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A conoscopic interference pattern or interference figure is a pattern of birefringent colours crossed by dark bands (or isogyres), which can be produced using a geological petrographic microscope for the purposes of mineral identification and investigation of mineral optical and chemical properties.
According to this function, 700 nm red light is only about 0.4% as efficient as 555 nm green light. Thus, one watt of 700 nm red light is "worth" only 2.7 lumens. Because of the summation over the visual portion of the EM spectrum that is part of this weighting, the unit of "lumen" is color-blind: there is no way to tell what color a lumen will ...
Photometria is a book on the measurement of light by Johann Heinrich Lambert published in 1760. [1] It established a complete system of photometric quantities and principles; using them to measure the optical properties of materials, quantify aspects of vision, and calculate illumination.
The Maddox rod is a handheld instrument composed of red parallel plano convex cylinder lens, which refracts light rays so that a point source of light is seen as a line or streak of light. [2] Due to the optical properties, the streak of light is seen perpendicular to the axis of the cylinder. [3] Maddox rod and pen torch used in Maddox rod testing
All of these methods produce images that can be used to calculate the projections (integrals) of the refractive index in the imaging direction. For propagation-based phase contrast there are phase-retrieval algorithms, for Talbot interferometry and refraction-enhanced imaging the image is integrated in the proper direction, and for X-ray ...
Diffraction of light through the eyelashes; Haidinger's brush; Monocular diplopia (or polyplopia) from reflections at boundaries between the various ocular media; Phosphenes from stimulation other than by light (e.g., mechanical, electrical) of the rod cells and cones of the eye or of other neurons of the visual system; Purkinje images.
Photoexcitation is the first step in a photochemical process where the reactant is elevated to a state of higher energy, an excited state.The first law of photochemistry, known as the Grotthuss–Draper law (for chemists Theodor Grotthuss and John W. Draper), states that light must be absorbed by a chemical substance in order for a photochemical reaction to take place.
The goal of the training is for the user to learn to look at the test object in such a way that the Haidinger's brush overlaps the test object (and the viewer is thus now looking at it with their fovea). The reason for such training is that the healthy fovea is far greater in its resolving power than any other part of the retina.