Snapshot hyperspectral imaging explained

Snapshot hyperspectral imaging^[1] is a method for capturing hyperspectral images during a single integration time of a detector array. No scanning is involved with this method, in contrast to push broom and whisk broom scanning techniques. The lack of moving parts means that ^[2] motion artifacts should be avoided. This instrument typically features detector arrays with a high number of pixels.

Development

Although the first known reference to a snapshot hyperspectral imaging device—the Bowen "image slicer"—dates from 1938,^[3] the concept was not successful until a larger amount of spatial resolution was available. With the arrival of large-format detector arrays in the late 1980s and early 1990s, a series of new snapshot hyperspectral imaging techniques were developed to take advantage of the new technology: a method which uses a fiber bundle at the image plane and reformatting the fibers in the opposite end of the bundle to a long line,^[4] viewing a scene through a 2D grating and reconstructing the multiplexed data with computed tomography mathematics,^[5] the (lenslet-based) integral field spectrograph,^[6] a modernized version of Bowen's image slicer.^[7] More recently, a number of research groups have attempted to advance the technology in order to create devices capable of commercial use. These newer devices include the HyperPixel Array imager a derivative of the integral field spectrograph,^[8] a multiaperture spectral filter approach,^[9] a compressive-sensing–based approach using a coded aperture,^[10] a microfaceted-mirror-based approach,^[11] a generalization of the Lyot filter,^[12] and a generalization of the Bayer filter approach to multispectral filtering.^{[13] [14]}

Slitless spectroscopy can be considered a basic snapshot hyperspectral imaging technique. Spaced point-like sources, such as a sparse field of stars, is a requirement to avoid spectrum overlap on the detector.

Applications

While snapshot instruments are featured prominently in the research literature, none of these instruments have seen wide adoption in commercial use (i.e. outside the professional astronomical community) due to manufacturing limitations. Thus, their primary venue continues to be astronomical telescopes. One of the main reasons for the popularity of snapshot devices in the astronomical community is that they offer large increases in the light collection capacity of a telescope when performing hyperspectral imaging.^{[15] [16]} Recent applications have been in soil spectroscopy^[17] and vegetation sciences.^[18]

See also

• Imaging spectroscopy
• Multi-spectral image
• Chemical imaging
• Imaging spectrometer
• Spectral imaging
• Computed tomography imaging spectrometer
• Video spectroscopy

Notes and References

1. Web site: Hagen. Nathan. Kudenov. Michael W.. Review of snapshot spectral imaging technologies. Spie. Digital Library. Optical Engineering. 2 February 2017. bot: unknown. https://web.archive.org/web/20150920195938/http://opticalengineering.spiedigitallibrary.org/article.aspx?articleid=1743003. 20 September 2015.
2. Snapshot Techniques, Michels R. "16 Handbook of Optical Components", Hanser Verlag 445-464: 978-3-446-44115-6(2014).
3. I. S. Bowen, "The image slicer, a device for reducing loss of light at slit of stellar spectrograph", Astrophysical Journal 88: 113-124 (1938).
4. S. C. Barden and R. A. Wade, "DensePak and spectral imaging with fiber optics", in Fiber Optics in Astronomy, Astronomical Society of the Pacific Conference Series 3: 113-124 (1988).
5. Takayuki Okamoto and Ichirou Yamaguchi, "Simultaneous acquisition of spectral image information", Optics Letters 16: 1277-1279 (1991).
6. R. Bacon, G. Adam, A. Baranne, G. Courtes, D. Dubet, J. P. Dubois, "3D spectrography at high spatial resolution. I. Concept and realization of the integral field spectrograph TIGER," Astronomy and Astrophysics Supplement 113: 347-357 (1995).
7. L. Weitzel, A. Krabbe, H. Kroker, N. Thatte, L.E. Tacconi-Garman, M. Cameron and R. Genzel, "3D: The next generation near-infrared imaging spectrometer," Astronomy and Astrophysics Supplement 119: 531-546 (1995).
8. Bodkin, A., Sheinis, A., Daly, J., Beaven, S., Weinheimer, J. “Snapshot Hyperspectral Imaging – the Hyperpixel Array Camera”, Proc. SPIE, 7334-17, (2009)
9. S. A. Mathews, "Design and fabrication of a low-cost, multispectral imaging system," Applied Optics 47: F71-F76 (2008).
10. A. Wagadarikar, R. John, R. Willett, and D. Brady, "Single disperser design for coded aperture snapshot spectral imaging," Applied Optics 47: B44-B51 (2008).
11. L. Gao, R. T. Kester, T. S. Tkaczyk, "Compact Image Slicing Spectrometer (ISS) hyperspectral fluorescence microscopy", Optics Express 17: 12293-12308 (2009).
12. A. Gorman, D. W. Fletcher-Holmes, and A. R. Harvey, "Generalization of the Lyot filter and its application to snapshot spectral imaging," Optics Express 18: 5602-5608 (2010)
13. N. Gupta, P. R. Ashe, and S. Tan, "Miniature snapshot multispectral imager", Optical Engineering 50: 033203 (2011).
14. I. J. Vaughn, A. S. Alenin, and J. S. Tyo, "Focal plane filter array engineering I: rectangular lattices", Optics Express 25: 10 (2017).
15. M. A. Bershady, "3D spectroscopic instrumentation", to appear in 3D Spectroscopy in Astronomy, XVII Canary Island Winter School of Astrophysics, eds. E. Mediavilla, S. Arribas, M. Roth, J. Cepa-Nogue, and F. Sanchez, Cambridge University Press (2009).
16. N. Hagen, R. T. Kester, L. Gao, and T. S. Tkaczyk, "Snapshot advantage: a review of the light collection improvement for parallel high-dimensional measurement systems", Optical Engineering 51: 111702 (2012).
17. Jung, A., Vohland, M. and Thiele-Bruhn, S. "Use of a Portable Camera for Proximal Soil Sensing with Hyperspectral Image Data," Remote Sensing, 7(9): 11434-11448 (2015).
18. Aasen, H., Burkart, A., Bolten, A. and Bareth, G., "Generating 3D hyperspectral information with lightweight UAV snapshot cameras for vegetation monitoring: From camera calibration to quality assurance." ISPRS Journal of Photogrammetry and Remote Sensing 108:, 245-259 (2015).