scholarly journals Evaluation of visual cues of three-dimensional virtual environments for helicopter simulators

2011 ◽  
Vol 9 (4) ◽  
pp. 347-360
Author(s):  
Yasemin Çetin ◽  
Erdal Yılmaz ◽  
Yasemin Yardımcı Çetin
Keyword(s):  
Visual Cues ◽  
Three Dimensional ◽  
Distance Estimation ◽  
3D Object ◽  
3D Objects ◽  
Helicopter Flight ◽  
Flight Simulators ◽  
Computer Based ◽  
Low Altitude ◽  
Military Pilots

Visual cues are an essential part of helicopter flight simulators. The required cues for hover are particularly large, due to closeness to the ground and small movements. However, the research on low-altitude helicopter flight is limited. In this research, the density and height of the three-dimensional (3D) objects in the scene are analysed to find their effect on hovering and low-altitude helicopter flight. An experiment is conducted using a personal computer-based flight simulator on 10 professional military pilots. The results revealed that 3D object density and 3D object height affect both horizontal and vertical hovering performance. In hover and low-altitude flight, altitude control is positively affected by smaller object height. Paradoxically, the pilots preferred the scenes composed of tall and mixture objects. Pilot distance estimation was significantly affected by the knowledge of both object density and object height, but these factors do not individually improve distance estimation.

V4 lesions in macaques affect both single- and multiple-viewpoint shape discriminations

1998 ◽  
Vol 15 (2) ◽  
pp. 359-367 ◽  
Author(s):  
WILLIAM H. MERIGAN ◽  
HONG AN PHAM
Keyword(s):  
Visual Field ◽  
Visual Cues ◽  
Three Dimensional ◽  
Right Visual Field ◽  
Shape Discrimination ◽  
Area V4 ◽  
3D Objects ◽  
Contrast Thresholds ◽  
Object Similarity ◽  
Visual Shape

The role of cortical area V4 in complex shape discriminations was studied by testing the effects of V4 lesions in macaques on the ability to visually discriminate between images of three-dimensional (3D) objects from different viewpoints. Stimuli were presented in pairs in the lower left or lower right visual field quadrants about 4 deg from the fovea, and the monkeys judged on each trial whether the two views were of the same or of different objects. Object similarity was varied to determine a threshold shape difference. V4 lesions caused profound, retinotopic, and apparently permanent disruptions of discrimination, regardless of whether the images represented single or multiple viewpoints. In V4 lesioned portions of the visual field, monkeys could discriminate objects only when they differed much more grossly in shape than was true in control locations. These effects of the lesion were virtually identical for discriminations that had been learned before lesions were placed and for those learned afterwards. As in previous studies, V4 lesions elevated contrast thresholds by approximately a factor of two, but control observations showed that this was not the basis of the disruption of shape discrimination. Manipulation of cues to shape showed that in control locations, monkeys maintained excellent shape discrimination despite a variety of stimulus alterations, whereas in V4 lesioned areas their performance was easily disrupted. This finding suggests that V4 may support visual shape discriminations by facilitating the use of multiple visual cues. However, the fact that single-viewpoint and multiple-viewpoint discriminations were similarly affected indicates that the disruption was not specific to 3D shape discrimination, but may apply to a variety of subtle discriminations.

scholarly journals Rapid and Blind Watermarking Approach of the 3D Objects Using QR Code Images for Securing Copyright

2021 ◽  
Vol 2021 ◽  
pp. 1-11
Author(s):  
Hanan S. Al-Saadi ◽  
Ahmed Elhadad ◽  
A. Ghareeb
Keyword(s):  
Digital Media ◽  
Three Dimensional ◽  
Extraction Process ◽  
Manhattan Distance ◽  
Human Observer ◽  
Qr Code ◽  
3D Object ◽  
3D Objects ◽  
Wide Range ◽  
Code Image

