Study On Automatic Following Optical-Axis Tester For Automobile Headlamps

The technology of automatic following optical-axis tester for automobile headlamp is a complex technology based on many subjects. It is a special instrument integrated with technology of optics, mechanics and electronics. It has the functions of automatic following optical-axis, using the CMOS image sensor to get the headlamp images, and using the technology of digital image process to get parameters of headlamp. Image processing technology is a comprehensive subject connected with the computer technology, automatic technology, electron technology and so on. It is the important field in the development of the computer. This paper attempts to use the advanced embedded system, deeply research how to automatic follow the optical-axis rapidly and accurately, how to get the headlamp image, how to measure the high and low light of automobile headlight, and how to enhance the accuracy and anti-jamming from the view of project application. This paper consists of eight parts: 1) This chapter analyzes situation and development of automobile tester technology at home and abroad. The measure standard and measure principle, basic element and the kinds of the automatic following optical-axis automobile headlight tester is pointed out;the content of this paper and key technology are described briefly. 2) The component of automotive following optical-axis automobile headlight tester is introduced. The paper also analyzes the characteristics, working principle and system structure of the production and expounds the theories of measurement 3) This chapter introduces the whole design scheme and structure of the automatic following optical-axis tester for automobile headlamp. 4) In this chapter, the component and the analysis of the hardware system of the tester are introduced. The advanced embedded system as the core of the system, it is responsible the control of the system and getting the image of headlamp, and control the electromotor in horizontal and vertical directions to auto-align the optical axis. 5) In this chapter, the control system is introduced, the core is using the fuzzy control system to enhance the speed and precision of auto-following the optical-axis, and enhance the efficiency of the tester. 6) Processing of the images which getting from the CMOS image sensor to get parameters of the vehicle headlamps which the standards needed. The Fresnel lens in the optical receptor spotlights the headlamp beams to form their image at the 1-meter distance between the optical receptor and headlamps. CMOS camera as an image sensor, takes the photos of their images, which are captured by VG-M201, The application of some digital image processing techniques to these images, such as edge-picking up, least-square fitting-curve algorithm, is to calculate the offset position/angle of optical axis of the high beams and the nodical offset of the unsymmetrical facular light and shade cut-off line of the low beams. This part and the fifth chapter are the emphases of the paper. 7) By making experiment and analyzing the result, we draw some conclusion.8) Finally, the main research contents of full text are summarized, main research conclusions and innovation points are given, and the insufficiency of this paper and research emphases in the future are pointed out.