SummaryDifferential interference contrast (DIC) is frequently used in conventional 2D biological microscopy. Our recent investigations into producing a 3D DIC microscope (in both conventional and confocal modes) have uncovered a fundamental difficulty: namely that the phase gradient images of DIC microscopy cannot be visualized using standard digital image processing and reconstruction techniques, as commonly used elsewhere in microscopy. We discuss two approaches to the problem of preparing gradient images for 3D visualization: integration and the Hilbert transform. After applying the Hilbert transform, the dataset can then be visualized in 3D using standard techniques. We find that the Hilbert transform provides a rapid qualitative pre-processing technique for 3D visualization for a wide range of biological specimens in DIC microscopy, including chromosomes, which we use in this study.
Straightness measurement is a very important technique in the field of mechanical engineering. A particular application for straightness measurement is high-accuracy machining on a diamond-turning lathe. We propose a novel, to our knowledge, optical method for measuring the straightness of motion, and its mathematical analysis is outlined. The technique is based on measurement of the lateral displacement of point images by use of reflection confocal optical systems. The advantages of this method are that (i) the lateral displacements in the direction of the two axes perpendicular to the optical axis can be measured, (ii) the rotation angles around all three axes can be measured, and (iii) reflection optical systems are more compact in length than are transmission optical systems.
A tunable gyrotron is used as the radiation source in a far-forward scattering experiment to investigate the density fluctuations associated with the appearance of discrete Alfven wave (DAW) resonances and kinetic Alfv6n waves (KAWs) in the TORTUS tokamak plasma. A new arrangement of a quasioptical antenna and a Gaussian telescope focuses the gyrotron output into the plasma. Predictions of the scattered amplitude and phase take into account the diffraction and refraction of a Gaussian beam in the plasma. The scattering experiments enable DAW resonances and KAWs to be identified, and their characteristics are in broad agreement with the predictions.
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