DepthAI Tutorials
DepthAI API References

ON THIS PAGE

  • Feature Detector
  • Demo
  • Setup
  • Source code

Feature Detector

Example shows capabilities of FeatureTracker. It only detects features. Feature Tracker example also tracks these features.

Demo

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
GitHub
1#!/usr/bin/env python3
2
3import cv2
4import depthai as dai
5
6
7# Create pipeline
8pipeline = dai.Pipeline()
9
10# Define sources and outputs
11monoLeft = pipeline.create(dai.node.MonoCamera)
12monoRight = pipeline.create(dai.node.MonoCamera)
13featureTrackerLeft = pipeline.create(dai.node.FeatureTracker)
14featureTrackerRight = pipeline.create(dai.node.FeatureTracker)
15
16xoutPassthroughFrameLeft = pipeline.create(dai.node.XLinkOut)
17xoutTrackedFeaturesLeft = pipeline.create(dai.node.XLinkOut)
18xoutPassthroughFrameRight = pipeline.create(dai.node.XLinkOut)
19xoutTrackedFeaturesRight = pipeline.create(dai.node.XLinkOut)
20xinTrackedFeaturesConfig = pipeline.create(dai.node.XLinkIn)
21
22xoutPassthroughFrameLeft.setStreamName("passthroughFrameLeft")
23xoutTrackedFeaturesLeft.setStreamName("trackedFeaturesLeft")
24xoutPassthroughFrameRight.setStreamName("passthroughFrameRight")
25xoutTrackedFeaturesRight.setStreamName("trackedFeaturesRight")
26xinTrackedFeaturesConfig.setStreamName("trackedFeaturesConfig")
27
28# Properties
29monoLeft.setResolution(dai.MonoCameraProperties.SensorResolution.THE_400_P)
30monoLeft.setCamera("left")
31monoRight.setResolution(dai.MonoCameraProperties.SensorResolution.THE_400_P)
32monoRight.setCamera("right")
33
34# Disable optical flow
35featureTrackerLeft.initialConfig.setMotionEstimator(False)
36featureTrackerRight.initialConfig.setMotionEstimator(False)
37
38# Linking
39monoLeft.out.link(featureTrackerLeft.inputImage)
40featureTrackerLeft.passthroughInputImage.link(xoutPassthroughFrameLeft.input)
41featureTrackerLeft.outputFeatures.link(xoutTrackedFeaturesLeft.input)
42xinTrackedFeaturesConfig.out.link(featureTrackerLeft.inputConfig)
43
44monoRight.out.link(featureTrackerRight.inputImage)
45featureTrackerRight.passthroughInputImage.link(xoutPassthroughFrameRight.input)
46featureTrackerRight.outputFeatures.link(xoutTrackedFeaturesRight.input)
47xinTrackedFeaturesConfig.out.link(featureTrackerRight.inputConfig)
48
49featureTrackerConfig = featureTrackerRight.initialConfig.get()
50
51print("Press 's' to switch between Harris and Shi-Thomasi corner detector!")
52
53# Connect to device and start pipeline
54with dai.Device(pipeline) as device:
55
56    # Output queues used to receive the results
57    passthroughImageLeftQueue = device.getOutputQueue("passthroughFrameLeft", 8, False)
58    outputFeaturesLeftQueue = device.getOutputQueue("trackedFeaturesLeft", 8, False)
59    passthroughImageRightQueue = device.getOutputQueue("passthroughFrameRight", 8, False)
60    outputFeaturesRightQueue = device.getOutputQueue("trackedFeaturesRight", 8, False)
61
62    inputFeatureTrackerConfigQueue = device.getInputQueue("trackedFeaturesConfig")
63
64    leftWindowName = "left"
65    rightWindowName = "right"
66
67    def drawFeatures(frame, features):
68        pointColor = (0, 0, 255)
69        circleRadius = 2
70        for feature in features:
71            cv2.circle(frame, (int(feature.position.x), int(feature.position.y)), circleRadius, pointColor, -1, cv2.LINE_AA, 0)
72
73    while True:
74        inPassthroughFrameLeft = passthroughImageLeftQueue.get()
75        passthroughFrameLeft = inPassthroughFrameLeft.getFrame()
76        leftFrame = cv2.cvtColor(passthroughFrameLeft, cv2.COLOR_GRAY2BGR)
77
78        inPassthroughFrameRight = passthroughImageRightQueue.get()
79        passthroughFrameRight = inPassthroughFrameRight.getFrame()
80        rightFrame = cv2.cvtColor(passthroughFrameRight, cv2.COLOR_GRAY2BGR)
81
82        trackedFeaturesLeft = outputFeaturesLeftQueue.get().trackedFeatures
83        drawFeatures(leftFrame, trackedFeaturesLeft)
84
85        trackedFeaturesRight = outputFeaturesRightQueue.get().trackedFeatures
86        drawFeatures(rightFrame, trackedFeaturesRight)
87
88        # Show the frame
89        cv2.imshow(leftWindowName, leftFrame)
90        cv2.imshow(rightWindowName, rightFrame)
91
92        key = cv2.waitKey(1)
93        if key == ord('q'):
94            break
95        elif key == ord('s'):
96            if featureTrackerConfig.cornerDetector.type == dai.FeatureTrackerConfig.CornerDetector.Type.HARRIS:
97                featureTrackerConfig.cornerDetector.type = dai.FeatureTrackerConfig.CornerDetector.Type.SHI_THOMASI
98                print("Switching to Shi-Thomasi")
99            else:
100                featureTrackerConfig.cornerDetector.type = dai.FeatureTrackerConfig.CornerDetector.Type.HARRIS
101                print("Switching to Harris")
102
103            cfg = dai.FeatureTrackerConfig()
104            cfg.set(featureTrackerConfig)
105            inputFeatureTrackerConfigQueue.send(cfg)

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