Proceedings International Workshop on Mobile Mapping Technology

li, rongxing

Bibliographic data

Monograph

Persistent identifier:: 856671290

Author:: Li, Rongxing

Title:: Proceedings International Workshop on Mobile Mapping Technology

Sub title:: April 21 - 23, 1999, Bangkok, Thailand

Scope:: 1 Online-Ressource (Getr. Zählung [ca. 400 Seiten])

Year of publication:: 1999

Place of publication:: London

Publisher of the original:: RICS Books

Identifier (digital):: 856671290

Illustration:: Illustrationen, Diagramme, Karten

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:: [Session 2: Mobile Mapping (2)]

Document type:: Monograph

Structure type:: Chapter

Chapter

Title:: TOWARDS AUTOMATED PROCESSING OF MOBILE MAPPING IMAGE SEQUENCES. C. Tao, M. A. Chapman, and N. El-Sheimy, B. Chaplin.

Document type:: Monograph

Structure type:: Chapter

2-5-2 The development of automated approaches to enhance the processing of mobile mapping image sequences using computational vision theories and methods has been one of the research focuses at The University of Calgary. The methods developed can be grouped into two categories: Information extraction and image bridging using stereo image sequences. These methods are described along with a discussion of the evaluation results using VISAT image data sets. 2. OVERVIEW OF MOBILE MAPPING TECHNOLOGY Mobile mapping systems represent a significant advance in multi-sensor integrated digital mapping technology, which provides an innovative path towards rapid and cost-effective collection of high-quality and up-to-date spatial information (Bossier et al., 1991; Chapman et al., 1999; El-Sheimy, 1996; Hock, et al., 1995; Li, 1997; Novak, 1995; Schwarz et al., 1993b and Tao, 1998). The development of mobile mapping systems is promoted by the use of multi-sensor integration technology. In general, we classify the sensors into three categories: (1) Absolute orientation sensors • Environment-dependent external positioning sensors: GPS, and radio navigation systems • Self-contained inertial positioning sensors: INS, dead reckoning systems, gyroscopes, accelerometers, compasses, odometers, and barometers (2) Relative orientation sensors • Passive imaging sensors: Video and digital cameras • Active imaging sensors: Laser range finders or scanners, and Radar (SAR) (3) Attribute collection sensors • Passive imaging sensors: video/digital frame cameras, multi-spectrum/hyper-spectrum push-broom scanners • Active imaging sensors: SAR and Laser range finders or scanners • Manual recording: voice recording and touch-screen recording • Other sensors: temperature, air pressure, gravity gauges, etc. A global coord. A local coord. Objects of system system interest Figure 1. The concept of direct georeferencing Absolute orientation sensors are platform-oriented. They are used to determine the absolute locations of the mobile mapping platform, for instance, a van-type vehicle, with respect to a global coordinate system (e.g., WGS-84). On the other hand, relative orientation sensors provide the positional information of objects relative to the platform in a local coordinate system. Both relative orientation sensors and attribute collection sensors are feature-oriented, and many have capabilities of providing both orientation and attribute information, such as imaging cameras and laser range finders/scanners. One of the most important concepts of mobile mapping systems is direct-georeferencing. The conceptual layout of direct georeferencing is shown in Figure 1. Direct-georeferencing refers to the use of absolute orientation sensors to determine the exterior orientation of the sensors without using ground control points and photogrammetric block triangulation. For example, if a camera sensor is used, any captured image can be “stamped” with the georeferencing parameters, namely three positional parameters and three attitude parameters by using absolute orientation sensors (GPS/INS). As a result, 3-D reconstruction using stereo images becomes straightforward, since the exterior orientation parameters of each image are available. Direct georeferencing greatly facilitates the mapping procedure. The rapid turn-around time of data processing and reduced cost of ground control surveys are very beneficial. 3. VISUAL MOTION ANALYSIS OF MOBILE MAPPING IMAGE SEQUENCES In recent years, the computer vision community has extensively addressed the computational aspects of visual motion analysis. In this section, the general methodology used in visual motion studies is reviewed. The purpose is to try to identify the problems that we have under the framework of visual motion analysis, so that the well-developed methods and the accumulated experience can be utilized. 3.1 Basic Issues in Visual Motion Analysis In principle, the study of visual motion analysis, or, motion and structure from image sequences, consists of two basic issues: • Determining image optical flow and/or feature correspondences from image sequences, and • Estimating motion and structure parameters using the determined optical flow and/or feature correspondences. In mobile mapping systems, the captured image sequences have been georeferenced by using GPS/INS integrated positioning techniques. The orientation parameters of each camera exposure center are determined with respect to a global coordinate system, i.e., the motion is known. By using techniques of photogrammetric intersection, the computation of 3-D object coordinates is very straightforward. However, conjugate points need to be identified, that is, point (feature) correspondence needs to be established. Therefore, our research emphasis will be placed on the first issue - determination of correspondences from image sequences. In fact, the photogrammetry community has been paid a great amount of attention to the second issue. The research results from computer vision studies not only enhance the understanding of projective geometry and algebraic geometry, but also extend and enrich photogrammetric theories and methods, for example, videogrammetry. Some of the concepts, theories and methods derived by computer vision groups have been investigated by photogrammetrists and applied in

Access restriction

Copyright

fullscreen: Proceedings International Workshop on Mobile Mapping Technology

Monograph

Chapter

Chapter

Table of contents

Cite and reuse

Monograph

Chapter

Image

Image fragment

Citation links

Citation recommendation