Image mapping using data from visible and infrared sensors has, as a major drawback, the frequent... more Image mapping using data from visible and infrared sensors has, as a major drawback, the frequent cloud cover experienced in many countries. This is one of the main reasons why topographic maps at 1:100,000 scale and larger are often outdated. The results of a study which investigated the possibilities of fusing up-to-date spaceborne microwave data with existing images from optical sensors for topographic map updating at a scale of 1:100, 000 are presented in this paper. A key issue researched was the influence of geometric distortions and corrections of remote sensing data on the results of pixel based digital image fusion. After having terrain-geocoded and radiometrically enhanced imagery from the Landsat, SPOT, ERS-1 and JERS-1 satellites, the data were fused applying a variety of colour transformation techniques as well as statistical or arithmetic methods. Initially, the image fusion was implemented using images covering a test site in the north of The Netherlands in order to calibrate specified combinations and techniques in a rather flat area. With the experience gained, the remote sensing data acquired over the research site were processed. The research test site is located in a typical Developing Country in the humid Tropics, on the mountainous south-west coast of Sumatra in Indonesia. The results of the various applied techniques and image combinations were evaluated with reference to their capability to overcome the cloud cover problem. New combinations of techniques and images were developed as result of an optimisation process. The research produced two prototypes of annotated 1:100,000 scale image maps containing fused, cloud-free optical/microwave imagery.
2014 IEEE Conference on Biomedical Engineering and Sciences (IECBES), 2014
Ahstract-In diagnosis, planning, intervention and monitoring of the potentially fatal Coronary Ar... more Ahstract-In diagnosis, planning, intervention and monitoring of the potentially fatal Coronary Artery Dis ease multimodal medical imaging plays an important role. Medical cardiac images of patients suffering from Athero sclerosis exhibit information on cardiovascular plaque that can cause a sudden death due to its vulnerability. The identification of vulnerable plaque is an important re search field and can be supported by the use of multimodal image fusion combining anatomical as well as functional information in one image medium. Image fusion has prov en to enhance critical components of the multimodal data sources that enable improved diagnostics and intervention. The advancement of image fusion techniques and an intel ligent selection of multimodal medical image combinations in the context of vulnerable plaque detection require an interdisciplinary approach. This paper reports on the first achievements of a collaborative research project involving clinicians and image processing engineers. During the first stage an interdisciplinary workflow was established. Criti cal research questions were identified. The second phase
The high resolution remote sensing satellite Razaksat is a unique satellite system since it opera... more The high resolution remote sensing satellite Razaksat is a unique satellite system since it operates in a near-equatorial orbit with a low inclination angle of 9. In a first study scientists have found the images suitable for feature extraction in an urban context to update the road network at a scale of 1:25,000. In a preceding project for land cover mapping the research team used the five available bands of Razaksat imagery. This paper describes a continuation of the former study in which techniques are used to fuse the high resolution panchromatic band with the lower resolution multispectral bands. The study investigates the impact of pansharpening on the spatial and spectral content of the data. It compares various image fusion techniques and their impact on land use classification results. The image fusion techniques investigated are Brovey Transform, High Pass Filtering, Principal Component Analysis, Wavelet Approach and Ehlers Fusion. The images are classified using a maximum likelihood classifier. The results show that the use of an appropriate image fusion technique with adequately tuned parameters can improve quality of the resulting thematic maps.
Remote sensing delivers multi-modal and -temporal data. Image fusion is a valuable tool to optimi... more Remote sensing delivers multi-modal and -temporal data. Image fusion is a valuable tool to optimize multisensor image exploitation. It has developed into a usable image processing technique to extract information of higher quality and reliability. Due to the availability of many different sensors and operational image fusion techniques researchers have conducted a vast amount of successful experiments. However, the definition of an appropriate workflow prior to processing the imagery requires knowledge in all related fields, i.e. remote sensing, image fusion and the desired image exploitation processing. From the results it is visible that the choice of the appropriate technique as well as the fine tuning of the individual parameters of this technique is crucial. There is still a lack of strategic guidelines due to its complexity and variability. This paper reports on the findings of an initiative to streamline data selection, application requirements and the choice of a suitable image fusion technique. All this forms the first step into the development a Fusion Approach Selection Tool (FAST). The project aims at collecting successful image fusion cases that are relevant to other users and other areas of interest. From there standards will be developed that apply to these cases that are valuable contributions to further applications and developments. The availability of these standards will help to further develop image fusion techniques, make best use of existing multimodal images and provide new insights on the processes of the Earth.
