Flight Object Attitude Angle Measuring Fringe Projection System Design

Optical method of active non-contact surface profile measurement technology is without prejudice to the measured object, fast, for a wide range of advantages. For its important applications in industrial production and detection, it has become the current hot research point. This method can be used in objects'flight attitude angle measurement system, too. Fringe projector, as one of the key system equipments, the design of its parts has drawn more and more attention.This article described in detail the design principle of the various parts of fringe projector and the total design process, and showed corresponding design results by optical design software Zemax. Then we analysed some problems combined with the specific experiment and discussed and clarified the solutions. In design part, the semiconductor laser shaping and collimation method for laser lighting program was given, results optimized by computer simulation were obtained. For laser speckle problem, fiber and high-speed rotating ground glass were used to solve it effectively. For the problem of poor illumination uniformity on the captured images, relations between the projection lens focal length and tilt angle of the image surface and its influence on the plane uniformity of illumination have all been discussed with computer simulation. In filament lighting part, designs of compound eye lens and optical tunnel system were given by using non-imaging theory, and simulation results showed that it meets the requirement well. In the projection lens design section, we chose an initial structure from the available patents, optimized it by using the software, at last 4-piece and 5-piece style telecentric lens for laser (532nm) illumination and 7-piece type telecentric lens for white light illumination have been found.In the experimental part of this article, theoretical analysis of the 45°angle tilt projection has been made, a formula has been deduced to calculate the depth of field along the projection axis range and the MTF (Modulation Transfer Function). Then we took several stripes image along the projection axis, processed the sampling image by software, estimated image contrast and fitted it by the least squares method. The curve has been compared with the theoretical one, and its characteristics has been analysed. Difference between the theoretical models and the experimental results and its reason have been discussed.