The OD (Origin-Destination) Matrix was designed to analyze and visualize how objects move between defined zones within a monitored scene. It enabled measurement of traffic flow between specific areas by tracking movements from one zone (origin) to another (destination). The results were displayed in a matrix format, showing the number of movements for each origin-destination pair.
Configuring the OD Matrix
While simple OD Matrices can be configured within a single camera view, more typical scenarios require multi-camera setups. In FLOW, this is enabled through a Cube: a type of analytic that fuses trajectories from multiple cameras into one common reference frame. The process involves georeferencing each camera, aligning their views using tie points and a shared reference image, and connecting fragmented trajectories via re-identification rules.
Although powerful, this approach requires careful setup and calibration. For a step-by-step tutorial, refer to the article Multi-camera tracking in FLOW.
Replacement by Movement Set Statistics
The OD Matrix widget has been fully replaced and expanded by the Movement Set Statistics widget from v1.19. Movement Set Statistics provide broader capabilities, allowing more flexible definitions of movements, advanced statistical calculations, and extended configuration options suitable even for complex traffic scenarios. Without the need for georeferencing steps, this feature is an advanced evolution of the OD Matrix widget.
Refer to the Movement Set Statistics article for guidance or more information about the new approach.
What Next?
Learn more about widgets and sinks in FLOW, explore time processing, or check out other widget types such as Statistical Value and Movement Set Statistics. Use the FLOW Public API to access data from widgets and sinks and integrate it with your external systems.
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