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How to transform given XY coordinates using 'lwm' tform?

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Sudip Paudel
Sudip Paudel on 6 Jul 2020
Commented: Sudip Paudel on 6 Jul 2020
Hi, I have a set of XY coordinates, how do we transform given XY coordinates using 'lwm' tform?
ROI_Coordinates_XY=[1,2; 2,3; 4,5; 6,7; 1,0; 1,6]; %XY coordinates that need to be transformed
img1=imread('img1');
img2=imread('img2');
cpselect(img1, img2) %selecting control points
keyboard
img1_coordinates=movingPoints; clear movingPoints %save control points
img2_coordinates=fixedPoints;clear fixedPoints %save fixed points
tform_LWM = fitgeotrans(img1_coordinates, img2_coordinates, 'lwm', 10); %calculate tform using 'lwm'
%Tranform ROI_Coordinates_XY using the same tform_LWM.
tform_ed_XY = Help_function (tform_LWM, ROI_Coordinates_XY);
%I am looking for a function like transformPointsForward for tform_LWM.
Thank you for your help.

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Accepted Answer

Matt J
Matt J on 6 Jul 2020
Edited: Matt J on 6 Jul 2020
A forward version of the lwm transform is not provided because it is not guaranteed to be a 1-1 transformation, but perhaps it would be useful to you simply to do the inverse fit
tform_inv = fitgeotrans(img2_coordinates, img1_coordinates, 'lwm', 10);
and then apply transformPointsInverse.

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