Speed Estimation

Estimates speeds of objects and sets triggers based on low/high thresholds.

Overview

The Speed Estimation node estimates speeds of objects in a ROI and sets triggers based on low/high thresholds. This node makes it easy to build common use cases such as No running zones, traffic jams, etc.

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

Inputs & Outputs

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

Properties

Property

Value

rois

Semicolon separated list of areas in the video within which the Proximity Detector tracks these objects.

If none is specified, the Proximity Detector tracks objects within the entire frame.

Format: left1,top1,right1,bottom1; left2,top2,right2,bottom2

Ex: 10,10,100,100; 200,200,300,300

roi_labels

Comma separated list of labels for each ROI in the rois list above.

Format: label1, label2

Ex: door, window

object_types

Comma separated list of object types to measure speed.

Ex. car,person

Accepted formats:
object_label: any object of this type, with or without a classifier attribute. Example: car

object_label.class_type: any object of this type that has a specific classifier attribute. Example: car.red

object_label.*: any object of this type that has at least one classifier attribute. Example: car.* (this will match car.red, car.yellow, etc)

miles_per_pixel

Approximate number of miles per pixel. Obtain by dividing image width by the number of miles between left and right ends of the view.

Ex. 0.0004

speed_trigger_threshold_high_mph

Set a trigger when speed exceeds the high threshold..

Ex. 20

speed_trigger_threshold_low_mph

Set a trigger when speed is below the low threshold.

Ex. 2

display_objects_mode

Display objects that meet this criteria on the video

Options:

  • none : None
  • triggered : Only those above or below the thresholds.
  • all : All

display_roi

If true, ROI will be drawn on video

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 Speed Estimation Nodes is of the form annotate_speedX (ex. annotate_speed1)

Example

"nodes": {
    "annotate_speed1": {
        "type": "annotate_speed",
        "rois": {
            "<roi_label>": {
                "coords": [[<point1_x>, <point1_y>], 
                           [<point2_x>, <point2_y>], 
                           [<point3_x>, <point3_y>]],
                "average_speed": <int>,
                "objects_low_speed_count": <int>,
                "objects_low_speed_delta": <int>,
                "objects_medium_speed_count": <int>,
                "objects_medium_speed_delta": <int>,
                "objects_high_speed_count": <int>,
                "objects_high_speed_delta": <int>,                 
                "objects_low_speed": [object_id1, object_id2...],
                "objects_medium_speed": [object_id1, object_id2...],
                "objects_high_speed": [object_id1, object_id2...]
            }
        }
    }
}

Format

Key

Type

Description

<roi_label>

Array of dictionaries

Contains information about this specific ROI

<roi_label>.coords

Array of Arrays

Contains the bounding box coordinates that represent this ROI

<roi_label>.objects_low_speed_count

Integer

Number of objects currently in this ROI below thespeed_trigger_threshold_low_mph

<roi_label>.objects_low_speed_delta

Integer

Number of new objects in the ROI whose speed was below speed_trigger_threshold_low_mph between last frame and this frame

<roi_label>.objects_medium_speed_count

Integer

Number of objects currently in this ROI between thespeed_trigger_threshold_low_mph and speed_trigger_threshold_high_mph

<roi_label>.objects_medium_speed_delta

Integer

Number of new objects in the ROI whose speed was between speed_trigger_threshold_low_mph and speed_trigger_threshold_high_mph between last frame and this frame

<roi_label>.objects_high_speed_count

Integer

Number of objects currently in this ROI above thespeed_trigger_threshold_high_mph

<roi_label>.objects_high_speed_delta

Integer

Number of new objects in the ROI whose speed was above speed_trigger_threshold_high_mph between last frame and this frame

<roi_label>.objects_low_speed

List of long integers

List of object IDs of low speed objects

<roi_label>.objects_medium_speed

List of long integers

List of object IDs of medium speed objects

<roi_label>.objects_high_speed

List of long integers

List of object IDs of high speed objects


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