badness on high yaw

[sthalik]

High face yaw causes false positive detections which don't correspond to what's in the image.

Trying to guard against it by guessing yaw and skipping flandmark_detect invocation but it's kludgy and doesn't work anyway.

[uricamic]

Yaw angle with big deviation from near-frontal can be handled by learning new detector, e.g. for full profile and then switching between detector's dependent on the yaw angle estimation.

[sthalik]

Solution I chose is to ignore poses where the model and the flandmark detector's rotation differ by more than a threshold amount.

Critical yaw angle value is problematic to estimate as it depends on pitch too.