钛合金叶片三维测量中背景去除的两步法研究

Study on the two-step method to remove the background in 3D measurement of titanium blade

摘要:

基于双频栅线法的三维测量系统因其相位的过程不 易受到噪声干扰而被广泛应用于三维轮廓测量领域。针对当测量对象为 钛合金叶片时,因叶片主体颜色和参考平面颜色对比度太低而引起的叶片连续相位图与背景 图像难以区分的问题, 提出两步去除背景法:首先将参考平面预置为黑色背景,以增大参考平面与钛合金叶片的颜 色对比度,实现有效区 分二者的目的；然后结合Matlab软件中的imcrop图像切割函数,进行有效包裹叶片的变形 光栅条纹图像的自动截取,进而运用双频栅线法进行相位展开,最终得到完整的叶片连续相 位图。实验结果证明,所述方法不仅可以有效地区分开叶片连续相位图与背景图像,从而将 背景图像完整去除,同时也提高了整个三维测量系统解相位的精度。

Abstract:

The 3D measurement system based on dual-frequency gratings is widely used because of its insensitivity to noise in the process of phase solution.However,it is difficult to distinguish the ob ject phase map and background image when the object to be measured is a titanium blade because of its low color contrast. So a two-step background removal method is proposed.Firstly,the reference plane is preset to be a black background in ord er to increase color contrast between the reference plane and the titanium blade,which will effectively distinguish them. Then the deformed raster images will be automatically captured with the imcrop function in the Matlab.Finally,the blade complete continuous phase map will be obtained.Experimental results show that the proposed method can not only effect ively distinguish the object phase map and background image,but also improve the accuracy of the solution phase.