文章目录
- 0 前情回顾
-
- 1 updateLatestStates() 和slideWindow()
- 2 optimization()
0 前情回顾
VINS-FUSION代码超详细注释(VIO部分)/VIO入门(1)讲到了主程序rosNodeTest.cpp。在程序最后,会进入sync_process线程进行处理。本篇博客接着进行讲解。
VINS-FUSION代码超详细注释(VIO部分)/VIO入门(2)中,讲了sync_process
,以及其中的trackImage
和processMeasurements
,包括processMeasurements
中对IMU数据的处理部分.
VINS-FUSION代码超详细注释(VIO部分)/VIO入门(3)中,讲了processImage
,其中就包含了初始化,三角化,非线性优化,划窗等等内容.
本文主要对函数optimization() updateLatestStates() slideWindow()
进行介绍.
本次工作
我首先一步步的把代码全部注释了,十分的详细,对于C++和OpenCV的一些操作也进行了详细的注释,对于刚入门的同学应该还是有帮助的。之后我将代码开源,并写了相应的博客进行讲解。
开源程序:
https://github.com/kuankuan-yue/VINS-FUSION-leanrning.git
相应博客:
VINS-FUSION代码超详细注释(VIO部分)/VIO入门(1)
VINS-FUSION代码超详细注释(VIO部分)/VIO入门(2)
VINS-FUSION代码超详细注释(VIO部分)/VIO入门(3)
VINS-FUSION代码超详细注释(VIO部分)/VIO入门(4)
1 updateLatestStates() 和slideWindow()
这两个函数比较简单
void Estimator::updateLatestStates()
void Estimator::slideWindow()
2 optimization()
这个函数可以说是整个VIO的精华和难点所在!
因为内容太多了,所以直接贴了代码.对于其中某些函数,如果大家有什么问题的话,可以去github上参考我的代码.
void Estimator::optimization()
{
TicToc t_whole, t_prepare;
vector2double();
ceres::Problem problem;
ceres::LossFunction *loss_function;
loss_function = new ceres::HuberLoss(1.0);
for (int i = 0; i < frame_count + 1; i++)
{
ceres::LocalParameterization *local_parameterization = new PoseLocalParameterization();
problem.AddParameterBlock(para_Pose[i], SIZE_POSE, local_parameterization);
if(USE_IMU)
problem.AddParameterBlock(para_SpeedBias[i], SIZE_SPEEDBIAS);
}
if(!USE_IMU)
problem.SetParameterBlockConstant(para_Pose[0]);
for (int i = 0; i < NUM_OF_CAM; i++)
{
ceres::LocalParameterization *local_parameterization = new PoseLocalParameterization();
problem.AddParameterBlock(para_Ex_Pose[i], SIZE_POSE, local_parameterization);
if ((ESTIMATE_EXTRINSIC && frame_count == WINDOW_SIZE && Vs[0].norm() > 0.2) || openExEstimation)
{
openExEstimation = 1;
}
else
{
problem.SetParameterBlockConstant(para_Ex_Pose[i]);
}
}
problem.AddParameterBlock(para_Td[0], 1);
if (!ESTIMATE_TD || Vs[0].norm() < 0.2)
problem.SetParameterBlockConstant(para_Td[0]);
if (last_marginalization_info && last_marginalization_info->valid)
{
MarginalizationFactor *marginalization_factor = new MarginalizationFactor(last_marginalization_info);
problem.AddResidualBlock(marginalization_factor, NULL,
last_marginalization_parameter_blocks);
}
if(USE_IMU)
{
for (int i = 0; i < frame_count; i++)
{
int j = i + 1;
if (pre_integrations[j]->sum_dt > 10.0)
continue;
IMUFactor* imu_factor = new IMUFactor(pre_integrations[j]);
problem.AddResidualBlock(imu_factor, NULL, para_Pose[i], para_SpeedBias[i], para_Pose[j], para_SpeedBias[j]);
}
}
int f_m_cnt = 0;
int feature_index = -1;
for (auto &it_per_id : f_manager.feature)
{
it_per_id.used_num = it_per_id.feature_per_frame.size();
if (it_per_id.used_num < 4)
continue;
++feature_index;
int imu_i = it_per_id.start_frame, imu_j = imu_i - 1;
Vector3d pts_i = it_per_id.feature_per_frame[0].point;
for (auto &it_per_frame : it_per_id.feature_per_frame)
{
imu_j++;
if (imu_i != imu_j)
{
Vector3d pts_j = it_per_frame.point;
ProjectionTwoFrameOneCamFactor *f_td = new ProjectionTwoFrameOneCamFactor(pts_i, pts_j, it_per_id.feature_per_frame[0].velocity, it_per_frame.velocity,
it_per_id.feature_per_frame[0].cur_td, it_per_frame.cur_td);
problem.AddResidualBlock(f_td, loss_function, para_Pose[imu_i], para_Pose[imu_j], para_Ex_Pose[0], para_Feature[feature_index], para_Td[0]);
}
if(STEREO && it_per_frame.is_stereo)
{
Vector3d pts_j_right = it_per_frame.pointRight;
if(imu_i != imu_j)
{
ProjectionTwoFrameTwoCamFactor *f = new ProjectionTwoFrameTwoCamFactor(pts_i, pts_j_right, it_per_id.feature_per_frame[0].velocity, it_per_frame.velocityRight,
it_per_id.feature_per_frame[0].cur_td, it_per_frame.cur_td);
