Over the summer and autumn of 2015, a G3 study group coordinated by VDMA Machine Vision evaluated requirements and looked into different implementation concepts for machine vision standards for embedded systems. Led by VDMA Machine Vision board member Klaus-Henning Noffz (Silicon Software), the study group aimed to deal with the question of which standards are necessary to prepare the global machine vision industry for the future. Results were presented and discussed at the G3 Future Standardisation Forums in Chicago (autumn 2015) and in Kyoto (spring 2016).
After research and discussion with external experts – including those from the Mipi Alliance, the OPC Foundation, VDMA Industrie 4.0 Forum, and Electrical Automation Community – as well as discussion among players of the machine vision community, the embedded vision study group agreed on the following conclusions:
Standardisation candidate one: Interface sensor board to processing units/SoCs
Many new vision applications and markets will greatly benefit from the advances of system on chip (SoC) solutions – small, low-power processors used in consumer or mobile applications. The focus of the study group was the interface between the SoC and a camera module or industrial sensor with an FPGA. Technology candidates that were evaluated were Mipi, PCI Express, and USB3.
While USB3 generally fulfils the requirement – except for industry-standard connectors for embedded systems – there are still open questions for the other candidates, in particular on a GenICam-compliant software layer. PCI Express will be a major effort since there are no standardised drivers available, while Mipi does not provide a standard transaction layer to software, which might inhibit a vision standard. Because of these open questions, the embedded vision study group was not able to give a recommendation on this topic in 2015, but suggested the G3 investigate further. Since then, the EMVA has looked deeper into the issue and further actions were due to be presented and discussed at the Future Standardisation Forum in autumn 2016 in Liège, Belgium.
Standardisation candidate two: Software API
The existing software standards GenICam and GenTL are generally sufficient for embedded system requirements. However, an extension is recommended in order to cover the increased complexity of data formats and device parameterisation. The extensions are similar to those discussed for 3D cameras, but are more general. The GenICam working group is currently working towards a solution.
Standardisation candidate three: Interface smart camera or vision system to process environment
Embedded smart cameras have to face the upcoming Industry 4.0 challenges in the same way as vision systems in general. Industry 4.0 will enforce factory-wide standardisation and, for communication protocols on the factory floor, more organisation and companies are openly championing OPC Unified Architecture. This opens up the opportunity to make machine vision more accessible to factory automation. The study group recommended developing a machine vision companion specification for OPC UA, and, during Automatica, VDMA Machine Vision and the OPC Foundation signed a memorandum of understanding to develop a machine vision companion specification for OPC Unified Architecture. The OPC Foundation is a community for interoperability solutions based on the OPC communication specifications.
Towards an OPC UA companion specification for machine vision
Camera interfaces facilitate the work of system integrators and promote the use of vision technology. However, a generic interface for machine vision systems on the application or solution level is still missing. The goal of the OPC UA companion standard targets easy integration of machine vision systems and cameras into a production environment and IT systems.
In the smart factories of the future, people, machines, production resources and products will communicate with each other and be interconnected online – if needed, all over the world starting with the customer’s order to quality control, from the shop floor to the boardroom. The resulting data convergence will open up entirely new intelligent production options, in which all objects influence and control each other by means of autonomous data and information exchange.
The smart factory resulting from this will follow a completely new production paradigm; intelligent products will be identifiable and located on the factory floor at any time, and their history, current state, as well as possible manufacturing options during production, are all known. Customised one-off products that are manufactured fast and efficiently will thus become a reality.
For connecting machines, production components and products – as is the vision of Industry 4.0 – easy integration and interoperability are key factors. Norms and standards are of fundamental importance, since they define the mechanisms of cooperation and the information to be exchanged, which is where OPC Unified Architecture comes into play.
OPC UA’s initial focus was the industrial automation market, providing an industrial interoperability standard for horizontal and vertical information integration, from sensors to the enterprise. This has since become the adopted interoperability solution for other markets and domains. Machine and device manufacturers describe their data and interfaces and then configure the security credentials to make them available or keep them protected. Different transport mechanisms are integrated to move data and information for different scenarios both for the shop floor and for cloud solutions. OPC UA technology has already been named the recommended communication technology in Germany’s Industrie 4.0 initiative. The German Federal Office for Information Security (BSI) thoroughly analysed OPC UA data security and published a positive review. Many other organisations have taken advantage of the OPC UA information modelling capabilities, allowing information integration between previously disconnected systems.
More VDMA trade associations are now focusing on OPC Unified Architecture. A VDMA guideline, ‘Industrie 4.0 communication with OPC UA’, is currently being prepared. It is intended to support the mechanical engineering industry in the integration process and provide recommendations for action. The VDMA Forum Industrie 4.0 aims to give a clear endorsement for OPC UA as communication protocol for Industry 4.0, which should lead to lower barriers to small- and medium-sized companies for establishing industrial communication.
Next steps
The task is to define which information, data, functions and services should be integrated into a production network, and to map them in OPC UA. First of all, the machine vision industry – in particular system integrators – has to clarify: what comprises a machine vision system, what are its features, and with what in the process environment does it communicate today and in the future. In a second step, what services does the machine vision system offer, what information will be transferred, and how will this information be presented.
Standardisation only works when many organisations support the effort and contribute. The VDMA is currently building up the capacities needed to support and drive this new standardisation activity. However, even with a new VDMA technical expert, VDMA Machine Vision more than ever depends on its members’ expertise and cooperation.
