应用图像处理技术进行野外火车钢轨测量实验时，不可避免遇到外界强太阳光的干扰问题。为了能有效消除太阳光的干扰作用，采用了激光锁定成像的方法，通过外接控制电路触发激光器并让电荷耦合器件同步采集图像，运用激光锁定成像原理，获得高质量的钢轨轮廓曲线。通过大量实验验证，激光锁定成像的应用使得钢轨磨耗输出的结果更稳定，而且能够适应较大范围内变化的外界环境光干扰。结果表明，激光锁定成像能保证测量系统的稳定性，从根本上消除测量过程中出现的各种随机误差。

When the rail wear measurement is carried out in the wild, the interference from outside strong sunlight is inevitable. In order to eliminate the interference effect of sunlight effectively, a laser lock-in imaging technology was utilized. An external controlling circuit triggered the lasers and CCD image acquisition synchronously, and high quality image was achieved by means of laser lock-in imaging method. Lots of experiments verified that laser lock-in imaging makes the output of the rail wear more stable and adapt to a wide range interference of outside complicated background light. Experimental results show that laser lock-in imaging can guarantee stability of the measurement system, fundamentally eliminating the random measurement errors.