Choosing Between Cooled or Uncooled Technology

When it comes to thermal imaging cameras, the choice between cooled and uncooled models is pivotal. Each has its strengths, but understanding their differences and applications will help you make an informed decision.

What Makes Cooled Thermal Cameras Stand Out?

Cooled thermal cameras use an imaging sensor integrated with a cryocooler to lower the sensor’s temperature to cryogenic levels. This cooling significantly reduces thermal noise, ensuring a clear signal from the scene being observed. However, cryocoolers have moving parts with tight mechanical tolerances that wear over time, as well as helium gas that gradually escapes past seals. This results in the need for periodic cryocooler rebuilds, typically after 10,000–13,000 hours of use. These factors, along with higher costs, mean cooled cameras are often reserved for specialised applications.

The Advantages of Uncooled Thermal Cameras

Uncooled cameras are more affordable and require less maintenance, making them a practical choice for many standard applications. But when should you opt for a cooled camera instead?

When to Choose a Cooled Thermal Camera

Cooled cameras excel in applications requiring:

• • Detection of minute temperature differences

• • Superior image quality

• • High-speed capture capabilities

• • Precision temperature measurements of small targets

• • Visualisation within specific infrared wavelengths

• • Synchronisation with other measurement systems

When to Choose an Uncooled Thermal Camera

Uncooled cameras are ideal for applications requiring:

• • Cost-effective solutions for general thermal imaging needs

• • Low maintenance requirements with no cryocooler to service or replace

• • Rugged and reliable performance, suitable for long-term operation

• • Faster start-up times, as they require no cooling-down period

• • Compact and portable designs for ease of use in various environments

• • Applications in standard infrared wavelengths, where extreme sensitivity or high speed is unnecessary

Comparing Performance: Real-World Examples

High-Speed Imaging

Consider imaging a tyre rotating at 20 mph. A cooled thermal camera, with its fast capture rate, can freeze the motion of the tyre, showing precise details. In contrast, an uncooled camera struggles to keep up, leading to blurred or incomplete images.

Spatial Resolution

The spatial resolution of a thermal camera determines the level of detail it can capture. A cooled camera, paired with a 4× close-up lens, achieves a remarkable 3.5 μm spot size due to its ability to sense shorter infrared wavelengths. An uncooled camera, with a 1× close-up lens, delivers a 25 μm spot size, limiting its ability to capture fine details.

Sensitivity

Sensitivity is critical in detecting subtle temperature differences. In a simple experiment, a handprint left on a wall was imaged using both cooled and uncooled cameras. The cooled camera, with its 20 mK sensitivity, detected the handprint’s thermal signature even two minutes after contact. The uncooled camera, with 50 mK sensitivity, showed only faint remnants. This superior sensitivity allows cooled cameras to reveal even the slightest thermal anomalies.

Spectral Filtering

Cooled cameras offer unmatched flexibility with spectral filtering. For instance:

1. Imaging Through Flames: By applying a spectral filter that matches a wavelength transmissive through flames, a cooled camera can image coal particles combusting within a flame—something unachievable with uncooled models.

2. Detecting Nitrous Oxide: Using a Nitrous Oxide filter, a cooled camera visualised gas leaks in older mask designs, enabling the development of safer, more efficient systems.

Which Camera is Right for You?

The decision between cooled and uncooled thermal cameras ultimately depends on your application needs. If your work involves capturing high-speed events, detecting fine thermal details, or leveraging spectral filtering, a cooled camera is the ideal choice. For general-purpose imaging, an uncooled camera offers excellent performance at a lower cost. For tailored solutions to your thermal imaging challenges, contact Thermal Vision Direct today. Our experts are ready to guide you in finding the perfect camera for your application.