Asynchronous Queries

Groundlight provides a simple interface for submitting asynchronous queries. This is useful for times in which the thread or process or machine submitting image queries is not the same thread or machine that will be retrieving and using the results. For example, you might have a forward deployed robot or camera that submits image queries to Groundlight, and a separate server that retrieves the results and takes action based on them. We will refer to these two machines as the submitting machine and the retrieving machine.

Setup Submitting Machine

On the submitting machine, you will need to install the Groundlight Python SDK. Then you can submit image queries asynchronously using the ask_async interface (read the full documentation here). ask_async submits your query and returns as soon as the query is submitted. It does not wait for an answer to be available prior to returning to minimize the time your program spends interacting with Groundlight. As a result, the ImageQuery object ask_async returns lacks a result (the result field will be None). This is acceptable for this use case as the submitting machine is not interested in the result. Instead, the submitting machine just needs to communicate the ImageQuery.ids to the retrieving machine - this might be done via a database, a message queue, or some other mechanism. For this example, we assume you are using a database where you save the ImageQuery.id to it via db.save(image_query.id).

from groundlight import Groundlight
import cv2
from time import sleep

detector = gl.get_or_create_detector(name="your_detector_name", query="your_query")

cam = cv2.VideoCapture(0)  # Initialize camera (0 is the default index)

while True:
    _, image = cam.read()  # Capture one frame from the camera
    image_query = gl.ask_async(detector=detector, image=image)  # Submit the frame to Groundlight
    db.save(image_query.id)  # Save the image_query.id to a database for the retrieving machine to use
    sleep(10) # Sleep for 10 seconds before submitting the next query

cam.release()  # Release the camera

Setup Retrieving Machine

On the retrieving machine you will need to install the Groundlight Python SDK. Then you can retrieve the results of the image queries submitted by another machine using get_image_query. The retrieving machine can then use the ImageQuery.result to take action based on the result for whatever application you are building. For this example, we assume your application looks up the next image query to process from a database via db.get_next_image_query_id() and that this function returns None once all ImageQuerys are processed.

from groundlight import Groundlight

detector = gl.get_or_create_detector(name="your_detector_name", query="your_query")

image_query_id = db.get_next_image_query_id()

while image_query_id is not None:
    image_query = gl.get_image_query(id=image_query_id) # retrieve the image query from Groundlight
    result = image_query.result

    # take action based on the result of the image query
    if result.label == 'YES':
        pass # TODO: do something based on your application
    elif result.label == 'NO':
        pass # TODO: do something based on your application
    elif result.label == 'UNCLEAR':
        pass # TODO: do something based on your application

    # update image_query_id for next iteration of the loop
    image_query_id = db.get_next_image_query_id()

Important Considerations

When you submit an image query asynchronously, ML prediction on your query is not instant. So attempting to retrieve the result immediately after submitting an async query will likely result in an UNCLEAR result as Groundlight is still processing your query. Instead, if your code needs a result synchronously we recommend using one of our methods with a polling mechanism to retrieve the result. You can see all of the interfaces available in the documentation here.

from groundlight import Groundlight
from PIL import Image

detector = gl.get_or_create_detector(name="your_detector_name", query="your_query")
image = Image.open("/path/to/your/image.jpg")
image_query = gl.ask_async(detector=detector, image=image)  # Submit async query to Groundlight
result = image_query.result  # This will always be 'None' as you asked asynchronously

image_query = gl.get_image_query(id=image_query.id)  # Immediately retrieve the image query from Groundlight
result = image_query.result  # This will likely be 'UNCLEAR' as Groundlight is still processing your query

image_query = gl.wait_for_confident_result(id=image_query.id)  # Poll for a confident result from Groundlight
result = image_query.result