Glossary

This section provides meanings and definitions for terms that one may find in Prophesee documentations.

Generic terms

Term

Definition

Meaning

AER

Address-Event Representation

Transmission protocol for event-based data. An “event” is a data packet containing

the pixel’s address in the array plus a payload, e.g. contrast detection polarity

AFK

Anti FlicKer

Technique allowing to remove flickering events (in SW or HW)

APS event

Active Pixel Sensor

Deprecated name for EM event

ATIS

Asynchronous Time-based

Image Sensor

Name for Prophesee’s family of frame-free contrast-triggered pixel-individually

auto-sampling image sensors with time-domain intensity encoding

Biases

Set of settings allowing to control Prophesee sensors (e.g. their sensitivity,

bandwidth, etc)

CD event

Contrast Detection

Indicates an “event” triggered by temporal contrast (relative intensity change).

CD events have a polarity, negative or positive (CD ON or CD OFF),

depending on if triggered by decreasing or increasing light intensity

Crazy Pixel

Pixel generating spontaneous background activity; data from crazy pixels can be

removed with filtering algorithms (e.g. STC filter)

DSP

Digital Signal Processor

Specialized microprocessor chip, with its architecture optimized for the

operational needs of digital signal processing.

EM event

Exposure Measurement

Event-based gray-level data representation using time-domain encoding of the

intensity information

EPS

Events Per Second

Readout Speed. For example, EPSMAX - Maximum throughput (Events per second, EPS)

of the event readout system

ERC

Event Rate Control

Technique used to control the maximum event rate of a sensor

ESP

Event Signal Processing

Specialized microprocessor chip, with its architecture optimized for the

operational needs of event signal processing.

Event

Sensor-generated data packet containing the pixel’s address in the array, a

payload (e.g. contrast detection polarity), and a timestamp

EVK

Evaluation Kit

Prophesee camera with the capability to visualize, record and process data on a PC

EVT

Event Type Definition

Prophesee event-based Processing Systems gather data from the sensor and encode

these data in a proprietary event stream format.

This event format has been specified to strike a balance between compactness and robustness.

FOV

Field Of View

Area that can be seen by the camera with its optics at the given position

Latency

Delay of response for a pixel. It is the time between a stimulus light event seen

by a CD pixel and the related event’s timestamp. This term should not be confused

with the timestamp resolution. Typical values for our last generation of sensor

is a latency of 100us and a temporal resolution of 1us.

MIPI

Mobile Industry Processor Interface

Interface supported by some of Prophesee products and sensors

NCT

Nominal Contrast Threshold

Contrast at 10 lux with response probability higher than 0.5

ONBOARD

Prophesee Reference System (deprecated), an embedded solution that combines

Prophesee sensor and computer vision products on a single board computer platform

Metavision Designer

Prophesee software allowing engineers to interconnect components very easily for

fast prototyping of event-based vision applications

Metavision HAL

Hardware Abstraction Layer

Prophesee software aimed at controlling Prophesee event-based cameras and acquiring data

Metavision Studio

Application with GUI allowing to visualize and record data from

event-based sensors and also read already recorded data (e.g. datasets)

Metavision SDK

Prophesee C++ SDK allowing to process event-based data. High-performance

algorithms are available via APIs, ready to go to production with event-based

Vision applications

Polarity

Property of a CD event that can be negative or positive (CD ON or CD OFF)

depending on if triggered by decreasing or increasing light

PSM

Particle Size Measurement

Application aimed at measuring size of particles

ROI

Region of Interest

Part of the sensor still active while other pixels are kept in reset, to focus on

specific parts of the scene

SoC

System on Chip

Integrated circuit that takes a single platform and integrates an entire

electronic or computer system onto it (CPU with additional features, like HW accelerators)

TD event

Temporal Difference

Deprecated name for CD events

Timestamp

Time of event generation by Prophesee sensor, in microsecond precision

Trigger

Input or output signals (Trigger In or Out) allowing to control the sensor and

synchronize data between several devices

VCEB

VisionCam Event-Based

Imago technologies reference system using Prophesee sensor

XYT view

X-Y-Time view

3D representation of events data in X-Y-Time space

SW-specific terms

Term

Definition

Meaning

Application

Software tool aimed at solving specific needs (e.g. focusing, calibration, data

conversion, etc); it is delivered as pre-compiled binaries and ready for execution

Asynchronous algorithm

Algorithm processing time slices of fixed duration and allowing to retrieve an

outcome at a fixed refresh rate rather than for each processed buffer of events

IOU

Intersection over Union

Evaluation metric used to measure the accuracy of an object detector on a particular dataset

NMS

Non Maximum Suppression

Class of algorithms used in computer vision to select one entity

(e.g. bounding boxes) out of many overlapping entities

Pipeline

Class aimed at simplifying the writing of algorithms; it processes data as a

pipeline of processing units (stages) and controls their execution

Pipeline stage

Processing unit (stage) in a pipeline; each processing stage can have previous

stages and next stages, thus forming a directed graph

ROS

Robot Operating System

Set of software libraries and tools that help to build robot applications

Sample

Code example aimed at demonstrating a concept as simple as possible, it serves as

a tutorial and delivered as source code

STC filter

Spacial Temporal Contrast

Data filtering algorithm aimed to remove noisy data based on spatio-temporal

consistency (presence of other events in space and time)

Synchronous algorithm

Algorithm directly processing each received buffer of events and generating an

outcome for each processed buffer

Trail Filter

Data filtering algorithm aimed at filtering events at a pixel level where all

events following the first event for the same pixel are discarded