Pull common extrinsics calibration code out into //frc971/vision
This sets us up to have a generic solver interface, and year specific
data munging.
Change-Id: I5cba597aa263d5061b7c71cd617706460ddb5f93
Signed-off-by: Austin Schuh <austin.linux@gmail.com>
diff --git a/frc971/vision/BUILD b/frc971/vision/BUILD
index 1e3ed58..ca35f7c 100644
--- a/frc971/vision/BUILD
+++ b/frc971/vision/BUILD
@@ -33,3 +33,56 @@
"@com_google_absl//absl/base",
],
)
+
+cc_library(
+ name = "charuco_lib",
+ srcs = [
+ "charuco_lib.cc",
+ ],
+ hdrs = [
+ "charuco_lib.h",
+ ],
+ target_compatible_with = ["@platforms//os:linux"],
+ visibility = ["//visibility:public"],
+ deps = [
+ "//aos:flatbuffers",
+ "//aos/events:event_loop",
+ "//aos/network:message_bridge_server_fbs",
+ "//aos/network:team_number",
+ "//frc971/control_loops:quaternion_utils",
+ "//frc971/vision:vision_fbs",
+ "//third_party:opencv",
+ "//y2020/vision/sift:sift_fbs",
+ "//y2020/vision/sift:sift_training_fbs",
+ "//y2020/vision/tools/python_code:sift_training_data",
+ "@com_github_google_glog//:glog",
+ "@com_google_absl//absl/strings:str_format",
+ "@com_google_absl//absl/types:span",
+ "@org_tuxfamily_eigen//:eigen",
+ ],
+)
+
+cc_library(
+ name = "extrinsics_calibration",
+ srcs = [
+ "calibration_accumulator.cc",
+ "calibration_accumulator.h",
+ "extrinsics_calibration.cc",
+ "extrinsics_calibration.h",
+ ],
+ target_compatible_with = ["@platforms//os:linux"],
+ visibility = ["//visibility:public"],
+ deps = [
+ ":charuco_lib",
+ "//aos:init",
+ "//aos/events/logging:log_reader",
+ "//frc971/analysis:in_process_plotter",
+ "//frc971/control_loops/drivetrain:improved_down_estimator",
+ "//frc971/wpilib:imu_batch_fbs",
+ "//frc971/wpilib:imu_fbs",
+ "//third_party:opencv",
+ "@com_google_absl//absl/strings:str_format",
+ "@com_google_ceres_solver//:ceres",
+ "@org_tuxfamily_eigen//:eigen",
+ ],
+)
diff --git a/y2020/vision/calibration_accumulator.cc b/frc971/vision/calibration_accumulator.cc
similarity index 94%
rename from y2020/vision/calibration_accumulator.cc
rename to frc971/vision/calibration_accumulator.cc
index 9f550c5..89945b0 100644
--- a/y2020/vision/calibration_accumulator.cc
+++ b/frc971/vision/calibration_accumulator.cc
@@ -1,4 +1,4 @@
-#include "y2020/vision/calibration_accumulator.h"
+#include "frc971/vision/calibration_accumulator.h"
#include <opencv2/aruco/charuco.hpp>
#include <opencv2/calib3d.hpp>
@@ -11,7 +11,7 @@
#include "aos/time/time.h"
#include "frc971/control_loops/quaternion_utils.h"
#include "frc971/wpilib/imu_batch_generated.h"
-#include "y2020/vision/charuco_lib.h"
+#include "frc971/vision/charuco_lib.h"
DEFINE_bool(display_undistorted, false,
"If true, display the undistorted image.");
@@ -38,7 +38,7 @@
imu_points_.emplace_back(distributed_now, std::make_pair(gyro, accel));
}
-void CalibrationData::ReviewData(CalibrationDataObserver *observer) {
+void CalibrationData::ReviewData(CalibrationDataObserver *observer) const {
size_t next_imu_point = 0;
size_t next_camera_point = 0;
while (true) {
@@ -116,13 +116,6 @@
data_->AddCameraPose(image_factory_->ToDistributedClock(eof), rvec_eigen,
tvec_eigen);
- // TODO(austin): Need a gravity vector input.
- //
- // TODO(austin): Need a state, covariance, and model.
- //
- // TODO(austin): Need to record all the values out of a log and run it
- // as a batch run so we can feed it into ceres.
-
// Z -> up
// Y -> away from cameras 2 and 3
// X -> left
diff --git a/y2020/vision/calibration_accumulator.h b/frc971/vision/calibration_accumulator.h
similarity index 96%
rename from y2020/vision/calibration_accumulator.h
rename to frc971/vision/calibration_accumulator.h
index 7bff9f0..6d42708 100644
--- a/y2020/vision/calibration_accumulator.h
+++ b/frc971/vision/calibration_accumulator.h
@@ -7,8 +7,8 @@
#include "aos/events/simulated_event_loop.h"
#include "aos/time/time.h"
#include "frc971/control_loops/quaternion_utils.h"
+#include "frc971/vision/charuco_lib.h"
#include "frc971/wpilib/imu_batch_generated.h"
-#include "y2020/vision/charuco_lib.h"
namespace frc971 {
namespace vision {
@@ -42,7 +42,7 @@
// Processes the data points by calling UpdateCamera and UpdateIMU in time
// order.
- void ReviewData(CalibrationDataObserver *observer);
+ void ReviewData(CalibrationDataObserver *observer) const;
size_t camera_samples_size() const { return rot_trans_points_.size(); }
diff --git a/y2020/vision/charuco_lib.cc b/frc971/vision/charuco_lib.cc
similarity index 99%
rename from y2020/vision/charuco_lib.cc
rename to frc971/vision/charuco_lib.cc
index 8677cbb..f14c9fd 100644
--- a/y2020/vision/charuco_lib.cc
+++ b/frc971/vision/charuco_lib.cc
@@ -1,12 +1,12 @@
-#include "y2020/vision/charuco_lib.h"
+#include "frc971/vision/charuco_lib.h"
#include <chrono>
#include <functional>
-#include <string_view>
-
#include <opencv2/core/eigen.hpp>
#include <opencv2/highgui/highgui.hpp>
#include <opencv2/imgproc.hpp>
+#include <string_view>
+
#include "aos/events/event_loop.h"
#include "aos/flatbuffers.h"
#include "aos/network/team_number.h"
diff --git a/y2020/vision/charuco_lib.h b/frc971/vision/charuco_lib.h
similarity index 100%
rename from y2020/vision/charuco_lib.h
rename to frc971/vision/charuco_lib.h
diff --git a/frc971/vision/extrinsics_calibration.cc b/frc971/vision/extrinsics_calibration.cc
new file mode 100644
index 0000000..627769b
--- /dev/null
+++ b/frc971/vision/extrinsics_calibration.cc
@@ -0,0 +1,634 @@
+#include "frc971/vision/extrinsics_calibration.h"
+
+#include "aos/time/time.h"
+#include "ceres/ceres.h"
+#include "frc971/analysis/in_process_plotter.h"
+#include "frc971/control_loops/runge_kutta.h"
+#include "frc971/vision/calibration_accumulator.h"
+#include "frc971/vision/charuco_lib.h"
+
+namespace frc971 {
+namespace vision {
+
+namespace chrono = std::chrono;
+using aos::distributed_clock;
+using aos::monotonic_clock;
+
+constexpr double kGravity = 9.8;
+
+// The basic ideas here are taken from Kalibr.
+// (https://github.com/ethz-asl/kalibr), but adapted to work with AOS, and to be
+// simpler.
+//
+// Camera readings and IMU readings come in at different times, on different
+// time scales. Our first problem is to align them in time so we can actually
+// compute an error. This is done in the calibration accumulator code. The
+// kalibr paper uses splines, while this uses kalman filters to solve the same
+// interpolation problem so we can get the expected vs actual pose at the time
+// each image arrives.
+//
+// The cost function is then fed the computed angular and positional error for
+// each camera sample before the kalman filter update. Intuitively, the smaller
+// the corrections to the kalman filter each step, the better the estimate
+// should be.
+//
+// We don't actually implement the angular kalman filter because the IMU is so
+// good. We give the solver an initial position and bias, and let it solve from
+// there. This lets us represent drift that is linear in time, which should be
+// good enough for ~1 minute calibration.
+//
+// TODO(austin): Kalman smoother ala
+// https://stanford.edu/~boyd/papers/pdf/auto_ks.pdf should allow for better
+// parallelism, and since we aren't causal, will take that into account a lot
+// better.
+
+// This class takes the initial parameters and biases, and computes the error
+// between the measured and expected camera readings. When optimized, this
+// gives us a cost function to minimize.
