

\begin{thebibliography}{AabBCD4}


\bibitem[AhS]{AhS}N. Ahuja and B. Schachter.
{\em Pattern Models.}  Wiley, New York 1983.

\bibitem[Ale]{Ale}P.S. Aleksandrov.
{\em Combinatorial Topology.} Vol. 1, chap. 2, Graylock Press NY, 1956.

\bibitem[AlvLM]{AlvLM}L. Alvarez, P.L. Lions and J.M. Morel.
{\em Image selective smoothing and edge detection by nonlinear diffusion (II).} Cahiers de Math\'ematiques de la D\'ecision, \num 9046, CEREMADE, Univ. Paris-IX Dauphine.

\bibitem[Amb]{Amb}L. Ambrosio.
{\em A compactness theorem for a special class of functions of bounded variation.} Boll. Un. Mat. Ital. (to appear).

\bibitem[AmbDeG]{AmbDeG}E. De Giorgi, and L. Ambrosio. 
{\em Un nuovo tipo di funzionale del calcolo delle variazioni.} To appear in  Atti Acad. Naz. Lincei Rend. Cl. Sci. Fis. Mat. Natur.

\bibitem[AmbT]{AmbT}L. Ambrosio, and V. M. Tortorelli.
{\em Approximation of functionals depending on jumps by elliptic functionals via G-convergence.} Preprint. Scuola Normale Superiore di Pisa.

\bibitem[AmiTW]{AmiTW}A. Amini, S. Tehrani and T. E. Weymouth.
{\em Using dynamic programming for minimizing the  energy of active contours in the presence of hard constraints.} Second International Conference on Computer Vision (Proceedings of), ICCV'88, IEEE \num 883.

\bibitem[AsB]{ASB}H. Asada and M. Brady.
{\em The curvature primal sketch.} IEEE Trans. PAMI 8(1), 2-14, 1986.

\bibitem[Az1]{Az1}R. Azencott.
{\em Synchronous Boltzmann machines and Gibbs fields; Learning algorithms.} To appear, Springer Verlag 1989, (NATO Series, Les Arcs Congress Proceedings).

\bibitem[Az2]{Az2}R. Azencott.
{\em Boltzmann Machines : high order interactions and
synchronous learning.} Submitted to IEEE PAMI Trans.

\bibitem[BabWBD]{BabWBD}J. Babaud, A. Witkin, A. Baudin and R. Duda.
{\em Uniqueness of the gaussian kernel for scale-space filtering.} IEEE Trans. PAMI 8, January 1986.

\bibitem[Baj]{Baj}R. Bajcsy.
{\em  Computer identification of visual surfaces.} Computer Graphics and Image Processing, 2, 118-130, 1973.

\bibitem[BajLL]{BajLL}R. Bajcsy, S.W. Lee and A. Leonardis.
{\em Color image segmentation with detection of highlights and local illumination induced by inter-reflections.} IEEE Proc. 10th Int. Conf. on Pattern Recognition (I), 785-790, Atlantic City 1990.

\bibitem[BajR]{BajR}R. Bajcsy and D.A. Rosenthal.
{\em Visual and conceptual focus of attention.}   in Structured Computer Vision, 133-149,  S. Tanimoto and A. Klinger eds, New York, Academic, 1980.

\bibitem[BajSG]{BajSG}R. Bajcsy, F. Solina and A. Gupta.
{\em Segmentation versus object representation-are they separable ?} Chapter in {\em Analysis and interpretation of range images.} R. Jain and A.K. Jain eds, Springer Verlag, New York, 1990.

\bibitem[BajT]{BajT}R. Bajcsy and M. Tavakoli.
{\em Computer recognition of roads from satellite pictures.} IEEE Trans. Syst., Man, Cybern., SMC-6(9), 623-637, 1976.

\bibitem[BalB]{BalB}D.H. Ballard and C.M. Brown.
{\em Computer Vision.} Englewood Cliffs, NJ, Prentice Hall 1982.

\bibitem[BarD]{BarD}M.F. Barnsley and S. Demko.
{\em Iterated function schemes and the global construction of Fractals.} Proc.R.Soc.London. Ser.A 399,1985,p.243-275.

\bibitem[BeaG]{BeaG}J.M. Beaulieu and M. Goldberg.
{\em Hierarchy in picture segmentation : a stepwise optimization approach.}     IEEE PAMI, 11(2), February 1989.

\bibitem[Bec1]{Bec1}J. Beck.
{\em Similarity grouping and peripheral discriminability under uncertainty.}      American Journal of Psychology, 85, 1-19, 1972.

\bibitem[Bec2]{Bec2}J. Beck.
{\em Organization and representation in perception.} Chapter in {\em Textural segmentation}, Erlbaum, Hillsdale, NJ, 1982.

\bibitem[BecPR]{BecPR}J. Beck, K. Prazdny and A. Rosenfeld.
{\em A theory of textural segmentation.} Human and Machine Vision, J.Beck, B. Hope and A. Rosenfeld eds., New York Academic Press, 1983, 1-38.

\bibitem[BecSI]{BecSI}J. Beck, A. Sutter and R. Ivry.     
{\em Spatial frequency channels and perceptual grouping in texture segregation. }    Computer Vision, Graphics and Image Processing, 37, 299-325, 1987.

\bibitem[BenB]{BenB}P. Bennett and M.S. Banks.
{\em Sensitivity loss in odd-symmetric mechanisms and phase anomalies in peripheral vision.}    Nature, 326, 873-876, 1987.

\bibitem[BenH]{BenH}B.M. Bennett and D.D. Hoffman.
 Chapter in {\em Image Understanding}. 1985-1986,  W. Richards and S. Ullman eds, Ablex Publishing Corporation, Norwood, NJ, 1987.

\bibitem[BergenA]{BergenA}J.R. Bergen and E.H. Adelson.
{\em Early vision and texture perception.}  Nature, 333, 363-364, 26 May 1988.

\bibitem[BergenJ1]{BergenJ1}J.R. Bergen and B. Julesz.
{\em Textons, the fundamental elements of preattentive vision and perception of textures.} Bell System Techical Journal, 62(6), 1619-1645, 1983.

\bibitem[BergenJ2]{BergenJ2}J. Bergen and B. Julesz.
{\em Rapid discrimination of visual patterns.}  IEEE Trans. on Systems, Man, and Cybernetics, 13 (5), 1983.

\bibitem[BergerM]{BergerM}M.O. Berger and R. Mohr.
{\em Towards autonomy in active contour models.}  IEEE Proc. 10th Int. Conf. on Pattern Recognition (I), 847-851, Atlantic City 1990.

\bibitem[Berz]{Berz}V. Berzins.
{\em Accuracy of Laplacian edge detectors.}     Computer Graphics and  Image Processing, 27, 195-210, 1984.

\bibitem[Besi1]{Besi1}A.S. Besicovitch.
{\em On the fundamental geometrical properties of linearly measurable plane sets of points.} Math.Ann. vol. 98,1928,p.422-464.

