Mobilenet video DepthAI

mobilenet_video.py

#!/usr/bin/env python3

from pathlib import Path
import sys
import cv2
import depthai as dai
import numpy as np

# Get argument first
nnPath = str((Path(__file__).parent / Path('models/mobilenet-ssd_openvino_2021.2_5shave.blob')).resolve().absolute())
if len(sys.argv) > 1:
    nnPath = sys.argv[1]

if not Path(nnPath).exists():
    import sys
    raise FileNotFoundError(f'Required file/s not found, please run "{sys.executable} install_requirements.py"')

# MobilenetSSD label texts
labelMap = ["background", "aeroplane", "bicycle", "bird", "boat", "bottle", "bus", "car", "cat", "chair", "cow",
            "diningtable", "dog", "horse", "motorbike", "person", "pottedplant", "sheep", "sofa", "train", "tvmonitor"]

# Create pipeline
pipeline = dai.Pipeline()
pipeline.setOpenVINOVersion(dai.OpenVINO.Version.VERSION_2021_2)

# Define sources and outputs
camRgb = pipeline.createColorCamera()
nn = pipeline.createMobileNetDetectionNetwork()

xoutVideo = pipeline.createXLinkOut()
nnOut = pipeline.createXLinkOut()

xoutVideo.setStreamName("video")
nnOut.setStreamName("nn")

# Properties
camRgb.setPreviewSize(300, 300)    # NN input
camRgb.setResolution(dai.ColorCameraProperties.SensorResolution.THE_1080_P)
camRgb.setInterleaved(False)
camRgb.setPreviewKeepAspectRatio(False)
# Define a neural network that will make predictions based on the source frames
nn.setConfidenceThreshold(0.5)
nn.setBlobPath(nnPath)
nn.setNumInferenceThreads(2)
nn.input.setBlocking(False)
# Has to be 1:1 aspect ratio to match the NN input aspect ratio (300x300)
camRgb.setVideoSize(1080, 1080)

# Linking
camRgb.video.link(xoutVideo.input)
camRgb.preview.link(nn.input)
nn.out.link(nnOut.input)

# Connect to device and start pipeline
with dai.Device(pipeline) as device:

    # Output queues will be used to get the frames and nn data from the outputs defined above
    qVideo = device.getOutputQueue(name="video", maxSize=4, blocking=False)
    qDet = device.getOutputQueue(name="nn", maxSize=4, blocking=False)

    videoFrame = None
    detections = []

    # nn data, being the bounding box locations, are in <0..1> range - they need to be normalized with frame width/height
    def frameNorm(frame, bbox):
        normVals = np.full(len(bbox), frame.shape[0])
        normVals[::2] = frame.shape[1]
        return (np.clip(np.array(bbox), 0, 1) * normVals).astype(int)

    def displayFrame(name, frame):
        color = (255, 0, 0)
        for detection in detections:
            bbox = frameNorm(frame, (detection.xmin, detection.ymin, detection.xmax, detection.ymax))
            cv2.putText(frame, labelMap[detection.label], (bbox[0] + 10, bbox[1] + 20), cv2.FONT_HERSHEY_TRIPLEX, 0.5, color)
            cv2.putText(frame, f"{int(detection.confidence * 100)}%", (bbox[0] + 10, bbox[1] + 40), cv2.FONT_HERSHEY_TRIPLEX, 0.5, color)
            cv2.rectangle(frame, (bbox[0], bbox[1]), (bbox[2], bbox[3]), color, 2)
        # Show the frame
        cv2.imshow(name, frame)

    while True:
        # Instead of get (blocking), we use tryGet (nonblocking) which will return the available data or None otherwise
        inVideo = qVideo.tryGet()
        inDet = qDet.tryGet()

        if inVideo is not None:
            videoFrame = inVideo.getCvFrame()

        if inDet is not None:
            detections = inDet.detections

        if videoFrame is not None:
            displayFrame("video", videoFrame)

        if cv2.waitKey(1) == ord('q'):
            break