Panos Liatsis | City, University of London (original) (raw)
Papers by Panos Liatsis
This paper forms part of an ongoing research to derive a Generalised Forward Formulation (GFF) fo... more This paper forms part of an ongoing research to derive a Generalised Forward Formulation (GFF) for the forward problem in EIT capable of accommodating irregular and moving boundary surfaces. In this work, we introduce a promising conceptual and numerical blend for the EIT problem namely the use of wavelets in Domain Embedding methods. In principle, the original domain is registered
This paper forms part of an ongoing research to derive a generalised formulation for the forward ... more This paper forms part of an ongoing research to derive a generalised formulation for the forward problem in EIT capable of accommodating irregular and moving boundary surfaces, ideally, under a exible and scalable conguration. Wavelets, as basis functions, seem to be the best candidate in supporting such a framework and here are investigated as an alternative to the standard, tailored
Lecture Notes in Computer Science, 2006
This work concerns the design and development of a driving simulation system, which exhibits inte... more This work concerns the design and development of a driving simulation system, which exhibits intelligent driving behaviour at the tactical level, as part of a traffic simulation environment. Our tactical driving system using genetic algorithms, named GA-INTACT, accounts for the subject vehicle and other vehicles positions and speed parameters in the surrounding traffic condition, and selects favourable speed change and lane transition actions for the ‘subject’ vehicle, according to safety, speed and driving behaviour criteria. Simulation results demonstrated that the adoption of the Genetic Algorithms approach for obtaining near-optimum driving solutions eliminates the need for learning driving patterns, and allows the efficient handling of the complex nature of tactical driving modelling problem. The role of the driving behaviour in influencing the outcome of the driver’s decision is emphasised, an aspect that was not treated sufficiently in previous tactical driving simulation approaches.
2009 Second International Conference on Developments in eSystems Engineering, 2009
In this paper, we present a novel framework to segment and quantify stenosed coronary arteries in... more In this paper, we present a novel framework to segment and quantify stenosed coronary arteries in 3D contrast enhanced computed tomography angiography (CTA). According to our knowledge, no commercially available software package permits fully automated detection and assessment of atherosclerotic stenosis. Therefore, in clinical practice, the radiologist has to make a detailed evaluation, segment by segment, which is obviously a
In patient-specific coronary blood flow modelling, the computational domain is defined as a 3D me... more In patient-specific coronary blood flow modelling, the computational domain is defined as a 3D mesh of the major coronary arteries reconstructed from medical images. Blood flow itself is described through the flow equations that are defined over this computational domain and further solved by methods of computational fluid dynamics (CFD) in terms of pressure and velocity fields. One of the major factors determining the accuracy of the computed flow fields is the appropriate specification of flow conditions on the boundaries of the domain that represent the impact of the remaining (undefined) parts of the cardiovascular system (CVS). Boundary conditions (BC) can be assigned either explicitly or implicitly; the difference being in the presence, or not of interaction between the domain (3D arteries) and the upstream/downstream vasculature. Application of more advanced implicit BC provides the means to model the adjustment of blood flow, depending on the downstream impedance and intramyocardial pressure, which results in "more realistic" computed blood fields. However, this also introduces a level of uncertainty, as blood flow in the required zones of CVS is unknown a priori and is generally difficult to measure in clinical practice, due to the highly invasive nature of the procedure. This work presents an analysis of the requirements for boundary conditions in the context of physiologically realistic simulations of coronary blood flow. This is elucidated through the analysis of 3D blood flow in patient-specific left coronary artery (LCA) cases. Moreover, a comparison between implicit and explicit BC and the methods of modelling patient-specific flow within the rest of CVS is provided.
Gradient operators are used in image processing and computer vision to detect edges and estimate ... more Gradient operators are used in image processing and computer vision to detect edges and estimate their local orientation. Most operators have to process the entire image. In this paper, an edge contour extraction technique is presented. The proposed technique is based on the gradient magnitude and a quantisation of gradient directions. Its distinctive aspect consists in that the technique does not process the entire image to extract edge contours. It detects an edge region and locates an edge. The pixel coordinates where the edge is located are used as an anchor for tracking an edge contour. Edges in a contour have a common quantised gradient direction. Experimental validation using ground-truth edge images is presented. The proposed technique is compared to the Sobel and the Canny operators. It produces results similar to the Canny edge detector, in terms of true positive rate, false positive rate and false positive edge probability.
