CCD Photoelectric Measurements in Calibrators for Vehicle Headlamp Tester

摘要

Vehicle headlamp is a very important component for safe driving. The calibration of vehicle headlamp must be done in accordance with standard (JJG967-2001), such as the distribution of shade and the luminosity distribution of far light and close light. Photoelectric measurements, for example, electronic scanning system, dot array of photoelectric cell system and CCD measurement system, were used to research the shade distribution and the luminosity distribution. In order to expedite the measuring process and acquire more accurate parameters, CCD measurement system is proposed to measure more characteristic parameters of headlamp at higher speed. Image processing technology is utilized to get the characteristic parameters such as luminous intensity and optic axis deviation angle for headlamp. Some software algorithms of digital image processing can be used to achieve an uncertainty of luminous intensity of less than or equal to 2%, and an uncertainty of deviation angle of optic axis of less than or equal to 1.6 minute. Experimental results showed that it has many advantages such as high precision, good repetition.