In this evaluation the efficiency of three image signature called angular spectrum, Hough based signature and color histogram are tested The first signature is intrinsic hierarchical (deriving from image frequency spectrum) and than non signature space reduction technique is used. The second is a short signature directly indexed and the last (color histogram) need to be reduced for fast indexin...

The concept of antipodality relative to a closed convex cone K ⊂ Rd has been explored in detail in a recent work of ours. The antipodality problem consists of finding a pair of unit vectors in K achieving the maximal angle of the cone. Our attention now is focused not just in the maximal angle, but in the angular spectrum of the cone. By definition, the angular spectrum of a cone is the set of ...

Focused electromagnetic beams are frequently modeled by either an angular spectrum of plane waves or a partial-wave sum of spherical multipole waves. The connection between these two beam models is explored here. The partial-wave expansion of an angular spectrum containing evanescent components is found to possess only odd partial waves. On the other hand, the partial-wave expansion of an alter...

We present estimates of the angular power spectra of the synchrotron radiation intensity fluctuations at 6 and 20 cm for the shell type supernova remnant Cas A and the filled-centre Crab supernova remnant. We find that the intensity fluctuations of both sources have a power law power spectrum with index −3.24 ± 0.03. This power law power spectrum is consistent with the magnetohydrodynamic turbu...

We present an analysis of the combined effects of tilt and lateral displacement on the orbital angular momentum spectrum of a laser beam. Our theory explains the symmetries and properties of the spectrum under the influence of misalignments. We apply the theory to establish a reliable and efficient method for determining and subsequently eliminating tilt and lateral displacement. An improved te...

We calculate emission rates of a massless state from a highly excited rotating string in perturbative bosonic open string theory. By averaging huge degeneracies of initial string states with specifying the mass and a single component of the angular momentum, we find thermal spectrum in a wide range of the angular momentum. We derive the temperature that characterizes the thermal spectrum from t...

We report on a measurement of the angular spectrum of the CMB between l ≈ 100 and l ≈ 400 made at 144 GHz from Cerro Toco in the Chilean altiplano. When the new data are combined with previous data at 30 and 40 GHz, taken with the same instrument observing the same section of sky, we find: 1) a rise in the angular spectrum to a maximum with δTl ≈ 85 μK at l ≈ 200 and a fall at l > 300, thereby ...

The angular power spectrum of Cosmic Microwave Background (CMB) radiation has proved to be an excellent observation to measure different cosmological parameters. In order to extract cosmological parameters precisely we need to remove foreground contamination as well as detector noise bias. In this paper we present a framework to extract CMB angular power spectrum from the multi-frequency observ...