In this tutorial, we will introduce how Specim hyperspectral cameras work. There are different ways to collect hyperspectral data. Specim products are line-scan hyperspectral cameras. They collect full spectral and spatial information of the target line by line. Sometimes the term push broom is used for the same technology.
The key components of a line scan hyperspectral camera are an imaging spectrograph, a grayscale camera, and an objective.
All of these components must be optimized for the camera’s wavelength range. You’ll need the objective and the camera when recording a normal black-and-white image. The objective projects the target to the camera sensor, where the image is recorded. To compare this with our book illustration. The result is a one-page black and white leaflet. Once the imaging spectrograph is added, we can record hyperspectral data.
Let’s examine the imaging spectrograph in more detail. The imaging spectrograph contains an input slit, a collimating optics, a dispersive unit, and a focusing lens. The objective forms an image to the input slit. The input slit limits the incoming information. Through it, the information passes only from a single line. Because of this component, these cameras are line-scan cameras.
Input slit is required to measure accurate spectra. The narrower the slit, the more accurate spectra you get. The collimating optics directs and collimates the light from the slit to the dispersive unit. With the dispersive unit, the incoming light spreads into the spectra. The focusing lens is needed to focus the image to the grayscale camera. The grayscale camera is used to measure the intensity of the dispersed light.
Now we have a spectral image. In this image, every row contains intensity information from a different wavelength. The rows provide the full spectrum so that each column contains the spectrum from a single location. This is how the technology can provide answers to questions, what based on the spectrum, and where based on the location. The image of the whole target is recorded line by line with this hyperspectral camera.
This is how line-scan hyperspectral cameras work. The image lines together provide the final spectral image, a data cube.
High data quality and fast operation make this technology suitable for different environments.