16 Reply by joan

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Ollie wrote:

I really like the idea of having the spotlight feature combined with tracking, this would be ideal for highlighting a specific player and show their good/bad techniques. This is the one feature I cannot seem to be able to find in any video editing software (besides the mega bucks versions)

Actually I'm not even sure this feature exists anywhere, even in the mega bucks version as you say smile
Many video analysis packages don't even have an equivalent to a spotlight tool, let alone an auto tracking one… (I don't know about all the applications and their features, so please let me know if you know about an existing implementation, it's always interesting).

Ollie wrote:

that is easily implemented.

Well I expect some sort of complications, tracking from 2D imagery is not that straightforward wink
Can you try the existing tracking feature in your scenario ? Try to attach it to a player and see how long it can successfully track him. What is the most common case of failure ?

17 Reply by Ollie

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Hi Joan,

I haven't tested the spotlight feature in the big video editing applications, I have got as far as reading about how to do it and seems to nearly always involve 2 tracks of the same video file overlaying each other, using a spotlight effect and then adjusting the position of the spotlight frame by frame.

I really don't have the time to do that for what I want.

I did test the tracking tool tool in Kinovea and it managed to follow a players head for a couple of from and then lagged behind the head after a short while. But it tracked close enough that if a spotlight was covering the players whole body it would have held position for at least 2 or 3 seconds. I think that if you could mark keyframes and re-position the tracking spotlight in every keyframe it would be fine.

Of course the cherry on top would be being able to freeze the spotlighted video for a few second, add drawings, let the sequence continue in slow motion  etc. smile

18 Reply by joan (edited by joan 2011-08-04 20:23:32)

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On the topic of tools, several ideas could be mixed together in a bigger scheme:

- Stick figure tool to map body position during performance. (how many joints ? proportions ?)
- Lower-body only posture (to represent knee bending, hips level, used in podiatrics for instance)
- Full body posture
- Profile line (used during squat jump and other tests analysis for example)
- Drawing a stick figure to represent the body during an exercise or stretching position.

All these tools would share a lot of source code. They might all be represented by :
- a set of joints
- a set of segments linking some joints together.
- Constraints on segments ? Hierarchy ? (To be defined)

The idea would be to design a tool family that would work in a generic way for this type of joints+segments tools.
(instead of creating X static tools)

Specs:
- The set of joints, segments, constraints would be described in a text file.
- The user would be able to create his own files to expand his toolbox.
- Everything else like rendering and manipulation of the joints would be handled in a generic way.
- Some all-purpose instances would be bundled by default, like the ones cited above.


Input very welcome on:

- An already existing file format created for this purpose. (otherwise it will be XML with "as simple as possible" syntax)
Todo: look into stick figure animation software, software to design exercises or yoga positions, etc.

- Imagine yourself using such a tool. What do you expect when you drag a joint around ? What type of constraints ?

Thanks

edit: Checking on stick figure animation software. Very interesting usability.