+template <typename Scalar>
+class CeresPoseFilter : public CalibrationDataObserver {
+ public:
+ typedef Eigen::Transform<Scalar, 3, Eigen::Affine> Affine3s;
+
+ CeresPoseFilter(Eigen::Quaternion<Scalar> initial_orientation,
+ Eigen::Quaternion<Scalar> imu_to_camera,
+ Eigen::Matrix<Scalar, 3, 1> gyro_bias,
+ Eigen::Matrix<Scalar, 6, 1> initial_state,
+ Eigen::Quaternion<Scalar> board_to_world,
+ Eigen::Matrix<Scalar, 3, 1> imu_to_camera_translation,
+ Scalar gravity_scalar,
+ Eigen::Matrix<Scalar, 3, 1> accelerometer_bias)
+ : accel_(Eigen::Matrix<double, 3, 1>::Zero()),
+ omega_(Eigen::Matrix<double, 3, 1>::Zero()),
+ imu_bias_(gyro_bias),
+ orientation_(initial_orientation),
+ x_hat_(initial_state),
+ p_(Eigen::Matrix<Scalar, 6, 6>::Zero()),
+ imu_to_camera_rotation_(imu_to_camera),
+ imu_to_camera_translation_(imu_to_camera_translation),
+ board_to_world_(board_to_world),
+ gravity_scalar_(gravity_scalar),
+ accelerometer_bias_(accelerometer_bias) {}
+
+ Scalar gravity_scalar() { return gravity_scalar_; }
+
+ virtual void ObserveCameraUpdate(
+ distributed_clock::time_point /*t*/,
+ Eigen::Vector3d /*board_to_camera_rotation*/,
+ Eigen::Quaternion<Scalar> /*imu_to_world_rotation*/,
+ Affine3s /*imu_to_world*/) {}
+
+ // Observes a camera measurement by applying a kalman filter correction and
+ // accumulating up the error associated with the step.
+ void UpdateCamera(distributed_clock::time_point t,
+ std::pair<Eigen::Vector3d, Eigen::Vector3d> rt) override {
+ Integrate(t);
+
+ const Eigen::Quaternion<Scalar> board_to_camera_rotation(
+ frc971::controls::ToQuaternionFromRotationVector(rt.first)
+ .cast<Scalar>());
+ const Affine3s board_to_camera =
+ Eigen::Translation3d(rt.second).cast<Scalar>() *
+ board_to_camera_rotation;
+
+ const Affine3s imu_to_camera =
+ imu_to_camera_translation_ * imu_to_camera_rotation_;
+
+ // This converts us from (facing the board),
+ // x right, y up, z towards us -> x right, y away, z up.
+ // Confirmed to be right.
+
+ // Want world -> imu rotation.
+ // world <- board <- camera <- imu.
+ const Eigen::Quaternion<Scalar> imu_to_world_rotation =
+ board_to_world_ * board_to_camera_rotation.inverse() *
+ imu_to_camera_rotation_;
+
+ const Affine3s imu_to_world =
+ board_to_world_ * board_to_camera.inverse() * imu_to_camera;
+
+ const Eigen::Matrix<Scalar, 3, 1> z =
+ imu_to_world * Eigen::Matrix<Scalar, 3, 1>::Zero();
+
+ Eigen::Matrix<Scalar, 3, 6> H = Eigen::Matrix<Scalar, 3, 6>::Zero();
+ H(0, 0) = static_cast<Scalar>(1.0);
+ H(1, 1) = static_cast<Scalar>(1.0);
+ H(2, 2) = static_cast<Scalar>(1.0);
+ const Eigen::Matrix<Scalar, 3, 1> y = z - H * x_hat_;
+
+ const Eigen::Matrix<double, 3, 3> R =
+ (::Eigen::DiagonalMatrix<double, 3>().diagonal() << ::std::pow(0.01, 2),
+ ::std::pow(0.01, 2), ::std::pow(0.01, 2))
+ .finished()
+ .asDiagonal();
+
+ const Eigen::Matrix<Scalar, 3, 3> S =
+ H * p_ * H.transpose() + R.cast<Scalar>();
+ const Eigen::Matrix<Scalar, 6, 3> K = p_ * H.transpose() * S.inverse();
+
+ x_hat_ += K * y;
+ p_ = (Eigen::Matrix<Scalar, 6, 6>::Identity() - K * H) * p_;
+
+ const Eigen::Quaternion<Scalar> error(imu_to_world_rotation.inverse() *
+ orientation());
+
+ errors_.emplace_back(
+ Eigen::Matrix<Scalar, 3, 1>(error.x(), error.y(), error.z()));
+ position_errors_.emplace_back(y);
+
+ ObserveCameraUpdate(t, rt.first, imu_to_world_rotation, imu_to_world);
+ }
+
+ virtual void ObserveIMUUpdate(
+ distributed_clock::time_point /*t*/,
+ std::pair<Eigen::Vector3d, Eigen::Vector3d> /*wa*/) {}
+
+ void UpdateIMU(distributed_clock::time_point t,
+ std::pair<Eigen::Vector3d, Eigen::Vector3d> wa) override {
+ Integrate(t);
+ omega_ = wa.first;
+ accel_ = wa.second;
+
+ ObserveIMUUpdate(t, wa);
+ }
+
+ const Eigen::Quaternion<Scalar> &orientation() const { return orientation_; }
+
+ size_t num_errors() const { return errors_.size(); }
+ Scalar errorx(size_t i) const { return errors_[i].x(); }
+ Scalar errory(size_t i) const { return errors_[i].y(); }
+ Scalar errorz(size_t i) const { return errors_[i].z(); }
+
+ size_t num_perrors() const { return position_errors_.size(); }
+ Scalar errorpx(size_t i) const { return position_errors_[i].x(); }
+ Scalar errorpy(size_t i) const { return position_errors_[i].y(); }
+ Scalar errorpz(size_t i) const { return position_errors_[i].z(); }
+
+ private:
+ Eigen::Matrix<Scalar, 46, 1> Pack(Eigen::Quaternion<Scalar> q,
+ Eigen::Matrix<Scalar, 6, 1> x_hat,
+ Eigen::Matrix<Scalar, 6, 6> p) {
+ Eigen::Matrix<Scalar, 46, 1> result = Eigen::Matrix<Scalar, 46, 1>::Zero();
+ result.template block<4, 1>(0, 0) = q.coeffs();
+ result.template block<6, 1>(4, 0) = x_hat;
+ result.template block<36, 1>(10, 0) =
+ Eigen::Map<Eigen::Matrix<Scalar, 36, 1>>(p.data(), p.size());
+
+ return result;
+ }
+
+ std::tuple<Eigen::Quaternion<Scalar>, Eigen::Matrix<Scalar, 6, 1>,
+ Eigen::Matrix<Scalar, 6, 6>>
+ UnPack(Eigen::Matrix<Scalar, 46, 1> input) {
+ Eigen::Quaternion<Scalar> q(input.template block<4, 1>(0, 0));
+ Eigen::Matrix<Scalar, 6, 1> x_hat(input.template block<6, 1>(4, 0));
+ Eigen::Matrix<Scalar, 6, 6> p =
+ Eigen::Map<Eigen::Matrix<Scalar, 6, 6>>(input.data() + 10, 6, 6);
+ return std::make_tuple(q, x_hat, p);
+ }
+
+ Eigen::Matrix<Scalar, 46, 1> Derivative(
+ const Eigen::Matrix<Scalar, 46, 1> &input) {
+ auto [q, x_hat, p] = UnPack(input);
+
+ Eigen::Quaternion<Scalar> omega_q;
+ omega_q.w() = Scalar(0.0);
+ omega_q.vec() = 0.5 * (omega_.cast<Scalar>() - imu_bias_);
+ Eigen::Matrix<Scalar, 4, 1> q_dot = (q * omega_q).coeffs();
+
+ Eigen::Matrix<double, 6, 6> A = Eigen::Matrix<double, 6, 6>::Zero();
+ A(0, 3) = 1.0;
+ A(1, 4) = 1.0;
+ A(2, 5) = 1.0;
+
+ Eigen::Matrix<Scalar, 6, 1> x_hat_dot = A * x_hat;
+ x_hat_dot.template block<3, 1>(3, 0) =
+ orientation() * (accel_.cast<Scalar>() - accelerometer_bias_) -
+ Eigen::Vector3d(0, 0, kGravity).cast<Scalar>() * gravity_scalar_;
+
+ // Initialize the position noise to 0. If the solver is going to back-solve
+ // for the most likely starting position, let's just say that the noise is
+ // small.
+ constexpr double kPositionNoise = 0.0;
+ constexpr double kAccelerometerNoise = 2.3e-6 * 9.8;
+ constexpr double kIMUdt = 5.0e-4;
+ Eigen::Matrix<double, 6, 6> Q_dot(
+ (::Eigen::DiagonalMatrix<double, 6>().diagonal()
+ << ::std::pow(kPositionNoise, 2) / kIMUdt,
+ ::std::pow(kPositionNoise, 2) / kIMUdt,
+ ::std::pow(kPositionNoise, 2) / kIMUdt,
+ ::std::pow(kAccelerometerNoise, 2) / kIMUdt,
+ ::std::pow(kAccelerometerNoise, 2) / kIMUdt,
+ ::std::pow(kAccelerometerNoise, 2) / kIMUdt)
+ .finished()
+ .asDiagonal());
+ Eigen::Matrix<Scalar, 6, 6> p_dot = A.cast<Scalar>() * p +
+ p * A.transpose().cast<Scalar>() +
+ Q_dot.cast<Scalar>();
+
+ return Pack(Eigen::Quaternion<Scalar>(q_dot), x_hat_dot, p_dot);
+ }
+
+ virtual void ObserveIntegrated(distributed_clock::time_point /*t*/,
+ Eigen::Matrix<Scalar, 6, 1> /*x_hat*/,
+ Eigen::Quaternion<Scalar> /*orientation*/,
+ Eigen::Matrix<Scalar, 6, 6> /*p*/) {}
+
+ void Integrate(distributed_clock::time_point t) {
+ if (last_time_ != distributed_clock::min_time) {
+ Eigen::Matrix<Scalar, 46, 1> next = control_loops::RungeKutta(
+ [this](auto r) { return Derivative(r); },
+ Pack(orientation_, x_hat_, p_),
+ aos::time::DurationInSeconds(t - last_time_));
+
+ std::tie(orientation_, x_hat_, p_) = UnPack(next);
+
+ // Normalize q so it doesn't drift.
