Device Queue Event

1#!/usr/bin/env python3
2
3"""
4 This example demonstrates use of queue events to block a thread until a message
5 arrives to any (of the specified) queue
6"""
7
8import cv2
9import depthai as dai
10
11# Create pipeline
12pipeline = dai.Pipeline()
13
14# Define sources and outputs
15camRgb = pipeline.create(dai.node.ColorCamera)
16camMono = pipeline.create(dai.node.MonoCamera)
17xoutRgb = pipeline.create(dai.node.XLinkOut)
18xoutMono = pipeline.create(dai.node.XLinkOut)
19
20xoutRgb.setStreamName("rgb")
21xoutMono.setStreamName("mono")
22
23# Properties
24camRgb.setInterleaved(True)
25camRgb.setPreviewSize(300, 300)
26
27# Linking
28camRgb.preview.link(xoutRgb.input)
29camMono.out.link(xoutMono.input)
30
31# Connect to device and start pipeline
32with dai.Device(pipeline) as device:
33
34    # Clear queue events
35    device.getQueueEvents()
36
37    while True:
38        # Block until a message arrives to any of the specified queues
39        queueName = device.getQueueEvent(("rgb", "mono"))
40
41        # Getting that message from queue with name specified by the event
42        # Note: number of events doesn't necessarily match number of messages in queues
43        # because queues can be set to non-blocking (overwriting) behavior
44        message = device.getOutputQueue(queueName).get()
45
46        # Display arrived frames
47        if type(message) == dai.ImgFrame:
48            cv2.imshow(queueName, message.getCvFrame())
49
50        if cv2.waitKey(1) == ord('q'):
51            break