metadata/schema.md

Metadata Schema

All timestamps use nanoseconds (ns). The first version stores indexes only. Raw ROSBag files remain the source of truth.

metadata/sessions.parquet

Column	Type	Description
session_id	string	Session directory name.
bag_path	string	Relative path to bag.bag.
sha256_path	string	Relative path to bag.bag.sha256.
metadata_path	string	Relative path to metadata.yaml.
bag_size_bytes	int64	Raw ROSBag file size in bytes.
duration_sec	float64	Bag duration in seconds.
start_time_ns	int64	Earliest message timestamp.
end_time_ns	int64	Latest message timestamp.
num_messages	int64	Total message count.
has_lidar	bool	Session contains lidar data.
has_rgb	bool	Session contains RGB camera data.
has_depth	bool	Session contains depth camera data.
has_infra	bool	Session contains infrared camera data.
has_tof	bool	Session contains ToF data.
has_imu	bool	Session contains IMU data.
has_odom	bool	Session contains odometry data.
has_tf	bool	Session contains TF data.
calibration_id	string	Calibration directory ID.
quality_status	string	One of unchecked, good, usable, bad.
source_filename	string	Original bag filename.
import_mode	string	Import mode: hardlink, copy, symlink, or move.

metadata/topics.parquet

Column	Type	Description
session_id	string	Session directory name.
bag_path	string	Relative path to bag.bag.
topic	string	ROS topic name.
msg_type	string	ROS message type.
count	int64	Message count for this topic.
hz_mean	float64	Mean frequency estimated from timestamps.
timestamp_min_ns	int64	Earliest topic timestamp.
timestamp_max_ns	int64	Latest topic timestamp.
category	string	Topic category.

metadata/tof_sensor.yaml

Machine-readable metadata for the ToF sensor used by /nlink_tofsensem_cascade.

Key facts:

Field	Description
model	Nooploop TOFSense-M.
collection_configuration	Six-node UART query cascade in 8x8 mode.
message_layout	ROS message and per-node/per-pixel fields.
distance_status_codes	Meaning of dis_status values.
specifications	Range, FOV, refresh rate, laser class, power, and interface limits.

See metadata/tof_sensor.md for the human-readable version.