We proposed and experimentally demonstrate a calibration method to estimate the position and the orientation of the anisotropic near point LED light source from a single view. In this work, a Lambertian sphere is used as the calibration target, where the reflection model of the Lambertian sphere under the illumination of LED with given radiant intensity distribution is analyzed theoretically to establish the relationship between the recorded image intensity and the observed surface. Based on this relationship, the geometrical principle of the calibration is researched and an iteration method is presented to calculate the LED position and orientation with a cost function through minimizing the estimation error. The accuracy of the proposed method is verified by simulations with the mean estimation error lower than 5.8mm and 1.7deg for near field lighting. The experiments are performed by measuring the plaster models using the presented system, which proves the effectiveness of the proposed calibration approach.

我们提出并通过实验证明了一种校准方法，可以从单个视图估计各向异性近点 LED 光源的位置和方向。本工作以朗伯球体作为标定目标，从理论上分析了给定辐射强度分布的LED照射下朗伯球体的反射模型，建立了所记录图像强度与观测表面的关系。基于这种关系，研究了校准的几何原理，提出了一种迭代方法，通过最小化估计误差来计算具有成本函数的LED位置和方向。通过仿真验证了所提出方法的准确性，平均估计误差低于5.8mm和1。7deg 用于近场照明。实验是通过使用所提出的系统测量石膏模型来进行的，这证明了所提出的校准方法的有效性。