\bibitem[Besi2]{Besi2}A.S. Besicovitch.
{\em On the fundamental geometrical properties of linearly measurable plane sets of points II.} Math.Ann. vol. 115,1938,p.296-329.

\bibitem[Besi3]{Besi3}A.S. Besicovitch.
{\em On the fundamental geometrical properties of linearly measurable plane sets of points III.} Math.Ann. vol. 116,1939,p.349-357.

\bibitem[Besl]{Besl}P.J. Besl.
{\em Surfaces in range image understanding.} Springer Verlag 1988.

\bibitem[BeslJ]{BeslJ}P.J. Besl and R. Jain.
{\em Segmentation through variable-order surface fitting.} IEEE PAMI, 10, \num2, 167-192, March 1988.

\bibitem[BevGKHR]{BevGKHR}J.R. Beveridge, J. Griffith, R.R. Kohler, A.R. Hansen and E.M. Riseman.
{\em Segmenting images using localized histograms and region merging.} Tech. Report 87-88, Dept. of Computer and Information Science, Univ. of Massachusetts, Amherst, 1987.

\bibitem[Bh]{Bh}B. Bhanu.
{\em Representation and shape matching of 3-D objects.} IEEE PAMI 6(3) 340-350, May 1984.

\bibitem[Bi1]{Bi1}T.O. Binford.     
{\em Inferring surfaces from images.} Artificial Intelligence, 17, 205-244, 1981.

\bibitem[Bi2]{Bi2}T.O. Binford.
{\em Survey of model-based image systems.} International Journal of Robotics Research, 1(1), 18-64, Spring 1982.

\bibitem[BlakZ]{BlakZ}A. Blake and A. Zisserman.
{\em Visual Reconstruction.} MIT Press, 1987.

\bibitem[BlatM1]{BlatM1}J. Blat and J.M. Morel.
{\em Variational approach in image processing.} Departemento de Matem\'atica Aplicada de la Universidad Complutense de Madrid.

\bibitem[BlatM2]{BlatM2}J. Blat, and JM. Morel. 
{\em Elliptic problems in image segmentation and their relation to fracture theory.} Proceedings of the Int. Conf. on nonlinear elliptic and parabolic problems, Nancy 88  (Longman  89).

\bibitem[Bod]{Bod}M. Boden.
{\em Computer models of mind.} Cambridge University Press 1987.

\bibitem[BolF]{BolF}R.C. Bolles and M. A. Fischler.
{\em A paradigm for model fitting with applications to image analysis and automated cartography.} Comm. ACM, 24(6), 381-395, June 1981.

\bibitem[BorP]{BorP}A. Borsellino and T. Poggio.
{\em Correlation and convolution algebras.} Kybernetic, 13, 113-122, 1973.  

\bibitem[BovCG]{BovCG}A.C. Bovik, M. Clark and W. S. Geisler.
{\em Computational texture analysis using localized spatial filtering.}     IEEE 1987.

\bibitem[BracS]{BracS}R. Bracho and A.C. Sanderson.
{\em Segmentation of images based on intensity gradient information.}  Proc. CVPR-85, 341-347, 1985.

\bibitem[Brad1]{Brad1}M. Brady.
{\em Computational approaches to Image Understanding.} ACM Comput. Surveys, 14(1), 3-71, March 1982.

\bibitem[Brad2]{Brad2}M. Brady.
{\em Criteria for representation of shape.} Chapter in {\em Human and Machine Vision}, Beck and al. eds,  Academic Press, New York-Orlando,
FL, 1983.

\bibitem[Bro]{Bro}Ph. Brodatz.
{\em Textures for artists and designers.} Dover Publications Inc.  NY 1966.

\bibitem[BriF]{BriF}C. Brice and C. Fennema.
{\em Scene analysis using regions.} Artificial Intelligence,  1, 205-226, 1970.

\bibitem[Bro]{Bro}M.J. Brooks.
{\em Rationalizing edge detectors.} Computer Graphics and Image Processing, 8, 277-285, 1978.

\bibitem[Cae]{Cae}T. Caelli.
{\em Three processing characteristics of visual texture segmentation.}     Spatial Vision, 1(1), 19-30, 1985.

\bibitem[Can]{Can}J. Canny.
{\em A computational approach to edge detection.} IEEE Trans. PAMI 8(6) 679-698, 1986.

\bibitem[CarDeGL]{CarDeGL}M. Carriero, E. DeGiorgi and A. Leaci.
{\em Existence theorem for a minimum problem with free discontinuity set.} Arch. Rat. Mech. Anal., vol. 108, 1989.

\bibitem[CarLPP]{CarLPP}M. Carriero, D. Leaci, E. Pallara and E. Pascali.
{\em Euler conditions for a minimum problem with discontinuity surfaces.} Preprint  Universita degli studi di Lecce (Italy)

\bibitem[CatCLM]{CatCLM}F. Catt\'e, T. Coll, P.L. Lions et J.M. Morel.
{\em An integrodifferential equation for edge detection and image restoration.} Preprint CEREMADE 1990, to appear.

\bibitem[Ch]{Ch}D.S. Chen.
{\em A data-driven intermediate level feature extraction algorithm.} IEEE PAMI, 11(7), 749-758, July 1989.

\bibitem[ChGG]{ChGG}Y.G. Chen, Y. Giga and S. Goto.
{\em Uniqueness and existence of viscosity solutions of generalized mean curvature flow equations.} Preprint Hokkaido University, 1989.

\bibitem[CogJ]{CogJ}J.M. Coggins and A.K. Jain.
{\em A spatial filtering approach to texture analysis.}      Pattern Recog. Lett., 3, 195-203, 1985.

\bibitem[Coh]{Coh}A. Cohen.
{\em Ondelettes, analyses multir\'esolutions et filtres miroir en quadrature.} Ann. Inst. Henri Poincar\'e, Analyse non lin\'eaire, Vol. 7, \num5, p.439-459, 1990.

\bibitem[CohDF]{CohDF}A. Cohen, I. Daubechies and J.C. Feauveau.
{\em Biorthogonal  bases of compactly supported wavelets.} Preprint Bell Labs, 1989.

\bibitem[CohF]{CohF}A. Cohen and J. Froment.
{\em A mathematical and practical analysis of image compression by wavelet transform.} To appear.

\bibitem[CohVSG]{CohVSG}L. Cohen, L. Vinet, P. T. Sander and A. Gagalowicz.
{\em Hierarchical region based stereo matching.} Preprint, INRIA-Rocquencourt.

\bibitem[CongT1]{CongT1}G. Congedo and I. Tamanini.
{\em On the existence of solutions to a problem in image segmentation.} Preprint, Dipartimento di Matematica, Univ. di Trento, 38050 Italy.

