basalt/src/time_alignment.cpp

478 lines
16 KiB
C++

#include <pangolin/display/image_view.h>
#include <pangolin/gl/gldraw.h>
#include <pangolin/image/image.h>
#include <pangolin/image/image_io.h>
#include <pangolin/image/typed_image.h>
#include <pangolin/pangolin.h>
#include <basalt/io/dataset_io.h>
#include <basalt/serialization/headers_serialization.h>
#include <basalt/calibration/calibration.hpp>
#include <experimental/filesystem>
#include <tbb/tbb.h>
#include <CLI/CLI.hpp>
namespace fs = std::experimental::filesystem;
basalt::Calibration<double> calib;
basalt::MocapCalibration<double> mocap_calib;
// Linear time version
double compute_error(int64_t offset,
const std::vector<int64_t> &gyro_timestamps,
const Eigen::vector<Eigen::Vector3d> &gyro_data,
const std::vector<int64_t> &mocap_rot_vel_timestamps,
const Eigen::vector<Eigen::Vector3d> &mocap_rot_vel_data) {
double error = 0;
int num_points = 0;
size_t j = 0;
for (size_t i = 0; i < mocap_rot_vel_timestamps.size(); i++) {
int64_t corrected_time = mocap_rot_vel_timestamps[i] + offset;
while (gyro_timestamps[j] < corrected_time) j++;
if (j >= gyro_timestamps.size()) break;
int64_t dist_j = gyro_timestamps[j] - corrected_time;
int64_t dist_j_m1 = corrected_time - gyro_timestamps[j - 1];
BASALT_ASSERT(dist_j >= 0);
BASALT_ASSERT(dist_j_m1 >= 0);
int idx = dist_j < dist_j_m1 ? j : j - 1;
if (std::min(dist_j, dist_j_m1) > 1e9 / 120) continue;
error += (gyro_data[idx] - mocap_rot_vel_data[i]).norm();
num_points++;
}
return error / num_points;
}
int main(int argc, char **argv) {
tbb::task_scheduler_init init(
tbb::task_scheduler_init::default_num_threads());
std::string dataset_path;
std::string calibration_path;
std::string mocap_calibration_path;
std::string dataset_type;
std::string output_path;
std::string output_error_path;
std::string output_gyro_path;
std::string output_mocap_path;
bool show_gui = true;
CLI::App app{"Calibrate time offset"};
app.add_option("-d,--dataset-path", dataset_path, "Path to dataset")
->required();
app.add_option("--calibration", calibration_path, "Path to calibration file");
app.add_option("--mocap-calibration", mocap_calibration_path,
"Path to mocap calibration file");
app.add_option("--dataset-type", dataset_type, "Dataset type <euroc, bag>.")
->required();
app.add_option("--output", output_path,
"Path to output file with time-offset result");
app.add_option("--output-error", output_error_path,
"Path to output file with error time-series for plotting");
app.add_option(
"--output-gyro", output_gyro_path,
"Path to output file with gyro rotational velocities for plotting");
app.add_option(
"--output-mocap", output_mocap_path,
"Path to output file with mocap rotational velocities for plotting");
app.add_flag("--show-gui", show_gui, "Show GUI for debugging");
try {
app.parse(argc, argv);
} catch (const CLI::ParseError &e) {
return app.exit(e);
}
basalt::VioDatasetPtr vio_dataset;
const bool use_calib =
!(calibration_path.empty() || mocap_calibration_path.empty());
if (use_calib) {
std::ifstream is(calibration_path);
if (is.good()) {
cereal::JSONInputArchive archive(is);
archive(calib);
std::cout << "Loaded calibration from: " << calibration_path << std::endl;
} else {
std::cerr << "No calibration found" << std::endl;
std::abort();
}
std::ifstream mocap_is(mocap_calibration_path);
if (mocap_is.good()) {
cereal::JSONInputArchive archive(mocap_is);
archive(mocap_calib);
std::cout << "Loaded mocap calibration from: " << mocap_calibration_path
<< std::endl;
} else {
std::cerr << "No mocap calibration found" << std::endl;
std::abort();
}
}
basalt::DatasetIoInterfacePtr dataset_io =
