Now that we have converted the image to grayscale, shrunk the image, and equalized the histogram, we are ready to detect the faces using the CascadeClassifier::detectMultiScale() function! There are many parameters that we pass to this function:
- minFeatureSize: This parameter determines the minimum face size that we care about, typically 20x20 or 30x30 pixels but this depends on your use case and image size. If you are performing face detection on a webcam or smartphone where the face will always be very close to the camera, you could enlarge this to 80 x 80 to have much faster detections, or if you want to detect far away faces, such as on a beach with friends, then leave this as 20x20.
- searchScaleFactor: This parameter ...
