High-Res Scanner Simulates Automotive Fabrics
DARMSTADT, Germany, Nov. 4, 2011 — Newly developed high-resolution scanners copy objects and fabric samples in just a few minutes, converting them into virtual models with startlingly realistic light effects that will help improve the design of automotive and other products.
When buying a car, some customers are not just interested in its fuel consumption. They also pay attention to the car’s appearance: Interior fittings, seat covers and dashboards are considered for style and luxuriousness. Designers want to know well in advance of production how a piece of fabric will look inside a new car.
The HDR-ABTF scanner captures physically realistic images of materials such as textiles, lit from various angles. (Images © Fraunhofer IGD)
Car models once were manufactured exclusively by hand, but that was time-consuming. These days, cars are developed on computers; to assist with this, designers want processes that generate realistic surfaces such as seat covers. And although computer simulation is faster, it takes time as well: Real-world objects must first be scanned at high resolution and then translated to the virtual world.
Now, researchers at the Fraunhofer Institute for Computer Graphics Research (Fraunhofer IGD) have developed two scanners that capture images of real objects with micron precision and use the data to generate deceptively lifelike virtual images. The first device, dubbed the HDR-ABTF scanner, is specifically designed to capture images of materials such as textiles and leather, lit from different directions, precisely and quickly. Computers then simulate how an object — for instance a car seat — covered in that material will look in changing light conditions. The second device, called a meso scanner, captures high-resolution images of 3-D objects.
“For industrial applications, we need fast and affordable devices with high resolution,” said Martin Ritz, a developer at Fraunhofer IGD.
The meso scanner records detailed 3-D structures of surfaces with great precision.
In the HDR-ABTF scanner, a single-lens reflex camera looks down on an object from above. The material is lit successively by several LEDs arranged in a quadrant arc, so that the surface is lit from different angles and photographed in varying light conditions. The end result is a series of exposures for each light direction, which can then be integrated on a PC to produce high-resolution, high-dynamic-range images. A vehicle designer can then combine the image data with the computer model of a car seat and observe the material’s behavior when lit from any angle. There are similar processes that use multiple cameras and considerably more light sources, but working with the equipment developed by Fraunhofer IGD is both simpler and faster, moving from imaging to virtual model in just 10 minutes.
The meso scanner captures images of small 3-D objects. Conventional 3-D scanners project a relatively coarse pattern of stripes onto an object, and the software infers the shape from the distortion of the stripes. The meso scanner instead projects a much more detailed pattern of black and white stripes onto the target, each of which is just about one-third of a millimeter across. Using a special lens in front of the projector, this pattern is moved across the object with an accuracy of about 1/25 of a pixel or less.
“The meso scanner isn’t just interesting for car development,” Ritz said. “There’s also scope for museums to use it to scan rare exhibits, such as jewelry or coins, with high precision.”
For more information, visit: www.igd.fraunhofer.de
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