光子学报, 2018, 47 (7): 0715002, 网络出版: 2018-09-16
基于正弦相位编码的相机离焦标定
Defocus Camera Calibration Based on Sinusoidal Phase Coding
相机标定 离焦 相位匹配 相移法 摄影设备 Camera calibration Defocusing Phase matching Phase shift Photographic equipment
摘要
分析了光学系统离焦状态对基于正弦光栅的结构光相位的影响.基于正弦结构光相位与相机对焦状态无关的性质, 提出了一种利用相移法正弦结构光编码显示面板对离焦相机进行标定的方法.使用Floyd-Steinberg Dithering算法消除了显示面板gamma变换带来的结构光相位计算误差.实现了相机在离焦状态下对标定物特征点的准确提取.标定结果重投影误差为0.17 pixels.相机焦距的标定误差在0.39%以内.与传统方法相比提高了标定精度, 为具有特殊成像范围的相机的标定提供了一种解决方案.
Abstract
The influence of the defocus state of the optical system on the phase of structured light based on sine grating, abbreviated as sinusoidal structured light, was analyzed. Based on the property that the sinusoidal structured light phase is independent of the camera's focusing state, a method of calibrating the camera in the defocus state using a phase-shifted sinusoidal-structured-light-encoded display panel is proposed. The Floyd-Steinberg Dithering algorithm is used to eliminate the structured light phase calculation errors caused by the gamma conversion of the display panel. This method makes the accurate extraction of the feature points of the calibration object under the defocus state come true. The calibration result has a reprojection error of 0.17 pixels. The calibration error of the camera focal length is within 0.39%. The calibration accuracy was improved compared to traditional methods. A solution for the calibration of cameras with a special imaging range was provided.
杨浩, 蔡宁, 林斌, 曹向群. 基于正弦相位编码的相机离焦标定[J]. 光子学报, 2018, 47(7): 0715002. YANG Hao, CAI Ning, LIN Bin, CAO Xiang-qun. Defocus Camera Calibration Based on Sinusoidal Phase Coding[J]. ACTA PHOTONICA SINICA, 2018, 47(7): 0715002.