Abstract: A method and apparatus are disclosed for determining a direction in which a subject's head is facing. The present invention has particular relevance to monitoring driver conditions in automobiles. By monitoring head positions and motions, the system can estimate driver awareness. Signals or alarms can be activated if the driver does not appear to be aware of driving conditions. The present invention provides a rapid, low cost device for determining pose position, which would be useful in automobiles. A large number of images of various subjects in different poses are stored a memory. The poses are then organized according to tree-structured vector quantization to allow comparison with a sample image of an actual driver. The tree structure is traversed to find a leaf node constituting one of the stored images which is closest to the sample image. The pose of the closest image is outputted as the pose of the sample image.

Abstract: An adaptable, variable rate symbol timing recovery system for a digital sal receiver comprises an analog to digital (A-D) signal converter having analog signal input and digital data signal output terminals. A source of selectable, substantially fixed rate, data sampling clock signals is coupled to the A-D signal converter for sampling a signal received at the input at a predetermined, substantially fixed clock rate, depending on data rate and modulation of the received signal. A digital signal processing loop is coupled to the digital data signal output terminal for adjustably producing interdependent signals in synchronism with the data signals at the output terminal which are asynchronous with respect to the fixed rate clock signals. A Controller is provided for selectively configuring the data sampling clock signal source and the digital signal processing loop according to the data rate and modulation characteristics of the received signal.

Abstract: A system is provided for reconstructing the 3-dimensional motions of a hu figure from a monocularly viewed image sequence in which a statistical approach is used coupled with the use of a set of motion capture examples to build a gaussian probability model for short human motion sequences. In a simplified rendering domain, this yields an optimal 3-d estimate of human motion used to create realistic animations given a 2-d temporal sequence. The subject system is also useful to identify which motion modes are difficult to estimate. In one embodiment, a stick figure is overlaid on the input video image to allow manual correction of incorrectly tracked body parts. The utilization of stick figure correction permits manual correction for a more accurate 3-d reconstruction of the motion depicted in the input video sequence. An interactive tracking system processes real video sequences, and achieves good 3-d reconstructions of the human figure motion.

Abstract: Negative examples are used along with positive examples to modify a Markov Model resulting in lower error rates in classification tasks as compared with conventionally trained Markov models. The subject system is used for identifying particular traits or characteristics of sequences to permit identification of, for instance, inappropriate web page material, hand signing gestures, audio program material type, authorship of a text, with the system also being useful in speech recognition, as well as seismic, medical, and industrial monitoring.

Abstract: The present invention relates to a new and useful learning system. A compr-based system permits a user to create and manipulate basic elements within an environment. The system then represents relationships within the environment. The system and user cooperate to provide a learning opportunity for the user. As the user makes or reviews changes of basic elements, he or she can learn how different aspects of an element affect the overall interactions. Two specific embodiments are disclosed. In a first embodiment, the system is used for exploring geometric patterns. The basic elements are tiles which are formed and manipulated through operations of geometric symmetry. The tiles can be combined into different repeating patterns. Multiple tiles can be used within a pattern. Also, new tiles can be created from portions of the pattern. Thus through simple interactions using basic operations and simple parts, complex effects emerge. In a second embodiment, the system is used for exploring a sociodynamic system.

Abstract: A system for generating a virtual reality environment applies principles of urban planning. Participants interact with the system by designating or anging certain objects or characteristics of the environment. The environment includes designation of districts having similar scenic characteristics. Paths define routes through the districts and within the environment. Specific foci or landmarks can be identified at locations within the environment. In addition to creating a conceptual view of the environment, the system generates a set of scenes representing movement of a participant along a defined walkway through the environment. The scenes are generated as composite images of objects in a perspective view. The objects forming a composite in the scene are determined based upon the characteristics of the district to which the scene applies.

Abstract: A master/slave system is used for performing a surgical procedure such as theterization of cardiac or peripheral vasculature. Movements of catheters or similar tools within a patient are remotely controlled by a surgeon, and the surgeon receives haptic or tactile feedback caused by the movement of the tools within the patient. The system employs a master actuator with cylindrical controls and a slave actuator that engages the tools. The master actuator and slave actuator are electrically coupled to electrical interface circuitry by drive signals and sense signals. A fluid system is coupled to the slave actuator by fluid-carrying tubes for the delivery of contrast and other solutions to be injected into the vasculature for improved imaging and also to pressurize the balloon on a balloon catheter.

Abstract: A file reconciliation process in a distributed file system uses a set of rnal or log files to track the history of file modification at each of different sites, or sets of directories, in a computer system. During reconciliation, sequences of version entries associated with each file in each journal are updated and compared to determine whether (1) a conflict exists for any of the files involved in the reconciliation, and (2) if not, which version of the file is the current version. The version entries contain a hash code or digest that to a high probability uniquely identifies the contents of a file. Sequences of hash codes are used to identify the sequence of file versions. Masks and site indicator fields are included in the journal files and used to track which journal files have copies of version entries for the purpose of deleting version entries when they become obsolete.

Abstract: Apparatus is provided to extend the number of active degrees of freedom of haptic interface to provide the user with the feel of a tool which is cantilevered over obstacles or which experiences frictional drag along its shaft. This is accomplished by providing two additional active degrees of freedom while not limiting the rotation or translation of the handle that the user is grasping. The apparatus constrains, through a 4 degree of freedom gimbal, the shaft of the tool handle, whose tip is controlled by another 3 spatial degree of freedom haptic device. The shaft of the tool slides and rotates in a sleeve bearing or collar which is mounted in a 2 degree of freedom gimbal. The gimbal is rigidly connected to a 2 degree of freedom parallel planar manipulator, with both degrees of freedom of the planar manipulator being powered by actuators used to generate the requisite haptic forces.

