face_cascade.detectMultiScale

The face_cascade.detectMultiScale method is a function from the OpenCV library used for detecting faces in images or videos. It takes an image or a frame from a video as input and returns a list of rectangles that represent the detected faces in the image or video frame. The method works by using a Cascade Classifier, which is a machine learning algorithm that analyzes features of an image to detect objects. The detectMultiScale method applies this algorithm to the input image or video frame at different scales to detect faces of various sizes. The method also allows the user to adjust the parameters such as the scale factor, minimum neighbors, and minimum and maximum size of the detected faces to improve the accuracy of the detection.