Carto更新

  // Applies the 'odds' specified when calling ComputeLookupTableToApplyOdds()
  // to the probability of the cell at 'xy_index' if the cell has not already
  // been updated. Multiple updates of the same cell will be ignored until
  // StartUpdate() is called. Returns true if the cell was updated.
  //
  // If this is the first call to ApplyOdds() for the specified cell, its value
  // will be set to probability corresponding to 'odds'.

这里就是log odds 表示 ，如果没被更新过 则更新， 多次更新相同的cell会被忽略 。如果

  bool ApplyLookupTable(const Eigen::Array2i& xy_index,
                        const std::vector<uint16>& table) {
    DCHECK_EQ(table.size(), mapping::kUpdateMarker);
    const int cell_index = GetIndexOfCell(xy_index);
    uint16& cell = cells_[cell_index];
    if (cell >= mapping::kUpdateMarker) {
      return false;
    }
    update_indices_.push_back(cell_index);
    cell = table[cell];
    DCHECK_GE(cell, mapping::kUpdateMarker);
    UpdateBounds(xy_index);
    return true;
  }

/////////////////////// xlimit * y +x 等于格子数

    int GetIndexofCell(const Eigen::Array2i & xy_index)
    {
        return (maplimits_.Getcelllimits().num_x_cells*xy_index.y()+xy_index.x() );
    }

/////////////////////////////////////////sensor data ////////////////////

这里是谷歌最难得一步

////////////////////////////////

add sensor data 有trajectory builder 的 

真正实现是一个collator  然后有下面的

 private:
  // Queue keys are a pair of trajectory ID and sensor identifier.
  OrderedMultiQueue queue_;