ID: 51337
Title: Environmental Monitoring Programme on Water Quality - Report
Author: Dr. P.S.Harikumar and Dr Kamalakshan Kokkal
Editor: Dr.G.Muraleedhara Kurup
Year: 2009
Publisher: Kerala State Council for Science, Technology and Environment
Source: Centre for Ecological Science,Indian Institute of Science, Bangalore-12
Reference: None
Subject: Environmental Monitoring Programme on Water Quality - Report
Keywords: None
Abstract: None
Location: 215
Literature cited 1: None
Literature cited 2: None
ID: 51336
Title: A hybrid measurement approch for close-range photogrammetry
Author: Clive S. Fraser, Simon Cronk
Editor: George Vosselman
Year: 2009
Publisher: Elsevier, Vol 64- issue 3, May 2009
Source: Centre for Ecological Science,Indian Institute of Science, Bangalore-12
Reference: None
Subject: ISPRS Journal of Photogrammetry and Remote Sensing
Keywords: Automation, Camera calibration, Colour image scanning, Point correspondence determination, Red retroreflective targeting
Abstract: Full automation in close-range photogrammetric measurement has long been a practical reality. However, constraints apply to the process such that automated 3D measurement is generally confined to targeted points in an environment of controlled illumination. The ready availability of consumer-grade digital cameras has made photogrammetric measurement accessible and more widely employed for a host of new applications, the majority of which call for 3D measurement of other than signalized object features. Process automation is therefore typically precluded. This paper discusses a hybrid measurement approach which involves fully automatic network orientaion with targets, while at the same time supporting follow-up semi-automatic and manual operations such as feature point and line extraction and surface measurement via image matching. The topics discussed include camera calibration, the metric exploitation of colour attributes, issues related to image point correspondence determination, operator assisted feature measurement and surface extraction. All are important to the practical realisation of the hybrid measurement approach.
Location: 231
Literature cited 1: None
Literature cited 2: None
ID: 51335
Title: New developments with design and construction of a thermal/vacuum qualified photogrammetric system
Author: Jafar Amiri Parian, Alessandro Cozzani, Matteo Appolloni, Gianluca Casarosa
Editor: George Vosselman
Year: 2009
Publisher: Elsevier, Vol 64- issue 3, May 2009
Source: Centre for Ecological Science,Indian Institute of Science, Bangalore-12
Reference: None
Subject: ISPRS Journal of Photogrammetry and Remote Sensing
Keywords: Photogrammetry, Space, Accuracy, Design, Development
Abstract: In the frame of the development of a photogrammetric system to be used in thermal/vacuum chambers at the European Space Research and Technology Centre (ESTEC) of European Space Agency (ESA) and other sites across Europe, the design of a network using micro-cameras was specified by ESA-ESTEC. A thermal/vacuum qualified photogrammetric system, which is able to work and acquire images in vacuum and at cryo-temperature, was constructed by ESA-ESTEC Test Centre Division. The current system uses four space qualified one -mega pixel cameras and is able to measure large space structures in vacuum and at temperatures down to - 170oC with a global accuracy better than 1 part per 100,000 in object space. Several tests aiming at the qualification of the sensors and system in terms of operation and accuracy have been carried out. Special measures have been developed and special attention has been taken into account specifically for the first application of the photogrammetric system. It is to verify the ESA ' s Herschel Telescope Flight Model alignment positioning.
Location: 231
Literature cited 1: None
Literature cited 2: None
ID: 51334
Title: An automatic procedure for co-registration of terrestrial laser scanners and digital cameras
Author: Diego Gonzalez-Aguilera, Pablo Rodriguez-Gonzalvez, Javier Gomez-Lahoz
Editor: George Vosselman
Year: 2009
Publisher: Elsevier, Vol 64- issue 3, May 2009
Source: Centre for Ecological Science,Indian Institute of Science, Bangalore-12
Reference: None
Subject: ISPRS Journal of Photogrammetry and Remote Sensing
Keywords: Image analysis, Laserscanning, Close-range photogrammetry, Sensor fusion, Software development
Abstract: Driven by progress in sensor technology, algorithms and data processing capabilities, close range photogrammetry has found a wide range of new application fields over the past two decades. Particularly, the emergence of terrestrial laser scanner has contributed to the close range photogrammetry "popularization" through many promising new applications. Nevertheless, a central issue in many of these developments is the integration of sensor technology with reliable data processing schemes to generate highly automated photogrammetric measurements systems. This paper presents a flexible approach for the automatic co-registration of terrestrial laser scanners (TLS) and amateur digital cameras (DC) to be used effectively in practice. Particularly, the developed approach deals with two different images: a camera image acquired with a DC and a range image obtained with a TLS. To this end, an open-source tool "USAlign" has been developed for testing the different experiments.
