Angular aperture

About: Angular aperture is a research topic. Over the lifetime, 1771 publications have been published within this topic receiving 27257 citations.

Inverted telephoto wide-aperture wide-field infrared lens system

Abstract: Design forms are disclosed for wide-field infrared imaging systems characterized by a large ratio of entrance aperture to focal length, where the limiting aperture stop is located in the converging image space.

Single-lens, single-sensor 3-d imaging device with a central aperture for obtaining camera position

Abstract: A device and method for three-dimensional (3-D) imaging using a defocusing technique is disclosed. The device comprises a lens, a central aperture located along an optical axis for projecting an entire image of a target object, at least one defocusing aperture located off of the optical axis, a sensor operable for capturing electromagnetic radiation transmitted from an object through the lens and the central aperture and the at least one defocusing aperture, and a processor communicatively connected with the sensor for processing the sensor information and producing a 3-D image of the object. Different optical filters can be used for the central aperture and the defocusing apertures respectively, whereby a background image produced by the central aperture can be easily distinguished from defocused images produced by the defocusing apertures.

Single aperture confocal scanning epi-illumination microscope

Abstract: A single aperture confocal scanning epi-illumination microscope comprises an assembly including, in one embodiment, a pair of intermediate lenses to create a second field plane conjugate to the specimen plane in both the incident and reflected light paths, with a single aperture positioned at this second conjugate field plane and controllably scanned through the plane to create the incident light beam as well as to mask the returning light before viewing. In a second embodiment, only a single lens is included in the assembly and the objective lens may be positioned at its correct tube length, a distance substantially shorter, or a non-standard objective lens may be used.

Probability distribution function of the aperture mass field with large deviation theory

Abstract: In the context of tomographic cosmic shear surveys, a theoretical model for the one-point statistics of the aperture mass (Map) is developed. This formalism is based on the application of the large deviation principle to the projected matter density field and more specifically to the angular aperture masses. The latter holds the advantage of being an observable that can be directly extracted from the observed shear field and to be, by construction, independent from the long wave modes. Furthermore we show that, with the help of a nulling procedure based on the so-called BNT transform, it is possible to build observables that depend only on a finite range of redshifts making them also independent from the small-scale modes. This procedure makes predictions for the shape of the one-point Probability Distribution Function of such an observable very accurate, comparable to what had been previously obtained for 3D observables. Comparisons with specific simulations reveal however inconsistent results showing that synthetic lensing maps were not accurate enough for such refined observables. It points to the need for more precise dedicated numerical developments whose performances could be benchmarked with such observables. We furthermore review the possible systematics that could affect such a formalism in future weak-lensing surveys like Euclid, notably the impact of shape noise as well as leading corrections coming from lens-lens couplings, geodesic deviation, reduced shear and magnification bias.