Proceedings of IEEE International Conference on Control and Applications CCA-94, 1994
The dynamically changing nature and the complex behaviour of processes in manufacturing cells dic... more The dynamically changing nature and the complex behaviour of processes in manufacturing cells dictate the need for lean, agile and flexible manufacturing systems. This research describes a versatile, intelligent vision system capable of performing a variety of tasks for the manufacturing process. The key features of the system are reconfigurability, adaptation, and real-time performance. It is based on higher-order neural
Journal of Microcomputer Applications, 1993
7th Mediterranean Conference and Exhibition on Power Generation, Transmission, Distribution and Energy Conversion (MedPower 2010), 2010
Cooperation project that addresses the needs of South-East European Transmission Systems Operator... more Cooperation project that addresses the needs of South-East European Transmission Systems Operators (TSOs) in their effort towards harmonization and integration of the region with the rest of the European power network. Project objectives are the creation of a monitoring and simulation toolbox that can be deployed and tested rapidly and cost-effectively, to assist in harmonizing regulatory and commercial frameworks in South East Europe, the development of systems and tools that will enable all players in the energy field to utilize innovative service arrangements to improve their efficiency and enhance their services to customers, to develop and implement methods and techniques for capacity calculation and allocation, to establish corrective procedures to ensure security of power transmission and grid connections, to ensure successful interfacing between new and old representation and modeling methods of power networks and the development of traditional and modern techniques to serve for experimentation and decision making.
2004 IEEE Symposium on Virtual Environments, Human-Computer Interfaces and Measurement Systems, 2004. (VCIMS)., 2004
a computer in real rime. Ir uses a posirion ohsener fo record the mirror posirion and with a feed... more a computer in real rime. Ir uses a posirion ohsener fo record the mirror posirion and with a feedback loop correcrs rhe tilt ofrhe moving mirmr in rhe inrerfemmerer This relarively simple sysrem is v e q effective and can be applied ro other scanning oprical inrerfemmerers. Keywords -Alignmenr, Michelson inrerfemmerer: arrive conrml, phase derecrion, near infrared.
Conference proceedings : ... Annual International Conference of the IEEE Engineering in Medicine and Biology Society. IEEE Engineering in Medicine and Biology Society. Annual Conference, 2011
In the forward EIT-problem numerical solutions of an elliptic partial differential equation are r... more In the forward EIT-problem numerical solutions of an elliptic partial differential equation are required. Given the arbitrary geometries encountered, the Finite Element Method (FEM) is, naturally, the method of choice. Nowadays, in EIT applications, there is an increasing demand for finer Finite Element mesh models. This in turn results to a soaring number of degrees of freedom and an excessive number of unknowns. As such, only piece-wise linear basis functions can practically be employed to maintain inexpensive computations. In addition, domain reduction and/or compression schemes are often sought to further counteract for the growing number of unknowns. In this paper, we replace the piece-wise linear with wavelet basis functions (coupled with the domain embedding method) to enable sparse approximations of the forward computations. Given that the forward solutions are repeatedly, if not extensively, utilised during the image reconstruction process, considerable computational saving...
ABSTRACT Imposing prior information is a typical strategy in inverse problems in return for a sta... more ABSTRACT Imposing prior information is a typical strategy in inverse problems in return for a stable numerical algorithm. For a given imaging system configuration, Picard's stability condition could be deployed as a practical measure of the performance of the system against various priors and noise contaminated measurements. Herein, we make extensive use of this measure to quantify the performance of impedance imaging systems for various injection patterns. In effect, we numerically demonstrate that by varying electrode distributions and numbers, little improvement, if any, in the performance of the impedance imaging system is recorded. In contrast, by using groups of electrodes in the 3D current injection process, a step increase in performance is obtained. Numerical results on a female breast phantom reveal that the performance measure of the imaging system is 15% for a conventional combination of stimulation and prior information, 61% for groups of electrodes and the same prior and 97% for groups of electrodes and a more accurate prior. Finally, since a smaller number of electrodes is involved in the measurement process, a smaller number of measurements is acquired. However, no compromise in the quality of the reconstructed images is observed.