+ orientation_.normalize();
+ }
+
+ last_time_ = t;
+ ObserveIntegrated(t, x_hat_, orientation_, p_);
+ }
+
+ Eigen::Matrix<double, 3, 1> accel_;
+ Eigen::Matrix<double, 3, 1> omega_;
+ Eigen::Matrix<Scalar, 3, 1> imu_bias_;
+
+ // IMU -> world quaternion
+ Eigen::Quaternion<Scalar> orientation_;
+ Eigen::Matrix<Scalar, 6, 1> x_hat_;
+ Eigen::Matrix<Scalar, 6, 6> p_;
+ distributed_clock::time_point last_time_ = distributed_clock::min_time;
+
+ Eigen::Quaternion<Scalar> imu_to_camera_rotation_;
+ Eigen::Translation<Scalar, 3> imu_to_camera_translation_ =
+ Eigen::Translation3d(0, 0, 0).cast<Scalar>();
+
+ Eigen::Quaternion<Scalar> board_to_world_;
+ Scalar gravity_scalar_;
+ Eigen::Matrix<Scalar, 3, 1> accelerometer_bias_;
+ // States:
+ // xyz position
+ // xyz velocity
+ //
+ // Inputs
+ // xyz accel
+ //
+ // Measurement:
+ // xyz position from camera.
+ //
+ // Since the gyro is so good, we can just solve for the bias and initial
+ // position with the solver and see what it learns.
+
+ // Returns the angular errors for each camera sample.
+ std::vector<Eigen::Matrix<Scalar, 3, 1>> errors_;
+ std::vector<Eigen::Matrix<Scalar, 3, 1>> position_errors_;
+};
+
+// Subclass of the filter above which has plotting. This keeps debug code and
+// actual code separate.
+class PoseFilter : public CeresPoseFilter<double> {
+ public:
+ PoseFilter(Eigen::Quaternion<double> initial_orientation,
+ Eigen::Quaternion<double> imu_to_camera,
+ Eigen::Matrix<double, 3, 1> gyro_bias,
+ Eigen::Matrix<double, 6, 1> initial_state,
+ Eigen::Quaternion<double> board_to_world,
+ Eigen::Matrix<double, 3, 1> imu_to_camera_translation,
+ double gravity_scalar,
+ Eigen::Matrix<double, 3, 1> accelerometer_bias)
+ : CeresPoseFilter<double>(initial_orientation, imu_to_camera, gyro_bias,
+ initial_state, board_to_world,
+ imu_to_camera_translation, gravity_scalar,
+ accelerometer_bias) {}
+
+ void Plot() {
+ std::vector<double> rx;
+ std::vector<double> ry;
+ std::vector<double> rz;
+ std::vector<double> x;
+ std::vector<double> y;
+ std::vector<double> z;
+ std::vector<double> vx;
+ std::vector<double> vy;
+ std::vector<double> vz;
+ for (const Eigen::Quaternion<double> &q : orientations_) {
+ Eigen::Matrix<double, 3, 1> rotation_vector =
+ frc971::controls::ToRotationVectorFromQuaternion(q);
+ rx.emplace_back(rotation_vector(0, 0));
+ ry.emplace_back(rotation_vector(1, 0));
+ rz.emplace_back(rotation_vector(2, 0));
+ }
+ for (const Eigen::Matrix<double, 6, 1> &x_hat : x_hats_) {
+ x.emplace_back(x_hat(0));
+ y.emplace_back(x_hat(1));
+ z.emplace_back(x_hat(2));
+ vx.emplace_back(x_hat(3));
+ vy.emplace_back(x_hat(4));
+ vz.emplace_back(x_hat(5));
+ }
+
+ frc971::analysis::Plotter plotter;
+ plotter.AddFigure("position");
+ plotter.AddLine(times_, rx, "x_hat(0)");
+ plotter.AddLine(times_, ry, "x_hat(1)");
+ plotter.AddLine(times_, rz, "x_hat(2)");
+ plotter.AddLine(ct, cx, "Camera x");
+ plotter.AddLine(ct, cy, "Camera y");
+ plotter.AddLine(ct, cz, "Camera z");
+ plotter.AddLine(ct, cerrx, "Camera error x");
+ plotter.AddLine(ct, cerry, "Camera error y");
+ plotter.AddLine(ct, cerrz, "Camera error z");
+ plotter.Publish();
+
+ plotter.AddFigure("error");
+ plotter.AddLine(times_, rx, "x_hat(0)");
+ plotter.AddLine(times_, ry, "x_hat(1)");
+ plotter.AddLine(times_, rz, "x_hat(2)");
+ plotter.AddLine(ct, cerrx, "Camera error x");
+ plotter.AddLine(ct, cerry, "Camera error y");
+ plotter.AddLine(ct, cerrz, "Camera error z");
+ plotter.Publish();
+
+ plotter.AddFigure("imu");
+ plotter.AddLine(ct, world_gravity_x, "world_gravity(0)");
+ plotter.AddLine(ct, world_gravity_y, "world_gravity(1)");
+ plotter.AddLine(ct, world_gravity_z, "world_gravity(2)");
+ plotter.AddLine(imut, imu_x, "imu x");
+ plotter.AddLine(imut, imu_y, "imu y");
+ plotter.AddLine(imut, imu_z, "imu z");
+ plotter.AddLine(times_, rx, "rotation x");
+ plotter.AddLine(times_, ry, "rotation y");
+ plotter.AddLine(times_, rz, "rotation z");
+ plotter.Publish();
+
+ plotter.AddFigure("raw");
+ plotter.AddLine(imut, imu_x, "imu x");
+ plotter.AddLine(imut, imu_y, "imu y");
+ plotter.AddLine(imut, imu_z, "imu z");
+ plotter.AddLine(imut, imu_ratex, "omega x");
+ plotter.AddLine(imut, imu_ratey, "omega y");
+ plotter.AddLine(imut, imu_ratez, "omega z");
+ plotter.AddLine(ct, raw_cx, "Camera x");
+ plotter.AddLine(ct, raw_cy, "Camera y");
+ plotter.AddLine(ct, raw_cz, "Camera z");
+ plotter.Publish();
+
+ plotter.AddFigure("xyz vel");
+ plotter.AddLine(times_, x, "x");
+ plotter.AddLine(times_, y, "y");
+ plotter.AddLine(times_, z, "z");
+ plotter.AddLine(times_, vx, "vx");
+ plotter.AddLine(times_, vy, "vy");
+ plotter.AddLine(times_, vz, "vz");
+ plotter.AddLine(ct, camera_position_x, "Camera x");
+ plotter.AddLine(ct, camera_position_y, "Camera y");
+ plotter.AddLine(ct, camera_position_z, "Camera z");
+ plotter.Publish();
+
+ plotter.Spin();
+ }
+
+ void ObserveIntegrated(distributed_clock::time_point t,
+ Eigen::Matrix<double, 6, 1> x_hat,
+ Eigen::Quaternion<double> orientation,
+ Eigen::Matrix<double, 6, 6> p) override {
+ VLOG(1) << t << " -> " << p;
+ VLOG(1) << t << " xhat -> " << x_hat.transpose();
+ times_.emplace_back(chrono::duration<double>(t.time_since_epoch()).count());
+ x_hats_.emplace_back(x_hat);
+ orientations_.emplace_back(orientation);
+ }
+
+ void ObserveIMUUpdate(
+ distributed_clock::time_point t,
+ std::pair<Eigen::Vector3d, Eigen::Vector3d> wa) override {
+ imut.emplace_back(chrono::duration<double>(t.time_since_epoch()).count());
+ imu_ratex.emplace_back(wa.first.x());
+ imu_ratey.emplace_back(wa.first.y());
+ imu_ratez.emplace_back(wa.first.z());
+ imu_x.emplace_back(wa.second.x());
+ imu_y.emplace_back(wa.second.y());
+ imu_z.emplace_back(wa.second.z());
+
+ last_accel_ = wa.second;
+ }
+
+ void ObserveCameraUpdate(distributed_clock::time_point t,
+ Eigen::Vector3d board_to_camera_rotation,
+ Eigen::Quaternion<double> imu_to_world_rotation,
+ Eigen::Affine3d imu_to_world) override {
+ raw_cx.emplace_back(board_to_camera_rotation(0, 0));
+ raw_cy.emplace_back(board_to_camera_rotation(1, 0));
+ raw_cz.emplace_back(board_to_camera_rotation(2, 0));
+
+ Eigen::Matrix<double, 3, 1> rotation_vector =
+ frc971::controls::ToRotationVectorFromQuaternion(imu_to_world_rotation);
+ ct.emplace_back(chrono::duration<double>(t.time_since_epoch()).count());
+
+ Eigen::Matrix<double, 3, 1> cerr =
+ frc971::controls::ToRotationVectorFromQuaternion(
+ imu_to_world_rotation.inverse() * orientation());
+
+ cx.emplace_back(rotation_vector(0, 0));
+ cy.emplace_back(rotation_vector(1, 0));
+ cz.emplace_back(rotation_vector(2, 0));
+
+ cerrx.emplace_back(cerr(0, 0));
+ cerry.emplace_back(cerr(1, 0));
+ cerrz.emplace_back(cerr(2, 0));
+
+ const Eigen::Vector3d world_gravity =
+ imu_to_world_rotation * last_accel_ -
+ Eigen::Vector3d(0, 0, kGravity) * gravity_scalar();
+
+ const Eigen::Vector3d camera_position =
+ imu_to_world * Eigen::Vector3d::Zero();
+
+ world_gravity_x.emplace_back(world_gravity.x());
+ world_gravity_y.emplace_back(world_gravity.y());
+ world_gravity_z.emplace_back(world_gravity.z());
+
+ camera_position_x.emplace_back(camera_position.x());
+ camera_position_y.emplace_back(camera_position.y());
+ camera_position_z.emplace_back(camera_position.z());
+ }
+
+ std::vector<double> ct;
+ std::vector<double> cx;
+ std::vector<double> cy;
+ std::vector<double> cz;
+ std::vector<double> raw_cx;
+ std::vector<double> raw_cy;
+ std::vector<double> raw_cz;
+ std::vector<double> cerrx;
+ std::vector<double> cerry;
+ std::vector<double> cerrz;
+
+ std::vector<double> world_gravity_x;
+ std::vector<double> world_gravity_y;
+ std::vector<double> world_gravity_z;
+ std::vector<double> imu_x;
+ std::vector<double> imu_y;
+ std::vector<double> imu_z;
+ std::vector<double> camera_position_x;
+ std::vector<double> camera_position_y;
+ std::vector<double> camera_position_z;
+
+ std::vector<double> imut;
+ std::vector<double> imu_ratex;
+ std::vector<double> imu_ratey;
+ std::vector<double> imu_ratez;
+
+ std::vector<double> times_;
+ std::vector<Eigen::Matrix<double, 6, 1>> x_hats_;
+ std::vector<Eigen::Quaternion<double>> orientations_;
+
+ Eigen::Matrix<double, 3, 1> last_accel_ = Eigen::Matrix<double, 3, 1>::Zero();
+};
+
+// Adapter class from the KF above to a Ceres cost function.