\bibitem[CongT2]{CongT2}G. Congedo and I. Tamanini.
{\em Density theorems for local minimizers of area type functionals.} To appear.

\bibitem[ConnH]{ConnH}R.W. Conners and C.A. Harlow.
{\em A theoretical comparison of texture
algorithms. }    IEEE Trans. PAMI 2(3), 204-222, 1980.

\bibitem[Cu]{Cu}S.R. Curtis.
{\em Reconstruction of multidimensional signals from zero-crossings.}     Res. Lab. Electron., MIT, Cambridge, Tech. Rep. 509, 1985.

\bibitem[D'AJ]{D'AJ}F. D'Astous and M.E. Jernigan.
{\em Texture discrimination based on detailed measures of the power spectrum.} Proc. 7th Internat. Conf. Pattern Recog., 83-86, 1984.

\bibitem[DalMMS1]{DalMMS1}G. Dal Maso, J.M. Morel and S. Solimini.
{\em Une approche variationnelle en traitement d'images : r\'esultats d'existence et d'approximation.} C.R. Acad. Sci. Paris, t.308, S\'erie I, p. 549-554, 1989.

\bibitem[DalMMS2]{DalMMS2}G. Dal Maso, J.M. Morel and S. Solimini. 
{\em A variational method in image segmentation: existence and approximation results.} submitted to Acta Matematica.

\bibitem[Daub1]{Daub1}I. Daubechies.
{\em Orthonormal bases of compactly supported wavelets.} Comm. Pure and Applied Math., vol. 41, p.909-996, 1988.

\bibitem[Daub2]{Daub2}I. Daubechies.
{\em Orthonormal bases of compactly supported wavelets.} Part II, II, Preprint Bell Labs, 1989.

\bibitem[DaubJJ]{DaubJJ}I. Daubechies, S. Jaffard and J.L. Journ\'e.
{\em A simple Wilson orthonormal basis with exponential decay.} Preprint Bell Labs, 1989.

\bibitem[Daug1]{Daug1}J.G. Daugman.
{\em Two-dimensional spectral analysis of cortical receptive field profiles.}     Vision Res., 20, 847-856, 1980.

\bibitem[Daug2]{Daug2}J.G. Daugman.
{\em Six formal properties of two-dimensional anisotropic visual filters : structure principles and frequency/orientation selectivity.}    IEEE Trans. Syst., Man, Cybern., 13(5), 1984.

\bibitem[Daug3]{Daug3}J.G. Daugman.
{\em Uncertainty relation for resolution in space, special frequency and orientation optimized by two-dimensional visual cortical filters.}     J. Opt. Soc. Am., A, 2, 1160-1169, 1985.

\bibitem[Dav]{Dav}L. Davis.
{\em A survey of edge detection techniques.} Computer Graphics and Image Processing, 4, 248-270, 1975.

\bibitem[DavCA]{DavCA}L.S. Davis, N. Clearman and J.K. Aggarwal.
{\em An empirical evaluation of generalized co-occurrence matrices.}    IEEE Trans. PAMI 3(2) 214-221, 1981.

\bibitem[De]{De}R. Deriche.
{\em Using Canny's Criteria to derive a recursively implemented optimal edge detector.} Int. J. of Comp. Vision, 167-187, 1987.

\bibitem[DeG]{DeG}E. De Giorgi.
{\em Free discontinuity problems in calculus of variations.} To appear, Proc. of the meeting in J.L. Lions's honour, Paris, 1988.

\bibitem[DeGCL]{DeGCL}E. DeGiorgi, M. Carriero and A. Leaci.
{\em Existence theorem for a minimum problem with free discontinuity set.} Preprint Univ. Lecce, 1988.

\bibitem[Dia]{Dia}J.I. Diaz.
{\em A nonlinear parabolic equation arising in image processing.} Extracta Matematicae, Universidad de Extremadura 1990.

\bibitem[DibK]{DibK}F. Dibos and G. Koepfler.
{\em Propri\'et\'e de r\'egularit\'e des contours d'une image segment\'ee.}  C.R. Acad. Sci. Paris, t. 313, S\'erie I, p. 573-578, 1991.

\bibitem[En]{En}J. Enns.
{\em Seeing textons in context.}  Perception and Psychophysics, 39 (2), 143-147, 1986.

\bibitem[EsG]{EsG}D. Esteban and C. Galand.
{\em Application of QMF to split-band voice coding schemes.} Proc. of Int. Conf. Acoust. Speech, Signal Processing, Harford, 1977.

\bibitem[EvS]{EvS}L.C. Evans and J. Spruck.
{\em Motion of level sets by mean curvature I .} Preprint.

\bibitem[Fal1]{Fal1}K.J. Falconer.
{\em The Geometry of Fractal Sets.} Cambridge University Press,1985.

\bibitem[Fal2]{Fal2}K.J. Falconer.
{\em Fractal Geometry:Mathematical Foundations and Applications.} J.Wiley \& Sons,1990.

\bibitem[FauH]{FauH}O.D. Faugeras and M. Hebert.
{\em The representation, recognition and location of 3-D objects.} Int. J. Robotics Research, 5(3), 27-52, Fall 1986.

\bibitem[Fed]{Fed}H. Federer.
{\em Geometric Measure Theory.} Springer-Verlag,1969.

\bibitem[FelY]{FelJ}J.A. Feldman and Y. Yakimovsky.     
{\em Decision theory and artificial intelligence : 1. A semantics based region analyzer.} Artificial Intelligence, 5, 349-371, 1974.

\bibitem[FiN]{FiN}D. Field and J. Nachmias.
{\em Phase reversal discrimination.} Journal of Vision Research, 24, 333-340, 1984.

\bibitem[FoT]{FoT}I. Fonseca and L. Tartar.
{\em The gradient theory of phase transitions for systems with two potential wells.} Carnegie Mellon Univ.  To appear.

\bibitem[Fre]{Fre}E.C. Freuder.
{\em Affinity : a relative approach to region finding.} Computer Graphics and Image Processing, 5, 254-264, 1976.

\bibitem[Fro]{Fro}J. Froment.
{\em Traitement d'images et applications de la transform\'ee en ondelettes.} Th\`ese Univ. Paris IX Dauphine,  1990

\bibitem[FroM]{FroM}J. Froment and J.M. Morel.
{\em Analyse multi\'echelle, vision st\'er\'eo et ondelettes.} Expos\'e \num 5 du S\'eminaire d'Orsay ``Les ondelettes en 89'', ed. P.G. Lemari\'e, Springer Verlag 1990.

\bibitem[FuM]{FuM}K.S. Fu and J.K. Mui.
{\em A survey on image segmentation.} Pattern Recognition 13, 3-16, 1981.

\bibitem[Gab]{Gab}D. Gabor.
{\em Theory of communication.} J. Inst. Elect. Engr. 93, 429-457, 1946.

