scholarly journals Evaluating Feature Extraction Methods with Synthetic Noise Patterns for Image-Based Modelling of Texture-Less Objects

2020 ◽  
Vol 12 (23) ◽  
pp. 3886
Author(s):  
Jahanzeb Hafeez ◽  
Jaehyun Lee ◽  
Soonchul Kwon ◽  
Sungjae Ha ◽  
Gitaek Hur ◽  
...  
Keyword(s):  
Feature Extraction ◽  
3D Reconstruction ◽  
Feature Matching ◽  
Low Cost ◽  
Three Dimensional ◽  
Extraction Methods ◽  
Planar Surfaces ◽  
Vision Sensors ◽  
3D Printed ◽  
3D Information

Image-based three-dimensional (3D) reconstruction is a process of extracting 3D information from an object or entire scene while using low-cost vision sensors. A structure-from-motion coupled with multi-view stereo (SFM-MVS) pipeline is a widely used technique that allows 3D reconstruction from a collection of unordered images. The SFM-MVS pipeline typically comprises different processing steps, including feature extraction and feature matching, which provide the basis for automatic 3D reconstruction. However, surfaces with poor visual texture (repetitive, monotone, etc.) challenge the feature extraction and matching stage and affect the quality of reconstruction. The projection of image patterns while using a video projector during the image acquisition process is a well-known technique that has been shown to be successful for such surfaces. In this study, we evaluate the performance of different feature extraction methods on texture-less surfaces with the application of synthetically generated noise patterns (images). Seven state-of-the-art feature extraction methods (HARRIS, Shi-Tomasi, MSER, SIFT, SURF, KAZE, and BRISK) are evaluated on problematic surfaces in two experimental phases. In the first phase, the 3D reconstruction of real and virtual planar surfaces evaluates image patterns while using all feature extraction methods, where the patterns with uniform histograms have the most suitable morphological features. The best performing pattern from Phase One is used in Phase Two experiments in order to recreate a polygonal model of a 3D printed object using all of the feature extraction methods. The KAZE algorithm achieved the lowest standard deviation and mean distance values of 0.0635 mm and −0.00921 mm, respectively.

scholarly journals 3D Reconstruction of Exposed Underground Utilities Using Photogrammetric Methods

2021 ◽  
Author(s):  
Wensong Hu
Keyword(s):  
3D Reconstruction ◽  
Digital Images ◽  
Low Cost ◽  
Three Dimensional ◽  
Lookup Table ◽  
Image Point ◽  
Digital Cameras ◽  
Study Results ◽  
Underground Utilities ◽  
3D Information

This thesis addresses the topic of three-dimensional (3D) reconstruction of exposed underground utilities using photogrammetric methods. Research on this topic is mainly motivated by the need for improved information on the location of underground utilities and, thus, to provide reliable information for the management of buried assets. In this thesis, a system of photogrammetric software programs is developed for 3D reconstruction of underground utilities. Camera calibration programs are used for computing interior elements and lens distortion coefficients of digital cameras and saving them in a lookup table (LUT). The accuracy of calibrated image coordinates satisfies the photogrammetric processing demand. An automatic image point detection method is proposed and achieved in these programs. External orientation programs are used for calculating exterior elements of the digital images. Based on geographic information system (GIS) and global positioning system (GPS) techniques, a new ground control points (GCPs) collection method is proposed and implemented in these programs. A 3D reconstruction program provides corresponding functions to obtain and edit 3D information of underground utilities. Epipolar lines are employed as an assisting tool that helps operators easily find homologous points from different digital images. The study results indicate that photogrammetric methods for reconstructing 3D information of underground utilities are effective and low cost.

scholarly journals 3D Reconstruction of Exposed Underground Utilities Using Photogrammetric Methods

2021 ◽  
Author(s):  
Wensong Hu
Keyword(s):  
3D Reconstruction ◽  
Digital Images ◽  
Low Cost ◽  
Three Dimensional ◽  
Lookup Table ◽  
Image Point ◽  
Digital Cameras ◽  
Study Results ◽  
Underground Utilities ◽  
3D Information

