Design And Implementation Of A Highly Stable Integrating Spherical Light Source System

With the development of information technology,Digital cameras can not only obtain spatial information and surface texture of objects,but also quantitatively measure light information radiated by objects,such as aerospace remote sensing.In many specific occasions,the digital camera must be calibrated for radiation,which puts forward new requirements for the imaging system’s radiation calibration technology.Integrating sphere light source is one of the key equipment for imaging system radiation calibration,and can produce a surface light source with high uniformity.Based on the actual needs,this article has developed a set of integrating sphere light sources for digital camera radiation calibration,which has very good practical value.In this paper,based on the retrieval of a large number of relevant domestic and foreign literature and market research,according to the actual application needs,the overall scheme of high stability integrating sphere light source system is formulated.The system is mainly composed of large-diameter integrating sphere,high-performance LED light source and drive circuit,high-precision light and brightness acquisition circuit and control module.The paper introduces the system design and implementation process in detail.Firstly,the principle of the integrating sphere and the characteristic parameters of the light source are analyzed,and the structure and parameters of the integrating sphere are determined according to the technical requirements of the system.According to the principle and characteristics of LED,the driving circuit of LED lamp is designed.The entire control system is centered on high-performance ARM.The forward channel uses photodiodes and high-precision analog-to-digital converters to achieve digital measurement of brightness.The backward channel uses high-precision digital-to-analog converters and power circuits to implement high-power LEDs.Precise control of the light source.The circuit schematic diagram of the control system is designed,the PCB board is produced,the firmware program of each module is written,the processing and debugging of each part are completed,and the development of the prototype is realized.Finally,the experimental measurement of the technical parameters of the developed prototype showed that the technical indicators of the high-stability integrating sphere light source system developed in this project had reached the design requirements and had good practicability.