Annotation -- Whole body posture |
General definition posture: A posture represents the general alignment of one or a set of articulators (head, trunk, arms) to a particular resting configuration, which shows periodic changes known as posture shifts. Posture shifts (labelled as posture transitions) are movements associated with positioning the body.
Postures are different from actions because a) postures are less subject to frequent change and thus have larger durations, b) postures are robust (small movements do not change or distort the posture), c) whereas actions may or may not be displayed, the body is continually in one or another postural alignment. This means that when a body part is not involved in an action, it is always in a particular posture (but not vice versa, see remark below).
Whole body posture units (-PU) represent postural movement of the whole body caused by articulation of the lower body, but the articulators that are responsible for the movement, i.e. hips, leg and/or feet, are not specified. Whereas only the upper body moves in trunk articulation (leaning, rotation), these categories involve leaning behavior or actual displacement of the body caused by the lower limbs. Whole body posture units are defined for each direction (e.g. left, right) separately. Direction is coded using an anatomical frame of reference, which is independent of any external observer. The direction of the movement is respective to three orthogonal planes that are defined relative to the anatomical standard position of the body (following kinematic standards). The direction coded for postures (e.g. whole body lean to left) refers to the end position. <#comment>#comment>
Segmentation rules: A posture unit (-PU) is segmented in a transition and configuration phase. The posture transition phase (-PT) (posture shift) is the time segment where the articulator performs the movements for obtaining the end position. During the configuration phase (-PC) the end position of the coded articulator is maintained for the coded direction. This does not imply the obtained posture is static.
The transition onset is the starting point of the movement needed to achieve the end position, or the starting frame of the video when the movement onset is cut off. The transition offset is the time point where the transition described in the particular category is ended, or the last frame of the video if the movement offset is cut from the video. The frame following the transition offset is coded as the onset of the posture configuration. The offset of the configuration phase is the time point when the coded end position is broken off by the beginning of a new positioning movement or by an action behavior of same body part. Note: the transition phase can overlap with the retraction of an action. Remark. Not all action behaviors interrupt an ongoing position. It is thus possible that a position of a body part (e.g. head forward) is not broken off by an action by that body part (lateral head shake). When the end of the posture is cut off by the video boundary, the last frame has to be coded as the offset.
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BF-PU
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Whole body moves or leans towards a forward position. The whole body, including the lower part (hips and legs) moves or leans forward relative to the anatomical standard position. |
BF-PT
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Transition phase of whole body moves or leans towards a forward position. |
BF-PC
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Configuration phase of whole body moves or leans towards a forward position. |
BB-PU
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Whole body moves or leans towards a backward position. The whole body, including the lower part (hips and legs) moves or leans backward relative to the anatomical standard position. |
BB-PT
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Transition phase of whole body moves or leans towards a backward position. |
BB-PC
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Configuration phase of whole body moves or leans towards a backward position. |
BMF-PU
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Whole body moves or leans towards the frontal middle position. The whole body, including the lower part (hips and legs) moves or leans forward or backward towards the standard anatomical position. |
BMF-PT
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Transition phase of whole body moves or leans towards the frontal middle position. |
BMF-PC
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Configuration phase of whole body moves or leans towards the frontal middle position. |
BL-PU
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Whole body moves or leans towards a left position. The whole body, including the lower part (hips and legs) moves or leans towards the left relative to the anatomical standard position. |
BL-PT
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Transition phase of whole body moves or leans towards a left position. |
BL-PC
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Configuration phase of whole body moves or leans towards a left position. |
BR-PU
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Whole body moves or leans towards a right position. The whole body, including the lower part (hips and legs) moves or leans towards the right relative to the anatomical standard position. |
BR-PT
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Transition phase of whole body moves or leans towards a right position. |
BR-PC
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Configuration phase of whole body moves or leans towards a right position. |
BML-PU
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Whole body moves or leans towards the lateral middle position. The whole body, including the lower part (hips and legs) moves or leans left or right towards the standard anatomical position. |
BML-PT
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Transition phase of whole body moves or leans towards the lateral middle position. |
BML-PC
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Configuration phase of whole body moves or leans towards the lateral middle position. |
Annotation -- Whole body posture |