激光光幕破片测速信号的特征点检测方法

Peak Detection of Fragments Velocity Measurement in Laser Screen

激光光幕破片测速系统中,破片过靶信号穿过激光光幕时特征点时刻检测的准确度影响测速的准确度与精度.针对传统的特征点检测方法中对信号直接进行数值微分会误检测起伏较大的噪声点、峰值检测会受噪声影响而引起信号误判的问题,提出了基于小波变换的模极大值特征点检测法.该算法利用小波模极大值和尺度、李氏指数与破片信号的奇异性之间的关系,选取合适的小波基对破片信号进行小波模极大值处理,从而实现特征点检测与去噪,可以准确识别破片,并检测到其特征点时刻.经大量测试数据处理表明,小波模极大值法检测破片识别率为96.9%,相比传统峰值检测法,提高了特征点检测的准确率.

In laser screen fragments velocity measurement system,the accurate time of the fragment across the laser screen affects the velocity precision.The traditional peak detection using numerical differentiation of signal directly can cause the wrong detection of the noises,and the direct peak-detection method can cause signal error detection because of effects of noises also.A method of the peak detection based on wavelet transformed modulus maximum is proposed.Firstly appropriate wavelet basis is selected and used to wavelet transform of fragment signal.Secondly peak detection and denoising is realized based on the relationship of wavelet modulus maxima,Lipschitz exponent and singularity of fragment signal.Peaks can be detected by the method of the wavelet transform modulus maxima method correctly.The 96.9%recognition rate of fragments can be obtained by using the method through a large number of test data processing.