Projective Geometry for 3D Modeling of Objects

2012 ◽  
pp. 28-48
Author(s):  
Rimon Elias
Keyword(s):  
Computer Vision ◽  
Projective Geometry ◽  
3D Modeling ◽  
Multiple Images ◽  
Single View ◽  
3D Space ◽  
Camera Parameters ◽  
Geometrical Relationships

This chapter surveys many fundamental aspects of projective geometry that have been used extensively in computer vision literature. In particular, it discusses the role of this branch of geometry in reconstructing basic entities (e.g., 3D points, 3D lines, and planes) in 3D space from multiple images. The chapter presents the notation of different elements. It investigates the geometrical relationships when one or two cameras are observing the scene creating single-view and two-view geometry. In other words, camera parameters in terms of locations and orientations, with respect to 3D space and with respect to other cameras, create relationships. This chapter discusses these relationships and expresses them mathematically. Finally, different approaches to deal with the existence of noise or inaccuracy in general are presented.

Projective Geometry for 3D Modeling of Objects

2013 ◽  
pp. 125-144
Author(s):  
Rimon Elias
Keyword(s):  
Computer Vision ◽  
Projective Geometry ◽  
3D Modeling ◽  
Multiple Images ◽  
Single View ◽  
3D Space ◽  
Camera Parameters ◽  
Geometrical Relationships

This chapter surveys many fundamental aspects of projective geometry that have been used extensively in computer vision literature. In particular, it discusses the role of this branch of geometry in reconstructing basic entities (e.g., 3D points, 3D lines, and planes) in 3D space from multiple images. The chapter presents the notation of different elements. It investigates the geometrical relationships when one or two cameras are observing the scene creating single-view and two-view geometry. In other words, camera parameters in terms of locations and orientations, with respect to 3D space and with respect to other cameras, create relationships. This chapter discusses these relationships and expresses them mathematically. Finally, different approaches to deal with the existence of noise or inaccuracy in general are presented.

Image Based 3D Modeling and Rendering from Single View Perspective Images

2013 ◽  
pp. 604-620
Author(s):  
S. Mohan ◽  
S. Murali
Keyword(s):  
Computer Vision ◽  
3D Modeling ◽  
Real World ◽  
3D Models ◽  
Edge Length ◽  
Geometric Information ◽  
Single View ◽  
Perspective Image ◽  
Cad Cam ◽  
Cam Software

In computer vision, 3D modeling refers to the process of developing 3D representation of the real world objects with systematic procedure. The 3D models can be built based on geometric information about the object or scene to be modeled using CAD/CAM software. However, this approach needs prior knowledge of the objects in the scene like dimension, size of objects, distance from the object to camera, et cetera. To make the 3D models more photo realistic and convenient, images of the objects can be used to build the 3D models. In this chapter, the authors propose a method to extract 3D model from single view perspective image. The approach is based on edge length and exploiting symmetric objects in the scene. Later, an application of touring into picture is discussed with the proposed method.

Image Based 3D Modeling and Rendering from Single View Perspective Images

2012 ◽  
pp. 197-214
Author(s):  
S. Mohan ◽  
S. Murali
Keyword(s):  
Computer Vision ◽  
3D Modeling ◽  
Real World ◽  
3D Models ◽  
Edge Length ◽  
Geometric Information ◽  
Single View ◽  
Perspective Image ◽  
Cad Cam ◽  
Cam Software

In computer vision, 3D modeling refers to the process of developing 3D representation of the real world objects with systematic procedure. The 3D models can be built based on geometric information about the object or scene to be modeled using CAD/CAM software. However, this approach needs prior knowledge of the objects in the scene like dimension, size of objects, distance from the object to camera, et cetera. To make the 3D models more photo realistic and convenient, images of the objects can be used to build the 3D models. In this chapter, the authors propose a method to extract 3D model from single view perspective image. The approach is based on edge length and exploiting symmetric objects in the scene. Later, an application of touring into picture is discussed with the proposed method.

scholarly journals The Potential of Computer Vision-Based Marker-Less Human Motion Analysis for Rehabilitation

