基于自校验的单像素成像系统动态干扰去除方法

Dynamic occlusion removal in single-pixel imaging system based on self-check

单像素成像系统通过对目标场景的多次调制,获取相应的单像素测量值,并由此重构图像.在这一过程中,如果其他物体侵入成像场景,会严重影响测量值的准确性,降低重构图像质量.由于侵入物体的反射率,形态均具有一定的随机性,因此从桶探测器信号的角度很难有效分离出受干扰信号.针对这一问题,基于哈达玛矩阵的特征,提出了一套自校验方法,即利用桶探测器自身测量值进行正确性校验,筛选出未受干扰的桶探测器信号,显著提升了重构图像的质量.该方法适用于一般性成像场景,且不需要引入额外的调制图像辅助校验,有力推动了单像素成像技术的实用化进程.

Single-pixel imaging(SPI)system modulates the object with a series of patterns,records the corresponding measurements of a bucket detector and forms an image by the algorithm of compressed sensing.In this process,if other objects enter into the field of view of SPI,the accuracy of measurement will be seriously affected,and the quality of the reconstructed image will decrease.Owing to the randomness of the reflectivity and shape of the occlusion,it is difficult to effectively separate the disturbed part from the bucket detector signal.To solve this problem,we propose a self-check method based on the characteristics of Hadamard matrix,that is,using the measurement values of bucket detector to verify the correctness of signal.Usually when using the Hadamard matrix as the measurement matrix in SPI,it is divided into complementary positive pattern and negative pattern.The measurements of these two patterns are subtracted to form the image(the difference value marked by l).Owing to the complementarity of the two patterns,the sum of the corresponding measurements should be a constant(marked by u).When dynamic occlusion appears,the value of u will fluctuate significantly,so we choose u as the standard to judge whether an occlusion appears.In order to reduce the influence of other factors(such as system noise or fluctuation of the illumination)in the imaging process,we further propose a dynamic occlusion removal method based on the statistical histogram of the values of u.We first find the position of the maximum value in the histogram,and then expand from this position to both sides of the histogram.We calculate the area of the expanded region,and stop the expansion when this area is greater than the threshold.Then the l corresponding to u in the expanded region is the measured value without interference.Experiments show that this method can retain the undisturbed signals of the bucket detector and significantly improve the quality of the reconstructed image.This method is simple and effective,and it is also suitable for general imaging scenes.More importantly,it does not need to introduce additional patterns for verification,which effectively promotes the practical process of single pixel imaging technology.