Survey of Hyperspectral Imaging Techniques Michael D Stenner October 30 2009 2009 The MITRE Corporation All rights Reserved Compared Systems Baseline Scanning Filter Baseline Simple Pushbroom Gehm Brady Multiplexed Pushbroom High throughput multiplexed pushbroom hyperspectral microscopy Wagadarikar Brady Single Disperser Single disperser design for coded aperture snapshot spectral imaging Gehm Brady Dual Disperser Single shot compressive spectral imaging with a dual disperser architecture Descour CTIS Computed tomography imaging spectrometer experimental calibration and reconstruction results Mooney Prism Tomographic High throughput hyperspectral infrared camera Gentry ISIS Information Efficient Spectral Imaging Sensor Mohan Raskar Agile Spectrum Imaging Agile Spectrum Imaging Programmable Wavelength Modulation for Cameras and Projectors 2009 The MITRE Corporation All rights Reserved Points of Comparison Data volume Physical volume Architectural impact on acquisition time Computational reconstruction and scaling Photon efficiency noise sensitivity etc Compression Information efficiency Caveats Many quantities like physical volume and reconstruction scaling depend heavily on the specific implementation Interpret these results as expected limits Data quality metric there is none Different techniques can be expected to produce different amounts and types of artifacts These are discussed qualitatively herein 2009 The MITRE Corporation All rights Reserved Baseline Scanning Filter Summary Data Cube Nx x Ny x L Volume 1f D2 Acquisition time scanning Reconstruction None Photon Efficiency 1 L Compression 1 spectral spatial y x tunable filter sensor scan in Scan in using an electronically tunable filter Typically the filter is based on either liquid crystals or acousto optic principles 2009 The MITRE Corporation All rights Reserved Baseline Pushbroom Summary Data Cube Nx x Ny x L Volume 5f D2 Acquisition time Mechanical motion is required between lines resulting in photon dead time but object motion is treated stably Reconstruction None Photon Efficiency 1 Nx Compression 1 spectral spatial y x slit grating sensor scan in x Each row on the sensor provides a spectrum at that y value Scanning in x provides the other spatial dimension 2009 The MITRE Corporation All rights Reserved Gehm Brady Multiplexed Pushbroom Summary Data Cube Nx x Ny x L Volume 5f D2 Acquisition time Mechanical motion is required between lines Reconstruction O NxNy2L Photon Efficiency 1 2 Compression 1 spatial spectral y code x grating sensor scan in y code decode orthogonality requires scene uniformity in y 5 5 5 10 10 10 15 15 15 5 10 15 5 10 15 by sliding code over scene vertically or vice versa one can mix rows to synthesize columns of uniform scene value 5 10 15 2009 The MITRE Corporation All rights Reserved Gehm Brady Multiplexed Pushbroom 2 Reconstruction O NxNy2L O NxNyL x Ny Every point in the data cube is a dot product of length Ny vectors Scanning options Scan scene over code for continuous pushbroom mode requiring slightly more complex data re mapping or Circularly scan code through the field stop for fixed field capture In prototype systems resolution was set by code size to order 6x6 CCD pixels for processing sampling convenience The re binning and digital aberration smile correction was not included in the reconstruction scaling 2009 The MITRE Corporation All rights Reserved Wagadarikar Brady Single Disperser Summary Data Cube Nx x Ny x L Volume 5f D2 Acquisition time Mechanical motion is required between lines if any Reconstruction O NxNyL 3 L1 minimization Photon Efficiency 1 2 Compression 1 L to 1 spatial spectral y x code grating sensor scan in y Identical hardware to Multiplexed Pushbroom Skip scan steps or don t scan at all Reconstruct via L1 minimization Reduced spatial information in single shot mode object pixels imaged to closed code addresses are completely lost 2009 The MITRE Corporation All rights Reserved Gehm Brady Dual Disperser Summary Data Cube Nx x Ny x L Volume 9f D2 Acquisition time Snapshot Reconstruction O NxNyL 3 L1 minimization Photon Efficiency 1 2 Compression 1 L Raw measured frames are spatially isomorphic with scene each pixel is a spectral projection Images removed due to copyright restrictions Source Gehm M E et al Single shot Compressive Spectral Imaging with a Dual disperser Architecture Optics Express 15 no 21 2007 14013 14027 2009 The MITRE Corporation All rights Reserved Single Dual Disperser Comparison single scene after mask 2 2 2 4 4 4 6 6 6 8 8 8 10 10 10 12 12 12 14 14 14 16 16 5 dual measured 10 15 16 5 10 15 2 2 2 4 4 4 6 6 6 8 8 8 10 10 10 12 12 12 14 14 14 16 16 16 5 10 15 5 10 15 5 10 15 5 10 15 2009 The MITRE Corporation All rights Reserved Single Dual Disperser Comparison single scene after mask 2 2 2 4 4 4 6 6 6 8 8 8 10 10 10 12 12 12 14 14 14 16 16 5 dual measured 10 15 16 5 10 15 2 2 2 4 4 4 6 6 6 8 8 8 10 10 10 12 12 12 14 14 14 16 16 5 10 15 5 10 15 5 10 15 16 5 10 15 2009 The MITRE Corporation All rights Reserved Single Dual Disperser Comparison single scene after mask 2 2 2 4 4 4 6 6 6 8 8 8 10 10 10 12 12 12 14 14 14 16 16 5 dual measured 10 15 16 5 10 15 2 2 2 4 4 4 6 6 6 8 8 8 10 10 10 12 12 12 14 14 14 16 16 5 10 15 5 10 15 5 10 15 16 5 10 15 2009 The MITRE Corporation All rights Reserved Descour CTIS Summary Data Cube Nx x Ny x L Volume 4f D2 Acquisition time Snapshot Reconstruction O n3 FBP O n2 log n Fourier Photon Efficiency 1 Compression 1 Images removed due to copyright restrictions Source Descour M and E Dereniak Computed tomography Imaging Spectrometer Experimental Calibration and Reconstruction Results Applied Optics 34 no 22 August 1 1995 4817 4826 Inefficiently uses sensor dead spaces required to avoid overlap Requires P Nx x Ny x L pixels Limited information efficiency missing cone problem Reconstruction approaches have been proposed to improve missing cone extrapolation and model based approaches 2009 The MITRE Corporation All rights Reserved Mooney Prism tomographic Summary Data Cube Nx x Ny x L Volume 4f D2 Acquisition time Scanning Reconstruction O n3 FBP O n2 log n Fourier Photon Efficiency 1 Compression 1 More efficiently uses pixels than CTIS no dead space Requires P Nx x Ny pixels Limited information efficiency missing cone problem Reconstruction approaches have been proposed to improve missing cone extrapolation and model based approaches Image from Mooney JM et al High throughput hyperspectral infrared camera JOSA A 14 no 11