激光扫描实现亚像素级3D表面测量技术

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"本文主要探讨了利用激光扫描技术进行亚像素级别的三维表面测量方法。该方法结合了视觉相机和结构光技术,旨在提高三维重建的精度。文章详细介绍了亚像素校准、激光条纹检测以及三维重构的算法,并对不同亚像素校准策略进行了比较,实现了约0.2像素的三维坐标精度。此外,为了满足工业应用中的精度和处理速度要求,文中还选择了相应的重构算法。关键词包括:视觉、激光、尺寸测量、校准。" 在工业生产过程中,精确的三维测量对于产品质量控制至关重要,尤其是在产品的最终检查阶段。传统的测量方法可能无法达到亚像素级别的精度,这限制了其在精密制造领域的应用。为此,本文提出的亚像素测量技术通过激光扫描和视觉相机的结合,显著提升了测量的准确度。 亚像素测量是通过对图像中边界位置的精确估计来超越像素格栅限制的一种方法。在本研究中,作者实现了一套包括亚像素校准、激光条纹检测和三维重构的完整流程。亚像素校准是整个系统的关键部分,它涉及到对相机和激光器的精确标定,以确保测量结果的准确性。文中比较了几种不同的亚像素校准策略,通过实验验证,这些策略可以将三维坐标测量的精度提升至约0.2像素,极大地提高了测量的分辨率。 激光条纹检测是测量三维表面的关键步骤,它通过分析由激光照射物体表面产生的条纹图案来获取表面的信息。这一过程需要高速和精确的图像处理技术,以便在图像中准确识别和定位条纹,从而计算出物体的深度信息。 三维重构算法的选择对于满足工业应用的实时性和精度要求至关重要。这些算法通常基于三角测量原理,结合亚像素级别的条纹检测结果,计算出物体表面的三维坐标。论文中选取的算法能够在保持高精度的同时,保证了处理速度,适应了生产线上的快速测量需求。 本文的研究成果为工业环境中的三维表面测量提供了一个高效且精确的方法,对提高产品质量控制和智能制造有着积极的推动作用。通过不断地优化和改进,这种亚像素测量技术有望在未来得到更广泛的应用。

翻译This SiO2 shell is a key component in the mechanism for reversible actuation, as illustrated by finite element analysis (FEA) in Fig. 1C. An increase in temperature transforms the SMA (nitinol) from the martensitic to the austenitic phase, causing the 3D structure to flatten into a 2D shape. The responses of the SMA elements at the joints act as driving forces to deform the PI skeleton. This process also elastically deforms the SiO2 shell, resulting in a counter force that limits the magnitude of the deformation. The change in shape ceases when the forces from the shell balance those from the joints (right frame in Fig. 1C). Upon a reduction in temperature, the SMA changes from the austenitic back to the martensitic phase, thereby reducing the force produced by the SMA at the joints to zero. The elastic forces associated with the shell then push the entire system back to the original 3D geometry (left frame in Fig. 1C). Figure S3A simulates the moments generated by the SMA and the SiO2 shell. In the FEA model, the SiO2 shell appears on both the outer and inner surfaces of the 3D robot, consistent with experiments (fig. S3B). Although a single layer of the SiO2 shell at the outer or inner surface can also provide restoring force, the double-layer shell structure follows naturally from the conformal deposition process. This actuation scheme allows for reversible shape transformations using a one-way shape memory material. Without the shell, the structure only supports a single change in shape, from 3D to 2D, as illustrated in fig. S3C. Figure 1D shows optical images of a freestanding 3D peekytoe crab on the edge of a coin, highlighting the preserved 3D geometry enabled by the SiO2 shell after release from the elastomer substrate. Other 3D structures in geometries that resemble baskets, circular helices, and double-floor helices also exhibit high shape storage ratios (>85%) after cycles of heating and cooling (fig. S4). This ratio (s) is defined as s = 1 − |L1 − L0|/L0 × 100%, where L0 and L1 are the distances between the bonding sites at both ends at the initial stage and subsequent stages, respectively

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