File:Barns grand tetons YCbCr separation.jpg
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本预览的尺寸：200 × 598像素。 其他分辨率：80 × 240像素 | 160 × 480像素 | 257 × 768像素 | 342 × 1,024像素 | 1,600 × 4,780像素。
原始文件 （1,600 × 4,780像素，文件大小：825 KB，MIME类型：image/jpeg）
摘要
| 描述 |
English: This takes the image Barns grand tetons.jpg and displays the Y, Cb and Cr elements of it.
Note that the Y image is essentially 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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| 日期 | 2006年12月26日 (上传日期) | ||
| 来源 | Based on the (public domain) photo Image:Barns grand tetons.jpg. Code above and resulting output by Mike1024. | ||
| 作者 | Mike1024 | ||
| 授权 (二次使用本文件) |
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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 available. 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');
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| 日期/时间 | 缩略图 | 大小 | 用户 | 备注 | |
|---|---|---|---|---|---|
| 当前 | 2006年12月26日 (二) 11:58 | | 1,600 × 4,780（825 KB） | wikimediacommons>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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