**5. Conclusion**

However, the new approach has no problem and correctly assigns the spots to the lenses and

thus correctly measures the wavefront (**Figure 20**).

192 Field - Programmable Gate Array

The use of FPGAs in the context of AO has proven to be very beneficial with respect to the achievable performance, especially in closed‐loop operation. One positive aspect is the direct evaluation of the SHWFS on the FPGA which allows to minimize the delay and to increase the throughput. For the evaluation of the SHWFS, new approaches have been presented which surpass or considerably extend existing methods. However, they have not reached possible limits so far, particularly, in terms of the achievable dynamic range of the SHWFS.

The practical applicability of the method has been demonstrated in various experiments paired with extensions such as the adaptive repositioning and thresholding [9, 18–20].

For designing AO setups and optimizing its performance, interdisciplinary groups are indispensable. In this context, the control engineers may synthesize their simulation models directly in code for closed‐loop operation. Such an RCP system may also be a commercial solution such as dSpace. Yet, the presented RTAI‐based hard real‐time Linux system has the important benefit to be of far lower initial cost with respect to hardware while granting higher flexibility and ease of customization.
