PARISS®: Prism and Reflector Imaging Spectroscopy System
PARISS® Analytical Hyperspectral Imaging Microscopy
About Spectral Imaging, Multispectral Imaging And Hyperspectral Imaging
Spectral imaging: a spectrometer acquires spatially resolved spectra with hundreds of contiguous wavelengths over a wavelength range, providing hundreds of wavelength data points per spectrum. Spectral imaging instruments almost always use a diffraction grating or a prism as the wavelength dispersive element.
Multispectral imaging evaluates a field of view (FOV) with non-contiguous wavelengths. Instruments are often based on a liquid crystal tunable filter (LCTF) or an acousto-optic tunable filter (AOTF) in front of a scientific matrix-array camera. These devises often operate with low spectral resolution with up to 100 wavelength data points.
Hyperspectral imaging is a hardware and software system in which spectra presented by objects in a FOV are correlated to spectra in a reference library. Modern hyperspectral imaging systems acquire hundreds to thousands of spectra simultaneously, with each spectrum presenting many hundreds of wavelength data points.
Hyperspectral Imaging Microscopy
Hyperspectral imaging was originally developed for remote Earth sensing in the mid-1970s. Since then, advances in computer technology enabled innovative spectroscopic hardware designs that reduced weight and improved sensitivity.
In 1996 LightForm utilized these advances to pioneer hyperspectral imaging microscopy for biological and medical applications. The goal required that the instrument be sensitive enough to handle low light levels, and compact enough to easily mount as an accessory on almost any microscope without external support.
The solution was found by discarding diffraction grating designs in favor of a prism-based system, originally developed by The Aerospace Corporation* for remote sensing. After redesign, the PARISS imaging spectrograph was ideal for use as a microscope accessory.
A Unique Prism Increases Hyperspectral Imaging Microscopy Sensitivity
The final design resulted in a prism with curved sides that was named using an acronym “PARISS®” (Prism and Reflector Imaging Spectroscopy System”).
The curved sides add optical power to the system to deliver near aberration-free imaging, with 90% efficiency from 365 to 920-nm. The net result is a significant improvement in signal to noise ratio (S/N) when compared to grating solutions. Enhanced sensitivity extended into the near IR where detectors and visible diffraction gratings are at their weakest.
The PARISS imaging spectrograph was then developed into the PARISS hyperspectral microscope
Custom Hyperspectral Software
Custom software shows the location and distribution of all, or selected, spectral-objects on a spectral topographical map.
Unlike most hyperspectral software PARISS utilizes Spectral Waveform Cross Correlation Analysis (SWCCA) in order to best extract signal buried in noise and increase sensitivity. This translates into faster acquisition time even in a low S/N environment.