Study on High Detection Resolution for Two-Dimensional Bar-Code Detection System

在这些研究期间，我们研究了采用分时激光发射方法的二维条码检测系统(2-D BCDS)的高检测分辨率，这对于使其适合实际应用是必不可少的。结果摘要如下：(1)掩模准直器的研制为二维BCDS研制了一套掩模准直器系统，以提高条形码在0.4 mm到0.25 mm的10 cm探测范围内的分辨率。该系统在保持系统体积小和价格低廉的同时，提供了高检测分辨率。3行0.25毫米条形码的检测范围从传统系统的4厘米扩大到新系统的10厘米，使用了3毫米口径的口罩。(2)光学系统优化对大探测距离的影响研究发现，采用不同孔径的掩模准直器组成的非平衡掩模准直器系统可用于3个…激光器的长距离探测S更有效地实现了对焦的最深深度。(3)大口径聚光透镜的研制为了提高探测系统的可靠性，研制了口径40 mm、焦距28.5 mm的广角聚光透镜。结果表明，它的检测范围扩展到了14.2 cm。研究了广角聚光透镜与普通大口径长焦距透镜的显著差异我们制作了一套采用50 mm长焦距的大口径透镜的探测透镜系统，并与短焦距广角聚光透镜的光学特性进行了比较。结果表明，与普通大口径透镜不同，后者的探测灵敏度不会降低，因此优于普通大口径透镜。较少

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 collimatorA 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 systemWe found out that an unbalanced masked collimator system using mask collimators with different hole diameters for three laser diodes i … More 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 lensA 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 lengthWe 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