+struct CostFunctor {
+ CostFunctor(const CalibrationData *d) : data(d) {}
+
+ const CalibrationData *data;
+
+ template <typename S>
+ bool operator()(const S *const q1, const S *const q2, const S *const v,
+ const S *const p, const S *const btw, const S *const itc,
+ const S *const gravity_scalar_ptr,
+ const S *const accelerometer_bias_ptr, S *residual) const {
+ Eigen::Quaternion<S> initial_orientation(q1[3], q1[0], q1[1], q1[2]);
+ Eigen::Quaternion<S> mounting_orientation(q2[3], q2[0], q2[1], q2[2]);
+ Eigen::Quaternion<S> board_to_world(btw[3], btw[0], btw[1], btw[2]);
+ Eigen::Matrix<S, 3, 1> gyro_bias(v[0], v[1], v[2]);
+ Eigen::Matrix<S, 6, 1> initial_state;
+ initial_state(0) = p[0];
+ initial_state(1) = p[1];
+ initial_state(2) = p[2];
+ initial_state(3) = p[3];
+ initial_state(4) = p[4];
+ initial_state(5) = p[5];
+ Eigen::Matrix<S, 3, 1> imu_to_camera_translation(itc[0], itc[1], itc[2]);
+ Eigen::Matrix<S, 3, 1> accelerometer_bias(accelerometer_bias_ptr[0],
+ accelerometer_bias_ptr[1],
+ accelerometer_bias_ptr[2]);
+
+ CeresPoseFilter<S> filter(initial_orientation, mounting_orientation,
+ gyro_bias, initial_state, board_to_world,
+ imu_to_camera_translation, *gravity_scalar_ptr,
+ accelerometer_bias);
+ data->ReviewData(&filter);
+
+ for (size_t i = 0; i < filter.num_errors(); ++i) {
+ residual[3 * i + 0] = filter.errorx(i);
+ residual[3 * i + 1] = filter.errory(i);
+ residual[3 * i + 2] = filter.errorz(i);
+ }
+
+ for (size_t i = 0; i < filter.num_perrors(); ++i) {
+ residual[3 * filter.num_errors() + 3 * i + 0] = filter.errorpx(i);
+ residual[3 * filter.num_errors() + 3 * i + 1] = filter.errorpy(i);
+ residual[3 * filter.num_errors() + 3 * i + 2] = filter.errorpz(i);
+ }
+
+ return true;
+ }
+};
+
+void Solve(const CalibrationData &data,
+ CalibrationParameters *calibration_parameters) {
+ ceres::Problem problem;
+
+ ceres::EigenQuaternionParameterization *quaternion_local_parameterization =
+ new ceres::EigenQuaternionParameterization();
+ // Set up the only cost function (also known as residual). This uses
+ // auto-differentiation to obtain the derivative (jacobian).
+
+ ceres::CostFunction *cost_function =
+ new ceres::AutoDiffCostFunction<CostFunctor, ceres::DYNAMIC, 4, 4, 3, 6,
+ 4, 3, 1, 3>(
+ new CostFunctor(&data), data.camera_samples_size() * 6);
+ problem.AddResidualBlock(
+ cost_function, new ceres::HuberLoss(1.0),
+ calibration_parameters->initial_orientation.coeffs().data(),
+ calibration_parameters->imu_to_camera.coeffs().data(),
+ calibration_parameters->gyro_bias.data(),
+ calibration_parameters->initial_state.data(),
+ calibration_parameters->board_to_world.coeffs().data(),
+ calibration_parameters->imu_to_camera_translation.data(),
+ &calibration_parameters->gravity_scalar,
+ calibration_parameters->accelerometer_bias.data());
+ problem.SetParameterization(
+ calibration_parameters->initial_orientation.coeffs().data(),
+ quaternion_local_parameterization);
+ problem.SetParameterization(
+ calibration_parameters->imu_to_camera.coeffs().data(),
+ quaternion_local_parameterization);
+ problem.SetParameterization(
+ calibration_parameters->board_to_world.coeffs().data(),
+ quaternion_local_parameterization);
+ for (int i = 0; i < 3; ++i) {
+ problem.SetParameterLowerBound(calibration_parameters->gyro_bias.data(), i,
+ -0.05);
+ problem.SetParameterUpperBound(calibration_parameters->gyro_bias.data(), i,
+ 0.05);
+ problem.SetParameterLowerBound(
+ calibration_parameters->accelerometer_bias.data(), i, -0.05);
+ problem.SetParameterUpperBound(
+ calibration_parameters->accelerometer_bias.data(), i, 0.05);
+ }
+ problem.SetParameterLowerBound(&calibration_parameters->gravity_scalar, 0,
+ 0.95);
+ problem.SetParameterUpperBound(&calibration_parameters->gravity_scalar, 0,
+ 1.05);
+
+ // Run the solver!
