extend length of limb in 3D

[jutanke]

To annotate limbs it would be good to be able to extend/retract the length of a limb: that means that the "end point" of the limb stays fixed and that the second endpoint will be extended in the already defined direction to the given length.

The limbs on which this should work are:

• upper arm: START (fix): shoulder END (variable): elbow
• lower arm: START (fix) elbow END (variable): hand
• upper leg: START (fix): hip END (variable): knee
• lower leg: START (fix): knee END (variable): foot

The math for this is fairly easy:

import numpy as np
import numpy.linalg as la

start_joint = np.array([x1, y1, z1])
end_joint = np.array([x2, y2, z2])
defined_limb_length = 123.4 # {float}

v = end_joint - start_joint
v = (v / la.norm(v)) * defined_limb_length

end_point_new = start_point + v

[jutanke]

@Belberus @beapc18 how much effort do you think this would be: it would be a real help and I would say this task has to be prioritised

[Belberus]

So it would be just like:

• Click the END joint you want to extend
• Input the target length/length to add
• Modify the END joint

If it is only that, it is not complicated. We can probably do everything in the frontend and finish with an Update to the server.

[jutanke]

The problem with doing that in the frontend only is that you need 3D information. Is 3D information available to the frontend?

[Belberus]

Yeah we keep 3D information in the frontend.

[jutanke]

well, that makes it easy then. So do all of it in the frontend :)

However, it would be nice if the length is a fixed entry per person. It has some "default" value (maybe 0) and once it is set it will be the same during the entire dataset

[jutanke]

I would say the easiest way to tackle this is: each person gets additional data entries in the database:

• lower leg length
• upper leg length
• lower arm length
• upper arm length

This values are all initialized to -1 which indicates: not set. Whenever a range is loaded in the frontend, this values are being communicated to the frontend. The visualization and the selection of proper values can be done in the Keypoint Object Editor where the orange lines are edited:

As an alternative they can be put to where the mugshot is now.

When the user changes the values, s/he need to input them via keyboard and press a "save" button for the limbs (or re-use the same save button you have at the moment: whatever is easier).

When the value is -1 and the user attempts to extend/retract a limb a warning should be shown + nothing should be executed.

When the value > 0 the limb should be scaled accordingly (in the frontend only, if possible).

[Belberus]

API requests: updateLimbsLengths -> UID, newLimbLengths, etc || Update the stored values for limbs in the database for that object. getLimbsLengths -> UID, etc || Return the stored limb values from the database.

[beapc18]

Tasks:

• [x] Create get/update methods
• [x] Initialize all poses with -1 in PoseProperties
• [x] Insert new row with -1 when new id is created
• [x] Create index in db