basalt::DatasetIoFactory::getDatasetIo(dataset_type);
dataset_io->read(dataset_path);
vio_dataset = dataset_io->get_data();
std::vector<int64_t> gyro_timestamps;
Eigen::vector<Eigen::Vector3d> gyro_data;
std::vector<int64_t> mocap_rot_vel_timestamps;
Eigen::vector<Eigen::Vector3d> mocap_rot_vel_data;
// Apply calibration to gyro
{
int saturation_count = 0;
for (size_t i = 0; i < vio_dataset->get_gyro_data().size(); i++) {
if (vio_dataset->get_gyro_data()[i].data.array().abs().maxCoeff() >
499.0 * M_PI / 180) {
++saturation_count;
continue;
}
gyro_timestamps.push_back(vio_dataset->get_gyro_data()[i].timestamp_ns);
Eigen::Vector3d measurement = vio_dataset->get_gyro_data()[i].data;
if (use_calib) {
gyro_data.push_back(calib.calib_gyro_bias.getCalibrated(measurement));
} else {
gyro_data.push_back(measurement);
}
}
std::cout << "saturated gyro measurement count: " << saturation_count
<< std::endl;
}
// compute rotational velocity from mocap data
{
Sophus::SE3d T_mark_i;
if (use_calib) T_mark_i = mocap_calib.T_i_mark.inverse();
int saturation_count = 0;
for (size_t i = 1; i < vio_dataset->get_gt_timestamps().size() - 1; i++) {
Sophus::SE3d p0, p1;
// compute central differences, to have no timestamp bias
p0 = vio_dataset->get_gt_pose_data()[i - 1] * T_mark_i;
p1 = vio_dataset->get_gt_pose_data()[i + 1] * T_mark_i;
double dt = (vio_dataset->get_gt_timestamps()[i + 1] -
vio_dataset->get_gt_timestamps()[i - 1]) *
1e-9;
// only compute difference, if measurements are really 2 consecutive
// measurements apart (assuming 120 Hz data)
if (dt > 2.5 / 120) continue;
Eigen::Vector3d rot_vel = (p0.so3().inverse() * p1.so3()).log() / dt;
// Filter outliers
if (rot_vel.array().abs().maxCoeff() > 500 * M_PI / 180) {
++saturation_count;
continue;
}
mocap_rot_vel_timestamps.push_back(vio_dataset->get_gt_timestamps()[i]);
mocap_rot_vel_data.push_back(rot_vel);
}
std::cout << "outlier mocap rotation velocity count: " << saturation_count
<< std::endl;
}
std::cout << "gyro_data.size() " << gyro_data.size() << std::endl;
std::cout << "mocap_rot_vel_data.size() " << mocap_rot_vel_data.size()
<< std::endl;
std::vector<double> offsets_vec;
std::vector<double> errors_vec;
int best_offset_ns = 0;
double best_error = std::numeric_limits<double>::max();
int best_error_idx = -1;
int64_t max_offset_ns = 10000000000;
int64_t offset_inc_ns = 100000;
for (int64_t offset_ns = -max_offset_ns; offset_ns <= max_offset_ns;
offset_ns += offset_inc_ns) {
double error = compute_error(offset_ns, gyro_timestamps, gyro_data,
mocap_rot_vel_timestamps, mocap_rot_vel_data);
offsets_vec.push_back(offset_ns * 1e-6);
errors_vec.push_back(error);
if (error < best_error) {
best_error = error;
best_offset_ns = offset_ns;
best_error_idx = errors_vec.size() - 1;
}
}
std::cout << "Best error: " << best_error << std::endl;
std::cout << "Best error idx : " << best_error_idx << std::endl;
std::cout << "Best offset: " << best_offset_ns << std::endl;
pangolin::DataLog error_log;
int best_offset_refined_ns = best_offset_ns;
// Subpixel accuracy
Eigen::Vector3d coeff(0, 0, 0);
{
const static int SAMPLE_INTERVAL = 10;
if (best_error_idx - SAMPLE_INTERVAL >= 0 &&
best_error_idx + SAMPLE_INTERVAL < int(errors_vec.size())) {
Eigen::MatrixXd pol(2 * SAMPLE_INTERVAL + 1, 3);
Eigen::VectorXd err(2 * SAMPLE_INTERVAL + 1);
for (int i = 0; i < 2 * SAMPLE_INTERVAL + 1; i++) {
int idx = i - SAMPLE_INTERVAL;
pol(i, 0) = idx * idx;
pol(i, 1) = idx;
pol(i, 2) = 1;
err(i) = errors_vec[best_error_idx + idx];
}
coeff =
pol.jacobiSvd(Eigen::ComputeThinU | Eigen::ComputeThinV).solve(err);
double a = coeff[0];
