Pretreatment for laser spot image in strong noise
强噪声条件下激光光斑图像预处理方法研究

To investigate the de-noise ways of the strongly polluted laser spot image, a wavelet domain median filter and a combined filter based on wavelet-threshold and mathematics morphology were applied to inhibit the strong noise of laser spot images; the image Signal to Noise Ratio (SNR) and the Root-Mean-Square Error (RMSE) and the image gray surface chart were selected to estimate the de-noising effect of the images. Compared with other image filters, experimental results show that the de-noising effect of the Wavelet domain median filter is better than spatial domain median filter; when image noise reduction is carried out with the continuum method, the improved SNR is about 1.34 times of the wavelet transform algorithm and 3.14 times of the median filter; the RMSE is about 0.81 times of the wavelet transform algorithm and 0.50 times of the median filter; moreover, when the SNR of the former laser spot image is lower, the advantage of inhibiting noise of this method is more obvious.