Spectral imaging: Difference between revisions

'''Spectral imaging''' is [[imaging]] that uses multiple bands across the [[electromagnetic spectrum]].<ref>{{Cite journal|title=Multispectral hypercolorimetry and automatic guided pigment identification: some masterpieces case studies {{!}} (2013) {{!}} Melis {{!}} Publications {{!}} Spie|url=https://spie.org/Publications/Proceedings/Paper/10.1117/12.2020643?SSO=1|access-date=2021-08-07|website=spie.org|doi=10.1117/12.2020643| s2cid=55155694 }}</ref> While an ordinary camera captures light across three wavelength bands in the visible spectrum, red, green, and blue (RGB), spectral imaging encompasses a wide variety of techniques that go beyond RGB. Spectral imaging may use the [[infrared]], the visible spectrum, the [[ultraviolet]], [[x-ray]]s, or some combination of the above. It may include the acquisition of image data in visible and non-visible bands simultaneously, illumination from outside the visible range, or the use of [[optical filter]]s to capture a specific spectral range. It is also possible to capture hundreds of wavelength bands for each pixel in an image.

 

 

''[[Hyperspectral imaging]]'' is another subcategory of spectral imaging, which combines [[spectroscopy]] and [[digital photography]]. In [[hyperspectral imaging]], a complete [[spectrum]] or some spectral information (such as the [[Doppler shift]] or [[Zeeman splitting]] of a [[spectral line]]) is collected at every pixel in an [[image plane]]. A hyperspectral camera uses special hardware to capture hundreds of wavelength bands for each pixel, which can be interpreted as a complete spectrum. In other words, the camera has a high spectral resolution. The phrase "spectral imaging" is sometimes used as a shorthand way of referring to this technique, but it is preferable to use the term "hyperspectral imaging" in places when ambiguity may arise. Hyperspectral images are often represented as an image cube, which is type of [[data cube]].<ref>{{cite web|url=http://herschel.esac.esa.int/DP_wkshop/4_Gueguen_v2.pdf |title=Visualization and Analysis of Spectral Data Cubes an Hipe toolbox (sic) |website=herschel.esac.esa.int|date=2008-12-04 |accessdate=2017-04-28}}</ref>