1 Topic by xavipl_2000 (edited by xavipl_2000 2009-12-20 20:40:17)

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Congratulations for your software. We find it very useful to do technical and biomechanical studies.
At the moment, students from University of Vic (Barcelona) are using it to do the final papers of Biomechanics, Track and field and Volleyball subjects.

We’ve got some interesting suggestions for 2D fixed plane analysis:

1.    Measuring distances in a segment, positioning and ploting initial and final points in different stills.
2.    This distance tool could allow speed calculation too (distance/time, the time would be obtained from the frame value of the stills).
3.    Obtaining the mass centre by using points of a biomechanical model placed over the image (19 points system or other models).
4.    Positioning coordinate axis in any point of the plane.
5.    Obtaining points (x,y) using coordinate axis.

These improvements would allow us and our students to do simple biomechanical studies, very useful for coaching and training.

Best regards

Carles Romagosa, Biomechanics Professor, University of Vic.
Javier Peña, Volleyball and Biomechanics Professor, University of Vic.

2 Reply by joan

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Hi, thanks for the message.

1 and 2 sounds like you are trying to follow point(s), is this right ? In this case I guess the best thing would be to implement speed calculations within the trajectory tool (?).
Currently one may do this by exporting the trajectory data to a spreadsheet application and make the computations there.

Point 3 sounds like an interesting challenge smile

4 and 5. Yes, this also came up in feedback for trajectory tool and was implemented recently (but only for trajectory for now).
I guess when the data export is available for points, lines and angles, the coordinate system setup will have to be moved in a more accessible location…

I'll consolidate all this in the suggestion list when time permits.
"Human model tool" to adjust on the actual person will probably only be implemented during a later phase, with other "complex" drawings though.

3 Reply by metric

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Yes, speed calculations using the trajectory tool would be very useful. It would address the request made in the post about weightlifting bar trajectory analysis.
I was the one who made paulatc aware of the software and I noted at the time that the only thing Kinovea lacked that a weightlifting coach would find useful was the ability to determine bar speed in the app.

There are several other features that could be tweaked to make them more easily usable by a weighlifting coach, but they're very minor and not really worth worrying about. To be able to determine speed through portions of a trajectory (perhaps displaying it at points of interest in a keyframe?) would really make Kinovea a complete solution for a weightlifting coach.

Of course if you do, more weightlifting coaches would start using it and would then request other features, but that's the nature of these things I guess. smile

4 Reply by joan (edited by joan 2010-01-10 00:48:39)

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So, to sum up options… Don't know what will end up in the software but if you have other ideas they are welcome:

- Having a simple visual clue of the speed, without the exact measurements. (ex: circles at each frames (closer=slower), circles with varying size, color coding of the speed, changes in width of the track (thiner=faster), etc.

- Having a small dynamic label with the total distance from begining to current image, and/or current speed, the label would only be visible for the current frame.
Also being able to view the last segment distance at any time.

- Being able to choose among various informations to show for key images. Key image title, total distance from the begining, distance from last point, speed, others ?


Ideally the number of options available would fit in a single configuration page without too much clutter.
(This could be done by identifying group of options that go together and make them available as bundles instead of giving 100% control over the display, wich can cause confusion if not necessary.)

Also, some more thoughts regarding coordinate axis :
- Having a new menu "Coordinate Axis" under "Image" : By defaut it would add a coordinate axis directly on the image, plus an horizontal and a vertical ruler on the sides.
Plus a way to display a complete overlaying grid based on the current coordinate system.
- Being able to change the coordinate axis by direct manipulation somehow. (and dropping the current extra window of the trajectory tool).
- Having the mouse pointer coordinates (in this system) displayed in the status bar.

For speed measurements, the units should be configurable… The distance calibration might be in centimeters or in feet, it may still make more sense to have a speed in Kilometers per hour or in meters per seconds (or even maybe in Knots, or other speed specific unit).
That should probably end up in the general preferences…

5 Reply by Alexander

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If the position of the camera (height, distance) to the center of the 2D-plane could be used, then you could probably use it to trigonometrically automatically correct the distances/speed/angles that are out of this center?

6 Reply by metric

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joan wrote:

So, to sum up options… Don't know what will end up in the software but if you have other ideas they are welcome:

- Having a simple visual clue of the speed, without the exact measurements. (ex: circles at each frames (closer=slower), circles with varying size, color coding of the speed, changes in width of the track (thiner=faster), etc.

- Having a small dynamic label with the total distance from begining to current image, and/or current speed, the label would only be visible for the current frame.
Also being able to view the last segment distance at any time.

- Being able to choose among various informations to show for key images. Key image title, total distance from the begining, distance from last point, speed, others ?


Ideally the number of options available would fit in a single configuration page without too much clutter.
(This could be done by identifying group of options that go together and make them available as bundles instead of giving 100% control over the display, wich can cause confusion if not necessary.)

Also, some more thoughts regarding coordinate axis :
- Having a new menu "Coordinate Axis" under "Image" : By defaut it would add a coordinate axis directly on the image, plus an horizontal and a vertical ruler on the sides.
Plus a way to display a complete overlaying grid based on the current coordinate system.
- Being able to change the coordinate axis by direct manipulation somehow. (and dropping the current extra window of the trajectory tool).
- Having the mouse pointer coordinates (in this system) displayed in the status bar.

For speed measurements, the units should be configurable… The distance calibration might be in centimeters or in feet, it may still make more sense to have a speed in Kilometers per hour or in meters per seconds (or even maybe in Knots, or other speed specific unit).
That should probably end up in the general preferences…

That's a very comprehensive list and covers much more than I'd thought through.
The application I'd seen for weightlifting was to know bar speed and other information at key points throughout the lift, both as freeze frames and as text displayed along the trajectory.
Quite frankly either would be acceptable. Both would be ideal and the other options you mention would be lovely to have available.

Yes, the units should be configurable. Feet/sec and meters/sec are most common units that I've seen for Olympic Lifting.