python - Django cut and put only the face in the picture field using opencv

Question

This is the first question Django cut and put only the face in the picture field using opencv2

I have some problems
First. It works even when I update it, so the picture gets weird.
Second. The image size is weird because 'ProcessedImageField' works first and 'FaceCropped' works later.

here we go my codes

class Student(models.Model):
    picture = ProcessedImageField(
        verbose_name = 'pictures',
        upload_to = 'students/%Y/',
        processors=[ResizeToFill(300,300)],
        options={'quality':80},
        format='JPEG',
        null=True,
        blank=True,
        default='students/no-img.jpg',
    )
    def save(self, *args, **kwargs):
        super().save(*args, **kwargs)
        FaceCropped(self.picture.path)

def FaceCropped(full_path):
    base_dir = os.path.dirname(os.path.abspath(__file__))
    file_list = os.listdir('student')

    for i in file_list:
        if i == 'haarcascade_frontalface_default.xml':
            face_cascade_path = os.path.join(base_dir, i)

    face_cascade = cv2.CascadeClassifier(face_cascade_path)
    full_path = full_path
    path,file = os.path.split(full_path)

    ff = np.fromfile(full_path, np.uint8)
    img = cv2.imdecode(ff, cv2.IMREAD_UNCHANGED)
    gray = cv2.cvtColor(img, cv2.COLOR_BGR2GRAY)
    faces = face_cascade.detectMultiScale(gray, 1.3,5)

    for (x,y,w,h) in faces:
        cropped = img[y - int(h/4):y + h + int(h/4), x - int(w/4):x + w + int(w/4)]
        result, encoded_img = cv2.imencode(full_path, cropped)
        if result:
            with open(full_path, mode='w+b') as f:
                encoded_img.tofile(f)
                break;

What i want to is When 'FaceCropped' works, only when i create a new model.
So that it doesn't work when i update the model.
plz help me up

question from:https://stackoverflow.com/questions/65950681/django-cut-and-put-only-the-face-in-the-picture-field-using-opencv

Answer 1

I notice that you already had an form_class class AddStudent in your view.py.

class StudentAdd(FormView):
    model = Student
    template_name = 'student/list_add.html'
    context_object_name = 'student'
    form_class = AddStudent

So, you could override your form_class clean method and make sure the FaceCropped function run before form.save().
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