Cooled Vs. Uncooled Thermal Cameras for Long-Range Surveillance

 

When you need continuous surveillance of city borders or property of a large facility in any environment or condition, a long-range thermal camera system is perfect for the job. There are two types of thermal camera systems available for these applications, cooled and uncooled. We would like to break down the technical differences between the two, and explain the costs and benefits associated with each to help you decided on the right one.

The video above compares the level of detail between cooled and uncooled footage in 640×480 resolution with objects that are far and near.

Cooled Thermal Camera

A cooled thermal camera’s imaging sensor is integrated with a cryocooler. The cryocooler lowers the sensor temperature to cryogenic temperatures. This drop in sensor temperature is necessary to lessen thermally induced noise to a level below that of the signal from the scene being imaged. Cooled thermal cameras are more sensitive to small differences in scene temperature than are uncooled cameras, making cooled cameras more suitable for extremely long-range imaging in low-contrast scenes.

Uncooled Thermal Camera

Uncooled infrared cameras do not use cryogenic cooling. A common detector design is based on the microbolometer, a tiny vanadium oxide resistor with a large temperature coefficient on a silicon element with large surface area, low heat capacity and good thermal isolation.

Cooled or uncooled? What to choose?

With all of the advantages of uncooled cameras in mind, it begs the question: why use cooled cameras? The answer: when standoff ranges reach 5km or greater, cooled thermal cameras systems quickly become more cost-effective. Note the emphasis on the word \”systems\” – the camera is the only component of an imaging \”system\”. One of the biggest cost drivers of a long-range uncooled camera system is the lens. As effective range requirements increase, the lenses for uncooled camera systems become so bulky and expensive that it can often be cheaper to specify a cooled camera with an equivalent focal length lens.

Conclusion

Long-range thermal surveillance applications require long focal length lenses. The cost of lenses increases rapidly with focal length for uncooled camera systems and rather slowly for cooled systems. As a result, even though the cost of a cooled camera core is much higher than an uncooled core, the system cost (core plus lens) for uncooled surpasses cooled system cost at a focal length on the order of 350mm. Useful imaging of man-sized targets at long ranges requires focal lengths that exceed 350mm. Therefore, long-range imaging of man-sized targets is less expensive with a cooled camera system, at least when only considering system acquisition cost.
It is important to take the 8,000-10,000 hour lifetime of cryocoolers into account when trying to arrive at the best solution. If the cryocooler needs a servicing every 2 years, and the cost is 10% of the total system, then the 4-year cost of the cooled system is really 1.2X the initial system cost.

Having more than 20 years of experience with thermal imaging cameras, and supplying both cooled and uncooled systems, ThermalVideo.com can always provide you with the necessary information to make a well-informed decision for your particular application.

Data from FLIR Systems Technical Notes

 

 

Are Public Regulations Needed For Commercial UAV Usage?

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Behind every new and successful technology advancement, such as unmanned aerial vehicles (UAV), there\’s a history of countless flaws and accidents that have led up to its current design. I mean let\’s face it, like us, technologies are prone to accidents as much as the intelligence behind it. Over the century, the automobile industry has implemented many rules and regulations for operating motor vehicles for the general safety of the public. And as we progress towards a nation with company-operated drones occupying our airspace by 2015, we need to prepare ourselves for the same.

Like a driver behind the wheel, drones are as prone to accidents as the users behind the controls are. There have been physical accidents reported with UAVs, such as a camera-equipped quadcoptor crashing into a wedding shoot or a pedestrian almost colliding with a drone as it crash landed near Grand Central Station. These incidents bring up the question, who is to blame? The machine or the operator?

\”In the late 1920s, aircrafts were still failing out of the sky left and right,\” Missy Cummings, who studies drones and autonomous systems at MIT, said at a panel discussion at the Drones and Aerial Robotics Conference (DARC) in New York on Saturday. Today, drone technology is at the same place. If we can easily fix and repair the technology to perform properly and more efficiently then we need to implement the same with the operators. – Subbaraman

Operators of small military drones are trained and certified before they can use them. This training system should be carried out with domestic operators as well. Like a driver license, operators interested in using the technology should apply for a pre-use certification and take a course on flying and safety rules before flying on their own. The more educated an operator is with his/her machine, the less likely accidents will occur under their control.

Do you thinks operators should apply for a \”drone driving license\” before operating a UAV?
What do you think about drunk drone driving?

Please share your thoughts with us!

Work Cited

\”Drone driver licenses? How to make flying robots safe for American skies\” – Nidhi Subbaraman, NBC News