这是我写的代码，我想在终端上显示检测到的人脸数量，我尝试了一些方法（如if face_coordinates: cv2.imshow(“a human was found”, webcam)等，但都没有效果

import cv2# load some pre-trained data on front faces (haarcascade algorithm)trained_face_data = cv2.CascadeClassifier('haarcascade_frontalface_default.xml')# to capture video from webcamwebcam = cv2.VideoCapture(1)# iterate forever over frameswhile True:    successful_frame_read, frame = webcam.read()    #flip the video (mirror)    flipped_frame = cv2.flip(frame, 1)    # convert to grayscale    grayscaled_img = cv2.cvtColor(flipped_frame, cv2.COLOR_BGR2GRAY)    # detect faces    face_coordinates = trained_face_data.detectMultiScale(grayscaled_img)    # show rectangles around the face    for (x, y, w, h) in face_coordinates:        cv2.rectangle(flipped_frame, (x, y), (x+w, y+h), (0, 255, 0), 2)    # show the webcam    cv2.imshow("Fadi's face detector system", flipped_frame)    key = cv2.waitKey(1)    # exit app if Q or q are pressed    if key==81 or key==113:        break    if face_coordinates:  # python types can be coerced to boolean    cv2.imshow("Human was found!", webcam)    continue    else:        cv2.imshow("no human was found...", webcam)        continuewebcam.release()

回答：

为了在终端打印检测到的人脸数量，我尝试了统计不同的检测到的人脸，并根据此在终端打印检测到的人数。我对你的代码做了一些小的修改如下。

import cv2# load some pre-trained data on front faces (haarcascade algorithm)trained_face_data = cv2.CascadeClassifier(cv2.data.haarcascades +'haarcascade_frontalface_default.xml')# to capture video from webcamwebcam = cv2.VideoCapture(0)# iterate forever over frameswhile True:    successful_frame_read, frame = webcam.read()    #flip the video (mirror)    flipped_frame = cv2.flip(frame, 1)    # convert to grayscale    grayscaled_img = cv2.cvtColor(flipped_frame, cv2.COLOR_BGR2GRAY)    # detect faces    face_coordinates = trained_face_data.detectMultiScale(grayscaled_img)    count=0    # show rectangles around the face    for (x, y, w, h) in face_coordinates:        count=count+1        cv2.rectangle(flipped_frame, (x, y), (x+w, y+h), (0, 255, 0), 3)    # show the webcam    cv2.imshow("Fadi's face detector system", flipped_frame)    key = cv2.waitKey(1)    # exit app if Q or q are pressed    if key==81 or key==113:        break    # python types can be coerced to boolean    if count==1:        print(count," human found")    elif count>0:        print(count," humans found")    else:        print("No human was found")webcam.release()