Those events are computed by the LMT software, not afterwards by a BuildEvent python code.

For this event, speed at frame $f$ is calculated between frames $f - 3$ and $f + 3$ (if they do not exist, it is not a Stop event). It is a 6 frames intervals (corresponds to 0,2 s at 30 fps). A Stop event is created for the frame $f$ when calculated speed is smaller than 1 pixel.

• $v \leq 0.17 \enspace px/frame$
• $v \leq 5 \enspace px/s$.

speed[f] = pos.mass(f+3) - pos.mass(f-3)
if speed[f] < 1:
    # create event "Stop" at frame f

[MASS point of one animal is moving toward another animal's MASS point thatis stopped or moving less fast (not rebuild)],

"Approach contact": [Equivalent to an Approach that ens with a Contact. The approach needs to be longer than 3 frames (0.1 s). This event ends at the frame just before the Contact event and lasts the whole time of the Approach event.],

"Approach rear": [Equivalent to a "Social approach" towards an animal that have a Rearing event at the end of the approach.],

"Center Zone": [MASS point is in center zone: $x in [168, 343] "px" "and" y in [296, 120] "px"$ $thick (approx x in [29.5, 60.2] "cm" "and" y in [52.0, 21.0] "cm")$],

"Periphery Zone": [Opposite of center zone, so if MASS point is not in center zone, it is in periphery zone],

"Detection": [Each line in the DETECTION table of the SQLite database where ANIMALID is the corresponding one. Correspond to an existing mask in LMT.],

"Break contact": "Two animals that were in contact are no longer in contact (distance between their borders is higher than MAX_DISTANCE_CONTACT_THRESHOLD (= 30 pixels for mice ~ 5 cm))",

"Oral-oral Contact": "The distance bewteen FRONT detection (head) of both animals must be smaller than MAX_DISTANCE_HEAD_HEAD_GENITAL_THRESHOLD (= 15 pixels for mice ~ 2.5 cm)",