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area of many cracks in image

Asked by Nida Aleqabie on 14 Jul 2019
Latest activity Answered by Nida Aleqabie on 16 Jul 2019
hello
i am ask about how can find the objects in image
type of image: street image that contine crack
i need to find the crack and compute the area of each crack in image and then get Priority to the crack have big area

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3 Answers

Answer by Image Analyst
on 14 Jul 2019
 Accepted Answer

What I'd do is:
  1. Take a photo of a completely uniform white sheet to get a background that you can use for lens shading correction. That's why when you thresholded you had stuff from the corners and edges.
  2. Turn that image into an image where each pixel is the percentage of light that hits that pixel.
  3. Snap an image of perfect concrete and divide that image by the percentage image to create an image like you would have had, had you had an imaging system with no shading at all.
  4. Use stdfilt() to see what the normal variation is in that kind of image.
  5. Snap and background correct an image with a crack in it.
  6. Use stdfilt() on it then threshold it at a value higher than normal, because cracks and edges will have a higher standard deviation than uniform, perfect concrete.
  7. Use regionprops() on the thresholded image to make whatever measurements you want.
Attach your perfect image, your white background sheet image, and your image with a crack in it if you need help. I'm attaching a background correction demo to help you.
See my Image Segmentation Tutorial if you need help with masking, filtering, measuring, regionprops, etc.: in my File Exchange

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Answer by Nida Aleqabie on 15 Jul 2019

thank u very much
can you help me more with asimple example
with my best wishes

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Image Analyst
on 15 Jul 2019
Why don't you attach your uniform white sheet image, and your perfect, no crack image?
that is my perfect image with no crack

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Answer by Nida Aleqabie on 16 Jul 2019

plz sear mage Analyst can you help me

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