How to calculate the area of an input image?

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Elias Unk
Elias Unk 2017-8-14
评论： Image Analyst 2019-8-15
I want to calculate the area of the FULL binary image the user inputs is it as simple as heightXwidth if so what function does it

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Star Strider
Star Strider 2017-8-14
编辑：Star Strider 2017-8-14
If it is a binary image (so a 2D array), the numel (link) function will do what you want.
It is equivalent to prod(size(BI)), where ‘BI’ is your binary image.

更多回答（2 个）

Image Analyst
Image Analyst 2017-8-14
If you want the number of rows and columns of the binary image, you can do this:
[rows, columns] = size(binaryImage);
If you want the number of pixels (sum total, no matter whether black or white), you can do this:
numPixels = row * columns;
or you can use numel():
numPixels = numel(binaryImage);
If you want the area of just the white/1/true pixels, then you can do
foregroundArea = sum(binaryImage(:)); % Result is in pixels.
backgroundArea = numel(binaryImage) - foregroundArea;
Hopefully one of those examples will give you what you want, because we're not 100% sure what you want.
  2 个评论
Warid Islam
Warid Islam 2019-8-15
Hi Image Analyst,
I want to find the area of an RGB image. I was wondering if i need to convert it to grayscale image and then find the area or I can find the area of the RGB image directly? Thank you.
Image Analyst
Image Analyst 2019-8-15
No, you can find the area directly. See my attached spatial calibration demo.

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Jan
Jan 2017-8-14
This sounds like a job for the size() command. But what does "FULL" mean here and how does the user "inputs" the image?
  1 个评论
Elias Unk
Elias Unk 2017-8-14
Yes that partially did it now i need to multiply it's 2 elements how do i get it?

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