This thesis addresses the topic of three-dimensional (3D) reconstruction of exposed underground utilities using photogrammetric methods. Research on this topic is mainly motivated by the need for improved information on the location of underground utilities and, thus, to provide reliable information for the management of buried assets. In this thesis, a system of photogrammetric software programs is developed for 3D reconstruction of underground utilities. Camera calibration programs are used for computing interior elements and lens distortion coefficients of digital cameras and saving them in a lookup table (LUT). The accuracy of calibrated image coordinates satisfies the photogrammetric processing demand. An automatic image point detection method is proposed and achieved in these programs. External orientation programs are used for calculating exterior elements of the digital images. Based on geographic information system (GIS) and global positioning system (GPS) techniques, a new ground control points (GCPs) collection method is proposed and implemented in these programs. A 3D reconstruction program provides corresponding functions to obtain and edit 3D information of underground utilities. Epipolar lines are employed as an assisting tool that helps operators easily find homologous points from different digital images. The study results indicate that photogrammetric methods for reconstructing 3D information of underground utilities are effective and low cost.

scholarly journals Three-Dimensional Chipless RFID Tags: Fabrication through Additive Manufacturing

Sensors ◽  
2020 ◽  
Vol 20 (17) ◽  
pp. 4740
Author(s):  
Sergio Terranova ◽  
Filippo Costa ◽  
Giuliano Manara ◽  
Simone Genovesi
Keyword(s):  
Radio Frequency Identification ◽  
Low Cost ◽  
Three Dimensional ◽  
Rfid Tags ◽  
Metallic Surfaces ◽  
Data Encoding ◽  
Chipless Rfid ◽  
Frequency Identification ◽  
3D Printed ◽  
Promising Solution

A new class of Radio Frequency IDentification (RFID) tags, namely the three-dimensional (3D)-printed chipless RFID one, is proposed, and their performance is assessed. These tags can be realized by low-cost materials, inexpensive manufacturing processes and can be mounted on metallic surfaces. The tag consists of a solid dielectric cylinder, which externally appears as homogeneous. However, the information is hidden in the inner structure of the object, where voids are created to encrypt information in the object. The proposed chipless tag represents a promising solution for anti-counterfeiting or security applications, since it avoids an unwanted eavesdropping during the reading process or information retrieval from a visual inspection that may affect other chipless systems. The adopted data-encoding algorithm does not rely on On–Off or amplitude schemes that are commonly adopted in the chipless RFID implementations but it is based on the maximization of available states or the maximization of non-overlapping regions of uncertainty. The performance of such class of chipless RFID tags are finally assessed by measurements on real prototypes.

scholarly journals Structured-Light Based 3D Reconstruction System for Cultural Relic Packaging

Sensors ◽  
2018 ◽  
Vol 18 (9) ◽  
pp. 2981 ◽  
Author(s):  
Limei Song ◽  
Xinyao Li ◽  
Yan-gang Yang ◽  
Xinjun Zhu ◽  
Qinghua Guo ◽  
...  
Keyword(s):  
3D Reconstruction ◽  
High Efficiency ◽  
Low Cost ◽  
Structured Light ◽  
Three Dimensional ◽  
Cloud Data ◽  
Dimensional Measurement ◽  
Cost System ◽  
Three Dimensional Measurement ◽  
Cultural Relics

The non-contact three-dimensional measurement and reconstruction techniques have played a significant role in the packaging and transportation of precious cultural relics. This paper develops a structured light based three-dimensional measurement system, with a low-cost for cultural relics packaging. The structured light based system performs rapid measurements and generates 3D point cloud data, which is then denoised, registered and merged to achieve accurate 3D reconstruction for cultural relics. The multi-frequency heterodyne method and the method in this paper are compared. It is shown that the relative accuracy of the proposed low-cost system can reach a level of 1/1000. The high efficiency of the system is demonstrated through experimental results.

scholarly journals The Use of Gigapixel Photogrammetry for the Understanding of Landslide Processes in Alpine Terrain

