基于时频脊线的瞬时频率特征提取

根据时频脊线所在的位置信息与信号瞬时频率的对应关系，提出根据时频脊线提取多成分瞬时频率的新方法。该方法是，先通过加窗处理对一维时间信号进行时域分段，对每个时段信号采用自适应核函数时频分析，再把每个时段上求得的时频分布拼接成信号整体时频谱；然后将时频分布图转换成直观的二维图像，进行平滑处理后采用二维Laplacian算子提取时频图像的脊线并作细化处理；采用Hough变换自动检测时频脊线的特征参数，特别对正弦调频信号和线性调频信号的时频脊线检测问题进行论述。仿真试验和齿轮故障诊断的工程实践证明了该方法的可行性和有效性。

Extraction of Instantaneous Frequency Characteristic Using Time-frequency Ridges

A novel multi-component instantaneous frequency (IF) extracting method using the corresponding relation between the position information of time-frequency ridges and IF of signal is introduced. After the redial Gaussian kernel time-frequency distribution (RGKD) is studied, the improved RGKD is proposed. By segmenting the one dimensional time signal in time domain by way of adding windows, the whole time series is cut into many sub-segments and the whole RGKD can be obtained by concatenating the sub-segment RGKD. Then, the whole RGKD is regarded as an image, and the ridges of the image are extracted by using digital image processing method including smoothing processing, two dimensional Laplacian operator and refining treatment. Hough transform for detecting lines automatically is used, especially, the process of detecting beeline and sine curve are discussed. The validity of the whole method has been verified by computer simulation and fault diagnosis in gear box.