Proceedings, XXth congress: Proceedings, XXth congress

Altan, M. Orhan

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Multivolume work

Persistent identifier:: 1663674213

Title:: Proceedings, XXth congress

Sub title:: Istanbul, 12 - 23 July 2004

Year of publication:: 2004

Place of publication:: Istanbul

Publisher of the original:: [Verlag nicht ermittelbar]

Identifier (digital):: 1663674213

Language:: English

Additional Notes:: Erscheinungsdatum des Originals ist aus dem Copyrightjahr ermittelt.; Auch bezeichnet als XXth International Congress for Photogrammetry and Remote Sensing

Editor:: Altan, M. Orhan

Corporations:: International Society for Photogrammetry and Remote Sensing, Congress, 20., 2004, Istanbul; International Society for Photogrammetry and Remote Sensing, Commission Primary Data Acquisition

Adapter:: International Society for Photogrammetry and Remote Sensing, Congress, 20., 2004, Istanbul; International Society for Photogrammetry and Remote Sensing, Commission Primary Data Acquisition

Founder of work:: International Society for Photogrammetry and Remote Sensing, Congress, 20., 2004, Istanbul; International Society for Photogrammetry and Remote Sensing, Commission Primary Data Acquisition

Other corporate:: International Society for Photogrammetry and Remote Sensing, Congress, 20., 2004, Istanbul; International Society for Photogrammetry and Remote Sensing, Commission Primary Data Acquisition

Document type:: Multivolume work

Volume

Persistent identifier:: 166368779X

Title:: Proceedings, XXth congress

Scope:: IV, 226 Seiten

Year of publication:: 2004

Place of publication:: Istanbul

Publisher of the original:: [Verlag nicht ermittelbar]

Identifier (digital):: 166368779X

Illustration:: Illustrationen, Diagramme

Signature of the source:: ZS 312(35,B8)

Language:: English

Additional Notes:: Erscheinungsdatum des Originals ist aus dem Copyrightjahr ermittelt.

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

Editor:: Altan, M. Orhan

Corporations:: International Society for Photogrammetry and Remote Sensing, Congress, 20., 2004, Istanbul; International Society for Photogrammetry and Remote Sensing

Adapter:: International Society for Photogrammetry and Remote Sensing, Congress, 20., 2004, Istanbul; International Society for Photogrammetry and Remote Sensing

Founder of work:: International Society for Photogrammetry and Remote Sensing, Congress, 20., 2004, Istanbul; International Society for Photogrammetry and Remote Sensing

Other corporate:: International Society for Photogrammetry and Remote Sensing, Congress, 20., 2004, Istanbul; 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:: CLOSE-RANGE PHOTOGRAMMETRY WITH AMATEUR CAMERA Dimitar Jechev

Document type:: Multivolume work

Structure type:: Chapter

and total of a cture te of bject ) one | be (1) nts, lon, the co- mage f the nt 1, International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences, Vol XXXV, Part B-YF. Istanbul 2004 Mi Hs UP R=im, My My (3) à Hy Hy A system of kind (2) could be composed for each measured image point i. This means that if the object is photographed by one stereo-pair, each point from the object would originate two systems of kind (2) or in total 4 equations, since each point is appeared on two photographs. 1.4. Unknown quantities In case that the survey is performed by a metric camera, each bundle (photograph) contains 6 unknowns: the tree rotation angles «y $ and «, defining the matrix AR, and co-ordinates (X,, Yo, Zo) of the projection centre O. Since each measured image point originates 2 equations, in order to define synonymously one bundle, 3 control points are sufficient. Also 3 points are sufficient for calculation of one stereo-pair, as long as the points are located in the overlapping area of the photographs. In case that a non-metric camera is used, the elements of internal orientation x,, yo and f are not defined, which means that the unknowns for each bundle get increased with 3. In order to secure a synonymous solution for the 9 equations, 5 control points are needed. Since the number of equations usually is larger than the minimum required and the measured image co- ordinates contain casual errors, the least squares adjustment is applied. 1.5. Additional parameters Lens distortion, as well as some other possible defects of the camera, are origin for systematic errors in image co-ordinates, because the images get drawn away from correct central projection. One of the conditions of the least squares adjustment is that the adjusted quantities should not contain systematic errors. With amateur cameras, as distinct to professional cameras, these defects may have significant values and hence may considerably disturb the processing. If the lens distortion is known, the image co-ordinates may be adjusted before the bundle adjustment. This process is know as image refining. Even in case of some distortion, the refining is ineffective, because with non-metric cameras it gets changed in time. It is more effective for the image defects to be reduced by introduction of additional parameters into the mathematical instrument: m (X, = X,)+m,(Y, = Y) +m, (2, = Zu) - X,)* m, tr, -Y,)«m,(Z, 23 (4) my, (X, = X,)* m, (y, = Y), + My; (Z, = Zi} Yep, tA =f v=o + dy, == : me t f m, (X, = X,)* m, 17 SE y, )+ m,,(Z, 7 20) where the additional parameters Ax, and Ay, are function of some unknowns and take part in adjustment together with the rest of unknowns. The selection of additional parameters is based on two contradictory principles: e The number of parameters should be as less as possible, in order to reduce the number of control points, and respectively to reduce the volume of calculations. 137 e. The number of parameters should be as large as necessary to ensure minimum co-relation with the other unknowns. Otherwise it is possible for the normal matrix to get degenerated. - In contrast to the traditional photogrammetry, where the additional parameters may be considered as constants for all photographs within a block or at least for a group of photographs, the use of non-metric cameras may require a full set of additional parameters for each single photograph. This leads to an increase of the amount of calculations, which however is not a serious problem, because the blocks made by non-metric cameras usually are smal. 2. EXPERIMENT An experiment has been conducted, aiming to determine what accuracy may be reached at close-range photogrammetry when non-metric digital camera with unknown elements of internal orientation and distortion of lens is in use. 2.1. Surveying The frontage of a residential building, located in City of Sofia, has been surveyed by a total station Leica TC 1610 geodetically. By means of intersections 55 not marked survey points have been defined. The error of their location is within the range of +0.5 cm. The same frontage have been surveyed photogrammetrically with one stereo-pair. The distance beteen the camera and the object is about 20 m, while the distance between the two projection centres is about 4 m. The main camera optical rays + 23m + =n ç | | B, 20m JB 9—9o A | 1 4m | so 5. y ++ 4m B,B» - geodetic basis S, S2 - projection centre Figure 1. Survey performance are approximately parallel and inclining towards the vertical plane. The pictures has been taken by means of an amateur digital non-metric camera Canon S230 with a focal lenght, corresponding approximately to 35 mm and size of 3 mega pixels of the photographs. 2.2. Processing The images have been processed by PHOTOMOD Lite — a photogrammetric software of Racurs Co., allowing operations with non-metric cameras. The calibration with this software is done during the processing. The lens distortion can be taken into consideration only in case that it has been defined before hand. For the purposes of this experiment, the orientation of the stereo-model has been conducted by means of 8 control points and 30 tie points. The lens distorsion is unknown. For the sake of reduction of distortion influence, the edge zones of the

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