提出一种基于条纹反射的光学表面疵病检测方法, 检测系统由液晶显示屏、CCD相机和计算机组成.检测时在显示屏上分别显示水平和垂直两个方向正交的正弦性条纹, 用CCD相机记录经被测表面反射的正弦条纹像, 通过相移技术得到两个方向正交的相位分布和对比度分布, 通过对比度分布确定被测表面的疵病位置.被测面表面面形相关信息包含在相位分布中, 其表面疵病细节信息包含在局部微观相位分布之中.对相位分布进行多项式拟合后相减得到疵病引起的微观相位分布, 计算得到表面疵病的梯度分布, 积分得其高度分布.实验验证了该方法的可行性.

A method for the optical surface flaws inspection based on the fringe reflection was proposed. The test system is composed of the liquid crystal display, CCD camera and a computer. The intensity-modulated patterns are generated on the screens on both the horizontal and vertical respectively. The CCD records the pattern images via the tested surface. The phase and amplitude modulation are calculated by the phase-shift technique. The flaws location can be got from the fringe contrast. Also the height of the flaws can be gained by integration from the phase change caused by the flaws. This method is simple and cheap. Compared with other techniques, this technique can get the three dimension information of the flaws. The experimental results have confirmed the feasibility of this method.