Ian Dowman - Academia.edu (original) (raw)
Papers by Ian Dowman
These mandatory guidelines are provided for preparation of papers accepted for publication in the... more These mandatory guidelines are provided for preparation of papers accepted for publication in the series of Volumes of The International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences from ISPRS Congresses and Symposia, and other ISPRS sponsored meetings. These guidelines are issued to ensure a uniform style throughout the series. Your cooperation in adhering to these guidelines is greatly appreciated by the host organizing committee of the meeting. The
ISPRS Journal of Photogrammetry and Remote Sensing, 2016
ISPRS Journal of Photogrammetry and Remote Sensing, 2015
Third International Conference on Remote Sensing and Geoinformation of the Environment (RSCy2015), 2015
ABSTRACT
This paper describes a new model developed at UCL for along track stereo sensors. The model is te... more This paper describes a new model developed at UCL for along track stereo sensors. The model is tested on SPOT HRS data provided under the SPOT Assessment Project (SAP) set up by CNES and ISPRS. The SPOT HRS data has been used to test a new sensor model for along track satellite data, and to generate a DEM using the Leica Photogrammetry Suite (LPS). The model described in this paper uses the collinearity equations in combination with astrodynamics. The main and fundamental point during the development of this model was to benefit from acquisition in the same orbit. The collinearity equations are modified to model the characteristics of a pushbroom scanner and the number of exterior orientation parameters. The state vector at the origin point of each image is computed. The results of testing the model with HRS data show that the model provides a stable, accurate and rigorous solution. The solution for the orientation from the LPS gives similar results to the new model and generates a ...
The Photogrammetric Record, Oct 1, 1991
Integrating Photogrammetric Techniques With Scene Analysis and Machine Vision Ii, Jul 1, 1995
International Archives of Photogrammetry and Remote Sensing Xxxv Pp 90 100, 2004
... Data fusion can be used for many applications. ... Some examples of how DEM data from LiDAR o... more ... Data fusion can be used for many applications. ... Some examples of how DEM data from LiDAR or IfSAR can be combined with other imagery or map data for feature ... Honikel (2002) shows how ERS If SAR and SPOT DEMs can be fused and develops a theory for this; Csanyi and ...
Photogramm Rec, 2006
Acquisition, validation, simulation and calibration. I. J. Dowman. The performance of correlation... more Acquisition, validation, simulation and calibration. I. J. Dowman. The performance of correlation systems. K. Green. Agrispine: a demonstration of the rapid dissemination of remote sensing data. S. Rotheram. Models of SAR sea imaging.
Bulletin Societe Francaise De Photogrammetrie Et De Teledetection, 1991
Photogrammetric Engineering and Remote Sensing, 2008
pmike, idowman)@ge.ucl.ac.uk Commision I, WG I/5
International Archives of Photogrammetry and Remote Sensing 32, 1999
The need for automation in the registration of image to image and image to map is widely recognis... more The need for automation in the registration of image to image and image to map is widely recognised and work has been going on for some time in both the photogrammetric and remote sensing disciplines. The image to image registration problem is some way to being solved for images from the same or similar sensors but there are considerable problems if the resolution of the images are different or if optical and microwave sensors are involved. Strategies are needed which will identify common features in images with different pixel size or radiometry and without dependency on initial orientation.
As the National Mapping Agency of Great Britain, the Ordnance Survey" ( 0 s ) is driven by a need... more As the National Mapping Agency of Great Britain, the Ordnance Survey" ( 0 s ) is driven by a need to reduce costs and commercialize operations, and as such has been investigating photogrammetric methods to improve existing products, streamline existing production, and increase the current portfolio of products. Over the last 18 months, the 0s has been involved in a major research project to tackle these issues through an evaluation of the forthcoming commercial U.S. high spatial resolution satellite sensors which are offering 1-m panchromatic and 4-m multispectral spatial resolutions. Work has focused on improving the existing National Height Dataset (NHD), reducing the cost of photogrammetric survey, automatic topographic feature change detection, production of DM; three-dimensional (30) urban models, and land-use classification. Results from the project using simulated imagery indicate that it would have potential within the 0s in all areas evaluated. The work now needs to be followed up when real high spatial resolution satellite imagery becomes commercially available.
