What is NETD in a Thermal Camera?
Engineer Manager Name: Melin
WhatsApp/ Wechat: 0086-18291418396
E-mail: melin@ireeda.com
What is NETD?
You may come across the expression of “NETD” when you look at the technical details of a thermal camera. The stands for “Noise Equivalent Temperature Difference”. It can be represented with numbers and the lower the number, the more sensitive the camera. It is also defined as the minimum detectable temperature difference between an object and its background. In other words, NETD is the temperature difference that provides a signal-to-noise ratio of 1. So, if the NETD of a camera is 100mk (or 0.1°C) it can theoretically discern a 25.1°C drone against a 25.0°C sky.NETD is typically being expressed in milli-Kelvin (mK).
In practice, this means that when the temperature difference of an object drops down low enough, the heat signature it is radiating may merge with noise to such an extent that the thermal imager can fail to distinguish the object’s signal from noise. When this happens the object in the scene merges with the background or other objects in the scene and becomes practically indiscernible. Therefore, the lower the NETD value the better the sensor can register small temperature differences. The below scale can be used to determine the quality of a thermal detector:
<25 mK (Excellent)
<40 mK (Good)---Our factory has DA--675B 、6100B、6100Cmultifunctional handheld thermal binocularthat can meet this condition.
<50 mK (Acceptable)---Our factory has DA-350B、650B handheld thermal imaging binoculars that can meet this condition.
<60 mK (Satisfactory)
How does NETD affect the measurement?
The images below show the same scene recorded by two different cameras. One camera has an NETD of 60 mK and the second has value of 80 mK. The areas in the image with very low temperature show significantly more noise in the image taken with the 80 mK camera. 20 mK difference doesn’t seem like much, but it has a potentially huge impact on the image quality and measurement accuracy.
What does a lower NETD mean?
- Easier to clearly see the objects in the IR-image
- Higher efficiency with a better image
- Easier to catch the focus
- More professional-looking reports wіth better images
- Last but not least, good images are easier to understand
Engineer Manager Name: Melin
WhatsApp/ Wechat: 0086-18291418396
E-mail: melin@ireeda.com
