Hybrid Focal Stereo Networks for Pattern Analysis in Homogeneous Scenes

In this paper we address the problem of multiple camera calibration in the presence of a homogeneous scene, and without the possibility of employing calibration object based methods. The proposed solution exploits salient features present in a larger field of view, but instead of employing active vision we replace the cameras with stereo rigs featuring a long focal analysis camera, as well as a short focal registration camera. Thus, we are able to propose an accurate solution which does not require intrinsic variation models as in the case of zooming cameras. Moreover, the availability of the two views simultaneously in each rig allows for pose re-estimation between rigs as often as necessary. The algorithm has been successfully validated in an indoor setting, as well as on a difficult scene featuring a highly dense pilgrim crowd in Makkah.Comment: 13 pages, 6 figures, submitted to Machine Vision and Application

LiDAR Scanning with Supplementary UAV Captured Images for Structural Inspections

Structural assessment using remote sensing technologies can be performed efficiently and effectively using such technologies as LiDAR (light detection and ranging). LiDAR can be employed for various structural assessments, such as as-built conditions for a newly constructed facility, routine inspection during its service life, or structural collapse evaluation after a natural hazard or extreme event. However, the main disadvantage of LiDAR is that it is a line-of-sight technology that can result in significant occlusions. Architectural or structural components can be partially or fully occluded by another object with respect to the location of the laser scanner. Supplemental photogrammetry techniques, such as structure from motion (SfM), can be introduced into the workflow to reduce the occlusion in the final result. Since high-resolution cameras have the ability to be mounted on unmanned aerial vehicles (UAVs), typical areas of occlusion associated with ground-based LiDAR and supported structural coverings (e.g. roof or bridge deck) can be reconstructed. In this approach, aerial SfM is selected due to the low investment and operational costs in comparison to airborne LiDAR. This paper demonstrates the techniques and results of both LiDAR and aerial SfM for a case study building. Images captured with a UAV supplement the collected LiDAR and allow for a holistic scene reconstruction. The benefits of deployment of a combined remote sensing platform, such as this, are demonstrated in the case of reconnaissance in the aftermath of extreme events

Efficient lens distortion correction for decoupling in calibration of wide angle lens cameras

© 2013 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works.In photogrammetry applications, camera parameters must be as accurate as possible to avoid deviations in measurements from images. Errors increase if wide angle lens cameras are used. Moreover, the coupling between intrinsic and extrinsic camera parameters and the lens distortion model influences the result of the calibration process notably. This paper proposes a method for calibrating wide angle lens cameras, which takes into account the existing hard coupling. The proposed method obtains stable results, which do not depend on how the image lens distortion is corrected.This work was supported in part by the Universidad Politecnica de Valencia research funds (PAID 2010-2431 and PAID 10017), the Generalitat Valenciana (GV/2011/057) and the Spanish government and the European Community under Project DPI2010-20814-C02-02 (FEDER-CICYT) and Project DPI2010-20286 (CICYT). The associate editor coordinating the review of this paper and approving it for publication was Dr. Subhas C. Mukhopadhyay.Ricolfe Viala, C.; Sánchez Salmerón, AJ.; Valera Fernández, Á. (2013). Efficient lens distortion correction for decoupling in calibration of wide angle lens cameras. IEEE Sensors Journal. 13(2):854-863. https://doi.org/10.1109/JSEN.2012.2229704S85486313

Алгоритми компенсації оптичних спотворень на цифрових зображеннях

До бакалаврської дипломної роботи Перцова Вадим Миколайовича. На тему: «Алгоритми компенсації оптичних спотворень на цифрових зображеннях» Дана дипломна робота присвячена методам компенсації оптичних спотворень на цифрових зображеннях. В роботі зроблено аналіз алгоритмів компенсації оптичних спотворень та визначення найбільш оптимальних методів компенсації для цифрових зображеннях. Аналіз проводиться в пакеті прикладних програм MATLAB.This thesis is devoted to algorithms for compensating optical distortion of digital images. The paper analyzes the methods of optical distortion compensation and determines the most optimal compensation methods for digital images. The analysis is performed in the MATLAB application package