2003 Fiscal Year Final Research Report Summary
Study on High Detection Resolution for Two-Dimensional Bar-Code Detection System
Grant-in-Aid for Scientific Research (C)
|Allocation Type||Single-year Grants |
|Research Institution||Tokyo Metropolitan College of Technology |
WAKAUMI Hiroo Tokyo Metropolitan College of Technology, Department of Electronics and Information Engineering, Professor, 電子情報工学科, 教授 (00249765)
|Project Period (FY)
2002 – 2003
|Keywords||Optical detection system / Laser diode / Collimator / Barcode / Wide-angle condensing lens / High detection resolution|
In these research periods, we investigated high detection resolution for a two-dimensional bar-code detection system (2-D BCDS) with time-sharing laser light emission method, which is essential to make it fit for practical use. Abstracts of the results are as follows.
(1) Development of a masked collimator
A masked collimator system has been newly developed for the 2-D BCDS to improve barcode detection resolution in a 10-cm detection range from 0.4mm to 0.25mm. This system provides high detection resolution while remaining small system size and inexpensive. Detection range for a 3-line 0.25-mm barcode was expanded from 4cm in conventional systems to 10cm in the new system, using masks with a 3-mm hole diameter. The effectiveness of the masked collimator was confirmed from the result.
(2) Study on long detection range due to optimization of an optical system
We found out that an unbalanced masked collimator system using mask collimators with different hole diameters for three laser diodes i
s effective for achieving the deepest depth of focus. The detection range using this mask system was expanded to 12.5cm from the maximum of 10.3cm for conventional collimator systems.
(3) Development of a wide-aperture condensing lens
A wide-angle condensing lens with a 40-mm aperture and a 28.5-mm focal length has been developed to improve the reliability of detection system. The result showed that its detection range was extended to 14.2cm. We also designed a new geometric optical scheme for images of the incident window of light and made the reason for the detection range extension clear.
(4) Study on significant difference between a wide-angle condensing lens and a normal wide-aperture lens with long focal length
We fabricated a detection lens system using a wide aperture lens with a 50-mm long focal length and compared its optical characteristics with that in the wide-angle condensing lens with the short focal length. The result showed that the latter was superior to the normal wide-aperture lens because its detection sensitivity does not decrease, different from the former. Less
Research Products (10 results)