Research On The Development Method Of Image Color Quality Calibration Light Source

In order to meet the needs of improving the precision of color printing,photography,and intelligent instruments,a new image color quality calibration light source was designed.Using a kypton lamp to simulate the standard A light source,29 kinds of COB integrated packaged high-power LED were used as the basic light emitting unit to simulate the spectrum of standard B,C,and D65 light sources in the visible light range of 380 nm to 780 nm.A spectral matching algorithm based on genetic algorithm was designed to fit the target spectrum.Take the measured linear normalized spectral power distribution data for each LED spectral model,then,use this spectral matching algorithm to obtain the proportional coefficient of each LED light power.The differences between the theoretical fit spectrum and the standard B,C,and D65 light source spectra obtained by this algorithm are 5.93%,5.05%,and 4.87%,respectively.A multi-channel ?-conversion adjustable constant-current drive circuit was designed for a variety of LED drivers.The main performance parameters of the drive control circuit were analyzed.The test results show that the linearity of the VI-conversion adjustable constant-current drive circuit is 0.9999999,and the non-stability of the output current drive circuit is 0.016%within two hours.A ring-shaped copper-based PCB was designed for mounting LED,and a S-type heat sink was used to cool the LED light-emitting unit.Light source control software was written by C#language to control the LED luminous flux.A LED light emitting unit performance test system was set up to measure the light quality,and an integrating sphere was used to homogenize the LED light.The non-stability of the light source measured by this system is 0.056%at stable working state.Meanwhile,the linear relationship between the optical power and the drive current control parameters of each LED was tested.Based on the cold white LED light power,the parameters of each LED drive current control were obtained from the linear fitting equation of the LED's light power and the driving current control parameters,thus the actual fitting spectra of each light source were obtained.The differences between the fit source spectra obtained through this method and the CIE standard B,C,and D65 light source spectra are 9.1%,7.98%,and 8.05%,respectively.The color rendering indices of the fitted light sources are 95.5234,96.6841,and 99.2833,respectively.The color rendering index of the A light source obtained by the kypton lamp is 99.3330.This design method can meet the requirements of the indicators well.