Thermal sensitivity defines the smallest temperature difference that a thermal imaging camera can detect, which directly affects the clarity and sharpness of the image that an infrared camera can produce. Thermal imaging cameras have nominal sensitivity in units of millikelvin (mK). The lower the value is, the more sensitive the infrared detector will be. Thermal sensitivity, also known as noise-equivalent temperature difference (NETD), describes the smallest temperature difference observed when using a thermal imaging camera. In fact, the lower the NETD value is, the better the thermal sensor's ability to detect small temperature differences. Integrators and developers should look for manufacturers who can provide NETD performance at the industry standard 30°C, the table below can be used to evaluate thermal detector sensitivity
Some low-cost cameras from some manufacturers do this by specifying the NETD at an ambient temperature of 50°C (NETD: XXmK, @50°C) instead of the industry standard 30°C (NETD: XXmK, @30°C), so that they can hide their low sensitivity issues. If the targets you need to measure often have large temperature differences, then entry-level products with lower thermal sensitivity will suffice. However, for more subtle applications, such as detecting humidity issues, you will need a higher sensitivity thermal imaging camera.