\bibitem[GagM]{GagM}A. Gagalowicz and O. Monga.
{\em A new approach for image segmentation.} Proceedings of the Eigth International Conference on Pattern Recognition, Paris, 265-267, IEEE, 1986.

\bibitem[GeiY]{GeiY}JD. Geiger and A. Yuille.
{\em A common framework for image segmentation.} IEEE Proc. 10th Int. Conf. on Pattern Recognition (I), 502-507, Atlantic City 1990.

\bibitem[GemG]{GemG}S. Geman and D. Geman.
{\em Stochastic relaxation, Gibbs distributions and the Baysian restoration of images.} IEEE PAMI 6, 1984.

\bibitem[Gi]{Gi}J. Gillis.
{\em On the projection of irregular linearly measurable plane sets of points.} Fund. Math., 26, p.229-233.

\bibitem[GiGIS]{GiGIS}Y. Giga,S. Goto, H. Ishii and M.H. Sato.
{\em Comparison principle and  convexity preserving properties for singular degenerate parabolic equations on unbounded domains.} Preprint Hokkaido University, 1990.

\bibitem[GoS]{GoS}M. Goldberg and S. Shlien.
{\em A four dimensional histogram approach to the clustering of Landsat-data.} Mach. Process. of Remotely Sensed Data. IEEE CH 1218-7 MPRSD, 250-259, 1977.


\bibitem[Gra]{Gra}R.E. Graham.
{\em Snow removal : A noise-stripping process for TV signals.} IRE Trans. Inf. Theory IT-9, 129-144, 1962.

\bibitem[GraBS]{GraBS}M. Graham, J.  Beck and A. Sutter.
{\em Two nonlinearities in texture segregation.}  Proceedings of the ARVO conference, p161, 1989.

\bibitem[Gri]{Gri}W.E.L. Grimson.
{\em From images to surfaces.} Cambridge, MA, MIT Press 1981.

\bibitem[GriP]{GriP}W.E.L. Grimson and T. Pavlidis.
{\em Discontinuity detection for visual surface reconstruction.} Computer Vision, Graphics, Image Processing, 30, 316-330, 1985.

\bibitem[GroM]{GroM}A. Grossmann and J. Morlet.
{\em Decompositions of Hardy functions into square integrable wavelets of constant shape.} SIAM Journal Math. Anal. 15, (1984), 723-736.

\bibitem[GurB]{GurB}R. Gurnsey and R. Browse.
{\em Micropattern properties and presentation conditions influencing visual texture discrimination.}     Perception and Psychophysics, 41 (3), 239-252, 1987.

\bibitem[Guz]{Guz}A. Guzman.
{\em Decomposition of a visual scene into three dimensional bodies.} Proc. Fall Joint Comp. Conf., 33, 291-304, 1968.

\bibitem[Haa]{Haa}J.A. Haar.
{\em  Zur Theorie der orthogonalen Funktionensysteme.} Math.Ann. 69, (1910), 331-371.

\bibitem[Har1]{Har1}R.M. Haralick.
{\em Statistical and structural approaches to textures.} Proceedings of the IEEE, 67 (5): 786-804, 1979.

\bibitem[Har2]{Har2}R.M. Haralick.
{\em Digital step edges from zero crossing of second directional derivative.} IEEE PAMI, 6, 58-68, 1984. 

\bibitem[HarS]{HarS}R.M. Haralick and L.G. Shapiro.
{\em Image segmentation techniques.} Computer Vision Graphics and Image Processing, 29, 100-132, 1985.

\bibitem[HePB]{HePB}R. von der Heydt, E. Peterhans and G. Baumgartner.
{\em Illusory contours and cortical neuron responses.} Science 224, 1260-1262, 1984.

\bibitem[HolN]{HolN}K. Hollig and J.A. Nohel.
{\em A diffusion equation with a nonmonotone constitutive function.} Proc. on systems of nonlinear PDEs, John Ball ed., Reidel, p. 409-422, 1983.

\bibitem[Horn]{Horn}B. K. P. Horn.
{\em Robot Vision.}  MIT Press  1987.

\bibitem[HornW]{HornW}B.K.P. Horn and E.J. Weldon.
{\em Filtering closed curves.} IEEE Trans. PAMI 8(5), 665-668, 1986.

\bibitem[HoroP1]{HoroP1}S.L. Horowitz and T. Pavlidis.
{\em Picture segmentation by a directed split-and-merge procedure.} Proc. Second Int. Joint Conf. Pattern Recognition, 424-433, 1974.

\bibitem[HoroP2]{HoroP2}S.L. Horowitz and T. Pavlidis.
{\em Picture Segmentation by a Tree Traversal Algorithm.} Journal of the ACM  23, 368-388, 1976.
 
\bibitem[HubW]{HubW}D.H. Hubel and T.N. Wiesel.
{\em Receptive fields, binocular interaction and functional architecture in the cat's visual cortex.}  J. Physiol. 160, 106-154, 1962.

\bibitem[Hue]{Hue}M.H. Hueckel.
{\em A local visual operator which recognizes edges and lines.}    J.A.C.M., 20, 634-647, October 1973.

\bibitem[Hum]{Hum}R.A. Hummel.
{\em Feature detection using basic functions.} Computer Graphics and Image Processing, 9, 40-55, 1979.

\bibitem[HumM]{HumM}R. Hummel and R. Moniot.     
{\em Reconstruction from zero-crossings in scale-space.} IEEE Trans. on Acoustic Speech and Signal Processing. December 1989.

\bibitem[IkU]{IkU}A. Ikonomopoloulos  and M. Unser.
{\em A directional filtering approach to texture discrimination.}     Proc. 7th Internat.  Conf. Pattern Recog. , 87-89, 1984.

\bibitem[JarP]{JaeP}R.A. Jarvis and E.A. Patrick.
{\em Clustering using a similarity measure based on shared near neighbors.} IEEE Trans. Comput. C-22, 1025-1034, 1973.

\bibitem[Ju1]{Ju1}B. Julesz.
{\em Spatial nonlinearities in the instantaneous perception of textures with identical power spectra.}     Phil. Trans. R. Soc. Lond., B290, 83-94, 1980.

\bibitem[Ju2]{Ju2}B.  Julesz.
{\em Textons, the elements of texture perception, and their interactions.} Nature, 290, 12 March 1981.

\bibitem[Ju3]{Ju3}B. Julesz.
{\em Texton gradients : the texton theory revisited.} Biological Cybernetics, 54 : 245-251, 1986.

\bibitem[JuGV]{JuGV}B. Julesz, E.N. Gilbert and J. D. Victor.
{\em Visual discrimination of textures with identical third order statistics.}     Biological Cybernetics, 31, 137-140, 1978.

\bibitem[JuK]{JuK}B. Julesz and B. Kr\"{o}se.
{\em Features and spatial filters.}     Nature, 333, 302-303, May 1988.

\bibitem[Kana]{Kana}T. Kanade.
{\em Region segmentation : signal vs. semantics.} Computer Graphics and Image Processing, 13, 279-297, 1980.

