affinetransform

This question is on the OpenCV functions findHomography , getPerspectiveTransform & getAffineTransform What is the difference between findHomography and getPerspectiveTransform ?. My understanding from the documentation is that getPerspectiveTransform computes the transform using 4 correspondences (which is the minimum required to compute a homography/perspective transform) where as findHomography computes the transform even if you provide more than 4 correspondencies (presumably using something like a least squares method?). Is this correct? (In which case the only reason OpenCV still

I got an extended JLabel class where I draw my Map using the code below : the new AffineTransform() is the identity to left my image as it is (0,0,w,h) mygraphics2D = (Graphics2D) getGraphics(); graphics2D.scale(2.0,2.0) ; graphics2D.rotate(.... graphics2D.drawImage(myImageIcon.getImage(),new AffineTransform(), this); now when I click on my JLabel using this event : public void mouseClicked(MouseEvent e) { x =e.getX() ; y = e.getY(); NewX = ???? NewY = ???? } I want to retrieve my new coordinates "the scaled,rotated ... coords" I tried Point2D ptSrc = new Point2D.Double(x, y); Point2D ptDst =

I have one 3D dataset and one 2D dataset which is a slice through the first volume. They are at different scales, resolutions and in a different coordinate system, but of both I know the affine transformation to world coordinates. I then think I know how to apply those, but how do I get an image back from those transformed coordinates again using sinc interpolation? I would like to learn how to perform this/how this works. The first comments below already pointed me at existing functions inside matlab that perform linear interpolation, but I would also like to know how to do this myself so I

I have two planar images A and B I have calculated the homography between these two images using feature points, my question is, if both A and B scale up to double size, let's say A' and B'. How will homography' be? Thank you. The homography doesn't change. It will be the same as long as both images have undergone the same linear scaling. The homography is a mapping between two 2D planes in 3D space. It combines at rotation and translation with the camera matrix. If the position of the camera relative to the object has not changed, then a homography calculated from a mapping of points in the

I'm trying to code a class to seam carve images in x and y direction. The x direction is working, and to reduce the y direction I thought about simply rotating the image 90° and run the same code over the already rescaled image (in x direction only) and after that, rotate it back to its initial state. I found something with AffineTransform and tried it. It actually produced a rotated image, but messed up the colors and I don't know why. This is all the code: import java.awt.image.BufferedImage; import java.awt.geom.AffineTransform; import java.awt.image.AffineTransformOp; import java.io.File;

For a simple vector drawing app I am looking to implement a "Selection Box", that is a graphic representation of the layoutBounds of a Node. Example: example http://i61.tinypic.com/ou4p3t.png Thanks to jewelsea and his BoundsExample , I have a good understanding now on how to get the data for the box. The part I am struggling with is actually drawing the box on the scene, in a way that correctly respects the transformations on the nodes. Correctly in this case means the bounds logical size get scaled with a node, but the stroke of the selection box stays constant. Meaning a selection box