scholarly journals Shadow Map Construction using 2D Homography

2020 ◽  
Vol 9 (4) ◽  
pp. 2485-2488
Keyword(s):  
Computer Graphic ◽  
Map Construction ◽  
Shadow Map ◽  
Shadow Maps ◽  
The Relationship ◽  
Homography Transformation

In computer graphic applications, shadow plays an important role in expressing the reality of an object. Shadow shows the relationship between objects in space. Shadow map is one of the methods that meet the demand simplification in implementation and speed. This method made an alias around the border of shading. In this paper, we proposed a method using a 2D homography transformation. This method reduces the unused area in the shadow maps, so it can help to minimize the alias. With the experiment in VanMieu Tran Bien- a Vietnamese historical place, we compare the method with others.

scholarly journals The virtual journey through history: from projects to building phases of one of the most famous baroque Royal Palace in the UNESCO’s World Heritage List

2015 ◽  
Vol 4 (8) ◽  
pp. 109
Author(s):  
Elena Biondi ◽  
Alessandro Bovero
Keyword(s):  
Seventeenth Century ◽  
Computer Graphic ◽  
Three Dimensional ◽  
3D Reconstructions ◽  
Virtual Camera ◽  
World Heritage List ◽  
Town Centre ◽  
Graphic Modeling ◽  
History Of ◽  
The Relationship

<p>In this paper we present an experience designed to introduce virtual reality and computer graphic modeling as representing tools in all phases of interpretation, analysis, reconstruction and communication of archaeological and historical researches on Venaria Reale Complex. Ten three-dimensional CG reconstructions represent exterior shapes of the Complex corresponding its five major building phases: the relationship between the old town centre, the Royal Complex and its Gardens has been consistently the result of an unified vision. The virtual pass into the history of that site since seventeenth century to the present has been realized with careful virtual camera flight through 3D reconstructions. The main purpose for the final video was to highlight the most significant elements that mark urban and architectural evolutions.</p>

scholarly journals Towards Cross-View Consistency in Semantic Segmentation While Varying View Direction

2021 ◽  
Author(s):  
Xin Tong ◽  
Xianghua Ying ◽  
Yongjie Shi ◽  
He Zhao ◽  
Ruibin Wang
Keyword(s):  
Receptive Field ◽  
Semantic Segmentation ◽  
The Other ◽  
Multiple View Geometry ◽  
Multiple View ◽  
Segmentation Methods ◽  
Learning Dynamic ◽  
Relationship Of ◽  
The Relationship ◽  
Homography Transformation

Several images are taken for the same scene with many view directions. Given a pixel in any one image of them, its correspondences may appear in the other images. However, by using existing semantic segmentation methods, we find that the pixel and its correspondences do not always have the same inferred label as expected. Fortunately, from the knowledge of multiple view geometry, if we keep the position of a camera unchanged, and only vary its orientation, there is a homography transformation to describe the relationship of corresponding pixels in such images. Based on this fact, we propose to generate images which are the same as real images of the scene taken in certain novel view directions for training and evaluation. We also introduce gradient guided deformable convolution to alleviate the inconsistency, by learning dynamic proper receptive field from feature gradients. Furthermore, a novel consistency loss is presented to enforce feature consistency. Compared with previous approaches, the proposed method gets significant improvement in both cross-view consistency and semantic segmentation performance on images with abundant view directions, while keeping comparable or better performance on the existing datasets.