+ ceres::Solver::Options options;
+ options.minimizer_progress_to_stdout = true;
+ options.gradient_tolerance = 1e-12;
+ options.function_tolerance = 1e-16;
+ options.parameter_tolerance = 1e-12;
+ ceres::Solver::Summary summary;
+ Solve(options, &problem, &summary);
+ LOG(INFO) << summary.FullReport();
+
+ LOG(INFO) << "initial_orientation "
+ << calibration_parameters->initial_orientation.coeffs().transpose();
+ LOG(INFO) << "imu_to_camera "
+ << calibration_parameters->imu_to_camera.coeffs().transpose();
+ LOG(INFO) << "imu_to_camera(rotation) "
+ << frc971::controls::ToRotationVectorFromQuaternion(
+ calibration_parameters->imu_to_camera)
+ .transpose();
+ LOG(INFO) << "gyro_bias " << calibration_parameters->gyro_bias.transpose();
+ LOG(INFO) << "board_to_world "
+ << calibration_parameters->board_to_world.coeffs().transpose();
+ LOG(INFO) << "board_to_world(rotation) "
+ << frc971::controls::ToRotationVectorFromQuaternion(
+ calibration_parameters->board_to_world)
+ .transpose();
+ LOG(INFO) << "imu_to_camera_translation "
+ << calibration_parameters->imu_to_camera_translation.transpose();
+ LOG(INFO) << "gravity " << kGravity * calibration_parameters->gravity_scalar;
+ LOG(INFO) << "accelerometer bias "
+ << calibration_parameters->accelerometer_bias.transpose();
+}
+
+void Plot(const CalibrationData &data,
+ const CalibrationParameters &calibration_parameters) {
+ PoseFilter filter(calibration_parameters.initial_orientation,
+ calibration_parameters.imu_to_camera,
+ calibration_parameters.gyro_bias,
+ calibration_parameters.initial_state,
+ calibration_parameters.board_to_world,
+ calibration_parameters.imu_to_camera_translation,
+ calibration_parameters.gravity_scalar,
+ calibration_parameters.accelerometer_bias);
+ data.ReviewData(&filter);
+ filter.Plot();
+}
+
+} // namespace vision
+} // namespace frc971
diff --git a/frc971/vision/extrinsics_calibration.h b/frc971/vision/extrinsics_calibration.h
new file mode 100644
index 0000000..9d6c704
--- /dev/null
+++ b/frc971/vision/extrinsics_calibration.h
@@ -0,0 +1,39 @@
+#ifndef FRC971_VISION_EXTRINSICS_CALIBRATION_H_
+#define FRC971_VISION_EXTRINSICS_CALIBRATION_H_
+
+#include "Eigen/Dense"
+#include "Eigen/Geometry"
+#include "frc971/vision/calibration_accumulator.h"
+
+namespace frc971 {
+namespace vision {
+
+struct CalibrationParameters {
+ Eigen::Quaternion<double> initial_orientation =
+ Eigen::Quaternion<double>::Identity();
+ Eigen::Quaternion<double> imu_to_camera =
+ Eigen::Quaternion<double>::Identity();
+ Eigen::Quaternion<double> board_to_world =
+ Eigen::Quaternion<double>::Identity();
+
+ Eigen::Vector3d gyro_bias = Eigen::Vector3d::Zero();
+ Eigen::Matrix<double, 6, 1> initial_state =
+ Eigen::Matrix<double, 6, 1>::Zero();
+ Eigen::Matrix<double, 3, 1> imu_to_camera_translation =
+ Eigen::Matrix<double, 3, 1>::Zero();
+
+ double gravity_scalar = 1.0;
+ Eigen::Matrix<double, 3, 1> accelerometer_bias =
+ Eigen::Matrix<double, 3, 1>::Zero();
+};
+
+void Solve(const CalibrationData &data,
+ CalibrationParameters *calibration_parameters);
+
+void Plot(const CalibrationData &data,
+ const CalibrationParameters &calibration_parameters);
+
+} // namespace vision
+} // namespace frc971
+
+#endif // FRC971_VISION_EXTRINSICS_CALIBRATION_H_
diff --git a/y2020/vision/BUILD b/y2020/vision/BUILD
index ae4e3f2..de85213 100644
--- a/y2020/vision/BUILD
+++ b/y2020/vision/BUILD
@@ -69,34 +69,6 @@
],
)
-cc_library(
- name = "charuco_lib",
- srcs = [
- "charuco_lib.cc",
- ],
- hdrs = [
- "charuco_lib.h",
- ],
- target_compatible_with = ["@platforms//os:linux"],
- visibility = ["//y2020:__subpackages__"],
- deps = [
- "//aos:flatbuffers",
- "//aos/events:event_loop",
- "//aos/network:message_bridge_server_fbs",
- "//aos/network:team_number",
- "//frc971/control_loops:quaternion_utils",
- "//frc971/vision:vision_fbs",
- "//third_party:opencv",
- "//y2020/vision/sift:sift_fbs",
- "//y2020/vision/sift:sift_training_fbs",
- "//y2020/vision/tools/python_code:sift_training_data",
- "@com_github_google_glog//:glog",
- "@com_google_absl//absl/strings:str_format",
- "@com_google_absl//absl/types:span",
- "@org_tuxfamily_eigen//:eigen",
- ],
-)
-
cc_binary(
name = "calibration",
srcs = [
@@ -111,10 +83,10 @@
"//y2022:__subpackages__",
],
deps = [
- ":charuco_lib",
"//aos:init",
"//aos/events:shm_event_loop",
"//frc971/control_loops/drivetrain:improved_down_estimator",
+ "//frc971/vision:charuco_lib",
"//frc971/vision:vision_fbs",
"//frc971/wpilib:imu_batch_fbs",
"//frc971/wpilib:imu_fbs",
@@ -149,27 +121,13 @@
cc_binary(
name = "extrinsics_calibration",
srcs = [
- "calibration_accumulator.cc",
- "calibration_accumulator.h",
"extrinsics_calibration.cc",
],
- data = [
- "//y2020:aos_config",
- ],
target_compatible_with = ["@platforms//os:linux"],
visibility = ["//y2020:__subpackages__"],
deps = [
- ":charuco_lib",
"//aos:init",
- "//aos/events:shm_event_loop",
"//aos/events/logging:log_reader",
- "//frc971/analysis:in_process_plotter",
- "//frc971/control_loops/drivetrain:improved_down_estimator",
- "//frc971/wpilib:imu_batch_fbs",
- "//frc971/wpilib:imu_fbs",
- "//third_party:opencv",
- "@com_google_absl//absl/strings:str_format",
- "@com_google_ceres_solver//:ceres",
- "@org_tuxfamily_eigen//:eigen",
+ "//frc971/vision:extrinsics_calibration",
],
)
diff --git a/y2020/vision/calibration.cc b/y2020/vision/calibration.cc
index 0a12d70..1109b58 100644
--- a/y2020/vision/calibration.cc
+++ b/y2020/vision/calibration.cc
@@ -12,7 +12,7 @@
#include "aos/network/team_number.h"
#include "aos/time/time.h"
#include "aos/util/file.h"
-#include "y2020/vision/charuco_lib.h"
+#include "frc971/vision/charuco_lib.h"
DEFINE_string(calibration_folder, ".", "Folder to place calibration files.");
DEFINE_string(camera_id, "", "Camera ID in format YY-NN-- year and number.");
diff --git a/y2020/vision/extrinsics_calibration.cc b/y2020/vision/extrinsics_calibration.cc
index 5f08527..c54a5cf 100644
--- a/y2020/vision/extrinsics_calibration.cc
+++ b/y2020/vision/extrinsics_calibration.cc
@@ -3,19 +3,14 @@
#include "absl/strings/str_format.h"
#include "aos/events/logging/log_reader.h"
-#include "aos/events/shm_event_loop.h"
#include "aos/init.h"
#include "aos/network/team_number.h"
#include "aos/time/time.h"
#include "aos/util/file.h"
-#include "ceres/ceres.h"
-#include "frc971/analysis/in_process_plotter.h"
-#include "frc971/control_loops/drivetrain/improved_down_estimator.h"
#include "frc971/control_loops/quaternion_utils.h"
#include "frc971/vision/vision_generated.h"
+#include "frc971/vision/extrinsics_calibration.h"
#include "frc971/wpilib/imu_batch_generated.h"
-#include "y2020/vision/calibration_accumulator.h"
-#include "y2020/vision/charuco_lib.h"
#include "y2020/vision/sift/sift_generated.h"
#include "y2020/vision/sift/sift_training_generated.h"
#include "y2020/vision/tools/python_code/sift_training_data.h"
@@ -30,529 +25,6 @@
using aos::distributed_clock;
using aos::monotonic_clock;
-constexpr double kGravity = 9.8;
-
-// The basic ideas here are taken from Kalibr.
-// (https://github.com/ethz-asl/kalibr), but adapted to work with AOS, and to be
-// simpler.
-//
-// Camera readings and IMU readings come in at different times, on different
-// time scales. Our first problem is to align them in time so we can actually
-// compute an error. This is done in the calibration accumulator code. The
-// kalibr paper uses splines, while this uses kalman filters to solve the same
-// interpolation problem so we can get the expected vs actual pose at the time
-// each image arrives.
-//
-// The cost function is then fed the computed angular and positional error for
-// each camera sample before the kalman filter update. Intuitively, the smaller
-// the corrections to the kalman filter each step, the better the estimate
-// should be.
-//
-// We don't actually implement the angular kalman filter because the IMU is so
-// good. We give the solver an initial position and bias, and let it solve from
-// there. This lets us represent drift that is linear in time, which should be
-// good enough for ~1 minute calibration.
-//
-// TODO(austin): Kalman smoother ala
-// https://stanford.edu/~boyd/papers/pdf/auto_ks.pdf should allow for better
-// parallelism, and since we aren't causal, will take that into account a lot
-// better.
-
-// This class takes the initial parameters and biases, and computes the error
-// between the measured and expected camera readings. When optimized, this
-// gives us a cost function to minimize.
-template <typename Scalar>
-class CeresPoseFilter : public CalibrationDataObserver {
- public:
- typedef Eigen::Transform<Scalar, 3, Eigen::Affine> Affine3s;
-
- CeresPoseFilter(Eigen::Quaternion<Scalar> initial_orientation,
- Eigen::Quaternion<Scalar> imu_to_camera,
- Eigen::Matrix<Scalar, 3, 1> gyro_bias,
- Eigen::Matrix<Scalar, 6, 1> initial_state,
- Eigen::Quaternion<Scalar> board_to_world,
- Eigen::Matrix<Scalar, 3, 1> imu_to_camera_translation,
- Scalar gravity_scalar,
- Eigen::Matrix<Scalar, 3, 1> accelerometer_bias)
- : accel_(Eigen::Matrix<double, 3, 1>::Zero()),
- omega_(Eigen::Matrix<double, 3, 1>::Zero()),
- imu_bias_(gyro_bias),
- orientation_(initial_orientation),
- x_hat_(initial_state),
- p_(Eigen::Matrix<Scalar, 6, 6>::Zero()),
- imu_to_camera_rotation_(imu_to_camera),
- imu_to_camera_translation_(imu_to_camera_translation),
- board_to_world_(board_to_world),
- gravity_scalar_(gravity_scalar),
- accelerometer_bias_(accelerometer_bias) {}
-
- Scalar gravity_scalar() { return gravity_scalar_; }
-
- virtual void ObserveCameraUpdate(
- distributed_clock::time_point /*t*/,
- Eigen::Vector3d /*board_to_camera_rotation*/,
- Eigen::Quaternion<Scalar> /*imu_to_world_rotation*/,
- Affine3s /*imu_to_world*/) {}
-
- // Observes a camera measurement by applying a kalman filter correction and
- // accumulating up the error associated with the step.
