Inspection device for recognizing embossings and/or labels on transparent vessels, in particular beverage bottles

1. An inspection device for examining the positions of embossings and labels relative to another, on transparent vessels, in particular beverage bottles, comprising:

a camera for imaging in a camera picture an embossing and a label of a vessel to be examined;

a transmitted light lamp provided with a luminescent screen and used for sending light through the embossing to image the embossing in transmitted light at the same time the label is illuminated with incident light, wherein the luminescent screen has formed thereon areas with different luminous densities, wherein there is a gradual change of luminous density between the areas of different luminous densities, the inspection device further comprising a computing unit for determining the position of the embossing and of the label in the camera picture; and

an incident light lamp for illuminating the label to image the label in the incident light.

2. An inspection device according to claim 1 , wherein the areas of different luminous densities are arranged in a strip pattern.

3. An inspection device according to claim 2 , wherein the strip pattern comprises one to three dark strips.

4. An inspection device according to claim 1 , wherein the luminescent screen is arranged outside the focal length of the vessel, so that the vessel acts as a cylindrical lens with respect to the light from the luminescent screen and the distance between the luminescent screen and the focal line of the vessel corresponds at most to twice the focal length of the vessel.

5. An inspection device according to claim 1 , wherein the brightness of the incident light lamp and/or of the transmitted light lamp can be adjusted such that the brightness difference between the embossing and the label in the camera picture becomes as small as possible.

6. A method of examining the positions of embossings and labels relative to another, on transparent vessels, in particular beverage bottles, comprising:

a) sending light from a luminescent screen having formed thereon areas with different luminous densities, wherein there is a gradual change of luminous density between the areas of different luminous densities, through an embossing of a vessel to be examined;

b) illuminating a label of the vessel to image the label in incident light during during sending of the light from the luminescent screen through the embossing, wherein the incident light and the light from the luminescent screen are from different light sources;

c) imaging in a camera picture the embossing and the label of the vessel to be examined; and

d) determining the position of the embossing and of the label, based on the camera picture.

7. A method according to claim 6 , and adapting the color spectrum of the light from the luminescent screen to the spectral transmission characteristics of the vessel and/or the vessel content so as to transmit light through the embossing as efficiently as possible.

8. A method according to claim 6 , and focusing the camera onto the front of the vessel and opening the aperture of the camera to such an extent that an embossing arranged on the back of the vessel is imaged fuzzily.

9. A method according to claim 6 , and emitting the light from a luminescent screen, which is arranged outside the focal length of the vessel, so that the vessel acts as a cylindrical lens with respect to the emitted light and the distance between the luminescent screen and the focal line of the vessel corresponds at most to twice the focal length of the vessel.

10. A method according to claim 6 , and adjusting the brightness of the incident light and/or of the light transmitted through the embossing such that the brightness difference between the embossing and the label in the camera picture becomes as small as possible.