Showing papers on "Object model published in 1993"

Rapid octree construction from image sequences

Abstract: The construction of a three-dimensional object model from a set of images taken from different viewpoints is an important problem in computer vision. One of the simplest ways to do this is to use the silhouettes of the object (the binary classification of images into object and background) to construct a bounding volume for the object. To efficiently represent this volume, we use an octree, which represents the object as a tree of recursively subdivided cubes. We develop a new algorithm for computing the octree bounding volume from multiple silhouettes and apply it to an object rotating on a turntable in front of a stationary camera. The algorithm performs a limited amount of processing for each viewpoint and incrementally builds the volumetric model. The resulting algorithm requires less total computation than previous algorithms, runs in close to real-time, and builds a model whose resolution improves over time.

Abstracting Object Interactions Using Composition Filters

Abstract: It is generally claimed that object-based models are very suitable for building distributed system architectures since object interactions follow the client-server model. To cope with the complexity of today's distributed systems, however, we think that high-level linguistic mechanisms are needed to effectively structure, abstract and reuse object interactions. For example, the conventional object-oriented model does not provide high-level language mechanisms to model layered system architectures. Moreover, we consider the message passing model of the conventional object-oriented model as being too low-level because it can only specify object interactions that involve two partner objects at a time and its semantics cannot be extended easily. This paper introduces Abstract Communication Types (ACTs), which are objects that abstract interactions among objects. ACTs make it easier to model layered communication architectures, to enforce the invariant behavior among objects, to reduce the complexity of programs by hiding the interaction details in separate modules and to improve reusability through the application of object-oriented principles to ACT classes. We illustrate the concept of ACTs using the composition filters model.

Object oriented distributed computing system processing request to other object model with code mapping by object managers located by manager of object managers

Abstract: An object oriented distributed computing system is provided. Processing means call a location service within automatically generated stubs in response to a request for a service provided by a particular object. The location service is automatically called on behalf of the requester to locate the target object when the request is issued. Multiple Object Managers reflecting multiple Object Models are permitted in the system. Programmers and users do not need to know the Object Model adhered to by an Object Manager. A request to any object in the system is independent of the Object Model of the sought object's Object Manager. A generic interface enables new Object Managers reflecting new Object Models to be easily added to the system. Availability of the target object is independent of association of the target object with a process at the time the request was issued. Deactivation of processes is automatically accomplished in response to the system needing resources.

Visualizing the behavior of object-oriented systems

Abstract: Numerous classes, complex inheritance and containment hierarchies, and diverse patterns of dynamic interaction all contribute to difficulties in understanding, reusing, debugging, and tuning large object-oriented systems. To help overcome these difficulties, we introduce novel views of the behavior of object-oriented systems and an architecture for creating and animating these views. We describe platform-independent techniques for instrumenting object-oriented programs, a language-independent protocol for monitoring their execution, and a structure for decoupling the execution of a subject program from its visualization. Case studies involving tuning and debugging of real systems are presented to demonstrate the benefits of visualization. We believe that visualization will prove to be a valuable tool for object-oriented software development.

CORDIS-ANIMA: a Modeling and Simulation System for Sound and Image Synthesis — The General Formalism

Abstract: CORDIS-ANIMA is a digital, real-time, object modeling and simulation system. The simulated objects can be seen, heard, and manipulated. This system has been built at the ACROE in several stages since 1978. It constitutes the nucleus of a creation tool for computer music (CORDIS) and animated images (ANIMA). The raison d'etre of this tool is to provide reproductions of physical objects from the real world. These objects can be musical instruments (in terms of objects that produce sound vibrations when subjected to some action), or they can be visible objects such as those we observe in the real world. The simulated copy (the simulacrum) of these objects is produced using a programmed digital device that can communicate with human operators through transducers associated with acoustic, visual, and gestural media. The gestural medium is a two- way channel; information can flow from the operator to the object (gestural action) and also from the object to the operator (tactile and kinesthetic feedback). What we seek is total simulation. Such a simulation must restore not only the sensorimotor aspects of the object (the gestural, tactile, acoustic, and visual aspects) but also its structure and behavior. This is not merely a synthesis of the effects produced by the object but a synthesis of the intemal state of the object itself.

