Compressive imaging spectrometers using coded apertures d. In this paper, we propose an adaptive nonlocal sparse. Apr 25, 2019 this application is related to and claims the benefit of u. The coded aperture modulates the spatial information over all wavelengths in the spectral cube with the coded pattern. These imagers systems often rely on fpa detectors, slms, micromirror devices dmds, and dispersive elements. This work was supported under grant intelnsf vec 1538950. Video rate spectral imaging using a coded aperture snapshot spectral imager ashwin a. This study intends to characterize the spectral and spatial resolution limits of. However, since the reconstruction problem is severely underdetermined, the quality of recovered spectral data is usually limited. Compressive coded aperture spectral imaging ececis. Coded aperture coherent scatter spectral imaging of the breast. The method includes the steps of generating a plurality of xray beams. Dualcamera design for coded aperture snapshot spectral imaging. The coded aperture snapshot spectral imager cassi is an optical.
A dualcamera coded aperture snapshot spectral imaging is proposed 19 to overcome this drawback. The moca is a system that uses a multiplex hologram and a coded aperture to increase the spectral range and throughput of the system over conventional spectrometers while maintaining spectral resolution. Spectral imaging has many different variants of technology and devices, including filtered cameras, whiskbroom and pushbroom scanners, multispectral laser confocal systems, fouriertransform imaging spectrometers, computed tomography imaging spectrometers ctis, imagereplicating imaging spectrometers iris, coded aperture snapshot spectral imagers cassi, and spectral imageslicing. The relay optics relay the image from the plane of the coded aperture to the detector through the. Lensless coded aperture imaging with separable doubly. Adaptation of the same method for neutron imaging has resulted in a number of propitious systems, which could be potentially employed for neutron detection in security and nuclear decommissioning applications. Firstly, the methodology allows the cassi system to use multiple snapshots which permits adjustable spectral and spatial resolution. Extra software modules are available for special functions e. First, the large body of work devoted to coded apertures invariably place the mask significantly far. Jul 01, 20 inspired by the success of coded apertures in spectroscopy 1518, spectral imaging at visible and ultraviolet wavelengths 1921, and an extension to transmission ct, our group previously used a coded aperture for snapshot xray imaging of position and momentum transfer along a pencil beam. Existing coded aperture based lensless systems have two main limitations.
These components included the coded input aperture, the f8. Schematic of coded aperture snapshot spectral imaging cassi. This article surveys compressive coded aperture spectral imagers, also known as. Arce, colored coded aperture design by concentration of measure in compressive spectral imaging, ieee trans. Aperture coding was first introduced by ables 1 and dicke 2 and later popularized by other publications. A postscript version of the complete paper original version, without figures is available 220 kb. Aug 04, 2011 coded aperture camera imaging concept c jean in t zand, 1992, 1996. Ray tracing software was used to optimize the design and layout of the imaging optics and prism. Our computed refocusing method based on image deblurring suffers from deconvolution noise, but we show that typical noise performance is 40 db better than conventional deconvolution of images taken with an open aperture of the same size. The imaging optics image the scene onto the coded aperture. Side information in coded aperture compressive spectral imaging. Farm bae systems spectral solutions, 841 bishop street suite 300, honolulu hawaii 968. Spectral image estimation for coded aperture snapshot spectral imagers ashwin a. The main reason that spectral ct is still a budding technology, according to sahney, is largely a matter of perception.
Pdf coded aperture design for compressive spectral subspace. Characterization of fan beam coded aperture coherent scatter spectral imaging methods for differentiation of normal and neoplastic breast structures, author morris, r and albanese, k and lakshmanan, m and greenberg, j and kapadia, a, abstractnote purpose. Approximate message passing in coded aperture snapshot spectral imaging. Pdf coded hyperspectral imaging and blind compressive. Video rate spectral imaging using a coded aperture snapshot. Osa video rate spectral imaging using a coded aperture. Advacam minipix tpx3 xray diffraction for nondestructive. Scintillator based coded aperture imaging has proven to be effective when applied for x and gammaray detection. We introduce a multiple order coded aperture moca spectrometer. Coded aperture snapshot spectral imaging cassi provides an efficient mechanism for recovering 3d spectral data from a single 2d measurement. Index termscompressive spectral imaging, coded aperture. Philips vanderwall estimates usage between 1030 percent.
The text is regularly updated for new developments in the field. It took place at the hci heidelberg university during the summer term of 20. Sparse representations of dynamic scenes for compressive spectral. Coded aperture snapshot spectral imaging cassi, first in troduced in 2, is an efficient imaging architecture that allows capturing spectral imaging information of a 3d cube with just a single. The wavelengths are usually highenergy radiation such as xrays and gamma rays. Increased photon efficiency is the advantage of caxsi relative to selected volume imaging. Coded aperture correlation holography coach is a recently developed 3d imaging technology. In this paper we propose a novel dualcamera design to improve the performance of cassi while maintaining its snapshot. Approximate message passing in coded aperture snapshot. Compressive spectral imaging csi senses the spatio spectral information of a scene by measuring 2d coded projections on a focal plane array. Compressive imaging spectrometers using coded apertures. Snapshot 2d tomography via coded aperture xray scatter imaging. Coded aperture compressive spectral imagers sense a threedimensional cube by using twodimensional projections of the coded and spectrally dispersed source. Here we describe the use of cassi for spectral imaging of a dynamic scene at video rate.