Remote sensing contributes valuable information to streamflow estimates. This paper discusses its... more Remote sensing contributes valuable information to streamflow estimates. This paper discusses its relevance to the digital earth concept. The authors categorize the role of remote sensing in streamflow modelling and estimation. This paper emphasizes the applications and challenges of satellite-based products in streamflow modelling. Importance and application of streamflow models is firstly described. Then, different classifications of models, modelling processes and several uncertainties sources that affect models prediction are explained. In addition, we explore the advantages of satellite precipitation estimates in modelling, uncertainties in remotely sensed data and some improvement techniques. The connection, relationship and contribution of remote sensing for streamflow modelling to digital earth principle are identified. Finally, we define and illustrate the future directions and necessary developments of streamflow measurement by remote sensing.
With Malaysia being the second largest palm oil producer in the world and the fact that palm oil ... more With Malaysia being the second largest palm oil producer in the world and the fact that palm oil ranks first in vegetable oil production on the world market the palm oil industry became an important factor in the country. Along with the expansion of palm oil across the nation causing deforestation of natural rain forest and conversion of peat land into plantation land there are several factors causing a tremendous increase in carbon dioxide (CO 2 ) emissions. Main causes of CO 2 emission apart from deforestation and peat-land conversion are the fires to create plantation land plus the fires burning waste products of the plantations itself. This paper describes a project that aims at the development of a remote sensing monitoring system to allow a continuous observation of oil palm plantation activities and expansion in order to be able to quantify CO 2 emissions. The research concentrates on developing a spaceborne synthetic aperture radar information extraction system for palm oil plantations in the Tropics. This will lead to objective figures that can be used internationally to create a policy implementation plan to sustainably reduce CO 2 emission in the future.
OPERATIONAL APPLICATIONS OF MULTISENSOR IMAGE FUSION
Space-based observation provides repeated, unrestricted access to every corner of the globe, in f... more Space-based observation provides repeated, unrestricted access to every corner of the globe, in full compliance with internatio nal law, and this capability may provide early warning of crises before action has to be taken to deal with them. Risks can be asse ssed before they turn into threats. The Western European Union Satellite Centre (WEUSC) operationally exploits imagery derived from
The high resolution remote sensing satellite Razaksat is a unique satellite system since it opera... more The high resolution remote sensing satellite Razaksat is a unique satellite system since it operates in a near-equatorial orbit with a low inclination angle of 9. In a first study scientists have found the images suitable for feature extraction in an urban context to update the road network at a scale of 1:25,000. In a preceding project for land cover mapping the research team used the five available bands of Razaksat imagery. This paper describes a continuation of the former study in which techniques are used to fuse the high resolution panchromatic band with the lower resolution multispectral bands. The study investigates the impact of pansharpening on the spatial and spectral content of the data. It compares various image fusion techniques and their impact on land use classification results. The image fusion techniques investigated are Brovey Transform, High Pass Filtering, Principal Component Analysis, Wavelet Approach and Ehlers Fusion. The images are classified using a maximum likelihood classifier. The results show that the use of an appropriate image fusion technique with adequately tuned parameters can improve quality of the resulting thematic maps.