Geosciences ◽  
2019 ◽  
Vol 9 (2) ◽  
pp. 99 ◽  
Author(s):  
Saverio Romeo ◽  
Lucio Di Matteo ◽  
Daniel Kieffer ◽  
Grazia Tosi ◽  
Aurelio Stoppini ◽  
...  
Keyword(s):  
3D Model ◽  
Low Cost ◽  
Three Dimensional ◽  
Image Sequences ◽  
Synthetic Aperture ◽  
Synthetic Aperture Radar Interferometry ◽  
Experimental Application ◽  
Single Lens ◽  
Landslide Processes ◽  
3D Information

The work in this paper illustrates an experimental application for geosciences by coupling new and low cost photogrammetric techniques: Gigapixel and Structure-from-Motion (SfM). Gigapixel photography is a digital image composed of billions of pixels (≥1000 megapixels) obtained from a conventional Digital single-lens reflex camera (DSLR), whereas the SfM technique obtains three-dimensional (3D) information from two-dimensional (2D) image sequences. The field test was carried out at the Ingelsberg slope (Bad Hofgastein, Austria), which hosts one of the most dangerous landslides in the Salzburg Land. The stereographic analysis carried out on the preliminary 3D model, integrated with Ground Based Synthetic Aperture Radar Interferometry (GBInSAR) data, allowed us to obtain the main fractures and discontinuities of the unstable rock mass.

A Novel Method for Automated Acquisition of Tilt Series for Electron Tomography Based on Pre-Calibration of the Specimen Stage

2000 ◽  
Vol 6 (S2) ◽  
pp. 1148-1149
Author(s):  
U. Ziese ◽  
A.H. Janssen ◽  
T.P. van der Krift ◽  
A.G. van Balen ◽  
W.J. de Ruijter ◽  
...  
Keyword(s):  
High Resolution ◽  
3D Reconstruction ◽  
Cell Biology ◽  
Electron Tomography ◽  
Three Dimensional ◽  
Imaging Method ◽  
3D Images ◽  
Tilt Series ◽  
3D Information ◽  
Structural Arrangements

Electron tomography is a three-dimensional (3D) imaging method with transmission electron microscopy (TEM) that provides high-resolution 3D images of structural arrangements. Conventional TEM images are in first approximation mere 2D-projections of a 3D sample under investigation. With electron tomographya series of images is acquired of a sample that is tilted over a large angular range (±70°) with small angular tilt increments (so called tilt-series). For the subsequent 3D-reconstruction, the images of the tilt series are aligned relative to each other and the 3D-reconstruction is computed. Electron tomography is the only technique that can provide true 3D information with nm-scale resolution of individual and unique samples. For (cell) biology and material science applications the availability of high-resolution 3D images of structural arrangements within individual samples provides unique architectural information that cannot be obtained otherwise. Routine application of electron tomography will comprise a major revolutionary step forward in the characterization of complex materials and cellular arrangements.

The Sparthan Three-Dimensional Printed Exo-Glove: A Preliminary Evaluation of Performance Via Case Study

2019 ◽  
Vol 13 (3) ◽  
Author(s):  
Tomás A. Georgiou ◽  
Davide Asnaghi ◽  
Alva Liang ◽  
Alice M. Agogino
Keyword(s):  
Light Intensity ◽  
Daily Living ◽  
Low Cost ◽  
Three Dimensional ◽  
Preliminary Evaluation ◽  
Evaluation Of Performance ◽  
3D Printed ◽  
Hand Exoskeleton ◽  
And Performance

This paper describes the development and testing of a low-cost three-dimensional (3D) printed wearable hand exoskeleton to assist people with limited finger mobility and grip strength. The function of the presented orthosis is to support and enable light intensity activities of daily living and improve the ability to grasp and hold objects. The Sparthan Exoskeleton prototype utilizes a cable-driven design applied to individual digits with motors. The initial prototype is presented in this paper along with a preliminary evaluation of durability and performance efficacy.

