The next level: 3D-scanning to 3D-analysing!
We already wrote about the new 3D scanning equipment of InnoSportLab de Tongelreep. But it doesn’t stop there! Up to now, a training was recorded and analysed in 2D. In other words, the swimmers were filmed from one side. The next step? Adding a third dimension to those analyses as well!
Why do we need a 3D-analysis system? With the aid of a 3D system, coaches and scientists will be able to improve the technique of the swimmers even further. Because the swimmers are filmed from almost every angle, a more detailed coaching style could be applied. In addition, new information might be obtained regarding the swimming movement. Small changes in technique could result in a better movement efficiency. Since movement efficiency is a key factor during a swimming race, those extra details might be crucial for gold!
What do we need?
To get a 3D image of a swimmer, a lot is required. First of all, a 3D camera system is needed. Back in 2016, a brand-new floor was installed on the bottom of the swimming pool. The reason? Due to the space between the “double-bottomed floor”, room was made for research equipment, including the 3D camera system. With the 6 cameras, scientists and coaches will be able to obtain a 3D image of the swimmers. But that’s not all that’s needed. Underneath the water surface, only little light will reach the swimmer. This makes it difficult to get a true image of the swimmers, which makes it even harder to analyse the footage. Therefore, a simple reflective marker to highlight prominent body parts wouldn’t do the trick.
The solution? The swimmers will get several “active” markers attached to their bodies. Those markers consist of LED-lights, which “actively signal” their position. This makes it easy to visualize the prominent body parts. When one gets the coordinates of each LED-marker, it’s possible to calculate the exact position of a joint. When one knows the exact position of, let’s say the knee joint, it͛s possible to calculate the knee angles in 3D using a special custom-written software. With this kind of information, a normal training will be elevated to the next level.
All those things sound promising. However, still a lot has to be done before we’re able to analyse a swimmer’s movement in 3D. For example, a 3D analysis requires calibrations. One of the calibrations has to be done in the pool to make sure that the camera images and reality line up. The second calibration is somewhat more difficult. This calibration has to be done outside the water to obtain a standardized posture of the swimmer. This is required to calculate the exact position of the joint centers of the body with respect to the different markers.
But what is the best calibration posture to calculate those joint positions accurately? When a person moves, his or her skin is moving with respect to the joints and markers as well. Because of this, different calibration postures could result in different calculated positions of the same joint. It goes without saying that this would be problematic, since those calculated joint centres are very important to analyse the actual swimming movement. To avoid possible errors, the next study of InnoSportLab de Tongelreep will aim to determine the effect of different calibration postures on the calculated joint centres and marker distances. Want to know the results of this study? Just follow the blog on this site and be sure you don͛t miss a thing!