PCL学习（三） SAC-IA 估记object pose

SAC-IA是基于RANSAC算法的对齐算法

通过降采样提高法向计算、FPFH特征的计算

最后通过SAC-IA计算得到对齐的旋转和平移

#include <Eigen/Core>
#include <pcl/point_types.h>
#include <pcl/point_cloud.h>
#include <pcl/common/time.h>
#include <pcl/console/print.h>
#include <pcl/features/normal_3d_omp.h>
#include <pcl/features/fpfh_omp.h>
#include <pcl/filters/filter.h>
#include <pcl/filters/voxel_grid.h>
#include <pcl/io/pcd_io.h>
#include <pcl/registration/icp.h>
#include <pcl/registration/sample_consensus_prerejective.h>
#include <pcl/segmentation/sac_segmentation.h>
#include <pcl/visualization/pcl_visualizer.h>
#include <string>
#include <iostream>
#include <stdio.h>
#include <stdlib.h>
// Types
typedef pcl::PointNormal PointNT;
typedef pcl::PointCloud<PointNT> PointCloudT;
typedef pcl::FPFHSignature33 FeatureT;
typedef pcl::FPFHEstimationOMP<PointNT, PointNT, FeatureT> FeatureEstimationT;
typedef pcl::PointCloud<FeatureT> FeatureCloudT;
typedef pcl::visualization::PointCloudColorHandlerCustom<PointNT> ColorHandlerT;

//handle the param of the align in the txt to save the fucking time of complie
int parseConfigFile(
	const std::string &filepath,
	char *objFile,
	char *sceFile,
	float *downLeaf
);


// Align a rigid object to a scene with clutter and occlusions
int main(int argc, char **argv)
{
	// Point clouds
	PointCloudT::Ptr object(new PointCloudT);
	PointCloudT::Ptr object_aligned(new PointCloudT);
	PointCloudT::Ptr scene(new PointCloudT);
	FeatureCloudT::Ptr object_features(new FeatureCloudT);
	FeatureCloudT::Ptr scene_features(new FeatureCloudT);

	// Get input object and scene
	/*if (argc != 3)
	{
	pcl::console::print_error("Syntax is: %s object.pcd scene.pcd
", argv[0]);
	return (1);
	}*/
	/*std::string paramFilePath = "data/param.txt";
	char *obj_filepath = { '' };
	char *sce_filepath = { '' };
	float *downsample_leaf = nullptr;
	parseConfigFile(
	paramFilePath,
	obj_filepath,
	sce_filepath,
	downsample_leaf
	);*/


	// Load object and scene
	pcl::console::print_highlight("Loading point clouds...
");
	if (pcl::io::loadPCDFile<PointNT>("data/obj_seg.pcd", *object) < 0 ||//"data/obj_seg.pcd"
		pcl::io::loadPCDFile<PointNT>("data/sce_seg.pcd", *scene) < 0)   //"data/sce_seg.pcd"
	{
		pcl::console::print_error("Error loading object/scene file!
");
		return (1);
	}

	// Downsample
	pcl::console::print_highlight("Downsampling...
");
	pcl::VoxelGrid<PointNT> grid;
	const float leaf = 0.08f;//0.005f == resolution of 5mm
	grid.setLeafSize(leaf, leaf, leaf);
	grid.setInputCloud(object);
	grid.filter(*object);
	grid.setInputCloud(scene);
	grid.filter(*scene);

	// Estimate normals for scene
	pcl::console::print_highlight("Estimating scene normals...
");
	pcl::NormalEstimationOMP<PointNT, PointNT> nest;
	nest.setRadiusSearch(0.01);
	nest.setInputCloud(scene);
	nest.compute(*scene);

	// Estimate features
	pcl::console::print_highlight("Estimating features...
");
	FeatureEstimationT fest;
	fest.setRadiusSearch(0.025);
	fest.setInputCloud(object);
	fest.setInputNormals(object);
	fest.compute(*object_features);
	fest.setInputCloud(scene);
	fest.setInputNormals(scene);
	fest.compute(*scene_features);

	// Perform alignment
	pcl::console::print_highlight("Starting alignment...
");
	pcl::SampleConsensusPrerejective<PointNT, PointNT, FeatureT> align;
	align.setInputSource(object);
	align.setSourceFeatures(object_features);
	align.setInputTarget(scene);
	align.setTargetFeatures(scene_features);
	align.setMaximumIterations(100000); // Number of RANSAC iterations 50000
	align.setNumberOfSamples(3); // Number of points to sample for generating/prerejecting a pose
	align.setCorrespondenceRandomness(5); // Number of nearest features to use
	align.setSimilarityThreshold(0.9f); // Polygonal edge length similarity threshold
	align.setMaxCorrespondenceDistance(2.5f * leaf); // Inlier threshold
	align.setInlierFraction(0.25f); // Required inlier fraction for accepting a pose hypothesis
	{
		pcl::ScopeTime t("Alignment");
		align.align(*object_aligned);
	}

	if (align.hasConverged())
	{
		// Print results
		printf("
");
		Eigen::Matrix4f transformation = align.getFinalTransformation();
		pcl::console::print_info("    | %6.3f %6.3f %6.3f | 
", transformation(0, 0), transformation(0, 1), transformation(0, 2));
		pcl::console::print_info("R = | %6.3f %6.3f %6.3f | 
", transformation(1, 0), transformation(1, 1), transformation(1, 2));
		pcl::console::print_info("    | %6.3f %6.3f %6.3f | 
", transformation(2, 0), transformation(2, 1), transformation(2, 2));
		pcl::console::print_info("
");
		pcl::console::print_info("t = < %0.3f, %0.3f, %0.3f >
", transformation(0, 3), transformation(1, 3), transformation(2, 3));
		pcl::console::print_info("
");
		pcl::console::print_info("Inliers: %i/%i
", align.getInliers().size(), object->size());

		// Show alignment
		pcl::visualization::PCLVisualizer visu("Alignment");
		visu.addPointCloud(scene, ColorHandlerT(scene, 0.0, 255.0, 0.0), "scene");
		visu.addPointCloud(object_aligned, ColorHandlerT(object_aligned, 0.0, 0.0, 255.0), "object_aligned");
		visu.spin();
		system("PAUSE");
	}
	else
	{
		pcl::console::print_error("Alignment failed!
");
		system("PAUSE");
		return (1);
	}

	return (0);
}

int parseConfigFile(
	const std::string &filepath,
	char *objFile,
	char *sceFile,
	float *downLeaf
)
{
	// open the configuration file
	FILE *file = fopen(filepath.c_str(), "r");
	//FILE *stream;//test
	if (!file)
	{
		fprintf(stderr, "Cannot parse configuration file "%s".
",
			filepath.c_str());
		exit(1);
	}
	//read parameters
	char buf[256];
	while (fscanf(file, "%s", buf) != EOF) {
		switch (buf[0]) {
		case '#':
			fgets(buf, sizeof(buf), file);
			break;
		case'o':
			fgets(buf, sizeof(buf), file);
			memcpy(objFile, buf + 1, strlen(buf) - 2);
			//printf("%s", objFile);
			break;
		case's':
			fgets(buf, sizeof(buf), file);
			memcpy(sceFile, buf + 1, strlen(buf) - 2);
			break;
		case'l':
			fscanf(file, "%f", downLeaf);
		}
	}
	return 0;

}　

　

对齐前的点云数据（采集于两帧kinect的扫描深度图）

对齐后的结果

对齐的旋转和平移，以及对齐速度