Research On Construction Of Scattering Spectrometer System And Spectral Reconstruction Method

The traditional optical imaging techniques which based on “light travels in straight lines” fail to image the target because of the scattering of light passing through ground glass,haze and tissues.To solve this problem,methods such as wavefront modulation,image reconstruction,speckle correlation and deconvolution have been proposed.However,all these studies devote to solving the problem of obtaining two-dimensional spatial information of targets in strong scattering environment,and there is few research on the problem of simultaneously acquiring spectral radiation characteristics of a target.Accordingly,this work focuses on the scattering spectral resolution system and spectral reconstruction algorithm which can be combined with the existing scattering imaging methods,and the specific research contents include spectral speckle formation and spectral characteristics,theoretical modeling of scattering spectrometer,spectral reconstruction algorithm and experimental results analysis.Starting with the phenomenon of scattering and the formation of spectral speckles,the distribution of speckle in the reflection and transmission optical paths of free space propagation is introduced.In addition,the inequality relation between the correlation of speckles and wavelength variation is further deduced according to the spectral characteristics of the distribution of speckles.On this basis,compared with the traditional spectrometer spectral principle and resolution calculation method,the spectral model based on spectrum to space mapping and spectral correlation function of scattering spectrometer are introduced.Based on the phase delay characteristics of scattering medium and the spectrum to space mapping theory of scattering spectrometer,the theoretical model for spectrum measurement is constructed,and the spectrum transmission matrix is calibrated by numerical simulation.Then,the method proposed in this paper realizes the spectral measurement of the incident light wave after the correctness of the simulation model is verified by combining the spectral reconstruction algorithm and the nonlinear optimization algorithm.Relying on the above theoretical model,ground glass of different particle sizes is selected as the light splitting element to construct the optical system of the scattering spectrometer.Firstly,the optical properties of the ground glass are analyzed,and the experimental results show that the average free path of the ground glass decreases with the increase of particle size,thus the scattering ability decreases.Secondly,the mapping speckles of narrow and wide spectrum light source are obtained by using the scattering spectrometer experimental system,and the spectral reconstruction process can be completed combined with spectral reconstruction and optimization algorithms.Finally,the polarization characteristics,spectral resolution,spectral reconstruction error and anti-noise performance of the system are analyzed.The experimental results show that the scattering spectrometer system and the spectral reconstruction method can realize the measurement of the spectrum of the incident light wave by using the spectral characteristics of the scattering medium.The research of the scattering spectrometer system and the spectral reconstruction algorithm can be used as a supplement to the existing scattering imaging technology.At the same time of imaging through scattering medium,the acquisition of target spectral characteristics can further improve the recognition and detection ability of targets with similar contours,and greatly expand the application field for scattering imaging technology.