1

(3 replies, posted in General)

HI there,

let us assume you placed your cam orthogonal to your plane of motion, and that your subject will be running on that plane in your footage. Let us further assume your cam's lens distortion is negligible.
Using a bottle as shown in your pic is OK, as far as you are not aiming to achieve the highest precision possible when measuring your stride length. Consider the definition of stride length & do not confuse it with step length - former is defined as distance covered from touch-down to touch-down by the same leg, the latter as the distance covered from touch-down of one foot to the touch-down of the other. However, if you are about to key in the value in some wearable device, double-check the definition of the manufacturer.
Still, imho, the best would be for you to place a box of known height & width at the edge of the white line & take a snapshot before the actual running record.
Then, when you are up to do the analysis, you can select the calibration grid, drag & drop it's edges onto the edges of the box, right-klick, key in the dimensions & confirm calibration.
Save your calibration as .kva & load it onto your running records (if you have performed several of them).
Why the grid but not the line? Because if your bottle is not perfectly aligned to the center of the cam (which seems to be the case on the pic), you will have a perspective error affecting the distance measured. If you use a box at the line, the calibration grid will correct for that, so you can measure not only distance but also angles with reasonable precision.

I invite everyone to check this tutorials:
https://www.youtube.com/watch?v=upNY9cM … mp;index=2
Just check the whole section on 2D video analysis by BiomechanicsMMU.

Hope it helps.
Best,

2

(3 replies, posted in General)

Hi there,
it is quite easy or hard to answer your question, the way you formulated it.
Besides the fact that any encyclopedia will provide one with sufficient definition of "calibration" and therefore explain the purpose thereof, the use of "search" function on Kinovea forum will yield 69 hits to provide the person seeking with a closer understanding of Kinovea "calibration" function.
Why do you ask yourself the question on calibration?
To correct an angle? To measure the distance between objects in your video? ...?
best regards,

I can reproduce Amus's problem with 0.8.27 x64, same issues encountered when merging two videos in one.
Did not matter whether originals were .avi or .mp4, did not matter whether the files where sampled at the same or at different frame rates.
Best,

4

(4 replies, posted in Bug reports)

Widely used (in biomechanics) are Dempster's segment endpoint definitions & Dempster's body segment parameters (yes, also center of mass).
Both are summarized here: http://health.uottawa.ca/biomech/course … mpster.pdf
Will check the literature on joan's last post.
Following the gut feeling, isolated movements taking place in one plane & recorded with aligned/calibrated setup might be arguably approximated for such analyses.
If you are aiming at research grade inverse dynamics results, 3D kinematics/kinetics measures remain the gold standard...
For everything else, joan provides Kinovea big_smile
Best regards,

Dear siton,
amazing!
Thank you for sharing!

Correct me if I am wrong, but one possible scenario (someone using already?) would be

- sample .avi video
- run through OpenPose with your .kva output script
- open .avi & .kva in Kinovea
- use the linear / angular kinematics tools for analyses (am I taking shortcuts here?)
- export / use results for ...

have to consider accuracy, though... but it looks really awesome

6

(33 replies, posted in General)

joan wrote:
getpa wrote:

detected issue nr 1: win32 Version has no support for the PSeye. (V26 win32 has no issues there)

I can't reproduce this at the moment. I can still see and open the PSEye camera on the win32 version (definitely not working on the x64 version as the driver is win32 only).

Do you not see it at all or do you see the "No camera found" placeholder image from the driver?
Can you check the log and search for "PS3Eye" to see if there is any error related to opening but not being able to connect to the camera?


Dear joan,
the PS3Eye was not displayed in the cam list at all.
I did a clean new re-install of V0.8.27, this time the win32 version after x64 version installation.
Everything works just fine now - no issue with PS3Eye observed anymore.
Have two of them running in parallel at 75fps without frame drops.

THX for your reply & best regards,

7

(33 replies, posted in General)

Dear joan,

...amazing!

THX a lot, will use as of now & post any bugs detected.
Best regards,

detected issue nr 1: win32 Version has no support for the PSeye. (V26 win32 has no issues there)

Hi joan,
first of all, thanks a lot for your quick reply!
I have to apologize for not being precise in my post above.

"IP Webcam" - check
Kinovea 0.8.26 x64 - check

Now the settings I used today:
IP Webcam video settings - left untouched, .mkv format is pre-defined.
Kinovea settings - Capture > General > Display synchronization > "Camera frame" AND Capture > General > Video format: MKV (not sure wether it was pre-defined here).

Used WiFi hotspot on the phone, connected the PC to it.

Followed the same steps you described in your post - it worked fine for both now, browser & Kinovea.

The only difference to my previous trial is... I closed the browser window this time before opening stream in Kinovea.

tongue

Thanks a lot, once again!

Hi there,
sorry for reviving the topic, but I am up to try the same setup which won't work.
I use the IP cam app for Android on my phone & have a clean stream in the browser, but Kinovea is always returning the error during connection test.
I followed joan's hint & set the display sync strategy to camera frame rate, and tried to stream in mp4, mkv & H264 formats...
I was wondering whether the "http://192.168.0.45:8080/video" extension at the end is appropriate?
Is there anyone using a similar approach & can give a short HowTo here?
Thanks a lot in advance!
Best to all,
getpa

Dear Raphael,
C922 works fine if set the way joan described in his post! I use it with the latest x64 Kinovea version.
It works well even with "suboptimal" light conditions.
If you are looking for something else, give Logitech Brio a try.
There is another recent post in the forum on Brio with more information.
The PS3Eye is indeed not up-to-date anymore, though I am still using them in a very special set-up that cannot be realized with other cams.
Good luck!

Hi murray,
having replied to your post, I went on to use my c922 pro more frequently.
Unfortunately, and I do not know the reason yet (made quite some changes to my hard & software setup since last usage of that cam), most of my records at 60Hz fail now.
Hence, please be cautious and see for yourself, before ordering several pieces of them - just wanted to forewarn!
Maybe other forum members have experienced the same?
Someone?
best,

12

(14 replies, posted in General)

Dear joan,
thank you very, very much for this wonderful piece of software.
Looking forward to using it as of now!
Any bugs (or unexpected features ;-) will be communicated.
Best regards,

Hi murray,
I bought a Logitech C922 Pro, wich is capable of 60 fps at 1280x720 image size.
It works fine for me using different recording software, the record quality is very nice.
It works every now & then using the Kinovea software for recording, e.g. sometimes the records are fine, but sometimes the real fps is much lower than 60 fps.
I have not tried yet to combine two or more of them in any software.
Regarding the distance to cover, just make sure you use an active USB extension cable (up to 5m) or an USB3 port multiplier with external power supply. I am using the combination of those for my 4xPS3eye (enchanced with varifocal lenses) setup.
Best regards,

14

(44 replies, posted in General)

Dear Joan,
when saving the analysed video files, the option to apply the slow motion on the video is not available anymore. This happened on purpose or is this something that went wrong?
best regards,

15

(44 replies, posted in General)

Dear Joan,
just experienced the following issue & would like to inform you:
having installed the 0.8.25 version x64.exe, i cannot access the PS3eye camera anymore - it is not even appearing in the cam list.
With the win32 version, however, I can still access & work with the cams as previously.
best regards,