The Western European Union Satellite Centre (WEUSC) operationally exploits multisensor data for s... more The Western European Union Satellite Centre (WEUSC) operationally exploits multisensor data for security oriented applications using data fusion techniques. Fused data can contribute to improved interpretation capabilities and more reliable results since data with different characteristics are combined. The input images vary in spectral and spatial resolution as well as in time and therefore give a more complete view of the objects observed. This paper outlines a research project initiated by WEUSC with the aim to demonstrate the benefit of data fusion using data from visible/infrared (VIR) and synthetic aperture RADAR (SAR) satellite sensors with regards to improved visual image interpretation. All three processing levels of data fusion are considered, i.e. pixel-based, feature-based and decision-based. Using advanced analytical or numerical data fusion techniques the data are processed for visual and semi-automatic interpretation to extract and analyse features of interest, in particular man-made objects, such as airfields, vehicles and infrastructure. After a short description of the WEUSC framework an introduction to the data fusion demonstrator (DFD) is given. The paper continues with a description of methodology, implementation, and first results obtained. It concludes with an evaluation of the experiences gained.
Image mapping using data from visible and infrared sensors has, as a major drawback, the frequent... more Image mapping using data from visible and infrared sensors has, as a major drawback, the frequent cloud cover experienced in many countries. This is one of the main reasons why topographic maps at 1:100,000 scale and larger are often outdated. The results of a study which investigated the possibilities of fusing up-to-date spaceborne microwave data with existing images from optical sensors for topographic map updating at a scale of 1:100, 000 are presented in this paper. A key issue researched was the influence of geometric distortions and corrections of remote sensing data on the results of pixel based digital image fusion. After having terrain-geocoded and radiometrically enhanced imagery from the Landsat, SPOT, ERS-1 and JERS-1 satellites, the data were fused applying a variety of colour transformation techniques as well as statistical or arithmetic methods. Initially, the image fusion was implemented using images covering a test site in the north of The Netherlands in order to calibrate specified combinations and techniques in a rather flat area. With the experience gained, the remote sensing data acquired over the research site were processed. The research test site is located in a typical Developing Country in the humid Tropics, on the mountainous south-west coast of Sumatra in Indonesia. The results of the various applied techniques and image combinations were evaluated with reference to their capability to overcome the cloud cover problem. New combinations of techniques and images were developed as result of an optimisation process. The research produced two prototypes of annotated 1:100,000 scale image maps containing fused, cloud-free optical/microwave imagery.
Image mapping using data from visible and infrared sensors has, as a major drawback, the frequent... more Image mapping using data from visible and infrared sensors has, as a major drawback, the frequent cloud cover experienced in many countries. This is one of the main reasons why topographic maps at 1:100,000 scale and larger are often outdated. The results of a study which investigated the possibilities of fusing up-to-date spaceborne microwave data with existing images from optical sensors for topographic map updating at a scale of 1:100, 000 are presented in this paper. A key issue researched was the influence of geometric distortions and corrections of remote sensing data on the results of pixel based digital image fusion. After having terrain-geocoded and radiometrically enhanced imagery from the Landsat, SPOT, ERS-1 and JERS-1 satellites, the data were fused applying a variety of colour transformation techniques as well as statistical or arithmetic methods. Initially, the image fusion was implemented using images covering a test site in the north of The Netherlands in order to calibrate specified combinations and techniques in a rather flat area. With the experience gained, the remote sensing data acquired over the research site were processed. The research test site is located in a typical Developing Country in the humid Tropics, on the mountainous south-west coast of Sumatra in Indonesia. The results of the various applied techniques and image combinations were evaluated with reference to their capability to overcome the cloud cover problem. New combinations of techniques and images were developed as result of an optimisation process. The research produced two prototypes of annotated 1:100,000 scale image maps containing fused, cloud-free optical/microwave imagery.
