| 摘要 |
The invention relates to a series of security documents, preferably bank notes, comprising several denominations each representing a different value, provided with a watermark in the form of a bar code (2), the bars for each denomination being at another angle to an axis. Additionally the invention relates to a device for detecting and reading a watermark in the form of a bar code, provided with at least two recording elements, two recording elements being sensitive in different wavelength ranges in the infrared range. <IMAGE> |
