Glossary

Quick reference for key terms used throughout this documentation.

A — E

Annotation: The process of applying labels to frames in a dataset. Also refers to the resulting labeled data.
Annotation Settings: Per-project (or per-dataset) configuration for the labeling interface: playback FPS, step size, and auto-save preferences.
Auto-Advance Mode: A labeling mode where the interface automatically moves to the next frame (by the configured step size) after a label is applied.
Column Mapping: The configuration that maps CSV column names to robot parameters (joint angles, end-effector coordinates).
CSV (Comma-Separated Values): The primary data format for uploading trajectory data. Each row is a frame; each column is a measurement.
Dataset: A single uploaded CSV file within a project, containing trajectory frames and (optionally) a paired video.
DH Parameters (Denavit-Hartenberg): A set of four parameters (d, theta, a, alpha) that define the geometry between consecutive joints in a robot arm. Used for forward kinematics in the generic arm configuration.
End-Effector: The tool or gripper at the tip of a robot arm. Its position is typically described by X, Y, Z coordinates.
Export Value: The string that represents a label in the exported CSV file. Can differ from the display name (e.g., display "Reach" → export "0").

Forward Kinematics: The mathematical process of computing the position of each link and the end-effector from joint angles. Used to render the 3D robot model.
FPS (Frames Per Second): The playback speed in the labeling interface. Default is 10 FPS. Also auto-detected from timestamp columns during upload.
Frame: A single row in the CSV dataset — one timestep in the trajectory. Each frame can have zero or more labels applied.
Frame Labels: The set of labels applied to a specific frame. Stored as a mapping from frame index to an array of label IDs.
Joint Angle: The rotation value of a robot joint, measured in radians. Each joint in the robot arm has one angle per frame.
Keyframe Mode: A labeling mode where you place anchor points at key frames and the system interpolates labels between them.
Label: A named annotation category (e.g., "reach", "grasp", "pour") with a color, keyboard shortcut, and export value.
Label Schema: The complete set of labels defined at the project level. All datasets in a project share the same schema.
Label Template: A saved, reusable label schema that can be imported into any project. Templates are stored per-user.
Link Length: The physical length of a segment between two joints in a robot arm. Used for 3D rendering of generic arm configurations.

Multi-Label: The ability to apply multiple labels to a single frame simultaneously (e.g., a frame can be both "grasp" and "contact").
Organization: The top-level container that groups projects. Owned by the user who created it.
Project: A collection within an organization containing datasets, a robot configuration, and a label schema.
Range Mode: A labeling mode where you select a start and end frame, then apply a label to all frames in that range at once.
Robot Configuration: The settings that define how the 3D viewer renders your robot: type, joint parameters, column mappings, and visualization options.
Rotation Axis: The axis (X, Y, or Z) around which a specific joint rotates. Configured per-joint for generic arm models.

Single Mode: The default labeling mode. Toggle labels on the current frame without automatic navigation — you control when to move to the next frame.
Step Size: The number of frames to advance when pressing arrow keys or in Auto-Advance mode. Default is 1 (frame-by-frame).
Sync Offset: The time offset (in milliseconds) between the CSV data and the paired video. Adjust this when video and trajectory data don't start at the same moment.
Timeline: The visual representation of all frames in a dataset, showing labeled regions as colored segments. Allows scrubbing to any position.
Trajectory: A sequence of robot states (joint angles + end-effector positions) over time, stored as rows in a CSV file.
URDF (Unified Robot Description Format): An XML-based file format describing a robot's physical structure (links, joints, meshes). Master Annotator supports pre-built URDF models for common robot arms.