Coherent speckle influences the resulting image when narrow spectral line-width and single spatial mode illumination are used, though these are the same light-source properties that provide the best radiance-to-cost ratio. However, a suitable size of the detection pinhole can be chosen to maintain adequate optical sectioning while making the probability density of the speckle noise more normal ...

This paper presents an algorithm for image registration and mosaicing on underwater sonar image sequences characterized by a high noise level, inhomogeneous illumination and low frame rate. Imaging geometry of acoustic cameras is significantly different from that of pinhole cameras. For a planar surface viewed through a pinhole camera undergoing translational and rotational motion, registration...

We discuss the general properties of optical imaging in three-dimensional object domains from an information-theoretic standpoint, expressing system performance in terms of imaging mutual information (IMI). We use IMI to characterize volume holographic imaging, a new optical imaging method with depth discrimination capability. The performance of this holographic method in imaging a simple discr...

An x-ray pinhole camera and a monochromatic K(α) imager are used to measure the interactions of intense femtosecond laser pulses with Cu foil targets. The two diagnostics give different features in the spot size and the laser energy scaling, which are resulted from different physical processes. Under our experimental conditions, the K(α) emission is mainly excited by the fast electrons transpor...

purpose: to determine the screening prevalence of amblyopia, refractive errors and strabismus among 7 to 12 year-old primary school children, tehran, iran, in 2013. methods: this population based cross sectional study was performed on randomly selected 2410 students from 40 primary schools. visual acuity was measured using yang vision tester snellen e-optotype. if visual acuity was ≤20/40, the ...

Dispersive soils which occur in many parts of the world are easily erodible and segregate in water pose serious problems of stability of earth and earth retaining structures. The mechanism of dispersivity of soils is reasonably well understood. However there is simple method to identify the dispersivity of the soils and even more difficult to quantify the dispersivity. Visual classification, At...

Here we report the development of a new scalable and transferable plasma assisted atomic layer deposition (PEALD) process for production uniform, conformal pinhole free NiO with sub-nanometre control on commercial ALD reactor.

A ptychographical coherent diffractive imaging experiment in the water window with focused soft X-rays at 500 eV is reported. An X-ray beam with high degree of coherence was selected for ptychography at the P04 beamline of PETRA III synchrotron radiation source. The beam coherence was measured with the newly developed non-redundant array method, and a coherence length of 4.1 µm and global degre...

We present an instrument dedicated to 3D scanning x-ray microscopy, allowing a sample to be precisely scanned through a beam while the angle of x-ray incidence can be changed. The position of the sample is controlled with respect to the beam-defining optics by laser interferometry. The instrument achieves a position stability better than 10 nm standard deviation. The instrument performance is a...