[37] | 1 | function J=rgb2xyz(I,ws) |
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| 2 | % RGB2XYZ Color space conversion |
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| 3 | % J=RGB2XYZ(I) converts the RGB image I into CIE XYZ format. The |
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| 4 | % RGB image I can be either of class 'uint8', 'uint16' or |
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| 5 | % 'double'. The output image is always of class 'double' |
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| 6 | % |
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| 7 | % RGB2XYZ(I,WS) uses the specified RGB working space WS. The |
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| 8 | % function supports the following RGB working spaces: |
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| 9 | % |
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| 10 | % * `CIE' E illuminant, gamma=2.2 |
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| 11 | % * `Adobe' D65 illuminant, gamma=2.2 |
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| 12 | % |
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| 13 | % The default workspace is CIE. |
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| 14 | % |
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| 15 | % See also XYZ2RGB(), RGB2DOUBLE(). |
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| 16 | |
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| 17 | % AUTORIGHTS |
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| 18 | % Copyright (C) 2006 Andrea Vedaldi |
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| 19 | % |
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| 20 | % This file is part of VLUtil. |
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| 21 | % |
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| 22 | % VLUtil is free software; you can redistribute it and/or modify |
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| 23 | % it under the terms of the GNU General Public License as published by |
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| 24 | % the Free Software Foundation; either version 2, or (at your option) |
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| 25 | % any later version. |
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| 26 | % |
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| 27 | % This program is distributed in the hope that it will be useful, |
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| 28 | % but WITHOUT ANY WARRANTY; without even the implied warranty of |
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| 29 | % MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
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| 30 | % GNU General Public License for more details. |
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| 31 | % |
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| 32 | % You should have received a copy of the GNU General Public License |
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| 33 | % along with this program; if not, write to the Free Software Foundation, |
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| 34 | % Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. |
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| 35 | |
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| 36 | [M,N,K] = size(I) ; |
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| 37 | |
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| 38 | if K~=3 |
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| 39 | error('I must be a MxNx3 array.') ; |
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| 40 | end |
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| 41 | |
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| 42 | I=rgb2double(I) ; |
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| 43 | |
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| 44 | if(nargin < 2) |
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| 45 | workspace = 'CIE' ; |
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| 46 | else |
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| 47 | workspace = ws ; |
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| 48 | end |
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| 49 | |
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| 50 | switch workspace |
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| 51 | case 'CIE' |
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| 52 | % CIE: E illuminant and 2.2 gamma |
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| 53 | A = [ |
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| 54 | 0.488718 0.176204 0.000000 |
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| 55 | 0.310680 0.812985 0.0102048 |
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| 56 | 0.200602 0.0108109 0.989795 ]' ; |
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| 57 | gamma = 2.2 ; |
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| 58 | |
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| 59 | case 'Adobe' |
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| 60 | % Adobe 1998: D65 illuminant and 2.2 gamma |
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| 61 | A = [ |
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| 62 | 0.576700 0.297361 0.0270328 |
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| 63 | 0.185556 0.627355 0.0706879 |
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| 64 | 0.188212 0.0752847 0.99124 ]' ; |
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| 65 | gamma = 2.2 ; |
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| 66 | end |
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| 67 | |
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| 68 | [M,N,K] = size(I) ; |
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| 69 | |
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| 70 | I = reshape(I.^gamma, M*N, K) ; |
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| 71 | J = A*I' ; |
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| 72 | J = reshape(J', M, N, K) ; |
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| 73 | |
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| 74 | |
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