Video Analysis Article
|Back to the main video page.||The Rusty has been performing computerized video analysis for skiers and snowboarders since 1997. These pages are intended to help snow sports instructors start performing computerized movement analysis on their own.|
It’s Time to Do Movement Analysis on Your Computer
If you are a professional ski or snowboard instructor you probably work a lot on improving your skiing or riding. How would you like to improve your movement analysis skills at the same time? Using a computer to help analyze video is the solution. Years ago, it would cost thousands of dollars and was a big headache to get set up. Today it’s cheap and easy. If you have a computer and a video camera you can upgrade yourself to computerized movement analysis for as little as $39. This article will tell you why it is time to start doing movement analysis on your computer and how to get started.
The old fashioned way
You don’t need a computer to do movement analysis. If you are an experienced pro, you can probably see everything you need to see watching video in real time with your camcorder attached to a TV monitor. But if you need slow motion to see what you want to see, watching a short clip on a regular VCR can be awkward. If you have an expensive VCR with a jog/shuttle dial, you can control short clips with ease. Alas, most instructors who start doing movement analysis use regular VCRs and struggle to see the same things their more experienced colleagues are trying to point out to them.
The new way
After attaching your camcorder to your computer, you run a “capture” program and playback the video on your camcorder. You can save your video into one big computer file or break up each run into different files which are then called clips. After a clip has been captured, you switch to the analysis program, open the clip and start analyzing.
The first thing you get when you do movement analysis on a computer is extreme control over slow motion and frame by frame viewing. The number one benefit of this is that you can learn movement analysis skills at slow speeds, then train your eyes to see things at ever increasing speeds until you can spot things in real time (i.e. out on the hill during your lessons). This process is much more efficient than using a regular VCR. You will truly be amazed.
Next, the computer has tools that a VCR does not. Line drawing tools help provide a frame of reference that makes seeing level hands and shoulder alignment a lot more obvious. Angle tools can quantify subtle improvements in angulation that are hard to see. Split screen technology lets you show two skiers side by side (in synch) so that you can easily compare and contrast an “analysis” skier against a reference skier. With reverse imaging, the reference skier can be the same skier. When a left turn becomes a right turn (because the image has been digitally reversed), you can easily compare left turns to right turns because they look the same (except for whatever problem the skier is having). For riders, the reverse imaging capability lets you switch goofy riders to regular. This lets you use any reference clip for any rider (as long as the stance angles are close).
The downside to all this cool stuff is that you need the extra computer gear and that it takes a few extra minutes to transfer video from the camera to the computer. While lots of resorts already have computers onsite, using one for your movement analysis may be problematic. If you bring your own computer to the resort, you’re probably going to need to be able to lock it up. But you can always do your own movement analysis at home.
Can your PC and video camera do it?
Almost any PC less than 5 years old is powerful enough to handle video. Most newer PCs come with a IEEE 1394 (aka firewire) for connecting to digital video cameras. If you have an analog video camera or an older PC, you’re going to need a capture device to get your video into your computer. A capture device can cost from $60 to $170. Go to TheRusty.com web site (see the link at the end of the article) if you need more detailed information about what you’ll need and how to get things hooked up.
Even if you’ve shot video on the hill before, there are a few tricks you should know for getting shots that look good on the computer. When taping, try to keep the skier using up 2/3 of the frame in the viewfinder. If the skier or rider is doing wide fast turns, keep them a little smaller and leave room in the shot in front of them. This is the best tradeoff between keeping the subject in the frame and being able to see detail on the computer screen. Avoid using digital zoom. Digital zoom shots look ok on a TV screen, but they look terrible on a computer. With practice you can tell from the picture quality where the digital zoom stops and the optical zoom starts working. You can extend the range of optical zoom by adding a telephoto lens. Finally, before you start taping make sure that you’ve got the image stabilization option turned on.
The V1 solution and TheRusty solution
Are you ready? Get online and go to http://www.v1home.com/PSIA. Click on the “V1 home” link, then click on the “here” for the V1 Home Premium version. You can even download the software directly from the Internet. You can get a version of the software for free, but the $39 “premium” version has the split screen capability. If you’re not quite ready yet, go to http://therusty.com/video.htm. This site has everything you need to get you started and lots of tips that will have you doing video like a pro in no time.
You can improve your skiing or riding and your movement analysis skills by using computer movement analysis software. You’re only $39 away from becoming a better snow sports instructor. Do it this season.
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