Watermarking techniques in a wide range of digital media was utilized as a host cover to hide or embed a piece of information message in such a way that it is invisible to a human observer. This study aims to develop an enhanced rapid and blind method for producing a watermarked 3D object using QR code images with high imperceptibility and transparency. The proposed method is based on the spatial domain, and it starts with converting the 3D object triangles from the three-dimensional Cartesian coordinate system to the two-dimensional coordinates domain using the corresponding transformation matrix. Then, it applies a direct modification on the third vertex point of each triangle. Each triangle’s coordinates in the 3D object can be used to embed one pixel from the QR code image. In the extraction process, the QR code pixels can be successfully extracted without the need for the original image. The imperceptibly and the transparency performances of the proposed watermarking algorithm were evaluated using Euclidean distance, Manhattan distance, cosine distance, and the correlation distance values. The proposed method was tested under various filtering attacks, such as rotation, scaling, and translation. The proposed watermarking method improved the robustness and visibility of extracting the QR code image. The results reveal that the proposed watermarking method yields watermarked 3D objects with excellent execution time, imperceptibility, and robustness to common filtering attacks.

Method for Generating 3D-Viewing Window for Web-Based E-Catalog

2004 ◽  
Author(s):  
Deuk-Hee Lee ◽  
Sehyung Park ◽  
Sungdo Ha ◽  
Yunyeong Lee
Keyword(s):  
New Products ◽  
Three Dimensional ◽  
3D Models ◽  
Web Based ◽  
Template Model ◽  
3D Object ◽  
3D Objects ◽  
Electronic Catalogs ◽  
Cad Models ◽  
The Way

This paper presents a framework-based procedure to generate three-dimensional electronic catalogs (3d e-catalogs), which link three-dimensional viewing windows (3d viewing windows) to e-catalogs. The 3d viewing windows include the three-dimensional interactive and event-driven objects (3d objects) of products for e-catalogs; the 3d viewing windows view and manipulate the 3d objects. The framework provides users with the template models of 3d viewing windows and 3d objects; the template model of a 3d viewing window is defined in HTML and the template model of a 3d object is defined in VRML. Users will specify the components of the template models, and complete the 3d viewing windows including the 3d objects of the new products to be displayed in 3d e-catalogs. In addition, the framework presents the way to get hierarchical 3d models from CAD models of products.

THREE-DIMENSIONAL OBJECT RECOGNITION USING AN ORTHOGONAL COMPLEX AR MODEL APPROACH

2000 ◽  
Vol 14 (02) ◽  
pp. 93-112
Author(s):  
F. W. TO ◽  
K. M. TSANG
Keyword(s):  
Object Recognition ◽  
Effective Means ◽  
Three Dimensional ◽  
Fixed Number ◽  
Ar Model ◽  
Model Parameters ◽  
3D Object ◽  
3D Objects ◽  
Stable Orientation ◽  
Dimensional Object

The analysis and recognition of 2D shapes using the orthogonal complex AR model has been extended for the recognition of arbitrary 3D objects. A 3D object is placed at one of its stable orientation and sectioned into a fixed number of "slices" of equal thickness in such a way that the "slices" are parallel to the object's stable plane. The surface of an object can be represented by a sequence of these parallel 2D closed contours. A complex AR model is then fitted to each of these contours. An orthogonal estimator is implemented to determine the correct model order and to estimate the associated model parameters. The estimated AR model parameters, magnitude ratios and the relative centroid associated with each 2D contour are used as essential features for 3D object recognition. An algorithm with hierarchical structure for the recognition of 3D objects is derived based on matching the sequence of 2D contours. Simulation studies are included to show the effectiveness of different criteria being applied at different stages of the recognition process. Test results have shown that the proposed approach can provide a feasible and effective means for recognizing arbitrary 3D objects which can be self-occluded and have a number of stable orientation.

scholarly journals EXPLORING THE EFFICACY AND EFFECTIVENESS OF REMINISCENCE USING THREE-DIMENSIONAL PRINTED OBJECTS

2019 ◽  
Vol 3 (Supplement_1) ◽  
pp. S308-S308
Author(s):  
Keith A Anderson ◽  
Marla Berg-Weger ◽  
Tom Plocher ◽  
Anne Farina ◽  
Joseph E Gaugler
Keyword(s):  
Quality Of Life ◽  
Older Adults ◽  
Phase I ◽  
Phase Ii ◽  
Social Engagement ◽  
Three Dimensional ◽  
3D Object ◽  
3D Objects ◽  
Centered Care

Abstract Reminiscence therapy (RT) is a form of person-centered care that involves the exploration of past activities, events, and experiences with another person or in a small group. Research on RT has found an array of benefits for older adults, including improvements in mood, quality of life, social interaction, cognition, and memory. In this presentation, the researchers report on Phases I and II of an evaluation of a reminiscence using three-dimensional (3D) printed objects from older adults’ pasts. Advances in 3D printing technology now allow researchers to create scale replicas of cherished items from peoples’ pasts, such as toys, bicycles, pets, automobiles, boats, and houses. In Phase I, the researchers evaluated the efficacy of incorporating 3D objects in reminiscence using a parallel convergent mixed methods design. Participants agreed or strongly agreed that the 3D object reminiscence was well-received (88.9%), facilitated reminiscence (83.3%), increased engagement and alertness (72.3%). Qualitative data identified additional benefits of the use of 3D objects in reminiscence, including increases in social engagement and interactions with staff and family members. In Phase II, the researchers are evaluating the effectiveness of a formal 3D reminiscence intervention using a randomized control trial of 175 older adults. The researchers hypothesize that 3D object reminiscence will be more effective than reminiscence using verbal cues in stimulating memory and enhancing cognition, engagement, mood, and quality of life. Preliminary findings from Phase II will be reported along with the findings from Phase I.

scholarly journals Monocular 3D Object Detection Based on Uncertainty Prediction of Keypoints

Machines ◽  
2021 ◽  
Vol 10 (1) ◽  
pp. 19
Author(s):  
Mu Chen ◽  
Huaici Zhao ◽  
Pengfei Liu
Keyword(s):  
Object Detection ◽  
Three Dimensional ◽  
Monocular Vision ◽  
Geometric Constraints ◽  
Object Position ◽  
3D Object ◽  
Uncertainty Prediction ◽  
3D Objects ◽  
Prediction Module ◽  
3D Object Detection

Three-dimensional (3D) object detection is an important task in the field of machine vision, in which the detection of 3D objects using monocular vision is even more challenging. We observe that most of the existing monocular methods focus on the design of the feature extraction framework or embedded geometric constraints, but ignore the possible errors in the intermediate process of the detection pipeline. These errors may be further amplified in the subsequent processes. After exploring the existing detection framework of keypoints, we find that the accuracy of keypoints prediction will seriously affect the solution of 3D object position. Therefore, we propose a novel keypoints uncertainty prediction network (KUP-Net) for monocular 3D object detection. In this work, we design an uncertainty prediction module to characterize the uncertainty that exists in keypoint prediction. Then, the uncertainty is used for joint optimization with object position. In addition, we adopt position-encoding to assist the uncertainty prediction, and use a timing coefficient to optimize the learning process. The experiments on our detector are conducted on the KITTI benchmark. For the two levels of easy and moderate, we achieve accuracy of 17.26 and 11.78 in AP3D, and achieve accuracy of 23.59 and 16.63 in APBEV, which are higher than the latest method KM3D.

2D vs. 3D Visual Cues for Altitude Maintenance in Low-Altitude Flight

2007 ◽  
Vol 51 (19) ◽  
pp. 1287-1290
Author(s):  
Rob Gray
Keyword(s):  
Visual Cues ◽  
Motion Parallax ◽  
Visual Scene ◽  
Relative Importance ◽  
Object Position ◽  
Low Level ◽  
3D Objects ◽  
Level Flight ◽  
Low Altitude ◽  
2D And 3D

Previous research on altitude maintenance in low-altitude flight has focused either on cues provided by 2D features in the visual scene (e.g., splay angle) or on visual cues provided by the presence of 3D objects in the scene (e.g., occlusion). Therefore, little is known about the relative importance of 2D and 3D cues in altitude maintenance. We systematically varied the position variability, height, and pattern of surface elements in a simulated low-level flight environment to vary the salience of 2D and 3D visual cues. For 2D objects, altitude variability increased as a function of object position variability indicating that splay and depression angles are not reliable cues for terrains with irregularly spaced objects. For 3D objects, altitude variability increased less (or not at all) as a function of position variability indicating that the cues provided by 3D objects such as occlusion and motion parallax are the dominant visual cues for altitude maintenance for natural terrains with irregularly spaced objects.

