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#include "utility.h"
#include "lio_sam/cloud_info.h"
struct smoothness_t{
float value;
size_t ind;
};
struct by_value{
bool operator()(smoothness_t const &left, smoothness_t const &right) {
return left.value < right.value;
}
};
class FeatureExtraction : public ParamServer
{
public:
ros::Subscriber subLaserCloudInfo;
ros::Publisher pubLaserCloudInfo;
ros::Publisher pubCornerPoints;
ros::Publisher pubSurfacePoints;
pcl::PointCloud<PointType>::Ptr extractedCloud;
pcl::PointCloud<PointType>::Ptr cornerCloud;
pcl::PointCloud<PointType>::Ptr surfaceCloud;
lio_sam::cloud_info cloudInfo;
std_msgs::Header cloudHeader;
std::vector<smoothness_t> cloudSmoothness;
float *cloudCurvature;
int *cloudNeighborPicked;
int *cloudLabel;
FeatureExtraction()
{
subLaserCloudInfo = nh.subscribe<lio_sam::cloud_info>("lio_sam/deskew/cloud_info", 1, &FeatureExtraction::laserCloudInfoHandler, this, ros::TransportHints().tcpNoDelay());
pubLaserCloudInfo = nh.advertise<lio_sam::cloud_info> ("lio_sam/feature/cloud_info", 1);
pubCornerPoints = nh.advertise<sensor_msgs::PointCloud2>("lio_sam/feature/cloud_corner", 1);
pubSurfacePoints = nh.advertise<sensor_msgs::PointCloud2>("lio_sam/feature/cloud_surface", 1);
initializationValue();
}
void initializationValue()
{
cloudSmoothness.resize(N_SCAN*Horizon_SCAN);
downSizeFilter.setLeafSize(odometrySurfLeafSize, odometrySurfLeafSize, odometrySurfLeafSize);
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extractedCloud.reset(new pcl::PointCloud<PointType>());
cornerCloud.reset(new pcl::PointCloud<PointType>());
surfaceCloud.reset(new pcl::PointCloud<PointType>());
cloudCurvature = new float[N_SCAN*Horizon_SCAN];
cloudNeighborPicked = new int[N_SCAN*Horizon_SCAN];
cloudLabel = new int[N_SCAN*Horizon_SCAN];
}
void laserCloudInfoHandler(const lio_sam::cloud_infoConstPtr& msgIn)
{
cloudInfo = *msgIn; // new cloud info
cloudHeader = msgIn->header; // new cloud header
pcl::fromROSMsg(msgIn->cloud_deskewed, *extractedCloud); // new cloud for extraction
calculateSmoothness();
markOccludedPoints();
extractFeatures();
publishFeatureCloud();
}
void calculateSmoothness()
{
int cloudSize = extractedCloud->points.size();
for (int i = 5; i < cloudSize - 5; i++)
{
float diffRange = cloudInfo.pointRange[i-5] + cloudInfo.pointRange[i-4]
+ cloudInfo.pointRange[i-3] + cloudInfo.pointRange[i-2]
+ cloudInfo.pointRange[i-1] - cloudInfo.pointRange[i] * 10
+ cloudInfo.pointRange[i+1] + cloudInfo.pointRange[i+2]
+ cloudInfo.pointRange[i+3] + cloudInfo.pointRange[i+4]
+ cloudInfo.pointRange[i+5];
cloudCurvature[i] = diffRange*diffRange;//diffX * diffX + diffY * diffY + diffZ * diffZ;
cloudNeighborPicked[i] = 0;
cloudLabel[i] = 0;
// cloudSmoothness for sorting
cloudSmoothness[i].value = cloudCurvature[i];
cloudSmoothness[i].ind = i;
}
}
void markOccludedPoints()
{
int cloudSize = extractedCloud->points.size();
// mark occluded points and parallel beam points
for (int i = 5; i < cloudSize - 6; ++i)
{
// occluded points
float depth1 = cloudInfo.pointRange[i];
float depth2 = cloudInfo.pointRange[i+1];
int columnDiff = std::abs(int(cloudInfo.pointColInd[i+1] - cloudInfo.pointColInd[i]));
if (columnDiff < 10){
// 10 pixel diff in range image
if (depth1 - depth2 > 0.3){
cloudNeighborPicked[i - 5] = 1;
cloudNeighborPicked[i - 4] = 1;
cloudNeighborPicked[i - 3] = 1;
cloudNeighborPicked[i - 2] = 1;
cloudNeighborPicked[i - 1] = 1;
cloudNeighborPicked[i] = 1;
}else if (depth2 - depth1 > 0.3){
