Explain the pose values to me

[MaxwellHogan]

Hey Dude,

Could you elaborate on what the values for Roll, Yaw and Pitch:

Roll: -x to x (0 is frontal, positive is clock-wise, negative is anti-clock-wise)
Yaw: -x to x (0 is frontal, positive is looking right, negative is looking left)
Pitch: 0 to 4 (0 is looking upward, 1 is looking straight, >1 is looking downward)

what is x in this case - is it simply values measured as pixels? what are the min/max?
Why is pitch only measured between 0 to 4?

can you define Xfrontal, Yfrontal to me? or provide some literature for me

[fisakhan]

Roll, Yaw and Pitch are in pixels and provide an estimate of where the face looking at. In case of mtcnn Roll is (-50 to 50), Yaw is (-100 to 100). Pitch is 0 to 4 because you can divide the distance between eyes and lips into 4 units where one unit is between lips to nose-tip and 3 units between nose-tip to eyes.

Xfrontal and Yfrontal provide pose (Yaw and Pitch only) in terms of angles (in degrees) along X and Y axis, respectively. These values are obtained after compensating the toll (aligning both the eyes horizontally).

[MaxwellHogan]

Thanks, someone posed a question on stack overflow which I answered, below is the link if you wish to make a comment or provide a better answer:

https://stackoverflow.com/questions/67283184/count-yaw-and-roll-in-python-head-pose-estimation-mtcnn/67305344#67305344