scholarly journals Dense matching using correlation: new measures that are robust near occlusions

Author(s):  
S. Chambon ◽  
A. Crouzil
Keyword(s):  
2019 ◽  
Vol 55 (7) ◽  
pp. 380-382 ◽  
Author(s):  
Di Jia ◽  
Si Wu ◽  
Mingyuan Zhao

2011 ◽  
Vol 6 ◽  
pp. 275-282 ◽  
Author(s):  
C. Re ◽  
S. Robson ◽  
R. Roncella ◽  
M Hess

In the cultural heritage field the recording and documentation of small and medium size objects with very detailed Digital Surface Models (DSM) is readily possible by through the use of high resolution and high precision triangulation laser scanners. 3D surface recording of archaeological objects can be easily achieved in museums; however, this type of record can be quite expensive. In many cases photogrammetry can provide a viable alternative for the generation of DSMs. The photogrammetric procedure has some benefits with respect to laser survey. The research described in this paper sets out to verify the reconstruction accuracy of DSMs of some archaeological artifacts obtained by photogrammetric survey. The experimentation has been carried out on some objects preserved in the Petrie Museum of Egyptian Archaeology at University College London (UCL). DSMs produced by two photogrammetric software packages are compared with the digital 3D model obtained by a state of the art triangulation color laser scanner. Intercomparison between the generated DSM has allowed an evaluation of metric accuracy of the photogrammetric approach applied to archaeological documentation and of precision performances of the two software packages.


2016 ◽  
Vol 12 (12) ◽  
pp. 155014771668082
Author(s):  
Fanhuai Shi ◽  
Jian Gao ◽  
Xixia Huang

Visual sensor networks have emerged as an important class of sensor-based distributed intelligent systems, where image matching is one of the key technologies. This article presents an affine invariant method to produce dense correspondences between uncalibrated wide baseline images. Under affine transformations, both point location and its neighborhood texture are changed between views, so dense matching becomes a tough task. The proposed approach tends to solve this problem within a sparse-to-dense framework. The contribution of this article is in threefolds. First, a strategy of reliable sparse matching is proposed, which starts from affine invariant features extraction and matching and then these initial matches are utilized as spatial prior to produce more sparse matches. Second, match propagation from sparse feature points to its neighboring pixels is conducted in the way of region growing in an affine invariant framework. Third, the unmatched points are handled by low-rank matrix recovery technique. Comparison experiments of the proposed method versus existing ones show a significant improvement in the presence of large affine deformations.


2016 ◽  
Author(s):  
Christoph Beekmans ◽  
Johannes Schneider ◽  
Thomas Läbe ◽  
Cyrill Stachniss ◽  
Clemens Simmer

Abstract. In this paper, we present our approach for dense 3D cloud reconstruction using two hemispheric sky imagers with fisheye lenses in a stereo setup. Fisheye lenses follow a different projection function than classical pinhole-type cameras, which provide a large field of view with a single image, but also renders the computation of dense 3D information more complicated, such that we cannot rely entirely on standard implementations for dense 3D stereo reconstruction. In this work, we examine the epipolar rectification model, which allows the use of dense matching algorithms designed for classical perspective cameras to search for disparity information at every pixel. Together with an appropriate camera calibration, which includes internal camera geometry and global position and orientation of the stereo camera pair, we can use the disparity information for dense 3D stereo reconstruction of the a cloud and thus estimate its shape. From the obtained 3D shapes, cloud dynamics, size, motion, type and spacing can be derived and used e.g. for radiation closure under cloudy conditions. We implemented and evaluated the proposed approach using real world data and present two case studies. In the first case, we validate the quality and accuracy of the method by comparing the stereo reconstruction of a stratocumulus layer with the reflectivity observations measured by a cloud radar and the cloud base height estimated from a Lidar-ceilometer. The second case analyzes a rapid cumulus convection in the presence of strong wind shear.


2012 ◽  
Vol E95.D (7) ◽  
pp. 2021-2024 ◽  
Author(s):  
Yanli WAN ◽  
Zhenjiang MIAO ◽  
Zhen TANG ◽  
Lili WAN ◽  
Zhe WANG
Keyword(s):  

Author(s):  
E. Dall'Asta ◽  
R. Roncella

Encouraged by the growing interest in automatic 3D image-based reconstruction, the development and improvement of robust stereo matching techniques is one of the most investigated research topic of the last years in photogrammetry and computer vision.<br><br> The paper is focused on the comparison of some stereo matching algorithms (local and global) which are very popular both in photogrammetry and computer vision. In particular, the Semi-Global Matching (SGM), which realizes a pixel-wise matching and relies on the application of consistency constraints during the matching cost aggregation, will be discussed.<br><br> The results of some tests performed on real and simulated stereo image datasets, evaluating in particular the accuracy of the obtained digital surface models, will be presented. Several algorithms and different implementation are considered in the comparison, using freeware software codes like MICMAC and OpenCV, commercial software (e.g. Agisoft PhotoScan) and proprietary codes implementing Least Square e Semi-Global Matching algorithms. The comparisons will also consider the completeness and the level of detail within fine structures, and the reliability and repeatability of the obtainable data.


Author(s):  
G. Di Gregorio

<p><strong>Abstract.</strong> The ancient theatres in Sicily, in southern Italy and along the countries facing the Mediterranean Sea basin, constitute a reality of incomparable cultural value. Regarding the research on the ancient theatres of eastern Sicily, few studies have been recently dealt with different methodologies. In the last years some practices have been done using 3D laser scanners for the theatres of Syracuse, Taormina and Morgantina, as well as the Syracuse amphitheatre and Taormina Odeon, just obtaining very interesting results. Lately the theatre of Palazzolo Acreide (Syracuse) has been studied, with Structure From Motion (SFM) and Dense Matching methodologies. From these experience, conclusions could be drawn on the quality and reliability of the elaborations realised with the SFM methodologies. We really know that these systems are today representing one of the fastest growing areas of examination, on which several software houses are investing. The study was chosen both for the small size of the building, and for the particular geometric conditions typical of the architecture of ancient theatres. This because their three-dimensional trend varies continually in the three variables X, Y, Z. The purpose of the work was to check whether the latest releases of these systems of survey allow today more than yesterday, a rapid digitalization and representation of the enormous archaeological cultural heritage. Various software were used, to verify the practicality and operation, the choice then fell on the Zephyr of 3DFlow, kindly available by the manufacturer, whose results were quite agreeable. The possibility offered by the program of a graphical tracing of polylines on the textured 3D model, has been a considerable advantage. Therefore the results obtained by modeling and surveying of the Palazzolo Acreide theatre have been compared, with the survey of the Syracuse, Taormina and Morgantina theatre performed using 3D laser scanners. First results of the research are matter of the following work.</p>


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