facedetection with opencv and python only detect eye region
Question: I wrote the script by looking at this website and it works perfectly but the
only problem when I run it on my computer is it only detects the eye region.
<https://pythonprogramming.net/haar-cascade-face-eye-detection-python-opencv-
tutorial/>

Below is the script I wrote based on the website.

    
    
    import numpy as np
    import cv2
    
    face_cascade = cv2.CascadeClassifier('haarcascade_frontalface_default.xml')
    eye_cascade = cv2.CascadeClassifier('haarcascade_eye.xml')
    
    image = cv2.imread('frame119.jpg')  
    gray = cv2.cvtColor(image, cv2.COLOR_BGR2GRAY)
    faces = face_cascade.detectMultiScale(gray, 1.3, 5)
    
    for (x,y,w,h) in faces:
        cv2.rectangle(image,(x,y),(x+w,y+h),(255,0,0),2)
        roi_gray = gray[y:y+h, x:x+w]
        roi_color = image[y:y+h, x:x+w]
    
        eyes = eye_cascade.detectMultiScale(roi_gray)
        for (ex,ey,ew,eh) in eyes:
            cv2.rectangle(roi_color,(ex,ey),(ex+ew,ey+eh),(0,255,0),2)
    
    cv2.imshow('image', image)
    cv2.waitKey(0)
    cv2.destroyAllWindows()
    

do I need to add an additional line to fix the problem? Also, the image is in
680x480 dimension, I think that maybe one of the reason why it only detects
eye region of the image but I do not have any idea regarding that.

Thank you for the help.


Answer: It is not possible to detect eyes if no face is detected .

so try these modification

    
    
    import numpy as np
    import cv2
    
    face_cascade = cv2.CascadeClassifier('haarcascade_frontalface_default.xml')
    eye_cascade = cv2.CascadeClassifier('haarcascade_eye.xml')
    
    image = cv2.imread('frame119.jpg')  
    gray = cv2.cvtColor(image, cv2.COLOR_BGR2GRAY)
    faces = face_cascade.detectMultiScale(gray, 1.3, 5)
    
    print len(faces)   # it will print no of faces detected 
    for (x,y,w,h) in faces:
        cv2.rectangle(image,(x,y),(x+w,y+h),(255,0,0),2)
        roi_gray = gray[y:y+h, x:x+w]
        roi_color = image[y:y+h, x:x+w]
        cv2.imshow('face',roi_color)  # It will show a cropped face , if face is detected
        cv2.waitKey()    
        eyes = eye_cascade.detectMultiScale(roi_gray)
        for (ex,ey,ew,eh) in eyes:
            cv2.rectangle(roi_color,(ex,ey),(ex+ew,ey+eh),(0,255,0),2)
    
    cv2.imshow('image', image)
    cv2.waitKey(0)
    cv2.destroyAllWindows()
    

