三线结构光视觉传感器现场标定方法

Field calibration method for three-line structured light vision sensor

三线结构光视觉传感器由于获取信息量大、测量速度快等特点被广泛应用于工业现场测量。为了实现传感器高精度、快速的现场标定,提出了一种基于支持向量机的三线结构光视觉传感器标定方法。首先,设计标定靶标;其次,采集靶标图像后提取特征点亚像素坐标值;再次,基于支持向量机方法建立特征点的图像坐标和三维空间坐标的映射模型;最后,将待标定点图像坐标输入映射模型,即可得到三维空间坐标,实现对三线结构光视觉传感器的直接标定。实验验证,Y轴、Z轴方向上的测量绝对误差均值分别为0.021 1 mm和0.015 0 mm,具有较高的标定精度,且该标定方法标定过程简单、快速,适合现场标定。

The three-line structured light vision sensor is widely used in industrial field measurement due to it has many advantages such as speedy and abundant information. In order to calibrate the three-line structured light vision sensor on-field with high accuracy and high efficiency, a new calibration method based on support vector machine was proposed. Firstly, a calibration target was designed. Secondly,calibration images were captured and feature points were identified. And then sub-pixel coordinates of feature points were extracted. Thirdly, a direct mapping model according to image coordinates and three dimension coordinates of feature points was built based on support vector machine. Finally, image coordinates of the calibration points were put into the model and their three dimension coordinates could be obtained. So the three-line structured light vision sensor could be calibrated directly. Experimental results demonstrated that this direct calibration method had high accuracy; its mean absolute error was 0.021 1 mm in Y direction and 0.0150 mm in Z direction. It concludes that this method is easy, fast and suitable for field calibration.