Some background first......
AGEMA may not be a familiar name to those who have only recently become interested in thermal imaging cameras. They were arguably the designer and manufacturer of the best professional industrial thermal cameras. They were named AGA but became AGEMA. FLIR rcognised the quality of the engineers and products that existed under the AGEMA brand and bought the whole company. FLIR also purchased Inframetrics and the combination of AGEMA, Inframetrics and FLIR (FSI) was a most powerful and effective force within the marketplace. FLIR has continued to aquire companies to improve their products. Indigo being a more recent example of that policy.
AGA/AGEMA had cut their teeth on the earliest of thermal cameras that were dual axis scanners with Liquid Nitrogen cryogenic cooling of the semiconductor detector pixel. Yes I said 'Pixel' singular. A singe Pixel was presented with the thermal scene via a horizontal and vertical scanning mirror assembly The two scanning mirrors created a raster scan. The serial scene information that the pixel produced was then processed and turned into a thermal image for viewing on a monitor. Whist mechanical scanning with mirrors or prisms may sound archaic to some, it was all precision machinery of the highest quality and it worked well. A 128 x 128 pixel thermal image was produced using just one cryo-cooled detector pixel. Focal Plane arrays had not been perfected at that time and there were no microbolometer FPA's.
Development of thermal cameras continued within both civilian and military projects. AGEMA developed the Thermovision 550 that used a Stirling Mechanical Cryo-Cooler to reduce the temperature of the detector array to -196C where it needed to be to operate correctly. The detector was a staring focal plane array and so no scanning optics were involved. The picture quality was simply superb with no noticeable noise. The down side of the 550 was its initial high cost and ongoing maintenance costs of the Stirling cooler. The cooler required a rebuild at 2000 hours of use and the cost was around £5000. Around the same period as the Thermovision 550 was released, there was also a cheaper option for industries that did not need the highest performance available. AGEMA had developed two portable scanning cameras that used a new cooled detector. These were the Thermovision 210 and 510. In the Thermovision 510 the detector was a linear array of 160 Lead Selenide (PbSe) pixels. These did not need to be cooled to the extreme temperatures found in the Thermovision 550 so no Stirling Cooler was required. Instead, a Peltier cooler stack was employed to cool the PbSe pixel array to around -70C. As stated, the array comprised 160 pixels in a linear format. As such the array created the cameras vertical pixel count and a mechanical scanning mirror assembly then created 320 horizontal pixels forming a 160 x 320 letterbox image on the 510's electronic viewfinder. Image processing electronics created a stable and high quality image but it does suffer from some minor banding and contains more noise than the Stirling Cooled 550 camera. It was significantly cheaper to buy and maintain however.
The 510 was a civilian version of a Military target search and observation camera. At the time it was a very effective 'tank killer' as the tanks engines revealed their locations, even when camouflaged. Thermal imaging cameras are a very potent targeting tool in warfare and Military money lead to many of the improvements in the technology. There were 'HOT' versions of the civilian 210 and 510 cameras. These had carefully selected detector arrays and the image processing was tweeked to provide the very best performance that could be achieved. Such 'HOT' versions were for Government use only and could not be supplied to the general public.
A significant disadvantage of the 210, 510 and 550 cameras was the fact that they are not SILENT. As such the noise signature of the camera could identify it to hostiles or lead to detection when in close proximity to hostile forces. For this reason, amongst others, the Military invested heavily in the development of non mechanical uncooled detector arrays. This lead to the VOx and A-Si microbolometers. The BST FPA had also been developed prior to these but it required a mechanical chopper wheel so did not meet the Military noiseless requirement. The microbolometer does create a clunk when the FFC flag operates but this can be dealt with satisfactorily in military cameras.
OK, to my AGEMA Thermovision 510.
I have just received my Thermovision 510 camera and initial testing shows it to be in very good operational condition despite its age. It was originally used in a Technology College where it has obviously been well cared for. I received the camera, its charger, four JVC/Sanyo type camcorder batteries and the user manual. All this was in the original AGEMA carry bag. The camera is pretty rugged but it does have a plastic case to reduce weight. The Military versions had a tougher glass reinforced plastic case. The mechanical aspects of the camera are all mounted onto the cast metal front panel and this maintains the mechanical and optical alignment of the system.
The mechanical and optical block is constructed as follows......
The thermal scene passes through an angled Germanium window of significant diameter. The thermal scene arrives at the horizontally scanning mirror. The mirror moves in an arc and presents the thermal scene to the 168 pixel high PbSe array via a Germanium optical block. The PbSe detector module is contained in a module that is under hard vacuum. The Peltier cooler stage is attached to the array directly and is also located within the hard vacuum.
The 510 uses a parallel 'data' bus from the detector array. this is converted into a standard EIA or CCIR TV video raster format by processing electronics. Field memory is use to reduce flicker. The output of the video processing stage drives a conventional CRT Electronic Viewfinder. Image capture from the 510 is via its EIA or CCIR video output. Such image captures were provided by video recorders, video printers and frame grabbers of the era. There are two onboard memories that can capture a thermal scene for the purposes of comparison.
Well that is enough of the theory, now to the pictures.....
First some pictures of the Agema Thermovision 510, then with it next to the venerable Liquid Nitrogen cooled dual mirror scanning Thermovision 880 and modern FLIR E4 and i5
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