2009 Second International Conference on Developments in eSystems Engineering, 2009
In the past years, much research has been done about ocular hemodynamics using fluorescein angiog... more In the past years, much research has been done about ocular hemodynamics using fluorescein angiography. One of the most promising parameters is the transit time of retinal blood flow, which tries to determining how long a dye takes in reach, fills out and leaves the human retina. To achieve this, both individual angiograms and sets of them have to be
The current demand for versatile medical diagnostics has created a significant increase in the de... more The current demand for versatile medical diagnostics has created a significant increase in the development of NIR spectroscopic techniques due to the relative transparency of body fluids and soft tissue in this spectral region. Specifically the non-invasive determination of blood substrates is a desirable measurement as a guide to the pathological condition of the patient, since blood forms the primary
Optic disc detection is an important task in retinal imaging due to its significance in both clin... more Optic disc detection is an important task in retinal imaging due to its significance in both clinical and image understanding aspects. In the clinical setting, the optic disc represents the entrance and exit sites of vascular and nervous structures, and its size and shape could be used in diagnostics and treatment of diseases, such as glaucoma. In terms of automated retinal analysis systems, it is used as a landmark point in retinal image registration, the starting point for vessel tracking, and in determining the geometry of the retina. Several approaches have been proposed, the majority of which use intensity - or shape-based techniques. Recently, approaches that combine intensity, shape and information regarding vascular structures have been used with good results. In this paper, a method that combines information from the major blood vessels is investigated and compared with intensity - and shape-based techniques, when used on their own. The image set employed to evaluate the pr...
ARCHIVE Proceedings of the Institution of Mechanical Engineers Part C Journal of Mechanical Engineering Science 1989-1996 (vols 203-210)
It is well-known that age-related macular degeneration is the main cause of visual impairment in ... more It is well-known that age-related macular degeneration is the main cause of visual impairment in industrialised countries affecting around 239,000 people in UK while demonstrating an increasing trend. Fluorescein angiography is the most widely used technique in the diagnosis, prognosis and in following up the development of the disease. The interpretation of fluorescein angiograms depends upon the detection of abnormal fluorescence and clinical assessment of the functional integrity of retinal circulation, which is primarily based on subjective evaluation of the dye transit-time. This study presents a prototype system for quantitative analysis of the retinal haemodynamics. It analyses retinal blood flow based on the estimation of parameters such as mean transit-time, arteriovenous passage time and mean dye velocity. These parameters are estimated using densitometry and analysis of the vascular response. The prototype system consists of three main stages: vessel segmentation, image r...
Iet Science Measurement & Technology, 2007
Artificial neural networks (ANNs) are addressed in order to assess the electric and magnetic fiel... more Artificial neural networks (ANNs) are addressed in order to assess the electric and magnetic field radiating by electrostatic discharges (ESDs). Actual input and output data collected from hundreds of measurements carried out in the High Voltage Laboratory of the National Technical University of Athens are used in the training, validation and testing process. The developed ANN method is coded in a comprehensive software tool to be used by laboratories involved in ESD tests, which either face a lack of suitable measuring equipment or want to compare their own measurements. The electromagnetic field produced by radiating ESDs, can be assessed very easily and accurately by simply measuring and providing to the tool the discharge current. The authors strongly believe that the proposed ANN software tool can be extremely useful for laboratories involved in ESD tests according to the current IEC Standard, as the forthcoming revised version of this standard will almost certainly include measurements of the radiating electromagnetic field during the verification of ESD generators.
2010 Annual International Conference of the IEEE Engineering in Medicine and Biology, 2010
In this paper, we employ the concept of the Fisher information matrix (FIM) to reformulate and im... more In this paper, we employ the concept of the Fisher information matrix (FIM) to reformulate and improve on the "Newton's One-Step Error Reconstructor" (NOSER) algorithm. FIM is a systematic approach for incorporating statistical properties of noise, modeling errors and multi-frequency data. The method is discussed in a maximum likelihood estimator (MLE) setting. The ill-posedness of the inverse problem is mitigated by means of a nonlinear regularization strategy. It is shown that the overall approach reduces to the maximum a posteriori estimator (MAP) with the prior (conductivity vector) described by a multivariate normal distribution. The covariance matrix of the prior is a diagonal matrix and is computed directly from the Fisher information matrix. An eigenvalue analysis is presented, revealing the advantages of using this prior to a Gaussian smoothness prior (Laplace). Reconstructions are shown using measured data obtained from a shallow breathing of an adult human subject. The reconstructions show that the FIM approach clearly improves on the original NOSER algorithm.
