The world around us is full of colors — like green grass, yellow corn and blue water — but human vision falls short in providing the whole picture. Color cameras record images in a limited color range, leaving much of our world invisible to us. There’s so much more color around us than what the human eye can see, which is where hyperspectral applications come in.
Hyperspectral imaging combines the power of digital imaging with spectroscopy, which is the study of how light interacts with matter. This developing science is changing the way we see practically anything — from plant seeds to the surface of the Earth.
How Hyperspectral Imaging Works
Instead of recording just three wavelengths of light, hyperspectral technology uses specialized sensors that capture the full spectrum of light for each pixel in the image. The sensors divide the light spectrum into a range of contiguous bands — most of which are beyond human visual perception. For example, using hyperspectral applications, doctors can better understand cells, according to the National Center for Biotechnology Information.
Each band is recorded, and hyperspectral applications combine the bands to produce multicolored images in the shape of a cube that contains three dimensions of information about the subject. The image captures a spectral signature for every pixel, which is compared to a database of known image signatures to identify materials, according to researchers at Stanford University.
Think of an aerial scan of a forest. It may be difficult to distinguish between different plant and tree species with similar colors. Northrop Grumman helped resolve this problem with the invention of the Hyperspectral Airborne Terrestrial Imager, which can see more than 700 spectral bands and can accurately depict the solar spectrum ranges of any environment. A hyperspectral imager can “discriminate a maple from an oak, wheat from alfalfa, and is sensitive enough to separate healthy from unhealthy growth.”
Hyperspectral Imaging Captures the Micro and the Macro
From microscopes to satellites and the International Space Station, hyperspectral applications can be deployed just about anywhere. With the systems onboard the ISS, NASA is monitoring cotton crops in California’s San Joaquin Valley and working with the U.S. Forest Service to measure the health and size of forests.
With satellite and aerial images, researchers can spot vegetation and crops under stress due to subtle variations in leaf colors. As the NCBI states, “Diseases can result in changes of transpiration rate, morphology, leaf color and crop density, which in turn affect the optical properties of the plants.”
In the food industry, hyperspectral applications track food quality; they can detect contamination and help identify the source. Pharmaceutical manufacturers have adopted the technique to analyze production quality, detect counterfeit and foreign material, and ensure packaging integrity. Seeds can also be examined to determine whether or not they will successfully sprout, Grind GIS reports.
When someone says, “There’s more to this than meets the eye,” they are telling the truth. By giving us a more powerful way of seeing, hyperspectral imaging can change the game for climate research, population studies, manufacturing, ecosystems monitoring and natural disaster response.