![Research paper thumbnail of Geoinformation—Remote Sensing, Photogrammetry and Geographic Information Systems. By GOTTFRIED KONECNY. (London: Taylor and Francis, 2002). [Pp. xi+248]. ISBN: 0-415-23795-5. Price £19.99. Paperback](https://attachments.academia-assets.com/48359141/thumbnails/1.jpg)
](Http Dx Doi Org 10 1080 1365881031001592953, Oct 6, 2011
Integrating Photogrammetric Techniques With Scene Analysis and Machine Vision, Sep 1, 1993
It has long been known that by combining multi-source or multi-temporal Earth observation images,... more It has long been known that by combining multi-source or multi-temporal Earth observation images, the ability to detect and recognise features on the ground is greatly increased. In some specific cases models have been successfully developed for automatically integrating images from different sensors, but in general the problem of fully automatic data integration has not yet been solved. This paper introduces a new approach to automatic feature based image registration, based on multiple feature extraction and matching techniques, in order to solve the problem of automatic registration of SAR and SPOT imagery. Application of this model to pairs of small images showed that a substantial number of tie points could be found. Using these tie points with a first order transformation function consistently gave a RMS residual of less than two pixels. The model was also applied to full scene images. A method of processing based on tiling was used, rather than one based on image pyramids, since this was found to be computationally more efficient. Results showed that a large number of tie points could be located across the images. Close inspection of the matched features revealed that there were no blunders and hence the feature extraction and matching algorithm was successful.
Unspecified, 2000
There are an increasing number of sensors capable of delivering high resolution image data in a v... more There are an increasing number of sensors capable of delivering high resolution image data in a variety of spectral bands and polarisations. In addition new data sources such as LIDAR are available. The availability of this multi-sensor data offers great potential for new techniques and new products but also makes it necessary that automatic methods are used to register the data, to extract features and for change detection. This paper will review the data available and the potential of data fusion. This will include high resolution satellite data (IKONOS), airborne multispectral data, airborne LIDAR and SAR. It will also review methods of feature extraction with emphasis on building an urban landscape model using automatic classification of features according to thier size and construction. Research into feature extraction carried out at University College London will be described. Three dimensional features can be extracted with the use of image matching and generation of high density digital elevation models. If these are combined with existing map data, building elevations can be determined and changes can be identified. The additional use of multispectral data allows discrimination between buildings and trees and this process can be further aided with the use of airborne interferometric SAR and LIDAR.
These mandatory guidelines are provided for preparation of papers accepted for publication in the... more These mandatory guidelines are provided for preparation of papers accepted for publication in the series of Volumes of The International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences from ISPRS Congresses and Symposia, and other ISPRS sponsored meetings. These guidelines are issued to ensure a uniform style throughout the series. Your cooperation in adhering to these guidelines is greatly appreciated by the host organizing committee of the meeting. The
ISPRS Journal of Photogrammetry and Remote Sensing, 2016
ISPRS Journal of Photogrammetry and Remote Sensing, 2015
Third International Conference on Remote Sensing and Geoinformation of the Environment (RSCy2015), 2015
ABSTRACT
This paper describes a new model developed at UCL for along track stereo sensors. The model is te... more This paper describes a new model developed at UCL for along track stereo sensors. The model is tested on SPOT HRS data provided under the SPOT Assessment Project (SAP) set up by CNES and ISPRS. The SPOT HRS data has been used to test a new sensor model for along track satellite data, and to generate a DEM using the Leica Photogrammetry Suite (LPS). The model described in this paper uses the collinearity equations in combination with astrodynamics. The main and fundamental point during the development of this model was to benefit from acquisition in the same orbit. The collinearity equations are modified to model the characteristics of a pushbroom scanner and the number of exterior orientation parameters. The state vector at the origin point of each image is computed. The results of testing the model with HRS data show that the model provides a stable, accurate and rigorous solution. The solution for the orientation from the LPS gives similar results to the new model and generates a ...
The Photogrammetric Record, Oct 1, 1991
Integrating Photogrammetric Techniques With Scene Analysis and Machine Vision Ii, Jul 1, 1995
International Archives of Photogrammetry and Remote Sensing Xxxv Pp 90 100, 2004
... Data fusion can be used for many applications. ... Some examples of how DEM data from LiDAR o... more ... Data fusion can be used for many applications. ... Some examples of how DEM data from LiDAR or IfSAR can be combined with other imagery or map data for feature ... Honikel (2002) shows how ERS If SAR and SPOT DEMs can be fused and develops a theory for this; Csanyi and ...
