WORKSHOP PAPER
The State-of-the-Art of Smartphone Imagers
Abstract
The smartphone imaging ecosystem is well into the “imaging plus” era. Advanced chip stacking techniques have enabled new functionality, including multi-frame noise reduction, slow-motion video, and other advanced image signal processing features. Pixel-level interconnect has been successfully demonstrated and is coming soon to mass-produced CMOS image sensors (CIS). Active pixel arrays, including the latest 0.8 µm pixel generation, are now commonly augmented with specialized phase detection autofocus (PDAF) pixels. The rise of 2x1 on-chip lens (OCL) structures has been noted in sub-micron pixels as an enabler for lossless PDAF. Flagship smartphones now employ multiple camera systems, with each camera in the ecosystem customized per use case. The multi-cam approach is driving improved image quality, and the trend to include companion time-of-flight (ToF) cameras is enabling new feature sets to assist these advanced imaging systems.Keywords
Smartphone Imaging, CMOS Image Sensors, Chip Stacking Techniques,References
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