Location: 231
Literature cited 1: None
Literature cited 2: None
ID: 51333
Title: An image engineering system for the inspection of transparent construction materials
Author: S.Hinz, M.Stephani, L.Schiemann, K.Zeller
Editor: George Vosselman
Year: 2009
Publisher: Elsevier, Vol 64- issue 3, May 2009
Source: Centre for Ecological Science,Indian Institute of Science, Bangalore-12
Reference: None
Subject: ISPRS Journal of Photogrammetry and Remote Sensing
Keywords: ETFE-foils, Close-range photogrammetry, Shape reconstruction, Shape monitoring, Bursting test
Abstract: This article presents a modular photogrammetric recording and image analysis system for inspecting the material characteristics of transparent foils, in particular Ethylen-TetraFluorEthylen-Copolymer (ETFE) foils. The foils are put under increasing air pressure and are observed by a stereo camera system. Determining the time-variable 3D shape of transparent material imposes a number of challenges; especially the automatic point transfer between stereo images and in temporal domain, from one image pair to the next. We developed an automatic approach that accommodates for these particular circumstances and allows reconstruction of the 3D shape for each epoch as well as determining 3D translation vectors between epochs by feature tracking. Examples including numerical results and accuracy measures prove the applicability of the system.
Location: 231
Literature cited 1: None
Literature cited 2: None
ID: 51332
Title: Crack measurement: Development, testing and applications of an automatic image-based algorithm
Author: Luigi Barazzetti, Marco Scaioni
Editor: George Vosselman
Year: 2009
Publisher: Elsevier, Vol 64- issue 3, May 2009
Source: Centre for Ecological Science,Indian Institute of Science, Bangalore-12
Reference: None
Subject: ISPRS Journal of Photogrammetry and Remote Sensing
Keywords: Metrology, Measurement, Matching, Close-range photogrammetry,Target recognition
Abstract: The paper presents an Image-based Method for Crack Analysis (IMCA) which is capable of processing a sequence of digital imagery to perform a twofold task; (i) the extraction of crack borders and the evaluation of its width across the longitudinal profile; (ii) the measurement of crack deformations (width, sliding and rotation). Here both problems are solved in 2-D, but an extension to 3-D is also addressed.The equipment needed to apply the method is made up of a digital camera ( or a still video-camera in case a high frequency in data acquisition is necessary), an orientation frame which establishes the object reference system, a pair of signalized supports to be placed in a permanent way on both sides of the crack to compute deformations; however, permanent targets are mandatory only for case (ii). The measurement process is carried out in a fully automatic way, a fact also that makes this technique highly operational for unskilled people in engineering surveying or photogrammetry. The accuracy of the proposed method, evaluated in experimental tests adopting different consumer digital cameras, is about + 5-20 ?m, like the accuracy of most deformometers, but with the advantage of automation and of augmented achievable information; moreover, the image sequence can be archived and off-line measurements could be performed at any time.
Location: 231
Literature cited 1: None
Literature cited 2: None
ID: 51331
Title: Precision potential of photogrammetric 6DOF pose estimation with a single camera
Author: Thomas Luhmann
Editor: George Vosselman
Year: 2009
Publisher: Elsevier, Vol 64- issue 3, May 2009
Source: Centre for Ecological Science,Indian Institute of Science, Bangalore-12
Reference: None
Subject: ISPRS Journal of Photogrammetry and Remote Sensing
Keywords: Photogrammetry, Accuracy, Precision, Close Range, 6DOF
Abstract: The article discusses the theoretical precision for the measurement of six degrees of freedom (6DOF = position and orientation in 3D space) of an object with respect to a reference system using one camera only. Single camera solutions are of interest in applications where the application is restricted to only one camera, e.g. due restrictions in terms of costs, synchronisation demands, or spatial observation conditions. A pure photogrammetric approach is discussed in which two sequential space resections generate the required six transformation values. The paper describes the mathematical model and precision evluations based on mathematical simulations and some practical examples as well. With suitable configurations of camera position, object size and reference system, accuracies of better than 1:10,000 of the measuring volume can be achieved whereby translations in Z and rotations around ? and ? are the most critical to measure.
