@article {garbe2003c,
	title = {Estimation of complex motion from thermographic image sequences},
	journal = {SPIE Proc.},
	volume = {5073},
	year = {2003},
	pages = {303--317},
	abstract = {In this contribution a novel technique for computing complexmotion involving heat transport processes will be presented. Theproposed technique is a local gradient based approach, combiningtransport models with motion analysis. It allows for thesimultaneous estimation of both motion and parameter of anunderlying transport model. Since the analysis is based on thermalimage sequences, estimates are computed to a high temporal andspatial resolution, limited only by the resolution and frame rateof the employed IR camera. This novel technique was utilized onexchange processes at the atmosphere/ocean boundary, wheresignificant parameters of heat transfer could be measured and atransport model verified. Using the presented algorithms, surfaceflows as well as convergences and divergences on air-waterinterfaces can be measured accurately. Apart from applications inoceanography and botany, relevant benefits of the proposedtechnique to NDT will be presented. It is possible to compensatefor motion to reach accuracies much better than 1/10th of a pixel.Through the direct estimation of locally resolved diffusivities inmaterials, insights can be gained about defects present. Byestimating not only isotropic diffusion but also the whole matrixof anisotropic diffusion, the technique is highly relevant tomeasurements of composite materials.},
	doi = {10.1117/12.501121},
	author = {Christoph S. Garbe and Hagen Spies and Bernd J{\"a}hne}
}
@article {garbe2003b,
	title = {Estimation of surface flow and net heat flux from infrared image sequences},
	journal = {Journal of Mathematical Imaging and Vision},
	volume = {19},
	number = {3},
	year = {2003},
	pages = {159--174},
	abstract = {The study of dynamical processes at the sea surface interface using infrared image sequence analysis has gained tremendous popularity in recent years. Heat is transferred by similar transport mechanisms as gases relevant to global climatic changes. These similarities lead to the use of infrared cameras to remotely visualize and quantitatively estimate parameters of the underlying processes. Relevant parameters that provide important evidence about the models of air-sea gas transfer are the temperature difference across the thermal sub layer, the probability density function of surface renewal and the flow field at the surface. Being a driving force in air sea interactions, it is of equal importance to measure heat fluxes. In this paper we will present algorithms to measure the above parameters of air-sea gas transfer during night-time and show how to combine physical modeling and quantitative digital image processing algorithms to identify transport models. The image processing routines rely on an extension of optical flow computations to incorporate brightness changes in a total least squares (TLS) framework. Statistical methods are employed to support a model of gas transfer and estimate its parameters. Measurements in a laboratory environment were conducted and results verified with ground truth data gained from traditional measurement techniques.},
	doi = {10.1023/A:1026233919766},
	author = {Christoph S. Garbe and Hagen Spies and Bernd J{\"a}hne}
}
@incollection {spies2002f,
	title = {3D-Blattbewegung und Wachstum},
	year = {2002},
	pages = {267--270},
	publisher = {Wichmann},
	url = {http://d-nb.info/96618503X},
	author = {Hagen Spies and Bernd J{\"a}hne},
	editor = {Thomas Luhmann}
}
@incollection {klar2002,
	title = {3D-Str{\"o}mungsmessung in Kiesporen},
	year = {2002},
	pages = {247--250},
	publisher = {Wichmann},
	url = {http://d-nb.info/96618503X},
	author = {Michael Klar and P. Stybalkowski and Hagen Spies and Bernd J{\"a}hne},
	editor = {Thomas Luhmann}
}
@conference {spies2002b,
	title = {Dense parameter fields from total least squares},
