存在概率的工业CT图像快速圆测量

针对逆向工程中一般测量方法无法实现对封闭工件内腔进行测量,以及采用铣削层切法等传统测量法测量工件内腔具有破坏性等缺点,通过计算机层析成像测量法实现对工件的精确测量.对获得的工件CT图像,利用图像测量法测得工件内腔尺寸,并在CAD软件中进行编辑、完善并标注尺寸.首先利用基于存在概率的方法确定图像中圆的位置,并获得其像素尺寸,然后根据图像大小与视场直径得到像素的实际大小,二者的乘积即为圆的实际大小.对一具体工件进行测量,试验结果表明利用此方法测得的圆半径与实际尺寸的相对误差小于0.5%,测量时间在几秒之内.

Fast circle measurement of industrial CT images based on existence probability

The general methods in reverse engineering cannot measure the inside of close parts.Traditional methods like Capture Geometrical Inside(CGI) would destroy the part.We used the industrial computer tomography(ICT) method to obtain accurate measurements of close parts.Based on the acquired computer tomography images,the size of an internal part was obtained through image measurement and subsequently edited,amended,and dimensioned in CAD software.First,the position and the pixel size of the circle were determined based on existence probability.Next,the actual size of one pixel was obtained based on the image size and the purview diameter.Finally,the actual circle size was calculated by multiplying the pixel size and the actual size of one pixel.A real part was measured using the method.The results show that the relative error of the measured circle radius and the actual size is less than 0.5% and the measuring time is several seconds.