Characteristic peak extraction method for low signal-to-noise ratio ultraviolet Raman spectrum

Abstract

The invention discloses a characteristic peak extraction method for a low signal-to-noise ratio ultraviolet Raman spectrum, and belongs to the field of spectrum detection and spectrum processing technologies and signal processing. The method comprises the following steps of collecting ultraviolet Raman signals in real time, counting collected Raman signal data, and predicting the effective peak value of the Raman signals; processing each frame of collected Raman spectrum, for each frame of Raman spectrum, segmenting each frame of Raman spectrum into various block areas through the obtained effective valley, and respectively judging attributes of the segmented block areas; for each noise area, enabling each point to be equal to the minimum value of the area, and then splicing the Raman signal area and the processed noise area; splicing the processed N + 1 frames of spectrums along a time axis to form a 2D image, filtering the 2D image through an iterative bilateral filtering method, and superposing and normalizing the N + 1 spectrums along the time axis after filtering to obtain a clean Raman characteristic peak spectrum image.

Description

technical field The invention relates to a method for extracting characteristic peaks of ultraviolet Raman spectra with low signal-to-noise ratio, in particular to a method for obtaining clean and effective Raman characteristic peak images for real-time low signal-to-noise ratio ultraviolet Raman signals, which belongs to the spectrum Detection and spectral processing techniques as well as the field of signal processing. Background technique Raman spectroscopy is a non-destructive spectroscopic detection method based on inelastic light scattering (i.e., changes in the energy / frequency of the incident laser light) from laser-matter interactions. By measuring the specific Raman spectrum (Raman fingerprint) of the molecular system to be tested, the sample can be quickly, simply, and repeatably non-contact non-destructive testing and quantitative analysis, with short time required, small amount of sample, and accurate measurement results Features. However, the sensitivity of R...

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Problems solved by technology

However, the sensitivity of Raman spectroscopy detection is low (the intensity of Rayleigh scattered rays is only 10 of the incident light intensity. -3 , the Raman spectrum intensity is only about 10 of the Rayleigh line -3 ), especially for some small, portable or simple ultraviolet Raman spectroscopy detection systems, due to factors such as low laser power, insufficient laser stability, and too much noise of the uncooled CCD, the noise of the detection results is greatly affected, and the Raman signal signal Low noise ratio, difficult to identify Raman characteristic peaks

Some traditional signal processing methods can remove some random noise, so that the Raman characteristic peaks are prominent, but it is not necessarily ideal for Raman spectroscopy, because many weak Raman peaks, whether in terms of amplitude or waveform, close to noise

Therefore, in the process of removing random noise, many weak Raman effective signals will be lost, and the signal-to-noise ratio has not improved much

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