Illumination and projection optics for spatial frequency domain fluorescence imaging

摘要

A digital micromirror device (DMD) based structural illumination and projection optical system were designed and evaluated for fluorescence imaging and diffuse reflectance imaging of tissue in spatial frequency domain, respectively. Light emitting diodes (LEDs) at discrete wavelengths (532, 620, 656 nm) provided illumination for the diffuse reflectance imaging while a 532 nm laser diode (LD) was used as excitation light source of photosensitizer (PS) fluorescence. Both the LEDs and LD light were collimated, homogenized and converged on a DMD to generate the structural illumination. A projection lens was also designed to project a rectangular structural illumination spot on target tissue. The designed optical system could be applied to provide variable frequency structural illumination for depth sensitive excitation of PS and diffuse reflectance imaging.