Convert an image pixel coordinate to physical coordinate

Question

AP 2012-10-14

2
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此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/50787-convert-an-image-pixel-coordinate-to-physical-coordinate

Dear All,

I have a 2D array over the range xmin<x<xmax and ymin<y<ymax which contains the color intensity of each point. It looks like a deformed donut. I needed to find the inner and outer boundary of the donut. In order to achieve this goal, I used image processing and found the boundaries by bwboundaries function. Now I have the boundaries. The boundaries are in rows and columns coordinate. I want to convert them back into physical x,y coordinates. How can I do it?

Thanks,

Ahmad

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Answer 1

Image Analyst 2012-10-14

1
链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/50787-convert-an-image-pixel-coordinate-to-physical-coordinate#answer_61950

编辑：Image Analyst 2012-10-14

在 MATLAB Online 中打开

Yes.

% Get the image size.
[rows columns numberOfColorChannels] = size(imageArray);
% Create the spatial calibration factors.
realWorldUnitsPerPixel_x = (xmax - xmin) / columns;
realWorldUnitsPerPixel_y = (ymax - ymin) / rows;
% Now let's say you had some pixel coordinate (column, row):
realWorldX = xmin + realWorldUnitsPerPixel_x * column;
realWorldY = ymin + realWorldUnitsPerPixel_y * row;
% Now realWorldX and realWorldY are in terms of real world units.