File:Barns_grand_tetons_YCbCr_separation.jpg
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Summary
DescriptionBarns grand tetons YCbCr separation.jpg |
English: This takes an image (Image:Barns grand tetons.jpg) and displays the Y, Cb and Cr elements of it.
Note that the Y image is essentailly a greyscale copy of the main image; that the white snow is represented as a middle value in both Cb and Cr; that the brown barn is represented by strong Cb and strong Cr; that the green grass is represented by strong Cb and weak Cr; and that the blue sky is represented by weak Cb and weak Cr. The murkiness of the Cb and Cr elements (to the human eye) demonstrate why many image compression codecs downsample colour; details in Y are much more visible than in Cb or Cr. |
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Date | 26 December 2006 (upload date) | |||
Source | Based on the (public domain) photo Image:Barns grand tetons.jpg. Code above and resulting output by Mike1024. | |||
Author | Mike1024 | |||
Permission (Reusing this file) |
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Generator code
In MATLAB:
RGBimage = imread('barns_grand_tetons.jpg'); [height,width,depth]=size(RGBimage); YCbCrimage=RGB2YCbCr(RGBimage); % If you don't have the right version/toolkit this function % might not be availiable. Luckily, it's easy to implement % ourselves. Drop me (Mike1024) a message and I'll send you % my code to do it. % Newer versions of matlab need outputimage=zeros(height*4,width,depth,'uint8'); outputimage=uint8(zeros(height*4,width,depth)); for w=1:width, for h=1:height, outputimage(h,w,1) = YCbCrimage(h,w,1); %Copy Y, Cb and Cr for normal image outputimage(h,w,2) = YCbCrimage(h,w,2); outputimage(h,w,3) = YCbCrimage(h,w,3); outputimage(h+height,w,1) = YCbCrimage(h,w,1); %Copy Y only for first component outputimage(h+height,w,2) = 128; outputimage(h+height,w,3) = 128; outputimage(h+(2*height),w,2) = YCbCrimage(h,w,2); %Cb only for second component outputimage(h+(2*height),w,1) = 128; outputimage(h+(2*height),w,3) = 128; outputimage(h+(3*height),w,3) = YCbCrimage(h,w,3); %Cr only for third component outputimage(h+(3*height),w,1) = 128; outputimage(h+(3*height),w,2) = 128; end end image(YCbCr2RGB(outputimage)); imwrite(YCbCr2RGB(outputimage),'YCbCr_separation.jpg','jpeg');
Items portrayed in this file
depicts
26 December 2006
image/jpeg
fb1e6384f89b9a5b3e8bebcd3065c2817b00a1b5
844,403 byte
4,780 pixel
1,600 pixel
File history
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Date/Time | Thumbnail | Dimensions | User | Comment | |
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current | 10:58, 26 December 2006 | 1,600 × 4,780 (825 KB) | Wdwd | ==Summary== This takes an image (Image:Barns grand tetons.jpg) and displays the Y, Cb and Cr elements of it. Note that the Y image is essentailly a greyscale copy of the main image; that the white snow is represented as |
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