Spectral Imaging Camera

EE 134 Final Project

This was a final project for EE 134: Introduction to Photonics. Logan Herrera, Gary Lee, and I built a bench-top spectral imaging system.

You can find our poster here.

Spectral Imaging

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We designed a low-cost spectral imaging system based on off-the-shelf camera lenses and an unmodified consumer camera. Computed tomographic algorithms convert the captured image into a single data structure with spatial and spectral dimensions. After constructing the system, we used light sources and a variety of color filters to assess the functionality of our instrument.

Light incident on a diffraction grating is split and diffracted in different directions as described by the grating equation d sinθ = mλ. Diffracted beams of different wavelengths will be mapped to different spatial points on the image plane.

We used unmodified Nikon lenses, inexpensive diffraction gratings, and a Nikon D7100 camera. To test our setup, we used a fluorescent light tube. We also placed several different color filters (Rosco Roscolux) in front of the light to observe changes in spectral information presented in the first-order fringes. To exhibit the system’s capability of capturing both spatial and spectral information, we used an LED array (Seeed Studio) as a column of different colored lights.

Because the image data is two-dimensional, it is possible to fully reconstruct the component wavelengths independently for each point along the slit aperture.

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