2014 IEEE Conference on Biomedical Engineering and Sciences (IECBES), 2014
Ahstract-In diagnosis, planning, intervention and monitoring of the potentially fatal Coronary Ar... more Ahstract-In diagnosis, planning, intervention and monitoring of the potentially fatal Coronary Artery Dis ease multimodal medical imaging plays an important role. Medical cardiac images of patients suffering from Athero sclerosis exhibit information on cardiovascular plaque that can cause a sudden death due to its vulnerability. The identification of vulnerable plaque is an important re search field and can be supported by the use of multimodal image fusion combining anatomical as well as functional information in one image medium. Image fusion has prov en to enhance critical components of the multimodal data sources that enable improved diagnostics and intervention. The advancement of image fusion techniques and an intel ligent selection of multimodal medical image combinations in the context of vulnerable plaque detection require an interdisciplinary approach. This paper reports on the first achievements of a collaborative research project involving clinicians and image processing engineers. During the first stage an interdisciplinary workflow was established. Criti cal research questions were identified. The second phase
The high resolution remote sensing satellite Razaksat is a unique satellite system since it opera... more The high resolution remote sensing satellite Razaksat is a unique satellite system since it operates in a near-equatorial orbit with a low inclination angle of 9. In a first study scientists have found the images suitable for feature extraction in an urban context to update the road network at a scale of 1:25,000. In a preceding project for land cover mapping the research team used the five available bands of Razaksat imagery. This paper describes a continuation of the former study in which techniques are used to fuse the high resolution panchromatic band with the lower resolution multispectral bands. The study investigates the impact of pansharpening on the spatial and spectral content of the data. It compares various image fusion techniques and their impact on land use classification results. The image fusion techniques investigated are Brovey Transform, High Pass Filtering, Principal Component Analysis, Wavelet Approach and Ehlers Fusion. The images are classified using a maximum likelihood classifier. The results show that the use of an appropriate image fusion technique with adequately tuned parameters can improve quality of the resulting thematic maps.
Remote sensing delivers multi-modal and -temporal data. Image fusion is a valuable tool to optimi... more Remote sensing delivers multi-modal and -temporal data. Image fusion is a valuable tool to optimize multisensor image exploitation. It has developed into a usable image processing technique to extract information of higher quality and reliability. Due to the availability of many different sensors and operational image fusion techniques researchers have conducted a vast amount of successful experiments. However, the definition of an appropriate workflow prior to processing the imagery requires knowledge in all related fields, i.e. remote sensing, image fusion and the desired image exploitation processing. From the results it is visible that the choice of the appropriate technique as well as the fine tuning of the individual parameters of this technique is crucial. There is still a lack of strategic guidelines due to its complexity and variability. This paper reports on the findings of an initiative to streamline data selection, application requirements and the choice of a suitable image fusion technique. All this forms the first step into the development a Fusion Approach Selection Tool (FAST). The project aims at collecting successful image fusion cases that are relevant to other users and other areas of interest. From there standards will be developed that apply to these cases that are valuable contributions to further applications and developments. The availability of these standards will help to further develop image fusion techniques, make best use of existing multimodal images and provide new insights on the processes of the Earth.
Remote sensing contributes valuable information to streamflow estimates. This paper discusses its... more Remote sensing contributes valuable information to streamflow estimates. This paper discusses its relevance to the digital earth concept. The authors categorize the role of remote sensing in streamflow modelling and estimation. This paper emphasizes the applications and challenges of satellite-based products in streamflow modelling. Importance and application of streamflow models is firstly described. Then, different classifications of models, modelling processes and several uncertainties sources that affect models prediction are explained. In addition, we explore the advantages of satellite precipitation estimates in modelling, uncertainties in remotely sensed data and some improvement techniques. The connection, relationship and contribution of remote sensing for streamflow modelling to digital earth principle are identified. Finally, we define and illustrate the future directions and necessary developments of streamflow measurement by remote sensing.
With Malaysia being the second largest palm oil producer in the world and the fact that palm oil ... more With Malaysia being the second largest palm oil producer in the world and the fact that palm oil ranks first in vegetable oil production on the world market the palm oil industry became an important factor in the country. Along with the expansion of palm oil across the nation causing deforestation of natural rain forest and conversion of peat land into plantation land there are several factors causing a tremendous increase in carbon dioxide (CO 2 ) emissions. Main causes of CO 2 emission apart from deforestation and peat-land conversion are the fires to create plantation land plus the fires burning waste products of the plantations itself. This paper describes a project that aims at the development of a remote sensing monitoring system to allow a continuous observation of oil palm plantation activities and expansion in order to be able to quantify CO 2 emissions. The research concentrates on developing a spaceborne synthetic aperture radar information extraction system for palm oil plantations in the Tropics. This will lead to objective figures that can be used internationally to create a policy implementation plan to sustainably reduce CO 2 emission in the future.
