scholarly journals Optical versus Radiographic Magnification for Fine-detail Skeletal Radiography

1975 ◽  
Vol 10 (2) ◽  
pp. 160-172 ◽  
Author(s):  
Harry K. Genant ◽  
Kunio Doi ◽  
Jay C. Mall
Radiology ◽  
1974 ◽  
Vol 113 (3) ◽  
pp. 723-725 ◽  
Author(s):  
Kunio Doi ◽  
Harry K. Genant ◽  
Kurt Rossmann

Author(s):  
N.S. Allen ◽  
R.D. Allen

Various methods of video-enhanced microscopy combine TV cameras with light microscopes creating images with improved resolution, contrast and visibility of fine detail, which can be recorded rapidly and relatively inexpensively. The AVEC (Allen Video-enhanced Contrast) method avoids polarizing rectifiers, since the microscope is operated at retardations of λ/9- λ/4, where no anomaly is seen in the Airy diffraction pattern. The iris diaphram is opened fully to match the numerical aperture of the condenser to that of the objective. Under these conditions, no image can be realized either by eye or photographically. Yet the image becomes visible using the Hamamatsu C-1000-01 binary camera, if the camera control unit is equipped with variable gain control and an offset knob (which sets a clamp voltage of a D.C. restoration circuit). The theoretical basis for these improvements has been described.


Author(s):  
G. M. Greene ◽  
J. W. Sprys

The present study demonstrates that fracture surfaces appear strikingly different when observed in the transmission electron microscope by replication and in the scanning electron microscope by backscattering and secondary emission. It is important to know what form these differences take because of the limitations of each instrument. Replication is useful for study of surfaces too large for insertion into the S.E.M. and for resolution of fine detail at high magnification with the T.E.M. Scanning microscopy reduces sample preparation time and allows large sections of the actual surface to be viewed.In the present investigation various modes of the S.E.M. along with the transmission mode in the T.E.M. were used to study one area of a fatigue surface of a low carbon steel. Following transmission study of a platinum carbon replica in the T.E.M. and S.E.M. the replica was coated with a gold layer approximately 200A° in thickness to improve electron emission.


2021 ◽  
Vol 9 (1) ◽  
Author(s):  
Timo Homburg ◽  
Anja Cramer ◽  
Laura Raddatz ◽  
Hubert Mara

AbstractMotivated by the increased use of 3D acquisition of objects by cultural heritage institutions, we were investigating ontologies and metadata schemes for the acquisition process to provide details about the 3D capturing, which can be combined with preexisting ontologies describing an object. Therefore we divided the 3D capturing workflow into common steps starting with the object being placed in front of a 3D scanner to preparation and publication of the 3D datasets and/or derived images. While the proposed ontology is well defined on a coarse level of detail for very different techniques, e.g. Stucture from Motion and LiDAR we elaborated the metadata scheme in very fine detail for 3D scanners available at our institutions. This includes practical experiments with measurement data from past and current projects including datasets published at Zenodo as guiding examples and the source code for their computation. Additionally, the free and Open Source GigaMesh Software Framework’s analysis and processing methods have been extended to provide metadata about the 3D processing steps like mesh cleaning as well as 2D image generation. Finally, we discuss the current limitations and give an outlook about future extensions.


1995 ◽  
Vol 74 (5) ◽  
pp. 2100-2125 ◽  
Author(s):  
D. M. Snodderly ◽  
M. Gur

1. In alert macaque monkeys, multiunit activity is encountered in an alternating sequence of silent and spontaneously active zones as an electrode is lowered through the striate cortex (V1). 2. Individual neurons that are spontaneously active in the dark usually have a maintained discharge in the light. Because both types of discharge occur in the absence of deliberate stimulation, we call them the "ongoing" activity. The zones with ongoing activity correspond to the cytochrome oxidase (CytOx)-rich geniculorecipient layers 4A, 4C, and 6, whereas the adjacent layers 2/3, 4B, and 5 have little ongoing activity. 3. The widths of receptive field activating regions (ARs) are positively correlated with the cells' ongoing activity. Cells with larger ARs are preferentially located in the CytOx-rich (input) layers, and many are unselective for stimulus orientation. However, approximately 90% of the cells in the silent layers are orientation selective, and they often have small ARs. 4. The laminar distribution of selectivity for orientation and direction of movement in alert animals is consistent with earlier results from anesthetized animals, but the laminar distribution of AR widths differs. In alert macaques, the ARs of direction-selective cells in layer 4B and of orientation-selective cells in layer 5 are among the smallest in V1. 5. Our findings indicate that the input layers of V1 (4A, 4C, and 6) have a diversity of AR widths, including large ones. Cortical processing produces receptive fields in some of the output layers (4B and 5) that are restricted to small ARs with high resolution of spatial position. These results imply potent lateral and/or interlaminar interactions in alert animals in early cortical processing. The diversity of AR widths generated in V1 may contribute to detection of fine detail in the presence of contrasting backgrounds--the early stages of figure-ground discrimination.


2006 ◽  
Vol 58 ◽  
pp. 1-22
Author(s):  
Jonathan Wolff

Utilitarianism has a curious history. Its most celebrated founders—Jeremy Bentham and John Stuart Mill—were radical progressives, straddling the worlds of academic philosophy, political science, economic theory and practical affairs. They made innumerable recommendations for legal, social, political and economic reform, often (especially in Bentham's case) described in fine detail. Some of these recommendations were followed, sooner or later, and many of their radical ideas have become close to articles of faith of western liberalism. Furthermore many of these recommendations were made expressly to improve the condition of the deprived, or of oppressed groups. Yet the moral theory which inspired this reforming zeal is, at least officially, utilitarianism, and when we teach this theory to our students we feel it our duty to point out the horrors that could be justified by any theory which assesses the moral quality of actions in terms of the maximization of good consequences over bad. No consequence is so bad that it cannot, in principle, be outweighed by a large aggregation of smaller goods. Hence there are circumstances in which utilitarianism can require slavery, the punishment of the innocent, and redistribution of resources from the poor to the rich, or from the disabled and the sick to the able bodied and healthy. Indeed, in the right circumstances, it can justify pretty much anything you can think of. For all their intelligence and imagination neither Bentham nor Mill seemed to recognise or discuss these catastrophic possibilities.


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