how to obtain image boundary of an image?

how to obtain image boundary of an image?

[Youssef Khmou]

Hi Cesar, you have to specify your problem, give an example with per example "circuit.tif" so everyone can work on it instead of image taken from web .

[Cesar]

By example consider an image with 4 birds (bird.tif), and I want to add of of those birds to the same image which now has 5 birds. Let me know if that is clear.

Answer 1

[Image Analyst]

You haven't explained this well enough to answer. The answer could be to use bwperim(), or bwboundaries(), or just to take the first and last row and first and last column. Are you going to explain further what you want?

[Cesar]

I want to perform a boundary operation by which to obtain image boundary on a gray image.

[Image Analyst]

OK, bwboundaries() and bwperim() only work on binary images. So, just do something like this:

leftBoundary = yourImage(:, 1);
rightBoundary = yourImage(:, end);
topBoundary = yourImage(1, :);
bottomBoundary = yourImage(end, :);

[Cesar]

Thanks. The functions do create and display all 4 boundaries of the image. Can that also be done using only 1 function?

[Image Analyst]

Yes, just string them together:

oneBoundary = [yourImage(:,1), yourImage(:,end), yourImage(1,:), yourImage(end,1)];

[Cesar]

I got an error using the string: Error using horzcat CAT arguments dimensions are not consistent.

[Image Analyst]

You need to transpose two of them, because two are row vectors and two are column vectors. Use ' to transpose.

oneBoundary = [yourImage(:,1)', yourImage(:,end)', yourImage(1,:), yourImage(end,1)];

[Cesar]

Thanks. Makes sense.

[Cesar]

Another question. Imagine an image with 4 birds (bird.tif by example), how to add additional bird in the image?

[Image Analyst]

Get a mask for the bird, then do

birds5(binaryMask) = singleBirdImage(binaryMask);

to transfer the bird from the singleBirdImage to the birds5 image.

[Cesar]

img = imread('bird.tif'); IMG = imshow(img); IMG1 = imellipse(gca,[55 10 120 120]); BW = createMask(IMG1,IMG); Will that create the mask for the bird?

[Image Analyst]

Why don't you upload your images of the 4 birds? Where does your single bird come from? A separate image, or is it just one of the 4 that you'd like to copy somewhere else in the image? If you upload your images, then we can cut to the chase and not go back and forth lots of times.

[Cesar]

How do I upload the image?

[Image Analyst]

http://www.mathworks.com/matlabcentral/answers/7924-where-can-i-upload-images-and-files-for-use-on-matlab-answers Or try http://snag.gy or http://www.tinypic.com

[Cesar]

Done

[Image Analyst]

Uh, OK.

[Cesar]

Any update?

[Image Analyst]

On what?

[Cesar]

After uploading the image, do you have an answer?

[Image Analyst]

What image? You didn't tell me the location of any image. Please review your postings from my point of view. Does anyone have enough information to help you?

[Cesar]

Why don't you upload your images of the 4 birds? Where does your single bird come from? A separate image, or is it just one of the 4 that you'd like to copy somewhere else in the image? If you upload your images, then we can cut to the chase and not go back and forth lots of times.

I did upload an image at http://www.tinypic.com. Do you want me to re-upload it?

[Cesar]

Imagine an image with 4 objects, how to add an additional object in the image? That was my question. I uploaded an image with 4 objects at http://www.tinypic.com.

[Cesar]

What about now?

[Image Analyst]

And exactly how am I supposed to find your images? tinypic.com is a big web site.

[Cesar]

Where can I send you the image?

[Image Analyst]

You don't need to send it. Just tell me its URL so we can find it.

[Cesar]

http://tinypic.com/r/swftz9/6