Location: 231
Literature cited 1: None
Literature cited 2: None
ID: 51330
Title: Close-range constrained image sequences
Author: Jussi Heikkinen
Editor: George Vosselman
Year: 2009
Publisher: Elsevier, Vol 64- issue 3, May 2009
Source: Centre for Ecological Science,Indian Institute of Science, Bangalore-12
Reference: None
Subject: ISPRS Journal of Photogrammetry and Remote Sensing
Keywords: Orientation, Bundle block adjustment, Close-range,Image sequences
Abstract: This paper deals with a novel imaging arrangement for special modeling purpose. The method introduced here will take care of the geometrical consistence of photography. It is based on image ray bundles and is meant for conditions where imaging is accomplished inside the object space (e.g. in case of interior model reconstruction). Imaging is designed to be constrained in terms of camera position and orientation and to consist of two image sequences. The image orientations will be resolved by use of LSQ-estimation in heavily overdetermined conditions. The benefits of overdetermination are discussed and the accuracy assessment in a real experiment is published. The accuracy assessment is accomplished with help of exterior reference and stochastic error propagation.
Location: 231
Literature cited 1: None
Literature cited 2: None
ID: 51329
Title: Validation of geometric models for fisheye lenses
Author: D.Schneider, E. Schwalbe, H.-G.Maas
Editor: George Vosselman
Year: 2009
Publisher: Elsevier, Vol 64- issue 3, May 2009
Source: Centre for Ecological Science,Indian Institute of Science, Bangalore-12
Reference: None
Subject: ISPRS Journal of Photogrammetry and Remote Sensing
Keywords: Fisheye lens, Geometric modelling, Calibration, Bundle adjustment
Abstract: The paper focuses on the photogrammetric investigation of geometric models for different types of optical fisheye constructions (equidistant, equisolid-angle, sterographic and orthographic projection). These models were implemented and thoroughly tested in a spatial resection and a self-calibrating bundle adjustment. For this purpose, fisheye images were taken with a Nikkor 8 mm fisheye lens on a Kodak DSC 14n Pro digital camera in a hemispherical calibration room. Both, the spatial resection and the bundle adjustment resulted in a standard deviation of unit weight of 1/10 pixel with a suitable set of simultaneous calibration parameters introduced into the camera model. The camera-lens combination was treated with all of the four basic models mentioned above. Using the same set of additional lens distortion parameters, the differences between the models can largely be compensated, delivering almost the same precision parameters. The relative object space precision obtained from the bundle adjustment was ca. 1:10 000 of the object dimensions. This value can be considered as a very satisfying result, as fisheye images generally have a lower geometric resolution as a consequence of their large field of view and also have a inferior imaging quality in comparison to most central perspective lenses.
Location: 231
Literature cited 1: None
Literature cited 2: None
ID: 51328
Title: Evaluation of the geometric stability and the accuracy potential of digital cameras - Comparing mechanical stabilisation versus parameterisation
Author: D.Rieke-Zapp, W.Tecklenburg, J.Peipe, H.Hastedt, Claudia Haig
Editor: George Vosselman
Year: 2009
Publisher: Elsevier, Vol 64- issue 3, May 2009
Source: Centre for Ecological Science,Indian Institute of Science, Bangalore-12
Reference: None
Subject: ISPRS Journal of Photogrammetry and Remote Sensing
Keywords: Geometric stability, Camera calibration, Accuracy assessment, Digital camera
Abstract: Recent tests on the geometric stability of several digital cameras that were not designed for photogrammetric applications have shown that the accomplished accuracies in object space are either limited or that the accuracy potential is not exploited to the fullesst extent. A total of 72 calibrations were calculated with four different software products for eleven digital camera models with different hardware setups, some with mechanical fixation of one or more parts. The calibration procedure was chosen in accord to a German guideline for evaluation of optical 3D measuring systems [VDI/VDE, VDI/VDE 2634 Part 1, 2002. Optical 3D Measuring Systems - Imaging Systems with Point-by-point Probing. Beuth Verlag, Berlin]. All images were taken with ringflashes which was considered a standard method for close-range photogrammetry. In cases where the flash was mounted to the lens, the force exerted on the lens tube and the camera mount greatly reduced the accomplished accuracy. Mounting the ringflash to the camera instead resulted in a large improvement of accuracy in object space. For standard calibration best accuracies in object space were accomplished with a Canon EOS 5D and a 35 mm Canon lens where the focusing tube was fixed with epoxy (47 ?m maximum absolute length measurement error in object space). The fixation of the Canon lens was fairly easy and inexpensive resulting in a sevenfold increase in accuracy compared with the same lens type without modification. A similar accuracy was accomplished with a Nikon D3 when mounting the ringflash to the camera instead of the lens (52 ?m maximum absolute length measurement error in object space). Parameterisation of geometric instabilities by introducing of an image variant interior orientation in the calibration process improved results for most cameras. In this case, a modified Alpa 12 WA yielded the best results (29 ?m maximum absolute length measurement error in object space).Extending the parameter model with FiBun software to model not only an image variant interior orientation, but also deformations in the sensor domain of the cameras, showed significant improvements only for a small group of cameras. The Nikon D3 camera yielded the best overall accuracy (25 ?m maximum absolute length measurement error in object space) with this calibration procedure indicating at the same time the presence of image invariant error in the sensor domain. Overall, calibration results showed that digital cameras can be applied for an accurate photogrammetric survey and that only a little effort was sufficient to greatly improve the accuracy potential of digital cameras.
