Construction and programming of an autonomous focus stacker

Focus stacking is a technique of photomacrography and photomicrography that produces images of small three-dimensional subjects with an arbitrarily high depth of field, unencumbered by diffraction, by combining the in-focus portions of a stack of images of the subject recorded at different focal planes. Software packages are available for postprocessing an image stack into the final image, but the stack images are normally shot either with (typically expensive) automated equipment or by a manual, time-consuming, and error-prone procedures. This paper discusses the construction of an autonomous stacker with inexpensive preassembled electronics and a moderate amount of mechanical construction, and its C++ software.     

图象自动处理显微镜系统

该图象自动处理显微镜系统采用了电荷藕合器件对显微镜系统的涂片(或其它试片)进行了自动测光、自动调焦、自动曝光,以及对涂片(如细胞)进行自动筛选的功能。整个系统由微机控制,设有自动输涂片机械手装置、显微镜工作台自动二维扫描机构、自动测光、自动拍照等装置。微机对CCD器件所得到的图象信息按预定模式进行处理,并由预定程序对其组成机构的每步动作自动控制,达到显微镜系统对图象进行自动分析和处理的目的。     

Methods for obtaining high quality stereoscopic images of microscopic objects

Over 100 years ago Ernst Abbe developed the so-called method of half-moon diaphragms, placed in the exit pupil plane of a binocular microscope, for stereoscopic viewing of microscopic objects. Simplicity of the method being a great advantage, the obvious disadvantages were reduced resolution, azimuthal errors of imaging and failure to control plasticity of the images viewed. Using modern microscopic optics it is possible to avoid these complications, and a complete control of the plasticity of the stereoscopic image as perceived by the observer is achievable while working with medium, strong and the strongest microscope objective lenses. A number of formulae, a nomogram, and a set of tables for calculation of optimal settings are presented in order to promote a range of practical applications, including photomicrography.     

Astronomical hypersensitization techniques applied to photomicrography: Kodak Technical Pan Film 2415

Kodak Technical Pan Film 2415 is a valuable recording medium because of its unusually fine grain and high resolution. Hypersensitization techniques developed by astronomers can increase its normally low speed several-fold in the range of exposures commonly employed in microscopy. The speed gains are even larger for very long exposures such as those encountered in fluorescence work. Troublesome effects from reciprocity failure are virtually eliminated. When active development is added to hypersensitization, well-exposed negatives can be obtained at ISO indexes as high as 1600. As in astronomy, the same general techniques can be applied to a wide variety of emulsions.     

Modelling of damage and failure of glass/epoxy composite plates subject to impact fatigue

An investigation has been carried out to study the impact fatigue damage of glass/epoxy laminated composites. Accumulation of damage, such as matrix cracking, delamination and fibre breakage, with repeated impact of the composite material may reduce the overall stiffness. These damage modes have been combined in a very complicated way to describe damage growth and fracture. A model is proposed for characterising the damage as a function of the normalised impact number. The scalar variable D, which characterises the material damage, is written as a function of the life duration β, using a modified form of the Mankowsky empirical law [Int J Solids Struct 32(11) (1995) 1607]. The macroscopic failure mode and the internal damage in laminated specimens of glass/epoxy as a consequence of impact fatigue are analysed at different levels of incident impact energy. The impact fatigue tests have been conducted on an apparatus built in our laboratory.