This paper forms part of an ongoing research to derive a Generalised Forward Formulation (GFF) fo... more This paper forms part of an ongoing research to derive a Generalised Forward Formulation (GFF) for the forward problem in EIT capable of accommodating irregular and moving boundary surfaces. In this work, we introduce a promising conceptual and numerical blend for the EIT problem namely the use of wavelets in Domain Embedding methods. In principle, the original domain is registered
This paper forms part of an ongoing research to derive a generalised formulation for the forward ... more This paper forms part of an ongoing research to derive a generalised formulation for the forward problem in EIT capable of accommodating irregular and moving boundary surfaces, ideally, under a exible and scalable conguration. Wavelets, as basis functions, seem to be the best candidate in supporting such a framework and here are investigated as an alternative to the standard, tailored
Lecture Notes in Computer Science, 2006
This work concerns the design and development of a driving simulation system, which exhibits inte... more This work concerns the design and development of a driving simulation system, which exhibits intelligent driving behaviour at the tactical level, as part of a traffic simulation environment. Our tactical driving system using genetic algorithms, named GA-INTACT, accounts for the subject vehicle and other vehicles positions and speed parameters in the surrounding traffic condition, and selects favourable speed change and lane transition actions for the ‘subject’ vehicle, according to safety, speed and driving behaviour criteria. Simulation results demonstrated that the adoption of the Genetic Algorithms approach for obtaining near-optimum driving solutions eliminates the need for learning driving patterns, and allows the efficient handling of the complex nature of tactical driving modelling problem. The role of the driving behaviour in influencing the outcome of the driver’s decision is emphasised, an aspect that was not treated sufficiently in previous tactical driving simulation approaches.
2009 Second International Conference on Developments in eSystems Engineering, 2009
In this paper, we present a novel framework to segment and quantify stenosed coronary arteries in... more In this paper, we present a novel framework to segment and quantify stenosed coronary arteries in 3D contrast enhanced computed tomography angiography (CTA). According to our knowledge, no commercially available software package permits fully automated detection and assessment of atherosclerotic stenosis. Therefore, in clinical practice, the radiologist has to make a detailed evaluation, segment by segment, which is obviously a
In patient-specific coronary blood flow modelling, the computational domain is defined as a 3D me... more In patient-specific coronary blood flow modelling, the computational domain is defined as a 3D mesh of the major coronary arteries reconstructed from medical images. Blood flow itself is described through the flow equations that are defined over this computational domain and further solved by methods of computational fluid dynamics (CFD) in terms of pressure and velocity fields. One of the major factors determining the accuracy of the computed flow fields is the appropriate specification of flow conditions on the boundaries of the domain that represent the impact of the remaining (undefined) parts of the cardiovascular system (CVS). Boundary conditions (BC) can be assigned either explicitly or implicitly; the difference being in the presence, or not of interaction between the domain (3D arteries) and the upstream/downstream vasculature. Application of more advanced implicit BC provides the means to model the adjustment of blood flow, depending on the downstream impedance and intramyocardial pressure, which results in "more realistic" computed blood fields. However, this also introduces a level of uncertainty, as blood flow in the required zones of CVS is unknown a priori and is generally difficult to measure in clinical practice, due to the highly invasive nature of the procedure. This work presents an analysis of the requirements for boundary conditions in the context of physiologically realistic simulations of coronary blood flow. This is elucidated through the analysis of 3D blood flow in patient-specific left coronary artery (LCA) cases. Moreover, a comparison between implicit and explicit BC and the methods of modelling patient-specific flow within the rest of CVS is provided.
Gradient operators are used in image processing and computer vision to detect edges and estimate ... more Gradient operators are used in image processing and computer vision to detect edges and estimate their local orientation. Most operators have to process the entire image. In this paper, an edge contour extraction technique is presented. The proposed technique is based on the gradient magnitude and a quantisation of gradient directions. Its distinctive aspect consists in that the technique does not process the entire image to extract edge contours. It detects an edge region and locates an edge. The pixel coordinates where the edge is located are used as an anchor for tracking an edge contour. Edges in a contour have a common quantised gradient direction. Experimental validation using ground-truth edge images is presented. The proposed technique is compared to the Sobel and the Canny operators. It produces results similar to the Canny edge detector, in terms of true positive rate, false positive rate and false positive edge probability.
