OpenCV3.1 xfeatures2d::SIFT 使用

OpenCV3.1 SIFT使用

OpenCV3对OpenCV的模块进行了调整，将开发中与nofree模块放在 了OpenCV_contrib中（包含SIFT），gitHub上的官方项目分成了两个，opencv 与 opencv_contrib。所以，要使用sift接口需在opencv3.1基础上，再安装opencv_contrib。本文主要记录如何安装opencv_contrib，配置Xcode，sift接口的用法。
环境：OSX + Xcode + OpenCV3.1

install opencv_contrib

• download contrib source code https://github.com/Itseez/opencv_contrib, follow README.md to install

$ cd 
$ cmake -DOPENCV_EXTRA_MODULES_PATH=/modules 
$ make -j5
$ sudo make install

Where and is directory in opencv3.1 install tutorial

configuration Xcode

like How to develop OpenCV with Xcode

pro_name Build Setting > Search Paths

• /usr/local/lib
• /usr/local/include

pro_name Build Setting >Other Linker Flags

• -lopencv_stitching -lopencv_superres -lopencv_videostab -lopencv_aruco -lopencv_bgsegm -lopencv_bioinspired -lopencv_ccalib -lopencv_dnn -lopencv_dpm -lopencv_fuzzy -lopencv_line_descriptor -lopencv_optflow -lopencv_plot -lopencv_reg -lopencv_saliency -lopencv_stereo -lopencv_structured_light -lopencv_rgbd -lopencv_surface_matching -lopencv_tracking -lopencv_datasets -lopencv_text -lopencv_face -lopencv_xfeatures2d -lopencv_shape -lopencv_video -lopencv_ximgproc -lopencv_calib3d -lopencv_features2d -lopencv_flann -lopencv_xobjdetect -lopencv_objdetect -lopencv_ml -lopencv_xphoto -lippicv -lopencv_highgui -lopencv_videoio -lopencv_imgcodecs -lopencv_photo -lopencv_imgproc -lopencv_core

sample of sift

• sample in (souce_dir)/samples/cpp/tutorial_code/xfeatures2D/LATCH_match.cpp or bellow

  
  #include "opencv2/xfeatures2d.hpp"
  
  
  // 
  // now, you can no more create an instance on the 'stack', like in the tutorial
  // (yea, noticed for a fix/pr).
  // you will have to use cv::Ptr all the way down:
  //
  cv::Ptr f2d = xfeatures2d::SIFT::create();
  //cv::Ptr f2d = xfeatures2d::SURF::create();
  //cv::Ptr f2d = ORB::create();
  // you get the picture, i hope..
  
  //-- Step 1: Detect the keypoints:
  std::vector keypoints_1, keypoints_2;    
  f2d->detect( img_1, keypoints_1 );
  f2d->detect( img_2, keypoints_2 );
  
  //-- Step 2: Calculate descriptors (feature vectors)    
  Mat descriptors_1, descriptors_2;    
  f2d->compute( img_1, keypoints_1, descriptors_1 );
  f2d->compute( img_2, keypoints_2, descriptors_2 );
  
  //-- Step 3: Matching descriptor vectors using BFMatcher :
  BFMatcher matcher;
  std::vector< DMatch > matches;
  matcher.match( descriptors_1, descriptors_2, matches );

References

https://github.com/Itseez/opencv_contrib
https://github.com/Itseez/opencv
http://blog.csdn.net/lijiang1991/article/details/50756065
http://docs.opencv.org/3.1.0/d5/d3c/classcv_1_1xfeatures2d_1_1SIFT.html#gsc.tab=0