Overview

The Scene Change Detection node keeps track of the changes in the ROI area in order to generate alarms if some anomaly is detected. It performs differentiated handling for objects types allowed to be within the ROI area bypassing the alarm in such case, and adds the OSHA analytics metadata to the frame metadata.

Inputs & Outputs

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

Properties

Property	Value
`roi_labels`	Comma separated list of labels for each ROI in the `rois` list above. Format: `label1, label2` Ex: `queue_entrance, queue_store`
`rois`	Semicolon separated list of areas in the video within which the node tracks these objects. If none is specified, the Queue Length Counter tracks objects within the entire frame. Format: `left1,top1,right1,bottom1; left2,top2,right2,bottom2` Ex: `10,10,100,100; 200,200,300,300`
`osha_compliance_type`	OSHA compliance monitoring type. `stacking` (Stacking of boxes/palettes < 7ft high) `pathway` (Pathways unblocked) `fire_extinguisher` (Fire Extinguishers unblocked) `electrical_panel` (Electrical panels unblocked) `door` (Doors unblocked) `other` (Other - Generic)
`objects_allowed`	Comma separated list of Detected Object labels to track, as specified in Model Labels ex. `car, person` Objects classes that will bypass the alarm when present in the ROIs.
`change_threshold`	Amount of change above which an alarm will be triggered for an ROI, adjusted for ROi size. Increase to reduce false alarms and reduce to detect smaller obstructions Ex. `1.5`
`alarm_buffer_seconds`	Number of seconds for which an obstruction should be detected to trigger an alarm Ex. `10`
`reference_update_interval`	When set as 0 the reference frame is just loaded in deployment initialization, else updated every X seconds if no alarm is triggered. Ex. `0`
`tracking_mode`	The point to be used as tracking point, refers to the position on the object's bounding box. `centroid` `top-center` `bottom-center` `left-center` `right-center` `all`
`display_roi`	Boolean. If true, ROI info will be drawn on video. Ex. `true` / `false`
`display_objects`	Boolean. If true, the object's info is drawn on video. Ex. `true` / `false`
`display_debug_info`	Boolean. If true, debugging information will be drawn on video for troubleshooting. Ex. `true` / `false`

Metadata

Metadata Property	Description
`nodes.<node_id>`	`<node_id>` for the Scene Change Detection is of the form `scene_change_detectionX` (ex. `scene_change_detection1`) Format : as defined in the table below.

Example

"nodes": {
    "scene_change_detection1": {
         "type": "scene_change_detection",
         "clear_rois_count": 0,
         "clear_rois_delta": 0,
         "description":"Scene Change Detection",
         "exception_alarm_rois_count": 1,
         "exception_alarm_rois_delta": 0,
         "exception_alarm_rois_ids":[
            "polygon1"
         ],
         "exception_allowed_rois_count": 0,
         "exception_allowed_rois_delta": 0,
         "exception_allowed_rois_ids": [],
         "monitoring_type": "pathway",
         "reference_image_updated": false,
         "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_objects":{
                  "1496812582445515449":{
                     "allowed": false,
                     "first_seen": 248.4,
                     "first_seen_utc": "2023-02-10T03:32:09.180692Z",
                     "time_present": 0.867
                  },
                  "1496812582445515453":{
                     "allowed": false,
                     "first_seen": 249.0,
                     "first_seen_utc": "2023-02-10T03:32:09.266444Z",
                     "time_present": 0.267
                  }
               },
               "state":"alarm",
               "time_since_last_state_change": 37.6,
               "type":"pathway",
               "change_threshold": 1.0,
               "change_score": 0.3 
            }
        }
    }
}

Format

Key	Type	Description
`clear_rois_count`	Integer	Number of ROIs that are not triggering any alarm
`clear_rois_delta`	Integer	Difference of clear ROIs between last frame and this frame
`description`	String
`exception_alarm_rois_count`	Integer	Number of ROIs that are triggering an alarm
`exception_alarm_rois_delta`	Integer	Difference of the number of ROIs creating alarm between last frame and this frame
`exception_alarm_rois_ids`	List	The IDs of the ROIs that are generating an exception alarm
`exception_allowed_rois_count`	Integer	Number of ROIs that are bypassing an alarm because there's an allowed object within the ROI area
`exception_allowed_rois_delta`	Integer	Difference of the number of ROIs bypassing alarm between last frame and this frame
`exception_allowed_rois_ids`	List	The IDs of the ROIs that are bypassing an exception alarm
`monitoring_type`	String	OSHA compliance monitoring type
`reference_image_updated`	Boolean	Set as True in the frame the reference image is updated
`<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_objects`	Array of dictionaries	Information about the objects currently in the ROI `object_tracking_id` : Unique identifier for a specific object, as specified by `object.id` property (see Model Inference Node ) `allowed`: Boolean. If the object's class is allowed or not to be within the ROI area `first_seen` : Time in seconds (since start of deployment) when the object was first seen in the ROI `first_seen_utc` : UTC time in ISO 8601 format when the object was first seen in the ROI `time_present` : Time in seconds that the object has been present in the ROI
`state`	String	The state of the ROI can be either `clear` or `alarm`
`time_since_last_state_change`	Float	The amount of seconds passed since the `state` changed
`type`	String	OSHA compliance monitoring type
`change_threshold`	Float	Amount of change above which an alarm will be triggered for an ROI
`change_score`	Float	The change score obtained from the comparison between the reference image and current frame