Compact, economical and easy to use, smart cameras are able to combine image sensing, embedded processing and I/O capabilities in one device. They help system integrators, machine builders and OEMs develop automated visual inspection applications with decreased complexity. Several factors have been listed in smart camera design.
By Fabio Perelli, Product Manager, Matrox Imaging
The small form factor of a smart camera hides somewhat all the components, features and functionalities that it comes packed with, which could mislead you about the complexity that is involved in designing one.
The following are some design considerations for a smart camera that could help you make that important make or buy decision.
Processor – To start with, a good processor capable of handling most vision applications is needed. For example, Intel® embedded processors allow inspections to take place on fast moving lines or perform more inspections in the allotted time.
Housing – An IP67-rated housing is vital for factory floor use. The housing and M12 connectors ensure that smart cameras are dust-proof, immersion-resistant and extremely rugged, essentially right at home in dirty industrial environments. Smart cameras can also be available without the housing as a board set for an even tighter integration into an existing machine.
Lens – A wide range of lenses are available to choose from depending on the application need. A sealed lens cap and an interface for focus adjustment are also required. A dedicated interface for controlling auto focus lens will facilitate setup, use and maintenance by enabling focus position adjustments via an application’s user interface. Varioptic Caspian C-mount auto-focus lens is an emerging liquid lens technology that is being made available for smart cameras at a reasonable price. Varioptic lenses operate through the interaction of two liquids. Unlike a traditional lens where linear, mechanical focusing takes place, the focusing happens directly and almost instantaneously through the intermingling of the liquids.
Image sensors – The market offers a wide choice of monochrome and color image sensors with resolutions from VGA to 5 Mpixels. CMOS image sensors have the added benefit of high readout rates.
RTIO – Real-time I/O is a feature that manages the timing counts and positioning from rotary encoders for interaction with vision and automation devices. This RTIO is handled better in the hardware than the software. If timing counts are handled using software, there is associated variability that is not ideal for many applications. Some camera manufacturers support hardware-based RTIOs that give the means to tightly follow and interact with fast moving production lines and equipment.
Communication protocols – A smart camera needs to communicate using mainstream industrial protocols to work with other automation devices like PLCs and HMIs. Getting the required certification however has cost and time implications. And a pure software implementation of PROFINET is not going to meet the tight timings required for real-time control. In this case a hardware-assisted implementation is necessary. A Gigabit Ethernet interface would also allow the smart camera to efficiently output data including images over factory networks.
Intensity controller – Built-in circuitry to control lighting intensity is a plus. Some smart cameras have a dedicated LED intensity control interface that simplifies the setup and use of the overall machine vision system by allowing the illumination to be regulated via an application’s user interface.
Size – The size of the smart cameras is getting smaller while the feature and performance set keeps expanding. It takes expertise to come up with a small form packed with robust, capable features. Some smart cameras measure just about the size of a person’s palm (75mm x 75mm x 54mm) allowing them to be mounted into tight spaces.
Development environments – A smart camera needs to run different operating systems (such as Microsoft Windows Embedded or Linux), giving developers a choice among prominent environments for their vision application software.
Application development – Last but not the least, a compatible and complete software development kit is necessary for developing the application with a smart camera. An SDK with a comprehensive set of programming functions for image capture, processing and analysis is useful. It takes considerable expertise and many man years to put together an SDK with an extensive set of tools.
Just as smart phones have eliminated the need to carry a watch, calendar, notebook, address book and camera, smart cameras, by combining all of the functions mentioned above take away the need for separate camera, PC, I/O board, light intensity controller, lens focus controller and industrial communication card. They thus minimize the components used for automation. By being a device that is compact, economical and easy to use, they prove invaluable to OEMs.
“We’ve taken feedback and packed the new Matrox Iris GTR with the features that OEMs need to tackle demanding projects within tight budgets,” said Fabio Perelli, Product Manager, Matrox Imaging.
“At SVIA, our goal is to support manufacturers in their efforts to make themselves more competitive through automation using our standardized, flexible, user-friendly, robotic solutions”, said Matthias Grinnemo, Technical Manager, SVIA. “As a long-time user of Matrox smart cameras, we look forward to the new Iris GTR, which is sure to help us further our commitment to helping customers minimize the cost per part produced in their factories.” (Figure 1)
Figure 1 caption: Smart cameras are smaller, faster, cost-effective and ideal for factory automation applications