double b = coeff[1];
if (a > 1e-9) {
best_offset_refined_ns -= offset_inc_ns * b / (2 * a);
}
}
for (size_t i = 0; i < errors_vec.size(); i++) {
const double idx =
static_cast<double>(static_cast<int>(i) - best_error_idx);
const Eigen::Vector3d pol(idx * idx, idx, 1);
error_log.Log(offsets_vec[i], errors_vec[i], pol.transpose() * coeff);
}
}
std::cout << "Best error refined: "
<< compute_error(best_offset_refined_ns, gyro_timestamps, gyro_data,
mocap_rot_vel_timestamps, mocap_rot_vel_data)
<< std::endl;
std::cout << "Best offset refined: " << best_offset_refined_ns << std::endl;
std::cout << "Total mocap offset: "
<< vio_dataset->get_mocap_to_imu_offset_ns() +
best_offset_refined_ns
<< std::endl;
if (output_path != "") {
std::ofstream os(output_path);
cereal::JSONOutputArchive archive(os);
archive(cereal::make_nvp("mocap_to_imu_initial_offset_ns",
vio_dataset->get_mocap_to_imu_offset_ns()));
archive(cereal::make_nvp("mocap_to_imu_additional_offset_refined_ns",
best_offset_refined_ns));
archive(cereal::make_nvp(
"mocap_to_imu_total_offset_ns",
vio_dataset->get_mocap_to_imu_offset_ns() + best_offset_refined_ns));
}
if (output_error_path != "") {
std::cout << "Writing error time series to '" << output_error_path << "'"
<< std::endl;
std::ofstream os(output_error_path);
os << "#TIME_MS,ERROR,ERROR_FITTED" << std::endl;
os << "# best_offset_ms: " << best_offset_ns * 1e-6
<< ", best_offset_refined_ms: " << best_offset_refined_ns * 1e-6
<< std::endl;
for (size_t i = 0; i < errors_vec.size(); ++i) {
const double idx =
static_cast<double>(static_cast<int>(i) - best_error_idx);
const Eigen::Vector3d pol(idx * idx, idx, 1);
const double fitted = pol.transpose() * coeff;
os << offsets_vec[i] << "," << errors_vec[i] << "," << fitted
<< std::endl;
}
}
int64_t min_time = vio_dataset->get_gyro_data().front().timestamp_ns;
int64_t max_time = vio_dataset->get_gyro_data().back().timestamp_ns;
if (output_gyro_path != "") {
std::cout << "Writing gyro values to '" << output_gyro_path << "'"
<< std::endl;
std::ofstream os(output_gyro_path);
os << "#TIME_M, GX, GY, GZ" << std::endl;
for (size_t i = 0; i < gyro_timestamps.size(); ++i) {
os << (gyro_timestamps[i] - min_time) * 1e-9 << " "
<< gyro_data[i].transpose() << std::endl;
}
}
if (output_mocap_path != "") {
std::cout << "Writing mocap rotational velocity values to '"
<< output_mocap_path << "'" << std::endl;
std::ofstream os(output_mocap_path);
os << "#TIME_M, GX, GY, GZ" << std::endl;
for (size_t i = 0; i < gyro_timestamps.size(); ++i) {
os << (mocap_rot_vel_timestamps[i] + best_offset_ns - min_time) * 1e-9
<< " " << mocap_rot_vel_data[i].transpose() << std::endl;
}
}
if (show_gui) {
static constexpr int UI_WIDTH = 280;
pangolin::CreateWindowAndBind("Main", 1280, 800);
pangolin::Plotter *plotter;
pangolin::DataLog data_log, mocap_log;
pangolin::View &plot_display = pangolin::CreateDisplay().SetBounds(
0.0, 1.0, pangolin::Attach::Pix(UI_WIDTH), 1.0);
pangolin::CreatePanel("ui").SetBounds(0.0, 1.0, 0.0,
pangolin::Attach::Pix(UI_WIDTH));
plotter = new pangolin::Plotter(&data_log, 0, (max_time - min_time) * 1e-9,
-10.0, 10.0, 0.01, 0.01);
plot_display.AddDisplay(*plotter);
pangolin::Var<bool> show_gyro("ui.show_gyro", true, false, true);
pangolin::Var<bool> show_mocap_rot_vel("ui.show_mocap_rot_vel", true, false,
true);
pangolin::Var<bool> show_error("ui.show_error", false, false, true);
pangolin::Var<std::function<void(void)>> save_aligned_dataset(
"ui.save_aligned_dataset", [&]() {
if (fs::exists(fs::path(dataset_path + "mav0/gt/data.csv"))) {
std::cout << "Aligned grount truth data already exists, skipping."
