Line Laser Rotary Scanning 3D Reconstruction System And Its Application In Underwater Environment

The ocean contains rich resources.At present,most of the research on 3D measurement technology is aimed at targets in the air,but the reconstruction of targets in underwater environment is still developing.In order to complete the detection and reconstruction of targets in the air and underwater,an active rotating scanning 3D reconstruction system is designed.The core idea is to use structured light source with industrial camera to obtain object surface depth information,and obtain object surface three-dimensional contour information through image processing,demodulation and coordinate transformation.Point laser scanning measurement technology has high precision and strong adaptability.It has become one of the most widely used three-dimensional measurement technologies,but its efficiency is low.Therefore,line laser projection scheme is adopted to improve the information acquisition rate.In order to realize the fast overall demodulation of a single image carrying a large amount of depth information,the matching relationship between the line laser plane and the image plane is established by using the spatial constraints of the acquisition module.Based on this theory,the system mathematical model is constructed to overcome the problem of multi-point coordinate matching calculation.In the calibration link,the corner of the chessboard calibration board is directly selected as the acquisition identification point,which avoids the step of extracting the light band center in the traditional way,increases the line laser plane fitting efficiency,and adds the bilinear interpolation method to correct the image.In the aspect of image processing,a lot of research is carried out from three aspects: image characteristics,noise suppression and extraction.The extraction method of morphological filter combined with adaptive direction template is designed,and the image processing flow and extraction accuracy are tested.The results show that the reliability of the extracted light band center is higher than95%.In the error analysis part,the system error model is established,and the influence of multiple parameters on the reconstruction accuracy is analyzed.Finally,the influence of refraction on the optical path of underwater imaging is analyzed as the theoretical basis of underwater reconstruction.In the reconstruction experiment,the system can restore the threedimensional appearance of water and underwater targets.In the field of view of 420 ～ 850 mm system,the ranging error is less than 0.27 mm and the size measurement error is less than0.32 mm.The experimental results show that the system performs well in accuracy,real-time performance and reconstruction effect.The work of this paper not only enriches the research in the field of three-dimensional measurement,but also has a certain reference value for the subsequent application research with the gradual development of marine resources.