cloudNeighborPicked[i + 1] = 1;
cloudNeighborPicked[i + 2] = 1;
cloudNeighborPicked[i + 3] = 1;
cloudNeighborPicked[i + 4] = 1;
cloudNeighborPicked[i + 5] = 1;
cloudNeighborPicked[i + 6] = 1;
}
}
// parallel beam
float diff1 = std::abs(float(cloudInfo.pointRange[i-1] - cloudInfo.pointRange[i]));
float diff2 = std::abs(float(cloudInfo.pointRange[i+1] - cloudInfo.pointRange[i]));
if (diff1 > 0.02 * cloudInfo.pointRange[i] && diff2 > 0.02 * cloudInfo.pointRange[i])
cloudNeighborPicked[i] = 1;
}
}
void extractFeatures()
{
cornerCloud->clear();
surfaceCloud->clear();
pcl::PointCloud<PointType>::Ptr surfaceCloudScan(new pcl::PointCloud<PointType>());
pcl::PointCloud<PointType>::Ptr surfaceCloudScanDS(new pcl::PointCloud<PointType>());
for (int i = 0; i < N_SCAN; i++)
{
surfaceCloudScan->clear();
for (int j = 0; j < 6; j++)
{
int sp = (cloudInfo.startRingIndex[i] * (6 - j) + cloudInfo.endRingIndex[i] * j) / 6;
int ep = (cloudInfo.startRingIndex[i] * (5 - j) + cloudInfo.endRingIndex[i] * (j + 1)) / 6 - 1;
if (sp >= ep)
continue;
std::sort(cloudSmoothness.begin()+sp, cloudSmoothness.begin()+ep, by_value());
int largestPickedNum = 0;
for (int k = ep; k >= sp; k--)
{
int ind = cloudSmoothness[k].ind;
if (cloudNeighborPicked[ind] == 0 && cloudCurvature[ind] > edgeThreshold)
{
largestPickedNum++;
if (largestPickedNum <= 20){
cloudLabel[ind] = 1;
cornerCloud->push_back(extractedCloud->points[ind]);
} else {
break;
}
cloudNeighborPicked[ind] = 1;
for (int l = 1; l <= 5; l++)
{
int columnDiff = std::abs(int(cloudInfo.pointColInd[ind + l] - cloudInfo.pointColInd[ind + l - 1]));
if (columnDiff > 10)
break;
cloudNeighborPicked[ind + l] = 1;
}
for (int l = -1; l >= -5; l--)
{
int columnDiff = std::abs(int(cloudInfo.pointColInd[ind + l] - cloudInfo.pointColInd[ind + l + 1]));
if (columnDiff > 10)
break;
cloudNeighborPicked[ind + l] = 1;
}
}
}
for (int k = sp; k <= ep; k++)
{
int ind = cloudSmoothness[k].ind;
if (cloudNeighborPicked[ind] == 0 && cloudCurvature[ind] < surfThreshold)
{
cloudLabel[ind] = -1;
cloudNeighborPicked[ind] = 1;
for (int l = 1; l <= 5; l++) {
int columnDiff = std::abs(int(cloudInfo.pointColInd[ind + l] - cloudInfo.pointColInd[ind + l - 1]));
if (columnDiff > 10)
break;
cloudNeighborPicked[ind + l] = 1;
}
for (int l = -1; l >= -5; l--) {
int columnDiff = std::abs(int(cloudInfo.pointColInd[ind + l] - cloudInfo.pointColInd[ind + l + 1]));
if (columnDiff > 10)
break;
cloudNeighborPicked[ind + l] = 1;
}
}
}
for (int k = sp; k <= ep; k++)
{
if (cloudLabel[k] <= 0){
surfaceCloudScan->push_back(extractedCloud->points[k]);
}
}
}
surfaceCloudScanDS->clear();
downSizeFilter.setInputCloud(surfaceCloudScan);
downSizeFilter.filter(*surfaceCloudScanDS);
*surfaceCloud += *surfaceCloudScanDS;
}
}
void freeCloudInfoMemory()
{
cloudInfo.startRingIndex.clear();
cloudInfo.endRingIndex.clear();
cloudInfo.pointColInd.clear();
cloudInfo.pointRange.clear();
}
void publishFeatureCloud()
{
// free cloud info memory
freeCloudInfoMemory();
// save newly extracted features
cloudInfo.cloud_corner = publishCloud(pubCornerPoints, cornerCloud, cloudHeader.stamp, lidarFrame);
cloudInfo.cloud_surface = publishCloud(pubSurfacePoints, surfaceCloud, cloudHeader.stamp, lidarFrame);
// publish to mapOptimization
pubLaserCloudInfo.publish(cloudInfo);
}
};
int main(int argc, char** argv)
{
ros::init(argc, argv, "lio_sam");
FeatureExtraction FE;
ROS_INFO("\033[1;32m----> Feature Extraction Started.\033[0m");
ros::spin();
return 0;
}