drawCross          79 samples/cpp/kalman.cpp             drawCross( statePt, Scalar(255,255,255), 3 );
drawCross          80 samples/cpp/kalman.cpp             drawCross( measPt, Scalar(0,0,255), 3 );
drawCross          81 samples/cpp/kalman.cpp             drawCross( predictPt, Scalar(0,255,0), 3 );