Denoising method using empirical mode decomposition with switchable interval threshold for lidar signals

Using the empirical mode decomposition direct threshold (EMD-DT) and empirical mode decomposition interval threshold (EMD-IT) to de-noise lidar return signals, aiming to solve the problem of mode-mixing, a method of EMD switch interval threshold (EMD-SIT) is applied. Firstly, the signal is processed by the use of EMD. Then the decomposed intrinsic mode functions (IMF) with noise are removed by zero-crossing rate method. Finally ,by the use of the zero-crossing threshold, a switch interval threshold is obtained, which combines the EMD-IT and EMD-DT to de-noise the noise signals. The comparisons of different thresholds and the de-noise experiment of lidar shows that noise can be removed effectively by the proposed method, meantime the mode mixing is restrained. Compared with EMD-DT and EMD-IT methods, EMD-SIT method has more advantages Therefore ,the demonstrated method has a promising future.