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This paper presents a vision-based on-line level control system which is used in beverage filling machines. Motivation for the development of this sensor system was the need for an intelligent filling valve, which can provide constant filling levels for all container/product combinations (i.e. juice, milk, beer, water, etc. in glass or PET bottles with various transparency and shape) by using a non-tactile and completely sterile measurement method. The sensor concept being presented in this paper is based on several CCD-cameras imaging the moving containers from the outside. The stationary lighting system illuminating the bottles is located within the filler circle. The field of view covers between 5 and 8 bottles depending on the bottle diameter and the filler partitioning. Each filling element's number is identified by the signals of an angular encoder. The electro-pneumatic filling valves can be opened and closed by computer control The cameras continuously monitor the final stages of the filling process, i.e. after the filling height has reached the upper half of the bottle. The sensor system measures the current filling height and derives the filling speed. Based on static a priori- knowledge and dynamic process knowledge the sensor system generates a best estimate of the particular time when the single valve is to be closed. After every new level measurement the system updates the closing time. The measurement process continues until the result of the next level calculation would be available after the estimated closing time would have been passed. The vision-based filling valve control enables the filling machine to adapt the filling time of each valve to the individual bottle shape. Herewith a standard deviation between 2 and 4 mm (depending on the slew rate in the bottle neck) can be accomplished, even at filling speed > 70.000 bottles per hour. 0
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