\bibitem[Kani]{Kani}G. Kanizsa.
{\em Organization in Vision.}  New York : Praeger 1979.

\bibitem[KasWT]{KasWT}M. Kass, A. Witkin and D. Terzopoulos.
{\em Snakes: active contour models.} 1st Int.Comp.Vis.Conf. 1987, IEEE \num777.

\bibitem[KatLP]{KatLP}N. Katzir, M. Lindenbaum and M. Porat.
{\em Planar curve segmentation for recognition of partially occluded shapes.}      IEEE Proc. 10th Int. Conf. on Pattern Recognition (I), 842-846, Atlantic City 1990.

\bibitem[KerMWP]{KerMWP}D. Kern, R. Marcus, M. Werman and S. Peleg.
{\em Segmentation by minimum length encoding.}    IEEE Proc. 10th Int. Conf. on Pattern Recognition (I), 681-683, Atlantic City 1990.

\bibitem[KetL]{KetL}R.L. Kettig and D.A. Landgrebe.
{\em Classification of multispectral image data by extraction and classification of homogeneous objects.} IEEE Trans. Geosci. Electron., 14(1), 19-26, 1976.

\bibitem[KjD]{KjD}B.P. Kjell and C.R. Dyer.
{\em Edge separation and orientation texture measures.}  Proc. CVPR-85, 306-311, 1985.

\bibitem[Kn]{Kn}J. K. Knowles.
{\em A note on the energy release rate in quasi-static elastic crack propagation.} SIAM J. Appl. Math.  41(1981), 401-412.

\bibitem[Koen]{Koen}J.J. Koenderink.
{\em The structure of images.}  Biol. Cybern. 50, 1984, 363-370.

\bibitem[KoeMS]{KoeMS}G. Koepfler, J.M. Morel and S. Solimini. 
{\em Segmentation by minimizing a functional and the ``merging'' methods.} Cahiers de Mathematiques de la D\'ecision,\num 9022,1990; presented in september 1991 at the `{\em GRETSI} Colloque' in Juan-les-Pins (France).

\bibitem[Koh]{Koh}R. Kohler.
{\em A segmentation system based on thresholding.} Computer Graphics and Image Processing, 15, 319-338, 1981.

\bibitem[K"oh]{K"oh}W. K\"{o}hler.
{\em Psychologie de la forme.} Id\'ees nrf-Gallimard, 1964.

\bibitem[Kr]{Kr}B.J. Kr\"{o}se.
{\em Local structure analyzers as determinants of preattentive pattern discrimination.}     Biological Cybernetics, 55, 289-298, 1987.

\bibitem[LeBSFB]{LeBSFB}E. Le Bras-Mehlman, M. Schmitt, O.D. Faugeras et J.D. Boissonat.{\em How Delaunay triangulation can be used for representing stereo data.}  ICCV 1988.

\bibitem[Lec]{Lec}Y. Leclerc.
{\em Constructing stable descriptions for image partitioning.} Int.J.C.Vis. 3, 73-102, 1989.

\bibitem[LeeP]{LeeP}D. Lee and T. Pavlidis.
{\em One-dimensional regularization with discontinuities.}     IEEE PAMI, 10, 822-829, November 1988.`

\bibitem[LemM]{LemM}P.G. Lemari\'e et Y. Meyer.
{\em Ondelettes et bases hilbertiennes.} Revista Matematica Iberoamericana, Vol.2, (1986),1-18.

\bibitem[LeoGB]{LeoGB}A. Leonardis, A. Gupta and R. Bajcsy.
{\em Segmentation as the search for the best description of images in terms of primitives.} Technical report \num MS-CIS-90-30, GRASP LAB 215, University of Pennsylvania.

\bibitem[LeuW]{LeuW}J.-G. Leu and W. Wee.
{\em Detecting the spatial structure of natural textures based on shape analysis.} Comput. Vision, Graphics, Image Process.  31, 67-88, 1985.

\bibitem[LevZR]{LevZR}A. Lev, S.W. Zucker and A. Rosenfeld.
{\em Iterative Enhancement of noisy images.} IEEE SMC-7, 435-442, 1977.

\bibitem[LeviL]{LeviL}M.D. Levine and J. Leemet.
{\em A method for non-purposive picture segmentation.} Proc. of the Third International Joint Conference on Pattern Recognition, 1976.

\bibitem[Log]{Log}D. Logan.    
{\em Information in the zero-crossings of band pass signals.} Bell Systems Tech. Journal, 56, 510-, 1977.

\bibitem[Low1]{Low1}D.G. Lowe.
{\em Perceptual Organization and Visual Recognition.} Kluwe Academic Publishers, 1985.

\bibitem[Low2]{Low2}D.G. Lowe.
{\em Organization of smooth image curves at multiple scales.} International Journal of Computer Vision, 3, 119-130, 1989.

\bibitem[MaleBF]{MaleBF}J.T. Maleson, C.M. Brown and J.A. Feldman.
{\em Understanding natural texture.}     Proc. DARPA Image Understanding Workshop, 19-27, October 1977.

\bibitem[Mali]{Mali}J. Malik.
{\em Interpreting line drawings of curved objects.}   International Journal of Computer Vision, 1(1), 73-103, 1987.

\bibitem[MaliP1]{MaliP1}J. Malik and P. Perona
{\em A scale space and edge detection using anisotropic diffusion.} Proc. IEEE Computer Soc. Workshop on Computer Vision, 1987.

\bibitem[MaliP2]{MaliP2}J. Malik and P. Perona.
{\em Preattentive texture discrimination with early vision mechanisms.} Journ. of the Opt. Society. of America. A, 923-932, vol. 7, \num 5, 1991.

\bibitem[Mall]{Mall}S.Mallat.
{\em A theory for multiresolution signal decomposition: the wavelet representation.} IEEE Trans. on Pattern Analysis and Machine Intelligence, 674-693, July 1989.

\bibitem[MallZ]{MallZ}S.G. Mallat and S. Zhong.
{\em Complete signal representation with multiscale edges.} Technical report \num 483, Robotics report \num 219, December 1989, NYU, Computer Science Division, Courant Institute.

\bibitem[Marc]{Marc}S. Marcelja.
{\em Mathematical description of the response of simple cortical cells.} J. Opt. Soc. Am. 70, 1297-1300, 1980.

\bibitem[Marr1]{Marr1}D.Marr.
{\em Early processing of visual information.} Philos. Trans. Roy. Soc. London Ser. B, 275, 483-524, 1976.

\bibitem[Marr2]{Marr2}D. Marr.
{\em Analysing natural images : a computational theory of texture vision.}     Cold Spring Harbor Symposium on Quantitative Biology, XL, 647-662, 1976.

\bibitem[Marr3]{Marr3}D. Marr.
{\em Vision.} Freeman and Co. 1982.

