如何使opencv2中无法识别的面孔被标记为“未知”？

Question

我正在尝试使用 opencv2 运行一些 python 2.7 代码。目前，如果一个对象进入框架，代码会将其标记为它在照片数据库中看起来最像的那个。而不是这个，我希望它将未经训练的面孔标记为“未知”，这是我到目前为止的代码：

import cv2
import numpy as np

faceDetect=cv2.CascadeClassifier('haarcascade_frontalface_default.xml');
cam=cv2.VideoCapture(0);
rec=cv2.createLBPHFaceRecognizer();
rec.load("recognizer\\trainingData.yml")
id=0
font=cv2.cv.InitFont(cv2.cv.CV_FONT_HERSHEY_SIMPLEX,1,1,0,0)
#font=cv2.cv.InitFont(cv2.cv.CV_FONT_HERSHEY_COMPLEX_SMALL,3,1,0,1)
while (True):
   ret, img=cam.read();
   gray=cv2.cvtColor(img,cv2.COLOR_BGR2GRAY)
   faces=faceDetect.detectMultiScale(gray,1.3,5);
   for (x,y,w,h) in faces:
        #cv2.rectangle(img,(x,y),(x+w,y+h),(0,255,255),2)
        id,conf=rec.predict(gray[y:y+h, x:x+w])
        if(id==1):
            id="Admin"
            cv2.rectangle(img,(x,y),(x+w,y+h),(0,255,255),2)
        elif(id==2):
            id="Sonja"
            cv2.rectangle(img,(x,y),(x+w,y+h),(255,255,255),2)
            cv2.rectangle(img,(x,y),(x+w,y+h),(255,255,255),2)
        cv2.cv.PutText(cv2.cv.fromarray(img),str(id),(x,y+h),font,(255,255,255));
    cv2.imshow("Image",img);
    if(cv2.waitKey(1)==ord('q')):
        break;
cam.release()
cv2.destroyAllWindows()

并且训练器是通过这段代码运行的：

import os
import cv2
import numpy as np
from PIL import Image

recognizer=cv2.createLBPHFaceRecognizer();
path='dataSet'

def getImagesWithID(path):
   imagePaths=[os.path.join(path,f) for f in os.listdir(path)]
   faces=[]
   IDs=[]
   for imagePath in imagePaths:
        faceImg=Image.open(imagePath).convert('L');
        faceNp=np.array(faceImg,'uint8')
        ID=int(os.path.split(imagePath)[-1].split('.')[1])
        faces.append(faceNp)
        print ID
        IDs.append(ID)
        cv2.imshow("training",faceNp)
        cv2.waitKey(10)
    return np.array(IDs), faces

Ids, faces= getImagesWithID(path)
recognizer.train(faces, Ids)
recognizer.save('recognizer/trainingData.yml')
cv2.destroyAllWindows()

Answer 1

if conf<70:
        if id !=0 & id !=1:
            cv2.putText(img,"unknown",(x,y),cv2.FONT_HERSHEY_SIMPLEX,1,(0,255,0),2,cv2.LINE_AA)

Answer 2

import cv2
import numpy as np
from time import sleep


faceDetect=cv2.CascadeClassifier('haarcascade_frontalface_default.xml')
cam=cv2.VideoCapture(0)
rec=cv2.createLBPHFaceRecognizer()
rec.load("recognizer/trainingData.yml")
id=0
font=cv2.cv.InitFont(cv2.cv.CV_FONT_HERSHEY_COMPLEX_SMALL,1,1,0,1)
while True:
    ret,img=cam.read();
    gray=cv2.cvtColor(img,cv2.COLOR_BGR2GRAY)
    faces=faceDetect.detectMultiScale(gray, 1.3, 5)
    for(x,y,w,h) in faces:
        cv2.rectangle(img, (x,y), (x+w,y+h), (255, 0, 0), 2)
        id,conf=rec.predict(gray[y:y+h, x:x+w])
        if(conf<70):
            if(id==1):
                id="Admin"
            if(id==2):
                id="Sonja"
        else:
            id="unknown"

        cv2.cv.PutText(cv2.cv.fromarray(img), str(id), (x,y+h), font,255)
        print ('ok')
    cv2.imshow("Face",img)
    if (cv2.waitKey(1) & 0xFF==ord('q')):
        break
cam.release()
cv2.destroyAllWindows()

Answer 3

如果你打印 conf 的值，你可以看到如果面部在你创建的数据集中，该值将小于 70，否则 的值>conf 将超过 70。如果您希望系统更准确地检查 conf 的值并根据您的意愿提供任何其他值，则值 70 由我设置。

Answer 4

我假设您的 rec.predict 方法返回已识别面孔的 id。在这种情况下，您可以在 for (x,y,w,h) in faces: 循环中为没有 id 的面添加“else”条件，如下所示：

        if(id==1):
            id="Admin"
            cv2.rectangle(img,(x,y),(x+w,y+h),(0,255,255),2)
            cv2.putText(img,"Admin",x+h/2,y+w+40),cv2.FONT_HERSHEY_SIMPLEX,0.6,(0,255,255),2)
        elif(id==2):
            id="Sonja"
            #cv2.rectangle(img,(x,y),(x+w,y+h),(255,255,255),2)
            cv2.rectangle(img,(x,y),(x+w,y+h),(255,255,255),2)
            cv2.putText(img,"Sonja",x+h/2,y+w+40),cv2.FONT_HERSHEY_SIMPLEX,0.6,(255,255,255),2)
        else:
            cv2.rectangle(img,(x,y),(x+w,y+h),(0,0,255),2)#Red
            cv2.putText(img,"Unknown",(x+h/2,y+w+40),cv2.FONT_HERSHEY_SIMPLEX,0.6,(0,0,255),2)

另外，我实现 putText 方法的方式与您展示的不同。