XXII ISPRS Congress 2012: Technical Commission VII

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Multivolume work

Persistent identifier:: 1663813779

Title:: XXII ISPRS Congress 2012

Sub title:: Melbourne, Australia, 25 August-1 September 2012

Year of publication:: 2013

Place of publication:: Red Hook, NY

Publisher of the original:: Curran Associates, Inc.

Identifier (digital):: 1663813779

Language:: English

Additional Notes:: Kongress-Thema: Imaging a sustainable future

Corporations:: International Society for Photogrammetry and Remote Sensing, Congress, 22., 2012, Melbourne; International Society for Photogrammetry and Remote Sensing

Adapter:: International Society for Photogrammetry and Remote Sensing, Congress, 22., 2012, Melbourne; International Society for Photogrammetry and Remote Sensing

Founder of work:: International Society for Photogrammetry and Remote Sensing, Congress, 22., 2012, Melbourne; International Society for Photogrammetry and Remote Sensing

Other corporate:: International Society for Photogrammetry and Remote Sensing, Congress, 22., 2012, Melbourne; International Society for Photogrammetry and Remote Sensing

Document type:: Multivolume work

Volume

Persistent identifier:: 1663821976

Title:: Technical Commission VII

Scope:: 546 Seiten

Year of publication:: 2013

Place of publication:: Red Hook, NY

Publisher of the original:: Curran Associates, Inc.

Identifier (digital):: 1663821976

Illustration:: Illustrationen, Diagramme

Signature of the source:: ZS 312(39,B7)

Language:: English

Additional Notes:: Erscheinungsdatum des Originals ist ermittelt.; Literaturangaben

Usage licence:: Attribution 4.0 International (CC BY 4.0)

Corporations:: International Society for Photogrammetry and Remote Sensing, Congress, 22., 2012, Melbourne; International Society for Photogrammetry and Remote Sensing

Adapter:: International Society for Photogrammetry and Remote Sensing, Congress, 22., 2012, Melbourne; International Society for Photogrammetry and Remote Sensing

Founder of work:: International Society for Photogrammetry and Remote Sensing, Congress, 22., 2012, Melbourne; International Society for Photogrammetry and Remote Sensing

Other corporate:: International Society for Photogrammetry and Remote Sensing, Congress, 22., 2012, Melbourne; International Society for Photogrammetry and Remote Sensing

Publisher of the digital copy:: Technische Informationsbibliothek Hannover

Place of publication of the digital copy:: Hannover

Year of publication of the original:: 2019

Document type:: Volume

Collection:: Earth sciences

Chapter

Title:: [VII/5: METHODS FOR CHANGE DETECTION AND PROCESS MODELLING]

Document type:: Multivolume work

Structure type:: Chapter

Chapter

Title:: A SEMIAUTOMATIC ANOMALOUS CHANGE DETECTION METHOD FOR MONITORING AIMS G. Artese, V. Achilli, M. Fabris, M. Perrelli

Document type:: Multivolume work

Structure type:: Chapter

O of king International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences, Volume XXXIX-B7, 2012 XXII ISPRS Congress, 25 August — 01 September 2012, Melbourne, Australia A SEMIAUTOMATIC ANOMALOUS CHANGE DETECTION METHOD FOR MONITORING AIMS G.Artese*, V. Achilli?, M. Fabris", M.Perrelli* * Land Planning Dept. - University of Calabria - Ponte Bucci cubo 45B - 87036 - Rende - Italy (g.artese, marcello.perrelli)@unical.it 5 s9** Dept. - University of Padua - Via Marzolo ** Commission VII, WG VII/5 KEY WORDS: Change Detection, Image Processing, Registration, Cultural Heritage, Camera Phone. ABSTRACT: In the framework of the development of a web site devoted to the documentation and monitoring of the cultural heritage (above all monumental buildings), a semiautomatic method for anomalous change detection has been set up. The method uses the grouping of the image difference values, to detect both small and diffused changes. Three tests are described to evaluate the performances of the method. The results show that good performances are obtained in case of cloudy days, while the presence of shadows requires the interpretation of an operator to distinguish true and false changes. 1. INTRODUCTION In the framework of the development of a web site devoted to the documentation and monitoring of the cultural heritage (above all monumental buildings), with particular regard to emergency management, anomaly detection and early warning (Artese,G., Gencarelli,M., 2008), a semiautomatic method for anomalous change detection has been set up. The system uses images captured and sent by camera phones; these images are compared with archived ones to detect anomalous changes and, consequently, to activate an early warning procedure. The availability of high resolution digital cameras combined with the possibilities offered by today's computers, both for camera calibration and image processing, allows the execution of controls and monitoring by using change detection techniques, based on the comparison of frames acquired at different times. The use of these techniques is widespread in various sectors, ranging from security to traffic monitoring, to the processing of radiographic images, etc.. . The issues involved range from the calibration of the cameras used, to the feature extraction, registration, and actual change detection. Some authors have proposed techniques that do not require prior calibration and optimal resampling (registration) and make use of the classification process of pixels (Theiler, J., Perkins, S., 2006). 1.1 Calibration Many algorithms have been proposed for automatic calibration of the images. For example, Cronk et al. (Cronk, S., 2006) have proposed an effective method in the case of many converging acquisitions. Another possibility is to consider non-rigid geometric deformations, due to lens distortion; for such a case Arsigny et al. (Arsigny, V., 2006) have proposed a general methodology to parameterize the deformation of the image with a finite number of rigid or affine components, while maintaining the reversibility of the global deformation. Considering the presence of flat surfaces and straight lines, different strategies can be followed. Habib et al. (Habib, AS, 2002, Habib, AS, 2004, Habib, AS, 2005) have proposed a method for both calibration and registration, based on the use of straight lines. In the case of monitoring, internal and external orientation parameters are known, at least for a base image. In our work, straight lines were used during calibration of the camera lens to eliminate distortion, after having obtained the outlines with classical technique (Canny, J., 1986). 1.2 Identification of interest points To obtain a good image registration, you must choose a set of interest points, which must be visible, and whose image coordinates must be known or measurable. For monitoring aims, one has in general the availability of one or more images in which interest points are detected through automatic or manual techniques. The classical operators Forstner (Forstner, W., 1987) Harris (Harris, CG, 1988) and Moravec (Moravec, HP, 1979) can be used effectively. In our work we used a semiautomatic technique, along with the operators of Harris and Moravec. 1.3 Cross-correlation To perform registration, of fundamental importance for change detection, it is essential to find, in the images obtained at later dates, the interest points which were chosen in the base frames. For this purpose you can use the matching techniques. Among these, the cross-correlation is simple and effective (Jaehne, B., 1989). The cross-correlation allows to obtain the correspondence between two digital images, based on two assumptions: the images differ geometrically only due to a translation and radiometrically only for brightness and contrast. The accuracy of the cross-correlation decreases rapidly when the geometric assumptions are not met, especially when you have rotations greater than 20? or differences in scale greater than 30% (Forstner, W., 1984). The different perspectives of the images to compare cause both translations and rotations. For the buildings, it's in general

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