	booktitle = {Proceedings of the 24th DAGM Symposium on Pattern Recognition},
	volume = {LNCS 2449},
	year = {2002},
	pages = {379--386},
	publisher = {Springer},
	organization = {Springer},
	abstract = {A method for the interpolation of parameter fields estimated by total least squares is presented. This is applied to the study of dynamic processes where the motion and further values such as divergence or brightness changes are parameterised in a partial differential equation. For the regularisation we introduce a constraint that restricts the solution only in the subspace determined by the total least squares procedure. The performance is illustrated on both synthetic and real test data.},
	doi = {10.1007/3-540-45783-6_46},
	author = {Hagen Spies and Christoph S. Garbe},
	editor = {Luc Van Gool}
}
@conference {spies2002e,
	title = {Estimating expansion rates from range data sequences},
	booktitle = {15th International Conference on Vision Interface},
	year = {2002},
	pages = {339 - 346},
	author = {Hagen Spies and John L. Barron}
}
@conference {spies2002,
	title = {Evaluating the range flow motion constraint.},
	booktitle = {ICPR},
	year = {2002},
	pages = {517--},
	author = {Hagen Spies and John L. Barron}
}
@conference {spies2002a,
	title = {Local models for dynamic processes in image sequences},
	booktitle = {Dynamic Perception},
	year = {2002},
	pages = {59--64},
	publisher = {Aka GmbH},
	organization = {Aka GmbH},
	author = {Hagen Spies and Tobias Dierig and Christoph S. Garbe and W{\"u}rtz, R. P.},
	editor = {Lappe, M.}
}
@conference {klar2002a,
	title = {A miniaturized 3-D particle-tracking velocimetry system to measure the pore flow within a gravel layer},
	booktitle = {Proc. 11th Int. Symp. Applications of Laser Techniques to Fluid Mechanics},
	year = {2002},
	pages = {2.3},
	url = {http://in3.dem.ist.utl.pt/lxlaser2002/papers.asp},
	author = {Michael Klar and P. Stybalkowski and Hagen Spies and Bernd J{\"a}hne}
}
@conference {garbe2002e,
	title = {Mixed OLS-TLS for the estimation of dynamic processes with a linear source term},
	booktitle = {Proceedings of the 24th DAGM Symposium on Pattern Recognition},
	volume = {2449},
	year = {2002},
	pages = {463--471},
	publisher = {Springer-Verlag},
	organization = {Springer-Verlag},
	abstract = {We present a novel technique to eliminate strong biases in parameter estimation were part of the data matrix is not corrupted by errors. Problems of this type occur in the simultaneous estimation of optical flow and the parameter of linear brightness change as well as in range flow estimation. For attaining highly accurate optical flow estimations under real world situations as required by a number of scientific applications, the standard brightness change constraint equation is violated. Very often the brightness change has to be modelled by a linear source term. In this problem as well as in range flow estimation, part of the data term consists of an exactly known constant. Total least squares (TLS) assumes the error in the data terms to be identically distributed, thus leading to strong biases in the equations at hand. The approach presented in this paper is based on a mixture of ordinary least squares (OLS) and total least squares, thus resolving the bias encountered in TLS alone. Apart from a thorough performance analysis of the novel estimator, a number of applications are presented.},
	doi = {10.1007/3-540-45783-6_56},
	author = {Christoph S. Garbe and Hagen Spies and Bernd J{\"a}hne},
	editor = {Luc Van Gool}
}
@article {spies2002d,
	title = {Range flow estimation.},
	journal = {Computer Vision and Image Understanding},
	volume = {85},
	number = {3},
	year = {2002},
	pages = {209--231},
