Dlib: Frontal_face_detector returns rectangles with negative coordinates

[itai-icx]

The issue is that frontal_face_detector returns negative coordinates for the faces it detects.
Reproduction code:

import dlib
import numpy as np
from PIL import Image

im = Image.open('<image_path>')
face_detector = dlib.get_frontal_face_detector()  # Face detector
faces = face_detector(np.array(im.convert('RGB')), 1) # Image is RGBA, so convert to RGB
face = faces[0]
print face

And the image used is the one attached below (taken from Google).
This outputs for me [(-37, 23) (260, 290)].

Maybe I'm missing something, but it seems strange to me that it returns negative coordinates.

Thanks!

[davisking]

Yes, you can get negative coordinates because faces can be only party in an image, as your is.