当一个物体边与坐标轴平行时，生成的ABB最小外接立方体有偏差，故这里采用AABB算法。

示例代码：

#include <pcl/features/moment_of_inertia_estimation.h>
#include <vector>
#include <pcl/io/pcd_io.h>
#include <pcl/point_types.h>
#include <pcl/visualization/cloud_viewer.h>
#include <boost/thread/thread.hpp>

int main()
{
    pcl::PointCloud<pcl::PointXYZ>::Ptr down_cloud(new pcl::PointCloud<pcl::PointXYZ>);
    if (pcl::io::loadPCDFile("..\\testdata\\point0823-1.pcd", *down_cloud) == -1)
        return (-1);
    vector<double> down = calculate_AABB(down_cloud);
}

vector<double> calculate_AABB(pcl::PointCloud<pcl::PointXYZ>::Ptr cloud)
{
	//实例化一个Momentof...
	pcl::MomentOfInertiaEstimation <pcl::PointXYZ> feature_extractor;
	feature_extractor.setInputCloud(cloud);
	feature_extractor.compute();
	//声明一些必要的变量
	std::vector <float> moment_of_inertia;
	std::vector <float> eccentricity;
	pcl::PointXYZ min_point_AABB;
	pcl::PointXYZ max_point_AABB;
	
	//计算描述符和其他的特征
	feature_extractor.getMomentOfInertia(moment_of_inertia);
	feature_extractor.getEccentricity(eccentricity);
	feature_extractor.getAABB(min_point_AABB, max_point_AABB);

	//显示
	boost::shared_ptr<pcl::visualization::PCLVisualizer> viewer(new pcl::visualization::PCLVisualizer("3D Viewer"));
	viewer->setBackgroundColor(0, 0, 0);
	viewer->addCoordinateSystem(1.0);
	viewer->initCameraParameters();
	viewer->addPointCloud<pcl::PointXYZ>(cloud, "sample cloud");
	//addCube
	viewer->addCube(min_point_AABB.x, max_point_AABB.x, min_point_AABB.y, max_point_AABB.y, min_point_AABB.z, max_point_AABB.z, 1.0, 1.0, 0.0, "AABB");//AABB盒子

	viewer->setRepresentationToWireframeForAllActors();//线框模式
	viewer->resetCameraViewpoint();

	cout << min_point_AABB.x << endl;
	cout << min_point_AABB.y << endl;
	cout << max_point_AABB.x << endl;
	cout << max_point_AABB.y << endl;

	while (!viewer->wasStopped())
	{
		viewer->spinOnce(100);
		boost::this_thread::sleep(boost::posix_time::microseconds(100000));
	}

	return { min_point_AABB.x, max_point_AABB.x, min_point_AABB.y, max_point_AABB.y };
}

测试效果：