利用三频外差方法获取小型工业零件三维面型信息

Obtaining Three-dimensional Surface Information of Small Industrial Parts by the Method Based on Three Frequency Heterodyne

随着以智能制造为主导的工业4.0时代到来,“机器视觉”可取代人工帮助企业有效提高生产效率和降低生产成本,在智能制造中占据核心地位。为了更好地培养新时代智能制造人才,在教学过程中需有机结合“机器视觉”理论知识与其现实中的实用价值。本文采用基于三频外差原理的光学三维测量方法实现了对某小型工业零件三维面型信息获取。将三种不同频率的条纹图案依次投影到被测物体表面,利用相移和三频外差相位展开算法可以从相机采集到的经被测物高度调制后的变形条纹图中得到包含被测物体面型信息的展开相位,对测量系统进行标定,得到相位与真实高度间的映射关系,在此基础上进一步获取被测物的真实三维面型信息。此外,通过投影白色图片到被测物并对相机采集到的图片进行阈值分割的方式对重建出的被测物三维面型中的阴影区域实现了定位,从而去除了重建结果中的无用阴影区域面型信息。

With the arrival of the Industry 4.0 era dominated by intelligent manufacturing,machine vision can replace manual labor to help enterprises effectively improve production efficiency and reduce production costs,occupies a core position in intelligent manufacturing.In order to better cultivate intelligent manufacturing talents in the new era,in the teaching process,it is necessary to organically combine the theoretical knowledge of machine vision with its practical value in reality.The paper obtains three-dimensional(3D)surface information of small industrial parts by the optical 3D measurement method based on phase-shifting and three frequency heterodyne phase unwrapping method.Three different frequency stripe patterns are sequentially projected onto the surface of the measured object,the phase-shifting and three frequency heterodyne phase unwrapping algorithms can be used to reconstruct unwrapped phase of the measured object from the deformed stripes modulated by the measured object surface collected by the camera.By calibrating the measurement system to obtain the mapping relationship between phase and height,the 3D surface information of the measured object can be obtained.In addition,by projecting white images onto the measured object and performing threshold segmentation on the images captured by the camera,the shadow areas in the reconstructed 3D surface of the measured object were located,thus removed useless shadow area surface information from the reconstruction results.