Location: 231
Literature cited 1: None
Literature cited 2: None
ID: 51327
Title: Radiometric Normalization of SPOT-5 Scenes: 6S Atmospheric Model versus Pseudo-invariant Features
Author: Aurelie Davranche, Gaetan Lefebvre and Brigitte Poulin
Editor: Russell G.Conalton
Year: 2009
Publisher: ASPRS, Vol 75, No 6, June 2009
Source: Centre for Ecological Science,Indian Institute of Science, Bangalore-12
Reference: None
Subject: Photogrammetric Engineering and Remote Sensing
Keywords: SPOT-5, 6S atmospheric model, PIFs,
Abstract: We compared the efficiency and robustness of two radiometric correction techniques applied to six SPOT-5 scenes used for assessing environmental changes of Camargue wetlands: the 6S atmospheric model and 86 pseudo-invariant features (PIFs) found in deep water, pine trees, roofs and sand. The few PIFs were selected subjectively following the low number of potentially invariant sectors available on the scenes. Both approaches provided a similar radiometric variation (6S = 4.3 percent; PIFs = 4.0 percent). The latter increased from water to pine trees, to roofs and sand, with five reference points per feature being identified as cost effective. The withdrawing of variant features among the PIFs across dates or points caused a singificant decrease in radiometric variation, especially with 6S (6S = 2.8 percent, PIFs = 3.4 percent). As many as 31 point per type of PIFs would be necessary to provide a radiometric variation that is not significantly different from that obtained with 6S, whereas nearly 300 and 4,000 points per feature would be required to provide similar or better results than the 6S code, respectively. Use of a few PIFs remains a valid approach, as long as the invariant sectors cover a wide range of brightness and are represented by objects of which the radiometric variation has preliminarily been tested.
Location: 231
Literature cited 1: None
Literature cited 2: None
ID: 51326
Title: Isomorphism in Digital Elevation Models and Its Implication to Interpolation Functions
Author: Peng Hu, Xiaohang Liu and Hai Hu
Editor: Russell G.Conalton
Year: 2009
Publisher: ASPRS, Vol 75, No 6, June 2009
Source: Centre for Ecological Science,Indian Institute of Science, Bangalore-12
Reference: None
Subject: Photogrammetric Engineering and Remote Sensing
Keywords: DEM, Group theory, TIN, 1D
Abstract: Terrain is an ordered surface where locations relate to each other through their elevations. Preservation of this topographic orderliness by an interpolation method so that "if point A is higher than point B in the terrain, the interpolated elevation of A remains higher" is important to assure the practical value of the resultant DEM. Based on the concepts in group theory, this paper points out that a DEM must be isomorphic to terrain surface in order to preserve the topographic orderliness. Such a DEM, if generated through interpolation, can only be obtained if the interpolation function is an isomorphism. Two necessary conditions for isomorphism are identified: a one-to-one relationship between the topographic surface and the surface corresponding to the interpolation function and the feasibility to configure the topographic surface into monotonic patches during interpolation. The isomorphism of three widely used interpolation methods is examined. It is found that linear interpolation in 1D and TIN are both isomorphisms, meaning that a DEM interpolated by either method can preserve the topographic orderliness. In contrast, bilinear interpolation is not as isomorphism. Considering the practical challenges in assuring the necessary conditions of isomorphism in each method, linear interpolation in 1D is recommended as the optimal method to interpolate a DEM.
