The five-port reflectometer has been recently applied to demodulators and radars, offering an alternative to classic In-Phase/In-Quadrature (I/Q) discriminators. In these applications, calibration of the reflectometer is an important task. Most of the methods developed are suitable for the instrumentation and measurement field and present a high degree of complexity. We propose in this paper a ...

This paper describes the theory and real-time implementation using an active camera platform of a method of planar trajectory recovery, and of the use of those trajectories to facilitate prediction over delays in the visual feedback loop. Image-based position and velocity demands for tracking are generated by detecting and segmenting optical flow within a central region of the image, and a proj...

Retrievals of ice cloud properties using infrared measurements at 3.7, 6.7, 7.3, 8.5, 10.8, and 12.0 μm can provide consistent results regardless of solar illumination, but OPEN ACCESS Remote Sens. 2012, 4 3023 are limited to cloud optical thicknesses τ < ~6. This paper investigates the variations in radiances at these wavelengths over a deep convective cloud system for their potential to exten...

Nearly two years of 2-min resolution data and 7to 21-s resolution data from the CUTLASS Finland HF radar have undergone Fourier analysis in order to study statistically the occurrence rates and repetition frequencies of pulsed ionospheric ̄ows in the noon-sector high-latitude ionosphere. Pulsed ionospheric ̄ow bursts are believed to be the ionospheric footprint of newly reconnected geomagnetic ...

Measurement of motion in transabdominal ultrasound sequences of the small bowel is hampered by the unstructured, textured appearance of the images. We investigate a method of measuring Optical Flow in the sequences, based on an analysis of the spatio-temporal frequency spectrum. The method requires no unrealistic assumptions about the distribution of energy in the frequency spectrum and extends...

Determination of the mass balance of the polar ice sheets requires information on the accumulation rate. Remote sensing methods to determine the accumulation rate are essential in reducing the uncertainty associated with interpolating in situ measurements that are obtained from ice cores and pits. This is essential to reducing the 20% of uncertainty in current accumulation rate maps. Using data...

Partially coherent beam is preferred in many applications, such as free-space optical communications, remote sensing, active laser radar systems, etc., due to its resistance to the deleterious effects of atmospheric turbulence. In this paper, after presenting a historical overview on propagation of optical beams in turbulent atmosphere, we describe the basic theory for treating the propagation ...

site-specific approach is presented to characterize terrain and target visibility and terrain clutter as seen by a shipboard radar in a coastal environment. The method takes into account the location of the ship, the particular terrain topography, the radar parameters, and the propagation effect. The method incorporates atmospheric refractive index conditions surrounding the radar, an optical r...

Radar imaging results for Mercury’s non-polar regions are presented. The dual-polarization, delay-Doppler images were obtained from several years of observations with the upgraded Arecibo S-band (λ12.6-cm) radar telescope. The images are dominated by radar-bright features associated with fresh impact craters. As was found from earlier Goldstone-VLA and pre-upgrade Arecibo imaging, three of the ...

A retrieval algorithm is described to estimate vertical profiles of cirrus-cloud ice water content (IWC) and general effective size Dge from combined lidar and radar measurements. In the algorithm, the lidar extinction coefficient s is parameterized as s 5 IWC[a0 1 (a1/Dge)] and water equivalent radar reflectivity factor Ze is parameterized as Ze 5 C9(IWC/ri) , where a0, a1, C9, and b are const...