| Ghost imaging,as a novel imaging technology,can recover the information of unknown objects non-locally by correlating the light field.Due to its advantages such as object image separation,strong anti-interference ability,and super-resolution imaging,it has attracted more and more researchers’ attention.In the practical application of ghost imaging,the result of ghost imaging of reflective objects with rough surfaces will be seriously degraded compared with reflective objects with smooth surfaces.Since most objects in practical applications are reflective objects with rough surfaces,it is of extremely important practical significance to find a method to improve the imaging quality of reflective objects with rough surfaces.Aiming at this problem,this paper studies the influence of different modulated light sources on ghost imaging of reflective objects with rough surfaces in detail.The main research contents include:1.A scheme for ghost imaging of rough reflective objects using Hadamard modulated light source is proposed.Compared with the Gaussian random modulation light source,the imaging signal-to-noise ratio under the Hadamard modulation light source can be greatly improved.The imaging principle of reflective objects with rough surfaces under Hadamard modulated light source and Gaussian random light source is theoretically deduced.It is found that Hadamard has no background,and the fundamental reason is that the correlation coefficient of Hadamard matrix is 0,so that the corresponding light field,measured each time,hardly carries redundant noise information.Next,we experimentally compared the effects of roughness and reflection angle on imaging quality under different modulated light sources.The results show that Hadamard modulated light source is less sensitive to roughness than Gaussian random light source,and can significantly improve the imaging signal-to-noise ratio of reflective objects with rough surfaces.In addition,although the change of reflection angle affects the signal-to-noise ratio of imaging,the Hadamard modulated light source is more easily affected than the Gaussian random light source under the same conditions.2.Aiming at the obvious problem of rasterization in Hadamard imaging results,a scheme is proposed to use orthogonal modulated light source to improve it.Here,a new light source that is insensitive to roughness and can overcome the problem of Hadamard modulated light source needs to be found.By comparing several different modulated light sources,it is noted that the orthogonalization of Gaussian random light source and Hadamard modulated light source can significantly improve the signal-to-noise ratio of imaging and show good noise immunity.Then,comparing the influence of the roughness on the imaging quality between the orthogonalized modulated light source and Hadamard modulated light source,it is shown that both the orthogonalized modulated light source and the Hadamard modulated light source have good stability to roughness,while the orthogonalized modulated light source rasterization does not occur.In the exploration of the orthogonalized modulated light source and Hadamard modulated light source,we also discover that under undersampling,as the number of samples decreases,the Hadamard modulated light source will have more and more artifacts,but the orthogonalized modulated light source doesn’t.Therefore,compared with the Hadamard modulated light source,the orthogonalized modulated light source is more advantageous under certain circumstances.This paper analyzes the influence of different modulated light sources on the imaging performance of reflective objects with rough surfaces,which has a certain reference value for improving the imaging quality of reflective objects with rough surfaces in practical applications.In the case that the reflection object with rough surface is difficult to be distinguished by the traditional ghost imaging light source,using different modulated light sources to recover the object information provides a better choice. |
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