XVIIIth Congress: Commission VI

Kraus, Karl; Waldhäusl, Peter

Bibliographic data

Multivolume work

Persistent identifier:: 1667435949

Title:: XVIIIth Congress

Sub title:: Vienna, Austria 1996

Year of publication:: 1996

Place of publication:: Vienna

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

Identifier (digital):: 1667435949

Language:: English

Editor:: Kraus, Karl; Waldhäusl, Peter

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

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

Founder of work:: International Society for Photogrammetry and Remote Sensing, Congress, 18., 1996, Wien; International Society for Photogrammetry and Remote Sensing

Other corporate:: International Society for Photogrammetry and Remote Sensing, Congress, 18., 1996, Wien; International Society for Photogrammetry and Remote Sensing

Document type:: Multivolume work

Volume

Persistent identifier:: 1677550198

Title:: Commission VI

Scope:: 149, 110, 92 Seiten

Year of publication:: 1996

Place of publication:: Vienna

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

Identifier (digital):: 1677550198

Illustration:: Illustrationen, Diagramme

Signature of the source:: ZS 312(31,B6)

Language:: English

Additional Notes:: Die Vorlage enthält insgesamt 3 Werke: Commission VI (Seiten 1-149); National reports (Seiten 1-110); Special sessions (Seiten 1-92)

Other Title:: Enthaltendes Werk: National Reports; Enthaltendes Werk: Special sessions

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

Editor:: Kraus, Karl; Waldhäusl, Peter

Corporations:: International Society for Photogrammetry and Remote Sensing, Congress, 18., 1996, Wien; International Society for Photogrammetry and Remote Sensing; International Society for Photogrammetry and Remote Sensing, Commission Economic, Professional, and Educational Aspects of Photogrammetry and Remote Sensing

Adapter:: International Society for Photogrammetry and Remote Sensing, Congress, 18., 1996, Wien; International Society for Photogrammetry and Remote Sensing; International Society for Photogrammetry and Remote Sensing, Commission Economic, Professional, and Educational Aspects of Photogrammetry and Remote Sensing

Founder of work:: International Society for Photogrammetry and Remote Sensing, Congress, 18., 1996, Wien; International Society for Photogrammetry and Remote Sensing; International Society for Photogrammetry and Remote Sensing, Commission Economic, Professional, and Educational Aspects of Photogrammetry and Remote Sensing

Other corporate:: International Society for Photogrammetry and Remote Sensing, Congress, 18., 1996, Wien; International Society for Photogrammetry and Remote Sensing; International Society for Photogrammetry and Remote Sensing, Commission Economic, Professional, and Educational Aspects of 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:: Commission VI

Document type:: Multivolume work

Structure type:: Chapter

Chapter

Title:: LEARNING DIGITAL PHOTOGRAMMETRY BY MEANS OF PERSONAL COMPUTERS. Joachim Höhle [...] Commission VI, Working Group 2

