Mr. James Mathis Profile

James Mathis

at Trex Enterprises Corp

SPIE Involvement:

Author

Publications (2)

Proceedings Article | 26 August 2008 Paper

Laboratory demonstration of a multiple beam Fourier telescopy imaging system

E. Louise Cuellar, Justin Cooper, James Mathis, Paul Fairchild

Proceedings Volume 7094, 70940G (2008) https://doi.org/10.1117/12.798533

KEYWORDS: Signal to noise ratio, Fourier transforms, Reconstruction algorithms, Sensors, Spatial frequencies, Satellites, Modulation, Image restoration, Satellite imaging, Imaging systems

Read Abstract +

Proceedings Article | 30 August 2005 Paper

Field experiment performance of the receiver elements for a Fourier telescopy imaging system

J. Mathis, J. Stapp, E. Cuellar, J. Cooper, A. Morris, P. Fairchild, Dane Hult, Katrina Koski, Lee Ramzel, Marcia Thornton

Proceedings Volume 5896, 58960F (2005) https://doi.org/10.1117/12.639802

KEYWORDS: Mirrors, Receivers, Transmitters, Fourier transforms, Signal to noise ratio, Imaging systems, Sensors, Satellites, Satellite imaging, Wavefronts

Read Abstract +

Fourier telescopy (FT) is an active imaging technique that is a candidate for high resolution imaging systems which can be used to obtain satellite images out to geosynchronous target ranges. Fourier telescopy uses multiple beams that illuminate the target with a fringe pattern that sweeps across it due to a set frequency difference between beams. In this way the target spatial frequency components are encoded in the temporal signal that is reflected from the target. The FT receiver can then be composed of a large area "light bucket" collector, since only the integrated temporal signal is necessary to reconstruct the target image. The GEO Light Imaging National Testbed (GLINT) system was previously designed to obtain satellite images at geosynchronous ranges by using this technique. The "light bucket" receiver was designed use forty heliostats, each having a collection area of ten meters square, and composed of a 16 x 16 grid of two foot square mirrors. The heliostats would redirect the return light from the target onto a large spherical concentrator array composed of hexagonal mirror segments. This concentrator would then focus the return light onto a photomultiplier tube (PMT) detector. The FT Field experiment presented in this paper uses one 10-meter square heliostat and a single PMT, plus a scaled down secondary array to provide the optical elements of the receiver for the FT field experiment. In this paper, we will describe the performance characteristics of the heliostat, secondary, and PMT detector. Performance characteristics include optical wavefront, alignment, and alignment stability of the optical elements. Finally, results will be presented after the receiver was integrated with a transmitter system that provided the modulated FT signal from various targets. Image reconstructions will show that even using low quality "Light bucket" receiver optics and a 1.5 km horizontal path through the atmosphere, the modulated signal can still produce good image quality of the targets. Image reconstruction will also be presented for different SNR values in the received signal.

View contact details

UPDATE YOUR PROFILE

Is this your profile? Update it now.

Sign into your SPIE.org account

Don’t have a profile and want one?

Create an account on SPIE.org

Keywords/Phrases

Search In:

Publication Years