problem.AddResidualBlock(f, loss_function, para_Pose[imu_i], para_Pose[imu_j], para_Ex_Pose[0], para_Ex_Pose[1], para_Feature[feature_index], para_Td[0]);
}
else
{
ProjectionOneFrameTwoCamFactor *f = new ProjectionOneFrameTwoCamFactor(pts_i, pts_j_right, it_per_id.feature_per_frame[0].velocity, it_per_frame.velocityRight,
it_per_id.feature_per_frame[0].cur_td, it_per_frame.cur_td);
problem.AddResidualBlock(f, loss_function, para_Ex_Pose[0], para_Ex_Pose[1], para_Feature[feature_index], para_Td[0]);
}
}
f_m_cnt++;
}
}
ROS_DEBUG("visual measurement count: %d", f_m_cnt);
ceres::Solver::Options options;
options.linear_solver_type = ceres::DENSE_SCHUR;
options.trust_region_strategy_type = ceres::DOGLEG;
options.max_num_iterations = NUM_ITERATIONS;
if (marginalization_flag == MARGIN_OLD)
options.max_solver_time_in_seconds = SOLVER_TIME * 4.0 / 5.0;
else
options.max_solver_time_in_seconds = SOLVER_TIME;
TicToc t_solver;
ceres::Solver::Summary summary;
ceres::Solve(options, &problem, &summary);
ROS_DEBUG("Iterations : %d", static_cast<int>(summary.iterations.size()));
double2vector();
if(frame_count < WINDOW_SIZE)
return;
TicToc t_whole_marginalization;
if (marginalization_flag == MARGIN_OLD)
{
MarginalizationInfo *marginalization_info = new MarginalizationInfo();
vector2double();
if (last_marginalization_info && last_marginalization_info->valid)
{
vector<int> drop_set;
for (int i = 0; i < static_cast<int>(last_marginalization_parameter_blocks.size()); i++)
{
if (last_marginalization_parameter_blocks[i] == para_Pose[0] ||
last_marginalization_parameter_blocks[i] == para_SpeedBias[0])
drop_set.push_back(i);
}
MarginalizationFactor *marginalization_factor = new MarginalizationFactor(last_marginalization_info);
ResidualBlockInfo *residual_block_info = new ResidualBlockInfo(marginalization_factor, NULL,
last_marginalization_parameter_blocks,
drop_set);
marginalization_info->addResidualBlockInfo(residual_block_info);
}
if(USE_IMU)
{
if (pre_integrations[1]->sum_dt < 10.0)
{
IMUFactor* imu_factor = new IMUFactor(pre_integrations[1]);
ResidualBlockInfo *residual_block_info = new ResidualBlockInfo(imu_factor, NULL,
vector<double *>{para_Pose[0], para_SpeedBias[0], para_Pose[1], para_SpeedBias[1]},
vector<int>{0, 1});
marginalization_info->addResidualBlockInfo(residual_block_info);
}
}
{
int feature_index = -1;
for (auto &it_per_id : f_manager.feature)
{
it_per_id.used_num = it_per_id.feature_per_frame.size();
if (it_per_id.used_num < 4)
continue;
++feature_index;
int imu_i = it_per_id.start_frame, imu_j = imu_i - 1;
if (imu_i != 0)
continue;
Vector3d pts_i = it_per_id.feature_per_frame[0].point;
for (auto &it_per_frame : it_per_id.feature_per_frame)
{
imu_j++;
if(imu_i != imu_j)
{
Vector3d pts_j = it_per_frame.point;
ProjectionTwoFrameOneCamFactor *f_td = new ProjectionTwoFrameOneCamFactor(pts_i, pts_j, it_per_id.feature_per_frame[0].velocity, it_per_frame.velocity,
it_per_id.feature_per_frame[0].cur_td, it_per_frame.cur_td);
ResidualBlockInfo *residual_block_info = new ResidualBlockInfo(f_td, loss_function,
vector<double *>{para_Pose[imu_i], para_Pose[imu_j], para_Ex_Pose[0], para_Feature[feature_index], para_Td[0]},
vector<int>{0, 3});
marginalization_info->addResidualBlockInfo(residual_block_info);
}
if(STEREO && it_per_frame.is_stereo)
{
Vector3d pts_j_right = it_per_frame.pointRight;
if(imu_i != imu_j)
{
ProjectionTwoFrameTwoCamFactor *f = new ProjectionTwoFrameTwoCamFactor(pts_i, pts_j_right, it_per_id.feature_per_frame[0].velocity, it_per_frame.velocityRight,
it_per_id.feature_per_frame[0].cur_td, it_per_frame.cur_td);
ResidualBlockInfo *residual_block_info = new ResidualBlockInfo(f, loss_function,
vector<double *>{para_Pose[imu_i], para_Pose[imu_j], para_Ex_Pose[0], para_Ex_Pose[1], para_Feature[feature_index], para_Td[0]},
