cartographer源码分析(35)-io-fixed_ratio_sampling_points_processor.h

源码可在https://github.com/learnmoreonce/SLAM 下载

文件:fixed_ratio_sampling_points_processor.h#ifndef CARTOGRAPHER_IO_FIXED_RATIO_SAMPLING_POINTS_PROCESSOR_H_#define CARTOGRAPHER_IO_FIXED_RATIO_SAMPLING_POINTS_PROCESSOR_H_#include <memory>#include "cartographer/common/fixed_ratio_sampler.h"#include "cartographer/common/lua_parameter_dictionary.h"#include "cartographer/io/points_processor.h"namespace cartographer {namespace io {/*FixedRatioSamplingPointsProcessor是PointsProcessor的第七个子类(7).FixedRatioSamplingPointsProcessor是采样过滤器,该class只让具有固定采样频率的点通过,其余全部 remove.sampling_ratio=1,即无任何操作,全通滤波.sparse_pose_graph.lua: sampling_ratio = 0.3,*/// Only let a fixed 'sampling_ratio' of points through. A 'sampling_ratio' of 1.// makes this filter a no-op.class FixedRatioSamplingPointsProcessor : public PointsProcessor { public:  constexpr static const char* kConfigurationFileActionName =      "fixed_ratio_sampler";  FixedRatioSamplingPointsProcessor(double sampling_ratio,                                    PointsProcessor* next);  static std::unique_ptr<FixedRatioSamplingPointsProcessor> FromDictionary(      common::LuaParameterDictionary* dictionary, PointsProcessor* next);  ~FixedRatioSamplingPointsProcessor() override{};  FixedRatioSamplingPointsProcessor(const FixedRatioSamplingPointsProcessor&) =      delete;  FixedRatioSamplingPointsProcessor& operator=(      const FixedRatioSamplingPointsProcessor&) = delete;//根据采样率采集点云，不在采样点上的全部删除。  void Process(std::unique_ptr<PointsBatch> batch) override;  FlushResult Flush() override; private:  const double sampling_ratio_;//采样率  PointsProcessor* const next_;  std::unique_ptr<common::FixedRatioSampler> sampler_;//具有固定采样率的采样函数};}  // namespace io}  // namespace cartographer#endif  // CARTOGRAPHER_IO_FIXED_RATIO_SAMPLING_POINTS_PROCESSOR_H_

fixed_ratio_sampling_points_processor.cc#include "cartographer/io/fixed_ratio_sampling_points_processor.h"#include "Eigen/Core"#include "cartographer/common/make_unique.h"#include "glog/logging.h"namespace cartographer {namespace io {/*静态成员函数,利用参数构造一个智能指针指向FixedRatioSamplingPointsProcessor的对象*/std::unique_ptr<FixedRatioSamplingPointsProcessor>FixedRatioSamplingPointsProcessor::FromDictionary(    common::LuaParameterDictionary* const dictionary,    PointsProcessor* const next) {  const double sampling_ratio(dictionary->GetDouble("sampling_ratio"));   //sparse_pose_graph.lua:0.3,0.03  CHECK_LT(0., sampling_ratio) << "Sampling ratio <= 0 makes no sense.";  CHECK_LT(sampling_ratio, 1.) << "Sampling ratio >= 1 makes no sense.";  return common::make_unique<FixedRatioSamplingPointsProcessor>(sampling_ratio,                                                                next);}/*构造函数用采样率 sampling_ratio和PointsProcessor* next初始化*/FixedRatioSamplingPointsProcessor::FixedRatioSamplingPointsProcessor(    const double sampling_ratio, PointsProcessor* next)    : sampling_ratio_(sampling_ratio),      next_(next),      sampler_(new common::FixedRatioSampler(sampling_ratio_)) {}/*该类的核心函数,有几个为了提高效率的地方:Process()传递智能指针,指向堆上的点集PointsBatch,理论上该点集组成的vector是不断增加的.但是同时也有其他Process()在删除PointsBatch*/void FixedRatioSamplingPointsProcessor::Process(    std::unique_ptr<PointsBatch> batch) {  std::vector<int> to_remove;                         //保存索引  for (size_t i = 0; i < batch->points.size(); ++i) { //points是vector    if (!sampler_->Pulse()) {  //调用一次Pulse()其实影响到了sampler_的内部状态.//模拟的传感器sampler_没有产生一个脉冲,则说明当前的batch[i]应该删除.      to_remove.push_back(i);    }  }  RemovePoints(to_remove, batch.get());  next_->Process(std::move(batch));//虚函数,调用子类的Process(),也就是这个函数本身}PointsProcessor::FlushResult FixedRatioSamplingPointsProcessor::Flush() {  switch (next_->Flush()) {    case PointsProcessor::FlushResult::kFinished:     //下一步已经完成,析构时则这一步也标记完成      return PointsProcessor::FlushResult::kFinished;    case PointsProcessor::FlushResult::kRestartStream://重启采样    //为何要重新赋值?:重启,不能带有以前的状态,所以重新初始化.      sampler_ =          common::make_unique<common::FixedRatioSampler>(sampling_ratio_);      return PointsProcessor::FlushResult::kRestartStream;  }  LOG(FATAL);}}  // namespace io}  // namespace cartographer

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* https://zhuanlan.zhihu.com/learnmoreonce
* http://blog.csdn.net/learnmoreonce
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