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Automation Technologies 3/2015

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Automation Technologies 3/2015

MACHINE VISION Smarter

MACHINE VISION Smarter inspection system for the beverage industry In the case of the new generation smart camera series, “smart” stands above all for clever functions and a wide range of interfaces for intelligent networking and for integration in control systems. Bernhard Voigt from Voigt Technology e.K. uses the Lsis 400i smart cameras from Leuze electronic to realize smart inspection systems for the beverage industry. Bernhard Voigt, who, with decades of experience in the beverage industry, has specialized in the development of solutions in all areas of process and quality control explains “Inspection systems in beverage filling systems are often highly customized solutions that are implemented between the individual process steps. Often, new control steps are required due to increasing quality requirements or there are extensions to control steps in existing lines.” The range of inspection systems in the field of beverage filling systems ranges from the inspection of empties and full case checks to bottle contour detections, fill-level monitoring, the inspection of caps for incorrect mounting, and label inspections to rejection systems and other similar functions. One of Voigt‘s most recent projects is the equipping of filling lines in the traditional sparkling wine winery Herres, located in Trier, with inspection systems for detecting and checking printed 2D Data Matrix codes on sparkling wine boxes. Voigt uses the sensors from Leuze electronic here as core components – in this case, the smart cameras. The multifunctionality of these smart cameras is the biggest advantage. They have the ability of incorporating all necessary components for image processing in a single device, i.e., illumination, data memory and interfaces, including display for operation and result displays. No additional connection unit or separately installed configuration software is required. The smart cameras and its versions used by Herres are used for quality control (measurement function) and code reading in one device. Horst Meyer, head of engineering at Herres, explains the advantage of these smart cameras: “For code reading, we use the LSIS 462i version, because we already successfully use such devices in other applications, such as for image processing in the scope of cap monitoring. This allows us to limit spare-parts inventory to one fully equipped device model that we can use everywhere if necessary.” About Company name: Leuze electronic GmbH + Co. KG Headquarters: Owen, Germany Turnover: €134 million (as of 2013) Employees: 850 worldwide Products: Switching/measuring sensors, solutions for image processing, data transmission/control and safety

Smart functions The robust design of the smart camera in the metal housing is an advantage for the damp environments of the beverage industry. The smart features of this gerneration of cameras are the motor-driven focus adjustment and the homogeneous illumination developed by Leuze electronic. The motor-driven focus adjustment permits flexibl e use for applications with varying camera distances. Focal adjustments take place automatical ly during program changeover and do not need to be performed manually. This thereby also ensures that the respective, optimum settings are reproduci ble. Also relevant to quality is the integrated illumi nation. Instead of using LEDs as usual, Leuze electronic developed special optics for this purpose. They create a rectangular intense illuminated field of view that is particularly homogeneous at a distance of 50 to 250 mm to the test object. With such images, which have a considerably higher level of detail, image proces sing is better, faster and more re liable. Process reliability with BLOBs The reliable realization of a wide range of monitoring tasks is supported, above all, by the Binary Large- OBject (BLOB) analysis. A so-called BLOB refers to a neighboring area of pixels whose light intensity lies between defined limit values.By setting BLOB parameters, individual objects or object groups can be reliably detected and differentiated. A wide range of criteria, such as area, circumference, shape factor as well as height/width, length, angle and center point, are available for evaluating objects. An area, for example, is the sum of pixels enclosed in a BLOB, even including free spaces within the BLOB if required. The circumference is the length in pixels of the outer contour of a BLOB. The high-performance BLOB detection tool offers the possibility to group together various detection characteristics. Code inspection, process monitoring at the same time The devices are connected via a control unit developed by Voigt that performs the data acquisition and processing as well as the communication with primary system controls. “One key reason for the use of Lsis 462i in the new code inspection stations at Herres is the integrated RS232 interface. With an additional connection box, the data can very easily be transmitted Lsis 462i smart camera: suitable for reading codes and for quality assurance to primary bus systems at Herres this is Profibus. The task of this code read station is to inspect the 2D Data Matrix code previously printed on the cartons for presence and readability. While the exist-ing I/O interfaces are all that is needed for the pure presence and readability, the Profibus interface is required for data transmission to the central computer.” emphasizes Voigt. High speed operation The inspections take place as cartons pass by speeds as high up to 6000 cartons per hour. This is complicated by the fact that the codes are printed at different locations on the cartons depending on the product. “The window in which the codes can be located is, after all, 50 mm high.Furthermore, the codes are also located at different horizontal positions” explains Voigt. Helping here is the so-called reading gate control with which a Leuze elect ronic red-light scanner generates a trigger signal that in turn triggers pulsed illumination and image acquisition until the code is reliably detected. Furthermore, the smart cameras are mounted at such a distance that a large field of view results in which the codes can be detected at every possible height. In addition to the pure inspection for presence and readability, the reference code comparison integrated in the device facilitates calibration to ensure that the printed code is correct. The code read stations offer the option to evaluate certain quality parameters of the read codes. The quality and readability with any other devices can be ensured immediately after a code is printed. During marking, quality characteristics can thus also be detected, evaluated and used for process reliability in order to e.g. perform corrections with respect to the print quality in a timely manner. Photographs: teaser fotolia www.leuze.com AUTOMATION TECHNOLOGIES 3/2015

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