off_test

Synchronized recordings from three sensors on one rig: a Prophesee EVK4 (IMX636) event camera, a FLIR Blackfly S Firefly frame camera, and an Intel RealSense D455 (color + depth). All three are captured on a single host per recording, so every timestamp within one trajectory shares one clock -- no cross-sensor sync step is needed, just match by nearest timestamp.

This dataset accumulates multiple recording sessions ("trajectories"), each with its own full set of sensor streams. Modality is the Hub config; trajectory is the split within it -- not every trajectory necessarily has every modality (a sensor can be off/disconnected for a given recording), so not every config has every split. See the table below for exactly which trajectory has which modalities.

Trajectories

trajectory	events	firefly	realsense_color	realsense_depth
trajectory_001	442,986,965	420	—	—
trajectory_002	—	—	151	158
trajectory_003	1,350,684,260	459	172	178

(— means that sensor recorded no data for that trajectory; counts are event rows / image frames)

Configs / how to load

from datasets import load_dataset

# one trajectory, one modality:
events = load_dataset("r3m3c3/off_test", "events", split="trajectory_001")
firefly = load_dataset("r3m3c3/off_test", "firefly", split="trajectory_001")
rs_color = load_dataset("r3m3c3/off_test", "realsense_color", split="trajectory_001")
rs_depth = load_dataset("r3m3c3/off_test", "realsense_depth", split="trajectory_001")

# ALL trajectories for one modality, as a DatasetDict keyed by trajectory:
all_events = load_dataset("r3m3c3/off_test", "events")
print(list(all_events.keys()))   # every trajectory that has event data

Each image config yields rows with a decoded PIL image column plus a timestamp_ns column. events yields a flat table (Arrow/Parquet-backed) with one row per event.

Timestamps

Every timestamp -- events' t column and every image config's timestamp_ns column -- is an int64 nanosecond Unix epoch timestamp, consistent within a trajectory (same recording host, same clock, no NTP/PTP sync needed) but not comparable across trajectories -- each recording session starts its own clock reference. To align modalities, find the nearest timestamp within the same trajectory/split only.

Event timestamps: the sensor's own internal clock is a free-running counter with no absolute epoch reference of its own. Each trajectory anchors it to epoch time independently, via an offset confirmed stable across two consecutive event packets at the start of that trajectory's recording (guards against a stale/buffered backlog burst on the first packet -- see bag_to_dataset/convert.py). Events' relative timing to each other is exact (decoded bit-for-bit from the sensor's raw EVT3 stream); the absolute anchor is accurate to within one packet's capture latency (a few milliseconds), the same order of uncertainty the other sensors' own timestamps carry.

Minimal example: events around a given frame

import numpy as np
from datasets import load_dataset

events = load_dataset("r3m3c3/off_test", "events", split="trajectory_001")
frames = load_dataset("r3m3c3/off_test", "firefly", split="trajectory_001")

t0 = frames[100]["timestamp_ns"]
t_col = np.asarray(events["t"])           # loads the t column as one array
lo, hi = np.searchsorted(t_col, [t0 - 10_000_000, t0 + 10_000_000])  # +/- 10ms
window = events[lo:hi]                     # dict of x, y, p, t lists for that window

(works the same for any other trajectory -- swap the split name)

Calibration

See calibration/<trajectory_id>.yaml for that trajectory's per-camera intrinsics (K, D, R, P) -- kept per-trajectory rather than shared, in case the rig gets recalibrated between recording sessions. Each entry has a source field -- either ros_camera_info (published live by the driver) or supplement:... (the driver didn't publish real intrinsics; filled in from a separate calibration pass instead). Check this before trusting a camera's numbers.

Sensors

sensor	model	modality
events	Prophesee EVK4 (IMX636)	event stream (EVT3)
firefly	FLIR Blackfly S BFS-U3-63S4C	RGB frames (debayered)
realsense_color	Intel RealSense D455	RGB frames
realsense_depth	Intel RealSense D455	depth (16-bit, aligned to color)