Revisiting the SHINE high-contrast imaging exoplanet survey using the Regime Switching Model

High-contrast imaging is a key technique for detecting and characterising young giant exoplanets, probing parameter space largely inaccessible to other methods. Despite advances in adaptive optics, coronagraphy, and post-processing, ground-based observations remain limited by residual stellar noise, particularly at small angular separations. This thesis investigates the application of the Regime Switching Model (RSM) to the F150 sample of the SHINE survey to improve detection sensitivity in this regime. RSM was applied to more than 200 observations to derive detection maps and limits, while the influence of observing conditions on detection thresholds was investigated using clustering and noise modeling.  RSM improves contrast by approximately a factor of two overall and up to five at small angular separations compared with standard PCA processing. A total of 89 signals were recovered, including four background-star candidates and no new planetary candidates. Distinct observational regimes show detection-threshold variations of up to an order of magnitude, highlighting the importance of accounting for observing conditions. Overall, this work demonstrates that RSM is an effective detection framework for improving the sensitivity of high-contrast imaging observations, particularly at small angular separations. However, robust threshold calibration and PSF subtraction remain important challenges for its reliable application to archival and future imaging surveys.