFCC method as an extension of the 1D-MFCC method and the optimization of the 2D filter design using Genetic Algorithms. By using the 2D-MFCC method with the Bispectrum analysis method as the feature extraction technique, we then used Hidden Markov Model as the pattern classifier. In this paper, we have experimentally shows our developed methods for identifying an utterance speech signal buried with various levels of noise. Experimental result shows that the 2D-MFCC method without GA optimization has a comparable high recognition rate with that of 1D-MFCC method for utterance signal without noise addition. However, when the utterance signal is buried with Gaussian noises, the developed 2D-MFCC shows higher recognition capability, especially, when the 2D-MFCC optimized by Genetics Algorithms is utilized.展开更多
图片自动语义标注是基于内容图像检索中很重要且很有挑战性的工作。本文提出了一种基于Boosting学习的图片自动语义标注方法,建立了一个图片语义标注系统BLIR(boosting for lingu istic indexing im age retrievalsystem)。假设一组具...图片自动语义标注是基于内容图像检索中很重要且很有挑战性的工作。本文提出了一种基于Boosting学习的图片自动语义标注方法,建立了一个图片语义标注系统BLIR(boosting for lingu istic indexing im age retrievalsystem)。假设一组具有同一语义的图像能够用一个由一组特征组合而成的视觉模型来表示。2D-MHMM(2维多分辨率隐马尔科夫模型)实际上就是一种颜色和纹理特殊组合的模板。BLIR系统首先生成大量的2D-MHMM模型,然后用Boosting算法来实现关键词与2D-MHMM模型的关联。在一个包含60 000张图像的图库上实现并测试了这个系统。结果表明,对这些测试图像,BLIR方法比其他方法具有更高的检索正确率。展开更多
基金This project is supported by National Natural Science Foundation of China(No.50075079).
文摘A new feature extraction method based on 2D-hidden Markov model（HMM） is proposed. Meanwhile the time index and frequency index are introduced to represent the new features. The new feature extraction strategy is tested by the experimental data that collected from Bently rotor experiment system. The results show that this methodology is very effective to extract the feature of vibration signals in the rotor speed-up course and can be extended to other non-stationary signal analysis fields in the future.
文摘One-dimensional Mel-Frequency Cepstrum Coefficients (1D-MFCC) in conjunction with a power spectrum analysis method is usually used as a feature extraction in a speaker identification system. However, as this one dimensional feature extraction subsystem shows low recognition rate for identifying an utterance speech signal under harsh noise conditions, we have developed a speaker identification system based on two-dimensional Bispectrum data that was theoretically more robust to the addition of Gaussian noise. As the processing sequence of ID-MFCC method could not be directly used for processing the two-dimensional Bispectrum data, in this paper we proposed a 2D-MFCC method as an extension of the 1D-MFCC method and the optimization of the 2D filter design using Genetic Algorithms. By using the 2D-MFCC method with the Bispectrum analysis method as the feature extraction technique, we then used Hidden Markov Model as the pattern classifier. In this paper, we have experimentally shows our developed methods for identifying an utterance speech signal buried with various levels of noise. Experimental result shows that the 2D-MFCC method without GA optimization has a comparable high recognition rate with that of 1D-MFCC method for utterance signal without noise addition. However, when the utterance signal is buried with Gaussian noises, the developed 2D-MFCC shows higher recognition capability, especially, when the 2D-MFCC optimized by Genetics Algorithms is utilized.
文摘图片自动语义标注是基于内容图像检索中很重要且很有挑战性的工作。本文提出了一种基于Boosting学习的图片自动语义标注方法,建立了一个图片语义标注系统BLIR(boosting for lingu istic indexing im age retrievalsystem)。假设一组具有同一语义的图像能够用一个由一组特征组合而成的视觉模型来表示。2D-MHMM(2维多分辨率隐马尔科夫模型)实际上就是一种颜色和纹理特殊组合的模板。BLIR系统首先生成大量的2D-MHMM模型,然后用Boosting算法来实现关键词与2D-MHMM模型的关联。在一个包含60 000张图像的图库上实现并测试了这个系统。结果表明,对这些测试图像,BLIR方法比其他方法具有更高的检索正确率。
