Research Of Measuring System For Calibrators Of Headlamp Tester For Motor Vehicle

The lighting and light matching capability of the automobile headlamp is very important to the safety of night-driving .The measurement of automobile headlamp must use the headlamp measure instrument, which is needed to use a calibration instrument to calibrate. However, whether the calibration instrument is standard must be checked up by a measure system.With the development of Opto-Electronic Technology , semiconductor Technology , Computer Technology and image processing Technology, the photoelectric non-contact measuring technology was used more widely in the field of measurement, which has changed the shortcoming of the contact measuring method in precision and speed and improved realtime and automation of measurement. A measuring system for calibrators of headlamp tester for motor vehicle using planar array CCD as detector is introduced in the paper. It utilizes the computer digital image processing technology. And this system can measure the characteristic parameters automatically and quickly, such as luminous intensity, center of far light, corner of the close light. The advantage is high accuracy, good repetition and automatic measurement. It is proved in application that this system tallies with national standard of lamp performance measuring. Its virtue is the high precision, good repetition, making measurement automatized.In this paper, Chapter One introduced general situation and nation standard in the measurement of light, and the technological requirement of the system. Wecompared some measuring methods in our country and in the foreign country. So we offered the method of using array CCD as detector.In Chapter Two, through the analyzing for principle, characteristic and practical demand of the measurement, the structure design is been accomplished. In the first part, the blue print of the whole structure of the measuring instrument and main parts is brought forward. In the second part, the detailed design is brought forward. CCD imaging theory is expatiated, the concrete optical route is designed and analysis on choosing the main accessory is given. In the drive device system, detailed design on metrical element is processed and analysis on choosing the other accessories is given. For example, how we choose the CCD, and the grating. And how we design the structure of the mechaine. In the last part, the whole course of the measurement is advanced.Chapter Three introduced some knowledge of digital image processing, including palette, grayscale and DIB, but mainly talk about the structure of the BMP file. Also we mainly introduced image transform method that we often use. For example the filtering, binarization.In Chapter Four, the blue print of the whole structure of the software system and main parts is brought forward. The image processing software system can not only fit the purpose of image processing but also gives a stage for farther exploitation on image processing. In the third part, the method of software realization on measure-controlling is given out, so we can automatically control the measurement course, data collecting and data processing automatically, the transforming of the TIFF format, the produce of the equal illuminance curve. And in these, I gave the source program of the key part.At last, I chiefly introduced about the experiment that has been done, and analyzed the data, then brought out the elementary conclusion. At the same time, the conclusion that the instrument can fit the demand is gained, trough academic error analysis and calculation on resolution and measuring range.In conclusion, the photoelectric system for measuring the position of the hole on the surface of the sphere is a high speed and precision system, which is aorganic system of image data acquisition image processing image show. The principle of this photoelectric measuring system enrichs the measuring theory in the fileld of non-contact measurement and supply references to the measuring of the headlamp.