# matrix manipulation for color spaces.

조회 수: 2 (최근 30일)
Malini Bakthavatchalam 2020년 5월 19일
답변: vecdi 2024년 6월 11일
Hi , I have an image . I want to convert that to [3 3] matrix value to play with color space. I understand imead will convert image to matrix form but if I want 3 3 matrix, How should I proceed?
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darova 2020년 5월 19일
Can you explain more? What size of your image? And what kind of conversion you want?
Malini Bakthavatchalam 2020년 5월 19일
tVersion: ''
Width: 480
Height: 502
BitDepth: 24
ColorType: 'truecolor'
FormatSignature: ''
NumberOfSamples: 3
This is my image size. The image is just a face of a girl. So I want to convert this image in DKL space and work on illusion project.

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### 채택된 답변

Walter Roberson 2020년 5월 19일
편집: Walter Roberson 2020년 5월 19일
You probably do not want a 3 x 3 images. What you probably want is to let T be a 3 x 3 transformation matrix, and RGB be your RGB image, then
M = reshape(RGB, [], 3);
transformed = M * T;
nonRGB = reshape(transformed, size(RGB));
##### 댓글 수: 26이전 댓글 24개 표시이전 댓글 24개 숨기기
Malini Bakthavatchalam 2020년 5월 25일
Yes, thank you I got your point, so I wrote my final code for converting into DKL color space back into RGB..
clear all
close all
clc
MyImrgb = reshape(im2double(RGB), [],3);
Imrgb = MyImrgb.^2.2; %gamma correction
[x, y, z] = size(Imrgb);
ldrgyv2rgbMat = [1,1,0.236748566577269;
1,-0.299338211934457,-0.235643322285071;
1,0.0137437185685517,1]; % B (mat based on the classic calibration technic)
MyImrgbCol = reshape(Imrgb, [x*y, z]);
MyImldrgyvCol = ldrgyv2rgbMat\(MyImrgbCol'*2 - 1);
figure(1), imshow(RGB)
figure(2), imshow(MyImldrgyvCol)
But i get error
Error using \
Matrix dimensions must agree.
Error in dkltry2 (line 12)
MyImldrgyvCol = ldrgyv2rgbMat\(MyImrgbCol'*2 - 1);
Malini Bakthavatchalam 2020년 5월 25일
Also, I have one more doubt, I used an color thresholder to remove my background. and I used that image in the color space transformation. but now when I use my complete code for the project, it is still calculating my histogram with background so how can i solve the issue.. I am attaching my complete code here

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### 추가 답변 (1개)

vecdi 2024년 6월 11일
MyImrgb = reshape(im2double(RGB), [],3);
Imrgb = MyImrgb.^2.2; %gamma correction
[x, y, z] = size(Imrgb);
ldrgyv2rgbMat = [1,1,0.236748566577269;
1,-0.299338211934457,-0.235643322285071;
1,0.0137437185685517,1]; % B (mat based on the classic calibration technic)
MyImrgbCol = reshape(Imrgb, [x*y, z]);
MyImldrgyvCol = ldrgyv2rgbMat\(MyImrgbCol'*2 - 1);
figure(1), imshow(RGB)
figure(2), imshow(MyImldrgyvCol)
But i get error
Error using \
Matrix dimensions must agree.
Error in dkltry2 (line 12)
MyImldrgyvCol = ldrgyv2rgbMat\(MyImrgbCol'*2 - 1);

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