Ambiguities in Colour Constancy and Shape from Shading

Perception ◽  
1997 ◽  
Vol 26 (4) ◽  
pp. 531-541 ◽  
Author(s):  
Torbjörn Jakobsson ◽  
Sten Sture Bergström ◽  
Karl-Arne Gustafsson ◽  
Elena Fedorovskaya
Keyword(s):  
Shape From Shading ◽  
The Other ◽  
Colour Constancy ◽  
Stimulus Situation ◽  
Descriptive Data ◽  
Visual Phenomenon ◽  
Sharp Edges ◽  
Grey Colour ◽  
Surprising Observation

A new visual phenomenon—called the AMBEGUJAS phenomenon—is presented, together with some descriptive data from two initial exploratory experiments. The phenomenon is basically one of shape from shading, but ambiguous as to both shape and colour. There are two spontaneously alternating and mutually exclusive perceived 3-D shapes, and—as the most surprising observation—the colour impressions of these two shapes are markedly different. The stimulus situation is very simple with two differently coloured illuminations (with sharp edges) adjacently cast onto a flat, grey striped surface. In one 3-D shape almost the whole chromatic content disappears, and the surface goes towards its veridically grey colour. In the other the perceived object assumes the two illumination colours as clear surface colours. The decolorised percept is interpreted as a striking example of colour constancy: a perceptual solution with the classical ‘discounting of the illuminant’. Experiments show that the phenomenon is robust and appears in varying display layouts and different combinations of chromatic illuminations.

A Colour Constancy Phenomenon Related to Perceived 3-D Shape

Perception ◽  
1996 ◽  
Vol 25 (1_suppl) ◽  
pp. 11-11
Author(s):  
S S Bergström ◽  
K-A Gustafsson ◽  
T Jakobsson
Keyword(s):  
Shape From Shading ◽  
Lower Half ◽  
The Other ◽  
Colour Filter ◽  
Colour Constancy ◽  
Psychophysical Data ◽  
Roof Shape

Flat, rectangular displays consisting of 2, 3, 4, or 6 vertical grey stripes, alternately light and dark gray (NCS 3500 and NCS 6000, respectively) were presented one at a time illuminated by two identical projectors. One projector illuminated the upper half of the display through a yellowish colour filter (Strand Golden Amber), and the other one illuminated the lower half through a bluish colour filter (Kodak Wratten 80 A). The display appeared ambiguous, periodically and spontaneously shifting between two distinct 3-D shape percepts, A and B. Display A appeared vertically folded along the reflectance edges (‘shape from shading’, where the dark fields appeared to be attached shadows). The colours were quite saturated yellow and blue surface colours. There was no colour constancy; Display B appeared horizontally folded along the illumination edge like a roof (‘shape from shading’, where one of the illuminations appeared to be an attached shadow). The display now appeared very desaturated, even achromatic, but in a ‘warm’ illumination. The colour constancy was almost complete. The phenomenon is demonstrated with a slide, and some psychophysical data on the colour desaturation and on the frequency of shifts between the two percepts are reported as well as some observations on combinations of illuminant colours other than yellow and blue. The reported colour constancy phenomenon is discussed in relation to an earlier presented model for the perception of illumination, colour, and depth [S S Bergström, 1994, in Lightness, Brightness, and Transparency Ed. A Gilchrist (Hillsdale, NJ: Lawrence Erlbaum Associates)].

scholarly journals Constraining planetesimal stirring: how sharp are debris disc edges?

2021 ◽  
Vol 503 (4) ◽  
pp. 5100-5114
Author(s):  
Sebastian Marino
Keyword(s):  
Surface Density ◽  
Semimajor Axis ◽  
Rayleigh Distribution ◽  
Outer Edge ◽  
The Other ◽  
Dust Production ◽  
Array Data ◽  
Disc Surface ◽  
Sharp Edges ◽  
Good Agreement

