Spatial uniformity and temporal stability of pixel-to-pixel variation in mini-SiTian CMOS detector

High-precision flat-fields correction is essential for precision astronomical photometry, with pixel-to-pixel variation correction playing a key role. This study quantitatively evaluates the temporal stability and spatial uniformity of pixel-to-pixel variations in the Sony IMX455 ZWO ASI6200MM Pro CMOS detector, using flat-fields images observed by mini-SiTian. We developed a pixel-to-pixel variation correction strategy with universal applicability. Our results show that pixel-to-pixel variations are typically ∼0.365%, with temporal stability better than 0.1% over one year. A stable, time-invariant spatial non-uniformity at the level of ∼0.006% is also identified. We further investigate the effects of binning, the correlation between the responses of adjacent pixels, and provide a rough comparison with two e2v CCD detectors. This work offers a comprehensive characterization of pixel-level stability in CMOS detectors and delivers strategic insights for future survey projects focused on precision photometric performance.