Photogramm Rec, 2006
Acquisition, validation, simulation and calibration. I. J. Dowman. The performance of correlation... more Acquisition, validation, simulation and calibration. I. J. Dowman. The performance of correlation systems. K. Green. Agrispine: a demonstration of the rapid dissemination of remote sensing data. S. Rotheram. Models of SAR sea imaging.
Bulletin Societe Francaise De Photogrammetrie Et De Teledetection, 1991
Photogrammetric Engineering and Remote Sensing, 2008
pmike, idowman)@ge.ucl.ac.uk Commision I, WG I/5
International Archives of Photogrammetry and Remote Sensing 32, 1999
The need for automation in the registration of image to image and image to map is widely recognis... more The need for automation in the registration of image to image and image to map is widely recognised and work has been going on for some time in both the photogrammetric and remote sensing disciplines. The image to image registration problem is some way to being solved for images from the same or similar sensors but there are considerable problems if the resolution of the images are different or if optical and microwave sensors are involved. Strategies are needed which will identify common features in images with different pixel size or radiometry and without dependency on initial orientation.
As the National Mapping Agency of Great Britain, the Ordnance Survey" ( 0 s ) is driven by a need... more As the National Mapping Agency of Great Britain, the Ordnance Survey" ( 0 s ) is driven by a need to reduce costs and commercialize operations, and as such has been investigating photogrammetric methods to improve existing products, streamline existing production, and increase the current portfolio of products. Over the last 18 months, the 0s has been involved in a major research project to tackle these issues through an evaluation of the forthcoming commercial U.S. high spatial resolution satellite sensors which are offering 1-m panchromatic and 4-m multispectral spatial resolutions. Work has focused on improving the existing National Height Dataset (NHD), reducing the cost of photogrammetric survey, automatic topographic feature change detection, production of DM; three-dimensional (30) urban models, and land-use classification. Results from the project using simulated imagery indicate that it would have potential within the 0s in all areas evaluated. The work now needs to be followed up when real high spatial resolution satellite imagery becomes commercially available.
Http Dx Doi Org 10 1080 1365881031001592953, Oct 6, 2011
Integrating Photogrammetric Techniques With Scene Analysis and Machine Vision, Sep 1, 1993
It has long been known that by combining multi-source or multi-temporal Earth observation images,... more It has long been known that by combining multi-source or multi-temporal Earth observation images, the ability to detect and recognise features on the ground is greatly increased. In some specific cases models have been successfully developed for automatically integrating images from different sensors, but in general the problem of fully automatic data integration has not yet been solved. This paper introduces a new approach to automatic feature based image registration, based on multiple feature extraction and matching techniques, in order to solve the problem of automatic registration of SAR and SPOT imagery. Application of this model to pairs of small images showed that a substantial number of tie points could be found. Using these tie points with a first order transformation function consistently gave a RMS residual of less than two pixels. The model was also applied to full scene images. A method of processing based on tiling was used, rather than one based on image pyramids, since this was found to be computationally more efficient. Results showed that a large number of tie points could be located across the images. Close inspection of the matched features revealed that there were no blunders and hence the feature extraction and matching algorithm was successful.
Unspecified, 2000
There are an increasing number of sensors capable of delivering high resolution image data in a v... more There are an increasing number of sensors capable of delivering high resolution image data in a variety of spectral bands and polarisations. In addition new data sources such as LIDAR are available. The availability of this multi-sensor data offers great potential for new techniques and new products but also makes it necessary that automatic methods are used to register the data, to extract features and for change detection. This paper will review the data available and the potential of data fusion. This will include high resolution satellite data (IKONOS), airborne multispectral data, airborne LIDAR and SAR. It will also review methods of feature extraction with emphasis on building an urban landscape model using automatic classification of features according to thier size and construction. Research into feature extraction carried out at University College London will be described. Three dimensional features can be extracted with the use of image matching and generation of high density digital elevation models. If these are combined with existing map data, building elevations can be determined and changes can be identified. The additional use of multispectral data allows discrimination between buildings and trees and this process can be further aided with the use of airborne interferometric SAR and LIDAR.