Patents by Inventor Donald P. Mitchell

Donald P. Mitchell has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Patent number: 7085412
    Abstract: Image data processing and image rendering methods and systems whereby images are displayed on display devices having pixels with separately controllable pixel sub-components. Image data, such as data encoded in a three-channel signal, is passed through a low-pass filter to remove frequencies higher than a selected cutoff frequency, which obtain samples from the color components of the signal that map spatially different image regions to individual pixel sub-components. It has been found that color aliasing effects can be significantly reduces at a cutoff frequency somewhat higher than the Nyquist frequency, while enhancing the spatial resolution of the image. The image data is then passed through sampling filters, A generalized set of filters includes nine filters, one for each combination of one color and one pixel sub-component.
    Type: Grant
    Filed: June 24, 2005
    Date of Patent: August 1, 2006
    Assignee: Microsoft Corporation
    Inventors: John C. Platt, Donald P. Mitchell, J. Turner Whitted, James F. Blinn
  • Patent number: 6973210
    Abstract: Image data processing and image rendering methods and systems whereby images are displayed on display devices having pixels with separately controllable pixel sub-components. Image data, such as data encoded in a three-channel signal, is passed through a low-pass filter to remove frequencies higher than a selected cutoff frequency, which obtain samples from the color components of the signal that map spatially different image regions to individual pixel sub-components. It has been found that color aliasing effects can be significantly reduces at a cutoff frequency somewhat higher than the Nyquist frequency, while enhancing the spatial resolution of the image. The image data is then pass through sampling filters, A generalized set of filters includes nine filters, one for each combination of one color and one pixel sub-component.
    Type: Grant
    Filed: January 12, 2000
    Date of Patent: December 6, 2005
    Assignee: Microsoft Corporation
    Inventors: John C. Platt, Donald P. Mitchell, J. Turner Whitted, James F. Blinn
  • Patent number: 6393145
    Abstract: Techniques for improving the resolution of images (either analog images, analytic images, or images having a higher resolution than that of a display device) to be rendered on patterned displays. In one aspect of the present invention, an overscaling or oversampling process may accept analytic character information, such as contours for example, and a scale factor or grid and overscale or oversample the analytic character information to produce an overscaled or oversampled image. The overscaled or oversampled image generated has a higher resolution than the display upon which the character is to be rendered. Displaced samples of the overscaled or oversampled image are then combined (or filtered). An analytic image, such as a line drawing for example, may be applied to the oversampling/overscaling process as was the case with the character analytic image. However, since the analytic image may have different units than that of the character analytic image, the scale factor applied may be different.
    Type: Grant
    Filed: July 30, 1999
    Date of Patent: May 21, 2002
    Assignee: Microsoft Corporation
    Inventors: Claude Betrisey, Bodin Dresevic, Donald P. Mitchell, John C. Platt
  • Patent number: 6349301
    Abstract: A virtual world environment (VWE) employing a client-server architecture to organize data defining the VWE and objects contained therein in a system of distributed databases. An object in the VWE is one of four basic types including: an artifact, an avatar, a portal, and a room. A world database is maintained by a server computer and is the central storehouse for data defining the entire VWE. Each user has a client computer that is coupled in communication with the server computer. The client computer administers a local database defining at least a portion of the VWE. Each object that is affected by a change in another object is said to be in a bystander region of the other object. The local database maintained by the user's client computer is only updated by the server computer to include changes to the objects associated with the client computer (user) in the bystander region of the other object, i.e., changes evident to an object associated with the user.
    Type: Grant
    Filed: February 24, 1998
    Date of Patent: February 19, 2002
    Assignee: Microsoft Corporation
    Inventors: Donald P. Mitchell, Steven M. Drucker, Kirk J. Marple
  • Publication number: 20010048764
    Abstract: Techniques for improving the resolution of images (either analog images, analytic images, or images having a higher resolution than that of a display device) to be rendered on patterned displays. In one aspect of the present invention, an overscaling or oversampling process may accept analytic character information, such as contours for example, and a scale factor or grid and overscale or oversample the analytic character information to produce an overscaled or oversampled image. The overscaled or oversampled image generated has a higher resolution than the display upon which the character is to be rendered. Displaced samples of the overscaled or oversampled image are then combined (or filtered). An analytic image, such as a line drawing for example, may be applied to the oversampling/overscaling process as was the case with the character analytic image. However, since the analytic image may have different units than that of the character analytic image, the scale factor applied may be different.
    Type: Application
    Filed: July 30, 1999
    Publication date: December 6, 2001
    Inventors: CLAUDE BETRISEY, BODIN DRESEVIC, DONALD P. MITCHELL, JOHN C. PLATT
  • Patent number: 6049341
    Abstract: A collision of a moving object with another object in a 3D virtual world is efficiently determined in real time so that the technique is usable over a network. An object in the 3D virtual world is projected onto a 2D plane. The projection of the object is bounded by a two-sided edge cycle that is formed from a sequence of line segments having endpoints that are consecutively joined at an ordered series of vertices. One side, which is formed by a counterclockwise ordering of the line segments and their respective vertices, is characterized as "front facing." The other side is characterized as "back facing." Additionally, the front and back facing characterization of a side of the edge cycle is determined by the disposition of the moving object, i.e., the closest side of the edge cycle to the moving object is its back facing side. A path line segment is developed for the projection of a path of a moving object onto the 2D plane, and a path line equation is determined for the path line segment.
    Type: Grant
    Filed: October 20, 1997
    Date of Patent: April 11, 2000
    Assignee: Microsoft Corporation
    Inventors: Donald P. Mitchell, Michael D. Marr
  • Patent number: 6028606
    Abstract: A physical camera is modeled to render an image in a computer graphics system. When given the manufacturer's specifications of the physical camera's lenses, including the dimensions and indices of refraction of its lenses, stops, and shutter characteristics, the location of the film surface relative to the lens system, and the orientation of the camera within the scene, the invention accurately and efficiently mimics the physical principles of image formation creating an image which approximates an image produced by the physical camera. The procedure comprises four main elements: (1) the geometric relationships between the lens system, object, and film plane are modeled by precise placement and movement of lens elements, (2) image geometry is computed by using principles of geometric optics, (3) an exit pupil is calculated in order to define a region for efficiently sampling rays, (4) the image irradiance, or exposure at a pixel, is computed according to radiometric principles.
    Type: Grant
    Filed: August 1, 1997
    Date of Patent: February 22, 2000
    Assignee: The Board of Trustees of the Leland Stanford Junior University
    Inventors: Craig E. Kolb, Patrick M. Hanrahan, Donald P. Mitchell
  • Patent number: 5736987
    Abstract: Geometric data for a three-dimensional surface are compressed in regard to the data representing the continuity between triangles in a mesh that represents the three-dimensional surface. The geometric data include information defining the vertices of the triangles comprising the mesh, an indication of the triangle faces, and corner normals to each of the vertices shared by triangles having a common vertex, which indicates the continuity or discontinuity between adjacent triangles of the surface. Vertex rotation continuity (VRC) data are determined for each vertex shared by adjacent triangles, indicating whether the transition between the adjacent triangles is continuous or discontinuous. Further, a dihedral angle between each pair of adjacent triangles is determined and associated with the VRC bit. The VRC data are sorted by the associated dihedral angles, enabling an optimal dihedral angle to be selected.
    Type: Grant
    Filed: March 19, 1996
    Date of Patent: April 7, 1998
    Assignee: Microsoft Corporation
    Inventors: Steven M. Drucker, Donald P. Mitchell