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FAST CONTINUOUS 360 DEGREE COLOR 3D LASER SCANNER
Aiwu Zhang a ’ *, Shaoxing Hu b , Yulin Chen a , Haiyun Liu b , Fan Yang 3 , Jia Liu a
a Key Laboratory of 3D Information Acquisition and Application of Ministry of Education,
Capital Normal University, Beijing 100037, zhangawl63@163.com
b School of Mechanical Engineering & Automation, Beijing University of Aeronautics and Astronautics,
Beijing 100083, husx@buaa.edu.cn
WG 1/2 - SAR and LiDAR Systems
KEY WORDS: 3D laser scanning, Data Acquisition, Multiview geometry, Calibration, Texture mapping
ABSTRACT:
There are many needs for the ability to fast acquire 3D data from environmental surroundings, such as navigation, mapping,
localisation and robot mobility, fire and police planning, urban planning, but the technology for acquiring dense, wide ranging,
accurate 3D data is too expensive to be used widely. A low-cost, 360° continuous scanning, portable 3D laser scanner is presented.
The accuracy of the portable laser scanner was analyzed in detail, and an algorithm of systematic measurement error compensation
was given. On the other hand, a sequence of images was captured by a hand-held digital camera, and then 2D images were fast
mapped on 3D point cloud by a method proposed based-on multiview geometry. The experimental results show that the portable
laser scanner has higher measuring accuracy and better data quality. Its max range of the scanner is 80m, and its accuracy can
achieved 6 mm. The portable laser scanner can measure black objects, it well suit tunnel measurement. The weight of the portable
laser scanner is less than 6kg, it can be installed on unmanned aircrafts.
1. INTRODUCTION
3D laser scanner is a new active remote sensing system
developed in the last ten years, and it can scan thousands of
points to a point cloud of 3D data of the object and be operated
at night. To a certain extent, 3D laser scanner meets the data
demands of some applications such as city planning, fire and
police planning, underground mine measurement, tunnel
measurement, and so on. 3D laser scanners have a huge
application market. Unhappily, up to now, there is still no
homemade 3D laser scanner on Chinese market. The foreign
commercial 3D laser scanner has a high price, the terrestrial 3D
laser scanner is about Y 1,000,000, and airborne 3D laser
scanner is about Y 15,000,000. In this case, we developed a
low-cost, 360° continuous scanning, portable 3D laser scanner.
The portable laser scanner can collect no less than 8000 points
every second to meet the needs of fast acquiring 3D data from
indoor and outdoor scenes, but it only costs about one fifth of
the price of the foreign commercial 3D laser scanner.
In practice, foreign commercial long-range or mid-range 3D
laser scanner manufactures are not too many. There are six
main manufacturers: Callidus, Leica, Mensi, Riegl, OpTech and
I-Site. I-Site does not produce its own laser sensor and the laser
sensor employs Riegl’s. Callidus, I-Site, Mensi and Riegl use
the mirror to complete vertical scanning, which the horizontal
scanning depends on a servo motor rotating to complete, and so
their laser scanner can scan 360°.
Some laser scanners measure distances with the flight time and
some others use a phase-difference method. By computing the
angles the coordinates of the point in the space are obtain, for
example, Leica HDS6000 is phase-based laser scanning. We
employ the flight time method to measure distances from sensor
to arbitrary points on the object surface. As basic scanning
device a time-of-flight 2D SICK laser scanner (LMS291 or
LMS200) is used, and which is combined with an additional
servo drive to reach the third dimension. For our laser scanner
design, accurate synchronization of the laser measurement and
the scanning device is very important, and the compensation of
systematic errors is also a key task. Moreover, we also discuss
an approach to map 2D images from a hand-held camera onto
3D laser points.
The paper includes four main sections: (1) Design of the 360°
continuous scanning, portable 3D laser scanner, (2) Error
correction of the 3D laser scanner, (3) Fast mapping the images
onto the point cloud, (4) Analysis of experimental results.
2. DESIGN OF THE PORTABLE 3D LASER SCANNER
2.1 Structure Design
The key components of the 3D laser scanner are a 2D SICK
laser scanner (SICK LMS291 or SICK LMS200) and a rotating
platform driven by a servo motor.
The line scanning of the 2D SICK laser scanner can form the
two modes with 180 ° and 100 °. The sampling resolution in the
modes can be set at 0.25°, 0.5° and 1°, the max scanning range
is 80m, and the scanning accuracy can be up to mm, the
scanning baud rate can be set at 9600, 19200, 38400 and 500k.
SICK LMS200 or SICK LMS 291 communicates with the
computer by serial interface, whose maximum speed can reach
75 times/sec, but the interior buffering capacity is limted (max:
812 bytes). If we can not output the scans in time, the cache
will be refreshed automatically, so that the part of the data
* Corresponding author.