OPERATIONAL APPLICATIONS OF MULTISENSOR IMAGE FUSION
Space-based observation provides repeated, unrestricted access to every corner of the globe, in f... more Space-based observation provides repeated, unrestricted access to every corner of the globe, in full compliance with internatio nal law, and this capability may provide early warning of crises before action has to be taken to deal with them. Risks can be asse ssed before they turn into threats. The Western European Union Satellite Centre (WEUSC) operationally exploits imagery derived from
The high resolution remote sensing satellite Razaksat is a unique satellite system since it opera... more The high resolution remote sensing satellite Razaksat is a unique satellite system since it operates in a near-equatorial orbit with a low inclination angle of 9. In a first study scientists have found the images suitable for feature extraction in an urban context to update the road network at a scale of 1:25,000. In a preceding project for land cover mapping the research team used the five available bands of Razaksat imagery. This paper describes a continuation of the former study in which techniques are used to fuse the high resolution panchromatic band with the lower resolution multispectral bands. The study investigates the impact of pansharpening on the spatial and spectral content of the data. It compares various image fusion techniques and their impact on land use classification results. The image fusion techniques investigated are Brovey Transform, High Pass Filtering, Principal Component Analysis, Wavelet Approach and Ehlers Fusion. The images are classified using a maximum likelihood classifier. The results show that the use of an appropriate image fusion technique with adequately tuned parameters can improve quality of the resulting thematic maps.
The Western European Union Satellite Centre (WEUSC) operationally exploits multisensor data for s... more The Western European Union Satellite Centre (WEUSC) operationally exploits multisensor data for security oriented applications using data fusion techniques. Fused data can contribute to improved interpretation capabilities and more reliable results since data with different characteristics are combined. The input images vary in spectral and spatial resolution as well as in time and therefore give a more complete view of the objects observed. This paper outlines a research project initiated by WEUSC with the aim to demonstrate the benefit of data fusion using data from visible/infrared (VIR) and synthetic aperture RADAR (SAR) satellite sensors with regards to improved visual image interpretation. All three processing levels of data fusion are considered, i.e. pixel-based, feature-based and decision-based. Using advanced analytical or numerical data fusion techniques the data are processed for visual and semi-automatic interpretation to extract and analyse features of interest, in particular man-made objects, such as airfields, vehicles and infrastructure. After a short description of the WEUSC framework an introduction to the data fusion demonstrator (DFD) is given. The paper continues with a description of methodology, implementation, and first results obtained. It concludes with an evaluation of the experiences gained.
Image mapping using data from visible and infrared sensors has, as a major drawback, the frequent... more Image mapping using data from visible and infrared sensors has, as a major drawback, the frequent cloud cover experienced in many countries. This is one of the main reasons why topographic maps at 1:100,000 scale and larger are often outdated. The results of a study which investigated the possibilities of fusing up-to-date spaceborne microwave data with existing images from optical sensors for topographic map updating at a scale of 1:100, 000 are presented in this paper. A key issue researched was the influence of geometric distortions and corrections of remote sensing data on the results of pixel based digital image fusion. After having terrain-geocoded and radiometrically enhanced imagery from the Landsat, SPOT, ERS-1 and JERS-1 satellites, the data were fused applying a variety of colour transformation techniques as well as statistical or arithmetic methods. Initially, the image fusion was implemented using images covering a test site in the north of The Netherlands in order to calibrate specified combinations and techniques in a rather flat area. With the experience gained, the remote sensing data acquired over the research site were processed. The research test site is located in a typical Developing Country in the humid Tropics, on the mountainous south-west coast of Sumatra in Indonesia. The results of the various applied techniques and image combinations were evaluated with reference to their capability to overcome the cloud cover problem. New combinations of techniques and images were developed as result of an optimisation process. The research produced two prototypes of annotated 1:100,000 scale image maps containing fused, cloud-free optical/microwave imagery.
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Papers by Christine Pohl