Embedded special

MIPI standard Of course €99 could still be considered a high-end price for the embedded vision market – cameras costing $10 are available. But, as Williamson at Stemmer Imaging noted, while the components might be cheap, the development cost to build an embedded vision system is a lot higher. ‘It really only makes sense if volumes are in the thousands or more,’ he said. ‘If you create a custom embedded processor for five products, it doesn’t make


sense because it takes a lot longer to develop than a PC-based system would.’ Plus, in Europe, there are requirements like CE approval, which adds complexity. Tis is why, from a machine vision industry

perspective, a standard for embedded vision is so important, to make it easier to develop embedded systems and to ensure cameras can interoperate with embedded processors. Te EMVA is currently working on a machine vision standard based on the MIPI


interface, which is really a consumer product interface – ARM chips are supplied with a MIPI connection and it is the interface used for cameras on a mobile phone, for example. Allied Vision’s 1 product line includes a MIPI interface. USB 3.0 is an option for building an

embedded vision system, according to Williamson, but USB 3.0 uses processor bandwidth, it doesn’t have direct memory access into the processor. MIPI, on the other hand, has been designed specifically by the processor manufacturers so that the camera data feeds directly into the processor. Te EMVA embedded standard therefore makes embedded systems more compatible with the machine vision sector. ‘Mobile phone cameras

We did some calculations on the break-even point... And yes, we are talking about huge and ambitious numbers

are not machine vision cameras; they’re not asynchronous reset or global shutter, all the things a machine vision system requires,’ Williamson explained. ‘Te cameras that are available to work with MIPI at the moment don’t meet many of the machine vision market needs.’ Te standard is being driven by the machine

LMI’s Gocator 3D sensor approach to measuring cylinder heads in internal combustion engines

Smart cameras from Cognex or Teledyne Dalsa contain embedded processing, and there are now smart 3D sensors available that make 3D vision available as a designated product, with light source and processing all included. LMI’s Gocator 3D smart sensor is one such product. It was introduced in 2011 and has an all-in-one, precalibrated design. LMI’s CEO, Terry Arden, commented: ‘Embedded controllers are not just suitable approaches for processing 3D data, but a necessity for handling the high speeds involved in laser profile

scanning or the high data loads involved in stereo fringe projection. Scan rates can easily get up to 4kHz (laser) or 10Hz (fringe). Data rates can reach 1GB/s. Buffering and transmitting raw image data over GigE, Camera Link, or USB would introduce cost, complexity, and often result in too high a latency before a pass/fail decision can be generated.’

The embedded controllers in the Gocator 3D sensors contain both an FPGA and multicore processors that extract laser or fringe data from raw images, and then convert it to a 3D point cloud

22 Imaging and Machine Vision Europe • June/July 2017

for processing in real time. Arden said that the advantages of embedded 3D sensors are that the inspection system is easier to scale simply by adding more sensors, and that it makes 3D vision easier to use by process control engineers who might not have in-depth machine vision expertise. LMI has just launched a dedicated 3D measurement system for measuring cylinder heads in internal combustion engines. The Gocator 3210 with cylinder head volume checker gives a high resolution 3D scan at an accuracy of +/- 0.04cm3


vision industry. ‘From the Embedded Vision Alliance point of view, they are less interested in standards rather than promoting partnerships to realise solutions,’ Williamson added. ‘Tose in the embedded vision community are interested in collaborating and trying to get people to cross-fertilise technologies. It’s the machine vision sector that’s saying “we need a standard to make the cameras interoperate better with the embedded processors”.’ While the embedded vision market

represents an opportunity for machine vision suppliers, there is the question of how embedded processing will alter factory automation. Most factory inspection systems are still PC-based, something Zalewski feels will largely remain the case, in the short term at least. PCs are more powerful than embedded boards, and traditional systems can be upgraded with additional peripherals much easier than an embedded system designed for a specific task. However, he added that the initial cost of an embedded system is much lower than a classic


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