Spatio-angular filter (SAF) imaging device for deep interrogation of scattering media

Citation

Pandya, Aditya, Irina Schelkanova, and Alexandre Douplik. “Spatio-angular filter (SAF) imaging device for deep interrogation of scattering media.” Biomedical Optics Express, vol. 10, no. 9, 2019, pp. 4656–63.

Keywords

• Spatio-angular filter (SAF) imaging
• Scattering media
• Deep tissue imaging
• Numerical aperture (NA) gating
• Fiber optic plate (FOP)
• CMOS imaging
• Intralipid
• Resolution target
• Interrogation depth
• Contrast ratio

Brief

A novel spatio-angular filter (SAF) imaging device using a low numerical aperture, coherent fiber optic bundle coupled to a CMOS imaging platform allows deeper imaging in scattering media, such as human tissue.

Summary

The authors created a new imaging device called a spatio-angular filter (SAF) imaging device to improve the depth at which an object can be imaged through a scattering medium. The SAF device utilizes a low numerical aperture (NA) fiber optic plate (FOP) coupled to a CMOS imaging platform to gate the numerical aperture, or acceptance angle, of light The article compared the interrogation depths of three imaging setups: two setups used a FOP with varying NAs (0.17 and 0.55) and one setup used a 0.25 NA lens. Using a 1951 USAF target submerged in varying concentrations of Intralipid (1-4%) to mimic scattering in human tissue, they found that the interrogation depth of the lower NA FOP (0.17) was approximately 2 times greater than the higher NA setups. The increased interrogation depth of the lower NA FOP is due to its ability to better reject scattered photons, which improves the contrast and visibility of the target at greater depths.