Abstract: An analysis and mathematical comparison of models underlying the phenomena of brightness and contrast are presented. The concept of self-excitation which has not so far been considered is introduced into the structure of the models. Mach Bands can be described by two essentially different but formally identical mechanisms. The phenomenon allows neither a functional explanation in terms of models presented heretofore nor an answer to the question whether data processing is based in the human visual system on integrating of differentiating of on both.
Abstract: Wavelength-corrected, adaptive optics and their relevance for diagnostic procedures of the human retina are considered. First, it is shown that the compensation of errors of the dioptric apparatus of the eye allows sharp and high-contrast images of retinal elements, such as the photoreceptors, to be generated. This technology is expected to enable on the one hand an improved laser therapy by the application of laser spots of the size of single receptors as well as on the other a further understanding of the mechanisms of vision, in particular of colour vision by using colour stimuli not larger than the cones.…Second, femtosecond laser pulses, emitted from lasers working in the near infrared, based on multiphoton effects allow both imaging and laser effects to be generated which are in the submicron range and which do not cause collateral damage (nanoimaging and nanosurgery). These procedures, related to experimental ophthalmology may be considered a milestone for the research of cell physiology, in particular in the subcellular range.
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Abstract: One may consider the clad silica fibre cutting probe as a cheap alternative of the popular sapphire probe, sharing some of its properties. Made of silica, the scalpels have a fair heat tolerance and may be used without cooling by liquids or gas as is necessary with sapphire blades. The laser scalpel described here is driven (powered) with a 10 W cw Nd:YAG laser energy source (1064 nm) and possesses good cutting and haemostatic properties. It may also be used with lasers emitting other wavelengths. One may assume that a diode laser emitting in the near infrared (800–810 nm) may…have very similar, although not analogous cutting properties when used with the described scalpel.
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