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Merge pull request #249 from mindThomas/feature/isam2-kitti-example 

Added ported C++ version of ISAM2 Kitti example
release/4.3a0
Frank Dellaert 2020-07-09 15:17:18 -04:00 committed by GitHub
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/* ----------------------------------------------------------------------------
* GTSAM Copyright 2010, Georgia Tech Research Corporation,
* Atlanta, Georgia 30332-0415
* All Rights Reserved
* Authors: Frank Dellaert, et al. (see THANKS for the full author list)
* See LICENSE for the license information
* -------------------------------------------------------------------------- */
/**
* @file IMUKittiExampleGPS
* @brief Example of application of ISAM2 for GPS-aided navigation on the KITTI VISION BENCHMARK SUITE
* @author Ported by Thomas Jespersen (thomasj@tkjelectronics.dk), TKJ Electronics
*/
// GTSAM related includes.
#include <gtsam/navigation/CombinedImuFactor.h>
#include <gtsam/navigation/GPSFactor.h>
#include <gtsam/navigation/ImuFactor.h>
#include <gtsam/slam/dataset.h>
#include <gtsam/slam/BetweenFactor.h>
#include <gtsam/slam/PriorFactor.h>
#include <gtsam/nonlinear/ISAM2.h>
#include <gtsam/nonlinear/ISAM2Params.h>
#include <gtsam/nonlinear/NonlinearFactorGraph.h>
#include <gtsam/inference/Symbol.h>
#include <cstring>
#include <fstream>
#include <iostream>
using namespace std;
using namespace gtsam;
using symbol_shorthand::X; // Pose3 (x,y,z,r,p,y)
using symbol_shorthand::V; // Vel (xdot,ydot,zdot)
using symbol_shorthand::B; // Bias (ax,ay,az,gx,gy,gz)
struct KittiCalibration {
double body_ptx;
double body_pty;
double body_ptz;
double body_prx;
double body_pry;
double body_prz;
double accelerometer_sigma;
double gyroscope_sigma;
double integration_sigma;
double accelerometer_bias_sigma;
double gyroscope_bias_sigma;
double average_delta_t;
};
struct ImuMeasurement {
double time;
double dt;
Vector3 accelerometer;
Vector3 gyroscope; // omega
};
struct GpsMeasurement {
double time;
Vector3 position; // x,y,z
};
const string output_filename = "IMUKittiExampleGPSResults.csv";
void loadKittiData(KittiCalibration& kitti_calibration,
vector<ImuMeasurement>& imu_measurements,
vector<GpsMeasurement>& gps_measurements) {
string line;
// Read IMU metadata and compute relative sensor pose transforms
// BodyPtx BodyPty BodyPtz BodyPrx BodyPry BodyPrz AccelerometerSigma GyroscopeSigma IntegrationSigma
// AccelerometerBiasSigma GyroscopeBiasSigma AverageDeltaT
string imu_metadata_file = findExampleDataFile("KittiEquivBiasedImu_metadata.txt");
ifstream imu_metadata(imu_metadata_file.c_str());
printf("-- Reading sensor metadata\n");
getline(imu_metadata, line, '\n'); // ignore the first line
// Load Kitti calibration
getline(imu_metadata, line, '\n');
sscanf(line.c_str(), "%lf %lf %lf %lf %lf %lf %lf %lf %lf %lf %lf %lf",
&kitti_calibration.body_ptx,
&kitti_calibration.body_pty,
&kitti_calibration.body_ptz,
&kitti_calibration.body_prx,
&kitti_calibration.body_pry,
&kitti_calibration.body_prz,
&kitti_calibration.accelerometer_sigma,
&kitti_calibration.gyroscope_sigma,
&kitti_calibration.integration_sigma,
&kitti_calibration.accelerometer_bias_sigma,
&kitti_calibration.gyroscope_bias_sigma,
&kitti_calibration.average_delta_t);
printf("IMU metadata: %lf %lf %lf %lf %lf %lf %lf %lf %lf %lf %lf %lf\n",
kitti_calibration.body_ptx,
kitti_calibration.body_pty,
kitti_calibration.body_ptz,
kitti_calibration.body_prx,
kitti_calibration.body_pry,
kitti_calibration.body_prz,
kitti_calibration.accelerometer_sigma,
kitti_calibration.gyroscope_sigma,
kitti_calibration.integration_sigma,
kitti_calibration.accelerometer_bias_sigma,
kitti_calibration.gyroscope_bias_sigma,
kitti_calibration.average_delta_t);
// Read IMU data
// Time dt accelX accelY accelZ omegaX omegaY omegaZ
string imu_data_file = findExampleDataFile("KittiEquivBiasedImu.txt");
printf("-- Reading IMU measurements from file\n");
{
ifstream imu_data(imu_data_file.c_str());
getline(imu_data, line, '\n'); // ignore the first line
double time = 0, dt = 0, acc_x = 0, acc_y = 0, acc_z = 0, gyro_x = 0, gyro_y = 0, gyro_z = 0;
while (!imu_data.eof()) {
getline(imu_data, line, '\n');
sscanf(line.c_str(), "%lf %lf %lf %lf %lf %lf %lf %lf",
&time, &dt,
&acc_x, &acc_y, &acc_z,
&gyro_x, &gyro_y, &gyro_z);
