Detecting particular Line(EDGE) in the total image

I tried a lot to detect the line(EDGE) which is in red portion in the linked image http://tinypic.com/r/2qntaip/7

But was able to get the small line segments not the full line as in image.. Can anyone help me finding out the full line

Answer 1

[Image Analyst]

Well you're in luck because two other people are working on the very same project. They are

Joseph: http://www.mathworks.com/matlabcentral/answers/18447-extracting-frequency-components-of-line-in-a-image

and Naga Ponduru: http://www.mathworks.com/matlabcentral/answers/18685-how-to-find-spatial-wave-length-or-spatial-frequency-for-this-image

Hopefully those two can help you. With three of you on it now, it shouldn't be too hard.

[Gova ReDDy]

After peforming some operations I was able to get this image

http://tinypic.com/view.php?pic=dwfjop&s=7

After that I worked out to remove the unwanted lines using ''imerode'' but as my required line itself consisting of line segments I was unable to go further...

Can anyone suggests how to detect this line as shown in the image

http://tinypic.com/view.php?pic=ad1zn&s=7

[Image Analyst]

Did you contact Joseph and Naga Ponduru?

[Gova ReDDy]

Thanks for your valuable suggestion ..And we need to do it in different methods....

[Image Analyst]

Why? Why is that a need??? Aren't you all working on the same project in your company and you just need to get it solved no matter how? Or is this a classroom assignment that you're not allowed to collaborate on? Or, are you actually all three people?

Answer 2

[Artik Crazy]

Try hough transform as in this example:

http://www.mathworks.com/help/toolbox/images/ref/hough.html

[Gova ReDDy]

I think Hough transform detects the lines And the line I wanted to display is at an angle of -45 degrees.So I want to display this particular line only(making the other parts invisible) in the image.

Answer 3

[Gova ReDDy]

I used filtering with kernel of -45 degree lines and result image is

<http://tinypic.com/view.php?pic=ad1zn&s=7>

After this I worked out with imerode with strel('line',10,-45) which resulted in the discontinuties in the required line like this

http://tinypic.com/r/59sx9u/7

Can someone pls guide me something about how to get the full required line

[Walter Roberson]

imerode is used to _remove_ information. Unless you flip black and white and then use imerode to erode what is currently the black, you are not going to be extending connecting the white parts, just throwing them away.