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Member
saillesh
Posts: 13
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colour to grey scale and crack detection

how to convert a colour image to grey scale. also i want to know how to detect the cracks in the objects from their images
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muks
Posts: 7,208

Re: colour to grey scale and crack detection

There are 3 planes involved in a color image. Each plane having values 0-255. By extracting any single plane you can convert the image to a grey scale one.

 

Try extracting the luminance plane (in color plane extraction).

 

Use vision assistant initially to get an idea.....

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muks
Posts: 7,208

Re: colour to grey scale and crack detection

 


how to detect the cracks in the objects from their images

 

 

If the crack in really nicely different from the object then applying a proper threshold and removing small particles and going with a particle analysis will be enough.

 

But we need details.If you can post some images then I can suggest you a method

Member
sudeepn
Posts: 10
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Re: colour to grey scale and crack detection

Use the vision assistant to start with ,as it will help you extract the colour planes and (also gives an option to convert your image to a grey image) as well as it will help you learn about other vision utilities which labVIEW offers . You can detect the cracks or edges by setting proper thresholds . Please describe your application in a little detail so that I can help you with a more precise solution.
Active Participant
VBCoder
Posts: 282

Re: colour to grey scale and crack detection

Saillesh,

What muks suggested is a very practical approach. I personally implemented it with object filtering to detect cracks in an online ceramic plates inspection.

Waleed El-Badry MSc.,MCPD, ISTQB Certified Tester
Assistant Lecturer
Mechatronics Department
Faculty of Engineering
Misr University for Science & Technology

Waleed El-Badry CLAD
Member
Jörn
Posts: 167

Re: colour to grey scale and crack detection

[ Edited ]

to convert a color image to gray scale you can average all three planes or you use different weights for the color planes. Typical weights are

 

30% red + 59% green + 11% blue

 

See also http://forums.ni.com/ni/board/message?board.id=170&message.id=422864#M422864

Message Edited by Jörn on 2009-08-12 12.08.2009 11:48 PM
Member
saillesh
Posts: 13
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Re: colour to grey scale and crack detection

i wan to detect the cracks in tracks of train .can i use fft for this . if any other soluion please help me
Member
saillesh
Posts: 13
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Re: colour to grey scale and crack detection

i have to inspect cracks in the train  tracks . is your method of object filtering is suitable for that ?.
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muks
Posts: 7,208
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Re: colour to grey scale and crack detection

Well posting a few sample images will do a lot of help. I mean there is no other way  we can suggest algorithms to use. We can only keep guessing.
Member
saillesh
Posts: 13
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Re: colour to grey scale and crack detection

im posting my pictures here  (with and without cracks),could u help me with the algorithms.i have taken fft for this, is there any option to get the strength of fft to compare the images?