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struggling with shifting an image using non-integer offset

Asked by Alex

Alex (view profile)

on 12 May 2013
Accepted Answer by Matt J

Matt J (view profile)

I am not sure I understand the fact that the image's resolution 1500x2000 (integer values) pixels and offset_X = -3.0314 and offset_Y = 1.2432.

How to go about shifting the image taking into account the offset?



Alex (view profile)

1 Answer

Answer by Matt J

Matt J (view profile)

on 12 May 2013
Accepted answer

Use IMTRANSFORM, griddedInterpolant(), or INTERP2.



Alex (view profile)

on 12 May 2013

Thank you for the advice. Could you please, correct the code below based on interp2. Let's say I have an image (size 971x1471) assigned to variable Im. Offset for this image is offset_X = -3.0314 and offset_Y = 1.2432. I need to get the image ImC (corrected image shifted using the offset above). After reading about interp2 I came up with the next code with MATLAB error message leaping at me. Please, guide me here.

[xx,yy] = ndgrid(1:971,1:1471);
xx = xx(:);
yy = yy(:);
xxShifted = xx + offset_X;
yyShifted = yy + offset_Y;
ImC(:) = interp2(xx,yy,Im(:),xxShifted,yyShifted);

Error using griddedInterpolant The grid vectors are not strictly monotonic increasing.

Error in interp2/makegriddedinterp (line 220) F = griddedInterpolant(varargin{:});

Error in interp2 (line 125) F = makegriddedinterp({X, Y}, V, method);

Bjorn Gustavsson

Bjorn Gustavsson (view profile)

on 13 May 2013

You dont need to (:) xx, yy and Im just send them into interp2 as they are.

Matt J

Matt J (view profile)

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