Image processing for crack detection and length estimation

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BB BSB
BB BSB am 9 Apr. 2015
Beantwortet: Preetham Manjunatha am 30 Nov. 2024 um 6:42
Hi, I have written the following matlab code to do the following:-
  • load rgb image of surface
  • contrast stretch
  • convert rgb to gray scale
  • image segmentation
  • morphological operations (thin, clean , fill, etc...)
  • imtool for pixel length determination
  • Calculation of crack length based on calibration of image and above determined pixel lenght.
My aim is to develop the SIMPLEST matlab code for automatic detection of cracks and estimate the length of the crack (if possible other geometrical properties) from a sample image.
The code is shown below:
%%load image
I=imread('two.jpg');
figure,imshow(I)
title('Original image')
%%Image adjust
Istrech = imadjust(I,stretchlim(I));
figure,imshow(Istrech)
title('Contrast stretched image')
%%Convert RGB image to gray
Igray_s = rgb2gray(Istrech);
figure,imshow(Igray_s,[])
title('RGB to gray (contrast stretched) ')
%%Image segmentation by thresholding
%use incremental value to run this selection till required threshold 'level' is
%achieved
level = 0.08;
Ithres = im2bw(Igray_h,level);
figure,imshow(Ithres)
title('Segmented cracks')
%%Image morphological operation
BW = bwmorph(gradmag,'clean',10);
figure,imshow(BW)
title('Cleaned image')
BW = bwmorph(gradmag,'thin', inf);
figure,imshow(BW)
title('Thinned image')
BW = imfill(gradmag, 'holes')
figure,imshow(BW)
title('Filled image')
%%Image tool
figure,imtool(BW1)
figure,imtool(I)
%%Calaculate crack length
calibration_length=0.001;
calibration_pixels=1000;
crack_pixel=35;
crack_length=(crack_pixel *calibration_length)/calibration_pixels;
Please, I need help from image specialist to improve the code from above to meet my aim. I have also attached a sample picture that I am using for this code.
Picture two.jpg is attached below:
Thanks
  3 Kommentare
Hari krishna
Hari krishna am 3 Nov. 2019
Could someone please help me to measure the crack and sketch a line on a diagram .

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Akzeptierte Antwort

Image Analyst
Image Analyst am 9 Apr. 2015
You're just arbitrarily setting
crack_pixel=35;
You're not even doing it manually (with user assistance) - you're just setting some arbitrary number. What's up with that? If you need code to find the distance between the farthest points in a binary blob, see my attached demo.
  15 Kommentare
Pilli Lalvinnu
Pilli Lalvinnu am 7 Mai 2022
ma'am I am doing the same project. I would reaaly appreciate it if you could help me out!
Image Analyst
Image Analyst am 7 Mai 2022
@Pilli Lalvinnu, sure. What sort of help do you need? I'm assuming you started with the solutions given here but they didn't work for your image(s) so start a new question with your code and images attached, and ask a specific question and we'll help.

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Weitere Antworten (6)

Dan
Dan am 13 Apr. 2015
I just glanced at your code and if you need a completely automated system, you need to either define what constitutes a crack beforehand OR have the system learn these rules using something like a neural net.
But... that's a bigger project. In the short term, you might want to play with the graythresh function that will automate your selection of a threshold.
Just my $0.02.
Dan
  1 Kommentar
BB BSB
BB BSB am 14 Apr. 2015
Bearbeitet: BB BSB am 14 Apr. 2015
I see, for timeline limits Id rather attempt the easier of the 3 methods you outlined which I guess is playing around with graythresh function.
Any hints as to how or what to look out for in doing so? Because my first approach would be to scale by a factor??? make any sense? Thanks.

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Yashwanth G M
Yashwanth G M am 25 Mär. 2019
Sir help me to find out the area of a solar panel interms of Sq.mm....

Ram kumar R
Ram kumar R am 12 Feb. 2020
i got error in line no.21 as Ithres = im2bw(Igray_h,level) can u explain it ?
  4 Kommentare
Ayoub MOSSLIH
Ayoub MOSSLIH am 28 Feb. 2021
Undefined function or variable 'gradmag'.
Error in Untitled (line 30)
BW = bwmorph(gradmag,'clean',10);
Image Analyst
Image Analyst am 28 Feb. 2021
@Ayoub MOSSLIH, we have no idea what code you ran. Please start a new question and attach your image and m-file there.

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Image Analyst
Image Analyst am 2 Jan. 2021
See my attached demo that computes both the tortuosity and mean width.
  10 Kommentare
AMAR SAISH
AMAR SAISH am 2 Jan. 2023
sir, i have done image segmentation for crack images. Now, i want to find the length and width of crack, so i should use this code on original images or segmented images ??

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Meherunnisa
Meherunnisa am 12 Mai 2023
%%load image
I=imread('two.jpg'); figure,imshow(I) title('Original image')
%%Image adjust
Istrech = imadjust(I,stretchlim(I)); figure,imshow(Istrech) title('Contrast stretched image')
%%Convert RGB image to gray
Igray_s = rgb2gray(Istrech); figure,imshow(Igray_s,[]) title('RGB to gray (contrast stretched) ')
%%Image segmentation by thresholding %use incremental value to run this selection till required threshold 'level' is %achieved
level = 0.08; Ithres = im2bw(Igray_h,level); figure,imshow(Ithres) title('Segmented cracks')
%%Image morphological operation
BW = bwmorph(gradmag,'clean',10); figure,imshow(BW) title('Cleaned image')
BW = bwmorph(gradmag,'thin', inf); figure,imshow(BW) title('Thinned image')
BW = imfill(gradmag, 'holes') figure,imshow(BW) title('Filled image')
%%Image tool
figure,imtool(BW1) figure,imtool(I)
%%Calaculate crack length
calibration_length=0.001; calibration_pixels=1000; crack_pixel=35;
crack_length=(crack_pixel *calibration_length)/calibration_pixels;
  1 Kommentar
Image Analyst
Image Analyst am 12 Mai 2023
Your crack length computation does not even look at any measurements from the image. It just uses arbitrary values hard coded in.

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Preetham Manjunatha
Preetham Manjunatha am 30 Nov. 2024 um 6:42
Here is the MATLAB code to calculate/estimate the crack area, width and length. In addition, this package assumes the crack is segmented either using morphological method ormultiscale gradient-based or deep learning semantic segmentation methods. This package estimates the crack area, width and length (pixel scale can be provided to estimate these physical quantities).

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