scholarly journals A Semi-Automatic Reconstruction of Archaeological Pottery Fragments from 2D Images Using Wavelet Transformation

Heritage ◽  
2021 ◽  
Vol 4 (1) ◽  
pp. 76-90
Author(s):  
Dariush Eslami ◽  
Luca Di Angelo ◽  
Paolo Di Stefano ◽  
Emanuele Guardiani
Keyword(s):  
Wavelet Transformation ◽  
State Of The Art ◽  
Three Dimensional ◽  
Correlation Coefficients ◽  
Transformation Method ◽  
3D Objects ◽  
Archaeological Pottery ◽  
Computer Based ◽  
Approximation Coefficients ◽  
2D Images

The problem of matching fragments of three-dimensional (3D) objects has gained increasing attention, and several approaches have been developed to solve this problem. To date, however, to the best knowledge of the authors, there is no computer-based method supporting archaeologists in this activity. For this purpose, in this paper, a semi-automatic approach is proposed for the reconstruction of archaeological pottery fragments based on two-dimensional (2D) images. Firstly, the method, considering the curves as features, involves the extraction of edge curves by applying the Canny filter algorithm to the fragments’ image. Next, the wavelet transformation method is used to fit the edge curves and obtain the approximation coefficients. Then, the correlation coefficients between fragments are computed and the matching of fragments is done by comparing their values. The proposed approach is tested on some real cases. The results of the experimentation show, if compared with the state-of-the-art, that the method seems to be efficient and accurate in the reconstruction of pottery from 2D images of their fragments.

scholarly journals A computer-based approach for developing linamarase inhibitory agents

2020 ◽  
Vol 5 (7) ◽  
Author(s):  
Lucas Paul ◽  
Celestin N. Mudogo ◽  
Kelvin M. Mtei ◽  
Revocatus L. Machunda ◽  
Fidele Ntie-Kang
Keyword(s):  
Structure Elucidation ◽  
Three Dimensional ◽  
Data Bank ◽  
Competitive Inhibitor ◽  
Industrial Applications ◽  
Dimensional Structure ◽  
Full Understanding ◽  
The Poor ◽  
Computer Based ◽  
Inhibitory Agents

AbstractCassava is a strategic crop, especially for developing countries. However, the presence of cyanogenic compounds in cassava products limits the proper nutrients utilization. Due to the poor availability of structure discovery and elucidation in the Protein Data Bank is limiting the full understanding of the enzyme, how to inhibit it and applications in different fields. There is a need to solve the three-dimensional structure (3-D) of linamarase from cassava. The structural elucidation will allow the development of a competitive inhibitor and various industrial applications of the enzyme. The goal of this review is to summarize and present the available 3-D modeling structure of linamarase enzyme using different computational strategies. This approach could help in determining the structure of linamarase and later guide the structure elucidation in silico and experimentally.

ELEMENT-FREE METHODS VS. MESH-LESS CAE

2006 ◽  
Vol 03 (04) ◽  
pp. 445-464 ◽  
Author(s):  
HIDEYUKI SAKURAI
Keyword(s):  
Mesh Generation ◽  
Flow Analysis ◽  
Three Dimensional ◽  
Generation Task ◽  
3D Objects ◽  
Computer Aided ◽  
Analysis System ◽  
Mesh Less ◽  
Element Free ◽  
Cae System

Element-free methods (EFreeMs) are expected to eliminate the mesh generation task. However, a computer aided engineering (CAE) system by EFreeM for complex three-dimensional (3D) objects has not yet been developed. This paper discusses the obstacles to the CAE and way to solve them. A 3D groundwater flow analysis system with an EFreeM is presented as a practical CAE. In the system, instead of pursuing mesh-less CAE, a unique mesh is employed to achieve the practical CAE. Some 3D examples show the performance and usefulness of the system. Two serious drawbacks of the EFreeM are also discussed from the viewpoint of the practical CAE.

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