US4371872A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Fractional clock edge smoother for a real-time simulation of a polygon face object system
Assignee: Raytheon Co
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Filing: 1979-07-23
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Granted: 1983-02-01
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Expires: 1999-07-23
Abstract
Abstract The data base for an aircraft flight simulator provides position data for each vertex of each object face in the gaming area plus color, intensity, etc. for each face. The vertex data is combined with aircraft position data and processed to generate two dimensional display vectors (Vd=Xd+Yd) for each vertex. A display generator converts the Xd portion for each vertex into a series of scanline-edge intersections Xdc which define the leading and trailing intersections between each horizontal scanline and the edges of each face. The MSB portion of the intersection coordinate Xdc of each scanline-edge intersection is compared to the incrementing pixel number as the scan proceeds to determine which pixel contains the intersection. The actual change within each pixel of intensity or color associated with scanning across the edge is determined by the LSB portion of Xdc. Each pixel is subdivided into a set of fractional pixels having progressively delayed START DISPLAY times. The LSB portion identifies the particular start time for each edge-scanline intersection. This increased resolution in the horizontal position of each change in intensity or color correspondingly reduces the horizontal dimension of the "staircase" effect inherent in digital displays. The spacing between adjacent START DISPLAY times may be adjusted to accommodate the "worst case" requirement of clearance between start pulses. The resulting series of nonuniformly spaced start times may then include more start times within a single pixel, further reducing the staircase effect.
Inventors
- 👤 Walter A. Rossman
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 11:28
CPC Classifications
G; G09; G09B; G09B9/00; G09B9/02; G09B9/08; G09B9/30; G09B9/301; G06; G06T; G06T15/00; G06T15/50; G06T15/503; G09G; G09G5/00; G09G5/20
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
296 words
An image data system responsive to digital image data including position data which defines the position of the vertices of polygon faces forming the image, and corresponding visual data which defines the visual characteristics of each face, for providing digital display data to a scanline-pixel type display device, comprising: image processor means for receiving the image position data and providing the display coordinates for each vertex of each polygon face of the image to be displayed on the display device; means responsive to the display coordinates of each vertex for determining the scanline numbers and pixel numbers within each scanline of the sequence of leading and trailing intersections of the edges of each face with the scanlines, and responsive to the corresponding visual data for providing a video signal to the display device along each scanline between the leading and trailing edge intersections of each face for generating the corresponding visual characteristics for that face on the display device; scanline memory for receiving each scanline number and the pixel numbers of each intersection within that scanline and the corresponding visual data, and for sequentially providing each intersection pixel number and corresponding data by order of scanline and pixel; pixel clock for the scanlines; pixel counter for sequentially incrementing in response to the pixel clock to define the current pixel count as each scanline proceeds; comparator means for comparing the most significant bit portion of the current intersection pixel number with the current pixel count to advance the corresponding visual data out of the scanline memory; fractional pixel means responsive to the least significant bit portion of the current intersection pixel number for providing a series of progressively and non-uniformly delayed display start times within the current pixel for controlling the display of the corresponding visual data.
Claim 2
Dependent Claim
296 words
An image data system responsive to digital image data including position data which defines the position of the vertices of polygon faces forming the image, and corresponding visual data which defines the visual characteristics of each face, for providing digital display data to a scanline-pixel type display device, comprising: image processor means for receiving the image position data and providing the display coordinates for each vertex of each polygon face of the image to be displayed on the display device; means responsive to the display coordinates of each vertex for determining the scanline numbers and pixel numbers within each scanline of the sequence of leading and trailing intersections of the edges of each face with the scanlines, and responsive to the corresponding visual data for providing a video signal to the display device along each scanline between the leading and trailing edge intersections of each face for generating the corresponding visual characteristics for that face on the display device; scanline memory for receiving each scanline number and the pixel numbers of each intersection within that scanline and the corresponding visual data, and for sequentially providing each intersection pixel number and corresponding data by order of scanline and pixel; pixel clock for the scanlines; pixel counter for sequentially incrementing in response to the pixel clock to define the current pixel count as each scanline proceeds; comparator means for comparing the most significant bit portion of the current intersection pixel number with the current pixel count to advance the corresponding visual data out of the scanline memory; fractional pixel means responsive to the least significant bit portion of the current intersection pixel number for providing a series of progressively and non-uniformly delayed display start times within the current pixel for controlling the display of the corresponding visual data.
Claim 3
Dependent Claim
49 words
The image date system of claim 1, wherein said fractional pixel means provided time delay between the last start time of the previous pixel period and the first start time of the current pixel period which is greater than the delay between the other pairs of consecutive start times.
Claim 4
Dependent Claim
36 words
The image data system of claim 1, wherein the series of progressively delayed start times provided by said fractional pixel means includes four separate start times which subdivides each pixel period into four fractional pixel periods.
Claim 5
Dependent Claim
28 words
The image data system of claim 3, wherein said fractional pixel means provides a first fractional pixel period which is shorter than the other three fractional pixel periods.
Claim 6
Dependent Claim
28 words
The image data system of claim 3, wherein said fractional pixel means provides a fourth fractional pixel period which is longer than the other three fractional pixel periods.
Claim 7
Dependent Claim
109 words
An image data system responsive to digital image data including data which defines image position and visual data which defines image face characteristics for providing digital display data to a display device, comprising: image processor means for receiving the image position data and providing the coordinates for the data to be displayed on the display device; display generator means responsive to the data coordinates for determining the scanline numbers and the pixel numbers, and said display generator means including logic circuit means having comparatively differing propogation times for the image position data for providing a delayed start time within a pixel to control the display of the visual data.
Claim 8
Dependent Claim
109 words
An image data system responsive to digital image data including data which defines image position and visual data which defines image face characteristics for providing digital display data to a display device, comprising: image processor means for receiving the image position data and providing the coordinates for the data to be displayed on the display device; display generator means responsive to the data coordinates for determining the scanline numbers and the pixel numbers, and said display generator means including logic circuit means having comparatively differing propogation times for the image position data for providing a delayed start time within a pixel to control the display of the visual data.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1986-01-31 | 1986-08-02 | 1987-02-01 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1990-01-31 | 1990-08-02 | 1991-02-01 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1994-01-31 | 1994-08-02 | 1995-02-01 | $7700.00 | Window Closed / Lapsed |