Design of an optical probe for testing surface roughness and micro-displacement

This paper presents a practical monitoring tool for measurements of surface roughness and micro-displacement. An optical probe of the methods based on light scattering for measuring surface roughness and optical triangulation for measuring micro-displacement is described. The proposed technique allows evaluation of surface roughness and micro-displacement of specimen by using just one device. The theoretical models of surface roughness and micro-displacement measurements have been established for the probe. The measuring principles applied in the design are described in detail and the validity of the design is demonstrated by experimental evaluations. The experimental results show that, for specimens with surface roughnesses R_a in the range from 0.005μm to 0.1 μm, micro-displacement measurements in the linear range of ± 300μm can be obtained.     

光学薄膜表面微细缺陷在线检测方法研究

为了对光学薄膜进行精密光学检测,需要采用数个具有高解析度的线阵CCD相机进行光学薄膜缺陷图像的同步采集。基于计算机视觉的理论,提出了一种有效的自动质量监测方案,实现对光学薄膜表面微细缺陷项目的检测,并根据检测结果驱动打标机对光学薄膜缺陷进行自动标识和定位,该方法具有高精度、实时、在线和非接触的显著优势。探索性实验结果表明,采用该方法可获得光学薄膜表面缺陷的清晰图像,缺陷的细节能够得到很好的展现,并且能够完成缺陷特征的提取与识别。     

Subpixel edge location method proposed to improve the performance of optical fiber spherical coupling probe during dimensional measurement of micro-cavities with high aspect ratio

A subpixel edge location method based on orthogonal Jacobi–Fourier moments is proposed in this paper to improve the performance of optical fiber spherical coupling probe during dimensional measurement of micro-cavities with high aspect ratio. The effectiveness of the proposed method is proved through the performance test of a micro-hole measuring machine with optical spherical coupling probe. Test results indicate that a blind micro-hole of 400 μm in diameter can be experimentally measured at the depth of 2000 μm with a repeatability of 40 nm and an extremity resolution of 42 nm.     

基于投影法检测光学元件面形的图形处理算法

基于线结构光扫描测量和立体视觉测量相结合的三维检测方法——投影法,能够快速准确地实现光学元件面形的在线检测,通过对采集图片的图像预处理,区域立体匹配分析,曲线拟合及面形实验等算法还原被测光学元件面形模型。实验结果表明,将这种方法用于检测光学元件可以真实还原光学元件三维外貌特性,具有实际应用价值。     

Development of an optical inspection platform for surface defect detection in touch panel glass

An optical inspection platform combining parallel image processing with high resolution opto-mechanical module was developed for defect inspection of touch panel glass. Dark field images were acquired using a 12288-pixel line CCD camera with 3.5 µm per pixel resolution and 12 kHz line rate. Key features of the glass surface were analyzed by parallel image processing on combined CPU and GPU platforms. Defect inspection of touch panel glass, which provided 386 megapixel image data per sample, was completed in roughly 5 seconds. High detection rate of surface scratches on the touch panel glass was realized with minimum defects size of about 10 µm after inspection. The implementation of a custom illumination source significantly improved the scattering efficiency on the surface, therefore enhancing the contrast in the acquired images and overall performance of the inspection system.     

On the tribological behavior of retrieved hip femoral heads affected by metallic debris. A comparative investigation by stylus and optical profilometer for a new roughness measurement protocol

In this study, 35 retrieved ceramics femoral heads with evidence of metallic dark lines on the surface were analyzed. The surface roughness of these femoral heads was acquired using both a stylus contact profiler and an optical non-contact profilometer. The metallic deposition on hip ball surface, also known as Metal Transfer (MT), appeared as dark metallic and can occur during the surgery or during the reduction of a dislocated prosthesis. In this study, we validate a new protocol to measure surface roughness on retrieved femoral heads, by using the aforementioned two different acquisition techniques and also to investigate the hypothesis that such metal transfer retrieved ceramic femoral head is associated with increased surface roughness.All femoral components of this investigation showed remarkable differences in roughness values between MT-affected and MT-unaffected areas. The two acquisition procedures – conventional stylus and 3D confocal profilometer – confirmed a satisfying agreement, even considering the obvious resolution difference.