ImuMeasurement measurement;
measurement.time = time;
measurement.dt = dt;
measurement.accelerometer = Vector3(acc_x, acc_y, acc_z);
measurement.gyroscope = Vector3(gyro_x, gyro_y, gyro_z);
imu_measurements.push_back(measurement);
}
}
// Read GPS data
// Time,X,Y,Z
string gps_data_file = findExampleDataFile("KittiGps_converted.txt");
printf("-- Reading GPS measurements from file\n");
{
ifstream gps_data(gps_data_file.c_str());
getline(gps_data, line, '\n'); // ignore the first line
double time = 0, gps_x = 0, gps_y = 0, gps_z = 0;
while (!gps_data.eof()) {
getline(gps_data, line, '\n');
sscanf(line.c_str(), "%lf,%lf,%lf,%lf", &time, &gps_x, &gps_y, &gps_z);
GpsMeasurement measurement;
measurement.time = time;
measurement.position = Vector3(gps_x, gps_y, gps_z);
gps_measurements.push_back(measurement);
}
}
}
int main(int argc, char* argv[]) {
KittiCalibration kitti_calibration;
vector<ImuMeasurement> imu_measurements;
vector<GpsMeasurement> gps_measurements;
loadKittiData(kitti_calibration, imu_measurements, gps_measurements);
Vector6 BodyP = (Vector(6) << kitti_calibration.body_ptx, kitti_calibration.body_pty, kitti_calibration.body_ptz,
kitti_calibration.body_prx, kitti_calibration.body_pry, kitti_calibration.body_prz)
.finished();
auto body_T_imu = Pose3::Expmap(BodyP);
if (!body_T_imu.equals(Pose3(), 1e-5)) {
printf("Currently only support IMUinBody is identity, i.e. IMU and body frame are the same");
exit(-1);
}
// Configure different variables
double t_offset = gps_measurements[0].time;
size_t first_gps_pose = 1;
size_t gps_skip = 10; // Skip this many GPS measurements each time
double g = 9.8;
auto w_coriolis = Vector3(); // zero vector
// Configure noise models
auto noise_model_gps = noiseModel::Diagonal::Precisions((Vector(6) << Vector3::Constant(0),
Vector3::Constant(1.0/0.07))
.finished());
// Set initial conditions for the estimated trajectory
// initial pose is the reference frame (navigation frame)
auto current_pose_global = Pose3(Rot3(), gps_measurements[first_gps_pose].position);
auto current_velocity_global = Vector3(); // the vehicle is stationary at the beginning at position 0,0,0
auto current_bias = imuBias::ConstantBias(); // init with zero bias
auto sigma_init_x = noiseModel::Diagonal::Precisions((Vector(6) << Vector3::Constant(0),
Vector3::Constant(1.0))
.finished());
auto sigma_init_v = noiseModel::Diagonal::Sigmas(Vector3::Constant(1000.0));
auto sigma_init_b = noiseModel::Diagonal::Sigmas((Vector(6) << Vector3::Constant(0.100),
Vector3::Constant(5.00e-05))
.finished());
// Set IMU preintegration parameters
Matrix33 measured_acc_cov = I_3x3 * pow(kitti_calibration.accelerometer_sigma, 2);
Matrix33 measured_omega_cov = I_3x3 * pow(kitti_calibration.gyroscope_sigma, 2);
// error committed in integrating position from velocities
Matrix33 integration_error_cov = I_3x3 * pow(kitti_calibration.integration_sigma, 2);
auto imu_params = PreintegratedImuMeasurements::Params::MakeSharedU(g);
imu_params->accelerometerCovariance = measured_acc_cov; // acc white noise in continuous
imu_params->integrationCovariance = integration_error_cov; // integration uncertainty continuous
imu_params->gyroscopeCovariance = measured_omega_cov; // gyro white noise in continuous
imu_params->omegaCoriolis = w_coriolis;
std::shared_ptr<PreintegratedImuMeasurements> current_summarized_measurement = nullptr;
// Set ISAM2 parameters and create ISAM2 solver object
ISAM2Params isam_params;
isam_params.factorization = ISAM2Params::CHOLESKY;
isam_params.relinearizeSkip = 10;
ISAM2 isam(isam_params);
// Create the factor graph and values object that will store new factors and values to add to the incremental graph
NonlinearFactorGraph new_factors;
Values new_values; // values storing the initial estimates of new nodes in the factor graph
/// Main loop:
/// (1) we read the measurements
/// (2) we create the corresponding factors in the graph
/// (3) we solve the graph to obtain and optimal estimate of robot trajectory
printf("-- Starting main loop: inference is performed at each time step, but we plot trajectory every 10 steps\n");
size_t j = 0;
for (size_t i = first_gps_pose; i < gps_measurements.size() - 1; i++) {
// At each non=IMU measurement we initialize a new node in the graph
auto current_pose_key = X(i);
auto current_vel_key = V(i);
auto current_bias_key = B(i);