System and method for importing and exporting data between an object oriented computing environment and an external computing environment

Abstract: A system and method for importing and exporting data between an object oriented computing environment and an external computing environment encapsulates the validation, conversion, and update control mechanisms for objects in metadata about the objects. Metadata logic operates identically on a variety of internal objects, freeing the object oriented computing environment from the need to duplicate the same control logic for each user interface. During program generation, metadata objects are generated to link an external computing environment data field name, a corresponding object oriented computing environment attribute name and a corresponding external data format for each external data field which is imported and exported. An external class object is defined, including conversion parameters for converting the corresponding object oriented computing environment attribute into the corresponding external data format. External object class metadata objects contain the object oriented computing environment attributes which are used for import and export.

Deterministic, probabilistic and subjective modeling system

Abstract: A modeling system that arranges the model in a hierarchical structure of communicating and independently executing object modules controlled by an overall supervisor. Each object represents a component or a system and includes an object controller which communicates with other object modules, an object error checker and an object model. The objects communicate through a database accessible by all objects. The structure of the object module and the hierarchical structure itself are standardized allowing new components or systems to be added by adding a standard object module which includes an object model that is unique to the object being modeled. The controller for an object causes subobjects upon which the object model depends for data to be executed prior to execution of the object model. Such bottom up model traversal insures that models do not execute until all needed data is available. The error check module checks the controller and model modules to make sure they are executing properly. The object model includes a deterministic equation based component aging model, a statistical based component aging model and expert rules that combine the deterministic and statistical model with the knowledge of experts to determine the current state of the object and make recommendations concerning future actions concerning the object. A maintenance module is also included along side the supervisor that allows maintenance actions for the objects to be taken into consideration.

System and method for controlling versions of objects in an object oriented computing environment

Abstract: A system and method for controlling versions of selected objects in an object oriented computing system includes a common logical key attribute in each version of an object, which is used to identify all versions of an object. The object frame of each version also includes a unique combination of an insert sequence attribute and an extract sequence attribute. The unique combination of insert sequence attribute and extract sequence attribute allows the selection of a unique version of an object based on time. In order to select one or more versions of an identified object, a version time is converted into a selection sequence value. The selection sequence value is then compared to the insert sequence attributes and extract sequence attributes in order to select at least one of the versions of the selected objects. Each version may also include a perspective attribute for providing another selection criteria for selecting one or more versions of an object.

Alignment by maximisation of mutual information

Abstract: A new information-theoretic approach is presented for fi nding the pose of an object in an image. The technique does not require information about the surface properties of the object, besides its shape, and is robust with respect to variations of illumination. In our derivation, few assumptions are made about the nature of the imaging process. As a result the algorithms are quite general and can foreseeably be used in a wide variety of imaging situations. Experiments are presented that demonstrate the approach registering magnetic resonance (MR) images with computed tomography (CT) images, aligning a complex 3D object model to real scenes including clutter and occlusion, tracking a human head in a video sequence and aligning a view-based 2D object model to real images. The method is based on a formulation of the mutual information between the model and the image called EMMA. As applied here the technique is intensity-based, rather than feature-based. It works well in domains where edge or gradient-magnitude based methods have difficulty, yet it is more robust than traditional correlation. Additionally, it has an efficient implementation that is based on stochastic approximation. Finally, we will describe a number of additional real-world applications that can be solved effi ciently and reliably using EMMA. EMMA can be used in machine learning to find maximally informative projections of high-dimensional data. EMMA can also be used to detect and correct corruption in magnetic resonance images (MRI).

Fundamental Concepts of Object Oriented Databases.

