Face detect and crop by using OpenCV

face_cropper.py

import cv2
import sys
import os


class FaceCropper(object):
    CASCADE_PATH = "data/haarcascades/haarcascade_frontalface_default.xml"

    def __init__(self):
        self.face_cascade = cv2.CascadeClassifier(self.CASCADE_PATH)

    def generate(self, image_path, show_result):
        img = cv2.imread(image_path)
        if (img is None):
            print("Can't open image file")
            return 0

        #img = cv2.cvtColor(img, cv2.COLOR_BGR2GRAY)
        faces = self.face_cascade.detectMultiScale(img, 1.1, 3, minSize=(100, 100))
        if (faces is None):
            print('Failed to detect face')
            return 0

        if (show_result):
            for (x, y, w, h) in faces:
                cv2.rectangle(img, (x,y), (x+w, y+h), (255,0,0), 2)
            cv2.imshow('img', img)
            cv2.waitKey(0)
            cv2.destroyAllWindows()

        facecnt = len(faces)
        print("Detected faces: %d" % facecnt)
        i = 0
        height, width = img.shape[:2]

        for (x, y, w, h) in faces:
            r = max(w, h) / 2
            centerx = x + w / 2
            centery = y + h / 2
            nx = int(centerx - r)
            ny = int(centery - r)
            nr = int(r * 2)

            faceimg = img[ny:ny+nr, nx:nx+nr]
            lastimg = cv2.resize(faceimg, (32, 32))
            i += 1
            cv2.imwrite("image%d.jpg" % i, lastimg)


if __name__ == '__main__':
    args = sys.argv
    argc = len(args)

    if (argc != 2):
        print('Usage: %s [image file]' % args[0])
        quit()

    detecter = FaceCropper()
    detecter.generate(args[1], True)

Hi sir hope you doing well
i have simulate your code and it is working well your code for crop the face part from the image is very good working with all the images can you give the explanation for the code for the cropping image what logic you have used

How could I make the face cropped image more big?, for example the 2x square size.

hey thanks for this work,
I have a problem with line 19, every time I'll get this error
error: OpenCV(4.1.1) /io/opencv/modules/objdetect/src/cascadedetect.cpp:1689: error: (-215:Assertion failed) !empty() in function 'detectMultiScale'
any idea?

hey thanks for this work,
I have a problem with line 19, every time I'll get this error
error: OpenCV(4.1.1) /io/opencv/modules/objdetect/src/cascadedetect.cpp:1689: error: (-215:Assertion failed) !empty() in function 'detectMultiScale'
any idea?

You need to check that the CASCADE_PATH is the correct path of "haarcascade_frontalface_default.xml".

I got the same error before i correctly located the directory path of the .xml file

hey thanks for this work,
I have a problem with line 19, every time I'll get this error
error: OpenCV(4.1.1) /io/opencv/modules/objdetect/src/cascadedetect.cpp:1689: error: (-215:Assertion failed) !empty() in function 'detectMultiScale'
any idea?

You need to check that the CASCADE_PATH is the correct path of "haarcascade_frontalface_default.xml".

I got the same error before i correctly located the directory path of the .xml file

Thanks, it works.

Hi Sir, i am trying this code but showing this error

detecter.generate(args[1], True)

IndexError: list index out of range

out of range is showing

Hi Sir, i am trying this code but showing this error

detecter.generate(args[1], True)

IndexError: list index out of range

out of range is showing

hii .. you have to run the file using the following command :

"python face_cropper.py [your_image_path]"

here, [your_image_path] is a string which contains the location/name of the image you want to crop, which the code takes as args[1] .. you cannot leave that blank

hey ammm. i am begining pls tell me . how to run this code in spyder now i can import every module but i can't run anything. it tell IndexError: list index out of range

For all having problems use this line from documentation and insert on line 7 (don't need to use CASCADE_PATH now; it will automatically detect the path your filesystem has):
Cascade_path is useful only the places where have you deployed the code remotely i.e Docker container, Cloud Services etc

        self.face_cascade = cv2.CascadeClassifier(cv2.data.haarcascades + "haarcascade_frontalface_default.xml")

Documentation Reference: opencv-Pypi

hey ammm. i am begining pls tell me . how to run this code in spyder now i can import every module but i can't run anything. it tell IndexError: list index out of range

This is a problem with your image, I suggest you compress the image and then run, I had the same issue and compressed the image to <500kB then it worked.