	abstract = {We discuss the computation of the instantaneous 3D displacement vector fields of deformable surfaces from sequences of range data. We give a novel version of the basic motion constraint equation that can be evaluated directly on the sensor grid. The various forms of the aperture problem encountered are investigated and the derived constraint solutions are solved in a total least squares (TLS) framework. We propose a regularization scheme to compute dense full flow fields from the sparse TLS solutions. The performance of the algorithm is analyzed quantitatively for both synthetic and real data. Finally we apply the method to compute the 3D motion field of living plant leaves.},
	doi = {10.1006/cviu.2002.0970},
	author = {Hagen Spies and Bernd J{\"a}hne and John L. Barron}
}
@conference {spies2001d,
	title = {Accurate optical flow in noisy image sequences},
	booktitle = {ICCV},
	year = {2001},
	pages = {587--592},
	doi = {10.1109/ICCV.2001.937571},
	author = {Hagen Spies and Hanno Scharr}
}
@phdthesis {spies2001,
	title = {Analysing Dynamic Processes in Range Data Sequences},
	year = {2001},
	publisher = {IWR, Fakult{\"a}t f{\"u}r Physik und Astronomie, Univ.\ Heidelberg},
	abstract = {In this thesis a technique to estimate dynamic processes in range data sequences is developed. This includes the instantaneous velocity field (range flow) of a deformable surface and local expansion rates. For the velocity estimation novel differential constraint equations for the depth and intensity data are introduced. These constraint equations are then combined in a general total least squares parameter estimation framework. It turns out that this method can be used for a much broader class of problems where the parameters describing dynamic changes in multi-dimensional data are to be estimated. In addition to a confidence measure does the algorithm yield type measures indicating whether and to what degree there are linear dependencies in the data. Due to these dependencies the full parameter (range flow) set can usually not be computed at all observed data points. To overcome this a special regularisation scheme is developed that makes use of the determined local data structure. Surface expansion rates can then be computed locally from such regularised range flow fields. After an accuracy analysis of the presented algorithms they are applied to study living castor bean leaves. It is shown that this method can be used to investigate the movement and growth of such leaves with high spatial and temporal resolution.},
	url = {http://www.ub.uni-heidelberg.de/archiv/1665},
	author = {Hagen Spies}
}
@incollection {barron2001,
	title = {The fusion of image and range flow},
	year = {2001},
	pages = {174--192},
	publisher = {Springer},
	doi = {10.1007/3-540-45134-X_13},
	author = {John L. Barron and Hagen Spies},
	editor = {R. Klette and Huang, T. and Gimel{\textquoteright}farb, G.}
}
@conference {spies2001b,
	title = {A general framework for image sequence processing},
	booktitle = {Fachtagung Informationstechnik},
	year = {2001},
	pages = {125--132},
	author = {Hagen Spies and Bernd J{\"a}hne}
}
@conference {kirchgessner2001,
	title = {Root Growth Analysis in Physiological Coordinates},
	booktitle = {International Conference on Image Analysis and Processing (ICIAP{\textquoteright}01)},
	year = {2001},
	author = {Norbert Kirchge{\ss}ner and Hagen Spies and Hanno Scharr and Ulrich Schurr}
}
@conference {kirchgessner2001a,
	title = {Root Growth Measurements in Object Coordinates},
	booktitle = {Proceedings of the 23th DAGM Symposium on Pattern Recognition},
	year = {2001},
	publisher = {Springer},
	organization = {Springer},
	doi = {10.1007/3-540-45404-7_31},
	author = {Norbert Kirchge{\ss}ner and Hagen Spies and Hanno Scharr and Ulrich Schurr}
}
@conference {spies2001c,
	title = {Surface expansion from range data sequences},
	booktitle = {Proceedings of the 23th DAGM Symposium on Pattern Recognition},
	year = {2001},
	pages = {163--169},
	publisher = {Springer},
	organization = {Springer},
