Small-distance position sensing by using holograms of conical waves.

An optical range sensor is suggested that achieves high resolution at small ranges. It is based on the triangulation principle and combines the illumination and detection equipment in a single unit of large aperture. The inclination of the line foci is achieved by using conical waves.

Computer-generated three-dimensional image holograms.

A synthetic generation of three-dimensional image holograms is suggested. The complex amplitude in the hologram is calculated by using the spectrum of plane waves. Specifically, three-dimensional images are composed of planar and inclined two-dimensional distributions.

The effects of Canal Master, Flex-R, and K-Flex instrumentation on root canal configuration.

The purpose of this study was to compare the Canal Master instrument and instrumentation technique (CM/CMI) to Flex-R files used with a "balanced force" technique (FR/BF) and K-Flex files used with a step-back filing technique (KF/SB). Thirty-six root canals in extracted human mandibular molars were equally divided into three groups. The roots were sectioned, then photographed and evaluated before and after instrumentation.

Large objects reconstructed from computer-generated holograms.

In digital holography the first step is the determination of the complex amplitude in the hologram. Large objects can be synthesized from tilted planar segments. In the calculation step, configurations of inclined object and inclined hologram plane are considered.

Computer-generated holograms of 3-D objects composed of tilted planar segments.

The Fresnel diffraction of tilted planar objects is determined. It can be calculated by a Fourier transformation, a coordinate transformation, and a subsequent multiplication by a quadratic phase. Images of 3-D objects are composed by superimposing several planar segments.

Computer generated holograms: cylindrical, conical, and helical waves.

In computer generation of holograms the wave propagation is numerically simulated. Usually this propagation is approximated by the discrete Fourier transform or by geometrical optics. Use of these methods restricts the kind of object which can be recorded synthetically.