参考：【OpenCV】双目测距（双目标定、双目校正和立体匹配）

/*****描述：鼠标操作回调函数定义*****/
static void onMouse(int event, int x, int y, int, void*)
{if (selectObject){selection.x = MIN(x, origin.x);selection.y = MIN(y, origin.y);selection.width = std::abs(x - origin.x);selection.height = std::abs(y - origin.y);}switch (event){case EVENT_LBUTTONDOWN:   //鼠标左按钮按下的事件origin = Point(x, y);selection = Rect(x, y, 0, 0);selectObject = true;cout << origin <<"in world coordinate is: " << xyz.at<Vec3f>(origin) << endl;break;case EVENT_LBUTTONUP:    //鼠标左按钮释放的事件selectObject = false;if (selection.width > 0 && selection.height > 0)break;}
}// 函数调用
//鼠标响应函数setMouseCallback(窗口名称, 鼠标回调函数, 传给回调函数的参数，一般取0)
setMouseCallback("disparity", onMouse, 0);