This article from Flir Systems explains the advantages of thermal imaging compared with conventional machine vision systems for industrial automation applications where there is a need to monitor for reasons of quality assurance or safety.
Manufacturers are increasingly considering machine vision as a way to gain a competitive advantage and, for many, systems based on infrared technology are proving the ideal choice. These are enabling manufacturers to validate and increase product quality and throughput, minimise waste and improve profitability.
Maintaining quality standards is important as any slip in vigilance can prove costly both in terms of profitability and reputation. A production problem can occur anytime in a 24-hour shift and possibly when the line is minimally manned. Also it is not always possible to see the problem with the naked eye or to quantify temperature variation. For industries such as automotive and electronics production this ability is critical.
While traditional machine vision can see a production problem, it cannot detect thermal irregularity. In contrast, infrared gives much more information to the decision maker. Indeed, for non-contact precision temperature measurement there is nothing to rival infrared. It adds a new dimension to machine vision and is excellent for applications involving non-destructive testing.
Another major advantage of infrared vision is that it requires no additional lighting to illuminate the target scene; it achieves the same quality image day and night. For traditional vision systems, external lighting is a prerequisite and adds to the overall cost. Furthermore, establishing the correct lighting conditions can be time-consuming and the end result is generally temperamental.
Thermal imaging has other benefits too. In addition to being a highly cost-effective method of automating process control and quality assurance it can also enhance operator safety and minimise fire risk.
In steel, oil and gas production, power generation and where combustible material is stored, this ability is particularly beneficial. And to top that, these cameras can also be used for security and surveillance. Speedy return on investment is therefore a natural byproduct of this multiple use.
Flir Systems is an established provider of fixed mounted thermal imaging cameras, models of which are sufficiently small to be installed almost anywhere on the production line. The continuous development of its range has recently led to the introduction of two additional models, the first of which builds on Flir Systems' reputation for designing high-performance infrared cameras for applications where space and weight constraints prevail.
GeniCam provides a generic programming interface for quick and easy set-up. GigEVision enables fast image transfer using low-cost standard cables over long distances. Both protocols make it easy to integrate software and similarly compliant equipment from different vendors. And this considerably extends the camera's scope of application.
Typical uses for the Flir A35 are in open-loop and high-speed applications where quality and control can be governed by thermal contrast rather than accurate temperature measurement.
Image frequency is 60Hz and users can choose the performance that best suits the need; eight-bit streaming of high-contrast, non-radiometric data or 14-bit image streaming suitable for a wide range of real-time vision applications.
The uncooled Flir A35 captures clear image details and small temperature variants in a range from -40 to +550degC with a sensitivity of <50mK. Multiple units can also be synchronised whereby one is configured as the master and additional units as slaves, which is a common requirement for safety applications.
The IP66 specification of this camera enables it to be used almost anywhere to monitor critical and valuable plant for differences in thermal profile that may indicate an impending problem. It provides accurate temperature measurement so that the criticality of the situation can be quickly assessed.
The Flir A310 PT can pan 360 degrees continuously and tilt 45 degrees in either direction, giving operators accurate pointing control while providing fully programmable scan patterns and slew-to-alarm capability. It houses a thermal imaging and a daylight/low-light camera, and incorporates all the necessary features and functions for building distributed single- or multi-camera systems to monitor large areas using standard Ethernet hardware and software protocols.
In common with the entire Flir Systems A-Series range, the two models above can be equipped with a choice of lenses and accessories to customise the cameras for a wide variety of imaging and measurement applications. These include software packages, Flir manufactured lenses, LCD screens and remote control devices.
The Flir A66xx thermal imaging cameras have a cooled indium antimonide (InSb) detector that reduces thermally-induced noise to below that of the signal from the scene being imaged. As a result, these are the most sensitive in the standard Flir A-Series range, able to see minute temperature differences, capture high-speed thermal events, measure temperatures of very small targets and synchronise with other measuring devices.
A big benefit of the InSb cyrocooler is that it enables the Flir A66xx to operate in the 3-5 micron, mid-wave infrared band where thermal contrast is high. This is important because the higher the thermal contrast, the easier it is to detect objects against a background that offers little thermal difference.
The detector produces crisp thermal images at 640x512 pixel resolution with a thermal sensitivity of <20mK. Furthermore, the Flir A66xx cameras also have much higher imaging speeds than their uncooled counterparts; the Flir A6600 supports image frame rates up to 480 frames per second when operating in windowing mode, while the Flir A6650 achieves up to 4175 frames per second with a 16x4 pixel window.
The Flir A66xx cameras use a standard GigEVision/GeniCam interface to transmit both commands and full dynamic range digital video; additional interfaces include a BNC analogue video output.