The most used way to achieve spectral imaging is to take an image for each desired band, using a narrowband filters. Radiometric accuracy, that sais how accurate is the system in measuring the spectral reflectance percentage.Spectral resolution, that define the smallest spectral variation that the system is able of distinguish.Typically it depends on the number of mega pixels of the photographic camera Spatial resolution, which can be described in terms of number of pixels for the whole image, or in terms of minimum square area distinguishable on the surface.There are a number of parameters to characterize the obtained data: Spectral Imaging Systems are the systems that through the acquisition of one or more images of a subject are able of giving back a spectrum for each pixel of the original images. It also applies to digital and print reproduction, and exhibition lighting design for small and medium cultural institutions. Īpplications of spectral imaging include art conservation, astronomy, solar physics, planetology, and Earth remote sensing. Hyperspectral images are often represented as an image cube, which is type of data cube. 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. In other words, the camera has a high spectral resolution. A hyperspectral camera uses special hardware to capture hundreds of wavelength bands for each pixel, which can be interpreted as a complete spectrum. 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. Hyperspectral imaging is another subcategory of spectral imaging, which combines spectroscopy and digital photography. Industrial, military, and scientific work, however, uses sensors built for the purpose. A scene may be illuminated with NIR light, and, simultaneously, an infrared-passing filter may be used on the camera to ensure that visible light is blocked and only NIR is captured in the image. Many off-the-shelf RGB cameras will detect a small amount of Near-Infrared (NIR) light. Multispectral imaging captures a small number of spectral bands, typically three to fifteen, through the use of varying filters and illumination. It is also possible to capture hundreds of wavelength bands for each pixel in an image. 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 filters to capture a specific spectral range. Spectral imaging may use the infrared, the visible spectrum, the ultraviolet, x-rays, or some combination of the above. 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 is imaging that uses multiple bands across the electromagnetic spectrum. JSTOR ( April 2017) ( Learn how and when to remove this template message).Unsourced material may be challenged and removed. Please help improve this article by adding citations to reliable sources. This article needs additional citations for verification.
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