I used findHomography, then:
int solutions = decomposeHomographyMat (H, K, R, T, N);
But this doesn't work properly. Rotation matrix has only "-nan" values. Homography martix is ok. It has values like:
2.44486e-39, 0.0466184, 1.25152e+23
I've tried to use unit matrix instead of homography, but it also didn't work.