Phenomenon of Dark Space

Author(s):  
Alexander Alexandrovich Antonov
Keyword(s):  
Sensors ◽  
2021 ◽  
Vol 21 (4) ◽  
pp. 1461
Author(s):  
Shun-Hsin Yu ◽  
Jen-Shuo Chang ◽  
Chia-Hung Dylan Tsai

This paper proposes an object classification method using a flexion glove and machine learning. The classification is performed based on the information obtained from a single grasp on a target object. The flexion glove is developed with five flex sensors mounted on five finger sleeves, and is used for measuring the flexion of individual fingers while grasping an object. Flexion signals are divided into three phases, and they are the phases of picking, holding and releasing, respectively. Grasping features are extracted from the phase of holding for training the support vector machine. Two sets of objects are prepared for the classification test. One is printed-object set and the other is daily-life object set. The printed-object set is for investigating the patterns of grasping with specified shape and size, while the daily-life object set includes nine objects randomly chosen from daily life for demonstrating that the proposed method can be used to identify a wide range of objects. According to the results, the accuracy of the classifications are achieved 95.56% and 88.89% for the sets of printed objects and daily-life objects, respectively. A flexion glove which can perform object classification is successfully developed in this work and is aimed at potential grasp-to-see applications, such as visual impairment aid and recognition in dark space.


The observations, of which the results are here given, were made by Mr. Dunlop in the open air, with a 9-feet reflecting telescope, having the clear aperture of the large mirror 9 inches, and fitted up as a meridian telescope; the position of which, and the index error, being ascertained by the passage of known stars. The drawings which accompany the paper were made at the time of observation of the appearances of a great number of nebulæ and clusters, and particularly of the nebulæ major and minor. The paper contains a catalogue and description of 629 nebulæ, arranged in the order of their south polar distance, and in zones for each degree in the order of their right ascension. A few observations are subjoined, describing more particularly the appearance of the nebula minor, which, seen through the telescope, resembles one of the brighter portions of the milky way; of the nebula major, which is brighter, more irregular, and composed of a great number of different parts; and of the dark space on the east side of the cross, or the black cloud, as it is called, which is occasioned by the almost total absence of stars. It is remarked by the author, that neither of the two nebulæ, major and minor, are at present in the place assigned to them by La Caille. He finds also that scarcely any nebulæ exist in a high state of condensation, and very few even in a state of moderate condensation towards the centre. Some have bright points in or near the centre, many of which may be stars; but the greater number of the nebulæ appear only as condensations of the general nebulous matter into faint nebulæ of various forms and magnitudes, generally not well defined; while many of the larger nebulous appearances are resolvable into stars of small magnitudes. But whether nebulæ are universally thus resolvable, is a question of which our instruments are yet incompetent to afford a direct solution, and in the discussion of which we have only analogy as our guide.


2021 ◽  
Vol 7 ◽  
Author(s):  
Huaxu Liu ◽  
Leilei Wang ◽  
Yan Lin ◽  
Xiaofeng Shan ◽  
Min Gao

Objective: To investigate the role of reflectance confocal microscopy (RCM) in the differential diagnosis of hypopigmented mycosis fungoides (HMF) and vitiligo.Methods: Cases with persistent hypopigmented patches, suspicious of early stage vitiligo, or HMF were imaged with RCM. The melanin contents and inflammatory conditions of the epidermis and superficial dermis of the lesions were compared with the same layers of the adjacent skin, and then, the imaged lesions were biopsied and analyzed by histology.Results: 15 cases were enrolled in this study, and based on the RCM findings, there was just slight or moderate reduction of melanin but no melanin absence in the basal cell layer of HMF lesions. The finding of monomorphous weakly refractile, oval to round cells on the basis of vesicle-like dark space was clearly elucidated in the epidermis of the lesions by RCM, which indicates the Pautrier's microabscesses on histopathology. Among those 15 cases, 13 cases were identified as HMF, and the other two cases were vitiligo, based on RCM findings, which were confirmed by histology analysis.Conclusions: The RCM findings correlated well with histology results in the screening of HMF, which indicates the RCM is an important tool in the early detection and differential diagnosis of HMF.


1904 ◽  
Vol 24 ◽  
pp. 496-500
Author(s):  
J. R. Milne

In Spectro-Photometry one of the chief difficulties in making accurate measurements lies in the fact that the eye has to judge of the relative intensities of two spectral bands, which, instead of having their adjacent edges in contact, have them separated by a greater or less dark space. Accordingly, to facilitate a piece of spectrophotometrical work in which I am engaged, a Hüfner's rhomb was tried, which is a special attachment designed to overcome this difficulty. On trial, however, I found that by this means the fault is not entirely removed, although the separating dark space is by this means reduced to a very narrow line. The only alternatives to the Hiifner's rhomb which I know are the devices of Brace, and of Lummer and Brodhun. The first of these depends on the employment of a particular kind of prism in the spectroscope. The other device, due to Lummer and Brodhun, places before the ordinary spectroscope prism a special photometer cube. Both these devices, however, suffer from the drawback that they are unsymmetrical as regards the two beams of light, whose relative intensities it is our object to measure.


1988 ◽  
Vol 63 (1) ◽  
pp. 60-63 ◽  
Author(s):  
Yu. M. Kagan ◽  
C. Cohen ◽  
P. Avivi
Keyword(s):  

2003 ◽  
Vol 90 (3) ◽  
pp. 1728-1736 ◽  
Author(s):  
Jay A. Edelman ◽  
Michael E. Goldberg

Saccade-related discharge in the superior colliculus is greater for saccades made to a spot of light than for saccades in complete darkness. However, it is unclear whether this enhancement is due to the discontinuity of the spot or due to its being a new object of fixation. In these experiments, we examined the saccade-related activity of intermediate-layer neurons in the primate superior colliculus during delayed saccades to the center or corner of a large, bright square, as well as for visual and memory-guided movements to small spots in isolation. The saccade-related discharge for movements made to a local visual landmark present at the time of the saccade, be it a corner of a square or a small spot, was higher than that for saccades made to the center of a square that contained no local visual landmarks within. Moreover, discharge for movements to the center of a square were very similar to that for saccades to blank, dark space. Saccade velocity was similarly dependent on the presence of such a landmark, though less dramatically. The endpoints of saccades directed toward a square's corner were slightly displaced toward the center of the square. Across all neurons, discharge and velocity for saccades to the center of a square increased as the square size was decreased, but were never greater than those for saccades to a small spot of light. These results suggest that both saccade-related discharge in the superior colliculus and saccade metrics are enhanced for movements directed to parts of the visual scene with high contrast, while shifting fixation to a new object is not itself sufficient to elevate discharge and metrics above those of saccades to blank space.


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