High speed bottle inspection with EyeSpector smart camera system
rong>Inspection of 30 bottles per second – a case study
When it comes to the food industry the necessity to thoroughly inspect all products, even the cheap ones, is constantly increasing. Nowadays it is inevitable to refit even old facility with modern inspection technique and therefore meet the increased demand for food inspection. Due to the fact that it was not intended to build in an additional processor within these systems, smart cameras are the optimal choice for refitting.
Besides the sensor, the camera body also includes the complete evaluation unit and the software for image processing. As for the EyeSpector systems by EVT, the mechanical engineers have the advantage that they can use the same software that they already know from the PC technique. Thus there is no need for further trainings for the staff and they can start working immediately with the new smart camera system.
In this concrete use case the projects definition was already known from the standard facilities. The task was as follows: At the process of filling beverage bottles it should be ensured firstly that the bottles were filled sufficiently (filling level). And secondly it should be evaluated if the appropriate bottle was used and at the same time if the cap is screwed on correctly.
To meet the variance of all the different products in the various bottling plants and their products, a colour camera, which also is up to difficult inspection tasks, was used. In most of the use cases a greyscale would be sufficient, but especially with difficult products such as a bottle with a dark liquide and a label which is partly in the space were the filling level inspection should take place, the only possibility to tell apart the label from the liquid is the evaluation of the colour. Only by this the areas can be separated correctly.
Surely it also would have been possible to offer several different systems. But those would have complicated not only the sales department but also the maintenance. The facilities, which were to be refitted with the inspection technique were spread all over the world and therefore it would have been necessary to have a delivery and an backup system of both units. Thus the path to use only one colour camera system was set, because the additional costs for a colour camera were decidedly lower than would have been the costs caused by double logistics.
So the only thing left to clarify was, if the processing power would be sufficient for colour images. Because due to the colour the processing power needs approximately three times more disk space and for the evaluation of the colour images one also needs approximately three times more processing power. Due to the fact that smart cameras are quite limited in their size by the camera body, the processing power also is not that much either. Further more the waste heat, which is generated by the electronic has to be lead away by the camera body.
A signal processor by Texas Instruments, which additionally features due to the high processing power one of the lowest heat development, is used for the EyeSpector systems. The processor with 1 GHz reaches a maximum performance of 8.000 MIPS and therefore has enough computing power for the colour evaluation as well as for the necessary measurement technique, even at the speed of 30 bottles per second. The system has an integrated I/O - based on 24V technology - which is connected directly to the machine control. The camera works with 24V and therefore a separate power supply is not needed. So the camera can powered directly from the PLC power supply.
The programming of the software is carried out completely graphical with the drag-and-drop function. As already mentioned above, the programming of the EyeVision software for the EyeSpector systems is identical to the programming of PC systems and therefore the staff does not need an additional training and the change from EyeSpector systems to PC systems is quite easy, because the graphical user interface stays the same.
Furthermore via the built-in web server of the software the end user can create a simple configuration mask for the web browser. Hence the web browser only displays the relevant adjusting values as well as the evaluation image. In case the system is connected to the intranet or internet the configuration can be carried out from any workstation with a web browser.
Depending on the machine in use, you can use either Ethernet or RS232 for the communication with the system control. Thus when it comes to a product change, the control can select the inspection programs automatically, so that there is no need for the plant operator to interfere. The consistent possibility to operate the software by remote control allows that even this “intelligent sensor” can be provided for the latest machine with touch panel handling. In this case all software configurations from the software of the plant can be used and approached as integral system components.
The low thermal power loss allows the application of the systems also in hot regions, such as e.g. Brazil, without an additional cooling. The heat dissipation via the camera body is sufficient.
In summary, it should be mentioned that for the image processing it would be possible to inspect e.g. the fill level of 30 bottles per second, but till now the filling process does not allow a higher speed than 20 – 25 bottles per second.
But the EyeSpector systems keep up with the latest development.