Abstract: A method of detecting the number of driver’s operating hands on the steering wheel based on machine vision is proposed. The first step is to confirm the position of the steering wheel in one image and to calculate the dimension parameters of the steering wheel in the oval area so as to get the coordinates of certain point on the center line of the wheel oval. The second step is to extract the region-of-interest（ROI） with the size of 30×60 whose center is the point calculated above and to normalize the banked angle of the extracted ROI. After several preprocessing operations such as histogram equalization and binarization, the double-threshold determination method is used to judge whether hands exist or not in single ROI. And then the V-φ graph is drawn according to searching the whole area of the steering wheel in a particular step along the center line of the oval in anti-clockwise direction. Finally, the number of driver’s hands on the steering wheel is got by analyzing the V-φ graph.

Key words: safety driving assistant, steering wheel, operating hands, machine vision

摘要： 提出一种基于机器视觉检测方向盘上操作手数目的方法。首先确定图像中方向盘的位置，计算方向盘在椭圆区域的尺寸参数，进而获得方向盘椭圆形中心线上点的坐标，以此坐标点为中心截取30×60大小的窗口为感兴趣区域，并将截取的感兴趣区域倾斜角度作归一化处理。归一化之后的感兴趣区域经直方图均衡化和二值化等预处理操作后，利用双阈值判定法判断单一感兴趣区域中是否有类似手形存在，再以特定步长沿椭圆中心线按逆时针方向搜索全方向盘区域，根据方向盘的V-φ图形判断方向盘上的操作手数目。

关键词: 安全辅助驾驶, 方向盘, 操作手, 机器视觉