opencv/doc/tutorials/features2d/feature_homography/feature_homography.markdown
Alexander Alekhin 45dd575ed2 Merge remote-tracking branch 'upstream/3.4' into merge-3.4
Revert "documentation: avoid links to 'master' branch from 3.4 maintenance branch"
This reverts commit 9ba9358ecb.

Revert "documentation: avoid links to 'master' branch from 3.4 maintenance branch (2)"
This reverts commit f185802489.
2018-06-04 19:26:10 +03:00

1.9 KiB

Features2D + Homography to find a known object

Goal

In this tutorial you will learn how to:

  • Use the function @ref cv::findHomography to find the transform between matched keypoints.
  • Use the function @ref cv::perspectiveTransform to map the points.

\warning You need the OpenCV contrib modules to be able to use the SURF features (alternatives are ORB, KAZE, ... features).

Theory

Code

@add_toggle_cpp This tutorial code's is shown lines below. You can also download it from here @include samples/cpp/tutorial_code/features2D/feature_homography/SURF_FLANN_matching_homography_Demo.cpp @end_toggle

@add_toggle_java This tutorial code's is shown lines below. You can also download it from here @include samples/java/tutorial_code/features2D/feature_homography/SURFFLANNMatchingHomographyDemo.java @end_toggle

@add_toggle_python This tutorial code's is shown lines below. You can also download it from here @include samples/python/tutorial_code/features2D/feature_homography/SURF_FLANN_matching_homography_Demo.py @end_toggle

Explanation

Result

  • And here is the result for the detected object (highlighted in green). Note that since the homography is estimated with a RANSAC approach, detected false matches will not impact the homography calculation.