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The paper presents a home-made 3d scanner, consisting of off-the-shelf components: a camera and a projector. It is intended for
monitoring dynamics of riverbed mophology observed under laboratory conditions in a flume, which is currently under construction.
Special attention is paid to satisfying high requirements concerning accuracy and precision...
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In this work, a comparison of the performances of a stereo and a monocular vision system for the 3D pose estimation of a planar target in very challenging conditions is presented. In particular, the systems have been designed to detect in real time a target moving with a maximum speed of 1 m/s, in a range of distances from 0.5 to 4 m from the camer...
Citations
... In [286], in order to reduce the computational complexity of BA, an Reduced BA (RBA) algorithm was proposed, which is comparatively slightly less accurate, and corrects the camera poses based on their oblique and nadir parameters. In [147], a flume under construction was monitored using a homemade scanner, which consisted of a camera and a projector, benefiting from a rather high precision and accuracy, given the compact setup offered. According to [272], using high-speed video cameras [301,244] or stroboscopic illumination [271] along with 3D image correlation photogrammetry may lead to an approach to measurements of full-field stress, strain, deformation and displacement. ...
Virtual fitting constitutes a fundamental element of the developments expected to rise the commercial prosperity of online garment retailers to a new level, as it is expected to reduce the load of the manual labor and physical efforts required. Nevertheless, most of the previously proposed computer vision and graphics methods have failed to accurately and realistically model the human body, especially, when it comes to the 3D modeling of the whole human body. The failure is largely related to the huge data and calculations required, which in reality is caused mainly by inability to properly account for the simultaneous variations in the body surface. In addition, most of the foregoing techniques cannot render realistic movement representations in real-time. This project intends to overcome the aforementioned shortcomings so as to satisfy the requirements of a virtual fitting room. The proposed methodology consists in scanning and performing some specific analyses of both the user’s body and the prospective garment to be virtually fitted, modeling, extracting measurements and assigning reference points on them, and segmenting the 3D visual data imported from the mannequins. Finally, super-imposing, adopting and depicting the resulting garment model on the user’s body. The project is intended to gather sufficient amounts of visual data using a 3D laser scanner and the Kinect optical camera, to manage it in form of a usable database, in order to experimentally implement the algorithms devised. The latter will provide a realistic visual representation of the garment on the body, and enhance the size-advisor system in the context of the virtual fitting room under study.
... One of the applications of PaRS is in improving the speed and accuracy of progress reporting, where a construction site is scanned regularly, and the scans are compared to each other, as well as to the planned outcome, in order to measure the amount of work done quantitatively, and help make management and control decisions [14]. A homemade 3D scanner consisting of a camera and a projector was built in [15], aiming at relatively high levels of accuracy and precision, as well as a compact and dexterous setup. As a case-study, the system was utilized for monitoring a flume under construction. ...
This paper provides an overview of 3D scanning methodologies and technologies proposed in the existing scientific and industrial literature. Throughout the paper, various types of the related techniques are reviewed, which consist, mainly, of close-range, aerial, structure-from-motion and terrestrial photogrammetry, and mobile, terrestrial and airborne laser scanning, as well as time-of-flight, structured-light and phase-comparison methods, along with comparative and combinational studies, the latter being intended to help make a clearer distinction on the relevance and reliability of the possible choices. Moreover, outlier detection and surface fitting procedures are discussed concisely, which are necessary post-processing stages.
... system in which, instead of using two cameras with a parallax distance, a camera and a projection unit are used, see Figure 1a. Geometry configuration and the calibration procedure of the CP-3D scanner set of parameters were performed as described by Gorte et al. (2013). The characteristics of the devices used in the CP-3D scanner construction shown in Figure 1a are summarized in Table 1. ...
... As the surface presents 3D faces, the projected patterns will appear distorted in the acquired images. This 'distortion' of the pattern's original positions in the camera image is analyzed by using photogrammetric equations to construct a 3D point cloud that represent the shape of the surface, see Gorte et al. (2013). ...
This paper presents the results of measuring bed topography through water in mobile-bed laboratory flumes with two different techniques: structured light and 3D laser scanning. The refraction phenomenon is considered and corrections are applied. Results of this work show that the applicability of the considered measurement techniques for applications in laboratory experiments is restricted to certain flow conditions. Improvements in the corrections of the refraction effects and detailed water level measurements are special aspects to consider before implementing laboratory campaigns with such techniques.
Photogrammetry uses images of a three-dimensional structure to derive information about its shape and position. In this work, a photogrammetric technique is implemented with a single camera and a digital projector to measure changes in an underwater sediment bed. This implementation incorporates refraction at an interface allowing for measurements through a deformed or changing water surface. The digital projector provides flexibility in choosing projected patterns and has a high frame rate, which allows to easily increase the spatial and temporal resolution of the measurements. The technique requires first for both the camera and the projector to be calibrated using triangulation. With the calibration, we construct lines in three-dimensional space that originate from the projector and the camera, and intersect on the surface to be measured. To correctly incorporate refraction due to a change of medium, each line in space is recalculated from its intersection with the interface using Snell’s law. This has the benefit that only one calibration for measurements is needed if the location and shape of the interface are known. The technique is validated by measuring a submerged undulated surface, plastic objects and a sediment bed. In particular, the undulated plate is reconstructed under a flat and a parabolic water surface. Finally, the technique is used in combination with particle image velocimetry to dynamically measure a changing sediment bed under an oscillating flow and the flow velocity at the free surface.
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