What Is Hyperspectral Imaging?

In an age where more information is better, hyperspectral imaging offers just that. Where a spectrometer measures molecular spectra on one point on a sample, a hyperspectral image measures a spectra at every point in an image. Multispectral imagers typically measure a few spectral bands, as opposed to hyperspectral imagers that can measure very high spectral and spatial features.

The technique acquires both spectral and spatial data at the same time. Let’s look at the line scanning approach used here at SensIR. If a spectrometer slit is imaged and dispersed on a camera array with the slit oriented in the vertical direction, every pixel in that column (vertical) corresponds to a spatial point on the slit. The spectra for that point is present each row of the camera. So with a single capture, we have a one dimensional hyperspectral image in the vertical direction. To get the other dimension in the horizontal direction, The slit needs to be translated across the sample. This is done by either moving the sample or moving the spectrometer. This is why line scanning is well suited for airborne where the spectrometer is moving and process lines where the sample is moving. The spectrometer can also be placed on a gimbal to generate a scan of a stationary object.

What do you do with the data? Just like using library matching and chemometric techniques in spectroscopy, spectra can be matched to components of interest and identified in the two dimensional image.