Re: Advise on object detection

On May 21, 8:48 pm, ImageAnalyst <imageanal...@xxxxxxxxxxxxxx> wrote:
On May 21, 4:35 am, stormogulen <bjarn...@xxxxxxxxx> wrote:



Hi all,

I have a bunch of pictures like this one:

(http://cid-1627b3c28e2dc281.spaces.live.com/photos/cns!
1627B3C28E2DC281!125 )

(A picture of rocks with soil between them)

I would like to detect and extract every single rock in the picture.
What would be the best way to do this? I have tried using Canny edge
detection to find each rock, but even though the contrast between rock
and soil is quite high, I don't get all the edges in the picture.

Also I would like to find the green box which is somewhere at the
center of the picture. How would you suggest that I do that?

Best regards,
Bjarne

---------------------------------------------------------------------------­-----
Bjarne:
An edge detector depends on the window size so it will find large dirt
areas in addition to the dirt cracks between the rocks.  You might try
just simple thresholding and then maybe a morphological opening to
make the dirt connect in the narrow spots.  Or you could use the edge
detector but to have it not find the large dirt spots, you need to
check your areas against their average intensity and then thrown out
regions close to the dirt color.   Doesn't really look too tough to do
a reasonably good job. Find the green box with a color classifier, for
example just convert the RGB image into HSI and threshold on the hue
channel.
Regards,
ImageAnalyst- Hide quoted text -

- Show quoted text -

I agree with ImageAnalyst.

Do you have MATLAB with image processing toolbox? It has a
demonstration project called 'Marker-Controlled Watershed
Segmentation'. That could be one way of achieving what you want to do
with the rocks. All the steps invole either morphological operations
or thresholding.

For the box, a color classifier makes sense. You may also use a hough
transform for lines.

Again, there can be multiple ways of doing this. You have to choose
based on your requirements.
.

Relevant Pages

  • Re: The origin of water
    ... down with a splosh as the whole earth was covered in water. ... mixture of sand and rock and clay and everything that we walk on every ... Let's stick to dirt for now. ... This is the rock and roll theory of the origin of water. ...
    (talk.origins)
  • Re: The origin of water
    ... down with a splosh as the whole earth was covered in water. ... mixture of sand and rock and clay and everything that we walk on every ... Let's stick to dirt for now. ... Now there are folks, creationists of a sort, who claim that God ...
    (talk.origins)
  • Re: Advise on object detection
    ... I would like to detect and extract every single rock in the picture. ... and soil is quite high, I don't get all the edges in the picture. ... An edge detector depends on the window size so it will find large dirt ...
    (sci.image.processing)
  • Re: Fixing my home driveway ditch drain? ~ Thanks for advice!!
    ... the rock and dirt that goes over my ditch. ... I can see that the two pipes underground ... down the hole until it starts oozing around the liner. ...
    (alt.home.repair)