How can I extract/detect, separate the wall from the window using vertical and horizontal line detection?

How can I extract/detect, separate the wall from the window using vertical and horizontal line detection?

Also, how can I separate the rectangular shape from the wall?

The goal is to separate the wall area from the window and later the rectangular shape area from the wall (if there is a shape) for any window/wall situation. Is it possible if I don't know in advance the dimensions, color, width of the window frame etc., only the shapes (which contain mostly horizontal and vertical lines)?

I hope someone can help me with this.

Thank you in advance!

Answer 1

[Image Analyst]

Try edge() and imfill().

Is it your assignment?

[L]

Hello Image Analyst,

Thank you for the response.

I have tried with edge function earlier with the Sobel detector (this results looks good), but the problem is later. When I use the imfill() function, with 'holes' option I've got the same image like after the edge detection. When I use the 'conn' option with any parameter, i've got an almost pure white image. This was my first intention.

Also, I have tried with simple derivation in x and y directions (to highlight only the edges of the window/wall border), but the derivation result was worse than with the Sobel detector. Now, I am stucked. The only reasonable intermediate result is the image after the edge() function. I can't find a way to connect somehow the border lines around the window/wall.

I tried with morphological gradient too. In this case I saw somehow the main lines

Yes, this is an assignment from my mentor, I was searching the Matlab Answers, but didn't find anything similar. Naturally, I am not expecting to someone else solve this, I would like to get some tips.

Now, I am thinking about erosion to highlight somehow the vertical and horizontal lines. What do you think about that?

I think the morphology should be the easiest way to do this areas separation.

I have attached you some image examples of the same window/wall.

Thank you in advance.

[Image Analyst]

You could try thresholding, then using bwperim().

Or you could try reducing reducing the scale of the image with imresize() because the scale of the Sobel window (3x3) is far too small to find the very large edges you're interested in.

Or you could try a difference of Gaussians filter with proper kernel sizes and proper Gaussian spread.

[L]

Hello,

Thank you for the guiding.

I have tried with imbinarizee() and it gives a good result. Next, I have used the bwperim() with 26 connectivity, but the resut was almost same. Finally, I have applied the opening with disk SE. When in the scene are the wall and the window, it looks good, but the opening cut the part of the wall. When there is a shape in the scene, it is a problem. I have attached nyou the images.

Thank you.

[L]

Hello Image Analyst,

Is it possible to extract the window, or the wall (or the shape) using the bwconncomp(), regionprops() and checking the bounding box?

Thank you.

[L]

Hello,

I have reduced the scale and I've got the 2D and 3D edges with Sobel detector. Now, how can I separate/extract and fill the rectangle area on the right side of the long vertical line?

Thank you.