基于广义S变换的图像局部时频分析

Local Time-frequency Analysis of Images Based on Generalized S-transform

非平稳信号具有良好的时频局部特性,但是使用一些常规的信号处理方法对其进行时频分析具有一定难度。为了解决这一难题,引入基于广义S变换的时频分析方法来进行一维和二维空间非平稳信号的时频分析。同时,为避开对图像直接进行S变换带来的大时间开销和运算难度,选用不同尺度的局部窗口将二维图像转化成一维信号进行处理,再分别利用基本S变换和时频分辨率可调的广义S变换进行算法仿真和时频分析。试验结果表明,广义S变换比基本S变换具有更灵活的时频聚焦性。

Although non-stable signals have some excellent local time-frequency properties,it is difficult to analyze their time-frequency properties by using some conventional signal processing methods.In order to solve these problems,a new time-frequency analysis approach based on generalized Stransform is introduced to non-stable signals processing in the 1-D and 2-D space.At the same time,in order to avoid the time complexities and computing difficulties in the direct 2-D S-transform,the images are put into a series of 1-D signals by choosing different scalable local time windows.Then,the algorithm simulation and time-frequency analysis are achieved through both basic S-transform and generalized S-transform that has an adjustable time-frequency reso-lution.At last,the results demonstrate that the generalized S-transform has more flexible time-frequency focusing property than S-transform.