Non-Uniformity Compensation (a.k.a. Correction, or NUC) is not the same as automatic [gain] correction (AGC). NUC is a calibration process used to normalize the pixel-to-pixel output in thermal cameras. This is necessary because the pixels in thermal cameras do not respond identically with respect to neighboring pixels. In addition, thermal pixel response can vary as a function of ambient temperature. These are a couple of the fundamental differences between thermal cameras and visible light (CCD) cameras.
FLIR factory-calibrates every Boson thermal camera to calculate offset and gain terms for each pixel over a temperature range of -40 °C to +80 °C. These terms are stored in non-volatile camera memory and applied to the digital output upon camera operation (unless deliberately disabled by the camera operator).
From the Boson datasheet, ¶ 6.5, p. 33: AGC converts 16-bit digital video from the camera into 8-bit video so that it can be displayed on a monitor. AGC parameters (¶ 6.5.1 to 6.5.9, pp. 33-39) provide the means to adjust the analog video image to optimize scene contrast based upon the ambient conditions.