| 摘要 |
<p>An apparatus and method are disclosed which use fluorescence to measure the stress in the walls of glass containers. A laser (40) generates a linearly polarized light beam (42, 46) which is directed into the side wall (32, 36) of a glass container (30). As the beam (46) passes through the side wall, the polarization characteristics of the beam change, generating fluorescent light having a polarization component at each point along the beam (46) in the side wall. The fluorescent light exiting the side wall is processed by a quarter wave plate (52), and by a polarization rotator (54) which alternately modulates the polarization state of the linearly polarized portion of the fluorescent light. A CCD camera (60) acquires images of the modulated polarized portions. The camera images (64,66) are processed to produce a normalized difference image (68), which is acquired by an image acquisition module (70) for analysis to determine the stress in the side wall of the container (30).</p> |
