face detection , not face detected

Question

I am trying to do face detection but it does not detect any face.

this is the function I have created for face detection

def faceDetection(test_img):
     gray_img=cv2.cvtColor(test_img,cv2.COLOR_BGR2GRAY)
     face_haar_cascade=cv2.CascadeClassifier('haarcascade_frontalface_default.xml')
     # haar classifier
     faces=face_haar_cascade.detectMultiScale(gray_img,scaleFactor=1.32,minNeighbors=5)

     return faces,gray_img

this is used in

test_img=cv2.imread('pic.png')
faces_detected,gray_img=fr.faceDetection(test_img)
print("faces_detected:",faces_detected)


for (x,y,w,h) in faces_detected:
    cv2.rectangle(test_img,(x,y),(x+w,y+h),(255,0,0),thickness=5)

resized_img=cv2.resize(test_img,(500,500))
cv2.imshow("face",resized_img)
cv2.waitKey(0)
cv2.destroyAllWindows

but when I run this script it does not show any face detected simply give output this

faces_detected: ()

and no box around image

Are you sure you have downloaded [haarcascade_frontalface_default.xml](https://stackoverflow.com/questions/11537585/where-can-i-find-haar-cascades-xml-files) to the correct destination? — zteffi, Jul 08 '19 at 17:04
this is the link https://github.com/opencv/opencv/blob/master/data/haarcascades/haarcascade_frontalface_default.xml — itsvinayak, Jul 08 '19 at 17:06
Try reducing scaleFactor, it's pretty high. Try default value of 1.1 — zteffi, Jul 08 '19 at 17:16
no, it doesn't work , it detect but not face by reducing scaleFactor — itsvinayak, Jul 09 '19 at 04:02

score 2 · Accepted Answer · answered Jul 09 '19 at 01:29

Try using a different haar cascade. The default one is haarcascade_frontalface_alt.xml

face_haar_cascade = cv2.CascadeClassifier('haarcascade_frontalface_alt.xml')

Change the scale factor you use for the cascade. If that doesn't work you can also reduce also the number of neighbors to maybe 2.

faces = face_haar_cascade.detectMultiScale(gray_img, scaleFactor=1.1, minNeighbors=5);

Check the number of faces you found

print('Faces found: ', len(faces))

face detection , not face detected

1 Answers1