Search results for "3D model"

Addressing the Occlusion Problem in Augmented Reality Environments with Phantom Hollow Objects

2018

Occlusion handling is essential to provide a seamless integration of virtual and real objects in AR applications. Different approaches have been presented with a variety of technologies, environment conditions and methods. Among these methods, 3D model-based occlusion approaches have been extensively used. However, these solutions could be too time-consuming in certain situations, since they must render all the occlusion objects even though they are invisible. For this reason, we propose an inverse 3D model-based solution for handling occlusions, designed for those AR applications in which virtual objects are placed inside a real object with holes or windows. With this restriction, the occl…

Estimation of Location and Activation Time of Purkinje Myocardial Junctions from Sparse and Noisy Endocardial Electrical Samples

2017

The activation of the myocardial muscle is triggered by Purkinje-myocardial junctions (PMJs), which are the terminal sites of the specialised cardiac conduction system (CCS). Obtaining the location of the PMJs and other sources of endocardial ectopic activity would be desirable for building computer models of cardiac electrophysiology and planning ablation interventions. We present a method to estimate the location and activation times of endocardial electrical sources in a 3D model of the ventricles. The algorithm requires a set of discrete electrical samples on the endocardium, which can include errors in location and activation time. The estimated sources are properly placed with a locat…

Developing a framework for using structure-from-motion techniques for road distress applications

2020

On Urban road networks, road agencies need to quickly identify road pavement distresses in order to identify appropriate maintenance and rehabilitation strategies. This is integral as agencies are plagued with financial and time constraint issues. There have been several attempts over the last few years to identify new solutions and techniques to solve these issues. Several of these have shown merit and accuracy in identifying distresses. However, the techniques in many instances are not correlated to available distress identification standards. One of the considered techniques is the use of Structure-from-Motion, which tries to recreate 3D distress models for identification and analysis. T…

Using UAV Based 3D Modelling to Provide Smart Monitoring of Road Pavement Conditions

2020

Road pavements need adequate maintenance to ensure that their conditions are kept in a good state throughout their lifespans. For this to be possible, authorities need efficient and effective databases in place, which have up to date and relevant road condition information. However, obtaining this information can be very difficult and costly and for smart city applications, it is vital. Currently, many authorities make maintenance decisions by assuming road conditions, which leads to poor maintenance plans and strategies. This study explores a pathway to obtain key information on a roadway utilizing drone imagery to replicate the roadway as a 3D model. The study validates this by using stru…

Integration of 3D modelling with photogrammetry applied on historical images for cultural heritage

2023

The recovery of past architecture through 3D modelling is an important challenge today to the preservation of heritage. Decisive support for the interpretation of architecture can certainly come from historical images and old photographs that fix a portion of space at a specific time, keeping it unchanged over the years. This acquisition is decisive for studying architectures of the past that can be reinterpreted and analysed. Photos, in fact, capture the advance of time and the life of a building at a precise historical moment, becoming essential documents for the study and knowledge of heritage. An additional advantage is when these old images can be processed through Structure for Motion…

A new approach to Road Pavement Management Systems by exploiting Data Analytics, Image Analysis and Deep Learning

2021

PERFORMANCE EVALUATIONS OF 3D WEB-SERVICES AND OPEN-SOURCE SOFTWARE FOR DIGITAL MODELING OF ARCHAEOLOGICAL FINDS

2016

The Structure From Motion (SFM) algorithms derived from Computer Vision community make image-based techniques a competitive and user friendly approach to obtain 3D information of real objects. These algorithms have been implemented in many 3D web-services and open-source software to develop free instruments for the reconstruction of very detailed 3D digital models. Their use is becoming very common above all in archaeological studies but their potentiality for metric application has not been tested at all. The aim of the work is to investigate the quality and the accuracy of 3D models obtained through 3D web-services and SFM open-source software. Different tests have been performed using so…

SfM Techniques Applied in Bad Lighting and Reflection Conditions: The Case of a Museum Artwork

2019

In recent years, SfM techniques have been widely used especially in the field of Cultural Heritage. Some applications, however, remain undefined in cases where the boundary conditions are not suitable for the technique. Examples of this are instances where there are poor lighting conditions and the presence of glass and reflective surfaces. This paper presents a case study where SfM is applied, using a DSLR camera (Nikon D5200), to the “Head of Hades” inside a glass theca and under a large number of light sources at different distances and of different intensities and sizes. The geometric evaluation has been made comparing the DSLR camera model against the 3D data acquired with structured l…

3D Image Based Modelling Using Google Earth Imagery for 3D Landscape Modelling

2019

In recent years SfM technique experiments have been innumerable and increasingly refined under metric profiles. The techniques rely on photographic datasets of the objects or landscapes which can require in most cases time consuming and expensive surveys. Recently however there have been increases in the available 3D data of sites worldwide on the Google Earth (GE) platform. This paper presents a unique experimentation that considers integrating readily available datasets from GE and images taken during surveys on ground level for 3D replication without the use of expensive aerial surveys. This will enable practitioners the ability to more easily create 3D models of cultural heritage signif…

Survey and Photogrammetric Restitution of Monumental Complexes: Issues and Solutions—The Case of the Manfredonic Castle of Mussomeli

2019

The latest results obtained through photogrammetric restitution enhanced by GNSS (Global Navigation Satellite System) RTK (Real-Time Kinematic) survey achieved increased levels of accuracy. These survey solutions are used to rapidly obtain a detailed model with an excellent level of accuracy (centimetric) with cheaper equipment. However, the contour conditions are not always favorable for obtaining the best results in a simple way. The work presented in this paper shows the survey and the photogrammetric restitution of the Manfredonic Castle of Mussomeli in Sicily, developed as a part of the PON NEPTIS European Project, aimed at the valorization of Cultural Heritage (CH). This case is a typ…