EP0590997A2
Expired / Lapsed
EP
⏱️ 0.0 years remaining
Processing image data
Assignee: Canon Inc
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Filing: 1993-09-30
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Granted: —
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Expires: 2013-09-30
Abstract
Abstract 2-dimensional image data is produced from multidimensional image data. Pixels in 2-dimensional areas are coloured in response to calculated lighting characteristics representing the colour of said areas. Pixel colours are stored in a look-up table addressed by combining a colour value selecting representing colour hue and a level value representing another characteristic of the selected colour. Values within a specific colour or ramp initially vary to increase luminance and latterly vary to decrease saturation. Luminance may vary non-linearly to provide gamma correction. Diffuse and specular reflection can be represented in a single level value.
Inventors
- 👤 Adam M. c/o Canon Res. Ctr Europe Ltd Billyard
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-09 11:44
CPC Classifications
G; G06; G06T; G06T15/00; G06T15/50; G06T15/506
Claims Analysis
Total Claims: 16
Claim 1
Independent Claim
78 words
Apparatus for producing 2-dimensional image data from multi-dimensional image data, wherein pixels in 2-dimensional areas are coloured in response to calculated lighting characteristics representing the colour of said areas, and wherein pixel colours are defined by means of a look-up table which can be addressed by combining a colour value selecting a colour hue and a level value representing another characteristic of the colour to be reproduced, characterised in that said other characteristic includes both luminance and saturation.
Claim 2
Dependent Claim
23 words
Apparatus according to claim 1, wherein traversing the range of level values for each colour value initially increases luminance and latterly decreases saturation.
Claim 3
Dependent Claim
25 words
An apparatus according to claim 1 or 2, wherein level values are generated by combining both diffuse and specular lighting characteristics in a single value.
Claim 4
Dependent Claim
33 words
An apparatus according to claim 1, 2 or 3, further comprising means for interpolating address values for individual image pixels from a look-up table address calculated for a starting pixel of a span.
Claim 5
Dependent Claim
20 words
Apparatus according to claim 1, 2, 3 or 4, wherein luminance varies non-linearly with level value to provide gamma correction.
Claim 6
Dependent Claim
46 words
Apparatus according to any preceding claim, including means for calculating the position of objects in space and for calculating lighting characteristics in response to positional and surface data, wherein positional calculations are performed in floating point arithmetic and lighting characteristics are calculated in fixed point arithmetic.
Claim 7
Dependent Claim
44 words
Apparatus according to any preceding claim, including means for calculating lighting characteristics in response to lighting parameters of surfaces and parameters of light sources, and further including means for non-linearly processing lighting parameters to simulate specular highlight characteristics, without reference to a view position.
Claim 8
Dependent Claim
92 words
Apparatus according to any preceding claim, wherein lighting characteristics of surface primitives to be represented are calculated in response to data representing light sources and lighting parameters defining coefficients of specular reflection and diffuse reflection, wherein: not all primitives have significant levels of specular reflection, and said apparatus includes means for processing primitives having significant levels of specular reflection and other polygons in respective groups in accordance with a first process and a second process respectively, such that successive images of a sequence can be generated without re-testing each primitive for specularity.
Claim 9
Independent Claim
77 words
A method for producing 2-dimensional image data from multi-dimension image data, wherein pixels in 2-dimensional areas are coloured in response to calculated lighting characteristics representing the colour of said areas, and wherein pixel colours are stored in a look-up table which can be addressed by combining a colour value selecting a colour hue and a level value representing another characteristic of the colour to be reproduced, characterised in that said other characteristic includes both luminance and saturation.
Claim 10
Dependent Claim
24 words
A method according to claim 9, wherein traversing the range of level values supplied for each colour initially increases luminance and latterly decreases saturation.
Claim 11
Dependent Claim
24 words
A method according to claim 9 or 10, wherein level values are generated by combining both diffuse and specular characteristics into a single value.
Claim 12
Dependent Claim
36 words
A method according to claim 9, 10 or 11, wherein pixel spans are coloured by interpolating look-up table addresses for individual pixels based on a look-up table address calculated for a starting pixel of each span.
Claim 13
Dependent Claim
19 words
A method according to claim 9, 10, 11 or 12, wherein said luminance varies non-linearly to provide gamma correction.
Claim 14
Independent Claim
50 words
A method according to any of claims 9 to 13, including the steps of calculating the position of objects in space and calculating lighting characteristics in response to positional and surface data, wherein positional calculations are performed in floating point arithmetic and lighting characteristics are calculated in fixed point arithmetic.
Claim 15
Independent Claim
48 words
A method according to any of claims 9 to 14, in which lighting characteristics are calculated in response to lighting parameters of surfaces and the parameters of light sources, the method including non-linearly processing a lighting parameter to simulate specular highlight characteristics without reference to a view position.
Claim 16
Dependent Claim
16 words
An image signal or recording generated using a method or apparatus according to any preceding claim.
References Cited (Backward Citations)
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