Research of fiber position measurement by multi CCD cameras

摘要

Parallel controlled fiber positioner as an efficiency observation system, has been used in LAMOST for four years, and will be proposed in ngCFHT and rebuilt telescope Mayall. The fiber positioner research group in USTC have designed a new generation prototype by a close-packed module robotic positioner mechanisms. The prototype includes about 150 groups fiber positioning module plugged in 1 meter diameter honeycombed focal plane. Each module has 37 12mm diameter fiber positioners. Furthermore the new system promotes the accuracy from 40 um in LAMOST to 10um in MSDESI. That's a new challenge for measurement. Close-loop control system are to be used in new system. The CCD camera captures the photo of fiber tip position covered the focal plane, calculates the precise position information and feeds back to control system. After the positioner rotated several loops, the accuracy of all positioners will be confined to less than 10um. We report our component development and performance measurement program of new measuring system by using multi CCD cameras. With the stereo vision and image processing method, we precisely measure the 3-demension position of fiber tip carried by fiber positioner. Finally we present baseline parameters for the fiber positioner measurement as a reference of next generation survey telescope design.