Study On Accuracy Calibration Method Of LED Die Quality Equipment Based On Machine Vision

In the LED die production process, photoelectric parameters testing of the LED die is required before encapsulation, and the LED die is sorting, subsequent die packages requires high alignment accuracy after sorting of the die.In order to ensure the accuracy of the die is arranged, the accuracy of the LED test and sort machine must be calibrated.However, due to precision calibration of the LED all-in-one machine is more complex, the current calibration efficiency is very low. This paper analyzes Vision calibration method of the LED all-in-one machine, and designs a set of visual calibration device to calibrate camera visual equivalent and center of rotation and drive ratio, the main contents are as follows:First, this paper analyzes the precision calibration method of general machine equipment, and emphatically introduces the research status of machine vision camera calibration method. Then it analyzes the calibration sections that is required in LED all-in-one machine, and proposes technical solutions for the calibration of vision of equipment.Then, it establishes camera imaging geometric model Vision system and analyzes the effect of lens distortion of camera calibration.After introducing the calibration methods of visual equivalent, it designs a set of calibration device to compare the calibration effect through experiments before and after the use of calibration device.After analyzing the principle of Angle correction of Angle deviated die, it uses least squares to fit out the center of rotation coordinate on supply area. Through the experiments of Angle correction of Angle die, it verifies the precision of drive ratio by vision calibration is higher than that by the mechanical structure design.Finally, the paper uses the calibration device and the original calibration method respectively to calibrate continuously visual equivalent and center of rotation and drive ratio, and compares the calibration results.The experimental results show that the calibration accuracy is higher, and time-consuming is obviously much shorter when using the calibration device to calibrate the visual accuracy.