Overview

The Object Flow Counter node provides a breakdown of specific object types that cross a line or a sequence of lines defined by a Line Crossing Counter node prior to it. This node makes it easy to build common use cases such as People flow mapping in retail environments, Traffic intersection analysis, etc.

This node requires a Line Crossing Counter before it in order to function properly.

Inputs & Outputs

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

Properties

Property	Description	Type	Default	Required
`object_types`	Comma-separated list of object types to consider. Empty list processes all objects. ex. `car, person, face.mask`	model-label	null	Yes
`object_flow_rules`	Comma-separated list of labels of lines or line pairs (optionally with `:dir1` or `:dir2` suffix) or directions (`dir1`, `dir2`) that an object must cross through to be counted. ex. `line_freeway_exit, line_streetA_EB+line_streetB_NB, line_streetA:dir1+line_streetB:dir2`. If empty, counts crossings through each line.	string	null	No
`line_distance`	Distance between the two lines used to estimate speed for line-pair rules. When provided, the node outputs speed metadata for `lineA+lineB` style rules and shows speed in the ticker for those rules.	float	null	No
`line_distance_unit`	Unit for `line_distance`. Supported values: `feet`, `meters`. `feet` outputs speeds in `mph`; `meters` outputs speeds in `kmph`.	enum	feet	No
`reset_trigger`	Reset object counts when this condition evaluates to true. ex. `nodes.time_trigger1.triggered`. Use it in combination with a Time Trigger to accumulate statistics over a regular interval like 5 minutes.	trigger-condition	null	No
`display`	Display options. Values: `none`, `basic`	enum	basic	No

Metadata

Metadata Property	Description
`nodes.<node_id>`	Describes the Lines monitored by this node, and their properties. Format : as defined in the table below. `<node_id>` for Object Flow Nodes is of the form `object_flowX` (ex. `object_flow1`)

Example

"nodes": {
    "object_flow1": {
        "type": "object_flow",
        "total_objects_crossed_count": <number>,
        "total_objects_crossed_delta": <number>
        "lines": {
            "<line_rule>": {
                "total_objects_crossed_count": <number>,
                "total_objects_crossed_delta": <number>,
                "object_crossed_counts": {
                    "<object_label1>": <number>,
                    ...
                },
                "object_crossed_deltas": {
                    "<object_label1>": <number>,
                    ...
                },
                "crossed_objects": [ <object_tracking_id>,<object_tracking_id> ],
                "object_speeds_min": {
                    "<object_label1>": <number|null>,
                    ...
                },
                "object_speeds_max": {
                    "<object_label1>": <number|null>,
                    ...
                },
                "object_speeds_avg": {
                    "<object_label1>": <number|null>,
                    ...
                },
                "speed_unit": "<mph|kmph>"
            }
        }
    }
}

Format

Key	Type	Description
`total_objects_crossed_count`	Integer	Number of objects seen crossing all monitored rules since last time stats were reset
`total_objects_crossed_delta`	Integer	Number of objects seen crossing all monitored rules between last frame and this frame
`<line_rule>`	Dictionary	Contains information about this specific object flow rule (specific line or sequence of lines)
`<line_label>.total_objects_crossed_count`	Integer	Number of objects seen crossing this rule since the last time stats were reset
`<line_label>.total_objects_crossed_delta`	Integer	Number of objects seen crossing this rule between last frame and this frame
`<line_label>.object_crossed_counts`	Dictionary	Dictionary containing object crossing count accumulated since last time stats were reset
`<line_label>.object_crossed_counts.<object_label>`	Integer	Number of objects of this label seen crossing this rule since the last time stats were reset
`<line_label>.object_crossed_deltas`	Integer	Dictionary containing object crossing change from last frame to this frame
`<line_label>.object_crossed_deltas.<object_label>`	Integer	Number of objects of this label seen crossing this line between last frame and this frame
`<line_label>.crossed_objects`	List of object IDs	Information about the objects currently crossing the rule. `object_tracking_id` : Unique identifier for a specific object, as specified by `object.id` property (see AI Model Node )
`<line_label>.object_speeds_min`	Dictionary	Minimum observed speed per object label for this rule. Keys are always present for tracked labels; value is `null` until a speed is available. Only meaningful for line-pair rules when `line_distance` is set.
`<line_label>.object_speeds_max`	Dictionary	Maximum observed speed per object label for this rule. Keys are always present for tracked labels; value is `null` until a speed is available. Only meaningful for line-pair rules when `line_distance` is set.
`<line_label>.object_speeds_avg`	Dictionary	Average observed speed per object label for this rule. Keys are always present for tracked labels; value is `null` until a speed is available. Only meaningful for line-pair rules when `line_distance` is set.
`<line_label>.speed_unit`	String	Speed unit for this node: `mph` when `line_distance_unit=feet`, `kmph` when `line_distance_unit=meters`.