2021 ◽  
Vol 10 ◽  
pp. 117957272110223
Author(s):  
Thomas Hellsten ◽  
Jonny Karlsson ◽  
Muhammed Shamsuzzaman ◽  
Göran Pulkkis
Keyword(s):  
Computer Vision ◽  
Motion Analysis ◽  
Pose Estimation ◽  
Joint Angle ◽  
Human Motion ◽  
Human Pose Estimation ◽  
Human Motion Analysis ◽  
Single View ◽  
Recent Computer ◽  
Human Pose

Background: Several factors, including the aging population and the recent corona pandemic, have increased the need for cost effective, easy-to-use and reliable telerehabilitation services. Computer vision-based marker-less human pose estimation is a promising variant of telerehabilitation and is currently an intensive research topic. It has attracted significant interest for detailed motion analysis, as it does not need arrangement of external fiducials while capturing motion data from images. This is promising for rehabilitation applications, as they enable analysis and supervision of clients’ exercises and reduce clients’ need for visiting physiotherapists in person. However, development of a marker-less motion analysis system with precise accuracy for joint identification, joint angle measurements and advanced motion analysis is an open challenge. Objectives: The main objective of this paper is to provide a critical overview of recent computer vision-based marker-less human pose estimation systems and their applicability for rehabilitation application. An overview of some existing marker-less rehabilitation applications is also provided. Methods: This paper presents a critical review of recent computer vision-based marker-less human pose estimation systems with focus on their provided joint localization accuracy in comparison to physiotherapy requirements and ease of use. The accuracy, in terms of the capability to measure the knee angle, is analysed using simulation. Results: Current pose estimation systems use 2D, 3D, multiple and single view-based techniques. The most promising techniques from a physiotherapy point of view are 3D marker-less pose estimation based on a single view as these can perform advanced motion analysis of the human body while only requiring a single camera and a computing device. Preliminary simulations reveal that some proposed systems already provide a sufficient accuracy for 2D joint angle estimations. Conclusions: Even though test results of different applications for some proposed techniques are promising, more rigour testing is required for validating their accuracy before they can be widely adopted in advanced rehabilitation applications.

A Digital Diagnostic Aide for Skincare: The Role of Computer Vision and Machine Learning in Revealing Skin Texture Changes

2020 ◽  
pp. 898-915
Author(s):  
Jaya Shankar Vuppalapati ◽  
Santosh Kedari ◽  
Anitha Ilapakurti ◽  
Chandrasekar Vuppalapati ◽  
Sharat Kedari ◽  
...  
Keyword(s):  
Machine Learning ◽  
Computer Vision ◽  
Skin Texture

scholarly journals THIOZOLIDINEDIONES IN THE TREATMENT OF PATIENTS WITH EXTENSIVE PSORIASIS AND CONCOMITANT ALIMENTARY OBESITY

2020 ◽  
Vol 20 (4) ◽  
pp. 30-34
Author(s):  
Ya.O. Yemchenko ◽  
K.Ye. Ishcheikin ◽  
I.P. Kaidashev
Keyword(s):  
Systemic Inflammation ◽  
Molecular Mechanisms ◽  
Current Data ◽  
The Body ◽  
Internal Organs ◽  
Single View ◽  
Multifactorial Diseases ◽  
Alimentary Obesity ◽  
Inflammatory Processes

Psoriasis is one of the most common chronic recurrent systemic autoimmune multifactorial diseases, affected the skin, joints, internal organs and systems of the body. Despite the significant prevalence of psoriasis and a large number of studies devoted this problem there is still no single view on the pathogenesis of this dermatosis. To clear up the pathogenesis of psoriasis, it seems to be reasonable to focus on the common comorbidities or multimorbidities, which may occur in the course of psoriasis, as this issue is still insufficiently studied. Recent reports have proven the evidences of indisputable link between psoriasis and obesity. The scientific literature extensively covers the issues of identical pathogenetic mechanisms of inflammatory processes in psoriasis and obesity. Given the current data on the role of systemic inflammation underlying the development of both psoriasis and obesity, the study of molecular mechanisms of its development and in particularly the role of proinflammatory nuclear transcription factors, thiazolidinediones have been found out as pathogenetically justified medicine of choice for the therapy of these diseases. In this study, we determined the effectiveness of using 30 mg of pioglitazone daily for 6 months in the course of treatment for patients with extensive psoriasis vulgaris of moderate severity, who were also diagnosed as having concomitant grade І-ІІ alimentary obesity that was supported by clinical and immunological findings evidenced of systemic inflammation. Analyzing the results obtained, we have found out the prolonged therapy with pioglitazone leads to a decrease in systemic inflammation and contributes to a milder recurrent course of psoriasis.

