| 摘要 |
<p>A method of authenticating watermarked paper comprises the steps of transiently heating a first surface (50) of a watermarked sheet of paper (40) using a hot air source (22); forming a thermal image of the watermark (42) using a thermal imager (30); and analysing the thermal image to determine whether or not the watermarked paper is authentic. The evolution of the thermal image with time is a characteristic of the watermark and is dependent on the local thermal mass of the paper in the region of the watermark.</p> |
