Overview

The Presence Monitor node tracks how long each detected, tracked object has been present in the specified region in the video, can highlight objects and generate max time/occupancy level alarms, and adds the presence metadata to the frame metadata. It is designed for monitoring use cases.

This node generates presence metrics: current occupancy, objects above max time threshold, occupancy above/below max thresholds.

This node requires a AI Model Node and a Track Objects Node before it in order to function properly.

This node is a simplified version of the Occupancy Monitor. Use the Occupancy monitor if you need to collect statistics such as wait times, people flow, etc. for dashboards, reporting and business intelligence.

Inputs & Outputs

Inputs : 1, Media Format : Raw Video
Outputs : 1, Media Format: Raw Video
Output Metadata : Presence Information

Properties

Property	Description	Type	Default	Required
`roi_labels`	Regions of interest labels. Conditional on `rois`.	hidden	-	Yes
`rois`	Regions of interest. Conditional on `roi_labels`. Format: `x1,y1,x2,y2,x3,y3; X1,Y1,X2,Y2,X3,Y3,X4,Y4`.	polygon	null	Yes
`objects_to_track`	Comma separated list of Detected Object labels to track, as specified in Model Labels. Example: `car, person`. Accepted formats: `object_label`, `object_label.class_type`, `object_label.*`.	model-label	null	No
`min_presence_time`	Min. time an object should be present in the ROI in order to be considered present. Example: `10.0`.	float	1.0	Yes
`max_presence_time`	Create an alarm and shows an orange bounding box around object if present more than specified seconds in the ROI. Example: `20.0`.	float	null	No
`max_occupancy_threshold`	Set a trigger when number of objects in the ROI exceeds or drops below this threshold. Example: `10`.	number	null	No
`crossing_buffer`	Interval during which an object will not be repeatedly counted if it leaves and reenters the ROI. Example: `1.0`.	float	1.0	Yes
`object_types_to_flag`	Flag specific objects so you can trigger downstream events using those. Options: `current`, `entry`, `above_max_time`, `exit`.	enum-multi	null	No
`display_roi`	Display ROI?	bool	true	No
`display_roi_meta`	Display ROI Statistics? Options: `none` (Do not display), `basic` (Display Occupancy counts only), `detailed` (Display detailed statistics).	enum	detailed	No
`display_objects`	Display objects? Options: `none` (Do not display), `basic` (Tracking point only), `detailed` (Tracking point and time).	enum	detailed	No
`tracking_mode`	Tracking mode. Options: `centroid`, `top-center`, `bottom-center`, `left-center`, `right-center`.	enum	centroid	No

Metadata

Metadata Property	Description
`nodes.<node_id>`	Describes the ROIs monitored by this node, and their properties. Format : as defined in the table below. `<node_id>` for Presence monitor is of the form `annotate_presenceX` (ex. `annotate_presence1`)

Example

"nodes": {
    "annotate_presence1": {
        "type": "annotate_presence",
        "rois": {
            "<roi_label>": {
                "coords": [
                    [468, 172],
                    [597, 307],
                    [912, 206],
                    [1227, 277],
                    [1247, 135],
                    [1054, 91],
                    [946, 121],
                    [797, 87],
                    [645, 104],
                    [468, 172]
                ],
                "current_occupancy": 1,                  
                "objects_entered_delta": 0,
                "objects_exited_delta": 1,
                "objects_above_max_waiting_time_count": 1,
                "objects_above_max_waiting_time_delta": 0,
                "objects_above_max_occupancy_count": 0,
                "objects_below_max_occupancy_count": 0,
                "occupancy_above_max_threshold_delta": false,
                "occupancy_below_max_threshold_delta": false,
                "objects_flagged": ["12837198712897","1231293712897612"]                  
            }
        }
    }
}

Format

Key	Type	Description
`<roi_label>`	Array of dictionaries	Contains information about this specific ROI
`<roi_label>.coords`	Dictionary	Contains the bounding box coordinates that represent this ROI
`<roi_label>.current_occupancy`	Integer	Current number objects in ROI
`<roi_label>.objects_entered_delta`	Integer	Number of objects that entered the ROI between last frame and this frame
`<roi_label>.objects_exited_delta`	Integer	Number of objects that left the ROI between last frame and this frame
`<roi_label>.objects_above_max_waiting_time_count`	Integer	Number of objects currently inside the ROI above the specified temporal threshold
`<roi_label>.objects_above_max_waiting_time_delta`	Integer	Number of new objects that exceeded the threshold between the last frame and this frame
`<roi_label>.objects_above_max_occupancy_count`	Integer	Number of objects above the max occupancy threshold
`<roi_label>.objects_below_max_occupancy_count`	Integer	Number of objects needed to hit the max occupancy threshold
`<roi_label>.occupancy_above_max_threshold_delta`	Bool	True when the total number of objects changes to above the max occupancy threshold
`<roi_label>.occupancy_below_max_threshold_delta`	Bool	True when the total number of objects changes to below the max occupancy threshold
`<roi_label>.objects_flagged`	Array of strings	List of flagged object ids