为了解决采集图像时相机与旋转铣刀刀刃位置不确定的问题及提高图像处理的时效性,提出了一种基于机器视觉的铣刀磨损在机检测方法。根据结构相似性算法判断刀具图像质量,并引入图像采集间隔角度系数,确定了图像采集间隔角度与主轴转速。采用加速段特征测试(Features from accelerated segment test,FAST)算法实现了对刀具磨损区域快速、准确地自适应裁剪。基于FAST 特征点提出了自适应阈值分割方法,有效提取出磨损区域边缘。采用Hough 变换和最小外接矩形法,实现了对主切削刃倾斜角度的校正,进而提取出磨损区域B 区的平均宽度。最后开展了铣削试验,在16 组试验中,计算值与真实值的最大、最小和平均误差分别为4.76%、0.91%、3.63%。试验结果表明,该方法可在主轴旋转时获取所有铣刀磨损区域的高质量图像,进而高效、准确地提取磨损参数。
Abstract
To solve the problem of uncertain position of camera and rotary milling cutter blade and improve the timeliness of image processing
a milling cutter wear detection method based on machine vision is proposed. According to the structure similarity index
the image quality of the tool was judged
and the image acquisition interval angle coefficient was introduced
and the image acquisition interval angle and spindle speed were determined. Features from accelerated segment test (FAST) algorithm was used to achieve fast and accurate adaptive cutting of tool wear area. Based on FAST feature points
an adaptive threshold segmentation method was proposed to effectively extract the edge of the wear region. Hough transform and minimum external rectangle method were used to correct the inclination angle of the main cutting edge
and then the average width of the wear zone B was extracted. Finally
the milling test was carried out. In 16 groups of tests
the maximum
minimum and average errors between the calculated value and the real value were 4.76%
0.91% and 3.63% respectively. The experimental results show that the proposed method can obtain high-quality images of all milling cutter wear regions when the spindle is rotating
and then extract wear parameters efficiently and accurately.