<< std::endl;
return;
}
std::cout << "Saving aligned dataset in "
<< dataset_path + "mav0/gt/data.csv" << std::endl;
// output corrected mocap data
Sophus::SE3d T_mark_i;
if (use_calib) T_mark_i = mocap_calib.T_i_mark.inverse();
fs::create_directory(dataset_path + "mav0/gt/");
std::ofstream gt_out_stream;
gt_out_stream.open(dataset_path + "mav0/gt/data.csv");
gt_out_stream
<< "#timestamp [ns], p_RS_R_x [m], p_RS_R_y [m], p_RS_R_z [m], "
"q_RS_w [], q_RS_x [], q_RS_y [], q_RS_z []\n";
for (size_t i = 0; i < vio_dataset->get_gt_timestamps().size(); i++) {
gt_out_stream << vio_dataset->get_gt_timestamps()[i] +
best_offset_refined_ns
<< ",";
Sophus::SE3d pose_corrected =
vio_dataset->get_gt_pose_data()[i] * T_mark_i;
gt_out_stream << pose_corrected.translation().x() << ","
<< pose_corrected.translation().y() << ","
<< pose_corrected.translation().z() << ","
<< pose_corrected.unit_quaternion().w() << ","
<< pose_corrected.unit_quaternion().x() << ","
<< pose_corrected.unit_quaternion().y() << ","
<< pose_corrected.unit_quaternion().z() << std::endl;
}
gt_out_stream.close();
});
auto recompute_logs = [&]() {
data_log.Clear();
mocap_log.Clear();
for (size_t i = 0; i < gyro_timestamps.size(); i++) {
data_log.Log((gyro_timestamps[i] - min_time) * 1e-9, gyro_data[i][0],
gyro_data[i][1], gyro_data[i][2]);
}
for (size_t i = 0; i < mocap_rot_vel_timestamps.size(); i++) {
mocap_log.Log(
(mocap_rot_vel_timestamps[i] + best_offset_ns - min_time) * 1e-9,
mocap_rot_vel_data[i][0], mocap_rot_vel_data[i][1],
mocap_rot_vel_data[i][2]);
}
};
auto drawPlots = [&]() {
plotter->ClearSeries();
plotter->ClearMarkers();
if (show_gyro) {
plotter->AddSeries("$0", "$1", pangolin::DrawingModeLine,
pangolin::Colour::Red(), "g x");
plotter->AddSeries("$0", "$2", pangolin::DrawingModeLine,
pangolin::Colour::Green(), "g y");
plotter->AddSeries("$0", "$3", pangolin::DrawingModeLine,
pangolin::Colour::Blue(), "g z");
}
if (show_mocap_rot_vel) {
plotter->AddSeries("$0", "$1", pangolin::DrawingModeLine,
pangolin::Colour(1, 1, 0), "pv x", &mocap_log);
plotter->AddSeries("$0", "$2", pangolin::DrawingModeLine,
pangolin::Colour(1, 0, 1), "pv y", &mocap_log);
plotter->AddSeries("$0", "$3", pangolin::DrawingModeLine,
pangolin::Colour(0, 1, 1), "pv z", &mocap_log);
}
if (show_error) {
plotter->AddSeries("$0", "$1", pangolin::DrawingModeLine,
pangolin::Colour(1, 1, 1), "error", &error_log);
plotter->AddSeries("$0", "$2", pangolin::DrawingModeLine,
pangolin::Colour(0.3, 1, 0.8), "fitted error",
&error_log);
plotter->AddMarker(pangolin::Marker::Vertical,
best_offset_refined_ns * 1e-6,
pangolin::Marker::Equal, pangolin::Colour(1, 0, 0));
}
};
recompute_logs();
drawPlots();
while (!pangolin::ShouldQuit()) {
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
if (show_gyro.GuiChanged() || show_mocap_rot_vel.GuiChanged() ||
show_error.GuiChanged()) {
drawPlots();
}
pangolin::FinishFrame();
}
}
return 0;
}