ABSTRACT The dust production in debris discs by grinding collisions of planetesimals requires their orbits to be stirred. However, stirring levels remain largely unconstrained, and consequently the stirring mechanisms as well. This work shows how the sharpness of the outer edge of discs can be used to constrain the stirring levels. Namely, the sharper the edge the lower the eccentricity dispersion must be. For a Rayleigh distribution of eccentricities (e), I find that the disc surface density near the outer edge can be parametrized as tanh [(rmax  − r)/lout], where rmax  approximates the maximum semimajor axis and lout defines the edge smoothness. If the semimajor axis distribution has sharp edges erms is roughly 1.2lout/rmax  or erms = 0.77lout/rmax  if semimajor axes have diffused due to self-stirring. This model is fitted to Atacama Large Millimeter/submillimeter Array data of five wide discs: HD 107146, HD 92945, HD 206893, AU Mic, and HR 8799. The results show that HD 107146, HD 92945, and AU Mic have the sharpest outer edges, corresponding to erms values of 0.121 ± 0.05, $0.15^{+0.07}_{-0.05}$, and 0.10 ± 0.02 if their discs are self-stirred, suggesting the presence of Pluto-sized objects embedded in the disc. Although these stirring values are larger than typically assumed, the radial stirring of HD 92945 is in good agreement with its vertical stirring constrained by the disc height. HD 206893 and HR 8799, on the other hand, have smooth outer edges that are indicative of scattered discs since both systems have massive inner companions.

scholarly journals Course designs in Meebook’s course builder: analysis of 102 course designs

2018 ◽  
Vol 10 (18) ◽  
Author(s):  
Stefan Ting Graf ◽  
Stig Toke Gissel ◽  
Marie Falkesgaard Slot
Keyword(s):  
Systematic Study ◽  
Course Design ◽  
Learning Objectives ◽  
The Other ◽  
Digital Learning ◽  
Multimodal Learning ◽  
Local School ◽  
Descriptive Data ◽  
Learning Platform ◽  
Learning Platforms

In this article, we present the first systematic study of how teachers design courses in the newly implemented digital learning platforms in Denmark. The study is based on the collection and double coding of the 102 most downloaded course designs in the learning platform Meebook. The descriptive data is analysed in the light of Meebook’s affordances, previous research and didactical theory. Our analysis focusses on the three main intentions of the introduction of learning platforms for K9-schools. This concerns firstly the use of learning objectives and their assessment, secondly the use of the platform in relation to the intention of sharing teacher-created course designs and thirdly the question of how teachers deal with the integration of multimodal learning materials in the course design. On one hand, the course builder in Meebook seems to affect teachers’ course designs strongly, and on the other hand, the course builder does not facilitate didactical reasoning and coherence. The results of the study have potential implications for platform designers, local school authorities and headmasters who deal with the implementation of platforms as well as teachers that daily use such course builders for teaching and the students’ learning.

scholarly journals II.—On a Collection of Trilobites from the Upper Cambrian of Shantung, North China

1905 ◽  
Vol 2 (6) ◽  
pp. 251-255 ◽  
Author(s):  
Henry Woodward
Keyword(s):  
North China ◽  
The Other ◽  
Upper Cambrian ◽  
Small Base ◽  
Grey Colour

Continuing the notice of Herr H. Monke's paper on the Trilobite-bearing limestone slabs of Yen-tsy-yai, the author observes:—The very dense and solid, slightly arenaceous limestones of Yen-tsy-yai consist of horizontal slabs (from 1–2½ cm. thick) of a dark bluish-grey colour, [p. 109] Whilst showing no traces of fossils in their interior, the limestone slabs are on one side (as shown on pl. ix) often completely covered with the remains of Trilobite carapaces, besides which are found only isolated very minute shells of Brachiopoda. Between them are here and there irregular, lengthened furrows, which may be the tracks of the Trilobites; on the corresponding opposite pails of the slabs are similarly shaped vermiform protuberances. It follows that the fossiliferous side is to be considered as the natural upper part of the slabs. In a certain number of the slabs either both sides or one only are covered besides by a thin argillaceous stratum, which equally contains, though less frequently, delicate remains of fossils; in all the other slabs the fossils present themselves en relief and often rest on a small base of limestone, and therefore convey the impression of having been originally covered by a thin argillaceous stratum, which later on was washed away by water.

Measurements of Colour Constancy by Using a Forced-Choice Matching Technique

Perception ◽  
1996 ◽  
Vol 25 (2) ◽  
pp. 229-241 ◽  
Author(s):  
David I Bramwell ◽  
Anya C Hurlbert
Keyword(s):  
Forced Choice ◽  
The Other ◽  
Two Dimensional ◽  
Colour Constancy ◽  
Test Patch ◽  
Complex Scenes ◽  
Matching Technique ◽  
Chromatic Sensitivity ◽  
Colour Appearance ◽  
Method Of Constant Stimuli

