Sharing and cooperation in geo-information technology

Aziz, T. Lukman

Bibliographic data

Monograph

Persistent identifier:: 856479470

Author:: Aziz, T. Lukman

Title:: Sharing and cooperation in geo-information technology

Sub title:: ISPRS Commission VI Symposium, April 15 - 17, 1999, Bandung, Indonesia

Scope:: 1 Online-Ressource (130 Seiten)

Year of publication:: 1999

Place of publication:: London

Publisher of the original:: RICS Books

Identifier (digital):: 856479470

Illustration:: Illustrationen, Diagramme

Language:: English

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

Publisher of the digital copy:: Technische Informationsbibliothek Hannover

Place of publication of the digital copy:: Hannover

Year of publication of the original:: 2016

Document type:: Monograph

Collection:: Earth sciences

Chapter

Title:: WG VI/3: INTERNATIONAL COOPERATION AND TECHNOLOGY TRANSFER

Write comment:: Der Aufsatz "Promotion Of The General Understanding And Improvement Of Public Relations, [...] ist im Original nicht enthalten.

Document type:: Monograph

Structure type:: Chapter

Chapter

Title:: AUTOMATION IN PHOTOGRAMMETRY. David Collison

Document type:: Monograph

Structure type:: Chapter

68 Table 1. Comparison the traditional optical/mechanical approach with today’s softcopy AT processes Process Optical/Mechanical Softcopy Film Process & create diapositives Process Scdn Not required Required Point marking Avg.points/model Time/model Accuracy Solution Robustness Required 6 20-30 min Operator skill dependent minimal Not required -60 (user definable) l-2min Superior and consistent Significant redundancy The relationship of AT to the aerial survey has also become very important as GPS Technology is today being widely applied during air survey missions. The introduction and success of auto AT is just starting to be felt, but the implications are enormous. By minimizing this often difficult and complex task, the doors to photogrammetry open to a vast army of potential users, especially as low cost personal computer systems can now be used for stereo collection and analysis. 4. DIGITAL TERRAIN MODELS Probably the first successful implementation of significant automation was in the DTM generation process. DTM’s are a key requirement for orthophotos and terrain analysis. When used appropriately auto DTM generation is now quite successfully applied. Generally additional geomorphological features such as break-lines, exclude areas and salient point are invaluable to the DTM surface formation process and are highly recommended. The auto DTM generation process utilizes a features based matching in a hierarchical process where refinement via least squares adjustment of the derived DTM improves as the computation proceeds down through the pyramids to the lowest level. See Figure 3. Despite high automation, post process interactive editing is generally deemed necessary for quality assurance. The amount of editing and number of geomorphological features required depends on the purpose for which the DTM is required. If contours are desired as final output then detailed collection of break lines and salient points would be required to give appropriate structure to the software generate contours. For orthophoto generation only, often little additional terrain structure is required. 5. ORTHOPHOTO The process of ortho rectification for aerial photographs can be summarised as the conversion from central perspective to orthographic projection. The conversion is undertaken generally as a batch processes in which a new output image is generated from the input image after corrections for terrain height displacement (requirement for DTM) and photo tip and tilts (requirement for At) have been applied. Once images are rectified the step of mosaicking or digitally joining one or more images may be undertaken in which several steps may be combined such as global tonal balance, seam line definition and area extraction. Generally it is desirable to minimize the number of photographs required to “make-up” an orthophoto and by using good flight planning and GPS camera control resulting in pinpoint exposures. Upon completion of the rectification and mosaic processes the orthophoto image can easily be recorded (permanently) onto compact disc (CD) for distribution and archive 6. LOOKING AHEAD There are many challenges ahead, one often talked about is automatic feature recognition which is still considered some way away from full and robust implementation, but like other steps to automation, incremental advances involving. Research into automated building extraction is well advanced as with automatic line following. The challenge is to bring these research activities into the main stream commercial systems, which can provide as good if not better solutions that current interactive techniques provide. Another area of high interest is at the airborne acquisition stage where the potential of combing inertial navigation systems (INS) and GPS could ultimately result in fully orientated photos at the moment of capture. Once this technology is refined and combined with say digital aerial cameras, it may lead to the elimination of today’s scanning and aerotriangulation steps. Small format digital cameras are already being deployed for aerial imagery capture in conjunction with GPS recording of exposure stations capturing either color or color infrared imagery. As the CCD array sizes expand we can look forward to even more utilization of these systems with metric or semi-metric cameras.

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