Spectrum

The scattering parameters of a medium and the imaging resolution have a complementary relationship with the wavelength of the incident light. If the wavelength of the light is increased, photons penetrate deeper into the scattering medium; however, the imaging resolution decreases due to the diffraction limit. Decreasing the wavelength of the light improves the imaging resolution at the cost of decreased depth-of-penetration. We propose to employ multiple wavelengths to get best of both the worlds where we can image deeper, and also at better resolutions. In the past, the team demonstrated subsurface vein imaging enhancement using multi-spectral light and structured light.

 
 
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Subsurface Vein Imaging Enhancement

Direct/global image separation is achieved through the use of high-frequency coded illumination patterns – in this context, a high-frequency checkerboard. After several images are taken of this illumination at different shifts across the scene, the direct and global components are computationally reconstructed.

Enhancing OCT depth penetration

The team designed with interferometric imaging systems that improve the sensitivity and depth-penetration of techniques such as optical coherence tomography.

Prototype fiber-interferometric imaging system, using a balanced detector, and combining optical coherence tomography, confocal imaging, and epipolar probing (left); measurements of optically thick homogeneous scattering sample (density σt = 100 mm-1) with different configurations of our system (right).

Prototype fiber-interferometric imaging system, using a balanced detector, and combining optical coherence tomography, confocal imaging, and epipolar probing (left); measurements of optically thick homogeneous scattering sample (density σt = 100 mm-1) with different configurations of our system (right).

Programmable OCT

We developed the imaging systems that combine the flexibility of programmable structured light, with the sensitivity and resolution of optical coherence tomography.

Prototype imaging system that can perform full-frame OCT with arbitrary spatiotemporally coded illumination.

Prototype imaging system that can perform full-frame OCT with arbitrary spatiotemporally coded illumination.

Programmable spectral illumination and imaging

We developed imaging systems that produce arbitrary illumination and sensor sensitivity functions with arbitrary spectral characteristics.

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