- void UpdateCamera(distributed_clock::time_point t,
- std::pair<Eigen::Vector3d, Eigen::Vector3d> rt) override {
- Integrate(t);
-
- const Eigen::Quaternion<Scalar> board_to_camera_rotation(
- frc971::controls::ToQuaternionFromRotationVector(rt.first)
- .cast<Scalar>());
- const Affine3s board_to_camera =
- Eigen::Translation3d(rt.second).cast<Scalar>() *
- board_to_camera_rotation;
-
- const Affine3s imu_to_camera =
- imu_to_camera_translation_ * imu_to_camera_rotation_;
-
- // This converts us from (facing the board),
- // x right, y up, z towards us -> x right, y away, z up.
- // Confirmed to be right.
-
- // Want world -> imu rotation.
- // world <- board <- camera <- imu.
- const Eigen::Quaternion<Scalar> imu_to_world_rotation =
- board_to_world_ * board_to_camera_rotation.inverse() *
- imu_to_camera_rotation_;
-
- const Affine3s imu_to_world =
- board_to_world_ * board_to_camera.inverse() * imu_to_camera;
-
- const Eigen::Matrix<Scalar, 3, 1> z =
- imu_to_world * Eigen::Matrix<Scalar, 3, 1>::Zero();
-
- Eigen::Matrix<Scalar, 3, 6> H = Eigen::Matrix<Scalar, 3, 6>::Zero();
- H(0, 0) = static_cast<Scalar>(1.0);
- H(1, 1) = static_cast<Scalar>(1.0);
- H(2, 2) = static_cast<Scalar>(1.0);
- const Eigen::Matrix<Scalar, 3, 1> y = z - H * x_hat_;
-
- const Eigen::Matrix<double, 3, 3> R =
- (::Eigen::DiagonalMatrix<double, 3>().diagonal() << ::std::pow(0.01, 2),
- ::std::pow(0.01, 2), ::std::pow(0.01, 2))
- .finished()
- .asDiagonal();
-
- const Eigen::Matrix<Scalar, 3, 3> S =
- H * p_ * H.transpose() + R.cast<Scalar>();
- const Eigen::Matrix<Scalar, 6, 3> K = p_ * H.transpose() * S.inverse();
-
- x_hat_ += K * y;
- p_ = (Eigen::Matrix<Scalar, 6, 6>::Identity() - K * H) * p_;
-
- const Eigen::Quaternion<Scalar> error(imu_to_world_rotation.inverse() *
- orientation());
-
- errors_.emplace_back(
- Eigen::Matrix<Scalar, 3, 1>(error.x(), error.y(), error.z()));
- position_errors_.emplace_back(y);
-
- ObserveCameraUpdate(t, rt.first, imu_to_world_rotation, imu_to_world);
- }
-
- virtual void ObserveIMUUpdate(
- distributed_clock::time_point /*t*/,
- std::pair<Eigen::Vector3d, Eigen::Vector3d> /*wa*/) {}
-
- void UpdateIMU(distributed_clock::time_point t,
- std::pair<Eigen::Vector3d, Eigen::Vector3d> wa) override {
- Integrate(t);
- omega_ = wa.first;
- accel_ = wa.second;
-
- ObserveIMUUpdate(t, wa);
- }
-
- const Eigen::Quaternion<Scalar> &orientation() const { return orientation_; }
-
- size_t num_errors() const { return errors_.size(); }
- Scalar errorx(size_t i) const { return errors_[i].x(); }
- Scalar errory(size_t i) const { return errors_[i].y(); }
- Scalar errorz(size_t i) const { return errors_[i].z(); }
-
- size_t num_perrors() const { return position_errors_.size(); }
- Scalar errorpx(size_t i) const { return position_errors_[i].x(); }
- Scalar errorpy(size_t i) const { return position_errors_[i].y(); }
- Scalar errorpz(size_t i) const { return position_errors_[i].z(); }
-
- private:
- Eigen::Matrix<Scalar, 46, 1> Pack(Eigen::Quaternion<Scalar> q,
- Eigen::Matrix<Scalar, 6, 1> x_hat,
- Eigen::Matrix<Scalar, 6, 6> p) {
- Eigen::Matrix<Scalar, 46, 1> result = Eigen::Matrix<Scalar, 46, 1>::Zero();
- result.template block<4, 1>(0, 0) = q.coeffs();
- result.template block<6, 1>(4, 0) = x_hat;
- result.template block<36, 1>(10, 0) =
- Eigen::Map<Eigen::Matrix<Scalar, 36, 1>>(p.data(), p.size());
-
- return result;
- }
-
- std::tuple<Eigen::Quaternion<Scalar>, Eigen::Matrix<Scalar, 6, 1>,
- Eigen::Matrix<Scalar, 6, 6>>
- UnPack(Eigen::Matrix<Scalar, 46, 1> input) {
- Eigen::Quaternion<Scalar> q(input.template block<4, 1>(0, 0));
- Eigen::Matrix<Scalar, 6, 1> x_hat(input.template block<6, 1>(4, 0));
- Eigen::Matrix<Scalar, 6, 6> p =
- Eigen::Map<Eigen::Matrix<Scalar, 6, 6>>(input.data() + 10, 6, 6);
- return std::make_tuple(q, x_hat, p);
- }
-
- Eigen::Matrix<Scalar, 46, 1> Derivative(
- const Eigen::Matrix<Scalar, 46, 1> &input) {
- auto [q, x_hat, p] = UnPack(input);
-
- Eigen::Quaternion<Scalar> omega_q;
- omega_q.w() = Scalar(0.0);
- omega_q.vec() = 0.5 * (omega_.cast<Scalar>() - imu_bias_);
- Eigen::Matrix<Scalar, 4, 1> q_dot = (q * omega_q).coeffs();
-
- Eigen::Matrix<double, 6, 6> A = Eigen::Matrix<double, 6, 6>::Zero();
- A(0, 3) = 1.0;
- A(1, 4) = 1.0;
- A(2, 5) = 1.0;
-
- Eigen::Matrix<Scalar, 6, 1> x_hat_dot = A * x_hat;
- x_hat_dot.template block<3, 1>(3, 0) =
- orientation() * (accel_.cast<Scalar>() - accelerometer_bias_) -
- Eigen::Vector3d(0, 0, kGravity).cast<Scalar>() * gravity_scalar_;
-
- // Initialize the position noise to 0. If the solver is going to back-solve
- // for the most likely starting position, let's just say that the noise is
- // small.
- constexpr double kPositionNoise = 0.0;
- constexpr double kAccelerometerNoise = 2.3e-6 * 9.8;
- constexpr double kIMUdt = 5.0e-4;
- Eigen::Matrix<double, 6, 6> Q_dot(
- (::Eigen::DiagonalMatrix<double, 6>().diagonal()
- << ::std::pow(kPositionNoise, 2) / kIMUdt,
- ::std::pow(kPositionNoise, 2) / kIMUdt,
- ::std::pow(kPositionNoise, 2) / kIMUdt,
- ::std::pow(kAccelerometerNoise, 2) / kIMUdt,
- ::std::pow(kAccelerometerNoise, 2) / kIMUdt,
- ::std::pow(kAccelerometerNoise, 2) / kIMUdt)
- .finished()
- .asDiagonal());
- Eigen::Matrix<Scalar, 6, 6> p_dot = A.cast<Scalar>() * p +
- p * A.transpose().cast<Scalar>() +
- Q_dot.cast<Scalar>();
-
- return Pack(Eigen::Quaternion<Scalar>(q_dot), x_hat_dot, p_dot);
- }
-
- virtual void ObserveIntegrated(distributed_clock::time_point /*t*/,
- Eigen::Matrix<Scalar, 6, 1> /*x_hat*/,
- Eigen::Quaternion<Scalar> /*orientation*/,
- Eigen::Matrix<Scalar, 6, 6> /*p*/) {}
-
- void Integrate(distributed_clock::time_point t) {
- if (last_time_ != distributed_clock::min_time) {
- Eigen::Matrix<Scalar, 46, 1> next = control_loops::RungeKutta(
- [this](auto r) { return Derivative(r); },
- Pack(orientation_, x_hat_, p_),
- aos::time::DurationInSeconds(t - last_time_));
-
- std::tie(orientation_, x_hat_, p_) = UnPack(next);
-
- // Normalize q so it doesn't drift.