Abstract: A system for generating a surface representation from binary sampled data cludes means for iteratively smoothing the surface representation, while constraining the surface to conform to details in the surface of the binary data. Means are also provided to convert the surface representation into a form useful for polygon rendering and for volume rendering, with the subject system useable to generate a smooth surfaces for high quality rendering of objects stored as binary-sampled data.

Abstract: A patient simulation includes a patient generator for providing an image of a body of a patient on a display, where at least one portion of the body an be examined in greater detail; at least one communication device for allowing interaction between the patient and a user; and a behavior generator which causes the patient to appear to respond to treatment. The behavior generator includes psychological state data that allows the patient to react to the user's "bedside manner." Further, the simulation operates on a non-stop basis and in real time.

Abstract: A compact convenient hand-held, accelerometer-based computer control device is utilized to control on-screen animated characters presented by a comer-driven display in which the movement, persona, style, and voice of the character is controlled. The control device detects accelerations which are used to provide the on-screen character a particular persona, style or voice quality determined by the user. Character motion is determined by acceleration patterns based upon a learned language. The system requires only a series of easily learned hand movement patterns for corresponding character control.The style or emotional content of the movement is specified directly from gross accelerometer outputs without pattern matching. The outputs can also be used in connection with speech synthesis to provide voice quality attributes to audible information. The system has particular relevance to control of on-screen characters in interactive theater and virtual reality systems.

Abstract: A voxel-based system for rapidly deforming volumetric objects performs simple deformation calculations for each element of the graphical object to be deformed such that when the object is manipulated, the object stretches or contracts through the movement of a selected element, followed by movement of neighboring elements only if a maximum or minimum preset distance is exceeded between the moved element and its neighbor. Thus elements are moved only if they need to be, which eliminates calculating movements of elements not affected by movement of the selected element. This in turn allows fast propagation of the deformation through the volume represented by the object to the deformed, with the motion constraints being similar to the motion provided by a set of linked elements in a chain.

Abstract: A dynamic synchronous collaboration framework utilizes a distributed synchronization point to permit synchronous collaboration of mobile agent objects in a distributed computer system. The framework simplifies agent collaboration for applications which divide a complex problem into multiple tasks and delegate tasks to multiple mobile agents. The collaboration framework also enables mobile agents within an application to perform synchronous collaboration with affiliated agents in the native language of an associated software application. Such collaboration is accomplished by joining collaborating agents to an agent group. Member agents periodically correlate results through a collaborative sharing within the agent group, and may adopt new behaviors based on the results of the collaboration.

Abstract: An object rendering system having a specialized algorithm is provided to convert a material and geometric description of an object to an X-Ray image of that object for use in medical applications and industrial non-destructive testing, thus to permit presentation of an object not the result of X-Ray in an X-Ray format. The system operates by considering that the object is composed of nested geometric solids, each defined by an enclosing surface, with the material property of each nested solid being defined in terms of an X-Ray mass-attenuation coefficient. Means for adjusting the mass attenuation coefficient of each of the enclosing surfaces is provided to permit each solid to be rendered independently.

Abstract: A virtual reality environment creation, modification and delivery system stores information representing the virtual reality environment in a database where portions of it may be created, modified or delivered without affecting other portions. The database may be accessed, for example, over a network such as a wide area network, to allow database records to be individually updated without affecting other records in the database. In this manner, it is not necessary to read and store an entire virtual reality environment file in order to make changes to it. In addition, characteristics of target machines dictate what version the database reads out, thus to provide a version compatible with the target machine.

Abstract: A linked volumetric representation for graphical objects is presented together with techniques for physically-plausible modeling of object cutting, joining and tearing. In one embodiment, each element is may be explicitly linked to its six nearest neighbors by storing pointers to those neighbors in the element's data structure. The link between two elements can be cut when a graphical representation of cutting tool passes between the elements by setting the appropriate neighbor pointers in the two elements to point to NULL instead of to each other. If material limits in the link between two elements are exceeded during simulation of object deformation, the link can be torn apart by setting the appropriate neighbor pointers in the two elements to NULL. When a joining tool is applied to two volumetric objects in close proximity, edge elements in the two objects that have complimentary neighbors set to NULL can be joined by setting these missing neighbors to point to each other.

Abstract: The present invention relates to a system and method for determining collisions between polyhedron objects represented by their features. Collisions are detected by determining the relative positions of closest features between pairs of polyhedra. The present invention is based upon comparisions of a feature from one polygon with a Voronoi region corresponding to a feature of another polyhedron. If a closest point from each feature is within the Voronoi region of the other feature, then the two features are the closest for that pair of objects. If the features are not within the Voronoi regions, then a new feature for one of the objects or polyhedra is selected based upon the position of the features relative to the Voronoi region. When a feature is of an edge type, the edge is clipped against the planes defining the Voronoi region. A new feature is selected based upon the relative positions of the points where the edge is clipped to the corresponding features defining the Voronoi region.

Abstract: A volumetric data representation for graphical objects encodes the distance of data elements to the nearest object surface, with means being provided for estimating the direction and magnitude of surface normals from the tance values. The subject system can be used to accurately reconstruct the normal direction of a slowly varying surface in volume sampled data for high quality Volume Rendering, accurate force reflection in haptic feedback, and accurate force calculation and object penetration estimation in physically-based graphics.