使用ConditionalRemoval或RadiusOutlinerRemove移除离群点

#include <iostream>
#include <pcl/point_types.h>
#include <pcl/filters/radius_outlier_removal.h>
#include <pcl/filters/conditional_removal.h>

int main(int argc,char ** argv) {
    //确保输入的参数
    if (argc!=2){
        std::cerr<<"please specify command line arg '-r' or '-c'"<<std::endl;
        return 0;
    }
    pcl::PointCloud<pcl::PointXYZ>::Ptr cloud(new pcl::PointCloud<pcl::PointXYZ>);
    pcl::PointCloud<pcl::PointXYZ>::Ptr cloud_filtered(new pcl::PointCloud<pcl::PointXYZ>);

    cloud->width=10;
    cloud->height=1;
    cloud->resize(cloud->height*cloud->width);

    for (size_t i = 0; i < cloud->points.size(); ++i) {
        cloud->points[i].x=1024*rand()/(RAND_MAX+1.0f);
        cloud->points[i].y=1024*rand()/(RAND_MAX+1.0f);
        cloud->points[i].z=1024*rand()/(RAND_MAX+1.0f);
    }

    //strcmp用于比较两个字符串s1和s2。如果s1<s2,返回值<0；如果s1=s2,返回值=0；如果s1>s2,则返回值>0
    if (strcmp(argv[1],"-r")==0){
        //如果输入的是-r，则执行下面的部分
        pcl::RadiusOutlierRemoval<pcl::PointXYZ> outrem;//创建半径外点滤波器
        outrem.setInputCloud(cloud);//设定输入点云
        outrem.setRadiusSearch(0.8);//设定搜索半径
        outrem.setMinNeighborsInRadius(2);//设定半径内的内点阈值，半径内的点如果小于阈值，则会被滤除
        outrem.setKeepOrganized(false);
        outrem.filter(*cloud_filtered);//输出处理结果
    } else if(strcmp(argv[1],"-c")==0){

        pcl::ConditionAnd<pcl::PointXYZ>::Ptr range_cond(new pcl::ConditionAnd<pcl::PointXYZ>);//创建条件定义对象
        //为此条件对象添加比较算子
        range_cond->addComparison(pcl::FieldComparison<pcl::PointXYZ>::ConstPtr (new pcl::FieldComparison<pcl::PointXYZ>("z",pcl::ComparisonOps::GT,0.0)));//添加在z字段上大于0的比较算子
        range_cond->addComparison(pcl::FieldComparison<pcl::PointXYZ>::ConstPtr (new pcl::FieldComparison<pcl::PointXYZ>("z",pcl::ComparisonOps::LT,0.8)));//添加在z字段上小于0.8的比较算子

        pcl::ConditionalRemoval<pcl::PointXYZ> condrem;//创建条件滤波器
        condrem.setInputCloud(cloud);//设定输入点云
        condrem.setCondition(range_cond);//设定条件
        condrem.setKeepOrganized(false);//设定为true则保留点云的结构，否则不保留，默认为false
        condrem.filter(*cloud_filtered);//输出结果
    } else{
        std::cerr<<"Please specify common line arg '-r' or '-c'"<<std::endl;
        return 0;
    }
    std::cerr<<"Cloud before filtering: "<<std::endl;
    for (size_t i = 0; i < cloud->points.size(); ++i) {
        std::cerr<<"   "<<cloud->points[i].x<<" "
                        <<cloud->points[i].y<<" "
                        <<cloud->points[i].z<<" "
                        <<std::endl;
    }
    std::cerr<<"Cloud after filtering: "<<std::endl;
    for (size_t i = 0; i < cloud_filtered->points.size(); ++i) {
        std::cerr<<"   "<<cloud_filtered->points[i].x<<" "
                        <<cloud_filtered->points[i].y<<" "
                        <<cloud_filtered->points[i].z<<" "
                        <<std::endl;
    }
    return 0;
}