Colour constancy is typically measured with techniques involving asymmetric matching by adjustment, in which the observer views two scenes under different illuminants and adjusts the colour of a reference patch in one to match a test patch in the other. This technique involves an unnatural task, requiring the observer to predict and adjust colour appearance under an illumination shift. Natural colour constancy is more a simple matter of determining whether a colour is the same as or different from that seen under different illumination conditions. There are also technical disadvantages to the method of matching by adjustment, particularly when used to measure colour constancy in complex scenes. Therefore, we have developed and tested a two-dimensional method of constant-stimuli, forced-choice matching paradigm for measuring colour constancy. Observers view test and reference scenes haploscopically and simultaneously, each eye maintaining separate adaptation throughout a session. On each trial, a pair of test and reference patches against multicoloured backgrounds are presented, the reference patch colours being selected from a two-dimensional grid of displayable colours around the point of perfect colour constancy. The observer's task is to respond “same” or “different”. Fitting a two-dimensional Gaussian to the percentage of “different” responses yields (1) the subjective colour-constancy point, (2) the discrimination ellipse centred on this point, and (3) a map of changes in sensitivity to chromatic differences induced by the illuminant shift. The subjective colour-constancy point measured in this way shows smaller deviations from perfect colour constancy—under conditions of monocular adaptation—than previously reported; discrimination ellipses are several times larger than standard MacAdam ellipses; and chromatic sensitivity is independent of the direction of the illuminant shift, for broad distributions of background colours.

scholarly journals Costume Characteristics of Children Creation Dance in Kindergarten at Buleleng Bali

2015 ◽  
Vol 15 (2) ◽  
Author(s):  
Langen Bronto Sutrisno ◽  
Luh Suartini ◽  
I Gusti Made Budiarta
Keyword(s):  
Qualitative Method ◽  
The Other ◽  
General View ◽  
Descriptive Data ◽  
Other Hand ◽  
Close Proximity ◽  
Aesthetic Aspect ◽  
The Aesthetic

Study related to characteristics of costumes worn in Children Creation Dance in kindergarten at Buleleng, Bali is aiming at (1) understanding the characteristics of children creation dance costume in kindergarten at Buleleng, Bali, (2) understanding the aesthetic characteristic of costume of children creation dance in kindergarten at Buleleng, Bali. The research employed qualitative method while the discussion part was presented in descriptive. Data was collected through observation, interview, literature, as well as documentation study. In a general view, characteristic of the costume was still in close proximity to the tradition but some others characteristics have quiet different to the tradition. Aesthetic aspect in dance costume that has adjacency to the tradition is shown in patterned costume, especially the use of kamen prada. The use of colour tends to be bright and cold which may show the atmosphere of happiness and assurance. On the other hand, the characteristics of costume is not traditional tends to emphasize dots and stripes. The impression of dots is shown in the use of sequin while the stripe impession is shown in fabric colour boundaries. In addition, the colours chosen for this type of costume are considerably similar to the colour chosen in traditional costume of creation dance which are bright and cold and give the impression of happiness and assurance.

scholarly journals THE STYLE USED BY STUDENTS IN LEARNING VOCABULARY

2018 ◽  
Vol 4 (2) ◽  
pp. 62
Author(s):  
Fithria Ulfani Yuliatin
Keyword(s):  
Learning Styles ◽  
Learning Style ◽  
Qualitative Data ◽  
Visual Learning ◽  
The Other ◽  
Applied Learning ◽  
Descriptive Data ◽  
Qualitative Descriptive ◽  
Student Learning Style ◽  
Mastery Criteria

The purpose of this study is to describe the application of Learning Styles in the vocabulary used by students of SMAN 1 Sakra Timur. To know the percentage of student learning style in vocabulary. Students of grade 2 IPA 1 are less in applied learning styles, students are more sitting and silent, whether they understand what is described or not. In keeping the results of research, conducted data collection using qualitative descriptive. Data obtained from the results of vocabulary and questionnaire tests. On the other hand, the qualitative data comes from student observations as well. Then the data can be seen that students have problems with the vocabulary, from 37 students who are able to achieve it consists of 15 students (40%) able to achieve the Minimum Mastery Criteria with qualifications consisting of 5 students (14%) to Prima, 9 students (24% to Very good, and 10 students (27%) became good, while there were 13 students (35%) who were unable to achieve minimum mastery with poor or failing qualifications. For percentage of learning style preferred by students to learn to use visual learning style, (89%) SS, 3 (8%) S, 1 (2%) TT and nobody chose disagree and strongly disagree. In addition, from the observation, Students are less active to respond to lessons taught due to lack of force learning applied by the teacher.

scholarly journals Comparative Aspects of Annelid Regeneration: Towards Understanding the Mechanisms of Regeneration

