Systems for data processing, anaylsis and representation

Allam, Mosaad; Plunkett, Gordon

Bibliographic data

Monograph

Persistent identifier:: 1067490280

Title:: Systems for data processing, anaylsis and representation

Sub title:: ISPRS Commission II Symposium : June 6 - 10, Ottawa, Canada

Scope:: 1 Online-Ressource (XX, 530 Seiten)

Year of publication:: 1994

Place of publication:: Ottawa

Publisher of the original:: The Surveys, Mapping and Remote Sensing, Natural Resources Canada

Identifier (digital):: 1067490280

Illustration:: Illustrationen

Signature of the source:: ZS 312(30,2)

Language:: English

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

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

Editor:: Allam, Mosaad; Plunkett, Gordon

Corporations:: Symposium Systems for Data Processing, Analysis and Representation, 1994, Ottawa; International Society for Photogrammetry and Remote Sensing; International Society for Photogrammetry and Remote Sensing, Commission Instrumentation for Data Reduction and Analysis; Kanada, Surveys, Mapping and Remote Sensing Sector

Adapter:: Symposium Systems for Data Processing, Analysis and Representation, 1994, Ottawa; International Society for Photogrammetry and Remote Sensing; International Society for Photogrammetry and Remote Sensing, Commission Instrumentation for Data Reduction and Analysis; Kanada, Surveys, Mapping and Remote Sensing Sector

Founder of work:: Symposium Systems for Data Processing, Analysis and Representation, 1994, Ottawa; International Society for Photogrammetry and Remote Sensing; International Society for Photogrammetry and Remote Sensing, Commission Instrumentation for Data Reduction and Analysis; Kanada, Surveys, Mapping and Remote Sensing Sector

Other corporate:: Symposium Systems for Data Processing, Analysis and Representation, 1994, Ottawa; International Society for Photogrammetry and Remote Sensing; International Society for Photogrammetry and Remote Sensing, Commission Instrumentation for Data Reduction and Analysis; Kanada, Surveys, Mapping and Remote Sensing Sector

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:: Monograph

Collection:: Earth sciences

Chapter

Title:: [Wednesday, June 8, 1994]

Document type:: Monograph

Structure type:: Chapter

Chapter

Title:: [Session F-1 WG II/1 - Real-Time Mapping Technologies - Automatic Orientation of Sensors]

Document type:: Monograph

Structure type:: Chapter

Chapter

Title:: A PRECISE POSITIONING/ATTITUDE SYSTEM IN SUPPORT OF AIRBORNE REMOTE SENSING K. P. Schwarz, M. A. Chapman, M. E. Cannon, P. Gong, D. Cosandier

