Spectrally tunable light source based on a digital micromirror device for retinal image contrast enhancement

  • P. Bartczak
  • D. Čerāne
  • P. Fält
  • P. Ylitepsa
  • E. Hietanen
  • N. Penttinen
  • L. Laaksonen
  • L. Lensu
  • M. Hauta-Kasari
  • H. Uusitalo
Keywords: biomedical optical imaging, diabetes, lighting control, tunable light source, micromirrors


Different optical methods for retinal imaging provide a significant improvement for image analysis and help with data interpretation. The use of tunable light sources, which have been optimized for contrast enhancement of various retinal features or lesions in retinal images, could simplify the eye fundus examination through enhanced image quality. In this study, we have developed and described a research prototype which consists of a spectrally tunable light source based on a digital micromirror device which is further coupled to a fundus camera. The overall aim of this construction was to generate illuminations optimized for enhanced retinal image feature visibility. The optimized illumination conditions were compared to traditional red-free imaging and the measurements were executed for an artificial eye followed by in vivo measurements of the eyes of three volunteers. In all cases, the retinal image contrast was observed to improve compared to the traditional red-free imaging. Depending on the observed retinal feature, the perceptual improvements in the contrast varied from a few percent to nearly 70 percent.
Nonlinear and Coherent Optics