Hyperspectral projector evaluates imagers

To evaluate the performance of imaging devices used in cameras, researchers at the National Institute of Standards and Technology (NIST; Gaithersburg, MD, USA) are developing a Hyperspectral Image Projector (HIP).

Oct 1st, 2011
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To evaluate the performance of imaging devices used in cameras, researchers at the National Institute of Standards and Technology (NIST; www.nist.gov; Gaithersburg, MD, USA) are developing a Hyperspectral Image Projector (HIP).

The HIP will enable scientists to project hyperspectral images into camera's sensors, simulating realistic scenes both spectrally and spatially, to test and evaluate sensor performance.

The HIP system is similar to commercially available digital light processing (DLP) projection systems in which projected images are composed from a composite of grayscale images representing each of the RGB colors. In contrast to the DLP system, however, the HIP system can project composites of numerous spectra.

The system's spectral components are generated with a spectral engine composed of dispersive optics and a spatial light modulator such as a digital micromirror device. A spatial engine—composed of a second spatial light modulator—then determines the spatial component for each spectral component. Synchronized operation of both engines ensures that each spectral component is projected sequentially in the correct proportions in each spatial region to create a time-averaged hyperspectral image.

The researchers say that the advantage of the HIP system is not only its ability to project realistic, spectrally, and spatially complex scenes but also the fact that a user has the ability to arbitrarily define and control the spectral distributions at each pixel.

Having proved the concept works in the visible spectrum, the researchers are now continuing to develop the HIP by extending the spectral range into the IR and UV. Portable, rack-mounted prototypes of the system are currently being built.

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