	abstract = {We compute the range flow field, i.e. the 3D velocity field, of a moving deformable surface from a sequence of range data. This is done in a differential framework for which we derive a new constraint equation that can be evaluated directly on the sensor data grid. It is shown how 3D structure and intensity information can be used together in the estimation process. We then introduce a method to compute surface expansion rates from the now available velocity field. The accuracy of the proposed scheme is assessed on a synthetic data set. Finally we apply the algorithm to study 3D leaf motion and growth on a real range sequence.},
	doi = {10.1007/3-540-45404-7_22},
	author = {Hagen Spies and Bernd J{\"a}hne and John L. Barron}
}
@incollection {spies2000e,
	title = {Analyzing particle movements at soil interfaces},
	year = {2000},
	pages = {648--649},
	publisher = {Academic Press},
	chapter = {A20},
	author = {Hagen Spies and Hermann Gr{\"o}ning and Horst Hau{\ss}ecker and Bernd J{\"a}hne and Horst Hau{\ss}ecker}
}
@conference {spies2000b,
	title = {Dense range flow from depth and intensity data},
	booktitle = {ICPR},
	year = {2000},
	pages = {131--134},
	doi = {10.1109/ICPR.2000.905290},
	author = {Hagen Spies and Bernd J{\"a}hne and John L. Barron}
}
@conference {spies2000c,
	title = {Dense structure estimation via regularised optical flow},
	booktitle = {VMV 2000},
	year = {2000},
	pages = {57--64},
	publisher = {Aka GmbH, Berlin},
	organization = {Aka GmbH, Berlin},
	author = {Hagen Spies and Norbert Kirchge{\ss}ner and Hanno Scharr and Bernd J{\"a}hne},
	editor = {Girod, G. and Greiner, G. and Hans-Peter Seidel and H. Niemann}
}
@conference {spies2000,
	title = {Material transport and structure changes at soil-water interfaces},
	booktitle = {Filters and Drainage in Geotechnical and Environmental Engineering},
	year = {2000},
	pages = {91--97},
	author = {Hagen Spies and Horst Hau{\ss}ecker and H.-J. K{\"o}hler}
}
@incollection {haussecker2000c,
	title = {Motion},
	year = {2000},
	pages = {347--395},
	publisher = {Academic Press},
	chapter = {10},
	author = {Horst Hau{\ss}ecker and Hagen Spies and Bernd J{\"a}hne},
	editor = {Hau\DFecker, H.}
}
@conference {barron2000,
	title = {Optical and range flow to measure 3D plant growth and motion},
	booktitle = {Image Vision Computing New Zealand},
	year = {2000},
	pages = {68--77},
	author = {John L. Barron and Liptay, A. and Hagen Spies}
}
@conference {barron2000a,
	title = {Quantitative regularized range flow},
	booktitle = {Vision Interface},
	year = {2000},
	pages = {203--210},
	author = {John L. Barron and Hagen Spies}
}
@conference {spies2000a,
	title = {Regularised range flow},
	booktitle = {European Conference on Computer Vision (ECCV)},
	volume = {2},
	year = {2000},
	pages = {785--799},
	publisher = {Springer},
	organization = {Springer},
	abstract = {Extending a differential total least squares method for range flow estimation we present an iterative regularisation approach to compute dense range flow fields. We demonstrate how this algorithm can be used to detect motion discontinuities. This can can be used to segment the data into independently moving regions. The different types of aperture problem encountered are discussed. Our regularisation scheme then takes the various types of flow vectors and combines them into a smooth flow field within the previously segmented regions. A quantitative performance analysis is presented on both synthetic and real data. The proposed algorithm is also applied to range data from castor oil plants obtained with the Biris laser range sensor to study the 3-D motion of plant leaves.},
	doi = {10.1007/3-540-45053-X_50},
	author = {Hagen Spies and Bernd J{\"a}hne and John L. Barron},
	editor = {Vernon, D.}
}
@incollection {spies1999,
	title = {Analyzing particle movements at soil interfaces},
	volume = {3: Systems and Applications},
	year = {1999},
	pages = {699-718},
	publisher = {Academic Press},
	chapter = {32},
