System information (version)

• OpenCV => 3.4.0-dev
• Operating System / Platform => ALL
• Compiler => ALL

Detailed description

Cannot set the first level in the ORB detector to any value other than zero.
Setting it to any positive number i is supposed to make all octaves below i enlarged, rather than
the usual shrinkage (similar to SIFT negative octaves).

Steps to reproduce

vector<KeyPoint> kps;
Mat img = imread("any_image.png"), descs;
Ptr<ORB> orb = ORB::create();

orb->setFirstLevel(1); // <- Crash ahead!
orb->detectAndCompute(img, noArray(), kps, descs);

Actual result

CRASH!