vector<int>{0, 4});
marginalization_info->addResidualBlockInfo(residual_block_info);
}
else
{
ProjectionOneFrameTwoCamFactor *f = new ProjectionOneFrameTwoCamFactor(pts_i, pts_j_right, it_per_id.feature_per_frame[0].velocity, it_per_frame.velocityRight,
it_per_id.feature_per_frame[0].cur_td, it_per_frame.cur_td);
ResidualBlockInfo *residual_block_info = new ResidualBlockInfo(f, loss_function,
vector<double *>{para_Ex_Pose[0], para_Ex_Pose[1], para_Feature[feature_index], para_Td[0]},
vector<int>{2});
marginalization_info->addResidualBlockInfo(residual_block_info);
}
}
}
}
}
TicToc t_pre_margin;
marginalization_info->preMarginalize();
ROS_DEBUG("pre marginalization %f ms", t_pre_margin.toc());
TicToc t_margin;
marginalization_info->marginalize();
ROS_DEBUG("marginalization %f ms", t_margin.toc());
std::unordered_map<long, double *> addr_shift;
for (int i = 1; i <= WINDOW_SIZE; i++)
{
addr_shift[reinterpret_cast<long>(para_Pose[i])] = para_Pose[i - 1];
if(USE_IMU)
addr_shift[reinterpret_cast<long>(para_SpeedBias[i])] = para_SpeedBias[i - 1];
}
for (int i = 0; i < NUM_OF_CAM; i++)
addr_shift[reinterpret_cast<long>(para_Ex_Pose[i])] = para_Ex_Pose[i];
addr_shift[reinterpret_cast<long>(para_Td[0])] = para_Td[0];
vector<double *> parameter_blocks = marginalization_info->getParameterBlocks(addr_shift);
if (last_marginalization_info)
delete last_marginalization_info;
last_marginalization_info = marginalization_info;
last_marginalization_parameter_blocks = parameter_blocks;
}
else
{
if (last_marginalization_info &&
std::count(std::begin(last_marginalization_parameter_blocks), std::end(last_marginalization_parameter_blocks), para_Pose[WINDOW_SIZE - 1]))
{
MarginalizationInfo *marginalization_info = new MarginalizationInfo();
vector2double();
if (last_marginalization_info && last_marginalization_info->valid)
{
vector<int> drop_set;
for (int i = 0; i < static_cast<int>(last_marginalization_parameter_blocks.size()); i++)
{
ROS_ASSERT(last_marginalization_parameter_blocks[i] != para_SpeedBias[WINDOW_SIZE - 1]);
if (last_marginalization_parameter_blocks[i] == para_Pose[WINDOW_SIZE - 1])
drop_set.push_back(i);
}
MarginalizationFactor *marginalization_factor = new MarginalizationFactor(last_marginalization_info);
ResidualBlockInfo *residual_block_info = new ResidualBlockInfo(marginalization_factor, NULL,
last_marginalization_parameter_blocks,
drop_set);
marginalization_info->addResidualBlockInfo(residual_block_info);
}
TicToc t_pre_margin;
ROS_DEBUG("begin marginalization");
marginalization_info->preMarginalize();
ROS_DEBUG("end pre marginalization, %f ms", t_pre_margin.toc());
TicToc t_margin;
ROS_DEBUG("begin marginalization");
marginalization_info->marginalize();
ROS_DEBUG("end marginalization, %f ms", t_margin.toc());
std::unordered_map<long, double *> addr_shift;
for (int i = 0; i <= WINDOW_SIZE; i++)
{
if (i == WINDOW_SIZE - 1)
continue;
else if (i == WINDOW_SIZE)
{
addr_shift[reinterpret_cast<long>(para_Pose[i])] = para_Pose[i - 1];
if(USE_IMU)
addr_shift[reinterpret_cast<long>(para_SpeedBias[i])] = para_SpeedBias[i - 1];
}
else
{
addr_shift[reinterpret_cast<long>(para_Pose[i])] = para_Pose[i];
if(USE_IMU)
addr_shift[reinterpret_cast<long>(para_SpeedBias[i])] = para_SpeedBias[i];
}
}
for (int i = 0; i < NUM_OF_CAM; i++)
addr_shift[reinterpret_cast<long>(para_Ex_Pose[i])] = para_Ex_Pose[i];
addr_shift[reinterpret_cast<long>(para_Td[0])] = para_Td[0];
vector<double *> parameter_blocks = marginalization_info->getParameterBlocks(addr_shift);
if (last_marginalization_info)
delete last_marginalization_info;
last_marginalization_info = marginalization_info;
last_marginalization_parameter_blocks = parameter_blocks;
}
}
}
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