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how to crop a particular location of a image?

Asked by Sivakumaran Chandrasekaran on 11 Sep 2012

I have drawn a star on a image and i want to crop that star region alone. How to do it?

2 Comments

Andrei Bobrov on 11 Sep 2012

use function crop from Image Processing Toolbox

KIRAN kumar on 18 Jan 2013

select the area first by selecting the star by defining it then perform corp.u can use image segmentation process for this

Sivakumaran Chandrasekaran

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2 Answers

Answer by Image Analyst on 18 Jan 2013
Accepted answer

Use max() and min() to find the extremes of the coordinates you drew. Then you can create a box and use imcrop(). You know that cropping gives you a matrix which is a rectangular shape, right?

0 Comments

Image Analyst
Answer by Walter Roberson on 18 Jan 2013

poly2mask() and use the resulting mask to extract pixels from the image. You will probably also want to calculate the bounding box of the mask and create a rectangular area that size to store the extracted pixels in (as it is not possible to have a matrix which is an irregular shape.)

3 Comments

Image Analyst on 18 Jan 2013

Just noticed this was 4 months old. I have no idea how both of us could have missed it back then.

Walter Roberson on 18 Jan 2013

I saw it back then but I was busy and I figured someone else would answer.

Even though it is late, I thank you both Image Analyst and Walter.

Walter Roberson

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