Calibrator automatic calibration system for headlamp tester of motor vehicle based on image processing

In order to make sure the measurement accuracy of calibrator for the headlamp tester, the optic axial angle and the light intensity of the calibrator should be detected periodically. In consideration that the degree of automation in the traditional testing scheme is insufficient and the repeatability of test is difficult to guarantee, a testing method is proposed. This method is based on the combination of image processing and the high-precision electric turntable. The automatic detection of calibrator with a high precision is realized by using the equal ratio relationship between practical displacement and pixel displacement, as well as the linear relationship between image plane's illuminance and object plane's illuminance. The experimental data obtained under different illuminances is fitted by the use of least squares. And the regression linear equation can be got, and the equiluminous curve of vertified calibrator is drawn. The experimental analysis shows that the measurement accuracy of optic angle can reach 40″ and the relative measurement uncertainty of illuminance is less than 1% at the distance of 10 m. ©, 2015, China Ordnance Society. All right reserved.