Document type:: Multivolume work

Structure type:: Chapter

coordinate system and the principal point one transforms the measured pixel coordinates into an image coordinate system given by the calibrated values of the fiducial marks. There can be 4, 8 or more fiducial marks that have to be measured. Other marks which have to be measured as well are réseau crosses, which are positioned on a glass plate inside a special camera, called réseau camera, and which are imaged to- gether with the object. By means of these réseau crosses it is possible to detect image deformations or deficiencies of the used scanner and thereafter correct them. The mentioned marks or crosses are all well-defined, and their image matrix is known beforehand. It is called a template. By moving the template in steps of one picture element over the image one searches in the image for the imaged fiducial mark or cross. At each position of the template a correlation coefficient is calculated. The position where the correlation coefficient has its greatest value is the searched one. The accuracy of the determination is the size of one picture element. If subpixel accuracy is required, a least square adjustment has to be applied. A small shift of the template and two other parame- ters (which apply corrections in the greyvalues of the pixels) have to be calculated. This rather complex calculation leads to a positional accuracy which is about 1/10 of the pixel size. The measuring is completely automatic and fast. The réseau camera is very handy and a pretty high accuracy can be achieved. Réseau cameras and réseau techniques are successfully used in industrial applications. (Dold, J. et al., 1993). 2.2 The pedagogical concept When a theme is selected, the information about this theme (the so-called "knowledge") is presented. This occurs by means of screen images with text and figures. A text is written line by line on the screen, and additional information can be displayed when it is wanted. The attached figures are dynami- cal ones. The information is presented by small pieces so that it can be grasped. The sequence of the text lines can also be repeated. Several exercises ("tasks") are connected to the themes. The student is active and manipulates a figure or calculates values. The result of the "task" is sensed automati- cally or typed in the keyboard and immediately checked by the program. This immediate and neutral feed back is one of the main strengths of this CAL program. The user interface is graphical and very simple. There are only few fields with their icons and texts to point to. The ones at the bottom line are used for the navigation through the program, the ones on the right side for the manipulation within the displayed screen image (compare the figure). They are started by means of the mouse or the track pad. A 'help' window informs about the next steps to be taken. A simulated pocket calculator can be used for the calculation of the results. The language in the texts is English only. 2.3 The technical concept The prototype of "LDIP" uses Macintosh hardware, the models "2si" and "PowerBook 520". Both of them can be connected to a CD 300 drive in order to read imagery from a CD-ROM. The transportable PowerBook with a black and 'white screen can also be connected to a plasma screen (LCD) which enables the projection on a large screen in colour. The PowerBook can be upgraded to a PowerPC which then also makes possible the emulation of the DOS operating system so that PC programs can be used at a reasonable speed. The software is written in Think Pascal and runs under the 'System 7.1'. This operating system contains also toolboxes - with numerous functions for the development of CAL software such as pull down menus, input and message boxes, icons, image and sound facilities. THEME 1: AUTOMATIC MEASUREMENT gb OF RÉSEAU CROSSES AND FIDUCIAL MARKS SEARCH MATRIX TARGET MATRIX - THE POSITION OF THE TARGET (RÉSEAU CROSS OR FIDUCIAL MARK) SHALL BE FOUND IN THE SEARCH MATRIX - THE DENSITIES OF THE TARGET HAVE NOISE AND SMEAR THE IMAGE - THE TARGET MATRIX IS MOVED PIXEL BY PIXEL OVER t THE SEARCH MATRIX - AT EACH POSITION A CORRELATION COEFFICIENT (r) IS CALCULATED - THE POSITION WITH THE GREATEST VALUE OF r IS THE REQUIRED POSITION Information HELP P =) @ INFORMATION TASK REPEAT RETURN TO MAIN MENU STOP Fig. 2. Screen image for 'Knowledge' in the CAL program “LDIP”. At this moment of the sequence all of the text lines and the additional information is displayed. The target matrix of 5 x 5 pixels is situated within the search matrix at the position where the correlation coefficient is r=0.28. All image data shall be stored on an assembled CD-ROM which has to be produced from imagery originally stored on various media and at various formats. The image data is loaded from an attached or integrated CD-ROM drive or from various discs if CD-ROM drives are not available. 2.4 Description of the use 2.4.1 Automatic measurement of réseau crosses and fiducial marks: Five text lines for this theme are displayed sequentially, they are coordinated with the attached figure. In this dynamic figure a target matrix moves over the search matrix and the correlation coefficients are displayed at each position (see fig. 2). The grey values of the two images (search and target area) can be displayed as numbers or as shades of grey. With the field "INFORMATION" the formulas for the correlation coefficient can be displayed in addition. Also, the different parameters in the formula are then explain- ed in detail. All this information is necessary for carrying out the related exercise (task 1.1). For this purpose, the field "TASK" has to be activated. 2.4.2 Automatic measurement - task 1.1: The best fit of two density profiles (target and search area) has to be found, first manually by moving the target area over the search area. The user clicks either on the icon "RIGHT" or "LEFT", whereby the target area moves in the selected direction. At the position of best fit a correlation coefficient has to be calculated. The pocket calculator can be used for the compu- tation. If the student has forgotten the formula for the compu- tation of the correlation coefficient, the icon "KNOWLEDGE" is clicked on which leads back to the screen image with the formula. The computed value has to be typed in the keyboard and is displayed at the input window. If the result is correct, the program will indicate it by writing and saying "CORRECT!" In the other case the written and spoken answer are "WRONG!". By means of the icons "NEXT TASK" or "RE- TURN TO MAIN MENU" the student can proceed. 2.4.3 International Archives of Photogrammetry and Remote Sensing. Vol. XXXI, Part B6. Vienna 1996 Corr abou two fi repee and € on tl point Corre shifte than introc deter INFO Fig. 3 progr are di print) active 2.4.4 exerc equat set ir calcu watcl accul she L (see f and t All inp TH TA 9171 92 “NOUSU AUD 5 Fig. 4 - One deter

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fullscreen: Commission VI (Part B6)

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