HARDWARE-ACCELERATED PARALLEL-SPLIT SHADOW MAPS

2008 ◽  
Vol 08 (02) ◽  
pp. 223-241 ◽  
Author(s):  
FAN ZHANG ◽  
HANQIU SUN ◽  
LEILEI XU ◽  
KITLUN LEE
Keyword(s):  
Real Time ◽  
Large Scale ◽  
Depth Range ◽  
High Quality ◽  
Shadow Mapping ◽  
Complex Scenes ◽  
Shadow Map ◽  
Shadow Maps

Shadow mapping is well known for its generality and efficiency, thus it has been extensively employed for real-time shadow rendering in diverse applications. However, it suffers from inherent aliasing problem due to its image-based nature. In this paper, we present the parallel-split shadow maps scheme which produces high-quality shadows especially in large-scale and complex scenes. Our scheme splits the view frustum into parts using planes parallel to the view plane, and then generates a shadow map for each part. A fast and robust splitting strategy based on the analysis of shadow-map aliasing is proposed, which results in a moderate aliasing distribution over the depth range. Hardware-accelerated processing is developed to eliminate extra rendering passes which surpass that of standard shadow mapping when synthesizing scene-shadows.

Shadow map filtering with Gaussian shadow maps

2011 ◽  
Author(s):  
Jesús Gumbau ◽  
Mateu Sbert ◽  
László Szirmay-Kalos ◽  
Miguel Chover ◽  
Carlos González
Keyword(s):  
Shadow Map ◽  
Shadow Maps

scholarly journals Interactive 3D Time-Integrated Solar Shadow Maps

2019 ◽  
Vol 1 ◽  
pp. 1-2
Author(s):  
Georg Molzer ◽  
Florian Ledermann
Keyword(s):  
Urban Areas ◽  
Distinct Point ◽  
Geographic Location ◽  
The Sun ◽  
Specific Point ◽  
Professional Activities ◽  
Shadow Map ◽  
Shadow Maps ◽  
Interactive 3D ◽  
Favorable Light

<p><strong>Abstract.</strong> Urban areas are characterized by a complex topography of buildings, terrain, vegetation and temporary structures, which, depending on their extent, geometry, geographic location and daytime, cast shadow on their surroundings. Given the importance of sunlight for various groups of interest and tasks, we argue that a comprehensive, accessible, usable and intuitive way of predicting its availability for specific usage contexts is surprisingly lacking. In our research, we are investigating how to improve the visual communication of urban solar conditions for various real-world usage scenarios like having a coffee in the sun, parking a car in the shade, or taking a photograph of a particular building in a favorable light. All of these activities take place over a period of time, not in a temporal instant, causing solar shadows to move. Hence, a static representation of the light situation at a distinct point in time, such as offered by available 3D urban maps or GIS systems, is often not sufficient for planning above mentioned recreational or professional activities.</p><p>This factor is incorporated in our system by integrating shadow motion into a shadow map that covers arbitrary timeframes within a given day (Figure 1). Shadows are accumulated by projecting shadow maps from astronomically precise sun positions spanning over the defined timeframe. The number of sampling points directly influences the quality and speed of the rendering. All provided figures currently sample and integrate nine different sun positions.</p><p>Using our system, questions in a manner of “Given a specific point in space, at which time will this point be in sun/shade again” can be answered. E.g., one would like to spend time in the sun at a specific Viennese “Kaffeehaus” (coffee place), from which time on (and for how long) will this space be sunlit (Figure 2). In the future, this process might even be automated.</p>

Interstellar gas in the central region of the Galaxy

1967 ◽  
Vol 31 ◽  
pp. 239-251 ◽  
Author(s):  
F. J. Kerr
Keyword(s):  
Central Region ◽  
Galactic Plane ◽  
Neutral Hydrogen ◽  
Continuum Emission ◽  
Galactic Centre ◽  
Interstellar Gas ◽  
Hydrogen Recombination ◽  
The Galaxy ◽  
Centre Region ◽  
The Relationship

A review is given of information on the galactic-centre region obtained from recent observations of the 21-cm line from neutral hydrogen, the 18-cm group of OH lines, a hydrogen recombination line at 6 cm wavelength, and the continuum emission from ionized hydrogen.Both inward and outward motions are important in this region, in addition to rotation. Several types of observation indicate the presence of material in features inclined to the galactic plane. The relationship between the H and OH concentrations is not yet clear, but a rough picture of the central region can be proposed.

