OpenCV Error: Assertion failed (!outImage.empty()) in drawKeypoints, file /tmp/binarydeb/ros-kinetic

SLAM 14讲中学到第七章，在实践时，出现以下报错

OpenCV Error: Assertion failed (!outImage.empty()) in 
drawKeypoints, file /tmp/binarydeb/ros-kinetic-opencv3-3.3.1/
modules/features2d/src/draw.cpp, line 115terminate called 
after throwing an instance of 'cv::Exception'
  what():  /tmp/binarydeb/ros-kinetic-opencv3-
  3.3.1/modules/features2d/src/draw.cpp:115: error:
   (-215) !outImage.empty() in function drawKeypoints

已放弃

原因是文件路径不对，自己运行时是在build下运行的，而两张图片却不在这个目录下，解决办法就是直接将两张图片放到build目录下再运行即可。

得到的部分结果截取如下（与书上实例数据有小出入）

[ INFO:0] Initialize OpenCL runtime...
-- Max dist : 95.000000 
-- Min dist : 7.000000 
一共找到了81组匹配点
fundamental_matrix is 
[5.435453065936354e-06, 0.0001366043242989653, -0.02140890086948144;
 -0.0001321142229824715, 2.339475702778067e-05, -0.006332906454396007;
 0.02107630352202796, -0.003666833952953114, 0.9999999999999999]
essential_matrix is 
[0.01724015832721706, 0.328054335794133, 0.0473747783144249;
 -0.3243229585962962, 0.03292958445202408, -0.6262554366073018;
 -0.005885857752320116, 0.6253830041920333, 0.0153167864909267]
homography_matrix is 
。。。。。。。。。。。