Structured Light 3D Measurement Technology For Reflective Properties Of Metallic Surfaces

As the most widely used material in the industrial field,metal detection and measurement has always been the focus and difficulty of research.Among them,structural light measurement technology is regarded as the future three-dimensional measurement with its simple,high-speed and accurate characteristics.During the visual measurement process,the high reflection characteristics of the metal surface cause the external light intensity to exceed the dynamic range of the camera,resulting in overexposure,which makes the measurement difficult.In this paper,the mathematical model,calibration process and phase unwrapping of monocular structured light measurement system are introduced in detail.The reflective characteristics of metal surface are analyzed,and the algorithm for 3D measurement of metal reflective surface is deeply studied.The main research contents are as follows:(1)The measurement principle,system model establishment and calibration process of the monocular structured light measurement system are studied.The camera imaging principle and the coordinate transformation relationship and phase extraction technology are analyzed in detail.(2)The reflective characteristics of metal surface were studied.The reason why the metal surface was prone to reflection was analyzed by combining the camera sensitization model and imaging principle and the surface reflection model of the object.(3)A topography measurement algorithm for camera automatic multi-exposure is proposed.The camera response curve reflects the mapping relationship between pixel gray value and camera exposure.The algorithm obtains the range of scene illumination value based on the calculated camera response curve.The division of the degree values results in multiple exposure times.(4)The three-dimensional measurement algorithm for metal reflective surface is studied.A multi-view and multi-exposure measurement system is proposed for the characteristics of complex structure,large curvature change and high light reflectivity.A fast single-shot automatic exposure algorithm is proposed for the small metal surface.In order to improve the measurement efficiency,a new automatic exposure measurement algorithm for multi-scene measurement is proposed.(5)Set up the measurement system and apply the algorithm proposed in this paper to measure the metal surface.