Abstract: It is claimed that object oriented databases (OODBs) overcome many of the limitations of the relational model. However, the formal foundation of OODB concepts is still an open problem. Even worse, for relational databases a commonly accepted datamodel existed very early on whereas for OODBs the uniication of concepts is missing. The work reported in this paper contains the results of our rst investigations on a formally founded object oriented datamodel (OODM) and is intended to contribute to the development of a uniform mathematical theory of OODBs. A clear distinction between objects and values turns out to be essential in the OODM. Types and Classes are used to structure values and objects repectively. Then the problem of unique object identiication occurs. We show that this problem can be be solved for classes with extents that are completely representable by values. Such classes are called value-representable. Another advantage of the relational approach is the existence of structurally determined generic update operations. We show that this property can be carried over to object-oriented datamodels if classes are value-representable. Moreover, in this case database consistency with respect to implicitly speciied referential and inclusion constraints will be automatically preserved. This result can be generalized with respect to distinguished classes of explicitly stated static constraints. Given some arbitrary method and some integrity constraint there exists a greatest consistent specialization (GCS) that behaves nice in that it is compatible with the conjunction of constraints. We present an algorithm for the GCS construction of user-deened methods and describe the GCSs of generic update operations that are required herein.

Roles for composite objects in object-oriented analysis and design

Abstract: A method is presented for using composite objects which separates their role and meaning as models of relations between problem-domain concepts from their role and meaning as models of hierarchical sof’twarc structures. The meaning of composite objects is analysed in terms of connections bctwccn real-world concepts in object-oriented analysis and bctwccn software objects in object-oriented design. By capturing the designer’s rationale for model transformation, the resulting models arc casicr to understand and maintain. An embedded systems example illustrates the approach.

Method and system for controlling access to objects in a data processing system

Abstract: A method and system are provided for controlling the access to objects in an object oriented data processing application, where the objects are being hierarchically structured and either locally available or retrievable from an external unit. Each object has a dependent object counter which indicates the existence or the number of dependent objects associated with that object. When at least one dependent object is not locally available, a dummy object is appended to that object, enabling the object expansion even if the dependent objects of the selected object are not yet locally available in local memory. The objects to be retrieved from the external unit are locked from user access, while access is allowed to the locally available dependent objects.

Palette and parts view of a composite object in an object oriented computer system

Abstract: An object-based computer system has a graphical user interface. A palette view is provided onto an object within the system that depicts all the subobjects that potentially form parts of that object. By manipulating the objects in this view, for example by dragging and dropping them onto another view of the object, the user can select them for inclusion in the object. Also provided is a parts view, which depicts the list of parts that have actually been included within the object.

Three-Dimensional Object Recognition Systems

Abstract: Contributors. 3-D object recognition: Inspirations and lessons from biological vision. Range sensing for computer vision. Feature extraction for 3-D model building and object recognition. Three-dimensional surface reconstruction: Theory and implementation. CAD-based object recognition in range images using pre-compiled strategy trees. Active 3-D object models. Image prediction for computer vision. Tools for 3-D object location from geometrical features by monocular vision. Part-based modeling and qualitative recognition. Appearance-based vision and the automatic generation of object recognition programs. Recognizing 3-D objects using constrained search. Recognition of superquadric models in dense range data. Recognition by alignment. Representations and algorithms for 3-D curved object recognition. Structural indexing: efficient three dimensional object recognition. Building a 3-D world model for outdoor scenes from multiple sensor data. Understanding object configurations. Modal descriptions for modeling, recognition, and tracking. Function-based generic recognition for multiple object categories.

Learning object recognition models from images

Abstract: To recognize an object in an image an internal model is required to indicate how that object may appear. The authors show how to learn such a model from a series of training images depicting a class of objects, producing a model that represents a probability distribution over the variation in object appearance. Features identified in an image through perceptual organization are represented by a graph whose nodes include feature labels and numeric measurements. A learning procedure generalizes multiple image graphs to form a model graph in which the numeric measurements are characterized by probability distributions. A matching procedure, using a similarity metric based on a non-parametric probability density estimator, compares model and image graphs to identify an instance of a modeled object in an image. Experimental results are presented from a system constructed to test this approach. The system learns to recognize partially occluded 2-D objects in 2-D images using shape cues. It can recognize objects as similar in general appearance while distinguishing them by their detailed features. >

Maintaining information about persistent replicated objects in a distributed system

