#Python – Detecting #Hololens in realtime in webcam feed using #ImageAI and #OpenCV with performance improvements

Hi!

In my previous post I created a sample on how to use ImageAI and OpenCV to detect Hololens from a webcam frame (see references). I added some code to the last sample, and I found that the performance was not very good.

With the previous sample code, I couldn’t process more than 1 frame per second. So, I started to make some improvements and I got this result

Not an amazing one, but still is nice to have more than 1 frame per second analyzed.

	# load HL detection model from imageAI
	# open camera with openCV, analyze frame by frame
	# draw a red frame around the detected object
	# display FPS, resize image to 1/4 to improve performance
	from imageai.Detection.Custom import CustomObjectDetection
	import os
	import cv2
	import time
	detector = CustomObjectDetection()
	detector.setModelTypeAsYOLOv3()
	detector.setModelPath("hololens-ex-60–loss-2.76.h5")
	detector.setJsonPath("detection_config.json")
	detector.loadModel()
	# init camera
	execution_path = os.getcwd()
	camera = cv2.VideoCapture(0)
	camera.set(cv2.CAP_PROP_FRAME_WIDTH,640)
	camera.set(cv2.CAP_PROP_FRAME_HEIGHT,480)
	while True:
	# FPS process
	start_time = time.time()
	# Grab a single frame of video
	ret, frame = camera.read()
	fast_frame = cv2.resize(frame, (0, 0), fx=0.25, fy=0.25)
	detected_image, detections = detector.detectObjectsFromImage(input_image=fast_frame, input_type="array", output_type="array")
	for detection in detections:
	# frame for the detected object
	(x1, y1, x2, y2) = detection["box_points"]
	x1 *= 4
	y1 *= 4
	x2 *= 4
	y2 *= 4
	cv2.rectangle(frame, (x1, y1), (x2, y2), (0, 0, 255), 2)
	# Draw a label with the detected object type below the frame
	font = cv2.FONT_HERSHEY_DUPLEX
	cv2.putText(frame, detection["name"], (x1 + 6, y1 – 6), font, 1.0, (255, 255, 255), 1)
	#display FPS
	fpsInfo = "FPS: " + str(1.0 / (time.time() – start_time)) # FPS = 1 / time to process loop
	print(fpsInfo)
	font = cv2.FONT_HERSHEY_DUPLEX
	cv2.putText(frame, fpsInfo, (10, 20), font, 0.4, (255, 255, 255), 1)
	# Display the resulting image
	cv2.imshow('Video', frame)
	# Hit 'q' on the keyboard to quit!
	if cv2.waitKey(1) & 0xFF == ord('q'):
	break
	# Release handle to the webcam
	video_capture.release()
	cv2.destroyAllWindows()

view raw ImageAIRealTimeWebCamPerformance.py hosted with ❤ by GitHub

I even remove all the camera preview and still works in less than 1FPS.

So, now it’s time to read and learn of the deep code on ImageAI. Fun times!

Happy coding!

Greetings @ Burlington

El Bruno

References

• Detecting Hololens in realtime in webcam feed using ImageAI and OpenCV (thanks to @OlafenwaMoses) https://elbruno.com/2019/08/07/python-detecting-hololens-in-realtime-in-webcam-feed-using-imageai-and-opencv-thanks-to-olafenwamoses/
• Image AI http://imageai.org/
• GitHub, ImageAI https://github.com/OlafenwaMoses/ImageAI
• Train Object Detection AI with 6 lines of code https://medium.com/deepquestai/train-object-detection-ai-with-6-lines-of-code-6d087063f6ff