This article will take you through how to trigger a NTCIP call when the number of pedestrians in the crosswalk meets and/or exceeds a specified value. If you would like to trigger a NTCIP call when any number of pedestrians are in the crosswalk, see this sample NTCIP configuration guide instead.

 

Sample Presence Event JSON:

{
    "imageSize": {
        "x": 1264,
        "y": 720
    },
    "objectType": "car",
    "sensorData": {
        "active": true,
        "numObjectsInRegion": 3,
        "object": {
            "confidence": 0.67083024978637695,
            "enteredOn": 1632237441457,
            "inferenceConfidence": -0.10000000149011612,
            "objectType": "car",
            "trackerConfidence": 0.67083024978637695,
            "uniqueId": 13260042503639269394
        },
        "startOn": 1632237440818
    },
    "sensorName": "PRESENCE_CAR_1",
    "sensorType": "presence",
    "streamId": "0",
    "timecollected": "2021-09-21 15:17:21.458",
    "uniqueId": "80e5171f-0a2f-43e2-9072-70055dc1d310",
    "version": 2
}

Instructions

First, ensure that there is a presence sensor monitoring the crosswalk of interest. Note the presence sensor name (i.e. PRESENCE_PERSON_1) that you would like to have trigger the NTCIP calls.

 

 

Next, follow the instructions at this Knowledge Base article to configure NTCIP calls on entry/exit into the presence sensor. 

 

Now, to modify the entry NTCIP call so that it is only triggered when a certain number (or more) of pedestrians are present, add an additional sensorData filter per the guidelines below:

 

for numObjectsInRegion value < 10:

[X-9] : any number X and above, until 9

[1-9]\d{1,} : any number 10 and above

 

regex = [X-9]|[1-9]\d{1,}

 

Example: 

trigger whenever numObjectsInRegion >= 4, add sensorData filter:

 

Regex for numObjectsInRegion value >= 10, (and <100):

X : first digit of value (i.e. value=28, X=2)

Y : second digit of value (i.e. value=28, Y=8)

Z = X+1

regex = [X-9][Y-9]|[Z-9]\d{1,}

 

Example: 

trigger whenever numObjectsInRegion >= 12, add sensorData filter: