基于机器视觉技术的研磨表面粗糙度检测

Measurement of Lapped Surface Roughness Based on Machine Vision Technique

为了对研磨表面粗糙度进行快速在线检测,基于机器视觉技术提出了一种研磨表面粗糙度检测方法,建立了研磨表面粗糙度评定参数体系。该方法利用CCD提取粗糙度Ra在0.012～0.1um之间的研磨表面图像,运用中值滤波、图像边缘增强和图像二值化等对图像进行预处理,然后通过图像特征参数提取研磨表面粗糙度信息,包括灰度均值D和均方根差Sq。试验结果表明,在入射角一定的情况下,入射光越强,D和Sq对粗糙度的变化越敏感;在入射光强一定的情况下,入射角越大,D和Sq反映粗糙度变化的效果越好;与Sq相比,D对于入射光强和入射角的变化更不敏感,具有更强的稳定性。利用图像参数评估研磨表面粗糙程度的最佳实验条件为:入射角70°、入射光强2.0×104lux以上。

Based on the machine vision technique, a method for fast and on - line measuring the three - dimensional parameters of lapped surface roughness is proposed. The lapped surface image with Raranging from 0.012 to 0. 1um is acquired by CCD and stored in the computer. Firstly, the midvalue filtering, the image edge strengthening and the image binary conversion are used to preprocess the image. Then the the roughness characteristics are acquised from image parameters, such as gray mean value D and root mean square deviation Sq. It is proved by the initial experi- ment that at a fixed incidence angle, the stronger the incident light, the better correlation effect D and Sq with Ra At a fixed intensity light, incident of the larger the incidence angle, the better correlation effect D and Sq with Ra. D and Sq are all suitable for evaluating lapped surface roughness. Compared with Sq. D is more insensible to the incidence an- gle and the intensity of incident. The optimized experiment conditions for evaluating lapped surface roughness by image parameters are the incidence angle 70 and the intensity of incident intensity larger than 2.0 10^4lux.