| 摘要 |
Apparatus for detecting commercial variations in transparent containers (12) such as glass bottles that comprises a light source (14 or 34) for directing diffused light energy through a container under inspection. A light sensing camera (24) is positioned to receive an image of the light source transmitted through the container sidewall. A light control film (20, 36) is positioned adjacent to the light source between the light source and the container, and comprises a plurality of parallel slats (22, 38) spaced from each other so as to limit the angle from which the image of the light source can be viewed at the camera. Commercial variations are detected as a function of variations in light intensity received at the camera. In the preferred embodiment of the invention, first (22) and second (38) arrays of spaced parallel slats are positioned adjacent to the light source, with the slats of the first array being at an angle to the slats of the second array so as to project a moiré fringe pattern through the container onto the camera. <IMAGE> |
