Is there a way to threshold the background out of the image, to leave only the object?

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Teshan Rezel 2021-8-3

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评论： Tanjena Azim 2021-8-5

Hi folks,

I have images that look like the following, and I'm trying to threshold out the background. For some images, this is a very straightforward endeavour. For others, however, it's not that easy because the background and object have similar greyscale levels.

Ultimately, I want to use regionprops() to measure the object's properties.

May I please ask if there's a way to get around this?

My images look like this:

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kanika bhalla 2021-8-4

Have you tried thresholding method like graythreshold

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采纳的回答

Image Analyst 2021-8-4

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编辑：Image Analyst 2021-8-4

在 MATLAB Online 中打开

Try imbinarize(). Then check the mean gray level in the center of the mask image and compare it to the mean gray level at the top of the image. If the mask is dark in the center and bright around the top, then invert the mask. Something like (untested)

mask = imbinarize(grayImage);
[rows, columns] = size(mask);
row = round([rows/2-50 : rows/2+50]);
col = round([columns/2-50 : columns/2+50]);
if mean2(mask(1:10)) > mean2(mask(row, col))
    % Mask at top is white and in middle is black.  Need to invert it.
    mask = ~mask;
end

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Image Analyst 2021-8-5

@Tanjena Azim Like I already said, I don't know what NROI is. Plus I'm not a watermark expert. I've only played around with it a little bit - probably less than you.

And I don't think the original poster, @Teshan Rezel, knows or cares about watermarks. It's totally unrelated to this discussion thread.

Tanjena Azim 2021-8-5

@Image Analyst Thank you, sir

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