I have an image of canal. I just want the edge of the canal to be display for detecting cracks in it. How do i get only edge portion of canal?

How do I get only edge portion of the canal image so I can detect a crack in it?

Answer 1

[Image Analyst]

Did you try edge() or imgradient()?

[Jainee Solanki]

I dont know how to use it Can u share the code plz?

[Image Analyst]

You mean like

edgeImage = imgradient(grayScaleImage);

Did you read the help for either of the two functions and look at the examples?

[Jainee Solanki]

n=imread('Canal_Images\a7.jpeg'); imshow(n); title('original');

img=rgb2gray(n); imshow(img);

b=edge(img,'canny');

imshow(b); title('canny');

After this, I need to cut the remaining portion other than the edge of the canal. So I need to cut the image to focus only on edge.How can I do it now?

[Jainee Solanki]

Yes i read it.Please help me out

[Image Analyst]

Use the Color Thresholder (on the Apps tab of the tool ribbon) to mask out only bight stuff - the walls of the canal.

[Jainee Solanki]

Can you show the screenshot of it(Color Threshold)? With code please

[Image Analyst]

Click the Export button on the App to get the code:

function [BW,maskedRGBImage] = createMask(RGB)
%createMask  Threshold RGB image using auto-generated code from colorThresholder app.
%  [BW,MASKEDRGBIMAGE] = createMask(RGB) thresholds image RGB using
%  auto-generated code from the colorThresholder app. The colorspace and
%  range for each channel of the colorspace were set within the app. The
%  segmentation mask is returned in BW, and a composite of the mask and
%  original RGB images is returned in maskedRGBImage.

% Auto-generated by colorThresholder app on 26-Nov-2017
%------------------------------------------------------

% Convert RGB image to chosen color space
I = rgb2hsv(RGB);

% Define thresholds for channel 1 based on histogram settings
channel1Min = 0.018;
channel1Max = 0.168;

% Define thresholds for channel 2 based on histogram settings
channel2Min = 0.103;
channel2Max = 1.000;

% Define thresholds for channel 3 based on histogram settings
channel3Min = 0.641;
channel3Max = 1.000;

% Create mask based on chosen histogram thresholds
sliderBW = (I(:,:,1) >= channel1Min ) & (I(:,:,1) <= channel1Max) & ...
  (I(:,:,2) >= channel2Min ) & (I(:,:,2) <= channel2Max) & ...
  (I(:,:,3) >= channel3Min ) & (I(:,:,3) <= channel3Max);
BW = sliderBW;

% Initialize output masked image based on input image.
maskedRGBImage = RGB;

% Set background pixels where BW is false to zero.
maskedRGBImage(repmat(~BW,[1 1 3])) = 0;

end