Patent US6839688B2 successfully refreshed from Google Patents.
Patent EP0637813A2 successfully refreshed from Google Patents.
EP0637813A2
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EP
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Image processing
Assignee: Philips Electronics UK Ltd
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Filing: 1994-08-02
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Granted: —
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Expires: 2014-08-02
Abstract
Abstract Texture mapping or video mapping is performed in such a way as to obtain perspectively correct images, while at the same time not requiring excessive computational overheads. Non-linear functions required to achieve perspectively correct images are stored in the form of look-up tables. Depth extents at the extremes of a locus of interpolation are compared and from this comparison a particular look-up table, or a pair of look-up tables, are selected. When are pair of look-up tables are selected, it is possible to linearly interpolate between the two, in order to obtain a closer approximation to the desired non-linear response.
Inventors
- 👤 David Edward C/O Philips Research Lab. Penna
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-09 16:50
CPC Classifications
G; G06; G06F; G06F3/00; G06F3/14; G06F3/153; G06T; G06T15/00; G06T15/04
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
78 words
An image processing method for rendering a two dimensional image from three dimensional image data, wherein a polygon defined in three dimensional space is projected into two dimensional space and pixel values from a two dimensional image are mapped onto pixels within said projected two dimensional polygon, characterised in that; positions within said two dimensional image are identified along a locus to be interpolated by addressing values from a look-up table to obtain a substantially perspectively correct mapping.
Claim 2
Dependent Claim
25 words
A method according to Claim 1, wherein a plurality of look-up tables are provided and a required look-up table is selected by processing depth values.
Claim 3
Dependent Claim
27 words
A method according to Claim 2, wherein said depth values are processed by dividing a first by a second, in order to produce a table selection value.
Claim 4
Dependent Claim
21 words
A method according to Claim 2, wherein said depth values are processed by calculating the logarithm for each of said values.
Claim 5
Dependent Claim
40 words
A method according to Claim 4, wherein said values are shifted and an indication of the number of shifts made are supplied to look-up table means to produce an indication of the look-up table to be selected for the mapping.
Claim 6
Independent Claim
33 words
A method according to any one of Claims 1 to 5, wherein two look-up tables are selected and new values for performing the look-up operation are determined by a process of linear interpolation.
Claim 7
Dependent Claim
91 words
Image processing apparatus arranged to render a two dimensional image from three dimensional image data, such that a polygon defined in three dimensional space is projected into two dimensional space and pixel values from a two dimensional image are mapped onto pixels within the projected polygon, characterised by: storage means arranged to store look up tables of values defining perspective-correcting functions, and processing means arranged to interpolate a locus of positions within the input image by addressing values from a look up table so as to perspectively correct the interpolated positions.
Claim 8
Dependent Claim
34 words
Apparatus according to claim 7, wherein said storage means is arranged to store a plurality of look up tables and a selector is arranged to select look up tables by processing depth (z) values.
Claim 9
Dependent Claim
27 words
Apparatus according to claim 8, wherein said selector is arranged to divide a first depth value by a second depth value to produce a table selection value.
Claim 10
Dependent Claim
19 words
Apparatus according to claim 8, wherein said selector processes depth values by calculating the logarithm of said depth values.
Claim 11
Dependent Claim
37 words
Apparatus according to claim 10, wherein said selector includes a shift register, means for shifting values in said register and processing means for processing said shifted values, to provide an indication of the required look up table.
Claim 12
Dependent Claim
36 words
Apparatus according to any of claims 7 to 11, wherein said selector is arranged to select two look up tables and said processor is arranged to interpolate values between values read from said look up tables.
References Cited (Backward Citations)
No citation records indexed.
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