Author: François Alain
Publisher:
ISBN:
Category : Fourier transform spectroscopy
Languages : en
Pages : 175
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Book Description
Imaging Fourier transform spectrometers are becoming popular sensors for hyperspectral remote sensing. To evaluate sensor design artifacts and properties, it is useful to simulate their designs using a radiometrically correct ray-tracing tool. The digital imaging and remote sensing image generation model allows for such design and simulation of sensor properties. Two different design types are evaluated and simulated. Simulated images and the effects of design artifacts are presented, along with the theory allowing their understanding. Results of the simulation of a full scene are shown and help indicate where those sensors can be useful. Finally, recommendations and future improvements to this research are listed.
Author: Erik Kretschmer
Publisher:
ISBN:
Category :
Languages : en
Pages :
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Author:
Publisher:
ISBN:
Category : Aerial reconnaissance
Languages : en
Pages : 184
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Author:
Publisher:
ISBN:
Category : Image processing
Languages : en
Pages : 464
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Author: John Vyvyan Lindner
Publisher:
ISBN:
Category :
Languages : en
Pages :
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Author: Ahmed Mahgoub
Publisher:
ISBN:
Category :
Languages : en
Pages : 114
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Book Description
To obtain a useful or high resolution spectrum from an Imaging Fourier Transform Spectrometer (IFTS), the scene must be stationary for the duration of the scan. This condition is hard to achieve in many cases due to the relative motion between the instrument and the scene during the scan. This relative motion results in multiple data samples at a given pixel being taken from different sub-areas of the scene, and from which (at best) spectra with low accuracy and resolution can be computed. After a review of IFTS, we present motion estimation algorithms to register the frames of data cubes acquired with a moving IFTS, and from which high accuracy and resolution spectra can be retrieved. We use motion estimation algorithms robust to illumination variations, which are suitable for interferograms. Two scenarios are examined. In the first, there is a global motion between the IFTS and the target. In the second, there are multiple targets moving in different directions in the field of view of the IFTS. After motion compensation, we face an off-axis correction problem. The samples placed on the motion corrected optical path difference (OPD) are coming from different spatial locations of the sensor. As a consequence, each sample does not have the same off-axis distortion. We propose a resampling algorithm to address this issue. Finally the calibration problem in the case of moving IFTS is addressed in the last part of the thesis. A calibration algorithm suitable for data cube of moving IFTS is proposed and discussed. We then register the frames and perform the off-axis correction to obtain high resolution spectra. To verify our results, we apply the algorithms on simulated and experimental data. The comparison between the results with the ground-truth shows promising performance. We obtain spectra with resolution similar to the ground truth spectra (i.e., with data acquired when the IFTS and the scene are stationary).
Author: Fourier Transform Spectroscopy Topical Meeting
Publisher:
ISBN: 9781557527448
Category : Fourier transform spectroscopy
Languages : en
Pages : 207
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Author:
Publisher:
ISBN:
Category :
Languages : en
Pages : 17
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Book Description
Fourier transform spectrometers (FTS) using optical sensors are increasingly being used in various branches of science. Typically, a FTS generates a three-dimensional data cube with two spatial dimensions and one frequency/wavelength dimension. The number of frequency dimensions in such data cubes is generally very large, often in the hundreds, making data analytical procedures extremely complex. In the present report, the problem is viewed from a statistical perspective. A set of procedures based on the high degree of inter-channel correlation structure often present in such hyper-spectral data, has been identified and applied to an example data set of dimension 100 x 128 x 128 comprising 128 spectral bands. It is shown that in this case, the special eigen-structure of the correlation matrix has allowed the authors to extract just a few linear combinations of the channels (the significant principal vectors) that effectively contain almost all of the spectral information contained in the data set analyzed. This in turn, enables them to segment the objects in the given spatial frame using, in a parsimonious yet highly effective way, most of the information contained in the data set.
Author: Charles William Pender
Publisher:
ISBN:
Category : Fourier transform spectroscopy
Languages : en
Pages : 242
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Author:
Publisher:
ISBN:
Category :
Languages : en
Pages : 11
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Book Description
The operating principles of an Imaging Fourier Transform Spectrometer (IFTS) are discussed. The advantages and disadvantages of such instruments with respect to alternative imaging spectrometers are discussed. The primary advantages of the IFTS are the capacity to acquire more than an order of magnitude more spectral channels than alternative systems with more than an order of magnitude greater etendue than for alternative systems. The primary disadvantage of IFTS, or FTS in general, is the sensitivity to temporal fluctuations, either random or periodic. Data from the IRIFTS (ir IFTS) prototype instrument, sensitive in the infrared, are presented having a spectral sensitivity of 0.01 absorbance units, a spectral resolution of 6 cm−1 over the range 0 to 7899 cm−1, and a spatial resolution of 2.5 mr.
