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High-speed camera provides new perspectives

Barry McNamara
To be fully equipped with the right clubs and accessories for an important round of golf, the cost can easily top $1,000.
For the two members of Monmouth College’s golf team who worked with assistant professor Michael Sostarecz, that’s just a drop in the bucket. The new science equipment they used for a recent project carried a much loftier price tag.
“The entire camera set up – lights, camera, tripod, software, lenses – is right around $30,000,” said Sostarecz. “The trustees were gracious enough to provide some new equipment for the new science building, but before the building gets here.”
Brandon Kemerling ’13, a physics major, and Jared Johnson ’14, who is studying physics and mathematics, chose the project, in part, because it will help them athletically, as well as academically.
“This is like all the ‘Sports Science’ shows on ESPN,” said Johnson. “That’s where we got this from.”
“Even just looking at this helps you work on your swing,” added Kemerling.
What the students looked at were tiny snippets of videos of themselves striking a golf ball. “Tiny” is the operative word since, at up to 15,000 frames per second, there is only so much data that the camera can store.
“It stores memory like a treadmill,” Sostarecz explained. “It captures the previous two seconds of data, but the data before that rolls off.”
Longer videos can be stored on a computer, but those also require a great deal of memory. For example, recording Kemerling in action from backswing to follow through used 3 gigabytes.
“It’s a delicate balance between the resolution, how fast you want to go, how long you want to record, and the light,” said Sostarecz. “We’ve often sacrificed light to speed up the shutter and get sharper images. If the shutter’s too slow, the ball will be blurry.”
The high-speed camera arrived last October and, Sostarecz explained, “The golf ball was one of the first projects we worked on. The way a hard object like that gets flattened is eye-opening.”
In the 15,000-frame-per-second sequence, the impact was captured between eight frames, meaning the club and the ball were together for about 1/2,000th of a second.
By converting pixels to units of distance, Johnson and Kemerling were able to make a variety of calculations, including club head speed and velocity of the golf ball at impact. Johnson learned that the ball speed coming off his club was 143 miles per hour, while Kemerling used his 6-foot-5 frame to generate a 164 mph effort. Both players expressed an interest in being re-tested during the heart of their spring season.
“What they’re doing involves modeling, calculus, physics and differential equations,” said Sostarecz. “It’s an interdisciplinary project.”
“This project has helped me think outside of the box,” said Johnson. “I now understand different ways to calculate pretty much whatever I want to calculate. This project has helped me become more creative in my thinking towards physics and mathematics.”
“I also got some ideas for future projects, possibly hitting a golf ball into glass to observe it at high speed,” added Kemerling.
It’s not only the golfers who are experimenting with the camera, which Sostarecz said features the “same software that is used for crash tests and how air bags deploy.”
By using particle trackers (think the dots on athletes when they are being modeled for video games), Sostarecz was able to conduct a simple experiment shooting balls out of a launcher.
“A solid plastic sphere had the classic parabolic flight,” he said. “Then we shot a styrofoam ball, which is light enough that drag matters. Acceleration is no longer constant, and the sphere fell short of the parabolic arc.”
Sostarecz’s students were able to compare their mathematical predictions of the projectile motion with data from these experimental images.
Sostarecz also used the camera to capture what happens when a ball is dropped into a viscoelastic fluid.
“You can see the colors of stress in the fluid,” he explained. “Different wavelengths of light will refract differently.”
If you think Sostarecz is pleased to have such a diverse teaching tool at his disposal, you’d be “right on.”
“This is way cool,” he said of the camera. “It can be used in a number of interdisciplinary applications. Being able to visualize life in slow motion will give our students new perspectives in the world around them.”
As advertisements for the NCAA often say, Johnson and Kemerling will probably “go pro” in a field other than sports. While they might not earn a paycheck from playing golf, the sport could still be a part of their careers.
“I want to go into some sort of engineering,” said Kemerling. “If I could tie that to possibly designing golf clubs, that would be my dream job. Analyzing golf swings with the high-speed camera – using equations studied in physics – would be pretty cool, too.”
“I hope to become involved in product technology for a golf company or an athletic company,” said Johnson. “I would like to work for Titleist, Callaway, Nike or Adidas.”
In the meantime, if their high-speed camera project helps improve their golf game, too, that wouldn’t be a bad thing. After all, both Kemerling and Johnson were hoping to dethrone the 2010 Midwest Conference men’s golf champ. That just happened to be another student they regularly passed in the hallways of the Haldeman-Thiessen Science Center, physics major and math minor Rodney Clayton ’11.