\bibitem[MarrHi]{MarrHi}D. Marr et E. Hildreth. 
{\em Theory of edge detection.}   Proc. Roy. Soc. Lond. B207  1980, 187-217.

\bibitem[MarrP]{MarrP}D. Marr and T. Poggio.
{\em A computational theory of human stereo vision.}    Proc. Roy. Soc. London, B 207, 301-328, 1979.

\bibitem[Marro]{Marro}J.L. Marroquin.
{\em Probabilistic solution of inverse problems.} PhD thesis, MIT Cambridge, MA, September 1985.

\bibitem[Mars]{Mars}C.W. Marshall.
{\em Applied Graph Theory.} John Wiley and Sons, 1971.

\bibitem[Mart]{Mart}
{\em Edge detection using heuristic search methods.} Comp. Graphics Image Processing 1, 169-182, 1972.

\bibitem[MatSN]{MatSN}T. Matsuyama, K. Saburi and M. Nagao.
{\em A structural analyser for regularly arranged textures.}     Comput. Graphics Image Process. 18, 259-278, 1982.

\bibitem[Me]{Me}Y. Meyer.
{\em Ondelettes, fonctions splines et analyses gradu\'ees.} Rapport CEREMADE \num8703, 1987.

\bibitem[Mi]{Mi}D.L. Milgram.
{\em Region extraction using convergent evidence.} Computer Graphics and Image Processing, 11, 1-12, 1979.

\bibitem[MiK]{MiK}D.L. Milgram and D.J. Kahl.
{\em Recursive region extraction.} Computer Graphics and Image Processing, 9, 82-88, 1979.

\bibitem[Mont]{Mont}
{\em On the optimal detection of curves in noisy pictures.} Comm. Assoc. Comput. Mach. 14, 335-345, 1971.

\bibitem[Mod]{Mod}L. Modica.
{\em Gradient theory of phase transitions with boundary contact energy.} Ann. Inst. Poincar\'e,  Vol. 4 \num5 87, pp. 487-512.

\bibitem[MorS1]{MorS1}J.M. Morel and S. Solimini.
{\em Segmentation of images by variational methods: a constructive approach.} Rev. Matematica de la Universidad Complutense de Madrid, Vol.1, \num 1,2,3, 169-182, 1988.

\bibitem[MorS2]{MorS2}J.M. Morel and S. Solimini.
{\em Segmentation of multidimensional data: on the number of regions  obtained by ``split and merge'' methods.} To appear.

\bibitem[MorS3]{MorS3} JM. Morel and S. Solimini.
{\em Segmentation d'images par m\'ethode variationnelle : une preuve constructive d'existence.} C. R. Acad. Sci. Paris S\'erie I, 1988.

\bibitem[MorS4]{MorS4}J.M. Morel and S. Solimini.
{\em Density estimates for the boundaries of optimal segmentations.} To appear.

\bibitem[Mue]{Mue}J.L. Muerle.
{\em Some thoughts on texture discrimination by computer.}  In B.S. Lipkin and A. Rosenfeld (eds), Picture Processing and Psychopictorics,   Academic Press, New York, 371-379, 1970.

\bibitem[MueA]{MueA}J.L. Muerle and D.C. Allen.
{\em Experimental evaluation of techniques for automatic segmentation of objects in a complex scene.} In Pictorial Pattern Recognition, G.C.Cheng and al. eds., pp 3-13, Thompson, Washington, 1968.

\bibitem[MumS1]{MumS1}D. Mumford and J. Shah. 
{\em Boundary detection by minimizing funcionals.} IEEE Conference on Computer Vision and Pattern Recognition,San Francisco 1985.

\bibitem[MumS2]{MumS2}D. Mumford and J. Shah. 
{\em Optimal Approximations by Piecewise Smooth Functions and Associated Variational Problems.} Communications on Pure and Applied Mathematics. vol. XLII No.4, 1989.

\bibitem[MumS3]{MumS3}D. Mumford and J. Shah. 
{\em Boundary detection by minimizing functionals.} Image Understanding, 1988, Ed. S. Ullman and W. Richards.

\bibitem[NahLM]{NahLM}N.E. Nahi and S. Lopez Mora.
{\em Estimation-detection of object boundaries in noisy images.} IEEE Trans. Automat. Control, 23, 834-846, 1978.

\bibitem[NakSS]{NakSS}K. Nakayama, S. Shimojo and G. Silverman.
{\em Stereoscopic depth : its relation to image segmentation, grouping, and the recognition of occluded objects.} Manuscript submitted to Perception, October 1988.

\bibitem[NarLR]{NarLR}K.A. Narayanan and D.P. O'Leary and A. Rosenfeld.
{\em Image smoothing and segmentation by cost minimization.} IEEE Trans. Syst. Man, Cybern. 12(1), 91-96, 1982.

\bibitem[NiM]{NiM}M. Nitzberg and D. Mumford.
{\em The 2.1-D sketch.} Preprint, Department of Mathematics, Harvard University Cambridge MA.

\bibitem[NiS]{NiS}M. Nitzberg and T. Shiota.
{\em Nonlinear image smoothing with edge and corner enhancement.} Technical report \num 90-2, harvard university, Cambridge, MA 01238, 1990.

\bibitem[Nor]{Nor}N.K. Nordstr\"{o}m.
{\em Variational edge detection.}   PhD dissertation, Department of electrical engineering, University of California at Berkeley,
1990.

\bibitem[Not]{Not}H.C. Nothdurft.
{\em Orientation sensitivity and texture segmentation.}  Vision Res., 25, 551-560, 1985.

\bibitem[OhPR]{OhPR}R. Ohlander, K. Price and P.R. Reddy.
{\em Picture segmentation using a recursive region splitting method.} Comput. Graphics Image Process. 8, 313-333, 1978.

\bibitem[OshR]{OshR}S. Osher and L. Rudin.
{\em Feature-oriented image enhancement using shock filters.} SIAM J. on Numerical Analysis, to appear.

\bibitem[OshS]{OshS}S. Osher and J. Setian.
{\em Fronts propagating with curvature dependant speed : algorithms based on the Hamilton-Jacobi formulation.} J. Comp. Physics, 79, 12-49, 1988.

\bibitem[PanR]{PanR}D. P. Panda and A. Rosenfeld.
{\em Image segmentation by pixel classification in (gray level, edge value) space.} IEEE Trans. Comput. C-27, 875-879, 1978.

\bibitem[PapJ]{PapJ}N.T. Pappas and N.S. Jayant.
{\em An adaptive clustering algorithm for image segmentation.} Proc. of ICCV'88, IEEE n$^\circ$ 883, 310-315, 1988.

\bibitem[ParM]{ParM}B. Parvin and G. Medioni.
{\em Segmentation of range images into planar surfaces by split and merge.} Proc. of Computer Vision and Pattern Recognition Conf., IEEE, 1986.

