Projection of an Image

37 vues (au cours des 30 derniers jours)
Logan Davis
Logan Davis le 13 Déc 2017
If I know the four corners of a rectangle that has been projected, how can I obtain a top-down view of that image using image projection. I tried to use fitgeotrans and imwarp but did not obtain the correct results. Below is the code I used:
U = double([topLeft; topRight; bottomRight; bottomLeft]);
topLeftNew = [1 1];
topRightNew = [1 width];
bottomLeftNew = [height 1];
bottomRightNew = [height width];
X = double([topLeftNew; topRightNew; bottomRightNew; bottomLeftNew]);
tform = fitgeotrans(U, X, 'projective');
B = imwarp(orig, tform);
Does anyone know what I could do to fix this or a different method? The image I'm trying to transform is:
The four corners I've obtained are shown as well. The result of the transformation is.
I'd like for the result to only contain the notecard and orient it correctly upright as well. Is this possible and how can I go about achieving this?

Réponses (2)

Ben Drebing
Ben Drebing le 21 Déc 2017
I think that the orderings of your fixedpoints and movingpoints do not match up. Try
topLeft = [360, 546];
topRight = [609, 109];
botRight = [873, 240];
botLeft = [645, 703];
U = [topLeft; topRight; botRight; botLeft];
width = size(I,2);
height = size(I,1);
topLeftNew = [1 1];
topRightNew = [1 width];
bottomLeftNew = [height 1];
bottomRightNew = [height width];
X = double([topLeftNew;bottomLeftNew; bottomRightNew; topRightNew ]);
tform = fitgeotrans(U, X, 'projective');
B = imwarp(I, tform);
imshow(B,[]);
You can use imcrop to crop out the rest of the image.
  1 commentaire
Masoud Heidari
Masoud Heidari le 5 Mar 2021
Thank you very much Ben! it was a big help for me too.

Connectez-vous pour commenter.


Image Analyst
Image Analyst le 21 Déc 2017
See attached demo.

Catégories

En savoir plus sur Images dans Help Center et File Exchange

Community Treasure Hunt

Find the treasures in MATLAB Central and discover how the community can help you!

Start Hunting!

Translated by