Modern Golf and the Magic of Machine Vision
Jeff Cooper, Vice President of Engineering at aboutGOLF, has more than two decades of experience in the software business, providing automotive and aerospace customers with simulation software for kinematics and dynamics in the Computer Aided Engineering space. He joined aboutGOLF in 2011 with an interest in applying the lessons from these industries to sports simulation and looks forward to the emerging and exciting eGaming market.
aboutGOLF is committed to providing the most authentic golf experience possible in our simulators. To do this, we must understand the science behind golf. I came to aboutGOLF with twenty years of experience in automotive and aerospace simulation, and our engineering team has over two decades of experience with machine vision and the flight physics of the golf ball. aboutGOLF’s expertise in these areas has helped immensely with producing the most accurate golf simulator on the market.
Before I go into detail about why aboutGOLF chose machine vision and how it works, I’ll give you a quick (I promise!) physics lesson so it’s easier to understand why the accurate measurements from machine vision are critical for input to the flight physics and consequently calculating accurate ball flight.
A Quick Lesson on the Physics of Golf
Many factors determine golf ball flight before the club even hits the ball. A person’s swing, the direction and speed of the incoming club face, the physical properties of the club, the lie angle, and even the dimple pattern on the ball will all influence the shape of your shot and where the ball lands. It’s the simulator’s job to calculate the resulting ball flight by measuring three major elements immediately after the club hits the ball: velocity, launch angle, and spin.
Most simulators measure the launch angle and velocity of the ball. These measurements help predict the speed and distance a ball will travel. Launch angles help with the initial direction, but that’s only part of the story. The trickiest measurement is spin, which makes it possible to accurately project the exact curve of the ball while in flight, otherwise known as the shot shape.
The primary rotation of a golf ball is what we call backspin. A club hits a ball and as the ball comes off the club face, the ball spins about an axis. We decompose this spin into backspin and sidespin. For a well struck golf shot, the majority of the spin is considered backspin, resulting in a shot shape that is relatively straight. More commonly, the spin rotation is about an angled axis which creates uneven pressure on either side of the ball. This pressure imbalance is what causes a shot to fade, slice, draw or hook.
If the spin results in a higher pressure on the left side of the ball than the right side of the ball, the ball will curve to the right. For right-handed golfers, that's called a fade or a slice. If there's more pressure on the right side of the ball than the left side, that means the ball will curve to the left, which is called a draw or a hook.
Why Accuracy Matters
If ball spin isn’t accurately measured by the simulator, what you see in the simulator may not match reality. Experienced golfers, who know their game, appreciate when there's accurate measurement and therefore an authentic shape to the shot. If someone is new to the game and training in the simulator, they may not pick up on inaccuracies. It leads to frustration when they golf outdoors and realize what they were "learning" in the simulator doesn't match reality.
Because we not only measure launch angle and velocity accurately but also the spin, our simulator works very well as a training tool.
How Machine Vision Works
Our 3Trak launch monitor contains proprietary cameras. These cameras are highly specialized for tracking high-velocity, high-spin rate golf balls. You can't find an affordable camera on the market that comes close to this camera’s performance. Before you ask, it's not something we sell independently. It’s only included in our simulators.
The most important thing about our machine vision is stereo vision. We position two or more cameras with a very high rate of capture to accurately determine the 3D location of the ball in flight. This is important for capturing the vertical and horizontal launch angles as the ball leaves the ground. The proprietary markings on the ball allow us to measure the exact rotation of the ball surface, which gives us the spin rate. The spin rate has a huge influence on the shape of the shot and therefore the authentic nature of the golfing experience in the simulator.
We do not estimate spin. We measure spin.
Things to Consider Before Buying a Simulator
Experts demand accuracy when using simulators for club fitting. PGA Professionals require precise measurements to improve their own game or enable tailored coaching for a client. If you’re a serious competitor looking for a training tool, accuracy will be a key consideration. It’s important the muscle memory you develop on a simulator translates to a superior game on the course, and you’ll want accurate distances for each of the clubs in your bag.
I’m proud to be part of the aG Team, and I’m excited we apply the engineering rigor proven in other industries, such as automotive and aerospace, to golf instruction. We’ve heard from PGA Professionals a level of frustration with golfers turning to YouTube or magazine instruction to improve their swing. Accurate measurements about your unique swing help you win the game by eliminating the guesswork in improvement.