An investigation into the high contrast performance of the IMX492 and IMX571 imaging sensors

Le résumé fourni par la source

High-contrast coronagraphic imaging in reflected light requires suppression of stellar light by factors exceeding 1×10−9, placing stringent demands on imaging sensor performance. This study investigates the behavior of two industrial-grade Sony CMOS sensors, the IMX492 (Pregius) and IMX571 (Starvis), used on the Space Coronagraph Optical Bench (SCoOB) at Steward Observatory. While the IMX492 consistently achieved contrast ratios below 5×10−9, the IMX571 exhibited contrast ratios limited to 4×10−8. We present a comparative analysis of apparent charge diffusion behavior using a combination of DN equivalency modeling, quad cell centroiding, and saturation profiling. The IMX492 demonstrates robust charge containment even under supersaturation with minimal lateral diffusion. In contrast, the IMX571 shows early charge spread, diagonal blooming, regional saturation effects, and asymmetric diffusion, suggesting weaker anti-blooming architecture. Experimental results include knife-edge tests, HeNe laser exposures, and pixel-level saturation analysis. These findings highlight the critical role of sensor architecture in extreme contrast applications. While Starvis sensors prioritize sensitivity, their bloom control limitations may preclude their use in high-contrast astronomical instrumentation.

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