	author = {Hagen Spies and Oliver Beringer and Hermann Gr{\"o}ning and Horst Hau{\ss}ecker and Bernd J{\"a}hne and Horst Hau{\ss}ecker and Peter Gei{\ss}ler}
}
@conference {spies1999a,
	title = {Differential range flow estimation},
	booktitle = {Proceedings of the 21th DAGM Symposium on Pattern Recognition},
	year = {1999},
	note = {DAGM award},
	pages = {309--316},
	doi = {10.1007/978-3-642-60243-6_36},
	author = {Hagen Spies and Horst Hau{\ss}ecker and Bernd J{\"a}hne and John L. Barron}
}
@conference {koehler1999,
	title = {Fluidisation and deformation of submerged soil due to fluctuating water level},
	booktitle = {XII Europ. Conference on Soil Mechanics and Geotechnical Engineering},
	year = {1999},
	pages = {1109--1115},
	author = {H.-J. K{\"o}hler and Hagen Spies and Oliver Beringer and Horst Hau{\ss}ecker}
}
@incollection {haussecker1999c,
	title = {Motion},
	volume = {2: Signal Processing and Pattern Recognition},
	year = {1999},
	pages = {309--396},
	publisher = {Academic Press},
	chapter = {13},
	author = {Horst Hau{\ss}ecker and Hagen Spies and Bernd J{\"a}hne and Peter Gei{\ss}ler and Horst Hau{\ss}ecker}
}
@conference {haussecker1999a,
	title = {A total least squares framework for low-level analysis of dynamic scenes and processes},
	booktitle = {Proceedings of the 21th DAGM Symposium on Pattern Recognition},
	year = {1999},
	note = {DAGM award},
	pages = {240--249},
	publisher = {Springer},
	organization = {Springer},
	doi = {10.1007/978-3-642-60243-6_28},
	author = {Horst Hau{\ss}ecker and Christoph S. Garbe and Hagen Spies and Bernd J{\"a}hne}
}
@mastersthesis {spies1998,
	title = {Bewegungsdetektion und Geschwindigkeitsanalyse in Bildfolgen zur Untersuchung von Sedimentverlagerungen und Porenstr{\"o}mungen},
	year = {1998},
	school = {University of Heidelberg},
	author = {Hagen Spies}
}
@conference {jaehne1998b,
	title = {Study of dynamical processes with tensor-based spatiotemporal image processing techniques},
	booktitle = {ECCV 1998},
	volume = {1407},
	year = {1998},
	pages = {322--336},
	publisher = {Springer},
	organization = {Springer},
	abstract = {Image sequence processing techniques are used to study exchange, growth, and transport processes and to tackle key questions in environmental physics and biology. These applications require high accuracy for the estimation of the motion field since the most interesting parameters of the dynamical processes studied are contained in first-order derivatives of the motion field or in dynamical changes of the moving objects. Therefore the performance and optimization of low-level motion estimators is discussed. A tensor method tuned with carefully optimized derivative filters yields reliable and dense displacement vector fields (DVF) with an accuracy of up to a few hundredth pixels/frame for real-world images. The accuracy of the tensor method is verified with computer-generated sequences and a calibrated image sequence. With the improvements in accuracy the motion estimation is now rather limited by imperfections in the CCD sensors, especially the spatial nonuniformity in the responsivity. With a simple two-point calibration, these effects can efficiently be suppressed. The application of the techniques to the analysis of plant growth, to ocean surface microturbulence in IR image sequences, and to sediment transport is demonstrated.},
	doi = {10.1007/BFb0054750},
	author = {Bernd J{\"a}hne and Horst Hau{\ss}ecker and Hanno Scharr and Hagen Spies and Dominik Schmund and Ulrich Schurr}
}
@conference {haussecker1998a,
	title = {Tensor-based image sequence processing techniques for the study of dynamical processes},
	booktitle = {Proc. Intern. Symp. On Real-time Imaging and Dynamic Analysis},
	year = {1998},
	pages = {704--711},
	publisher = {International Society of Photogrammetry and Remote Sensing, ISPRS, Commision V},
	organization = {International Society of Photogrammetry and Remote Sensing, ISPRS, Commision V},
	author = {Horst Hau{\ss}ecker and Hagen Spies and Bernd J{\"a}hne}
}
