Research on 3D Visual Space Distortion in a Rotational-Stereo Micro Measurement System

Measuring 3D shape of the silicon-mold of microfluidic chips is very inconvenient because its height is only about 80 mum. There are a few of researches focus on the 3D optical micro-visual-measuring systems at present. A novel rotational-stereo-based micro measurement system (RSMMS) is developed for 3D measurement of silicon-mold used for reproduction of polymer microfluidic chips. Related measuring technique based on rotational stereo is proposed. The rotational stereo transformation about arbitrary rotation axis in visual space is defined by quaternion representation, and then the working principle and the structure of the system are designed. The weak perspective vision model based on the imaging geometry of RSMMS is introduced. Based on the perspective projection relation of RSMMS, visual space distortion of a micro measurement system based on rotational stereo is researched. The variation of 3D iso-distortion surface depending on the distortion factor is analyzed. Simulation results described a general law of 3D visual space distortion in micro visual space and provided a theoretical evidence for the generation and rectification of actual distortion in visual space.