Open Access. Powered by Scholars. Published by Universities.®
- Publication Type
Articles 1 - 3 of 3
Full-Text Articles in Engineering
The Role Of Frame Selection And Bispectrum Phase Reconstruction For Speckle Imaging Through Atmospheric Turbulence, Elizabeth A. Harpold
The Role Of Frame Selection And Bispectrum Phase Reconstruction For Speckle Imaging Through Atmospheric Turbulence, Elizabeth A. Harpold
Theses and Dissertations
Frame selection using quality sharpness metrics have been shown in previous AFIT theses, to be effective in improving the final product of images obtained using adaptive optics. This thesis extends this idea to noncompensated speckle image data. Speckle image reconstruction is simulated with and without frame selection. Speckle images require the processing of hundreds of data frames. Frame selection is a method of reducing the amount of data required to reconstruct the image. A collection of short exposure image data frames of a single object are sorted based on sharpness metrics. Only the highest quality frames are retained and processed …
Analysis Of Ladar Range Resolution Enhancement By Sinusoidal Phase Modulation, Leonard T. Masters, Martin B. Mark, Bradley D. Duncan
Analysis Of Ladar Range Resolution Enhancement By Sinusoidal Phase Modulation, Leonard T. Masters, Martin B. Mark, Bradley D. Duncan
Electro-Optics and Photonics Faculty Publications
The ability of a ladar system to resolve two or more separate returns from a combined echo is related to the effective correlation bandwidth of the pulse emitted by the ladar system. Phase modulation of an outgoing pulse introduces additional frequency components, which increases the effective correlation bandwidth of the pulse and thus improves the range resolution of the system. In this paper, we discuss the general theoretical basis for achieving improved range resolution using a modulated waveform and a matched filter receiver. We then demonstrate these concepts by considering the particular case of improved range resolution for a sinusoidally …
Heterodyne Ladar System Efficiency Enhancement Using Single-Mode Optical Fiber Mixers, Donald K. Jacob, Martin B. Mark, Bradley D. Duncan
Heterodyne Ladar System Efficiency Enhancement Using Single-Mode Optical Fiber Mixers, Donald K. Jacob, Martin B. Mark, Bradley D. Duncan
Electro-Optics and Photonics Faculty Publications
A theoretical performance analysis of a heterodyne ladar system incorporating a single-mode fiber receiver has been performed. For our purposes, the performance parameters of interest are the coupling and mixing efficiency of the ladar receiver, as they relate to the overall system carrier-to-noise ratio. For a receiver incorporating a single-mode fiber mixer, the received and local-oscillator fields are matched both spatially and temporally at the detector, yielding 100% mixing efficiency. We have therefore focused our efforts on determining an expression for the efficiency with which a diffuse return from a purely speckle target can be coupled into the receiving leg …