如何使用 python 在 opencv 中打印 x 和 y 坐标？

Question

这是我下面的代码，它会输出人脸被识别但现在我想打印出人被识别的 x 和 y 坐标。我会在 for 循环中还是在其外部包含 x 和 y 坐标的 print 语句？请帮忙！谢谢！

import numpy as np
import cv2
import time
import RPi.GPIO as GPIO
GPIO.setmode(GPIO.BCM)
GPIO.setwarnings(False)
GPIO.setup(18,GPIO.OUT)
face_cascade = cv2.CascadeClassifier('haarcascade_frontalface_default.xml')
prevTime = 0
## This will get our web camera
 
cap = cv2.VideoCapture(0)
font = cv2.FONT_HERSHEY_SIMPLEX
while True:
    retval, frame = cap.read()
    if not retval:
        break
    _, img = cap.read()              ## This gets each frame from the video, cap.read returns 2 variables flag - indicate frame is correct and 2nd is f
    ##img = cv2.imread('Z.png') Then we get our image we want to use
    gray = cv2.cvtColor(img, cv2.COLOR_BGR2GRAY)   # This method only works on gray skin images, so we have to convert the gray scale to rgb image
    faces = face_cascade.detectMultiScale(gray, 1.1, 5) ## Next, we detect the faces
    if len(faces) > 0:
        print("[INFO] found {0} faces!".format(len(faces)))
        GPIO.output(18,GPIO.HIGH)
    else:
        print("No face")
        GPIO.output(18,GPIO.LOW)
    for (x, y, w, h) in faces:   ## We draw a rectangle around the faces so we can see it correctly
        cv2.rectangle(img, (x, y), (x+w, y+h), (255, 0, 0))         ## The faces will be a list of coordinates
        cv2.putText(img, 'Myface', (x, y), font, fontScale=1, color=(255,70,120),thickness=2)
    cv2.putText(frame, 'Number of Faces Detected: ' + str, (0,  100), cv2.FONT_HERSHEY_SIMPLEX, 1, (0, 255, 0))
    cv2.imshow('img', img) ## Last we show the image
    x = cv2.waitKey(30) & 0xff
    if x==27:
        break
## Press escape to exit the program
cap.release()

Answer 1

你应该在里面打印，打印检测到的 4 个角：

print('Top left corner: 'str(x)+' '+str(y))
print('Top right corner: 'str(x+w)+' '+str(y))
etc

Answer 2

把它放在循环中。试试这个：

faces = face_cascade.detectMultiScale(gray, 1.1, 5) 
for (x, y, w, h) in faces:
    x1 = x
    x2 = x + w
    y1 = y
    y2 = y + h
    print ("diaginal point 1 (x1,y1) = ({},{})".format(x1, y1))
    print ("diaginal point 2 (x2,y2) = ({},{})".format(x2, y2))

但是，如果您不希望它一直打印，并且在您按下“P”或“p”等特定键时打印一次，则使用此代码：

faces = face_cascade.detectMultiScale(gray, 1.1, 5) 
for (x, y, w, h) in faces:
    
    x1 = x
    x2 = x + w
    y1 = y
    y2 = y + h

    k = cv2.waitKey(10) x00F
    if k == ord("p"):
         print ("diaginal point 1 (x1,y1) = ({},{})".format(x1, y1))
         print ("diaginal point 2 (x2,y2) = ({},{})".format(x2, y2))

所以只要你按下“p”，它就会打印点 1 和点 2 的 x 和 y 坐标:) 为了简单起见，我提到了 x1、y1、x2 和 y2。

希望对您有所帮助。

如何使用 python 在 opencv 中打印 x 和 y 坐标？

How to print x and y coordinates in opencv using python?

python

opencv

face-detection

face-recognition

raspberry-pi4