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


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.

python using imageai to detect hololens less than 1 fps

With the previous sample code, I couldnโ€™t process more than 1 frame per second. So, I started to make some improvements and I got this result

python using imageai to detect hololens little more than 1 fps

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()
# init camera
execution_path = os.getcwd()
camera = cv2.VideoCapture(0)
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
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
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'):
# Release handle to the webcam

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

python using imageai to detect hololens no opencv camera preview

So, now itโ€™s time to read and learn of the deep code on ImageAI. Fun times!

Happy coding!

Greetings @ Burlington

El Bruno



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