Fitting Feet Better Using Photonics
Buying shoes for kids is common and usually challenging. It is common because children grow fast and frequently need new shoes, and challenging because they do not always sit still.
Now infrared-based photonics gear developed by the defense and security technology company QinetiQ Ltd. of Malvern, UK, promises to make the task easier. The company’s device — called the FootSee — rapidly measures the dimensions of both feet at the same time with great accuracy, even with socks on. Amanda Turner, the company’s product director for the technology behind the device, noted that the length determination is very accurate. “The measurement is ±1 mm.”
Shown is a three-dimensional foot map created using technology adapted from bomb disposal robots. The system projects a mesh of infrared dots onto both feet at once, and an array of six cameras detects the reflections and constructs a 3-D map. Measurements can be performed quickly, with or without socks on, and in standard room lighting. The system is being rolled out at retail stores to improve the fitting of children’s shoes. Courtesy of QinetiQ Ltd.
The system already is in hundreds of stores operated by a UK retailer, and it soon will be in 30 stores in the US that are operated by The Stride Rite Corp. of Lexington, Mass. The collected electronic measurement data, which does not contain personal information, will enable the shoe companies to track trends in foot size and shape. Such data could be useful in shoe production, noted Stride Rite’s senior vice president of retail operations Jay Nannicelli. “That helps us in the development and design of our footwear.”
The device uses neither a multiple camera imaging setup nor a laser ranging scanner. Instead, QinetiQ adapted a 3-D camera technique developed for bomb disposal robots. Such robots must gauge the location and size of an object accurately.
The foot measurement solution involves LEDs operating at 880 nm and acting as a light source for a projector that sends out about 5000 small dots in a regular array over a 30° field of view. Invisible to the eye, the dots bounce off the surface being measured, and a CMOS camera system produced by Melles Griot (now CVI Melles Griot) of Carlsbad, Calif., captures the reflections. From distortions in the array, a software algorithm creates a 3-D map of the foot.
With six cameras — three per foot — the device provides complete measurements. For each foot, one camera images the instep while the others perform a more conventional scan, resulting in acquisition of the length, width and girth of both feet. Besides the array of dots, the cameras capture a visible image that can be combined with the infrared data to create a complete picture.
Turner noted that, although the system will not work in bright sunlight because of the amount of infrared noise, it is robust in standard room lighting. “It doesn’t need a darkened room and works equally well for bare feet or feet wearing any color sock.”
Although the current focus is on fitting children’s feet, the same technology can be applied to other markets and to various parts of the body. Potential applications include shoes for sports and outdoor activities. Taking measurements for fitting helmets and other headgear is another possible use.
These new applications may require tweaking and adjustment of the technology; for example, the density of the projected dots may require adjustment for diverse tasks.
Contact: Amanda Turner, QinetiQ Ltd., Malvern, UK; e-mail: firstname.lastname@example.org.
- The technology of generating and harnessing light and other forms of radiant energy whose quantum unit is the photon. The science includes light emission, transmission, deflection, amplification and detection by optical components and instruments, lasers and other light sources, fiber optics, electro-optical instrumentation, related hardware and electronics, and sophisticated systems. The range of applications of photonics extends from energy generation to detection to communications and...
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