- orientation_.normalize();
- }
-
- last_time_ = t;
- ObserveIntegrated(t, x_hat_, orientation_, p_);
- }
-
- Eigen::Matrix<double, 3, 1> accel_;
- Eigen::Matrix<double, 3, 1> omega_;
- Eigen::Matrix<Scalar, 3, 1> imu_bias_;
-
- // IMU -> world quaternion
- Eigen::Quaternion<Scalar> orientation_;
- Eigen::Matrix<Scalar, 6, 1> x_hat_;
- Eigen::Matrix<Scalar, 6, 6> p_;
- distributed_clock::time_point last_time_ = distributed_clock::min_time;
-
- Eigen::Quaternion<Scalar> imu_to_camera_rotation_;
- Eigen::Translation<Scalar, 3> imu_to_camera_translation_ =
- Eigen::Translation3d(0, 0, 0).cast<Scalar>();
-
- Eigen::Quaternion<Scalar> board_to_world_;
- Scalar gravity_scalar_;
- Eigen::Matrix<Scalar, 3, 1> accelerometer_bias_;
- // States:
- // xyz position
- // xyz velocity
- //
- // Inputs
- // xyz accel
- //
- // Measurement:
- // xyz position from camera.
- //
- // Since the gyro is so good, we can just solve for the bias and initial
- // position with the solver and see what it learns.
-
- // Returns the angular errors for each camera sample.
- std::vector<Eigen::Matrix<Scalar, 3, 1>> errors_;
- std::vector<Eigen::Matrix<Scalar, 3, 1>> position_errors_;
-};
-
-// Subclass of the filter above which has plotting. This keeps debug code and
-// actual code separate.
-class PoseFilter : public CeresPoseFilter<double> {
- public:
- PoseFilter(Eigen::Quaternion<double> initial_orientation,
- Eigen::Quaternion<double> imu_to_camera,
- Eigen::Matrix<double, 3, 1> gyro_bias,
- Eigen::Matrix<double, 6, 1> initial_state,
- Eigen::Quaternion<double> board_to_world,
- Eigen::Matrix<double, 3, 1> imu_to_camera_translation,
- double gravity_scalar,
- Eigen::Matrix<double, 3, 1> accelerometer_bias)
- : CeresPoseFilter<double>(initial_orientation, imu_to_camera, gyro_bias,
- initial_state, board_to_world,
- imu_to_camera_translation, gravity_scalar,
- accelerometer_bias) {}
-
- void Plot() {
- std::vector<double> rx;
- std::vector<double> ry;
- std::vector<double> rz;
- std::vector<double> x;
- std::vector<double> y;
- std::vector<double> z;
- std::vector<double> vx;
- std::vector<double> vy;
- std::vector<double> vz;
- for (const Eigen::Quaternion<double> &q : orientations_) {
- Eigen::Matrix<double, 3, 1> rotation_vector =
- frc971::controls::ToRotationVectorFromQuaternion(q);
- rx.emplace_back(rotation_vector(0, 0));
- ry.emplace_back(rotation_vector(1, 0));
- rz.emplace_back(rotation_vector(2, 0));
- }
- for (const Eigen::Matrix<double, 6, 1> &x_hat : x_hats_) {
- x.emplace_back(x_hat(0));
- y.emplace_back(x_hat(1));
- z.emplace_back(x_hat(2));
- vx.emplace_back(x_hat(3));
- vy.emplace_back(x_hat(4));
- vz.emplace_back(x_hat(5));
- }
-
- frc971::analysis::Plotter plotter;
- plotter.AddFigure("position");
- plotter.AddLine(times_, rx, "x_hat(0)");
- plotter.AddLine(times_, ry, "x_hat(1)");
- plotter.AddLine(times_, rz, "x_hat(2)");
- plotter.AddLine(ct, cx, "Camera x");
- plotter.AddLine(ct, cy, "Camera y");
- plotter.AddLine(ct, cz, "Camera z");
- plotter.AddLine(ct, cerrx, "Camera error x");
- plotter.AddLine(ct, cerry, "Camera error y");
- plotter.AddLine(ct, cerrz, "Camera error z");
- plotter.Publish();
-
- plotter.AddFigure("error");
- plotter.AddLine(times_, rx, "x_hat(0)");
- plotter.AddLine(times_, ry, "x_hat(1)");
- plotter.AddLine(times_, rz, "x_hat(2)");
- plotter.AddLine(ct, cerrx, "Camera error x");
- plotter.AddLine(ct, cerry, "Camera error y");
- plotter.AddLine(ct, cerrz, "Camera error z");
- plotter.Publish();
-
- plotter.AddFigure("imu");
- plotter.AddLine(ct, world_gravity_x, "world_gravity(0)");
- plotter.AddLine(ct, world_gravity_y, "world_gravity(1)");
- plotter.AddLine(ct, world_gravity_z, "world_gravity(2)");
- plotter.AddLine(imut, imu_x, "imu x");
- plotter.AddLine(imut, imu_y, "imu y");
- plotter.AddLine(imut, imu_z, "imu z");
- plotter.AddLine(times_, rx, "rotation x");
- plotter.AddLine(times_, ry, "rotation y");
- plotter.AddLine(times_, rz, "rotation z");
- plotter.Publish();
-
- plotter.AddFigure("raw");
- plotter.AddLine(imut, imu_x, "imu x");
- plotter.AddLine(imut, imu_y, "imu y");
- plotter.AddLine(imut, imu_z, "imu z");
- plotter.AddLine(imut, imu_ratex, "omega x");
- plotter.AddLine(imut, imu_ratey, "omega y");
- plotter.AddLine(imut, imu_ratez, "omega z");
- plotter.AddLine(ct, raw_cx, "Camera x");
- plotter.AddLine(ct, raw_cy, "Camera y");
- plotter.AddLine(ct, raw_cz, "Camera z");
- plotter.Publish();
-
- plotter.AddFigure("xyz vel");
- plotter.AddLine(times_, x, "x");
- plotter.AddLine(times_, y, "y");
- plotter.AddLine(times_, z, "z");
- plotter.AddLine(times_, vx, "vx");
- plotter.AddLine(times_, vy, "vy");
- plotter.AddLine(times_, vz, "vz");
- plotter.AddLine(ct, camera_position_x, "Camera x");
- plotter.AddLine(ct, camera_position_y, "Camera y");
- plotter.AddLine(ct, camera_position_z, "Camera z");
- plotter.Publish();
-
- plotter.Spin();
- }
-
- void ObserveIntegrated(distributed_clock::time_point t,
- Eigen::Matrix<double, 6, 1> x_hat,
- Eigen::Quaternion<double> orientation,
- Eigen::Matrix<double, 6, 6> p) override {
- VLOG(1) << t << " -> " << p;
- VLOG(1) << t << " xhat -> " << x_hat.transpose();
- times_.emplace_back(chrono::duration<double>(t.time_since_epoch()).count());
- x_hats_.emplace_back(x_hat);
- orientations_.emplace_back(orientation);
- }
-
- void ObserveIMUUpdate(
- distributed_clock::time_point t,
- std::pair<Eigen::Vector3d, Eigen::Vector3d> wa) override {
- imut.emplace_back(chrono::duration<double>(t.time_since_epoch()).count());
- imu_ratex.emplace_back(wa.first.x());
- imu_ratey.emplace_back(wa.first.y());
- imu_ratez.emplace_back(wa.first.z());
- imu_x.emplace_back(wa.second.x());
- imu_y.emplace_back(wa.second.y());
- imu_z.emplace_back(wa.second.z());
-
- last_accel_ = wa.second;
- }
-
- void ObserveCameraUpdate(distributed_clock::time_point t,
- Eigen::Vector3d board_to_camera_rotation,
- Eigen::Quaternion<double> imu_to_world_rotation,
- Eigen::Affine3d imu_to_world) override {
- raw_cx.emplace_back(board_to_camera_rotation(0, 0));
- raw_cy.emplace_back(board_to_camera_rotation(1, 0));
- raw_cz.emplace_back(board_to_camera_rotation(2, 0));
-
- Eigen::Matrix<double, 3, 1> rotation_vector =
- frc971::controls::ToRotationVectorFromQuaternion(imu_to_world_rotation);
- ct.emplace_back(chrono::duration<double>(t.time_since_epoch()).count());
-
- Eigen::Matrix<double, 3, 1> cerr =
- frc971::controls::ToRotationVectorFromQuaternion(
- imu_to_world_rotation.inverse() * orientation());
-
- cx.emplace_back(rotation_vector(0, 0));
- cy.emplace_back(rotation_vector(1, 0));
- cz.emplace_back(rotation_vector(2, 0));
-
- cerrx.emplace_back(cerr(0, 0));
- cerry.emplace_back(cerr(1, 0));
- cerrz.emplace_back(cerr(2, 0));
-
- const Eigen::Vector3d world_gravity =
- imu_to_world_rotation * last_accel_ -
- Eigen::Vector3d(0, 0, kGravity) * gravity_scalar();
-
- const Eigen::Vector3d camera_position =
- imu_to_world * Eigen::Vector3d::Zero();
-
- world_gravity_x.emplace_back(world_gravity.x());
- world_gravity_y.emplace_back(world_gravity.y());
- world_gravity_z.emplace_back(world_gravity.z());
-
- camera_position_x.emplace_back(camera_position.x());
- camera_position_y.emplace_back(camera_position.y());
- camera_position_z.emplace_back(camera_position.z());
- }
-
- std::vector<double> ct;
- std::vector<double> cx;
- std::vector<double> cy;
- std::vector<double> cz;
- std::vector<double> raw_cx;
- std::vector<double> raw_cy;
- std::vector<double> raw_cz;
- std::vector<double> cerrx;
- std::vector<double> cerry;
- std::vector<double> cerrz;
-
- std::vector<double> world_gravity_x;
- std::vector<double> world_gravity_y;
- std::vector<double> world_gravity_z;
- std::vector<double> imu_x;
- std::vector<double> imu_y;
- std::vector<double> imu_z;
- std::vector<double> camera_position_x;
- std::vector<double> camera_position_y;
- std::vector<double> camera_position_z;
-
- std::vector<double> imut;
- std::vector<double> imu_ratex;
- std::vector<double> imu_ratey;
- std::vector<double> imu_ratez;
-
- std::vector<double> times_;
- std::vector<Eigen::Matrix<double, 6, 1>> x_hats_;
- std::vector<Eigen::Quaternion<double>> orientations_;
-
- Eigen::Matrix<double, 3, 1> last_accel_ = Eigen::Matrix<double, 3, 1>::Zero();
-};
-
-// Adapter class from the KF above to a Ceres cost function.
