The resolving power of an imaging system in digital lensless Fourier holographic configuration is mainly limited by the numerical aperture of the experimental setup that is defined by both the restricted CCD size and the presence of a beam splitter cube in front of the CCD. We present a method capable of improving the resolution in such a system configuration based on synthetic aperture (SA) ge...

Some recent concert hall designs have incorporated coupled reverberation chambers to the main hall that have stimulated a range of research activities in architectural acoustics. The coupling apertures between two or more coupled-volume systems are of central importance for sound propagation and sound energy decays throughout the coupled-volume systems. In addition, positions of sound sources a...

Aperture synthesis techniques are increasingly being employed to provide high angular resolution images in situations where the object of interest is in the near field of the interferometric array. Previous work has showed that an aperture synthesis array can be refocused on an object in the near field of an array, provided that the object is smaller than the effective Fresnel zone size corresp...

Stomata are microscopic variable aperture pores on the surfaces of leaves. In response to different environmental stimuli, they control the exchange rate of both water vapor and carbon dioxide between the air and the leaf interior, making their role an important determination of the status of plant life on Earth. This study is based on a recently developed stomatal model in which the aperture s...

In the domain of machine vision, the measurement of length is done using cameras where the accuracy is directly proportional to the resolution of the camera and inversely to the size of the object. Since most of the pixels are wasted imaging the entire body as opposed to just imaging the edges in a conventional system, a double aperture system is constructed to focus on the edges to measure at ...

Two new species, Hypancistrus phantasma and Hypancistrus margaritatus, are described based on material from the Rio Negro drainage. Both species are distinguished from congeners by unique color patterns. Hypancistrus phantasma is described from the Rio Uaupes and differs from congeners by having a tan body with small dark spots (vs. dark with light spots or with saddles or stripes). Hypancistru...

Spatial resolution in photoacoustic and thermoacoustic tomography is ultrasound transducer (detector) bandwidth limited. For a circular scanning geometry the axial (radial) resolution is not affected by the detector aperture, but the tangential (lateral) resolution is highly dependent on the aperture size, and it is also spatially varying (depending on the location relative to the scanning cent...

We characterize the acceptance angles of small circular apertures for light collection by simulations and experimental measurements. By examining the full width half maximum acceptance angle as a function of the aperture size, we show that the acceptance angle of a circular aperture reaches a minimum of 67 deg before rebounding around the transition between single mode and multimode transmissio...