双线阵无透镜超分辨率扫描成像方法研究

Research on Super-Resolution Scanning Imaging Method for Lensless with Dual-Line Array

针对无透镜成像系统分辨率低和单线阵扫描成像中由于细胞流速不准确造成的图像重构畸变问题,本文提出了一种基于双线阵图像传感器的超分辨率扫描成像方法.通过引入第二个线阵,利用双线阵的时间空间关系,实现了细胞流动速度的实时测量,为扫描图像的重构提供了精准参数.综合考虑了光源、衍射光路、细胞样品瞬态流速、图像传感器像素尺寸、倾斜角度和帧频等系统特性,建立了线阵扫描成像系统的成像模型,深入分析了影响双线阵成像质量的因素,建立了基于坐标变换、扫描图像插值计算的双线阵扫描成像系统的图像重构模型.综合两种模型,以条形图案为仿真对象,分析了该方法的成像特性,并从理论上验证了双线阵扫描成像系统的可行性和有效性.仿真结果表明,双线阵扫描成像系统的空间分辨率相比面阵系统至少提升了2.8倍,并且结构相似性和峰值信噪比均有5%~15%的提升.在此基础上,搭建了双线阵扫描成像系统,并以微球、红细胞和白细胞作为测试对象,对系统进行了实际测试.结果表明,双线阵扫描成像系统解决了单线阵扫描成像图像重构畸变的问题,同时相比面阵成像系统,20μm微球的直径均值误差为2.04%,红细胞和白细胞的特征更多、更明显.

Aiming at the problems of the low resolution in lensless imaging systems and the reconstruction distortion in single-line array scanning imaging systems,a super-resolution scanning imaging method is proposed for lensless using a dual-line array image sensor.The cell’s velocity can be measured in real-time using the space-time displacement of the du⁃al-line array,which provides accurate parameters for the reconstruction.Considering the system characteristics of optical wavelength,diffraction light path,cell sample flow rate,pixel size of the image sensor,tilt angle,and frame rate,the scan⁃ning imaging model of the scanning imaging system is established.The factors affecting the imaging quality of the dual-line array are analyzed,and the image reconstruction model of the dual-line array scanning imaging system is established by co⁃ordinate transformation and scanned image interpolation calculation.By synthesizing the two models and taking the strip pattern as the simulation object,the imaging characteristics are analyzed,and the feasibility and effectiveness of the dualline array scanning imaging system are verified theoretically.The simulation results show that the spatial resolution of the scanning imaging system with a dual-line array is at least 2.8 times higher than that of the system with an area array,and the SSIM and PSNR are improved by 5%~15%.On this basis,a scanning imaging system for lensless with a dual-line array was built,and the microspheres,red blood cells,and white blood cells were used as test objects to test the system.The re⁃sults show that the problems of the reconstruction distortion in single-line array scanning imaging systems can be solved with a dual-line array scanning imaging.The mean diameter error of 20μm microsphere is 2.04%between the scanning im⁃aging system with dual-line array and the area array imaging system,and the characteristics of red blood cells and white blood cells are more obvious under the scanning imaging system with the dual-line array.