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  • Mono preview - Alternate between dot projector and illumination LED
  • Demo
  • Setup
  • Source code
  • Pipeline

Mono preview - Alternate between dot projector and illumination LED

This example will alternate between the IR illumination LED and IR dot projector. By default, example script will run both left and right monochrome camera sensors at 30FPS, and it will switch between the IR LED and dot projector every frame - meaning you will get LED-illuminated frames at 15FPS, and dot projector-illuminated frames at 15FPS.LED-illuminated frames can be used for your AI vision tasks and CV algorithms (eg. Feature Tracker) in low-light environments. Dot projector-illuminated frames are used for active stereo depth.

Demo

On the video, we disabled both projector and LED for about a second, just to demonstrate how the scene looks in almost-complete darkness.

Setup

Please run the install script to download all required dependencies. Please note that this script must be ran from git context, so you have to download the depthai-python repository first and then run the script
Command Line
1git clone https://github.com/luxonis/depthai-python.git
2cd depthai-python/examples
3python3 install_requirements.py
For additional information, please follow the installation guide.

Source code

Python
C++

Python

Python
GitHub
1#!/usr/bin/env python3
2
3import cv2
4import depthai as dai
5
6if 1:  # PoE config
7    fps = 30
8    res = dai.MonoCameraProperties.SensorResolution.THE_400_P
9    poolSize = 24  # default 3, increased to prevent desync
10else:  # USB
11    fps = 30
12    res = dai.MonoCameraProperties.SensorResolution.THE_720_P
13    poolSize = 8  # default 3, increased to prevent desync
14
15# Create pipeline
16pipeline = dai.Pipeline()
17
18# Define sources and outputs
19monoL = pipeline.create(dai.node.MonoCamera)
20monoR = pipeline.create(dai.node.MonoCamera)
21
22monoL.setCamera("left")
23monoL.setResolution(res)
24monoL.setFps(fps)
25monoL.setNumFramesPool(poolSize)
26monoR.setCamera("right")
27monoR.setResolution(res)
28monoR.setFps(fps)
29monoR.setNumFramesPool(poolSize)
30
31xoutDotL = pipeline.create(dai.node.XLinkOut)
32xoutDotR = pipeline.create(dai.node.XLinkOut)
33xoutFloodL = pipeline.create(dai.node.XLinkOut)
34xoutFloodR = pipeline.create(dai.node.XLinkOut)
35
36xoutDotL.setStreamName('dot-left')
37xoutDotR.setStreamName('dot-right')
38xoutFloodL.setStreamName('flood-left')
39xoutFloodR.setStreamName('flood-right')
40streams = ['dot-left', 'dot-right', 'flood-left', 'flood-right']
41
42# Script node for frame routing and IR dot/flood alternate
43script = pipeline.create(dai.node.Script)
44script.setProcessor(dai.ProcessorType.LEON_CSS)
45script.setScript("""
46    dotBright = 0.8
47    floodBright = 0.1
48    LOGGING = False  # Set `True` for latency/timings debugging
49
50    node.warn(f'IR drivers detected: {str(Device.getIrDrivers())}')
51
52    flagDot = False
53    while True:
54        # Wait first for a frame event, received at MIPI start-of-frame
55        event = node.io['event'].get()
56        if LOGGING: tEvent = Clock.now()
57
58        # Immediately reconfigure the IR driver.
59        # Note the logic is inverted, as it applies for next frame
60        Device.setIrLaserDotProjectorIntensity(0 if flagDot else dotBright)
61        Device.setIrFloodLightIntensity(floodBright if flagDot else 0)
62        if LOGGING: tIrSet = Clock.now()
63
64        # Wait for the actual frames (after MIPI capture and ISP proc is done)
65        frameL = node.io['frameL'].get()
66        if LOGGING: tLeft = Clock.now()
67        frameR = node.io['frameR'].get()
68        if LOGGING: tRight = Clock.now()
69
70        if LOGGING:
71            latIR      = (tIrSet - tEvent               ).total_seconds() * 1000
72            latEv      = (tEvent - event.getTimestamp() ).total_seconds() * 1000
73            latProcL   = (tLeft  - event.getTimestamp() ).total_seconds() * 1000
74            diffRecvRL = (tRight - tLeft                ).total_seconds() * 1000
75            node.warn(f'T[ms] latEv:{latEv:5.3f} latIR:{latIR:5.3f} latProcL:{latProcL:6.3f} '
76                    + f' diffRecvRL:{diffRecvRL:5.3f}')
77
78        # Sync checks
79        diffSeq = frameL.getSequenceNum() - event.getSequenceNum()
80        diffTsEv = (frameL.getTimestamp() - event.getTimestamp()).total_seconds() * 1000
81        diffTsRL = (frameR.getTimestamp() - frameL.getTimestamp()).total_seconds() * 1000
82        if diffSeq or diffTsEv or (abs(diffTsRL) > 0.8):
83            node.error(f'frame/event desync! Fr-Ev: {diffSeq} frames,'
84                    + f' {diffTsEv:.3f} ms; R-L: {diffTsRL:.3f} ms')
85
86        # Route the frames to their respective outputs
87        node.io['dotL' if flagDot else 'floodL'].send(frameL)
88        node.io['dotR' if flagDot else 'floodR'].send(frameR)
89
90        flagDot = not flagDot
91""")
92
93# Linking
94monoL.frameEvent.link(script.inputs['event'])
95monoL.out.link(script.inputs['frameL'])
96monoR.out.link(script.inputs['frameR'])
97
98script.outputs['dotL'].link(xoutDotL.input)
99script.outputs['dotR'].link(xoutDotR.input)
100script.outputs['floodL'].link(xoutFloodL.input)
101script.outputs['floodR'].link(xoutFloodR.input)
102
103# Connect to device and start pipeline
104with dai.Device(pipeline) as device:
105    queues = [device.getOutputQueue(name=s, maxSize=4, blocking=False) for s in streams]
106
107    while True:
108        for q in queues:
109            pkt = q.tryGet()
110            if pkt is not None:
111                name = q.getName()
112                frame = pkt.getCvFrame()
113                cv2.imshow(name, frame)
114
115        if cv2.waitKey(5) == ord('q'):
116            break

Pipeline

React Flow

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