scholarly journals infância, cultura visual e educação

2020 ◽  
Vol 16 (36) ◽  
pp. 01-20
Author(s):  
Adriana Hoffmann Fernandes ◽  
Helenice Mirabelli Cassino
Keyword(s):  
Elementary School ◽  
Visual Culture ◽  
Philosophical Approach ◽  
Multiple Images ◽  
The World ◽  
Visual Framing ◽  
The Media ◽  
The Relationship ◽  
The Way

This article combines thoughts about childhood, visual culture and education. It is known that we live among multiple images that shape the way we see our reality, and researchers in the visual culture field investigate how this role is played out in our culture. The goal is to make some applications those ideas, to think about the relationship between the images and education. This article tries to grasp what visual culture is and in what ways presumptions about childhood generate and are generated by this association. It also discusses the genesis of these presumptions and the images they generate through a philosophical approach, questioning the role of education in a culture tied to the media, and about how children, who are familiar with multiple screens, presage a new visual literacy. We see how images play a fundamental role in the way children give meaning to the world around them and to themselves, in the context of their local culture. Given this context, it is necessary to consider how visual culture is tied to the elementary school, and what challenges confront the generation of wider and more creative ways to approach visual framing in children’s education.

scholarly journals Bringing the German Pavilion Back Home

2021 ◽  
Author(s):  
◽  
Jessica Wright
Keyword(s):  
Projective Geometry ◽  
Principal Part ◽  
Linear Perspective ◽  
Two Dimensional ◽  
Dimensional Representation ◽  
New Form

<p>This research investigates a correspondence between the architectural representational tool of drawing, and the translations of these into something recognised as ‘built’. It is fundamentally concerned around representation in architecture driven by the principles that our entire engagement with architecture is via representation. Architects do not produce buildings but produce images of buildings, and the role of two-dimensional representation plays a principal part in architecture. Architecture is always representational, and the more we engage with representation the more we might push the envelope with what we understand architecture to be.   This thesis aims to establish within the contemporary discipline, what we understand about the responsibility of linear perspective as a representational tool. By understanding what lies behind the canon of perspective in architecture, this thesis questions whether the representation of conventional architecture could benefit from a new way of drawing linear perspective?   The discovery of perspective during the Renaissance has influenced not only our way of representing architecture but also how we view, and therefore design it. It has become integrated with our understanding of architecture at an unconscious level. Architects no longer need control of projective geometry, and due to this cannot be critical of the system of representation or control its limits. This leads to mediate a shift in perspective, with the intention to generate a representation of new form.   The motivation for this thesis was that from linear perspective, as it has done so for centuries, we can produce evocative and meaningful vocabularies that attempt to enrich architecture.</p>

Hybrid Image Segmentation Within a Computer Vision Hierarchy

1993 ◽  
Vol 30 (1) ◽  
pp. 51-64
Author(s):  
Ray Thomas ◽  
Fariborz Zahedi
Keyword(s):  
Computer Vision ◽  
Image Segmentation ◽  
Vision System ◽  
Critical Role ◽  
Generic Model ◽  
Test Results ◽  
Segmentation Approach ◽  
Edge Based

Hybrid image segmentation within a computer vision hierarchy A generic model of a computer vision system is presented which highlights the critical role of image segmentation. A hybrid segmentation approach, utilising both edge-based and region-based techniques, is proposed for improved quality of segmentation. An image segmentation architecture is outlined and test results are presented and discussed.

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