\bibitem[Pav1]{Pav1}T. Pavlidis.
{\em Segmentation of pictures and maps through functional approximation.} Comp.Gr. and Im.Proc. 1, 360-372, 1972.

\bibitem[Pav2]{Pav2}T. Pavlidis.
{\em Structural Pattern Recognition.} Springer, New York 1977.

\bibitem[Pav3]{Pav3}T. Pavlidis.
{\em A critical survey of image analysis methods.} IEEE Proc. of the 8th Int. Conf. on Pattern Recognition, Paris, 1986


\bibitem[PavL]{PavL}T. Pavlidis and Y.T. Liow.
{\em Integrating Region Growing and Edge Detection.} Proc. of the IEEE Conf. Comp. Vision and Patt. Recognition 1988.

\bibitem[Pel]{Pel}S. Peleg.
{\em Classification by discrete optimization.} Computer Vision, Graphics, Image Processing, 25(1), 122-130, 1984.  

\bibitem[PelNHA]{PelNHA}S. Peleg, J. Naor, R. Hartley and D. Avnir.
{\em Multiple resolution texture analysis and classification.}     IEEE Trans. PAMI 6(4), 518-523, 1984.

\bibitem[Pen1]{Pen1}A. Pentland.
{\em Fractal-based description of natural scenes.}     IEEE Trans. PAMI, 6(6), 661-674, 1984.

\bibitem[Pen2]{Pen2}A.P. Pentland.
{\em Automatic extraction of deformable part models.} International Journal of Computer Vision, 4, 107-126, 1990.

\bibitem[Per]{Per}W.A. Perkins.      
{\em Area segmentation of images using edge points.} IEEE PAMI 2(1), January 1980. 

\bibitem[PogTK]{PogTK}T. Poggio, V. Torre and C. Koch.
{\em Computational vision and regularization theory.} Nature, 317, 1985.

\bibitem[PolR]{PolR}D.A. Pollen and S.F. Ronner.
{\em Visual cortical neurones as localized spatial frequency filters.}     IEEE Trans. Syst., Man, Cybern. 13, 907-916, 1983.

\bibitem[PonSWH]{PonSWH}T.C. Pong, L.G. Shapiro, L.T.Watson and R.M. Haralick.
{\em Experiments in segmentation using a facet model region grower.} Computer
Vision and Graphics Image Processing, 25, 1984.

\bibitem[Pra]{Pra}J.M. Prager.
{\em Extracting and labeling boundary segments in natural scenes.} IEEE  PAMI 2(1), 16-27, January 1980.

\bibitem[PreM]{PreM}J.S.M. Prewitt and M.L. Mendelsohn.
{\em The analysis of cell images.} Ann. N.Y. Acad. Sci. 128, 1035-1053, 1966.

\bibitem[Rea]{Rea}T.C. Rearick.
{\em A texture analysis algorithm inspired by a theory of preattentive vision.}     Proc. IEEE Conf. Comput. Vision Pattern Recog., 312-317, San Francisco 1985.

\bibitem[RenHC]{RenHC}I. Rentschler, M. Hubner and T. Caelli.
{\em On the discrimination of compound Gabor signals and textures.}     Vision Research, 28 (2), 279-291, 1988.

\bibitem[Ric]{Ric}T.J. Richardson.
{\em Scale independant piecewise smooth segmentation of images via variational methods.} PhD. Dissertation, Lab. for Information and Decision Systems, MIT, Cambridge MA 02139, February 1990.

\bibitem[RisA]{RisA}E. Riseman and M. Arbib.
{\em Computational techniques in the visual segmentation of static scenes.} Computer Graphics and Image Processing, 6, 221-276, 1977.

\bibitem[Roc]{Roc}I. Rock.
{\em The logic of perception.} Cambridge MA, MIT  Press, 1983.

\bibitem[RosD]{RosD}A. Rosenfeld and L.S. Davis.
{\em Image segmentation and image models.} Proc. IEEE, vol 67(5), 764-772, May 1979.
 
\bibitem[RosHZ]{RosHZ}A. Rosenfeld, R.A. Hummel and S.W. Zucker.
{\em Scene labeling by relaxation operations.} IEEE Trans. Syst., Man, Cybern., SMC-6, 420-433, 1976.
 
\bibitem[RosK]{RosK}A. Rosenfeld and Kak A.C.
{\em Digital picture processing, Computer Science and Applied Mathematics.} Academic Press 1982.

\bibitem[RotL]{RotL}G. Roth and M.D. Levine.
{\em Segmentation of geometric signals using robust fitting.}      IEEE Proc. 10th Int. Conf. on Pattern Recognition (I), 826-831, Atlantic City 1990.

\bibitem[RosT]{RosT}A. Rosenfeld and M. Thurston.
{\em Edge and curve detection for visual scene analysis.} IEEE Trans. Comput. 20, 562-569, 1971.

\bibitem[RuS]{RuS}B. Rubenstein and D. Sagi.
{\em Texture variability across the orientation spectrum can yield asymmetry in texture discrimination.}    European conference on visual perception, 1989.

\bibitem[ScDR]{ScDR}B.J. Schachter, L.S. Davis and A. Rosenfeld.
{\em Some experiments in image segmentation by clustering of local feature values.} Pattern Recognition 11, 19-28, 1978.

\bibitem[Sha1]{Sha1}J. Shah.
{\em Properties of segmentations which minimize energy functionals.} Preprint, Northeastern University, Math. Dept., Boston.

\bibitem[Sha2]{Sha2}J. Shah.
{\em Parameter estimation, multiscale representation and algorithms for energy-minimizing segmentations.}   IEEE Proc. 10th Int. Conf. on Pattern Recognition (I),  815-819, Atlantic City 1990.

\bibitem[Sha'U]{Sha'U}A. Sha'ashua and S. Ullman.
{\em Structural Saliency : the detection of globally salient structures using a locally connected network.} Proc. of the IEEE  2nd International Conference on Computer Vision, Tampa, 1988.

\bibitem[ShanDG]{ShanDG}K.F. Shanmugam, F.M. Dickey and J.A. Green.
{\em An optimal frequency domain filter for edge detection in digital pictures.}    IEEE PAMI 1, 37-49, 1979.

\bibitem[Sim-JC]{Sim-JC}J.C. Simon.
{\em Some current topics in clustering in relation with pattern recognition.} Proc. 4th Int. Joint Conf. on Pattern Recognition, 19-29, 1978.

\bibitem[Si-L]{Si-L}L. Simon.
{\em Lectures on Geometric Measure Theory.} Centre for Math. Analysis. Australian Nat. Univ., vol. 33, 1983.

\bibitem[SnS]{SnS}P.H.A. Sneath and R.R. Sokal.
{\em Numerical taxonomy.} San Francisco CA, Freeman 1973.

\bibitem[Sol]{Sol}S. Solimini.
{\em Notes.} S\'eminaire de Jacques-Louis Lions, Coll\`ege de France, 23 Mars,1990.

