WHAT HYPERSPECTRAL IMAGING PROVIDES
In this tutorial we will introduce what kind of data hyperspectral imaging provides. Hyperspectral camera is used to collect a data cube as shown in the previous tutorial. In our example, we compared the data cube to a book.
Let’s discover how this differs from the data and images from other types of cameras.
Digital or smartphone camera shoots the target in 3 colors; red, green and blue, to match the human vision. These colors, which in fact are broad wavelength channels, are equal to the amount of information that is recorded, and the book will have. The result is a small book or leaflet with three pages. The color image that we can see with our eyes is the combination of the pages that we see in the cover.
With hyperspectral camera, our target is recorded from tens to hundreds of narrow color channels, meaning wavelengths. The amount of wavelengths fully depends on what type of hyperspectral camera is being used. In this example the target is recorded in 220 wavelengths throughout the target area. Again, this is the amount of information that our book will have. Every wavelength is presented as a page of the book.
As you compare to the previous, this book is much bigger and it contains much more detailed information about our target.
In most of the cases hyperspectral camera collects information also from the wavelengths invisible from the human vision.
The book cover that we see is constructed from many wavelengths. As said, every page of the book presents its own information. By combining different pages we are able to process different qualities of our target, such as possible plant diseases that are infecting the leaf or the amount of water that the leaf contains.
We are also able to choose any point of the leaf from the book cover and obtain its full, accurate, and contiguous spectrum. This requires that we use all the information of that specific point in every page of the book. We sort of drill a slice of the entire book in order to get the spectral information.
So, hyperspectral camera measures the target in every wavelength that is located in the hyperspectral cameras spectral range, creating a full spectrum for each pixel of the target.
The collected full spectral information is versatile for analysis, detection, and identification of various materials and compounds. And all just with one measurement!