中文摘要：

目的光场相机因其具有先拍照后对焦的能力而备受广泛关注,然而光场相机的理论研究往往受制于原始光场图像及其标定参数的获取。基于目前市面上唯一的一款消费级光场相机——Lytro相机,提出一套光场图像获取、校正和重对焦的系统化方法。方法通过分析Lytro相机工作原理、算法和文件结构,给出了一套实现原始光场数据提取、解码、颜色校正、微透镜阵列标定和校正的完整方案。并在此基础上提出一种基于分数阶傅里叶变换的Lytro相机重对焦方法。结果实验结果表明所提系统级方案正确,所提重对焦方法具有令人满意的重对焦性能。结论本文Lytro相机光场图像获取和标定方法,利用分数阶傅里叶变换实现光场图像的频率域重聚焦。基于两台Lytro相机的实验结果表明,本文方法可正确获取图像数据及相机参数,重聚焦算法效果好。

英文摘要：

Objective The light field camera has aroused more attention for its ability to refocus after the fact. However,researches of light field camera are often restricted by the acquisition of raw image and calibration parameters. Based on the Lytro camera,which is the only off-the-shelf light field camera for ordinary consumers,this paper develops systematical methods for acquisition of light field images,correction,and refocusing. Method By analyzing the operating principle,algorithms and file structure of the Lytro camera,we present a set of complete schemes that accomplish the data extraction from raw light field,decoding,color correction,calibration and correction for microlens array. Furthermore,based on fractional Fourier transform,a refocus method for light field images is proposed. Result Experiments demonstrate that our systematical scheme is feasible and correct,and the refocus method has satisfactory performance. Conclusion This paper presents the methods for acquisition and calibration of light field images and then implements the refocusing in frequency domain by using the fractional Fourier transform. Experimental results from two Lytro cameras verify that our proposed method can correctly obtain the image data and camera parameters,and the refocusing algorithm exhibits better performance.