Wavelet-Based Surface Analysis for Form Feature Extraction

2000 ◽  
Author(s):  
Lei Sun ◽  
Abir Qamhiyah
Keyword(s):  
Feature Extraction ◽  
Wavelet Transforms ◽  
Three Dimensional ◽  
Feature Representation ◽  
Cad Model ◽  
Vanishing Moments ◽  
Planar Surfaces ◽  
Solid Models ◽  
Form Features ◽  
Form Feature

Abstract A new procedure for extracting form features from solid models with non-planar surfaces is presented in this paper. In the procedure, a surface is selected as the unit for feature representation, i.e. “feature primitive.” Three-dimensional wavelet transforms are applied to code and classify surfaces in a CAD model. Form features are then extracted by clustering the coded surfaces. Two wavelet bases, Harr and Daubechies with different vanishing moments, have been implemented. An example is presented to demonstrate the proposed procedure.

Three-Dimensional Printing of Prenatal Ultrasonographic Diagnosis of Cleft Lip and Palate: Presenting the Needed “Know-How” and Discussing Its Use in Parental Education

2020 ◽  
Vol 57 (8) ◽  
pp. 1041-1044
Author(s):  
Matthias Schlund ◽  
Jean-Marc Levaillant ◽  
Romain Nicot
Keyword(s):  
Parental Education ◽  
Cleft Lip ◽  
Cleft Lip And Palate ◽  
Three Dimensional ◽  
3D Models ◽  
Prenatal Counseling ◽  
Three Dimensional Printing ◽  
3D Printed ◽  
3D Information ◽  
Dimensional Printing

Parental prenatal counseling is of paramount significance since parents often experience an emotional crisis with feelings of disappointment and helplessness. Three-dimensional (3D) printed model of the unborn child’s face presenting with cleft lip and palate, based on ultrasonographic information, could be used to provide visual 3D information, further enhancing the prospective parent’s comprehension of their unborn child’s pathology and morphology, helping them to be psychologically prepared and improving the communication with the caretaking team. Prospective parents appreciate if prenatal counseling is available with the most detailed information as well as additional resources. The technique necessary to create 3D models after ultrasonographic information is explained, and the related costs are evaluated. The use of such models in parental education is then discussed.

scholarly journals Development of a Low-Cost EEG-Controlled Hand Exoskeleton 3D Printed on Textiles

2021 ◽  
Vol 15 ◽  
Author(s):  
Rommel S. Araujo ◽  
Camille R. Silva ◽  
Severino P. N. Netto ◽  
Edgard Morya ◽  
Fabricio L. Brasil
Keyword(s):  
Low Cost ◽  
Three Dimensional ◽  
Training Session ◽  
Life Quality ◽  
Motor Deficits ◽  
Stroke Survivors ◽  
Motor Rehabilitation ◽  
3D Printed ◽  
Hand Exoskeleton ◽  
Robotic Devices

Stroke survivors can be affected by motor deficits in the hand. Robotic equipment associated with brain–machine interfaces (BMI) may aid the motor rehabilitation of these patients. BMIs involving orthotic control by motor imagery practices have been successful in restoring stroke patients' movements. However, there is still little acceptance of the robotic devices available, either by patients and clinicians, mainly because of the high costs involved. Motivated by this context, this work aims to design and construct the Hand Exoskeleton for Rehabilitation Objectives (HERO) to recover extension and flexion movements of the fingers. A three-dimensional (3D) printing technique in association with textiles was used to produce a lightweight and wearable device. 3D-printed actuators have also been designed to reduce equipment costs. The actuator transforms the torque of DC motors into linear force transmitted by Bowden cables to move the fingers passively. The exoskeleton was controlled by neuroelectric signal—electroencephalography (EEG). Concept tests were performed to evaluate control performance. A healthy volunteer was submitted to a training session with the exoskeleton, according to the Graz-BCI protocol. Ergonomy was evaluated with a two-dimensional (2D) tracking software and correlation analysis. HERO can be compared to ordinary clothing. The weight over the hand was around 102 g. The participant was able to control the exoskeleton with a classification accuracy of 91.5%. HERO project resulted in a lightweight, simple, portable, ergonomic, and low-cost device. Its use is not restricted to a clinical setting. Thus, users will be able to execute motor training with the HERO at hospitals, rehabilitation clinics, and at home, increasing the rehabilitation intervention time. This may support motor rehabilitation and improve stroke survivors life quality.

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