Abstract: Presents a general model for persistent replicated object management and identify what metainformation about objects needs to be maintained by a naming and binding service to ensure that objects named by application programs are bound to only those object replicas which are in a mutually consistent state. These ideas are developed within the framework of a distributed system in which application programs are composed of atomic actions (atomic transactions) manipulating persistent (long-lived) objects. >

Positioning for multiple icons in an object-oriented interface

Abstract: A method, system and program for creating child graphical objects in an object oriented graphical user interface. First, the child object is created by copying a set of attributes from a parent graphical object to a memory partition allocated to the first child graphical object. This operation is typically called inheritance or subclassing in object oriented programming. Next, the location data of the first child graphical object is automatically changed from those copied from the parent graphical object. Next, the parent and child graphical objects are displayed on a display in the graphical user interface, the child graphical object being offset in location from the parent graphical object.

Local search algorithms for geometric object recognition: optimal correspondence and pose

Abstract: Recognizing an object by its shape is a fundamental problem in computer vision, and typically involves finding a discrete correspondence between object model and image features as well as the pose--position and orientation--of the camera relative to the object. This thesis presents new algorithms for finding the optimal correspondence and pose of a rigid 3D object. They utilize new techniques for evaluating geometric matches and for searching the combinatorial space of possible matches. An efficient closed-form technique for computing pose under weak-perspective (four parameter 2D affine) is presented, and an iterative non-linear 3D pose algorithm is used to support matching under full 3D perspective. A match error ranks matches by summing a fit error, which measures the quality of the spatial fit between corresponding line segments forming an object model and line segments extracted from an image, and an omission error, which penalizes matches which leave portions of the model omitted or unmatched. Inclusion of omission is crucial to success when matching to corrupted and partial image data. New optimal matching algorithms use a form of combinatorial optimization called local search, which relies on iterative improvement and random sampling to probabilistically find globally optimal matches. A novel variant has been developed, subset-convergent local search finds optimal matches with high probability on problems known to be difficult for other techniques. Specifically, it does well on a test suite of highly fragmented and cluttered data, symmetric object models, and multiple model instances. Problem search spaces grows exponentially in the number of potentially paired features n, yet empirical performance suggests computation is bounded by $n\sp2.$ Using the 3D pose algorithm during matching, local search solves problems involving significant amounts of 3D perspective. No previous work on geometric matching has generalized in this way. Our hybrid algorithm combines the closed-form weak-perspective pose and iterative 3D pose algorithms to efficiently solve matching problems involving perspective. For robot navigation, this algorithm recognizes 3D landmarks, and thereby permits a mobile robot to successfully update its estimated pose relative to these landmarks.

The model, language, and implementation of an object-oriented multimedia knowledge base management system

Abstract: New applications such as CAD, AI, and hypermedia require direct representation and flexible use of complex objects, behavioral knowledge, and multimedia data. To this end, we have devised a knowledge base management system called Jasmine. An object-oriented approach in a programming language also seems promising for use in Jasmine. Jasmine extends the current object-oriented approach and provides the following features. Our object model is based on functional data models and well-established set theory. Attributes or functions composing objects can represent both structural and behavioral knowledge. The object model can represent incomplete and generic knowledge. The model can support the basic storage and operations of multimedia data. The facets of attributes can flexibly represent constraints and triggers. The object manipulation language can support associative access of objects. The structural and behavioral knowledge can be uniformly treated to allow the user to specify complex object operations in a compact manner. The user-defined and system-defined attributes can be uniformly specified to ease user customization of the language. The classes and instances can be uniformly accessed. Incomplete knowledge can be flexibly accessed. The system has a layered architecture. Objects are stored in nested relations provided by extensive DBMS as a sublayer. User query of objects is compiled into relational operations such as select and join, which can be efficiently processed using hashing. The behavioral knowledge is compiled into predicate and manipulation function interfaces that can directly access tuples in a buffer.—Authors' Abstract

