Moments in Time

Well, I'm pleased to report that I've managed to get the PlayStation Eye (£15) webcam up and running with the Kinovea video analysis package (£0). The advantage of this camera is that it can be run at 60fps which makes it far better for looking at quicker movements.

With this very cheap and cheerful setup I've managed to be able to get the tracking to work fine up to a cadence of about 80-85rpm which is perfectly adequate for my purposes, sample footage below. There is a slowed down version available on YouTube here.

Continuing to play around with this in an effort to be to improve tracking by recording at a higher frame rate. I read quite a bit on various forums about getting this webcam, which allows higher frame rates, working on a Windows PC. My conclusions are below as a step by step guide to getting things up and running, this worked for me. Many thanks to all those who have posted various parts of the solution on various forums, I hope you don't mind things being included here, I thought it would be useful to bring it all together.

1). Download and install the required camera driver, it’s called the CL Eye Platform Driver from: http://www.codelaboratories.com/downloads At the time of writing the current version is 5.1.1.0177. For convenience I downloaded the file to the desktop.

2).Double click the downloaded file to install the driver, you may be asked whether you want the software to make changes to your computer, just allow it to do so.

3). Once installed you will see that the following directory or something very similar has been created: C:\Program Files (x86)\Code Laboratories\CL-Eye Driver.

4). When you initially installed Kinovea (I’m using the current experimental v0.8.19) the following directory will have been created: C:\Program Files (x86)\Kinovea, you now need to create a file using Notepad, which you will save to this directory.

5). Open Noteped and enter the following text into the file:

6). Save this file as cleye.config in the C:\Program Files (x86)\Kinovea directory mentioned above. Alternatively you can download a cleye.config file from this link and save the downloaded file as C:\Program Files (x86)\Kinovea\cleye.config

7). If you create your own file using notepad check that the file is actually named cleye.config and that it has not had the .txt extension added to it by Notepad. If the file does have the .txt extension, rename the file to simply cleye.config To check this you may need to go into Control Panel, Folder Options and select the View tab and ensure that "hide extensions for known file types" is unchecked. This will allow you to see whether there is a .txt extension present.

8). Plug in the PlayStation Eye webcam, it should self install.

9). Launch Kinovea.

10). Open one capture screen.

11). Select the "Select Source" button.

12). Under "configuration" you should be able to set a variety of frame sizes and frame rates, I am currently experimenting with the 640x480 @ 75fps option and it seems to be working well without overloading a USB2 port. Certainly the round markers I am using now change shape far less at higher cadences and appear to be tracking far better but I’ve only just started experimenting. I’ve currently tried some basic angle tracking at a cadence of up to up to 90rpm and it’s working well on the 75fps setting.

13). If you want you can set a frame rate all the way up to 187fps at a frame size of 320x240 but with such a small frame size marker location and tracking is not as easy and there is further degradation in image contrast and colour.

I paid £15 for the PlayStation Eye webcam and this simple setup has allowed me to record at 75fps and is producing perfectly adequate results to allow basic bike positioning. The colour saturation of the images is lower than the previous Logitech webcam I was using but this is almost certainly at least in part due to the higher frame rates in use and therefore the higher light requirement. I’m not bothered about this, it’s not a fashion show!

I've spent a bit more time with Kinovea this evening and I think I've now pretty much got my head around the features I plan to use. I'm convinced that this freebie package will do what I want and is a far better option for me that spending a load of money on DartFish. The package has it's limitations but in all honesty I think they are not truly package imitations but the result of me doing this on the cheap with a little webcam.

I think the disengagement of the tracking "lock" I've experienced is very much cadence related. Filming at 30fps the lock remains good up to about 65rpm and then starts to fail, even with markers. I think this is because the tracking uses colour AND object shape and as the cadence rises the apparent object (marker) shape changes from round to oval as a result of the pedal speed and tracking is lost.

I'm hoping that using the PS3 Eye, if I can get it going, will allow me to film at maybe 50fps (up to the USB2 data transfer limit anyway) which might allow me to use cadences of about 70-75, we'll see. The camera was only £15 so it's worth an experiment.

So, did some initial trial recordings of myself this evening, nothing serious, just experimental, here's the outcome:

I've always found bike positioning an interesting subject though I've never really gone into it in a great deal of depth other than to read about it and watch some DVDs I obtained. I've always rather fancied the idea of doing some video analysis just out of academic interest but the cost has always put me off given that it would really just be something to do as an interesting exercise.

Anyway, recently I decided to investigate this further and looked again at what seems to be the industry standard for this kind of thing, a software package called DartFish. The software certainly looks to do everything you could wish it to, and more, but like all these things it's pretty damned costly unless you are going to be making a living with it.

I continued my investigations and with some help from the Internet community I came upon a package called "Kinovea" and decided to take a look at it. This software is available as Freeware and it's current stable version is v0.8.15, v0.8.19 can be downloaded which has the latest tweaks and tools and folks can provide feedback on how these things work and make suggestions. The key thing about this software is that it is 100% free and open source.

I've been using a VERY basic setup just using an old PC and an attached webcam and I've at least managed to do some basic bike position analysis, just testing it out on Lorena who has been very understanding! My conclusion so far is that this package will provide a basic platform to perform a basic position analysis without going to a great deal of expense at all. The bottom line for me is that this is free and it's certainly a way of getting information in a readily understandable form. To be honest, for me at least, this package will do all I require and means that I couldn't possibly justify purchasing DartFish.

Below are a couple of clips I took this morning showing the kind of information one can extract from the package. This kind of information becomes even more interesting when combined with the power data from the VELOtron, or any other power measuring device. It's definitely been worth investing a few hours in.