| Multispectral imaging,which is widely used in the biomedical field,is an effective tool for the non-invasive observation of biological tissues.However,multispectral imaging is affected by the irradiation quality of the light source,and inhomogeneous irradiation during multispectral data acquisition can cause unwanted effects such as glare,specular reflection,and shadows.Therefore,further researches on multi-band medical light source systems providing homogeneous irradiation is of great significance to the biomedical field.This study designs and optimizes two uniform light source systems for biomedical applications,one of which proposes a uniform light source system with a ring structure,a uniform light source system with an integrating sphere structure.Both systems aggregate multiple narrow-band LEDs as the system light source,which can provide uniform irradiance.In theory,the two systems are simulated and structural parameters optimized by Monte Carlo ray tracing,then the prototype systems are fabricated according to the optimal parameters for irradiance uniformity and broad-spectrum compatibility testing;after which further application experiments such as vein visualization testing and tooth surface image acquisition are conducted.The main works are as follows.(1)For the irradiance uniformity requirements of the light source application scenario,a ring structure uniform light source system is designed,then the parameters such as the angle and the distance that between the LED light source and the test plane are optimized by Monte Carlo ray tracing.(2)For application scenarios with multi-functional requirements,a homogeneous light source system with an integrating sphere structure that is compatible with endoscopic use is designed.Theoretically,the positioning of the integrating sphere cavity light source and output slot are discussed based on Monte Carlo ray tracing,and structural parameters such as cavity size,the layout of LED light source,and output slot size are optimized.(3)The constant current driving circuit of the LED light source is designed based on the operational amplifier,and the control of the constant current driving circuit of LED light source by the virtual instrument is realized through the Lab VIEW program driver.(4)The prototype systems of ring structured uniform light source and integrating sphere structured uniform light source are built,followed by the tests of irradiance uniformity and broad-spectrum compatibility.In terms of experimental applications,wound images,vein visualization images,and tooth surface images are performed after irradiation at different wavelengths,which results show that both systems have high irradiance uniformity and have potential applications in the biomedical field. |
