Real-Time Spot Detection and Ordering for a Shack–Hartmann Wavefront Sensor With a Low-Cost FPGA

Mauch, Steffen; Reger, Johann

doi:10.1109/tim.2014.2310616

Cited by 29 publications

(17 citation statements)

References 23 publications

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“…The practical applicability of the method has been demonstrated in various experiments paired with extensions such as the adaptive repositioning and thresholding [9,[18][19][20].…”

Section: Resultsmentioning

confidence: 99%

“…This idea has been presented in Ref. [18] and behaves similar to the standard approach for the regular case, that is, the wavefront is not strongly disturbed. However, the advantage of this approach appears whenever a large defocus is present in the wavefront to be measured since shrinking or increasing the overall distance between two neighbored centroids is not a problem for the segmentation method.…”

Section: Fpga-based Shwfs Evaluationmentioning

confidence: 93%

“…Using a BRAM has the advantage that the consumption of logic cells is reduced as the BRAM is a dedicated peripheral offered by most FPGAs. The overall logic consumption can be kept at a minimum [18]. The assignment or segmentation of the centroids is visualized in Figures 8 and 9.…”

Section: Fpga-based Shwfs Evaluationmentioning

confidence: 99%

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Real‐Time Adaptive Optic System Using FPGAs

Mauch¹,

Reger²

2017

Field - Programmable Gate Array

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For "adaptive optics" (AO) that are used in a control loop, sensing of the wavefront is essential for achieving a good performance. One facet in this context is the delay introduced by the wavefront evaluation. This delay should be kept to a minimum. Since the problem can be split into multiple subproblems, field-programmable gate arrays (FPGAs) may beneficially be employed in view of the FPGAs' power to compute many tasks in parallel. The evaluation of, e.g., a Shack-Hartmann wavefront sensor (SHWFS) may simply be seen as the evaluation of an image. Therefore, in general, image processing methods may be split into multiple assignments such as connected component labeling (CCL). In this chapter, a new method for real-time evaluation of an SHWFS is introduced. The method is presented in combination with a rapid-control prototyping (RCP) system that is based on real-time Linux operating system.

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“…The practical applicability of the method has been demonstrated in various experiments paired with extensions such as the adaptive repositioning and thresholding [9,[18][19][20].…”

Section: Resultsmentioning

confidence: 99%

Section: Fpga-based Shwfs Evaluationmentioning

confidence: 93%

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Real‐Time Adaptive Optic System Using FPGAs

Mauch¹,

Reger²

2017

Field - Programmable Gate Array

Self Cite

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“…Methods for evaluating the spots of an SHWFS with an FPGA may now be developed specificly for increasing the setup's performance to a large extent. For this new setup, a novel approach for evaluating the wavefront with an FPGA is presented in 10,11 where a reduction of evaluation time in the SHWFS by more than half of the original delay-formally 3 ms reduced to 1.5 ms-has been achieved. Demonstrated by simulation studies, the decrease of latency to 1.5 ms of the SHWFS may yield an overall increase of bandwidth to about 350 Hz instead of the formerly achieved 100 Hz.…”

Section: Resultsmentioning

confidence: 99%

“…The delay/latency from the SHWFS is reduced extensively while even increasing the framerate. 10,11 Therefore, the main contributions of the paper are the introduction of a rapid prototyping system that shows reduced delay/latency and accelerated computation, and further allows for its evaluation with the recently developed adaptive optical test-bench.…”

Section: Introductionmentioning

confidence: 99%

FPGA-accelerated adaptive optics wavefront control

et al. 2014

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The speed of real-time adaptive optical systems is primarily restricted by the data processing hardware and computational aspects. Furthermore, the application of mirror layouts with increasing numbers of actuators reduces the bandwidth (speed) of the system and, thus, the number of applicable control algorithms. This burden turns out a key-impediment for deformable mirrors with continuous mirror surface and highly coupled actuator influence functions. In this regard, specialized hardware is necessary for high performance real-time control applications. Our approach to overcome this challenge is an adaptive optics system based on a Shack-Hartmann wavefront sensor (SHWFS) with a CameraLink interface. The data processing is based on a high performance Intel Core i7 Quadcore hard real-time Linux system. Employing a Xilinx Kintex-7 FPGA, an own developed PCie card is outlined in order to accelerate the analysis of a Shack-Hartmann Wavefront Sensor. A recently developed real-time capable spot detection algorithm evaluates the wavefront. The main features of the presented system are the reduction of latency and the acceleration of computation For example, matrix multiplications which in general are of complexity O(n3 are accelerated by using the DSP48 slices of the field-programmable gate array (FPGA) as well as a novel hardware implementation of the SHWFS algorithm. Further benefits are the Streaming SIMD Extensions (SSE) which intensively use the parallelization capability of the processor for further reducing the latency and increasing the bandwidth of the closed-loop. Due to this approach, up to 64 actuators of a deformable mirror can be handled and controlled without noticeable restriction from computational burdens

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