Document type:: Monograph

Structure type:: Chapter

accuracy of a printed map that includes these compilation errors are five to ten times higher, see for instance Merchant (1987) and Tobler (1988). Using a line accuracy of 0.25 mm and considering that typical photo scales for base maps are between 1:12 000 and 1:15 000, the positional accuracy required of objects on the ground is 2-5m to meet the high accuracy end of cartographic applications from 1:10 000 upward. In the resource sector, accuracy requirements cover a rather broad spectrum. At the high accuracy end of these applications, requirements are almost as stringent as in the engineering and cadastral applications mentioned above. Although sample plots with a size of 20 m by 20 m are standard in conventional forest inventory, substantially higher spatial resolution is required to reflect the internal variability of the sample stand. Detailed measurements for the tree diameter at breast height, canopy density, height etc. make a spatial resolution down to 0.25 m desirable, see Till et al (1987) for details. To discern and interpret individual trees implies a spatial resolution of less than 1 m. For damage assessment, a resolution of 5 m is needed. Table 1 shows a summary of the accuracies required for different application areas, expressed as root mean square errors (rms) for position and attitude. It indicates that, except for a small number of high accuracy applications which require positions at the decimeter level, an accuracy of 2-5 m is fully sufficient for the bulk of the applications. This result is important for the design of GIS data bases. Instead of mixing information from different application areas with different spatial resolution requirements, it seems advisable to require a uniform spatial resolution of 2-5 m for the standard resource data base. High accuracy applications which are usually restricted to smaller projects will normally not be part of these data bases. RMS Accuracy for Application Area Position | Attitude Engineering, Cadastral | 0.05 - 0.1 | (15" - 30") m Cartographic Mapping 1:10 000 2-5 m 10' - 20' Resource Applications 2-5m 20' - 30' Forestry (Detailed) 0.2 - 10m 1-3 Table 1: Accuracy Requirements 3. ACCURACY OF CURRENT REMOTE SENSORS The georeferencing requirements of an airborne positioning and attitude system is determined by the spatial resolution of the remote sensor. Commonly used sensors such as photographic systems, scanning and linear array systems, and synthetic aperture radar (SAR) have quantifiable spatial resolution limitations. As such the following discussion will be focused on these sensor types. 3.1 Spatial Systems Resolution of Photographic The spatial resolution (R) of an aerial photograph is influenced by a number of factors such as the resolving power of the camera lens and the film used in a photographic system. In addition, the spatial resolution is affected by any uncompensated image motion during exposure, the atmospheric conditions present at the time of image exposure, and the conditions of image processing (Lillesand and Kiefer, 1987). Also, the focal length (f) and the distance (d) between a target and the camera also determine the spatial resolution of a photograph. Among these, only the resolving power of the photographic system and the uncompensated image motion may be quantifiable. The resolving power of a photographic system is expressed in number of line-pairs/mm (n) (i.e., black and white line pairs of equal thickness (Wolf, 1974). The optical quality of the lens, the granularity and the speed of the film all contribute to the determination of the resolving power of a photographic system. Under a range of contrast of black and white between 2:1 to 1000:1, the resolving power of photographic systems ranges from 50 line pairs/mm to 100 line pairs/mm (Lillesand and Kiefer, 1987). Due to a number of other factors mentioned above, R is usually poorer than d/(fn2000) m. Thus, R > d/(fn2000) m. (1) The ratio f/d determines the local image scale (s) for the photographed target. For example, an aerial photograph with a 1:10000 image scale and a resolving power of 50 linepairs/mm, has a spatial resolution (R) which is 0.1 m or less. Consequently, the positional accuracy requirements are 10 cm while the attitude requirements correspond to 15 arcseconds for the exterior orientation of an individual photograph. In general, multiple strips of photographs are used in a block adjustment to obtain a favorable error distribution making use of the inherent geometrical strength of the photographic image. In this case, georeferencing can be done by position control only. Precise independent attitude is not needed because bundles of interlocking rays will take care of this requirement. By accurately fixing the perspective centres of these bundles in space, even high accuracy requirements can be met. 3.2 Spatial Resolution of Scanning Systems and CCD Frame Imagers Compared with a photographic system, the only influencing factor that is different in a scanning system or a CCD frame imager is that the resolving power of the film has been replaced by the size (z) of charge-coupled devices (CCDs). Since the resolving power of a camera lens is considerably higher than the size of a CCD, the determining factor becomes the size of the CCD. Similar to the photographic systems, the spatial resolution (R) for a sensor system based on CCD technology cannot be better than z/s or dz/f, i.e. R » dz/f, (2a) when f, d, and z are given. For CCD-based airborne sensors, often the physical dimension (p) of the CCD array, the number of CCD elements in a line (nc) and the camera field- of-view angle (B) are specified. Here, f can approximately be 192 obtained pta given by p/n For example, array of dim elements. W m. Increas: elements pe increased sto storage rate 1 knots and 5C disk technol CCDs have r If the aircraf is 1/250 secc without any « will degrade the flight di accuracy ve Because CCI of aerial pho for georefer systems. necessary, de application. 3.3 SAR / Synthetic-ape discussed so input in rea particular, tl accumulation aircraft is ir minimize the velocity rec overlooked tl heavily on georeferencir control and t Design speci because it commercially system inclu provide swat in the X-ban System can : orentation t resolutions o modes are 12 to seven lool modes. It is knots. The p à pulse rep: maximum Correspondir of 0.0002-0. multi-look a While positi level of 15- based upon This implies 24 m. If in:

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