The angle of Out-of-plane rotation (face pitch and yaw) must be from -30±3 to 30±3 degrees.
The angle of in-plane rotation (face roll) is not restricted. The face detection algorithm can detect a face in any rotation in a roll and adjust for it automatically. Avoid photos with a face roll angle greater than 45.
The minimal distance between the eyes (interpupillary distance) of the subject: is 60-80 px.
For mobile platforms, the minimum face size (depending on the pipeline) is 192-224 pixels in any dimension, and the face should take up at least 25% of the image. The minimum face size for desktop and webcam photographs is 350 pixels, and the face should take up at least 15% of the image.
Image must have only one face.
Face must be fully visible without any blockage.
The faces should have enough padding (3-25 pixels) around it.
Avoid wearing sunglasses.