homography

问题 I am able to track 4 coordinates over different images of the same scene by calculating a 3x3 homography between them. Doing this I can overlay other 2D images onto these coordinates. I am wondering if I could use this homography to augment a cube onto this position instead using opengl? I think the 3x3 matrix doesn't give enough information but if I know the camera calibration matrix can I get enough to create a model view matrix to do this? Thank you for any help you can give. 回答1: If you

问题 The example in the link below is using findHomography to get the transformation between two sets of points. I want to limit the degrees of freedom used in the transformation so want to replace findHomography with estimateRigidTransform . http://docs.opencv.org/doc/tutorials/features2d/feature_homography/feature_homography.html#feature-homography Below I use estimateRigidTransform to get the transformation between the object and scene points. objPoints and scePoints are represented by vector

问题 Hi i am a beginner in computer vision and i wish to know what exactly is the difference between a homography and affine tranformation, if you want to find the translation between two images which one would you use and why?. From papers and definitions I found online, I am yet to find the difference between them and where one is used instead of the other. Thanks for your help. 回答1: I have set it down in the terms of a layman. Homography A homography, is a matrix that maps a given set of points

问题 I am trying to transform an image along the edge of the object (here the object is the book). Using canny edge detection, I am detecting the edges and from the score matrix, based on pixel value, I am choosing a random 4 coordinates lying on the edge for transformation. But the transformation is not as it thought it would be. What is the problem/Where am I missing out? First I have sliced out a portion of the image. Then applied canny edge detection and randomly selected 4 edge coordinate

问题 I'm working on a android application and I need to estimate online camera rotation in 3D-plan using images from camera and opencv library. I like to calculate Euler angles. I have read this and this page and I can estimate homography matrix like here. My first question is, should I really know the camera intrinsic matrix from camera calibrtion or is the homography matrix (camera extrinsic) enough to estimate euler angles (pitch, roll, yaw)? If homography matrix is enough, how can I do it

问题 Libs: OpenCV Target: Android (OpenCV4Android) I try to compute the Homography of a world plane (e.g. monitor screen) to get the camera pose, transform it and reproject the points back for tracking tasks. I'm using OpenCVs findHomography() / getPerspectiveTransform() to get the homography. The reprojection of the points using perspectiveTransform() (as explained here: http://docs.opencv.org/doc/tutorials/features2d/feature_homography/feature_homography.html) which works pretty well. The

问题 I'm working with a homography calculated by OpenCV. I currently use this homography to transform points using the function below. This function performs the task I require however I have no clue how it actually works. Can anyone explain, line by line exactly, the logic/theory behind the last 3 lines of code, I understand that this transforms the point x,y but I'm unclear as to why this works: Why are Z , px and py calculated in this way, what do the elements in h correspond to? Your comments

问题 I'm working with a homography calculated by OpenCV. I currently use this homography to transform points using the function below. This function performs the task I require however I have no clue how it actually works. Can anyone explain, line by line exactly, the logic/theory behind the last 3 lines of code, I understand that this transforms the point x,y but I'm unclear as to why this works: Why are Z , px and py calculated in this way, what do the elements in h correspond to? Your comments

问题 I'm working with a homography calculated by OpenCV. I currently use this homography to transform points using the function below. This function performs the task I require however I have no clue how it actually works. Can anyone explain, line by line exactly, the logic/theory behind the last 3 lines of code, I understand that this transforms the point x,y but I'm unclear as to why this works: Why are Z , px and py calculated in this way, what do the elements in h correspond to? Your comments

问题 can somebody help me, how we can calculate the new positions of keypoints in the transformed image,the keypoints were detected in original image. I am using opencv homography matrix and warpPerspective to make the transformed image. Here is a code.. ... std::vector< Point2f > points1,points2; for( int i = 0; i < matches1.size(); i++ ) { points1.push_back( keypoints_input1[matches1[i].queryIdx ].pt ); points2.push_back( keypoints_input2[matches1[i].trainIdx ].pt ); } /* Find the Homography