Abstract: Monitoring and analyzing the fatigue and attention state by using the machine vision is one of hotspots in the assistant safe driving system.Calculating driver face orientation angle is the precondition of analyzing attention state of drivers.The idea of face and face organ location is introduced firstly and the techniques for driver face orientation in this system are discussed mostly.Based on analyzing the rotary motion of the head，an algorithm for calculating the facial rotary angle of drivers is proposed.Practice proves that the algorithm proposes acts in real time and obtains excellent effect，which lays a good foundation for further information-collecting and analyzing of the driver’s attention state.

摘要： 利用机器视觉对驾驶人疲劳状态及注意力状态进行监测和分析是安全辅助驾驶领域内的研究热点之一，而对驾驶人面部朝向角度进行计算则是注意力状态分析的前提条件。首先介绍了驾驶人面部及面部器官定位的思路，然后重点讨论了驾驶人面部朝向的技术环节，在对人体头部旋转运动的分析基础上，提出了计算驾驶人面部旋转角度的计算方法。实践证明，采用的处理算法实时性好，准确率较高，效果非常理想，为下一步的驾驶人注意力状态分析及相关信息提取打下了良好的基础。