分波段照明法实现单透镜大景深成像

基于透镜色散原理,提出了运用分波段照明法扩大单透镜成像景深的方法.理论推导出物距和照明光波长之间存在正相关关系,据此选择相应波段的照明光源,通过照明光学设计,使不同物距的物体均能清晰成像在同一像面上.ZEMAX软件模拟结果与理论分析吻合.采用自行设计的图像采集系统,只用一个35mm焦距普通双凸透镜进行实验测试.人眼主观和专业软件测试结果均表明:采用分波段照明方式比用白光照明景深扩大81.8%,分辨率最大提升200.3%;比只用单色光照明景深扩大了93.6%,分辨率最大提升189.7%.

Large Depth of Field Imaging Technology of Single-lens Based on Discrete Spectral Illumination

To enlarge the depth of field of single-lens system,discrete spectral illumination approach based on imaging dispersion was proposed.Firstly,the relation between object distance and illuminating wavelength were theoretically derived.Next,numerical simulation using ZEMAX indicates high-resolution images at various focal planes was obtained via an optimized illumination system with corresponding spectral light sources,and the simulation results were consistent with the theoretical analysis.Finally,an image acquisition system using biconvex lens was designed for practical measurement,and a biconvex len with focus of 35 mm was used to experiment.The results show that compared to monochromatic illumination and white light,the depth of field of proposed method is increased respectively by 93.6% and 81.8%,and the resolution ratio is improved by 189.7% and 200.3%.