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New 3D high-accuracy optical coordinates measuring technique based on an infrared target and binocular stereo vision

Three-dimension coordinates measuring is the key technique in modern manufacturing, reverse engineering, automation, precision measurement and computer aided surgery. In recent years, the 3D vision coordinates measurement becomes a newly technique and has been developed rapidly. Some vision coordinates measurement machines (VCMM) were developed. But measuring accuracy of those VCMMs is susceptible to the mal-condition and external noise, i.e. index point brilliance and ambient light illumination. We developed a new 3D high-precise optical coordinate measuring system based on an infrared target and two CCD cameras. Both measuring principle and linear direct reconstruction method of binocular stereo vision based on cross optical axes are discussed. The detail design and geometric model of the infrared target is proposed. The position and direction of the infrared target and 3D coordinates of the tip can be directly computed according to rigid geometric transformation. Further results of calibration and measurement are verified experimentally. A high geometrical accuracy can be reached.