\bibitem[Son]{Son}M. Soner.
{\em Motion of a set by curvature of its  mean boundary.} Preprint.

\bibitem[SuBG]{SuBG}A. Sutter, J. Beck and N. Graham.
{\em Contrast and spatial variables in texture segregation : testing a simple spatial frequency channels model.}     Center for Automation Research, Computer Vision Lab., CAR-TR-381, CS-TR-2091, DCR-86-03723, University of Maryland, College Park, 1988.

\bibitem[TamMY]{TamMY}H. Tamura, S. Mori and T. Yamawaki.
{\em Textural features corresponding to visual perception.}   IEEE Trans. Syst., Man and Cybern., 8(6), 460-473, 1978.

\bibitem[TanK]{TanK}S. Tanimoto and A. Klinger.
{\em Structural Computer Vision.} New York : Academic 1980.

\bibitem[Te1]{Te1}D. Terzopoulos.
{\em Multilevel computational processes for visual surface reconstruction.}     Computer Vision, Graphics, and Image Processing, 24, 52-95, 1983.

\bibitem[Te2]{Te2}D. Terzopoulos.
{\em Computing visible-surface representations.}     A.I. Memo 800, MIT Artificial Intelligence Lab., Cambridge MA, March 1985.

\bibitem[Te3]{Te3}D. Terzopoulos.
{\em Regularization of inverse visual problems involving discontinuities.} IEEE PAMI-8,4, July 1986.

\bibitem[TiA]{TiA}A.N. Tikhonov and V.I. Arsenin.
{\em Solutions of Ill-posed problems. }    Washington D.C. : Winston 1977.

\bibitem[TomST]{TomST}F. Tomita, Y. Shirai and S. Tsuji.
{\em Description of textures by a structural analysis.}     Proc. 6th Intern. Joint Conf. Artif. Intell., 884-889, Tokyo 1979.

\bibitem[TorP]{TorP}V. Torre and T.A. Poggio.
{\em On edge detection.}   IEEE PAMI 8(2), 147-163, 1986.  

\bibitem[TouG]{TouG}J.T.  Tou and R.C. Gonzalez.
{\em Pattern Recognition Principles.} Reading, MA : Addison Wesley 1974.

\bibitem[Tr]{Tr}A. Treisman.
{\em Preattentive processing in vision.}  Comput. Vision, Graphics, Image Process., 31(2), 156-177, 1985.

\bibitem[TsT]{TsT}S. Tsuji and F. Tomita.
{\em A structural analyser for a class of textures.}     Comput. Graphics Image Process., 2, 216-231, 1973.

\bibitem[Tu]{Tu}M.R. Turner.
{\em Texture discrimination by Gabor functions.}     Biol. Cybern. 55, 71-82, 1986.

\bibitem[VilNP]{VilNP}F. Vilnrotter, R. Nevatia and K. Price.
{\em Structural analysis of natural textures.}      IEEE Trans. PAMI 8, 76-89, 1986.

\bibitem[Vin]{Vin}L. Vinet.
{\em Segmentation et mise en correspondance de r\'egions de paires d'images st\'er\'eoscopiques.} Th\`ese Univ. Paris IX Dauphine, juillet 1991.

\bibitem[Vis]{Vis}R. Vistnes.    
{\em Texture models and image measures for texture
discrimination.} International Journal of Computer Vision, 3, 313-336,
1989.

\bibitem[VoP1]{VoP1}H. Voorhees and T. Poggio.
{\em  Detecting textons and texture boundaries in natural images.} Proc. Int. Conf. Comp. Vision, IEEE, 250-258, 1987.

\bibitem[VoP2]{VoP2}H. Voorhees and T. Poggio.
{\em Computing texture boundaries from images.} Nature, 333, 364-367, 1988.

\bibitem[Wan]{Wan}Y. Wang.      
{\em } Preprint,  Aiken Lab. , Harvard University.

\bibitem[War]{War}J.H. Ward.
{\em Hierarchical grouping to optimize an objective function.} J. Amer. Stat. Ass. 58, 236-245, 1963.

\bibitem[WebDV]{WebDV}M.A. Webster and R.L. De Valois.
{\em Relationship between spatial-frequency and orientation tuning of straite-cortex cells.}     J. Opt. Soc. Am. 2, 1124-1132, 1985.

\bibitem[WeiB]{WeiB}R. Weiss and M. Boldt.     
{\em Geometric grouping applied to straight lines.} Proc. of  the IEEE Conf. on Computer Vision and Pattern Recognition, 1986.

\bibitem[WermL]{WermL}D. Wermser and C.-E. Liedtke.
{\em Texture analysis using a model of the visual system.}     Proc. 6th Intern. Conf. Pattern Recog., 1078-1080, Munich 1982.

\bibitem[Wert]{Wert}M. Wertheimer.
{\em Untersuchungen zur Lehre von der Gestalt II.} Psychologische Forschung, 4, 301-350, 1923.

\bibitem[WestHLP]{WestHLP}T. Westman, D. Harwood, T. Laitinen and M. Pietikinen.
{\em Color segmentation by hierarchical connected components analysis with image enhancement by symmetric neighbourhood filters.}      IEEE Proc. 10th Int.
Conf. on Pattern Recognition (I), 796-802, Atlantic City 1990.

\bibitem[Wesz]{Wesz} J.S. Weszka.
{\em A survey of threshold selection techniques.} Computer Graphics and Image processing, 7, 259-265, 1978.

\bibitem[Wi1]{Wi1}A.P. Witkin.
{\em Recovering surface shape and orientation from texture.} Artificial Intelligence 17, 17-45, August 1981.

\bibitem[Wi2]{Wi2}A.P. Witkin.
{\em Scale-space filtering.}  Proc. of IJCAI, Karlsruhe 1983, 1019-1021.

\bibitem[YuP1]{YuP1}A.L. Yuille and T. Poggio.
{\em Scaling theorems for zero-crossings.} MIT A.I. Memo 730, 1983.

\bibitem[YuP2]{YuP2}A.L. Yuille and T. Poggio.
{\em Fingerprint theorems for zero-crossings.} MIT, Cambridge, A.I. Memo 730, 1983.

\bibitem[Zu1]{Zu1}S.W. Zucker.
{\em Region growing: Childhood and Adolescence (Survey).} Comp. Graphics and Image Proc. 5, 382-399, 1976.

\bibitem[Zu2]{Zu2}S.W. Zucker.
{\em Algorithms for image segmentation.} in ``Digital Image Processing and Analysis'', ed. J.C. Simon and A. Rosenfeld, 1977.

\bibitem[ZuDDI]{ZuDDI}S.W. Zucker, C. David, A. Dobbins and L. Iverson.
{\em The organization of curve detection : Coarse tangent fields and fine spline coverings.} Proc. 2nd Int. Conf. Computer Vision, 568-577, Tampa, Florida 1988.


\end{thebibliography}
