The present invention discloses a
laser absorption spectrum
signal denoising method based on improved local mean
decomposition, comprising: obtaining a standard amplitude and a standard second
harmonic signal, and obtaining the amplitude and the second
harmonic signal of the
laser absorption spectrum signal of the
trace gas to be measured x ( k ) ; respectively for the second
harmonic signal x ( k ) add two groups of
white noise with
equal size and opposite sign, perform local mean
decomposition on the two groups of signals after adding
white noise, and calculate the second harmonic signal according to the corresponding main factor component set x ( k ) corresponding to the main factor component set, from which useful main factor components are selected for reconstruction to obtain the second harmonic signal after
noise reduction y ( k ), calculate the second harmonic signal y ( k ), and then correct the
gas concentration corresponding to the
trace gas to be measured according to the standard amplitude and the amplitude of the
trace gas to be measured to obtain the corrected
gas concentration of the trace gas to be measured. The present invention can improve the detection accuracy and the
lower limit of measurement, and has a small amount of calculation, which is convenient for
engineering application.