Object Tracker Remap
This example demonstrates running YOLOv6-nano detection with the ObjectTracker node and remapping bounding boxes onto a colorized depth frame using transformation metadata, ensuring accurate alignment across streams (RGB ↔ Depth).Demo

Pipeline
Source code
Python
C++
Python
PythonGitHub
1#!/usr/bin/env python3
2
3import cv2
4import depthai as dai
5import numpy as np
6
7def colorizeDepth(frameDepth):
8 invalidMask = frameDepth == 0
9 # Log the depth, minDepth and maxDepth
10 try:
11 minDepth = np.percentile(frameDepth[frameDepth != 0], 3)
12 maxDepth = np.percentile(frameDepth[frameDepth != 0], 95)
13 logDepth = np.log(frameDepth, where=frameDepth != 0)
14 logMinDepth = np.log(minDepth)
15 logMaxDepth = np.log(maxDepth)
16 np.nan_to_num(logDepth, copy=False, nan=logMinDepth)
17 # Clip the values to be in the 0-255 range
18 logDepth = np.clip(logDepth, logMinDepth, logMaxDepth)
19
20 # Interpolate only valid logDepth values, setting the rest based on the mask
21 depthFrameColor = np.interp(logDepth, (logMinDepth, logMaxDepth), (0, 255))
22 depthFrameColor = np.nan_to_num(depthFrameColor)
23 depthFrameColor = depthFrameColor.astype(np.uint8)
24 depthFrameColor = cv2.applyColorMap(depthFrameColor, cv2.COLORMAP_JET)
25 # Set invalid depth pixels to black
26 depthFrameColor[invalidMask] = 0
27 except IndexError:
28 # Frame is likely empty
29 depthFrameColor = np.zeros((frameDepth.shape[0], frameDepth.shape[1], 3), dtype=np.uint8)
30 except Exception as e:
31 raise e
32 return depthFrameColor
33
34# Create pipeline
35with dai.Pipeline() as pipeline:
36 cameraNode = pipeline.create(dai.node.Camera).build()
37 detectionNetwork = pipeline.create(dai.node.DetectionNetwork).build(cameraNode, dai.NNModelDescription("yolov6-nano"))
38 objectTracker = pipeline.create(dai.node.ObjectTracker)
39 labelMap = detectionNetwork.getClasses()
40 monoLeft = pipeline.create(dai.node.Camera).build(dai.CameraBoardSocket.CAM_B)
41 monoRight = pipeline.create(dai.node.Camera).build(dai.CameraBoardSocket.CAM_C)
42 stereo = pipeline.create(dai.node.StereoDepth)
43
44 # Linking
45 monoLeftOut = monoLeft.requestOutput((1280, 720), type=dai.ImgFrame.Type.NV12)
46 monoRightOut = monoRight.requestOutput((1280, 720), type=dai.ImgFrame.Type.NV12)
47 monoLeftOut.link(stereo.left)
48 monoRightOut.link(stereo.right)
49
50 detectionNetwork.out.link(objectTracker.inputDetections)
51 detectionNetwork.passthrough.link(objectTracker.inputDetectionFrame)
52 detectionNetwork.passthrough.link(objectTracker.inputTrackerFrame)
53
54 stereo.setRectification(True)
55 stereo.setExtendedDisparity(True)
56 stereo.setLeftRightCheck(True)
57 stereo.setSubpixel(True)
58
59
60 qRgb = detectionNetwork.passthrough.createOutputQueue()
61 qTrack = objectTracker.out.createOutputQueue()
62 qDepth = stereo.disparity.createOutputQueue()
63
64 pipeline.start()
65
66 def displayFrame(name: str, frame: dai.ImgFrame, tracklets: dai.Tracklets):
67 color = (0, 255, 0)
68 assert tracklets.getTransformation() is not None
69 cvFrame = frame.getFrame() if frame.getType() == dai.ImgFrame.Type.RAW16 else frame.getCvFrame()
70 if(frame.getType() == dai.ImgFrame.Type.RAW16):
71 cvFrame = colorizeDepth(cvFrame)
72 for tracklet in tracklets.tracklets:
73 # Get the shape of the frame from which the detections originated for denormalization
74 normShape = tracklets.getTransformation().getSize()
75
76 # Create rotated rectangle to remap
77 # Here we use an intermediate dai.Rect to create a dai.RotatedRect to simplify construction and denormalization
78 rotRect = dai.RotatedRect(tracklet.roi.denormalize(normShape[0], normShape[1]), 0)
79 # Remap the detection rectangle to target frame
80 remapped = tracklets.getTransformation().remapRectTo(frame.getTransformation(), rotRect)
81 # Remapped rectangle could be rotated, so we get the bounding box
82 bbox = [int(l) for l in remapped.getOuterRect()]
83 cv2.putText(
84 cvFrame,
85 labelMap[tracklet.label],
86 (bbox[0] + 10, bbox[1] + 20),
87 cv2.FONT_HERSHEY_TRIPLEX,
88 0.5,
89 255,
90 )
91 cv2.putText(
92 cvFrame,
93 f"{int(tracklet.srcImgDetection.confidence * 100)}%",
94 (bbox[0] + 10, bbox[1] + 40),
95 cv2.FONT_HERSHEY_TRIPLEX,
96 0.5,
97 255,
98 )
99 cv2.rectangle(cvFrame, (bbox[0], bbox[1]), (bbox[2], bbox[3]), color, 2)
100 # Show the frame
101 cv2.imshow(name, cvFrame)
102
103 while pipeline.isRunning():
104 inRgb: dai.ImgFrame = qRgb.get()
105 inTrack: dai.Tracklets = qTrack.get()
106 inDepth: dai.ImgFrame = qDepth.get()
107 hasRgb = inRgb is not None
108 hasDepth = inDepth is not None
109 hasTrack = inTrack is not None
110 if hasRgb:
111 displayFrame("rgb", inRgb, inTrack)
112 if hasDepth:
113 displayFrame("depth", inDepth, inTrack)
114 if cv2.waitKey(1) == ord("q"):
115 pipeline.stop()
116 break
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