How to get the bright areas separately from an image?

Hi there,

I have a combustion image in gray scale (Sample), with this I would like to extract the bright areas separately (Sample02).

However, the areas are connected with other areas (merge together), I could not extract them out from the whole area after binarizing the image.

PS: the bright areas are resulted from auto-ignition and the corresponding area and intensity go up very fast, so I want to extract them for analysis.

Any possible solution will be highly appreciated, thanks a lot!

Answer 1

[Image Analyst]

Can you divide the later image by an earlier one? The ratio in the regions where the intensity went up faster than the rest of the image will have a ratio bigger than the rest of the image. Then you can threshold and call regionprops().

ratioImage = double(image2) ./ double(image1);
mask = ratioImage > someValue;
props = regionprops(mask, image2, 'Area', 'MeanIntensity')

[Hao Shi]

Dear Analyst,

Thank you so much for your kind suggestion, it works!!

I tried this method before, there were some noises along the flame boundary, where the intensities also change significantly when the flame propagates. Later I used the filter to filter out the noises, and it looks ok. Thanks a lot!

Before filtering:

After filtering: