Motion
analysis made easy with user-friendly 3D wand calibration tool and
software |
Image
System's TEMA 3.7 - Wand and calibration software |
How is wand calibration a more efficient means of camera calibration?
Many emerging applications require calibration of multiple synchronised
video cameras for a variety of deployments requiring the ability
to analyse motion such as in biomechanics and sport; securing passenger
safety in the automotive industry, for recording high-speed events
in a research laboratory and many others.
From a procedural point of view, camera calibration is a series
of steps that a user performs to find the camera parameters that
affect the imaging process such as focal length, lens distortion,
position and orientation.
Traditionally, calibration was achieved by means of a calibration
chart or jig which proved impractical for many multi-view scenarios.
However, modern, and more efficient calibration is conducted
using a wand-based system that allows rapid, flexible and
accurate calibration of multiple cameras without having to face
them in the same direction or of having their fields-of-view overlap.
Using a wand
calibration process increases precision and makes the process simpler
and easier.
What is the TEMA Wand Calibration
Option?
The TEMA software platform provides a range of user-configurable,
high-speed motion analysis solutions for industrial research, design,
testing and safety assessment applications.
Originally developed with the automotive industry in mind, the wand
and wand software is ideally suited for crash tests, pedestrian
tests and component testing in 3D. The wand is also perfectly suited
for other applications whether indoors or out doors. Superseding
all traditional 3D preparations (that is: lens calibration and camera
orientation), the wand comes with a simple procedure, 100% automation
and outputs the most accurate and reliable results available.
(left) TEMA calibration wand
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How
the TEMA calibration wand works |
1 |
Position the cameras.
Set the final zoom, focus and aperture and choose camera positions
so that the points of interest on the test object are visible from
two or more cameras |
2 |
Record calibration images
from all cameras by moving the wand in the entire measurement volume
during approximately 1000 frames and using a low frame rate. |
3 |
Set the final frame rate
and exposure time without adjusting or moving the cameras. Perform
the test and make a synchronised recording from all cameras |
4 |
Use TEMA software and
the calibration images to calibrate the system. All necessary parameters
are calibrated and the process is 100% automatic. |
5 |
Use TEMA and the test
images to analyse the points of interest. 3D results are computed
for each point that is tracked by two or more cameras. |
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The calibration can be re-used in future tests
as long as the camera setup is identical
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Features
and advantages |
Quick
and easy |
Capturing calibration
images is easy and processing them is 100% automatic |
Flexible |
Supports measurement volumes
from 1 x 1 x 1m - 10 x 10 x 3m (W x D x H). Supports multiple cameras
|
Camera-independent |
Cameras of any model,
frame rate and resolution can be used together. All image formats
are supported. |
Powerful |
The Wand Calibration computes
all camera parameters simultaneously as well as statistics and tolerances
for the entire system. |
Accurate |
Tolerances from 1 - 5
mm can be reached in crash test environments. The actual tolerance
depends on the camera setup and is computed as part of the Wand calibration |
Materials
and design |
The carbon fibre construction
and the active markers based on LED technology gives a robust, high-quality
wand that can be used for many years. |
No setup
time |
No preparation is necessary
and there is no need to place reference markers or of doing surveys
of the measurement volume in order to calibrate. The Wand records
on pickup. |
Automatic
calibration |
LED technology combined
with a very robust tracking algorithm allows a fast, robust and highly-accurate
calibration process |
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