Evolución del Concepto6. Diseño y Desarrollo Final

Systems for testing thermal imagers are built from at least six blocks: collimat-or, blackbody, rotary wheel, set of targets, PC, frame grabber, software. Blocks of the system for testing thermal imagers were presented and discussed earlier.

There were also presented requirements on blocks of such test systems.

However, any potential user or buyer of equipment for testing thermal imagers should be reminded that total value of such a test system is much more than a sum of system blocks. One weak block reduces greatly value of a test system. Thus, writing detail requirements on all blocks of a test system optimized for specific ap-plications is an expert task. It is quite easy to make an error on details as there are many parameters that are inter-dependent.

Now, we will present several recommendations for potential buyers/users of systems for testing thermal imagers. If these recommendations not implemented then there is a high probability that the buyer will get a costly test system that is not optimal for his applications.

First, it is recommended for potential buyers of test systems to concentrate more on requirements on the test system than on requirements on blocks of the system.

The best way to write safe for the user/buyer requirements on test system is to write a list of required test capabilities of the system understood as a list of paramet-ers to be measured or list of other system functions. It is a common error found in many tender requirements that detail, sometimes not-needed, requirements on col-limator, blackbody, rotary wheel are presented but a detail list of parameters that are to be measured is not presented.

Second, equipment for testing thermal imagers is expensive. Therefore take care that your funds are well spent on equipment truly useful in your work. Manufactur-ers can deliver, or at least should be able, different vManufactur-ersions of the same test system of different measuring capabilities and at different price level. Try to find a version of the test system that is optimal for your needs.

Third, testing thermal imagers is difficult even having good test equipment, par-ticularly for newcomers to thermal imaging technology. Test system shall generate measurement results but cannot automatically and properly interpret these results.

Such data must be interpreted by human users of test equipment who must do this difficult task. We must remember that test results of a thermal imager often depend on imager settings, environment conditions, test equipment parameters etc. There-fore it is recommended to guarantee in the contract some support from equipment manufacturer covering also help in interpretation of test results.

Fourth, buyers of equipment for testing thermal imagers often forget about problem of recalibration of test systems or rather about the problem of recalibration of some crucial blocks. Costs of frequent recalibration of test equipment can be in long term almost equal to the original cost of purchase of this test equipment.

Therefore please check what are recommended recalibration intervals, what is price of recalibration by the manufacturer, and finally, if it is possible to recalibrate the

test system in local conditions. In most cases recalibration of such blocks like blackbody or collimator can be done in local metrological centers assuming that some technical information is revealed by the manufacturer.

Sixth, typical twelve month warranty time is quite short. Extended warranty of-ten means well spent funds as such warranty guarantee full manufacturer respons-ibility in much longer time.

Seventh, you will spend well your time by reading the educational section at websites of manufacturers of test equipment or by reading other available specialized literature. It will be later easier for you to communicate with the manufacturers because you will then know exactly what you need.

Eight, it is possible to built a system for testing thermal imagers by buying some blocks (collimator, blackbody, targets) and developing other needed blocks (rotary wheel, control software, test software). However, it is a risky policy recommended only for technologically advanced scientific/manufacturing centers with deep knowledge of metrology of thermal imaging. Probability of commercial losses due to long time needed for development of such a combined test system, and due to possible technical problems, is high in most cases.

Ninth, systems for testing thermal imagers offered on international market by different manufacturers are generally similar. The differences are created by small technical details. Some of these details are very important: main test capabilities (number of parameters that can be measured) or other system capabilities (accepted standards of output electronic images from thermal imagers, boresighting capabilit-ies, etc). There are also some technical details like dimensions and mass of sys-tems blocks of no real importance for typical applications. Other parameters like blackbody accuracy, blackbody temperature range are important when testing commercial thermal imagers for non contact temperature measurement but not crit-ical when testing surveillance thermal imagers. Further on, if the tests are to be done at laboratory conditions then wide working ambient temperature range offered by one manufacturer is not a real advantage over a system from another manufacturer capable to work only at laboratory conditions. We have a totally dif-ferent situation if the blackbody from the test system is to be used also in temperat-ure chambers for calibration applications. Therefore it is always recommended to think carefully about requirements on the test system and limit these requirements only to truly needed level. This recommendation is important as equipment charac-terized by some non typical parameters is often much more costly than typical test system.

To summarize, both cost-effective buying and effective use of systems for test-ing thermal imagers are difficult tasks. Well educated, properly trained test team is needed in both these tasks.

About Author:

Krzysztof Chrzanowski received his Ph.D., and D.Sc. both in Electronics, from Military University of Technology in Warsaw, Poland. He works currently as Pro-fessor in the mentioned above university. He is also CEO of a spin off company:

Inframet (www.inframet.com). His main scientific interests include analysis, test-ing and computer simulation of electro-optical surveillance systems (thermal im-agers, night vision devices, TV cameras, laser range finders, multi-sensor surveil-lance systems), non-contact thermometry and general metrology. He is an author or co-author of over 100 scientific papers and conference communications.

This books presents knowledge of the author on testing thermal imagers that was accumulated during over two decades of scientific work in the field of electro-op-tical technology interconnected with a series of pracelectro-op-tical projects. The author hopes that this book can become a practical guide in field of testing thermal imagers for a wide community of people interested in this fascinating technology of thermal imaging.