这次我们将学着怎么从一个深度图里面导出边界。我们对3种不同种类的点很感兴趣:物体的边框的点,阴影边框点,和面纱点(在障碍物边界和阴影边界),这是一个很典型的现象在通过雷达获取的3D深度。
下面是代码
/* \author Bastian Steder */ #include <iostream> #include <boost/thread/thread.hpp> #include <pcl/range_image/range_image.h> #include <pcl/io/pcd_io.h> #include <pcl/visualization/range_image_visualizer.h> #include <pcl/visualization/pcl_visualizer.h> #include <pcl/features/range_image_border_extractor.h> #include <pcl/console/parse.h> typedef pcl::PointXYZ PointType; // -------------------- // -----Parameters----- // -------------------- float angular_resolution = 0.5f; pcl::RangeImage::CoordinateFrame coordinate_frame = pcl::RangeImage::CAMERA_FRAME; bool setUnseenToMaxRange = false; // -------------- // -----Help----- // -------------- void printUsage (const char* progName) { std::cout << "\n\nUsage: "<<progName<<" [options] <scene.pcd>\n\n" << "Options:\n" << "-------------------------------------------\n" << "-r <float> angular resolution in degrees (default "<<angular_resolution<<")\n" << "-c <int> coordinate frame (default "<< (int)coordinate_frame<<")\n" << "-m Treat all unseen points to max range\n" << "-h this help\n" << "\n\n"; } // -------------- // -----Main----- // -------------- int main (int argc, char** argv) { // -------------------------------------- // -----Parse Command Line Arguments----- // -------------------------------------- if (pcl::console::find_argument (argc, argv, "-h") >= 0) { printUsage (argv[0]); return 0; } if (pcl::console::find_argument (argc, argv, "-m") >= 0) { setUnseenToMaxRange = true; cout << "Setting unseen values in range image to maximum range readings.\n"; } int tmp_coordinate_frame; if (pcl::console::parse (argc, argv, "-c", tmp_coordinate_frame) >= 0) { coordinate_frame = pcl::RangeImage::CoordinateFrame (tmp_coordinate_frame); cout << "Using coordinate frame "<< (int)coordinate_frame<<".\n"; } if (pcl::console::parse (argc, argv, "-r", angular_resolution) >= 0) cout << "Setting angular resolution to "<<angular_resolution<<"deg.\n"; angular_resolution = pcl::deg2rad (angular_resolution); // ------------------------------------------------------------------ // -----Read pcd file or create example point cloud if not given----- // ------------------------------------------------------------------ pcl::PointCloud<PointType>::Ptr point_cloud_ptr (new pcl::PointCloud<PointType>); pcl::PointCloud<PointType>& point_cloud = *point_cloud_ptr; pcl::PointCloud<pcl::PointWithViewpoint> far_ranges; Eigen::Affine3f scene_sensor_pose (Eigen::Affine3f::Identity ()); std::vector<int> pcd_filename_indices = pcl::console::parse_file_extension_argument (argc, argv, "pcd"); if (!pcd_filename_indices.empty ()) { std::string filename = argv[pcd_filename_indices[0]]; if (pcl::io::loadPCDFile (filename, point_cloud) == -1) { cout << "Was not able to open file \""<<filename<<"\".\n"; printUsage (argv[0]); return 0; } scene_sensor_pose = Eigen::Affine3f (Eigen::Translation3f (point_cloud.sensor_origin_[0], point_cloud.sensor_origin_[1], point_cloud.sensor_origin_[2])) * Eigen::Affine3f (point_cloud.sensor_orientation_); std::string far_ranges_filename = pcl::getFilenameWithoutExtension (filename)+"_far_ranges.pcd"; if (pcl::io::loadPCDFile(far_ranges_filename.c_str(), far_ranges) == -1) std::cout << "Far ranges file \""<<far_ranges_filename<<"\" does not exists.\n"; } else { cout << "\nNo *.pcd file given => Genarating example point cloud.\n\n"; for (float x=-0.5f; x<=0.5f; x+=0.01f) { for (float y=-0.5f; y<=0.5f; y+=0.01f) { PointType point; point.x = x; point.y = y; point.z = 2.0f - y; point_cloud.points.push_back (point); } } point_cloud.width = (int) point_cloud.points.size (); point_cloud.height = 1; } // ----------------------------------------------- // -----Create RangeImage from the PointCloud----- // ----------------------------------------------- float noise_level = 0.0; float min_range = 0.0f; int border_size = 1; boost::shared_ptr<pcl::RangeImage> range_image_ptr (new pcl::RangeImage); pcl::RangeImage& range_image = *range_image_ptr; range_image.createFromPointCloud (point_cloud, angular_resolution, pcl::deg2rad (360.0f), pcl::deg2rad (180.0f), scene_sensor_pose, coordinate_frame, noise_level, min_range, border_size); range_image.integrateFarRanges (far_ranges); if (setUnseenToMaxRange) range_image.setUnseenToMaxRange (); // -------------------------------------------- // -----Open 3D viewer and add point cloud----- // -------------------------------------------- pcl::visualization::PCLVisualizer viewer ("3D Viewer"); viewer.setBackgroundColor (1, 1, 1); viewer.addCoordinateSystem (1.0f, "global"); pcl::visualization::PointCloudColorHandlerCustom<PointType> point_cloud_color_handler (point_cloud_ptr, 0, 0, 0); viewer.addPointCloud (point_cloud_ptr, point_cloud_color_handler, "original point cloud"); //PointCloudColorHandlerCustom<pcl::PointWithRange> range_image_color_handler (range_image_ptr, 150, 150, 150); //viewer.addPointCloud (range_image_ptr, range_image_color_handler, "range image"); //viewer.setPointCloudRenderingProperties (PCL_VISUALIZER_POINT_SIZE, 2, "range image"); // ------------------------- // -----Extract borders----- // ------------------------- pcl::RangeImageBorderExtractor border_extractor (&range_image); pcl::PointCloud<pcl::BorderDescription> border_descriptions; border_extractor.compute (border_descriptions); // ---------------------------------- // -----Show points in 3D viewer----- // ---------------------------------- pcl::PointCloud<pcl::PointWithRange>::Ptr border_points_ptr(new pcl::PointCloud<pcl::PointWithRange>), veil_points_ptr(new pcl::PointCloud<pcl::PointWithRange>), shadow_points_ptr(new pcl::PointCloud<pcl::PointWithRange>); pcl::PointCloud<pcl::PointWithRange>& border_points = *border_points_ptr, & veil_points = * veil_points_ptr, & shadow_points = *shadow_points_ptr; for (int y=0; y< (int)range_image.height; ++y) { for (int x=0; x< (int)range_image.width; ++x) { if (border_descriptions.points[y*range_image.width + x].traits[pcl::BORDER_TRAIT__OBSTACLE_BORDER]) border_points.points.push_back (range_image.points[y*range_image.width + x]); if (border_descriptions.points[y*range_image.width + x].traits[pcl::BORDER_TRAIT__VEIL_POINT]) veil_points.points.push_back (range_image.points[y*range_image.width + x]); if (border_descriptions.points[y*range_image.width + x].traits[pcl::BORDER_TRAIT__SHADOW_BORDER]) shadow_points.points.push_back (range_image.points[y*range_image.width + x]); } } pcl::visualization::PointCloudColorHandlerCustom<pcl::PointWithRange> border_points_color_handler (border_points_ptr, 0, 255, 0); viewer.addPointCloud<pcl::PointWithRange> (border_points_ptr, border_points_color_handler, "border points"); viewer.setPointCloudRenderingProperties (pcl::visualization::PCL_VISUALIZER_POINT_SIZE, 7, "border points"); pcl::visualization::PointCloudColorHandlerCustom<pcl::PointWithRange> veil_points_color_handler (veil_points_ptr, 255, 0, 0); viewer.addPointCloud<pcl::PointWithRange> (veil_points_ptr, veil_points_color_handler, "veil points"); viewer.setPointCloudRenderingProperties (pcl::visualization::PCL_VISUALIZER_POINT_SIZE, 7, "veil points"); pcl::visualization::PointCloudColorHandlerCustom<pcl::PointWithRange> shadow_points_color_handler (shadow_points_ptr, 0, 255, 255); viewer.addPointCloud<pcl::PointWithRange> (shadow_points_ptr, shadow_points_color_handler, "shadow points"); viewer.setPointCloudRenderingProperties (pcl::visualization::PCL_VISUALIZER_POINT_SIZE, 7, "shadow points"); //------------------------------------- // -----Show points on range image----- // ------------------------------------ pcl::visualization::RangeImageVisualizer* range_image_borders_widget = NULL; range_image_borders_widget = pcl::visualization::RangeImageVisualizer::getRangeImageBordersWidget (range_image, -std::numeric_limits<float>::infinity (), std::numeric_limits<float>::infinity (), false, border_descriptions, "Range image with borders"); // ------------------------------------- //-------------------- // -----Main loop----- //-------------------- while (!viewer.wasStopped ()) { range_image_borders_widget->spinOnce (); viewer.spinOnce (); pcl_sleep(0.01); } }
代码解释
在刚开始,我们做命令行解析,从一个磁盘里面读取点云,我们创造了一个深度图并把它进行可视化。所有的这些步骤在"Range Image Visualization"里面有讲。
这里只有一小点偏差。为了导出边缘信息,我们要区别出无法到的深度点和超出观察范围之外的深度点。接着我们标记一个边框,观察不到的点不用标记。因此提供一些测量参数是很重要的。我们将找到一个额外的pcd文件包含如下的值。
std::string far_ranges_filename = pcl::getFilenameWithoutExtension (filename)+"_far_ranges.pcd"; if (pcl::io::loadPCDFile(far_ranges_filename.c_str(), far_ranges) == -1) std::cout << "Far ranges file \""<<far_ranges_filename<<"\" does not exists.\n";
他们等一下将融入深度图里面
range_image.integrateFarRanges (far_ranges);
如果这些值没有提供,命令行参数-m将被用来赋值,所有不能观测到地点都被认为很远距离的点。
if (setUnseenToMaxRange) range_image.setUnseenToMaxRange ();
接下去我们将来到与边缘导出相关的部分
pcl::RangeImageBorderExtractor border_extractor (&range_image); pcl::PointCloud<pcl::BorderDescription> border_descriptions; border_extractor.compute (border_descriptions);
上面将会创建RangeImageBorderExtractor这个类,给一个深度图,计算边缘信息,并把它存在border_descriptions里面。
最后 ,viewer.addCoordinateSystem (1.0f, "global");可能会出现错误,把代码改成viewer.addCoordinateSystem (1.0f);
直接运行它
/range_image_border_extraction -m
使用一个点云文件
./range_image_border_extraction <point_cloud.pcd>