An Accurate Image Measurement Method Based on a Laser-Based Virtual Scale

Sensors

Yonghui Huang¹  Shiping Huang²  Wei Ding² 

[1] Guangzhou University – Tamkang University Joint Research Center for Engineering Structure Disaster Prevention and Control, Guangzhou University, Guangzhou 510006, China;School of Civil Engineering and Transportation, South China University of Technology, Guangzhou 510640, China;

关键词: non-contacting measurement;    full-field scale;    laser virtual scale;    moving least squares;   

DOI  :  10.3390/s19183955

来源: DOAJ

【 摘 要 】

Image measurement methods have been widely used in broad areas due to their accuracy and efficiency. However, current techniques usually involve complex calibration, an elaborate optical design, or sensitivity to the test environment. In this paper, a simple optical device was designed to emit parallel beams to obtain a virtual scale for measurement purposes. The proposed theory ensures the robustness of the system when obtaining each scale in the presence of uncertainty. The scale creates a mapping from image coordinates to world coordinates. By using the moving least squares (MLS) method, a full-field scale map can be reconstructed to achieve high-precision measurement at the sub-pixel level. Experimental verifications are carried out, showing that the proposed method provides very accurate and reliable results. The proposed approach is simple in terms of equipment, and the scale can be automatically calculated. Therefore, the system proposed in this paper is a promising candidate as a tool for non-contacting measurements (e.g., the crack development, geometric size) in the inaccessible structures such as high-rise buildings and long-span bridges.

【 授权许可】

Unknown