Pixelworks, Inc.

Zhongde Wang

Tianbing Brian Teng

Dennis Morel

Carmen Tseng

Mike West

Ashok Aravamudhan

A projector determines horizontal and vertical tilt angles. Using the tilt angles and the inherent properties of the projector, keystone correction corner points for the image can be computed. The keystone correction corner points can be used to perform keystone correction on the image.

Keystone correction derived from the parameters of projectors

We describe a weighted absolute difference based deinterlace method and apparatus. The deinterlace method and apparatus uses weighted absolute differences along different directions as means for interpolating pixel data using edge orientation detection. The apparatus includes a memory adapted to store a current and previous fields and predetermined portions of a future field of an input signal. A motion detector is adapted to detect motion between the future and previous fields. An interpolating circuit is adapted to generate a plurality of output pixels using a corresponding plurality of methodologies. And a switch is adapted to select between the plurality of output pixels responsive to the motion detector.

Weighted absolute difference based deinterlace method and apparatus

We describe a keystone correction system and method. A vertical scalar vertically scales an input image and stores the results to a line buffer. A horizontal scalar retrieves the stored results from the line buffer and horizontally scales the stored results using the relatively small number of lines from the line buffer. The system repeats the vertically scaling, storing, and horizontal scaling until it processes all input image lines.

Keystone correction system and method

An output pixel datum is produced from input pixel data by a method wherein the brightness levels of several input pixels closely associated coordinate-wise with the output pixel, are examined to determine whether a relatively less complex graphics-optimized scaling procedure, or a relatively more sophisticated video-optimized scaling procedure, should be carried out. In the second case, directional interpolation is performed with a plurality of directions, e.g., being considered to determine the direction of minimum brightness level gradient. A plurality of intermediate pixels, e.g., four, are produced, which are aligned perpendicularly to the minimum brightness level gradient direction, their brightness levels being determined from relevant input pixels using linear interpolation. The output pixel brightness level is determined from the intermediate pixels through the use of an appropriate filtering technique, e.g., polyphase FIR filtering. An apparatus for performing the method and a system incorporating the apparatus, are described.

Method and apparatus for two-dimensional image scaling

The invention is a method and apparatus for reducing noise in an image. The method and apparatus involves calculating a plurality of directional operators, comparing the directional operators to a predetermined threshold, and applying a filter responsive to the comparing. The method and apparatus computes the directional operators by taking a weighted sum of the absolute differences between a target pixel and its surrounding pixels. The comparison signals to the method or apparatus the existence of a line or edge. If the method or apparatus detects no edge or line, the method applies a smoothing or averaging filter. If the method or apparatus detects an edge or line, the method applies a median filter in the direction with a minimum directional difference.

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Camas, WA, United States of America

Zhongde Wang