使用opencv自动检测面部并拍摄快照

Question

我正在与我的大学一起进行人脸识别项目。如果在关闭网络摄像头之前自动检测到面部，我正在尝试拍摄快照并保存它。 我现在拥有的是打开凸轮并等待如果检测到面部，然后按“q”拍摄快照并保存图像。 代码如下：

import numpy as np
import cv2
import time

#import the cascade for face detection
face_cascade = cv2.CascadeClassifier('haarcascade_frontalface_default.xml')



def TakeSnapshotAndSave():
    # access the webcam (every webcam has a number, the default is 0)
    cap = cv2.VideoCapture(0)

    while(True):
        # Capture frame-by-frame
        ret, frame = cap.read()

        # to detect faces in video
        gray = cv2.cvtColor(frame, cv2.COLOR_BGR2GRAY)
        faces = face_cascade.detectMultiScale(gray, 1.3, 5)

        for (x,y,w,h) in faces:
            cv2.rectangle(frame,(x,y),(x+w,y+h),(255,0,0),2)
            roi_gray = gray[y:y+h, x:x+w]
            roi_color = frame[y:y+h, x:x+w]

        x = 0
        y = 20
        text_color = (0,255,0)
        # write on the live stream video
        cv2.putText(frame, "Press q when ready", (x,y), cv2.FONT_HERSHEY_PLAIN, 1.0, text_color, thickness=2)


        # if you want to convert it to gray uncomment and display gray not fame
        #gray = cv2.cvtColor(frame, cv2.COLOR_BGR2GRAY)

        # Display the resulting frame
        cv2.imshow('frame',frame)
        # press the letter "q" to save the picture
        if cv2.waitKey(1) & 0xFF == ord('q'):
            # write the captured image with this name
            cv2.imwrite('try.jpg',frame)
            break

    # When everything done, release the capture
    cap.release()
    cv2.destroyAllWindows()


if __name__ == "__main__":
    TakeSnapshotAndSave()

提前谢谢你

Answer 1

在 for (x,y,w,h) in faces: 循环中执行 imwrite()。如果您使用固定文件名，您最后检测到的人脸将被保存，其余的将被覆盖

Answer 2

我修改了您的代码以保存 10 张图像仅用于测试，如果您想要无限的照片，只需更改 while 条件。因此，在您的代码中，您覆盖了当前图像，因此我更改了字符串参数，以便可以拍摄大量照片。

import numpy as np
import cv2
import time

#import the cascade for face detection
face_cascade = cv2.CascadeClassifier('haarcascade_frontalface_default.xml')

def TakeSnapshotAndSave():
    # access the webcam (every webcam has a number, the default is 0)
    cap = cv2.VideoCapture(0)

    num = 0 
    while num<10:
        # Capture frame-by-frame
        ret, frame = cap.read()

        # to detect faces in video
        gray = cv2.cvtColor(frame, cv2.COLOR_BGR2GRAY)
        faces = face_cascade.detectMultiScale(gray, 1.3, 5)

        for (x,y,w,h) in faces:
            cv2.rectangle(frame,(x,y),(x+w,y+h),(255,0,0),2)
            roi_gray = gray[y:y+h, x:x+w]
            roi_color = frame[y:y+h, x:x+w]

        x = 0
        y = 20
        text_color = (0,255,0)

        cv2.imwrite('opencv'+str(num)+'.jpg',frame)
        num = num+1

    # When everything done, release the capture
    cap.release()
    cv2.destroyAllWindows()


if __name__ == "__main__":
    TakeSnapshotAndSave()