How to retain the size of image when we rotate image?

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binbin cui 2016-8-6

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评论： binbin cui 2016-8-6

I was using the imrotate to rotate an image B = imrotate( image,20) and the image was rotated. After certain manipulations, I wanted to make it back to its original image, so I used C = imrotate(B,-20). But I find the size of image C is changed, which is bigger than original image. And the original image lies in the center of image C .Does anyone know how to ensure the size of the image exactly same as the original image after the twice rotation?

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binbin cui 2016-8-6

In fact, I wanna get the exact original image after rotation.

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Image Analyst 2016-8-6

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When it rotates, it enlarges the canvas. You'll have to store the original size so that you can crop it after a round trip rotation. Like if it was 1000 rows, then after rotation it was 1200 rows tall, then when you rotate it back you need to crop off 100 rows from the top and bottom. Same for the right and left sides. I'm sure you can handle the math. Let me know if you can't.