FPGA design & implementation of a very-low-latency video-see-through (VLLV) head-mount display (HMD) system for mixed reality (MR) applications

Author(s):  
Tao Ai
2021 ◽  
Vol 7 (12) ◽  
pp. 274
Author(s):  
Dominique Franson ◽  
Andrew Dupuis ◽  
Vikas Gulani ◽  
Mark Griswold ◽  
Nicole Seiberlich

Image-guided cardiovascular interventions are rapidly evolving procedures that necessitate imaging systems capable of rapid data acquisition and low-latency image reconstruction and visualization. Compared to alternative modalities, Magnetic Resonance Imaging (MRI) is attractive for guidance in complex interventional settings thanks to excellent soft tissue contrast and large fields-of-view without exposure to ionizing radiation. However, most clinically deployed MRI sequences and visualization pipelines exhibit poor latency characteristics, and spatial integration of complex anatomy and device orientation can be challenging on conventional 2D displays. This work demonstrates a proof-of-concept system linking real-time cardiac MR image acquisition, online low-latency reconstruction, and a stereoscopic display to support further development in real-time MR-guided intervention. Data are acquired using an undersampled, radial trajectory and reconstructed via parallelized through-time radial generalized autocalibrating partially parallel acquisition (GRAPPA) implemented on graphics processing units. Images are rendered for display in a stereoscopic mixed-reality head-mounted display. The system is successfully tested by imaging standard cardiac views in healthy volunteers. Datasets comprised of one slice (46 ms), two slices (92 ms), and three slices (138 ms) are collected, with the acquisition time of each listed in parentheses. Images are displayed with latencies of 42 ms/frame or less for all three conditions. Volumetric data are acquired at one volume per heartbeat with acquisition times of 467 ms and 588 ms when 8 and 12 partitions are acquired, respectively. Volumes are displayed with a latency of 286 ms or less. The faster-than-acquisition latencies for both planar and volumetric display enable real-time 3D visualization of the heart.


2021 ◽  
Vol 17 (2) ◽  
pp. 1-23
Author(s):  
Saman Biookaghazadeh ◽  
Pravin Kumar Ravi ◽  
Ming Zhao

High-throughput and low-latency Convolutional Neural Network (CNN) inference is increasingly important for many cloud- and edge-computing applications. FPGA-based acceleration of CNN inference has demonstrated various benefits compared to other high-performance devices such as GPGPUs. Current FPGA CNN-acceleration solutions are based on a single FPGA design, which are limited by the available resources on an FPGA. In addition, they can only accelerate conventional 2D neural networks. To address these limitations, we present a generic multi-FPGA solution, written in OpenCL, which can accelerate more complex CNNs (e.g., C3D CNN) and achieve a near linear speedup with respect to the available single-FPGA solutions. The design is built upon the Intel Deep Learning Accelerator architecture, with three extensions. First, it includes updates for better area efficiency (up to 25%) and higher performance (up to 24%). Second, it supports 3D convolutions for more challenging applications such as video learning. Third, it supports multi-FPGA communication for higher inference throughput. The results show that utilizing multiple FPGAs can linearly increase the overall bandwidth while maintaining the same end-to-end latency. In addition, the design can outperform other FPGA 2D accelerators by up to 8.4 times and 3D accelerators by up to 1.7 times.


Digital ◽  
2021 ◽  
Vol 1 (1) ◽  
pp. 34-53
Author(s):  
Mattia Tambaro ◽  
Marta Bisio ◽  
Marta Maschietto ◽  
Alessandro Leparulo ◽  
Stefano Vassanelli

Numerous experiments require low latencies in the detection and processing of the neural brain activity to be feasible, in the order of a few milliseconds from action to reaction. In this paper, a design for sub-millisecond detection and communication of the spiking activity detected by an array of 32 intracortical microelectrodes is presented, exploiting the real-time processing provided by Field Programmable Gate Array (FPGA). The design is embedded in the commercially available RHS stimulation/recording controller from Intan Technologies, that allows recording intracortical signals and performing IntraCortical MicroStimulation (ICMS). The Spike Detector (SD) is based on the Smoothed Nonlinear Energy Operator (SNEO) and includes a novel approach to estimate an RMS-based firing-rate-independent threshold, that can be tuned to fine detect both the single Action Potential (AP) and Multi Unit Activity (MUA). A low-latency SD together with the ICMS capability, creates a powerful tool for Brain-Computer-Interface (BCI) closed-loop experiments relying on the neuronal activity-dependent stimulation. The design also includes: A third order Butterworth high-pass IIR filter and a Savitzky-Golay polynomial fitting; a privileged fast USB connection to stream the detected spikes to a host computer and a sub-milliseconds latency Universal Asynchronous Receiver-Transmitter (UART) protocol communication to send detections and receive ICMS triggers. The source code and the instruction of the project can be found on GitHub.


Author(s):  
Jacqueline A. Towson ◽  
Matthew S. Taylor ◽  
Diana L. Abarca ◽  
Claire Donehower Paul ◽  
Faith Ezekiel-Wilder

Purpose Communication between allied health professionals, teachers, and family members is a critical skill when addressing and providing for the individual needs of patients. Graduate students in speech-language pathology programs often have limited opportunities to practice these skills prior to or during externship placements. The purpose of this study was to research a mixed reality simulator as a viable option for speech-language pathology graduate students to practice interprofessional communication (IPC) skills delivering diagnostic information to different stakeholders compared to traditional role-play scenarios. Method Eighty graduate students ( N = 80) completing their third semester in one speech-language pathology program were randomly assigned to one of four conditions: mixed-reality simulation with and without coaching or role play with and without coaching. Data were collected on students' self-efficacy, IPC skills pre- and postintervention, and perceptions of the intervention. Results The students in the two coaching groups scored significantly higher than the students in the noncoaching groups on observed IPC skills. There were no significant differences in students' self-efficacy. Students' responses on social validity measures showed both interventions, including coaching, were acceptable and feasible. Conclusions Findings indicated that coaching paired with either mixed-reality simulation or role play are viable methods to target improvement of IPC skills for graduate students in speech-language pathology. These findings are particularly relevant given the recent approval for students to obtain clinical hours in simulated environments.


2020 ◽  
Vol 140 (12) ◽  
pp. 1297-1306
Author(s):  
Shu Takemoto ◽  
Kazuya Shibagaki ◽  
Yusuke Nozaki ◽  
Masaya Yoshikawa

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