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目的目前对线阵相机的几何参数标定方法比较少,而且已有标定方法都需要特殊、高精度要求的设备,为此提出一种基于二轴转台测角法的线阵相机标定方法,通过简单的设备高精度求取线阵相机的内参数和畸变参数。方法通过简化面阵相机成像模型,建立线阵相机成像模型且推导出参数计算公式,提出测角法标定流程并设计了专门的标定板,利用图像边缘检测得到标定板黑白条纹的边缘点坐标,结合二轴转台的角度信息,代入成像模型中,主要采用最小二乘法和迭代优化算法,求取线阵相机的内参和畸变参数。同时指出了该方法的适用性和标定精度依赖于转台精度、镜头视场角和感光器件分辨率。结果对3只不同焦距的镜头进行标定实验,分析了内参数和畸变参数迭代优化过程,焦距的标定精度优于5μm、主点的标定精度优于3μm,与其他文献中高成本方法进行相比,处于同一数量级。结论提出一种新的线阵相机几何参数标定方法,该方法利用低成本二轴转台和黑白条纹标定板即可高精度标定出线阵相机几何参数。该方法的适用性依赖转台精度、镜头视场角和感光器件分辨率,对于步长为0.012 9°的转台和分辨率为1 436的线阵相机,最多只能标定焦距为16 mm的镜头,而焦距更长的镜头需要更高精度的转台。
Aim At present, there are few methods to calibrate the geometrical parameters of the line array camera, and the existing calibration methods require special and high-precision equipment. Therefore, a calibration method based on two-axis turntable angle measurement method is proposed. Of the equipment to obtain high-precision linear array camera internal parameters and distortion parameters. Methods By simplifying the imaging model of plane array camera, the imaging model of linear camera was established and the formula of parameter calculation was deduced. The calibration procedure of angle measurement method was proposed and a special calibration plate was designed. Edge coordinates of black and white stripes of calibration plate were obtained by image edge detection. Combined with the angle information of two-axis turntable, into the imaging model, the least square method and iterative optimization algorithm are mainly used to obtain the internal parameters and distortion parameters of the line camera. At the same time, it is pointed out that the applicability and calibration accuracy of this method depend on the accuracy of rotary table, the angle of view of the lens and the resolution of the photosensitive device. Results The calibration experiments of three lenses with different focal lengths were carried out. The iterative optimization of internal parameters and distortion parameters were analyzed. The calibration accuracy of the focal length was better than 5μm and the calibration accuracy of the main point was better than 3μm. Compared with other high cost methods, In the same order of magnitude. Conclusion A new calibration method of linear array camera geometry parameters is proposed. The method can accurately calibrate the line array camera geometric parameters by using low-cost two-axis turntable and black-and-white stripe calibration plate. The applicability of this method depends on the accuracy of the turret, the field of view of the lens and the resolution of the sensor. For a turntable with a step size of 0.012 9 ° and a line camera with a resolution of 1 436, only up to 16 mm focal length can be calibrated, The longer focal length lens requires a more accurate turntable.