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How to perfectly align 2 scanned multiple choice paper images?

Asked by Vic

Vic (view profile)

on 11 Jan 2013

I there a way somehow to align 2 scanned multiple choice paper images? Maybe by using a bar code to auto align them or using a specific shape so i can compare or find the differences in the answers between the two papers?

Thanking you in advance.

0 Comments

Vic

Vic (view profile)

1 Answer

Answer by Image Analyst

Image Analyst (view profile)

on 11 Jan 2013

Yes. See the imregister() function in the Image Processing Toolbox.

5 Comments

Vic

Vic (view profile)

on 12 Jan 2013

ok but I want to aligh this image http://tinypic.com/view.php?pic=2ntjqiq&s=6 to he same position and alignment of this image ( http://tinypic.com/view.php?pic=24pmgbb&s=6 ). I tried the code you have suggested by doing this : fixed = imread('aligned image'); moving = imread('wrongly aligned image');

... but i get some errors

Error using imregister>parseInputs (line 189) Argument 'MovingImage' failed validation with error: Expected input number 2, moving, to be two-dimensional.

Error in imregister (line 92) parsedInputs = parseInputs(varargin{:});

Error in Untitled12 (line 11) movingRegistered = imregister(moving,fixed,'rigid',optimizer,metric);

Any ideas?

Walter Roberson

Walter Roberson (view profile)

on 12 Jan 2013

Convert the images to grayscale before aligning them.

Image Analyst

Image Analyst (view profile)

on 13 Jan 2013

The alignment will probably be the same on a monochrome image as if you could do it on a color image. Just apply the transform you get to all three color channels one at a time and recombine into a color image.

Image Analyst

Image Analyst (view profile)

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