Divergent rays of light Indistinct vision is most commonly caused by errors of refraction. Doctors do not often have to deal with this problem because patients are usually prescribed glasses by an optometrist. It is extremely important, however, to ask the question: "Is this patient's poor vision caused by a refractive error?" The use ofa simple "pinhole" made in a piece ofcard will help to det...

A 30 µm pinhole is introduced in the intermediate focus of the SIM beamline at the Swiss Light Source to improve the spot size at the second downstream focus, which is used here for liquid jet X-ray photoelectron spectroscopy experiments. The 30 µm pinhole reduces the beam dimensions from 250 (v) × 100 (h) µm to 75 × 45 µm for a vertical exit slit of 100 µm. The smaller X-ray spot results in a ...

An algorithm for image registration and mosaicing on underwater sonar image sequences characterised by a high noise level, inhomogeneous illumination and low frame rate is presented. 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 can be...

We report an experiment to demonstrate the crucial effect of the so-called background reservoir during the propagation of femtosecond laser pulses in air. The background reservoir was blocked by allowing only the filament to pass through a pinhole generated by the filament itself in an aluminum foil. We observed that the filamentation process is terminated immediately after the pinhole. Consequ...

Emission at 13.2 nm from the 4d S0 -4p P1 laser transition of Ni-like Cd was observed in a cadmium vapor plasma column excited by a high-current capillary discharge. The dynamics of the plasma were studied using time-resolved soft x-ray pinhole images and hydrodynamic simulations. The pinhole images show that the plasma column maintains a good symmetry up to the time of maximum compression. Fif...

A new micro-XRF instrument was developed in combination with an atomic force microscope (AFM). A small pinhole of 5 or 10 μm was made on the AFM cantilever. The center of the micro X-ray beam generated by a polycapillary X-ray lens was passed through the pinhole. The present experiment demonstrated that the size of the original X-ray beam of 48 μm produced by the polycapillary lens was reduced ...

We experimentally demonstrate an all-diffractive optical setup for digital lensless holographic microscopy with easy wavelength line selection and micrometric resolution. In the proposed system, an ultrashort laser pulse is focused with a diffractive lens (DL) onto a pinhole of diameter close to its central wavelength to achieve a highly spatially coherent illumination cone as well as a spectra...

Tantalum-178 is a short-lived radionuclide (Tm = 9.3 min.) and emits primarily 56to 64-keV characteristic x-rays. We have determined the imaging characteristics with this radionuclide and a large-field-of-view Anger camera. With a pinhole collimator, good spatial resolution is possible with Ta-178, although the image quality is superior with Tc-99m under comparable conditions. Spatial resolutio...