Proceedings of IEEE International Conference on Control and Applications CCA-94, 1994
The dynamically changing nature and the complex behaviour of processes in manufacturing cells dic... more The dynamically changing nature and the complex behaviour of processes in manufacturing cells dictate the need for lean, agile and flexible manufacturing systems. This research describes a versatile, intelligent vision system capable of performing a variety of tasks for the manufacturing process. The key features of the system are reconfigurability, adaptation, and real-time performance. It is based on higher-order neural
Journal of Microcomputer Applications, 1993
7th Mediterranean Conference and Exhibition on Power Generation, Transmission, Distribution and Energy Conversion (MedPower 2010), 2010
Cooperation project that addresses the needs of South-East European Transmission Systems Operator... more Cooperation project that addresses the needs of South-East European Transmission Systems Operators (TSOs) in their effort towards harmonization and integration of the region with the rest of the European power network. Project objectives are the creation of a monitoring and simulation toolbox that can be deployed and tested rapidly and cost-effectively, to assist in harmonizing regulatory and commercial frameworks in South East Europe, the development of systems and tools that will enable all players in the energy field to utilize innovative service arrangements to improve their efficiency and enhance their services to customers, to develop and implement methods and techniques for capacity calculation and allocation, to establish corrective procedures to ensure security of power transmission and grid connections, to ensure successful interfacing between new and old representation and modeling methods of power networks and the development of traditional and modern techniques to serve for experimentation and decision making.
2004 IEEE Symposium on Virtual Environments, Human-Computer Interfaces and Measurement Systems, 2004. (VCIMS)., 2004
a computer in real rime. Ir uses a posirion ohsener fo record the mirror posirion and with a feed... more a computer in real rime. Ir uses a posirion ohsener fo record the mirror posirion and with a feedback loop correcrs rhe tilt ofrhe moving mirmr in rhe inrerfemmerer This relarively simple sysrem is v e q effective and can be applied ro other scanning oprical inrerfemmerers. Keywords -Alignmenr, Michelson inrerfemmerer: arrive conrml, phase derecrion, near infrared.
Conference proceedings : ... Annual International Conference of the IEEE Engineering in Medicine and Biology Society. IEEE Engineering in Medicine and Biology Society. Annual Conference, 2011
In the forward EIT-problem numerical solutions of an elliptic partial differential equation are r... more In the forward EIT-problem numerical solutions of an elliptic partial differential equation are required. Given the arbitrary geometries encountered, the Finite Element Method (FEM) is, naturally, the method of choice. Nowadays, in EIT applications, there is an increasing demand for finer Finite Element mesh models. This in turn results to a soaring number of degrees of freedom and an excessive number of unknowns. As such, only piece-wise linear basis functions can practically be employed to maintain inexpensive computations. In addition, domain reduction and/or compression schemes are often sought to further counteract for the growing number of unknowns. In this paper, we replace the piece-wise linear with wavelet basis functions (coupled with the domain embedding method) to enable sparse approximations of the forward computations. Given that the forward solutions are repeatedly, if not extensively, utilised during the image reconstruction process, considerable computational saving...
ABSTRACT Imposing prior information is a typical strategy in inverse problems in return for a sta... more ABSTRACT Imposing prior information is a typical strategy in inverse problems in return for a stable numerical algorithm. For a given imaging system configuration, Picard's stability condition could be deployed as a practical measure of the performance of the system against various priors and noise contaminated measurements. Herein, we make extensive use of this measure to quantify the performance of impedance imaging systems for various injection patterns. In effect, we numerically demonstrate that by varying electrode distributions and numbers, little improvement, if any, in the performance of the impedance imaging system is recorded. In contrast, by using groups of electrodes in the 3D current injection process, a step increase in performance is obtained. Numerical results on a female breast phantom reveal that the performance measure of the imaging system is 15% for a conventional combination of stimulation and prior information, 61% for groups of electrodes and the same prior and 97% for groups of electrodes and a more accurate prior. Finally, since a smaller number of electrodes is involved in the measurement process, a smaller number of measurements is acquired. However, no compromise in the quality of the reconstructed images is observed.
