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Creaform Introduces EXAscan

Published: Wednesday, December 5, 2007 - 23:00

(Creaform 3D: Levis, Quebec, Canada) -- Creaform is proud to present the EXAscan, a third-generation self-positioning hand-held 3-D laser scanner equipped with three high-definition cameras which produce very high scanning resolution and data-acquisition accuracy.

The EXAscan is a self-positioning and truly portable laser scanner that is cost-effective and flexible, as it doesn’t require any additional CMM arm or other external tracking devices. To determine its position in space, the EXAscan uses the cameras to locate retroreflective targets previously affixed on or around the part following a random mesh pattern. The data captured by the cameras is used to create a high-resolution mesh model.

The EXAscan also boasts a revolutionary multiresolution function enabling it to automatically set the optimum resolution level of the data acquired, according to the complexity of surface it is scanning. It is also equipped with a push button enabling the operator to switch between normal and high-resolution scanning modes. Thanks to these features, small pieces, fine details, and even textures can now be captured and reproduced.

The EXAscan brings a resolution of 0.05 mm and an accuracy of up to 0.04 mm, which proves greatly useful for scanning highly detailed or textured surfaces and small objects. It is lightweight and can be easily carried in a case the size of a carry-on suitcase, making it extremely practical and versatile. When using this laser scanner, the operator has great freedom of movements, making it possible to scan pieces of virtually any size, shape, or color.

EXAscan technical specifications

Weight:   

1.25 kg (2.75 lb)

Dimensions: 

172 x 260 x 216 mm (6.75 x 10.2 x 8.5 in)

Measurement: 

25,000 measures/sec

Laser class:

II (eye safe)

Resolution in x, y, and z axes:

0.05 mm (0.002 in.)

Accuracy: 

Up to 0.04 mm (0.0016 in)

ISO:

20µm + 0.1 L /1000

Depth of field: 

30 cm (12 in.)

Self-positioning device
What really differentiates the EXAscan from other laser scanners is its ability to position itself in space without any external reference system.

The EXAscan uses three cameras, four LEDs placed around each of the two largest cameras, a red laser cross, and retroreflective adhesive targets. Unlike conventional reference systems, and because the positioning stickers are actually applied onto the part, the reference system of the EXAscan is directly attached to the part itself, so that there is no need to immobilize the part and that ground vibrations or other disturbances around the scanner will not affect measurement, which greatly improves the accuracy of the scan.

To set the reference system, targets must be affixed onto the object following an irregular mesh pattern, and then surveyed with the EXAscan and gathered into a unique reference system located on the object. The device calculates its position in space in real time via triangulation. Concurrently, the scanner first projects a red laser cross on the part; then, the part reflects an image of the cross that is captured by the scanner’s cameras and used to create a high-resolution mesh of the surface.

All of these steps are possible thanks to VxScan, the proprietary data-acquisition software that powers the Handyscan 3D line-up of laser scanners. VxScan provides real-time 3-D rendering visualization and offers great flexibility and powerful options such as surface optimization algorithms, meshing optimization, and sensor auto-calibration. It is also possible for the operator to control the completeness of the acquisition by looking at the real-time image generated by VxScan directly on the computer screen. The software interface is easy to use and makes it possible to view the acquired surface as it is being scanned.

This breakthrough technology even allows for two scanners to be used simultaneously to scan the same part. One single mapping file (positioning features file) is created, copied, and then opened by a proprietary data-acquisition software resident in two separate computers. Because the coordinate system of the scan is directly linked to the positioning file, using the same file with two scanners generates scans that are in the same coordinate system and therefore correctly aligned in relation to each other.

The true innovation lies in the fact that the EXAscan and the REVscan, as part of the Handyscan 3D line-up of products, are the only truly portable, self-positioning, and hand-held laser scanners on the market. To this day, no other company in the world has been able to match this level of portability, innovation, and advanced technology.

Ergonomics
With every innovation come unique challenges. In the case of the EXAscan, the fact that it would be a hand-held device raised the issue of human ergonomics. Industrial designers and engineers were involved in the project to ensure that the device’s shape would allow for use on extended periods of time without leading to musculoskeletal problems in the scanner’s operator upper body.

From an ergonomic standpoint, the designers first had to deal with the concern of respecting the angle naturally followed by the human wrists and hands when holding up the device in the air while ensuring that the scanner’s line of sight would be aligned and centered accordingly. This brought another ergonomics issue for the designers: They now had to determine the optimum position for the handle vs. the device’s point of aim so that its position would suit the natural angle of the wrist and hand. Lastly, they had to decide where to put the two push buttons on the device to minimize the range of movement required from the operator.

The designers and engineers also needed to ensure proper weight distribution on the device and to make it as balanced as possible, because a significant difference of weight between components could cause a distortion on the assembly and therefore, a distortion of the accuracy measurements.

The real challenge, however, was to find a way to build a light, rigid, and rugged device while complying with all mechanical and engineering specifications. The lightness and rigidity of the materials used were crucial factors, because all the ergonomic features of the device were completely dependant on the lightness of the device. The designers decided to focus on optimizing the shape of the scanner and managed to create a light and rigid internal structure. They also succeeded in reducing the number of contact points with the casing to a single one, therefore creating a shock-resistant device and ensuring the accuracy of the data as well as the protection of the optical assembly from shock-induced decalibration.

Upon completion of a thorough review of the different materials available on the market, designers were able to elect the materials most suitable for the scanner’s casing and inner components. Given their extra-versatile nature, light metals and plastics were chosen for the casing as well as for numerous inner components.

Thanks to the commitment and expertise of the industrial designers and engineers involved in this development project, Creaform was able to manufacture the most lightweight and accurate truly portable self-positioning hand-held laser scanner ever made.

For more information, visit online at www.creaform3d.com.

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CMSC

The Coordinate Metrology Society (CMS)—presenter of the Coordinate Metrology Society Conference (CMSC)—is comprised of users, service providers, and OEMs of close-tolerance, industrial coordinate measurement systems, software, and peripherals. The metrology systems represented at the annual CMSC include articulated-arm CMMs, laser trackers, laser radar, photogrammetry and videogrammetry systems, scanners, indoor GPS, and laser projection systems. The CMS gathers each year to gain knowledge of the advancements and applications of any measurement system or software solution that produces and uses 3D coordinate data.