The measurement wand is used by Velogic Studio to capture the location in space of key points on the bicycle frame.
The measurement wand is used in calibration
and bike measurement
processes. This article will help you understand how to get the best accuracy from the wand.
How it works
To use the wand effectively, it's useful to know how the system uses the wand.
The Kinect camera looks for the colours of the green background and the pink triangles. Once it has located the 4 pink triangles (on a green background) it will "project" a line down the middle of those triangles to where it knows the point of the wand must be.
There is more complexity than this, but that's the basic idea.
Tip 1: Let your Kinect camera warm up for 10 minutes before the session starts.
Studies have been carried out on the accuracy of the Kinect camera. One study shows that the Kinect attains maximum accuracy one hour after being powered on, but achieves very good accuracy after only 10 minutes.
Tip 2: Hold the wand by the handle.
Don't obscure any part of the green face of the wand, e.g. by holding it by an edge.
Tip 3: Hold the wand in the same orientation where possible.
If there are any manufacturing inconsistencies with your wand (or you're using a self-printed paper wand, e.g. while trialling), you can minimise the effect of these inconsistencies by holding the wand in the same orientation for all points. This isn't always possible, but for example when taking the tip of the saddle, you can hold the wand vertical rather than horizontal.
Tip 4: Cover the face with your other hand until you're ready.
This will prevent the system from including any frames where the wand wasn't quite in the correct position yet.
Tip 5: Try to make sure the "low midline point" is actually low.
"Low midline" is one of the points captured during calibration. Try to get that as low as possible - e.g on the bottom bottle boss rather than the top one.
Tip 6: Comparison with manual measurement methods
If the bike frame isn't level with the ground, e.g. the rear wheel is on a trainer and the front wheel is on the ground, then the bike isn't level.
Velogic Studio allows for this via calibration - that's what the front and rear "pitch points" are for. But if you're using a spirit level to measure manually, your manual measurements are likely to have a higher reach and lower stack because of the tilt of the frame.