double t = gps_measurements[i].time;
if (i == first_gps_pose) {
// Create initial estimate and prior on initial pose, velocity, and biases
new_values.insert(current_pose_key, current_pose_global);
new_values.insert(current_vel_key, current_velocity_global);
new_values.insert(current_bias_key, current_bias);
new_factors.emplace_shared<PriorFactor<Pose3>>(current_pose_key, current_pose_global, sigma_init_x);
new_factors.emplace_shared<PriorFactor<Vector3>>(current_vel_key, current_velocity_global, sigma_init_v);
new_factors.emplace_shared<PriorFactor<imuBias::ConstantBias>>(current_bias_key, current_bias, sigma_init_b);
} else {
double t_previous = gps_measurements[i-1].time;
// Summarize IMU data between the previous GPS measurement and now
current_summarized_measurement = std::make_shared<PreintegratedImuMeasurements>(imu_params, current_bias);
static size_t included_imu_measurement_count = 0;
while (j < imu_measurements.size() && imu_measurements[j].time <= t) {
if (imu_measurements[j].time >= t_previous) {
current_summarized_measurement->integrateMeasurement(imu_measurements[j].accelerometer,
imu_measurements[j].gyroscope,
imu_measurements[j].dt);
included_imu_measurement_count++;
}
j++;
}
// Create IMU factor
auto previous_pose_key = X(i-1);
auto previous_vel_key = V(i-1);
auto previous_bias_key = B(i-1);
new_factors.emplace_shared<ImuFactor>(previous_pose_key, previous_vel_key,
current_pose_key, current_vel_key,
previous_bias_key, *current_summarized_measurement);
// Bias evolution as given in the IMU metadata
auto sigma_between_b = noiseModel::Diagonal::Sigmas((Vector(6) <<
Vector3::Constant(sqrt(included_imu_measurement_count) * kitti_calibration.accelerometer_bias_sigma),
Vector3::Constant(sqrt(included_imu_measurement_count) * kitti_calibration.gyroscope_bias_sigma))
.finished());
new_factors.emplace_shared<BetweenFactor<imuBias::ConstantBias>>(previous_bias_key,
current_bias_key,
imuBias::ConstantBias(),
sigma_between_b);
// Create GPS factor
auto gps_pose = Pose3(current_pose_global.rotation(), gps_measurements[i].position);
if ((i % gps_skip) == 0) {
new_factors.emplace_shared<PriorFactor<Pose3>>(current_pose_key, gps_pose, noise_model_gps);
new_values.insert(current_pose_key, gps_pose);
printf("################ POSE INCLUDED AT TIME %lf ################\n", t);
gps_pose.translation().print();
printf("\n\n");
} else {
new_values.insert(current_pose_key, current_pose_global);
}
// Add initial values for velocity and bias based on the previous estimates
new_values.insert(current_vel_key, current_velocity_global);
new_values.insert(current_bias_key, current_bias);
// Update solver
// =======================================================================
// We accumulate 2*GPSskip GPS measurements before updating the solver at
// first so that the heading becomes observable.
if (i > (first_gps_pose + 2*gps_skip)) {
printf("################ NEW FACTORS AT TIME %lf ################\n", t);
new_factors.print();
isam.update(new_factors, new_values);
// Reset the newFactors and newValues list
new_factors.resize(0);
new_values.clear();
// Extract the result/current estimates
Values result = isam.calculateEstimate();
current_pose_global = result.at<Pose3>(current_pose_key);
current_velocity_global = result.at<Vector3>(current_vel_key);
current_bias = result.at<imuBias::ConstantBias>(current_bias_key);
printf("\n################ POSE AT TIME %lf ################\n", t);
current_pose_global.print();
printf("\n\n");
}
}
}
// Save results to file
printf("\nWriting results to file...\n");
FILE* fp_out = fopen(output_filename.c_str(), "w+");
fprintf(fp_out, "#time(s),x(m),y(m),z(m),qx,qy,qz,qw,gt_x(m),gt_y(m),gt_z(m)\n");
Values result = isam.calculateEstimate();
for (size_t i = first_gps_pose; i < gps_measurements.size() - 1; i++) {
auto pose_key = X(i);
auto vel_key = V(i);
auto bias_key = B(i);
auto pose = result.at<Pose3>(pose_key);
auto velocity = result.at<Vector3>(vel_key);
auto bias = result.at<imuBias::ConstantBias>(bias_key);
auto pose_quat = pose.rotation().toQuaternion();
auto gps = gps_measurements[i].position;
fprintf(fp_out, "%f,%f,%f,%f,%f,%f,%f,%f,%f,%f,%f\n",
gps_measurements[i].time,
pose.x(), pose.y(), pose.z(),
pose_quat.x(), pose_quat.y(), pose_quat.z(), pose_quat.w(),
gps(0), gps(1), gps(2));
}
fclose(fp_out);
}