A Study For Key Techniques Of 3D-Sensor Based On Line-structure Light

The optic 3D-measurement have been widely researched and extensively applied for its advantages, such as non-contact, fast/high speed measuring, and high precision and flexible control by computer. As one of the active 3D-measurement technologies, the laser triangulation method, which is based on line structure light scanning, has been widely used in quality-control and Reverse-Engineering. It is to project a laser sheet onto the tested surface, and form a light line on the surface. The camera will capture the distorted stripe, which is deformed by the shape of the tested surface. The height of one section of the object surface can be obtained after computing the pixel coordinates of the light line, and the whole 3D shape can be got with a one-dimension scanning rig. Some solutions about the key problems in the line-structured-light 3D measurement have been proposed.An easy real-time calibration method, which is based on 2D calibration object, has been presented. It doesn't need a complicated and elaborate 3D calibration model but to place a 2D calibration plane at several arbitrary places in the common range of two sensors. So the relationships between the line-structure-light plane and the two sensors will be established after merging the calibration data of each local world coordinate into a global world coordinate. So it reduces the requirement of a high accuracy calibration object and the complicate calibration procedure. A method to calculate the rotation axis of the rotation table has been proposed, which is to obtain the equation of the rotation axis by 3 sorts of method after placing the 2D calibration plane on the rotation table and capturing some images at different rotation places.An approach, i.e. surface light scanning, which is to reduce the effect of the speckle noise in three-dimensional surface laser light sensing has been presented. It produces a spatially-varied dynamic light field of speckle by moving the scanning surface light, which is projected onto the surface of the tested object. Therefore, the speckle noise effect can be reduced by the time average and the measuring precision will be dramatically improved.A new effective data-fusion method is presented, which can eliminate the errors...