The relationship of the scleractinian corals to the rugose corals

Paleobiology ◽  
1980 ◽  
Vol 6 (02) ◽  
pp. 146-160 ◽  
Author(s):  
William A. Oliver
Keyword(s):  
Critical Points ◽  
Scleractinian Corals ◽  
Convincing Evidence ◽  
Early Triassic ◽  
Rugose Corals ◽  
History Of ◽  
The Subject ◽  
Relationship Of ◽  
The Relationship ◽  
Biologic Factors

The Mesozoic-Cenozoic coral Order Scleractinia has been suggested to have originated or evolved (1) by direct descent from the Paleozoic Order Rugosa or (2) by the development of a skeleton in members of one of the anemone groups that probably have existed throughout Phanerozoic time. In spite of much work on the subject, advocates of the direct descent hypothesis have failed to find convincing evidence of this relationship. Critical points are:(1) Rugosan septal insertion is serial; Scleractinian insertion is cyclic; no intermediate stages have been demonstrated. Apparent intermediates are Scleractinia having bilateral cyclic insertion or teratological Rugosa.(2) There is convincing evidence that the skeletons of many Rugosa were calcitic and none are known to be or to have been aragonitic. In contrast, the skeletons of all living Scleractinia are aragonitic and there is evidence that fossil Scleractinia were aragonitic also. The mineralogic difference is almost certainly due to intrinsic biologic factors.(3) No early Triassic corals of either group are known. This fact is not compelling (by itself) but is important in connection with points 1 and 2, because, given direct descent, both changes took place during this only stage in the history of the two groups in which there are no known corals.

Choosing a Markov blanket

2020 ◽  
Vol 43 ◽  
Author(s):  
Thomas Parr
Keyword(s):  
Markov Blanket ◽  
Target Article ◽  
The Relationship

Abstract This commentary focuses upon the relationship between two themes in the target article: the ways in which a Markov blanket may be defined and the role of precision and salience in mediating the interactions between what is internal and external to a system. These each rest upon the different perspectives we might take while “choosing” a Markov blanket.

Tinkering with cognitive gadgets: Cultural evolutionary psychology meets active inference

2019 ◽  
Vol 42 ◽  
Author(s):  
Paul Benjamin Badcock ◽  
Axel Constant ◽  
Maxwell James Désormeau Ramstead
Keyword(s):  
Evolutionary Psychology ◽  
Research Program ◽  
Active Inference ◽  
Innovative Research ◽  
Cognitive Faculties ◽  
Cultural Evolutionary ◽  
The Relationship

Abstract Cognitive Gadgets offers a new, convincing perspective on the origins of our distinctive cognitive faculties, coupled with a clear, innovative research program. Although we broadly endorse Heyes’ ideas, we raise some concerns about her characterisation of evolutionary psychology and the relationship between biology and culture, before discussing the potential fruits of examining cognitive gadgets through the lens of active inference.

Radiation Damage, Contrast and Statistics in High Resolution Biological Electron Microscopy

1970 ◽  
Vol 28 ◽  
pp. 260-261
Author(s):  
Robert M. Glaeser
Keyword(s):  
High Resolution ◽  
Particle Flux ◽  
Unit Area ◽  
Signal To Noise ◽  
Resolution Image ◽  
High Resolution Image ◽  
Pass Through ◽  
Counting Statistics ◽  
The Relationship ◽  
Picture Element

It is well known that a large flux of electrons must pass through a specimen in order to obtain a high resolution image while a smaller particle flux is satisfactory for a low resolution image. The minimum particle flux that is required depends upon the contrast in the image and the signal-to-noise (S/N) ratio at which the data are considered acceptable. For a given S/N associated with statistical fluxtuations, the relationship between contrast and “counting statistics” is s131_eqn1, where C = contrast; r2 is the area of a picture element corresponding to the resolution, r; N is the number of electrons incident per unit area of the specimen; f is the fraction of electrons that contribute to formation of the image, relative to the total number of electrons incident upon the object.

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