环形光切测量法的亚像素技术

SUB-PIXEL TECHNIQUE IN RING LIGHT METHOD

针对深孔内膛的检测,对环形光切的测量方法进行了介绍,对其测量原理进行了分析。为了提高断面形廓的检测精度并消除CCD的量化误差、饱和误差、激光的不均匀误差和“散斑”噪声等误差和噪声对检测结果的影响,提出了一种亚像素检测技术,该技术在环形光斑图像中“刻画”出一系列截线,对这些截线灰度分布进行连续重建、基于小波变换的理想估计和理想灰度极值点计算,并利用这些极值点得到环形光斑的理想灰度极值线的亚像素检测结果,从而实现深孔断面形廓的测量。该方法具有检测精度高(可达到0.1像素的位置精度),抗噪能力强,没有数据的缺失和冗余现象,能够检测复杂的断面形廓等特点,对于具有一定复杂程度的深孔内膛形貌检测具有重要的意义。

Aiming at the deep hole detection, the method offing light section is introduced and its principle is analyzed. To enhance its detection precision and eliminate the influence of error and noise on its detection result, such as the error caused by CCD quantization and saturation, the unevenness and speckle of the laser light and so on, a sub-pixel detection technique is proposed. This technique layouts a series of transversal lines on the ring light spot image, reconstructs their continuous gray distributions, estimates their ideal gray distributions based on wavelet transform, and computes their ideal extreme gray points. By these extreme gray points, the ideal extreme gray line of ring light spot is detected in sub-pixels and then the profiles of deep hole are measured. With a property of high precision （0.1 pixels）, high power of noise proof, no data deficit and data redundancy, and a capability of complicated profile line detection, this technique is important for measuring complicated inner surface of deep hole.