Asagidaki hatanin sebebi buyuk ihtimalle ya resimde "keypoint" bulunamamasi ya da "Visual Vocabulary"nin yuklenememesi.

OpenCV Error: Assertion failed (queryDescriptors.type() == trainDescCollection[0].type()) in knnMatchImpl, file /tmp/opencv-Ca0QEw/opencv-2.4.9/modules/features2d/src/matchers.cpp, line 351

libc++abi.dylib: terminating with uncaught exception of type cv::Exception: /tmp/opencv-Ca0QEw/opencv-2.4.9/modules/features2d/src/matchers.cpp:351: error: (-215) queryDescriptors.type() == trainDescCollection[0].type() in function knnMatchImpl