Learning object models from appearance

Abstract: We address the problem of automatically learning object models for recognition and pose estimation. In contrast to the traditional approach, we formulate the recognition problem as one of matching visual appearance than shape. The appearance of an object in a two-dimensional image depends on its shape, reflectance properties, pose in the scene, and the illummation conditions. While shape and reflectance are intrinsic properties of an object and are constant, pose and illumination vary from scene to scene. We present a new compact representation of object appearance that is parametrized by pose and illumination. For each object of interest, a large set of Images is obtained by automatically varying pose and illumination. This large image set is compressed to obtain a low-dimensional subspace, called the eigenspace, in which the object is represented as a hypersurface. Given an unknown input image, the recognition system projects the image onto the eigenspace. The object is recognized based on the hypersurface it lies on. The exact position of the projection on the hypersurface determines the object's pose in the image. We have conducted experiments usmg several objects with complex appearance characteristics. These results suggest the proposed appearance representation to be a valuable tool for a variety of machine vision applications.

UFO: uncertainty and fuzziness in an object-oriented model

Abstract: The authors present a method for coping with the uncertainty and fuzziness that cause problems in handling information. As these two concepts carry different semantic meanings, they distinguish between them by representing fuzzy information as conjunctive fuzzy sets and uncertainty by means of generalized fuzzy sets. An object-oriented methodology is chosen because it offers an excellent framework for handling uncertainty in a way completely transparent to the user. This treatment of uncertainty in a fuzzy object-oriented environment is well-suited to databases; hence examples from this field are selected. Genealogical databases, where uncertain information is very common, and where information is continuously updated, are used as a frame of reference. The proposed model also allows storage of as much information about uncertain objects as possible. >

Weaving a Web: the Structure and Creation of an Object Network Representing an Electronic Reference Work.

Abstract: For the improvement of large-scale electronic publications, such as encyclopaedic reference works,we propose an object-oriented document model that in addition to the SGML-structured text corpus represents other access structures, in particular a fine-grained, highly structured, tightly interconnected network of domain-specific objects and facts. The paper presents strategies and tools for efficient acquisition of the desired object network into an Editor’s Workbench. The application context is the Dictionary of Art, to be published as a print edition by Macmillan Publishers Ltd. in 1996.

Sequentially navigated object oriented computer system

Abstract: An object based computer system has viewers which may be directed around the object world of the system between semantic objects. The system includes a sequence object that has a path list specifying a path around a sequence of semantic objects of system. Each viewer can be linked to the sequence object to access the path list held by the latter, thereby enabling the viewer to follow the corresponding sequence of semantic objects, viewing each in turn.

References to remote mobile objects in Thor

Abstract: Thor is a distributed object-oriented database where objects are stored persistently at highly available servers called object repositories, or ORs. In a large Thor system, performance tuning and system reconfiguration dictate that objects must be able to migrate among ORs. The paper describes two schemes for object references that support object migration, one using location-independent names and the other, location-dependent names. The paper analyzes the performance of the two schemes and concludes that location-dependent names are the right choice for systems like Thor, where we want fast access to objects that have migrated.

Towards a Formal Approach for Object Database Design

Abstract: 1 Introduction This paper focuses on a formal approach* for advanced database modeling and design. It is based on the IF02 model, an extension of the semantic model IF0 defined by S. Abiteboul and R. Hull. It preserves the acquired strengths of the semantic approaches, whilst integrating concepts of the object paradigm. To model an IF02 schema, the structural part of the model including concepts such as alternative, composition, grouping for building complex objects and semantic constraints is formally specified. Furthermore, the definitions of update facilities necessary to modify and perfect IF02 schemas are specified through change rules. Finally, in order to design a database schema, an IF02 schema is translated, in an automatical way, into an existing target (implementable) model. As an illustration, we present a translation from the IF02 model into the CQ one. The result is a new coherent and formal approach which is useful in overcoming some of the difficulties in the specification and design of object-oriented applications. * Thix wok. xuppod by the PRC-BD3 and WI Extawl Euntpean Rorslmh hjxol in coR&0doo with Digital Bquipnau, amnoa wilbin Ih uq4 of a larger pmjsct whas aim is to realize m aided system for l dvumcd rppliutioo modeling and dcsip. Permission to copy without fee all or part of this material is granted provided that the copies are not made or distributed far direct commercial advantage. the VLDB copyright notice and fhe title of the publication and its date appear, and notice is given that copying is by permission of the Very Large Data Base Endowment.'To copy otherwise, or to republish, requires a fee an&or special permission from the Endowment. Modeling needs for new applications and flaws in the relational model have led to the definition of more powerful mod& which are extended relational [I] or object-oriented [5], [6] and [15]. The generic term for associated systems, of which certain prototypes are described in [26], is Advanced Database Management Systems. As a consequence, current research work is focusing on the definition of new modcling and design approaches able to satisfy the needs of both traditional and advanced applications [7], [l l] and 1131. The prcscntcd research work fits into this context: a new approach whose three main aspects are the following ones. Firstly, a formal object model IF02 1281 is defined for advanced database modeling as an extension of the semantic model IF0 proposed by S. Abiteboul …

