Noise reduction for temperature-sensitive paint measurement contaminated by strong background radiation in a high enthalpy hypersonic tunnel

The strong background radiation in high enthalpy hypersonic shock tunnels has posed severe challenges for measurement using luminescent coatings. We proposed a solution reducing from time-resolved temperature-sensitive paint (TSP) flow with Ma = 6.5 and T0 3525 K. TSP was applied on an inlet ramp model, the images were taken by high-speed camera at 2 kHz under modulated excitation. led to low signal-to-noise ratio significant errors first half of 130-ms test duration. Accordingly, three noise reduction methods developed evaluated based temporal reconstruction, spatial reconstruction robust principal component analysis (RPCA), respectively. RPCA method showed best performance that successfully recovered high-quality data majority duration (t ≥ 40 ms).