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t/slam: Cache tracked pose timestamp

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This is mainly to avoid problems with filters that calculate
their dt from previous calls. In particular the one euro filter fix
that gets implemented in the next commit would crash because of dt=0.
This commit is contained in:
Mateo de Mayo 2022-02-14 16:32:20 -03:00 committed by Jakob Bornecrantz
parent b04c26e522
commit 17dee2bb68
1 changed files with 18 additions and 1 deletions
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19
src/xrt/auxiliary/tracking/t_tracker_slam.cpp
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@ -217,6 +217,9 @@ struct TrackerSlam
//! @todo Should be automatically computed instead of required to be filled manually through the UI.
xrt_vec3 gravity_correction{0, 0, -MATH_GRAVITY_M_S2};
struct xrt_space_relation last_rel = XRT_SPACE_RELATION_ZERO; //!< Last reported/tracked pose
timepoint_ns last_ts; //!< Last reported/tracked pose timestamp
//! Filters are used to smooth out the resulting trajectory
struct
{
@ -358,7 +361,7 @@ filter_pose(TrackerSlam &t, timepoint_ns when_ns, struct xrt_space_relation *out
}
if (out_relation->relation_flags & XRT_SPACE_RELATION_ORIENTATION_VALID_BIT) {
// Don't save w component as we can retrieve it knowing these are unit quaternions
// Don't save w component as we can retrieve it knowing these are (almost) unit quaternions
xrt_vec3 rot = {out_relation->pose.orientation.x, out_relation->pose.orientation.y,
out_relation->pose.orientation.z};
m_ff_vec3_f32_push(t.filter.rot_ff, &rot, when_ns);
@ -371,9 +374,14 @@ filter_pose(TrackerSlam &t, timepoint_ns when_ns, struct xrt_space_relation *out
xrt_vec3 avg_rot; // Naive but good enough rotation average
m_ff_vec3_f32_filter(t.filter.rot_ff, when_ns - window, when_ns, &avg_rot);
// Considering the naive averaging this W is a bit wrong, but it feels reasonably well
float avg_rot_w = sqrtf(1 - (avg_rot.x * avg_rot.x + avg_rot.y * avg_rot.y + avg_rot.z * avg_rot.z));
out_relation->pose.orientation = xrt_quat{avg_rot.x, avg_rot.y, avg_rot.z, avg_rot_w};
out_relation->pose.position = avg_pos;
//! @todo Implement the quaternion averaging with a m_ff_vec4_f32 and
//! normalization. Although it would be best to have a way of generalizing
//! types before so as to not have redundant copies of ff logic.
}
if (t.filter.use_exponential_smoothing_filter) {
@ -400,9 +408,18 @@ extern "C" void
t_slam_get_tracked_pose(struct xrt_tracked_slam *xts, timepoint_ns when_ns, struct xrt_space_relation *out_relation)
{
auto &t = *container_of(xts, TrackerSlam, base);
if (when_ns == t.last_ts) {
*out_relation = t.last_rel;
return;
}
flush_poses(t);
predict_pose(t, when_ns, out_relation);
filter_pose(t, when_ns, out_relation);
t.last_rel = *out_relation;
t.last_ts = when_ns;
}
//! Receive and send IMU samples to the external SLAM system