homography

Extract projective homography from two Kinect depth maps

女生的网名这么多〃 提交于 2019-11-30 08:43:56
Given two consecutive 3D point clouds 1 and 2 (not the whole cloud, say 100 points selected from the cloud with OpenCV's GoodFeaturesToMatch), obtained from a Kinect depthmap, I want to compute camera's homography from 1 to 2. I understand that this a projective transform, and it has already been done by many people: here (slide 12) , here (slide 30) and here in what seems to be the classic paper . My problem is that whilst I'm a competent programmer, I haven't got the math or trig skills to turn one of those methods into code. As this is not an easy problem, I offer a large bounty for the

How to calculate Rotation and Translation matrices from homography?

一世执手 提交于 2019-11-30 07:42:06
I have already done the comparison of 2 images of same scene which are taken by one camera with different view angles(say left and right) using SURF in emgucv (C#). And it gave me a 3x3 homography matrix for 2D transformation. But now I want to make those 2 images in 3D environment (using DirectX). To do that I need to calculate relative location and orientation of 2nd image(right) to the 1st image(left) in 3D form. How can I calculate Rotation and Translate matrices for 2nd image? I need also z value for 2nd image. I read something called 'Homograhy decomposition'. Is it the way? Is there

Opencv homography to find global xy coordinates from pixel xy coordinates

╄→尐↘猪︶ㄣ 提交于 2019-11-30 07:39:25
问题 I am trying to find the transformation matrix H so that i can multiply the (x,y) pixel coordinates and get the (x,y) real world coordinates. Here is my code: import cv2 import numpy as np from numpy.linalg import inv if __name__ == '__main__' : D=[159.1,34.2] I=[497.3,37.5] G=[639.3,479.7] A=[0,478.2] # Read source image. im_src = cv2.imread('/home/vivek/june_14.png') # Four corners of the book in source image pts_src = np.array([D,I,G,A]) # Read destination image. im_dst = cv2.imread('/home

OpenCV C++ findHomography mask values meaning

人走茶凉 提交于 2019-11-30 07:25:58
I am using the function findHomography of OpenCV with the RANSAC method in order to find the homography that relates two images linked with a set of keypoints. Main issue is that I haven’t been able to find anywhere yet what are the values of the mask matrix that the function outputs. Only information that I know is that 0 values are outliers, and non zero values are inliers. But what does it mean the inliers value? Anyone knows? Thanks in advance! Piece of code where I call findHomography : cv::Mat H12; cv::Mat mask; H12 = cv::findHomography(FvPointsIm1, FvPointsIm2, mask, CV_RANSAC, 5); ui-

Camera pose estimation from homography or with solvePnP() function

流过昼夜 提交于 2019-11-30 07:02:25
问题 I'm trying to build static augmented reality scene over a photo with 4 defined correspondences between coplanar points on a plane and image. Here is a step by step flow: User adds an image using device's camera. Let's assume it contains a rectangle captured with some perspective. User defines physical size of the rectangle, which lies in horizontal plane (YOZ in terms of SceneKit). Let's assume it's center is world's origin (0, 0, 0), so we can easily find (x,y,z) for each corner. User

Multiple camera image stitching

余生长醉 提交于 2019-11-30 05:25:32
I've been running a project of stitching images from multiple cameras, but I think I've got a bottleneck...I have some questions about this issue. I wanna try to mount them on a vehicle in the future and that means the relative positions and orientations of cameras are FIXED. Also, as I'm using multiple cameras and try to stitch images from them using HOMOGRAPHY, I'll put cameras as close as possible so that the errors(due to the fact that the foci of the cameras are not at the same position and it's impossible as cameras occupy certain space.) can be reduced. Here's a short experiment video

4-point transform images

不问归期 提交于 2019-11-30 05:03:07
问题 I need to transform bitmap images with their 4 corner points moved from one location to another. Any code that can run on Windows, C#/VB.NET preferably, even help how to use scriptable programs like Paint.NET or Photoshop would be accepted. The Java Advanced Imaging API sounds hopeful. I need it for a screenshot manipulation system, which allows you to get such effects: (source: wholetomato.com) 回答1: Check out the Perspective warping examples from ImageMagick. It is available for most

OpenCV Homography, Transform a point, what is this code doing?

被刻印的时光 ゝ 提交于 2019-11-29 22:30:33
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 are greatly appreciated :) double h[9]; homography = cvMat(3, 3, CV_64F, h); CvMat ps1 = cvMat(MAX

findHomography, getPerspectiveTransform, & getAffineTransform

断了今生、忘了曾经 提交于 2019-11-29 20:58:09
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

Extract projective homography from two Kinect depth maps

情到浓时终转凉″ 提交于 2019-11-29 11:43:12
问题 Given two consecutive 3D point clouds 1 and 2 (not the whole cloud, say 100 points selected from the cloud with OpenCV's GoodFeaturesToMatch), obtained from a Kinect depthmap, I want to compute camera's homography from 1 to 2. I understand that this a projective transform, and it has already been done by many people: here (slide 12), here (slide 30) and here in what seems to be the classic paper. My problem is that whilst I'm a competent programmer, I haven't got the math or trig skills to