红外与激光工程, 2019, 48(2): 0218003, 网络出版: 2019-04-05
Design of focused light field computational imaging system with four-types focal lengths
光场相机 景深 有效分辨率比率 多焦距 微透镜阵列 light field camera depth of field effective resolution ratio multi-focus microlens array
光场相机是一种在图像传感器前增加微透镜阵列的新型相机结构, 除了记录不同位置下光的强度及颜色外, 也记录不同位置下光线的方向信息, 从而能够计算目标场景的深度图和高阶相位图。该技术由于景深和分辨率相互制约, 获得大景深时分辨率会降低。分析了其结构特点并推导了景深和分辨率的关系, 并就选定的设计参数绘制了变化曲线。在此基础上, 提出了一种新型光场相机的设计方法, 该结构基于具有四类焦距的微透镜阵列, 可获得超大景深, 同时将分辨率的下降程度控制在可接受范围。仿真结果表明: 相对于三类焦距微透镜阵列, 所设计的四类焦距微透镜阵列景深可提高三倍, 而分辨率达到普通相机的18.9%。
The light field camera is a new camera structure that put a microlens array in front of image sensor. It can not only record the intensity and color of light at different positions, but also record the direction information of light in different positions, so that the depth map and high-order phase map of the target scene can be calculated. This technology is limited by the depth of field and resolution, and the resolution is reduced when a large depth of field is achieved. Its structural characteristics were analyzed and the relationship between the depth of field and the resolution was derived, and the change curves were ploted for selected design parameters. Based on this, a design method of a novel light field camera based on a microlens array with four types of focal lengths was proposed, which can obtain large depth of field and control the decline degree of resolution in an acceptable range. The simulation results show that compared with the three types of focal length microlens arrays, the depth of field of the four types of focal length microlens arrays designed can be increased three times, and the resolution can reach 18.9% of the ordinary cameras.