-struct CostFunctor {
- CostFunctor(CalibrationData *d) : data(d) {}
-
- CalibrationData *data;
-
- template <typename S>
- bool operator()(const S *const q1, const S *const q2, const S *const v,
- const S *const p, const S *const btw, const S *const itc,
- const S *const gravity_scalar_ptr,
- const S *const accelerometer_bias_ptr, S *residual) const {
- Eigen::Quaternion<S> initial_orientation(q1[3], q1[0], q1[1], q1[2]);
- Eigen::Quaternion<S> mounting_orientation(q2[3], q2[0], q2[1], q2[2]);
- Eigen::Quaternion<S> board_to_world(btw[3], btw[0], btw[1], btw[2]);
- Eigen::Matrix<S, 3, 1> gyro_bias(v[0], v[1], v[2]);
- Eigen::Matrix<S, 6, 1> initial_state;
- initial_state(0) = p[0];
- initial_state(1) = p[1];
- initial_state(2) = p[2];
- initial_state(3) = p[3];
- initial_state(4) = p[4];
- initial_state(5) = p[5];
- Eigen::Matrix<S, 3, 1> imu_to_camera_translation(itc[0], itc[1], itc[2]);
- Eigen::Matrix<S, 3, 1> accelerometer_bias(accelerometer_bias_ptr[0],
- accelerometer_bias_ptr[1],
- accelerometer_bias_ptr[2]);
-
- CeresPoseFilter<S> filter(initial_orientation, mounting_orientation,
- gyro_bias, initial_state, board_to_world,
- imu_to_camera_translation, *gravity_scalar_ptr,
- accelerometer_bias);
- data->ReviewData(&filter);
-
- for (size_t i = 0; i < filter.num_errors(); ++i) {
- residual[3 * i + 0] = filter.errorx(i);
- residual[3 * i + 1] = filter.errory(i);
- residual[3 * i + 2] = filter.errorz(i);
- }
-
- for (size_t i = 0; i < filter.num_perrors(); ++i) {
- residual[3 * filter.num_errors() + 3 * i + 0] = filter.errorpx(i);
- residual[3 * filter.num_errors() + 3 * i + 1] = filter.errorpy(i);
- residual[3 * filter.num_errors() + 3 * i + 2] = filter.errorpz(i);
- }
-
- return true;
- }
-};
-
void Main(int argc, char **argv) {
CalibrationData data;
@@ -604,104 +76,30 @@
const Eigen::Quaternion<double> nominal_board_to_world(
Eigen::AngleAxisd(0.5 * M_PI, Eigen::Vector3d::UnitX()));
- Eigen::Quaternion<double> initial_orientation = nominal_initial_orientation;
- // Eigen::Quaternion<double>::Identity();
- Eigen::Quaternion<double> imu_to_camera = nominal_imu_to_camera;
- // Eigen::Quaternion<double>::Identity();
- Eigen::Quaternion<double> board_to_world = nominal_board_to_world;
- // Eigen::Quaternion<double>::Identity();
- Eigen::Vector3d gyro_bias = Eigen::Vector3d::Zero();
- Eigen::Matrix<double, 6, 1> initial_state =
- Eigen::Matrix<double, 6, 1>::Zero();
- Eigen::Matrix<double, 3, 1> imu_to_camera_translation =
- Eigen::Matrix<double, 3, 1>::Zero();
+ CalibrationParameters calibration_parameters;
+ calibration_parameters.initial_orientation = nominal_initial_orientation;
+ calibration_parameters.imu_to_camera = nominal_imu_to_camera;
+ calibration_parameters.board_to_world = nominal_board_to_world;
- double gravity_scalar = 1.0;
- Eigen::Matrix<double, 3, 1> accelerometer_bias =
- Eigen::Matrix<double, 3, 1>::Zero();
+ Solve(data, &calibration_parameters);
+ LOG(INFO) << "Nominal initial_orientation "
+ << nominal_initial_orientation.coeffs().transpose();
+ LOG(INFO) << "Nominal imu_to_camera "
+ << nominal_imu_to_camera.coeffs().transpose();
- {
- ceres::Problem problem;
+ LOG(INFO) << "imu_to_camera delta "
+ << frc971::controls::ToRotationVectorFromQuaternion(
+ calibration_parameters.imu_to_camera *
+ nominal_imu_to_camera.inverse())
+ .transpose();
+ LOG(INFO) << "board_to_world delta "
+ << frc971::controls::ToRotationVectorFromQuaternion(
+ calibration_parameters.board_to_world *
+ nominal_board_to_world.inverse())
+ .transpose();
- ceres::EigenQuaternionParameterization *quaternion_local_parameterization =
- new ceres::EigenQuaternionParameterization();
- // Set up the only cost function (also known as residual). This uses
- // auto-differentiation to obtain the derivative (jacobian).
-
- ceres::CostFunction *cost_function =
- new ceres::AutoDiffCostFunction<CostFunctor, ceres::DYNAMIC, 4, 4, 3, 6,
- 4, 3, 1, 3>(
- new CostFunctor(&data), data.camera_samples_size() * 6);
- problem.AddResidualBlock(
- cost_function, new ceres::HuberLoss(1.0),
- initial_orientation.coeffs().data(), imu_to_camera.coeffs().data(),
- gyro_bias.data(), initial_state.data(), board_to_world.coeffs().data(),
- imu_to_camera_translation.data(), &gravity_scalar,
- accelerometer_bias.data());
- problem.SetParameterization(initial_orientation.coeffs().data(),
- quaternion_local_parameterization);
- problem.SetParameterization(imu_to_camera.coeffs().data(),
- quaternion_local_parameterization);
- problem.SetParameterization(board_to_world.coeffs().data(),
- quaternion_local_parameterization);
- for (int i = 0; i < 3; ++i) {
- problem.SetParameterLowerBound(gyro_bias.data(), i, -0.05);
- problem.SetParameterUpperBound(gyro_bias.data(), i, 0.05);
- problem.SetParameterLowerBound(accelerometer_bias.data(), i, -0.05);
- problem.SetParameterUpperBound(accelerometer_bias.data(), i, 0.05);
- }
- problem.SetParameterLowerBound(&gravity_scalar, 0, 0.95);
- problem.SetParameterUpperBound(&gravity_scalar, 0, 1.05);
-
- // Run the solver!
- ceres::Solver::Options options;
- options.minimizer_progress_to_stdout = true;
- options.gradient_tolerance = 1e-12;
- options.function_tolerance = 1e-16;
- options.parameter_tolerance = 1e-12;
- ceres::Solver::Summary summary;
- Solve(options, &problem, &summary);
- LOG(INFO) << summary.FullReport();
-
- LOG(INFO) << "Nominal initial_orientation "
- << nominal_initial_orientation.coeffs().transpose();
- LOG(INFO) << "Nominal imu_to_camera "
- << nominal_imu_to_camera.coeffs().transpose();
-
- LOG(INFO) << "initial_orientation "
- << initial_orientation.coeffs().transpose();
- LOG(INFO) << "imu_to_camera " << imu_to_camera.coeffs().transpose();
- LOG(INFO) << "imu_to_camera(rotation) "
- << frc971::controls::ToRotationVectorFromQuaternion(imu_to_camera)
- .transpose();
- LOG(INFO) << "imu_to_camera delta "
- << frc971::controls::ToRotationVectorFromQuaternion(
- imu_to_camera * nominal_imu_to_camera.inverse())
- .transpose();
- LOG(INFO) << "gyro_bias " << gyro_bias.transpose();
- LOG(INFO) << "board_to_world " << board_to_world.coeffs().transpose();
- LOG(INFO) << "board_to_world(rotation) "
- << frc971::controls::ToRotationVectorFromQuaternion(
- board_to_world)
- .transpose();
- LOG(INFO) << "board_to_world delta "
- << frc971::controls::ToRotationVectorFromQuaternion(
- board_to_world * nominal_board_to_world.inverse())
- .transpose();
- LOG(INFO) << "imu_to_camera_translation "
- << imu_to_camera_translation.transpose();
- LOG(INFO) << "gravity " << kGravity * gravity_scalar;
- LOG(INFO) << "accelerometer bias " << accelerometer_bias.transpose();
- }
-
- {
- PoseFilter filter(initial_orientation, imu_to_camera, gyro_bias,
- initial_state, board_to_world, imu_to_camera_translation,
- gravity_scalar, accelerometer_bias);
- data.ReviewData(&filter);
- if (FLAGS_plot) {
- filter.Plot();
- }
+ if (FLAGS_plot) {
+ Plot(data, calibration_parameters);
}
}