Genes ◽  
2021 ◽  
Vol 12 (8) ◽  
pp. 1148
Author(s):  
Roman P. Kostyuchenko ◽  
Vitaly V. Kozin
Keyword(s):  
Tissue Regeneration ◽  
Molecular Basis ◽  
The Other ◽  
Whole Body ◽  
Descriptive Data ◽  
Transcriptomic Data ◽  
Levels Of Organization ◽  
Ability To Regenerate ◽  
Different Levels

The question of why animals vary in their ability to regenerate remains one of the most intriguing questions in biology. Annelids are a large and diverse phylum, many members of which are capable of extensive regeneration such as regrowth of a complete head or tail and whole-body regeneration, even from few segments. On the other hand, some representatives of both of the two major annelid clades show very limited tissue regeneration and are completely incapable of segmental regeneration. Here we review experimental and descriptive data on annelid regeneration, obtained at different levels of organization, from data on organs and tissues to intracellular and transcriptomic data. Understanding the variety of the cellular and molecular basis of regeneration in annelids can help one to address important questions about the role of stem/dedifferentiated cells and “molecular morphallaxis” in annelid regeneration as well as the evolution of regeneration in general.

scholarly journals NILAI BUDAYA MAPPANO’ DALAM PELAKSANAAN AQIQAH PADA MASYARAKAT BULISU KECAMATAN BATULAPPA

2018 ◽  
Vol 11 (1) ◽  
pp. 1-29
Author(s):  
Marhani Marhani
Keyword(s):  
Cultural Values ◽  
Empirical Data ◽  
The Other ◽  
Descriptive Data ◽  
Islamic Theology ◽  
Other Hand ◽  
Qualitative Descriptive ◽  
The One ◽  
The Guardian

This paper discusses the understanding of mappano culture values in the implementation of aqiqah in the Bulisu community of Kassa Village, Batulappa District in terms of Islamic theology. The aim of obtaining empirical data on the implementation of the mappano tradition and the cultural values contained in the implementation of the tradition by the Bulisu community. Using qualitative descriptive data in this paper concluded that the mappano tradition was implemented after the aqiqah event was finished. In practice, the mappano tradition 'on the one hand is in line with religious teachings that is to aim and return everything to Allah SWT. However, on the other hand some of which are carried out in the mappano' tradition are contrary to the teachings of religion by having the belief that the guardian of water is a temporary crocodile religious teachings that all that is in heaven and on earth is absolutely the property of Allah SWT.

Taxonomy and biostratigraphic significance of Icriodus orri Klapper and Barrick and related Middle Devonian conodont species

2016 ◽  
Vol 90 (6) ◽  
pp. 1181-1196
Author(s):  
Katarzyna Narkiewicz ◽  
Pierre Bultynck
Keyword(s):  
North American ◽  
Posterior Part ◽  
Sensu Stricto ◽  
European Part ◽  
The Other ◽  
Michigan Basin ◽  
The North ◽  
Sharp Edges ◽  
North American Craton ◽  
Distinct Morphology

AbstractThe present study of the Eifelian icriodid conodonts is based on collections from Belarus and the Michigan Basin (USA). It is here proposed that forms originally included in Icriodus orri Klapper and Barrick, 1983 can be attributed to I. retrodepressus Bultynck, 1970, Icriodus orri sensu stricto, and Icriodus michiganus new species, each displaying a distinct morphology, stratigraphical range, and geographic distribution. Icriodus retrodepressus, characterized by a triangular spindle, deep depression in its posterior part, and a well-pronounced spur and antispur, appeared in the lower partitus Zone of the lowermost Eifelian and disappeared in the upper Eifelian kockelianus Zone. Icriodus michiganus n. sp., distinguished by a lachrymiform spindle with a shallow posterior depression, ranges from the lower costatus Zone to the upper kockelianus Zone. Icriodus orri differs from the other two species by the occurrence of transverse denticle rows with lateral denticles displaying sharp edges. It ranges from the upper kockelianus Zone to the ensensis Zone of the uppermost Eifelian. Icriodus retrodepressus first occurred in the European part of the Euramerican continent and later migrated into the North American area. Icriodus michiganus n. sp. has been found in the interior part of the North American Craton and near the eastern Euramerican margin. Icriodus orri occurs in the North American interior, in British Columbia (Canada), and in the eastern part of Euramerica (Belarus). The introduction of I. retrodepressus can be related to the transgressive Choteč Event, whereas that of I. orri to a transgressive stage of the Ie eustatic cycle.

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