XVIIIth Congress: XVIIIth Congress

Kraus, Karl; Waldhäusl, Peter

Bibliographic data

Multivolume work

Persistent identifier:: 1667435949

Title:: XVIIIth Congress

Sub title:: Vienna, Austria 1996

Type of content:: Konferenzschrift

Year of publication:: 1996

Place of publication:: Vienna

Publisher of the original:: Austrian Society of Surveying and Geoinformation

Identifier (digital):: 1667435949

Reihe:: International archives of photogrammetry and remote sensing

Language:: English

Editor:: Kraus, Karl; Waldhäusl, Peter

Author:: International Society for Photogrammetry and Remote Sensing, 18.; 1996; Wien

Contributor:: International Society for Photogrammetry and Remote Sensing

Document type:: Multivolume work

Volume

Persistent identifier:: 1667437070

Title:: XVIIIth Congress

Scope:: 230 Seiten

Type of content:: Konferenzschrift

DOI:: 10.14463/KXP:1667437070

Year of publication:: 1996

Place of publication:: Vienna

Publisher of the original:: Austrian Society of Surveying and Geoinformation

Identifier (digital):: 1667437070

Illustration:: Illustrationen, Diagramme

Reihe:: International Archives of Photogrammetry and Remote Sensing (31,B1)

Signature of the source:: ZS 312(31,B1)

Language:: English

Additional Notes:: Erscheinungsdatum des Originals ist anhand des Copyrightjahrs ermittelt.

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

Editor:: Kraus, Karl; Waldhäusl, Peter

Author:: International Society for Photogrammetry and Remote Sensing, 18.; 1996; Wien

Contributor:: International Society for Photogrammetry and Remote Sensing; International Society for Photogrammetry and Remote Sensing, Commission Primary Data Acquisition

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:: GEOMETRIC AND RADIOMETRIC ANALYSIS OF A PHOTOGRAMMETRIC IMAGE SCANNER Bolte, Uwe, Jacobsen, Karsten, Wehrmann, Hagen

Document type:: Multivolume work

Structure type:: Chapter

y data oss of naster e gray e dark ausing 2 blue CCD- for all juest for ry 1995. it source ed. with le. The arts are cing the M1 The general geometric design is corresponding to an analytical plotter. The movement of the photo carrier is controlled by servos based on linear encoders. The plate is moved by a friction drive. With a working space of 245mme245mm no problems for handling standard size aerial images are existing. The used time delay and integration sensor (TDI) DALSA CL-E1-2048A has a length of 2048 elements and integrates over 96 pixels, that means, it is not a line, it is an array with 2048e96 elements. The integration of the TDI-sensor over 96 elements reduces the noise and systematic line errors by the factor of 96 and raises the sensitivity 80 times against an individual CCD-element. This sensor is also used in another photogrammetric image scanner. The RM1 is using only 1024 of the 2048 rows. The active part can be selected by the scanner control data, usually the center part is used. The sensor has no possibility for a selection of the spectral range, this only can be done by a computer controlled filter wheel with the standard red/green/blue selection. The transmitted light from the fluorescent lamp is passing through an APO-RADOGON- D lens system from Rodenstock over a mirror to the sensor. By the projection the original pixel size of 13yum in the sensor is changed to 12um in the scanned image. 3. GEOMETRIC ACCURACY If the digital images shall not be used just for orthophoto production, the loss of accuracy caused by the scanning is important. The geometric quality of the scanner should correspond to analytical plotters, it has the same meaning to the data acquisition. The geometric accuracy should not be mixed with the pixel size because a subpixel standard deviation can be reached. If the image target has a size of one pixel, by theory the location is defined with +0.3 pixel, but usually the elements are defined by a higher number of pixels. Well defined, targeted points can be measured with up to 40.02 pixels (Bósemann, Jacobsen 1995). The basic construction of the RM1 is corresponding to an analytical plotter, but there are few additional error sources because opposite to the analytical plotter the image coordinates are not just determined for a point, a line of pixels is scanned at the same time. The lack of flatness of the photo on the photo carrier has only an influence corresponding to the view direction of the sensor line. the center part of the sensor is used, in maximum the inclination of the imaging ray is corresponding to 6.144mm / 150mm = 1:24. That means, a lack of flatness of the photo of 0.1mm is causing a 4 um dislocation in maximum, in the linear mean 2pm. The geometric effect of the sensor line itself is negligible, it is far below 1um. The measuring system is based on servos together with a glass scale from RSF Elektronik. A resolution of 0.5um is reached and the used type MSA6707 shall have an accuracy of +/-3um. The x- and the y-axis should be orthogonal, this has to be calibrated. Finally we do have the same problem like in analytical plotters. Usually an error in affinity and angular affinity is unimportant because it is eliminated by the inner orientation which has the be done at least by affinity transformation in relation to the fiducial marks because of affine errors of the original photos. The location of the sensor line in the image has to be calibrated. The swath width shall correspond to the distance between the neighbored scan lines and the sensor line shall be orthogonal to the scan direction (see figure 2). The RM1 has been checked by means of 2 different reseau platen, one from the Rollei Reseau Scanner with 121e121 reseau crosses with a spacing of 2mm and one with 11e11 lines with a grid spacing of 12.5mm. For both platen the calibrated grid coordinates are available with an accuracy < + 1um. The platen have been rotated slightly against the instrument axis to avoid the check of only few rows and columns. At first the reseau cross positions in the scanned images have been measured manually with a pointing error of +2um, later on this has been done by correlation with an accuracy «1pm. The discrepancy between the measured and transformed grid coordinates to the calibrated values have been analyzed for random and systematic errors. The separation of the systematic errors can be made in the same way like the self calibration in bundle block adjustment. Additional unknowns which are able to compensate the typical geometric problems have to be introduced. <> *— | swath width misclosure in y-direction [e — = sensor line | v p gap between neighbored scans Figure 2: location of CCD- lines of neighbored scans, errors of mechanical sensor calibration sensor line not orthogonal International Archives of Photogrammetry and Remote Sensing. Vol. XXXI, Part B1. Vienna 1996

Access restriction

Copyright

fullscreen: XVIIIth Congress (Part B1)

Multivolume work

Volume

Chapter

Table of contents

Cite and reuse

Volume

Chapter

Image

Image fragment

Citation links

Citation recommendation