OpenCV Python Example

A short example of using OpenCV on Nextjournal, adapted from code by Shantnu Tiwari. The default Python environment includes the opencv-python-headless package, as we cannot support OpenCV's GUI functions such as imshow(); thus, the primary difference is using imwrite() instead.

import cv2
import sys
# Get user supplied values
imagePath = 
abba.png
cascPath = cv2.data.haarcascades + "haarcascade_frontalface_default.xml"
# Create the haar cascade
faceCascade = cv2.CascadeClassifier(cascPath)
# Read the image
image = cv2.imread(imagePath)
gray = cv2.cvtColor(image, cv2.COLOR_BGR2GRAY)
# Detect faces in the image
faces = faceCascade.detectMultiScale(
    gray,
    scaleFactor=1.1,
    minNeighbors=5,
    minSize=(30, 30)
    #flags = cv2.CV_HAAR_SCALE_IMAGE
)
print("Found {0} faces!".format(len(faces)))
# Draw a rectangle around the faces
for (x, y, w, h) in faces:
    cv2.rectangle(image, (x, y), (x+w, y+h), (0, 255, 0), 2)
cv2.imwrite("/results/abba-faces.png", image)
0.9s
Python
Python 3
True
Runtimes (1)