Visualize PCD containing custom double point structure - double

Question

I have created a custom double point-type for storing the point position in the PCD file. I required the double data type since my points are in global coordinates and have very large values (of order 10^6 to 10^7) and require good precision. Since the values are large and the default FLOAT32 precision is limited, there is considerable data approximation which is also visible during visualization.
I created this PCD by transforming the raw pointcloud with the initial global reference coordinate from GPS in the data bag that I have. I am using a 15 point precision.
I created a separate script for visualizing this custom point-type PCD. But by visually comparing, I cannot see any considerable difference between the FLOAT32 and double data-type PCD's.
Raw_float_pcd_visualization
Transformed_float_pcd_visualization
Transformed_double_pcd_visualization
You can see that the transformed_double and transformed_float PCD's are quite similar and approximated. While the raw_float PCD is quite good as compared to these two.
I am attaching the PCD files for reference:
raw_float
transformed_float
transformed_double
I think that I am skipping some things while loading the pointcloud and there are some more changes that need to be done in order to visualize the points with double point precision.
I used "pcl_viewer" from pcl_tools for visualizing FLOAT type PCD's.
Code for visualizaing custom DOUBLE point-structure PCD:
#define PCL_NO_PRECOMPILE
#include <iostream>
// #include "double_viz/pcl_double.h"
#include <pcl-1.7/pcl/common/common.h>
#include <pcl-1.7/pcl/io/pcd_io.h>
#include <pcl-1.7/pcl/visualization/pcl_visualizer.h>
#include <pcl-1.7/pcl/console/parse.h>
#include <pcl-1.7/pcl/point_cloud.h>
#include <pcl-1.7/pcl/point_types.h>
namespace pcl
{
#define PCL_ADD_UNION_POINT4D_DOUBLE \
union EIGEN_ALIGN16 { \
double data[4]; \
struct { \
double x; \
double y; \
double z; \
}; \
};
struct _PointXYZDouble
{
PCL_ADD_UNION_POINT4D_DOUBLE; // This adds the members x,y,z which can also be accessed using the point (which is float[4])
EIGEN_MAKE_ALIGNED_OPERATOR_NEW
};
struct EIGEN_ALIGN16 PointXYZDouble : public _PointXYZDouble
{
inline PointXYZDouble (const _PointXYZDouble &p)
{
x = p.x; y = p.y; z = p.z; data[3] = 1.0;
}
inline PointXYZDouble ()
{
x = y = z = 0.0;
data[3] = 1.0;
}
inline PointXYZDouble (double _x, double _y, double _z)
{
x = _x; y = _y; z = _z;
data[3] = 1.0;
}
EIGEN_MAKE_ALIGNED_OPERATOR_NEW
};
}
POINT_CLOUD_REGISTER_POINT_STRUCT (pcl::_PointXYZDouble,
(double, x, x)
(double, y, y)
(double, z, z)
)
POINT_CLOUD_REGISTER_POINT_WRAPPER(pcl::PointXYZDouble, pcl::_PointXYZDouble)
// This function displays the help
void
showHelp(char * program_name)
{
std::cout << std::endl;
std::cout << "Usage: " << program_name << " cloud_filename.[pcd]" << std::endl;
std::cout << "-h: Show this help." << std::endl;
}
// This is the main function
int
main (int argc, char** argv)
{
// Show help
if (pcl::console::find_switch (argc, argv, "-h") || pcl::console::find_switch (argc, argv, "--help"))
{
showHelp (argv[0]);
return 0;
}
// Fetch point cloud filename in arguments | Works with PCD
std::vector<int> filenames;
if (filenames.size () != 1)
{
filenames = pcl::console::parse_file_extension_argument (argc, argv, ".pcd");
if (filenames.size () != 1)
{
showHelp (argv[0]);
return -1;
}
}
// Load file | Works with PCD and PLY files
pcl::PointCloud<pcl::PointXYZDouble>::Ptr source_cloud (new pcl::PointCloud<pcl::PointXYZDouble> ());
if (pcl::io::loadPCDFile (argv[filenames[0]], *source_cloud) < 0)
{
std::cout << "Error loading point cloud " << argv[filenames[0]] << std::endl << std::endl;
showHelp (argv[0]);
return -1;
}
// Visualization
// printf( "\nPoint cloud colors : white = original point cloud\n"
// " red = transformed point cloud\n");
pcl::visualization::PCLVisualizer viewer ("Visualize double PCL");
// Define R,G,B colors for the point cloud
pcl::visualization::PointCloudColorHandlerCustom<pcl::PointXYZDouble> source_cloud_color_handler (source_cloud, 100, 100, 100);
// We add the point cloud to the viewer and pass the color handler
viewer.addPointCloud (source_cloud, source_cloud_color_handler, "original_cloud");
viewer.addCoordinateSystem (1.0, "cloud", 0);
viewer.setBackgroundColor(0.05, 0.05, 0.05, 0); // Setting background to a dark grey
viewer.setPointCloudRenderingProperties (pcl::visualization::PCL_VISUALIZER_OPACITY, 1, "original_cloud");
viewer.setPointCloudRenderingProperties (pcl::visualization::PCL_VISUALIZER_POINT_SIZE, 1, "original_cloud");
viewer.setPointCloudRenderingProperties (pcl::visualization::PCL_VISUALIZER_LINE_WIDTH, 1, "original_cloud");
//viewer.setPosition(800, 400); // Setting visualiser window position
while (!viewer.wasStopped ()) // Display the visualiser until 'q' key is pressed
{
viewer.spinOnce ();
}
return 0;
}

Answer 1

In the raw_float file, the size field has been defined as 4 bytes each: SIZE 4 4 4 4,
to be read as double it should be SIZE 8 8 8 8.
With your current implementation each field is being read as Float32