What is Non-Uniformity Correction (NUC) of infrared thermal camera?

It is to adjust for small detector drift that occurs when the scene and environment change.

What is a Non-Uniformity Correction (NUC)?

Infrared thermal cameras have super night vision capabilities, so they are widely used as target detection, search and tracking. 

Traditional thermal imaging cameras will cause column noise, severe image degradation due to temperature changes, thereby affecting the observation effect. Therefore, it is necessary to perform Non-uniformity correction through the shutter. 

Due to the limitations of device materials and manufacturing processes, there are some differences between the detection units on the same focal plane array, resulting in obvious non-uniformity in the infrared image. 

In addition, the non-uniformity of the infrared image is greatly affected by the changes of the image scene. In the uncooled infrared imaging system, it is also affected by the temperature changes of the infrared focal plane array, which seriously reduces the imaging quality of the infrared system. 

Non-uniformity correction (NUC) is to adjust for small detector drift that occurs when the scene and environment change. Under normal circumstances, the thermal camera’ s own heat will interfere with its temperature readings. 

In order to improve accuracy, the thermal camera will measure the infrared radiation of its own optics, and then adjust the image based on these readings. NUC adjusts the gain and offset for each pixel to generate higher quality and more accurate images.

When will the thermal imager execute NUC?

At the initial startup, the thermal camera will frequently execute NUC. 

As the thermal camera heats up, reaches a stable operating temperature, NUC will become less frequent. Although you can get the thermal image in about 20 seconds after power on the camera, most thermal imagers require much longer time of warm-up time, in a stable environment, with the best temperature measurement accuracy.
The thermal camera will automatically perform a NUC, but you can also use the NUC function manually before measuring temperature or taking key images. This will help ensure the best accuracy.

Why there is clicking noise during thermal camera working?

During a NUC, the camera shutter comes down between optic and detector, making a clicking sound and freezing the image stream momentarily. The shutter acts as a flat reference source for the detector to calibrate itself to and thermally stabilize.
This happens regularly in uncooled infrared cameras, but don’ t need to worry about it.

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