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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