| 1. Definition | 2. Functional Requirements | 3. Syntax | 4. Semantics |
1 Definition
Face Descriptors is a Data Type representing the features of the Face of an Entity.
2 Functional Requirements
The Face Descriptors represent the effect of the motion of the muscles of a human face.
The Face Descriptors Syntax represents the Actions Units of the Facial Action Coding System (FACS) originally developed by Carl-Herman Hjortsjö, adopted by Paul Ekman and Wallace V. Friesen (1978) and updated by Ekman, Friesen, and Joseph C. Hager (2002).
3 Syntax
https://schemas.mpai.community/PAF/V1.2/data/FaceDescriptors.json
4 Semantics
| Header | N1 Bytes | Orientation FaceDescriptors | |
| – Standard-FaceDescriptors | 9 Bytes | The characters “OSD-FCD-V” | |
| – Version | N2 Bytes | Major version – 1 or 2 characters | |
| – Dot-separator | 1 Byte | The character “.” | |
| – Subversion | N3 Bytes | Minor version – 1 or 2 characters | |
| FaceDescriptorsID | N4 Bytes | Identifier of Face Descriptors. | |
| AU | Description | N5 Bytes | Facial muscle generating the Action |
| 1 | Inner Brow Raiser | 1 Byte | Frontalis, pars medialis |
| 2 | Outer Brow Raiser | 1 Byte | Frontalis, pars lateralis |
| 4 | Brow Lowerer | 1 Byte | Corrugator supercilii, Depressor supercilii |
| 5 | Upper Lid Raiser | 1 Byte | Levator palpebrae superioris |
| 6 | Cheek Raiser | 1 Byte | Orbicularis oculi, pars orbitalis |
| 7 | Lid Tightener | 1 Byte | Orbicularis oculi, pars palpebralis |
| 9 | Nose Wrinkler | 1 Byte | Levator labii superioris alaquae nasi |
| 10 | Upper Lip Raiser | 1 Byte | Levator labii superioris |
| 11 | Nasolabial Deepener | 1 Byte | Zygomaticus minor |
| 12 | Lip Corner Puller | 1 Byte | Zygomaticus major |
| 13 | Cheek Puffer | 1 Byte | Levator anguli oris (a.k.a. Caninus) |
| 14 | Dimpler | 1 Byte | Buccinator |
| 15 | Lip Corner Depressor | 1 Byte | Depressor anguli oris (a.k.a. Triangularis) |
| 16 | Lower Lip Depressor | 1 Byte | Depressor labii inferioris |
| 17 | Chin Raiser | 1 Byte | Mentalis |
| 18 | Lip Puckerer | 1 Byte | Incisivii labii superioris and Incisivii labii inferioris |
| 20 | Lip stretcher | 1 Byte | Risorius with platysma |
| 22 | Lip Funneler | 1 Byte | Orbicularis oris |
| 23 | Lip Tightener | 1 Byte | Orbicularis oris |
| 24 | Lip Pressor | 1 Byte | Orbicularis oris |
| 25 | Lips part | 1 Byte | Depressor labii inferioris or relaxation of Mentalis, or Orbicularis oris |
| 26 | Jaw Drop | 1 Byte | Masseter, relaxed Temporalis and internal Pterygoid |
| 27 | Mouth Stretch | 1 Byte | Pterygoids, Digastric |
| 28 | Lip Suck | 1 Byte | Orbicularis oris |
| 41 | Lid droop | 1 Byte | Relaxation of Levator palpebrae superioris |
| 42 | Slit | 1 Byte | Orbicularis oculi |
| 43 | Eyes Closed | 1 Byte | Relaxation of Levator palpebrae superioris; Orbicularis oculi, pars palpebralis |
| 44 | Squint | 1 Byte | Orbicularis oculi, pars palpebralis |
| 45 | Blink | 1 Byte | Relaxation of Levator palpebrae superioris; Orbicularis oculi, pars palpebralis |
| 46 | Wink | 1 Byte | Relaxation of Levator palpebrae superioris; Orbicularis oculi, pars palpebralis |
| 61 | Eyes turn left | 1 Byte | Lateral rectus, medial rectus |
| 62 | Eyes turn right | 1 Byte | Lateral rectus, medial rectus |
| 63 | Eyes up | 1 Byte | Superior rectus, Inferior oblique |
| 64 | Eyes down | 1 Byte | Inferior rectus, Superior oblique |
