Phase grating design for a dual-band snapshot imaging spectrometer

Scholl, James F.; Dereniak, Eustace L.; Descour, Michael R.; Tebow, Christopher P.; Volin, Curtis

doi:10.1364/ao.42.000018

Cited by 14 publications

(8 citation statements)

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“…where y ជ ϱ is determined by (11) subject to the condition that the embedded conjugate gradient method, which solves expressions of the form (12), is terminated at the first local minimum of error [in solving (12); see Appendix] or at LIM number of conjugate gradient steps (LIM is a parameter, typically chosen less than 5). Subsequent steps in our heuristic method proceed as follows.…”

Section: E Iterative Heuristic For the Regularized Alternate Problemmentioning

confidence: 99%

“…It is therefore specific to particular systems, like the computed-tomography imaging spectrometer (CTIS), whose noise-free system matrix may sometimes be acceptably approximated by one having the required structure. CTIS systems have wide ranging applications [4 -10]; and have also received attention with respect to research directed at advancing their underlying technology [11][12][13][14][15]. This paper advances mathematical techniques for CTIS image reconstruction under frequently made assumptions.…”

Section: Introductionmentioning

confidence: 99%

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A heuristic technique for CTIS image reconstruction

Vose

Horton

2007

Appl. Opt.

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An iterative method is presented for computed tomography imaging spectrometer (CTIS) image reconstruction in the presence of both photon noise in the image and postdetection Gaussian system noise. The new algorithm, which assumes the transfer matrix of the system has a particular structure, is evaluated experimentally with the result that it is significantly better, for larger problems, than both the multiplicative algebraic reconstruction technique (MART) and the mixed-expectation image-reconstruction technique (MERT) with respect to accuracy and computation time.

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Section: E Iterative Heuristic For the Regularized Alternate Problemmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

A heuristic technique for CTIS image reconstruction

Vose

Horton

2007

Appl. Opt.

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“…1͒. 3 The CTIS system is based on the computed tomographic techniques similar to those used in medical imaging. Computed tomography involves reconstructing a threedimensional data cube from a series of two-dimensional projections of the object.…”

Section: Computed Tomographic Imaging Spectrometermentioning

confidence: 99%

Snapshot dual-band visible hyperspectral imaging spectrometer

Hartke

Dereniak

2007

Opt. Eng

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We describe a proof of concept for a snapshot dual-band visible hyperspectral imaging spectrometer. A commercially available digital camera was integrated into a computed tomographic imaging spectrometer to provide a means for this proof of concept. Two spatially coregistered data cubes covering the blue ͑400 to 500 nm͒ and red ͑600 to 700 nm͒ spectral regions were reconstructed and the results analyzed. We found that the system accurately reconstructs the spectral content of the scene and that the two data cubes are automatically spatially coregistered by virtue of the system design.

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“…This effect was also present in similar work by Jim Scholl. 13 One possible explanation for the discontinuity is the change in the diffraction pattern between the bands. During the design process, we specified the design pattern for each band.…”

Section: Cgh Design Parametersmentioning

confidence: 99%

Non-scanning dual infrared band hyperspectral imaging spectrometer design

2006

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Recent advances in dual band infrared focal plane technology now enable the design and testing of a dual infrared band snapshot imaging spectrometer, the first-ever of its kind. A review of proof of concept results from a dual-visible-band Computed Tomographic Imaging Spectrometer (CTIS) system is presented. The dual-visible system demonstrates that it is possible to reconstruct two spatially co-registered hyperspectral data cubes covering different spectral bands. Based on the visible band CTIS proof of concept, a similar infrared system is now proposed. Critical to the CTIS system is the design of the Computer Generated Holographic (CGH) disperser. Several different (CGH) designs are considered. A first order optical design for the dual infrared band CTIS is presented.Keywords: Dual band, imaging spectrometer, computed tomographic imaging spectrometer BACKGROUND:The recent advances in infrared focal plane technology and the increase in computing power have enabled the creation of a snapshot dual infrared band imaging spectrometer. Infrared focal planes are now being designed and built that consist of detectors that are sensitive to two different spectral regions stacked on top of each other. The advances in computing power have enabled the development of the Computed Tomographic Imaging Spectrometer (CTIS). The CTIS system uses a Computer Generated Holographic (CGH) dispersive optical element to disperse the spectral content of the scene.The goal of all imaging spectrometers is to obtain the spatially registered spectral content of the scene of interest. The product of an imaging spectrometer is a three dimensional data cube. Two of the dimensions of the data cube are the x and y spatial coordinates while the third coordinate is the wavelength of the light intensity in the scene. Conventional imaging spectrometers scan the scene either spatially like a whiskbroom or pushbroom system or spectrally like a filter wheel system. For dynamic scenes the scanning imaging spectrometers may not be able to complete the scan, whether spatially or spectrally, before the scene significantly changes. The CTIS system on the other hand obtains all the information required to reconstruct a data cube in a single snapshot. The spectral content of the scene is dispersed in several radial directions. Each diffracted order is a two dimensional projection of the data cube. The data cube is reconstructed by using tomographic techniques similar to those used in medical computed tomography. Within the data cube we define the discrete three-dimensional differential volume element as a voxel.There are times when we may need to measure the hyperspectral content of the scene over two separate bands. It is possible to split the incoming light in two and reconstruct the two data cubes measured by separated HSI channels independently. The challenge then becomes spatial co-registration of the two cubes. If the focal plane consists of detectors sensitive to the two bands in an interwoven pattern (similar to the commercial approach for three waveb...

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Phase grating design for a dual-band snapshot imaging spectrometer

Cited by 14 publications

References 4 publications

A heuristic technique for CTIS image reconstruction

A heuristic technique for CTIS image reconstruction

Snapshot dual-band visible hyperspectral imaging spectrometer

Non-scanning dual infrared band hyperspectral imaging spectrometer design

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