2009 Second International Conference on Developments in eSystems Engineering, 2009
In the past years, much research has been done about ocular hemodynamics using fluorescein angiog... more In the past years, much research has been done about ocular hemodynamics using fluorescein angiography. One of the most promising parameters is the transit time of retinal blood flow, which tries to determining how long a dye takes in reach, fills out and leaves the human retina. To achieve this, both individual angiograms and sets of them have to be
The current demand for versatile medical diagnostics has created a significant increase in the de... more The current demand for versatile medical diagnostics has created a significant increase in the development of NIR spectroscopic techniques due to the relative transparency of body fluids and soft tissue in this spectral region. Specifically the non-invasive determination of blood substrates is a desirable measurement as a guide to the pathological condition of the patient, since blood forms the primary
Optic disc detection is an important task in retinal imaging due to its significance in both clin... more Optic disc detection is an important task in retinal imaging due to its significance in both clinical and image understanding aspects. In the clinical setting, the optic disc represents the entrance and exit sites of vascular and nervous structures, and its size and shape could be used in diagnostics and treatment of diseases, such as glaucoma. In terms of automated retinal analysis systems, it is used as a landmark point in retinal image registration, the starting point for vessel tracking, and in determining the geometry of the retina. Several approaches have been proposed, the majority of which use intensity - or shape-based techniques. Recently, approaches that combine intensity, shape and information regarding vascular structures have been used with good results. In this paper, a method that combines information from the major blood vessels is investigated and compared with intensity - and shape-based techniques, when used on their own. The image set employed to evaluate the pr...
ARCHIVE Proceedings of the Institution of Mechanical Engineers Part C Journal of Mechanical Engineering Science 1989-1996 (vols 203-210)
It is well-known that age-related macular degeneration is the main cause of visual impairment in ... more It is well-known that age-related macular degeneration is the main cause of visual impairment in industrialised countries affecting around 239,000 people in UK while demonstrating an increasing trend. Fluorescein angiography is the most widely used technique in the diagnosis, prognosis and in following up the development of the disease. The interpretation of fluorescein angiograms depends upon the detection of abnormal fluorescence and clinical assessment of the functional integrity of retinal circulation, which is primarily based on subjective evaluation of the dye transit-time. This study presents a prototype system for quantitative analysis of the retinal haemodynamics. It analyses retinal blood flow based on the estimation of parameters such as mean transit-time, arteriovenous passage time and mean dye velocity. These parameters are estimated using densitometry and analysis of the vascular response. The prototype system consists of three main stages: vessel segmentation, image r...
Iet Science Measurement & Technology, 2007
Artificial neural networks (ANNs) are addressed in order to assess the electric and magnetic fiel... more Artificial neural networks (ANNs) are addressed in order to assess the electric and magnetic field radiating by electrostatic discharges (ESDs). Actual input and output data collected from hundreds of measurements carried out in the High Voltage Laboratory of the National Technical University of Athens are used in the training, validation and testing process. The developed ANN method is coded in a comprehensive software tool to be used by laboratories involved in ESD tests, which either face a lack of suitable measuring equipment or want to compare their own measurements. The electromagnetic field produced by radiating ESDs, can be assessed very easily and accurately by simply measuring and providing to the tool the discharge current. The authors strongly believe that the proposed ANN software tool can be extremely useful for laboratories involved in ESD tests according to the current IEC Standard, as the forthcoming revised version of this standard will almost certainly include measurements of the radiating electromagnetic field during the verification of ESD generators.
2010 Annual International Conference of the IEEE Engineering in Medicine and Biology, 2010
In this paper, we employ the concept of the Fisher information matrix (FIM) to reformulate and im... more In this paper, we employ the concept of the Fisher information matrix (FIM) to reformulate and improve on the "Newton's One-Step Error Reconstructor" (NOSER) algorithm. FIM is a systematic approach for incorporating statistical properties of noise, modeling errors and multi-frequency data. The method is discussed in a maximum likelihood estimator (MLE) setting. The ill-posedness of the inverse problem is mitigated by means of a nonlinear regularization strategy. It is shown that the overall approach reduces to the maximum a posteriori estimator (MAP) with the prior (conductivity vector) described by a multivariate normal distribution. The covariance matrix of the prior is a diagonal matrix and is computed directly from the Fisher information matrix. An eigenvalue analysis is presented, revealing the advantages of using this prior to a Gaussian smoothness prior (Laplace). Reconstructions are shown using measured data obtained from a shallow breathing of an adult human subject. The reconstructions show that the FIM approach clearly improves on the original NOSER algorithm.