Abstract: The invention provides a composition and a method for studying skin surface areas with simplified magnifying devices by making a replication of the skin surface area while minimizing irritation to the subject's skin, cracking of the replicas, surface artifacts, and air bubbles in the replicas. The method entails preparing a negative skin surface replica composition by mixing a silicone polysiloxane base and a biocompatible surface tension modifying agent. The mixture is placed in a vacuum desiccator to remove air bubbles and thereafter a curing agent is added to the mixture. An adhesive collar is placed on the subject's skin, which collar surrounds the surface area to be replicated, and thereafter the composition is applied to the skin surface area and the adhesive collar and allowed to dry. The negative skin surface casting is removed from the skin area and is then placed skin side up in a mold cup.

Abstract: The relative height variation and the thickness of a film of an object are simultaneously measured. A first interference pattern is produced for a calibration surface at a first wavelength and detected. Intensities of the first interference pattern are measured and used to compute a first group of phase values for each pixel. Intensity values of a point of the calibration samples are measured and used to compute a corresponding phase. A second interference pattern for the calibration surface is produced at a second wavelength and detected. Intensities of the second interference pattern are measured and used to compute a second group of phase values for each pixel. Intensity values of the point of the calibration surface are measured and used to compute a corresponding phase. A value for the surface height change .DELTA.h is computed by obtaining a linear combination of the corresponding phase values of the data groups.

Abstract: Automatic focusing of an interference microscope is accomplished by directly sensing an interference pattern produced by a white light source with an auxiliary point detector. A beamsplitter intercepts part of the interference beam and directs it to the point detector. A narrow band filter filters light passing through the beam splitter on its way to a main detector array. An objective of the interference microscope is rapidly moved to an initial position between a sample surface and a fringe window by operating a position sensor to sense when the objective is a predetermined safe distance from the sample surface and turning off a motor moving the objective. The objective then moves rapidly from the initial position until the presence of fringes is detected by the point detector. Momentum of the microscope causes the objective to overshoot beyond a fringe window.

Abstract: Automatic focusing of an interference microscope is accomplished by directly sensing an interference pattern produced by a white light source with an auxiliary point detector. A beamsplitter intercepts part of the interference beam and directs it to the point detector. A narrow band filter filters light passing through the beam splitter on its way to a main detector array. A memory lock position of the microscope objective is manually selected and stored. Initially, the objective moves rapidly from the memory lock position until the presence of fringes is detected by the point detector. Momentum of the microscope causes the objective to overshoot beyond a fringe window. The microscope objective then is moved more slowly through the interference window until fringes again are detected; the lower speed results in substantially reduced overshoot. Intensity measurements from the point detector are sensed and stored as the objective moves through the width of the fringe window.