By blocking radiation in a known pattern, a coded shadow is cast upon a plane. Jin tan, yanting ma, hoover rueda, dror baron, and gonzalo r. The measurements are manifested as a superposition of the coded wavelengthdependent data, with the ambient threedimensional hyperspectral datacube mapped to a twodimensional measurement. Colored coded aperture design by concentration of measure in compressive spectral imaging. Gehm duke university fitzpatrick center for photonics, durham, nc, 27708 abstract a spectral imager provides a 3d data cube in which the spatial information 2d of the image is complemented by spectral information 1d a bout each spatial location. Multiframe coded aperture spectral imaging cassi duke. This paper appeared in a longer version in in t zand 1992. Coded aperture imagers extend the pinhole camera concept, which requires no lenses, has unlimited depth of focus, and can image radiation of any wavelength. Coded aperture based systems using compressive sensing principles 15, 16, 17 have also been studied for image superresolution, spectral imaging, and video capture. Following initial proposals for spectroscopy 8 and imaging 9, coded aperture optical systems focused. Coded aperture snapshot spectral imaging cassi system encodes the 3d hyperspectral image hsi within a. Leveraging the compressive sensing cs theory, coded aperture snapshot spectral imaging cassi provides an efficient solution to recover 3d hyperspectral data from a 2d measurement.
Any motion that does occur can be easily accounted for by an offset in software. In mathematical terms masks were represented as binary arrays with the ones corresponding to the pinholes, and. D student in computer science with over 6 years of experience in scientific research and software development i received the b. Brady1 1department of electrical and computer engineering, duke university, durham, nc 27708. Within the field of spectral imaging, the vast majority of instruments used are. Multiframe coded aperture spectral imaging cassi spectral imaging spectral imaging is a technique that generates a spatial map of spectral variation, making it a useful tool in many applications including environmental remote sensing, military target discrimination, astrophysics and biomedical optics. The authors add an extra imaging path to detect the light intensity and then use twostep. Arce, rank minimization codeaperture design for spectrally selective compressive imaging, ieee trans. Spectral image estimation for coded aperture snapshot. The pixet pro software used for detector operation is provided for free. Introduction of a multihole mask improves the snr while maintaining a good angular resolution of a small diameter, single hole imaging device dicke, 1968. The coded aperture imaging technique is one of the earliest forms of computational photography and has a strong affinity to astronomical interferometry. Single disperser design for coded aperture snapshot spectral. Us patent application for pixelated kedge coded aperture.
Mar 15, 2001 software was developed for image acquisition and computer display of resultant xy images with spectral information. Coded aperture snapshot spectral imager cassi, 2007. The hyperspectral datacube is recovered using a bayesian implementation of blind cs. Fast optimization of coded apertures in xray computed. Asi provides cytogenetic, pathology and research laboratories with brightfield, flouresecence and spectral imaging for cancer testing. The use of colored coded apertures in spectral compressive imaging system cassi have been shown to provide advantages in terms of reconstruction fidelity. Spectral imaging brings new light to ct imaging technology news.
The dualcamera design of cassi, by adding an uncoded panchromatic measurement, enhances the reconstruction fidelity while maintaining the snapshot advantage. The coded aperture approach for radiation detection has its roots in development of scatterhole cameras for x and gammarays. Secondly,the measurement codeword matrices are generated using a pair of. Higher order discretization model for coded aperture spectral. Gpu implementation of the gpsr algorithm for compressive sensing and coded aperture spectral snapshot imaging cassi. Brady a a department of electrical and computer engineering, duke university, durham, nc 27708 b department of computer science, duke university, durham, nc 27708, usa c department of electrical and computer engineering, aristotle university, thessaloniki. We have previously reported on coded aperture snapshot spectral imagers cassi that can capture a full frame spectral image in a snapshot. Blind compressive sensing cs is considered for reconstruction of hyperspectral data imaged by a coded aperture camera. Coded aperture correlation holography features mar 2020. Hyperspectral imaging, like other spectral imaging, collects and processes information from across the electromagnetic spectrum. Colored coded aperture design by concentration of measure in.
In cassi, i the 2d spatial information of a scene is coded by an aperture, ii the coded spatial projections are spectrally shifted by a dispersive element, and. Dualcamera design for coded aperture snapshot spectral. The coded aperture snapshot spectral imager cassi 16 is a compressive spectral imaging system that collects far fewer measurements than traditional spectrometers. It began as a regular inline, twobeam interference holography and has evolved into an interferenceless technique based on a working principle entirely different from techniques of conventional holography.
Adaptive nonlocal sparse representation for dualcamera. A method is provided for generating a spectral computed tomography. Spectral superresolution in colored coded aperture. We describe significant advances in the design of the optical system, system calibration procedures and reconstruction method. Coherent scatter based imaging has shown improved contrast and molecular specificity over conventional digital mammography however the. Coded apertures or coded aperture masks are grids, gratings, or other patterns of materials opaque to various wavelengths of electromagnetic radiation. Coded aperture xray computed tomography caxct is a novel xray. The goal of hyperspectral imaging is to obtain the spectrum for each pixel in the image of a scene, with the purpose of finding objects, identifying materials, or detecting processes. Coded aperture snapshot spectral imaging cassi depicted in fig.