Underwater Targets Based On Time-frequency Analysis, Feature Extraction

This paper studies mainly on Wigner-Hough transform and S transform which is one method of the time frequency analysis, This paper studies mainly on the two methods in the underwater target echoes signal processing. Some real examples are presented in this article and they prove that this method is very effective in extracting the feature of underwater targets.The main work and originality in this paper can be summarized as below:1. Studies on the Wigner-Hough transform in the suppression of cross-components. A modified algorithm is presented based on reassignment Wigner-Hough transform and applied in underwater signal processing. This algorithm not only suppresses the cross-components but also has good performance in the low SNR.2. Studies on the S transform(ST) and realizes it. Compares the S transform with other traditional methods and understand the important performance of S transform.3. This thesis successfully applies S transform in underwater signal processing and studies on phase information of signah feature extraction of partial-spectram and the estimation of instantaneous-frequency signals.4. Design a classifier and testify the availability of the feature extraction method.5. Use the above classifier to classify target with the feature extracted from the warship signal and gain preferable effection.