Abstract: A partitioned calibration approach was applied to electronic whiteboard based on machine vision, since its location error distribution on large screens was non-homogeneous. Based on Human Interface Device (HID)'s implementation, the specific computer software was developed and the communication between the computer and electronic whiteboard was established. Configuration of calibration points on the whiteboard, receiving coordinates of these points, and calculation of calibration coefficients were completed. Thus the whole system calibration was implemented. The experimental results indicate that after calibration, the location accuracy is about 1.2mm on average on electronic whiteboard with the size of 140cm×105cm. And basic touch operations are accurately performed on the electronic whiteboard prototype after calibration.

Key words: electronic whiteboard, machine vision, calibration, mapping, perspective projection, partition

摘要： 针对基于机器视觉的电子白板屏幕较大、目标识别误差分布不均的特点,选用了一种分块校准方法进行系统校准。在完成了人机交互设备(HID)实现的基础上,进行了上位机软件的开发。建立了上位机与电子白板间的通信,完成了校准点设置、坐标接收和校准系数的计算,实现了电子白板的校准。测试结果表明:经过校准后,在140cm×105cm的大面积白板上,目标识别平均精度可达1.2mm。经过校准后的电子白板样机能精准地完成基本的触控操作。

关键词: 电子白板, 机器视觉, 校准, 映射, 透视投影, 分块