论文信息 - The low-order wavefront control system for the PICTURE-C mission: deformable mirror anti-aliasing through temporal dithering

The low-order wavefront control system for the PICTURE-C mission: deformable mirror anti-aliasing through temporal dithering

The Planetary Imaging Concept Testbed Using a Recoverable Experiment - Coronagraph (PICTURE-C) is a direct imaging experiment designed to observe exozodiacal dust and debris disks that orbit nearby stars from a high-altitude balloon platform. The experiment consists of a vector vortex coronagraph and a multi stage adaptive optics system with multiple wavefront sensors and two deformable mirrors. This paper details the hardware and software implementation of one of the DM interfaces used in the PICTURE-C low-order wavefront control system. We discuss the algorithm used to drive a commercial o_-the-shelf DM with an actuation resolution of 14-bits to meet the PICTURE-C requirement of 16-bits. The algorithm utilizes fast temporal dithering in the form of pulse density modulation to reduce the quantization error of the DM actuation. The described DM control mechanism can operate at a framerate of ~500 Hz with an equivalent actuation resolution of 16-bits with minimal computational load on the deployed processor.

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