Location: 231
Literature cited 1: None
Literature cited 2: None
ID: 51325
Title: Occlusion-based Methodology for the Classification of Lidar Data
Author: Ayman F.Habib, Yu-Chuan and Dong Cheon Lee
Editor: Russell G.Conalton
Year: 2009
Publisher: ASPRS, Vol 75, No 6, June 2009
Source: Centre for Ecological Science,Indian Institute of Science, Bangalore-12
Reference: None
Subject: Photogrammetric Engineering and Remote Sensing
Keywords: Lidar, Digital Surface Model
Abstract: Lidar systems have been widely adopted for the acquistion of dense and accurate topographic data over extended areas. The level of detail and the quality of the collected point cloud motivated the research community to investigate the possibility of automatic object extraction from such data. Prior knowledge of the terrain surface will improve the performance of object detection and extraction procedures. In this paper, a new strategy for automatic terrain extraction from lidar data is presented. The proposed strategy is based on the fact that sudden elevation changes, which usually correspond to non-ground objects, will cause relief displacements in perspective views. The introduced relief displacements will occlude neighboring ground points. To start the process, we generate a digital surface model (DSM) from the irregular lidar points using an interpolation procedure.The presence of sudden-elevation changes and the resulting occlusions can be discerned by sequentially checking the off-nadir angles to the lines of sight connecting the DSM cells and a pre-defined set of synthesized projection centers. Detection occlusions are then used to identify the occluding points, which are hypothesized to be non-ground points. Surface roughness and discontinuities together with inherent noise in the point cloud will lead to some false hypotheses.Therefore, we use a statistical filter to remove these false hypotheses. The performance of the algorithm has been evaluated and verified using both simulated and real lidar datasets with varying levels of complexity.
Location: 231
Literature cited 1: None
Literature cited 2: None
ID: 51324
Title: Meta-Prediction of Bromus tectorum Invasion in Central Utah, United States
Author: Nicholas Etienne Clinton, Peng Gong, Zhenyu Jin, Bing Xu and Zhiliang Zhu
Editor: Russell G.Congalton
Year: 2009
Publisher: ASPRS, Vol 75, No 6, June 2009
Source: Centre for Ecological Science,Indian Institute of Science, Bangalore-12
Reference: None
Subject: Photogrammetric Engineering and Remote Sensing
Keywords: Cheatgrass, Landsat TM, PACE regression
Abstract: Cheatgrass (Bromus tectorum) is an invasive, exotic grass infesting the Western US. Multi-temporal Landsat TM imagery and ancillary topographic data were used for mapping this invasion over portions of Utah. Tobit, logit, probit and Projection Adjustment by Contribution Estimation (PACE) regression, neural networks and additive regression of regression trees were tested individually and in an ensemble, Tobit regression had the best performance as an individual predictor. Tobit was most frequently the best predictor of zero cheatgrass coverage. A meta-predictor (classifier) to choose the best predictive model was implemented on a pixel-by-pixel basis. A J48 classification tree as a meta-predictor resulted in an increase in accuracy over the best performer in the ensemble. This study illustrated the potential for meta-prediction as a general technique for increasing accuracy from a collection of base predictors.
Location: 231
Literature cited 1: None
Literature cited 2: None
ID: 51323
Title: An Adaptive Thresholding Multiple Classifiers System for Remote Sensing Image Classification
Author: Yu-Chang Tzeng, Kou-Tai Fan and Kun-Shan Chen
Editor: Russell G.Congalton
Year: 2009
Publisher: ASPRS, Vol 75, No 6, June 2009
Source: Centre for Ecological Science,Indian Institute of Science, Bangalore-12
Reference: None
Subject: Photogrammetric Engineering and Remote Sensing
Keywords: Bagging algorithms, Boosting algorithms, SAR, adaptive thresholding criterion
Abstract: A multiple classifiers system which adopts an effective weighting policy to combine the output of several classifiers, generally leads to a better performance in image classificaion. The two most commonly used weighting policies are Bagging and Boosting algorithms. However, their performance is limited by high levels of ambiguity among classes. To overcome this difficulty, an adaptive thresholding criterion was proposed. By applying it to SAR and optical images for terrain cover classification, comparisons between the multiple classifiers systems using the Bagging and/or Boosting algorithms with and without the adaptive thresholding criterion were made. Experimental results showed that the classification substantially improved when the adaptive thresholding criterion was used, especially when the level of ambiguity of targets was high.
Location: 231
Literature cited 1: None
Literature cited 2: None