Modelled Object Pose Estimation and Tracking by Monocular Vision.

Abstract: This paper presents a new method that permits to solve the problem of determination of a modelled 3D-object spatial attitude from a single perspective image and to compute the covariance matrix associated to the attitude parameters. Its principle is based on the interpretation of at least three segments as the perspective projection of linear ridges of the object model and on the iterative search ( using Kalman filtering) of the model attitude consistent with these projections. The knowledge of the attitude and of the associated covariances enables to use a higher level Kalman filter to track an object along an image sequence. In the tracking process this Kalman filter is used to predict the attitude of the object and the error matrices are used to make robust automatic matches between the image segments and the model ridges. Tracking experiments have been made that proves the validity of this approach. This work has been partially supported by a contract with the European Spatial Agency (ESA) in which society Sagem is the prime contractor.

Temporal Extensions to a Uniform Behavioral Object Model

Abstract: We define temporal extensions to a uniform, behavioral and functional object model by providing an extensible set of structural and behavioral abstractions to model various notions of time for different applications. We discuss the temporal semantics of inheritance by defining a lifespan behavior on objects in a collection. Finally, we give an elaborative example and show that temporal objects can be queried without adding any extra construct to the underlying query language.

Modelling the world with objects

Abstract: The Object Oriented Paradigm and its Origins. Object Oriented Development an Economically Useful Style of Development. An Object Oriented Notation. Systems Analysis and the Object Oriented Paradigm Modelling Systems. Approaches to the Development of Object Oriented Solutions. The Syntheses Approach, the Tools and the Models. The Direct Approach to Objects. Modelling Human Activity Systems with the Object Notation. Modelling Knowledge Based Systems with the Object Notation. Object Oriented Implementation Units. Object Oriented Programming Languages. Rapid Prototyping of Objects. Human Factors and an Object Oriented Approach. Object Oriented Databases. Documentation of Objects. Case Tools for Effective Development. Conclusions.

Statically typed friendly functions via partially abstract types

Abstract: A well-known shortcoming of the object model of Simula and Smalltalk is the inability to deal cleanly with methods that require access to the internal state of more than one object at a time. Recent language designs have therefore extended the basic object model with notions such as friends' methods and protected features, which allow external access to the internal state of objects but limit the scope in which such access can be used. We show that a variant of this idea can be added to any type-theoretic model of the basic object-oriented mechanisms (encapsulation, message passing and inheritance), using a construction based on Cardelli and Wegner's partially abstract types, a refinement of Mitchell and Plotkin's type-theoretic treatment of absract types, a refinement of Mitchell and Plotkin's type-theoretic treatment of abstract types.

Shadows-a flexible support system for objects in distributed systems

Abstract: Shadows is a simple, but flexible, architecture based upon only three hey facilities: object servers, object migration and location-transparent operation invocation. We show how several powerful object properties such as object caching, object shareability, and persistence can easily be created by exploiting only these three concepts. The Shadows architecture requires only capabilities found in common object-oriented languages and modern operating systems. An instance of the Shadows architecture has been implemented in C++ on a distributed memory multiprocessor system. >