Borkovkina Svetlana, Camino Acner, Janpongsri Worawee, Sarunic Marinko V, Jian Yifan
Department of Engineering Science, Simon Fraser University, Burnaby, Canada.
Casey Eye Institute, Oregon Health & Science University, Portland, OR 27239, USA.
Biomed Opt Express. 2020 Jun 24;11(7):3968-3984. doi: 10.1364/BOE.395279. eCollection 2020 Jul 1.
Segmentation of retinal layers in optical coherence tomography (OCT) is an essential step in OCT image analysis for screening, diagnosis, and assessment of retinal disease progression. Real-time segmentation together with high-speed OCT volume acquisition allows rendering of OCT of arbitrary retinal layers, which can be used to increase the yield rate of high-quality scans, provide real-time feedback during image-guided surgeries, and compensate aberrations in adaptive optics (AO) OCT without using wavefront sensors. We demonstrate here unprecedented real-time OCT segmentation of eight retinal layer boundaries achieved by 3 levels of optimization: 1) a modified, low complexity, neural network structure, 2) an innovative scheme of neural network compression with TensorRT, and 3) specialized GPU hardware to accelerate computation. Inferencing with the compressed network U-NetRT took 3.5 ms, improving by 21 times the speed of conventional U-Net inference without reducing the accuracy. The latency of the entire pipeline from data acquisition to inferencing was only 41 ms, enabled by parallelized batch processing. The system and method allow real-time updating of OCT and OCTA visualizations of arbitrary retinal layers and plexuses in continuous mode scanning. To the best our knowledge, our work is the first demonstration of an ophthalmic imager with embedded artificial intelligence (AI) providing real-time feedback.
光学相干断层扫描(OCT)中视网膜层的分割是OCT图像分析中的一个重要步骤,用于视网膜疾病的筛查、诊断和病情进展评估。实时分割与高速OCT容积采集相结合,能够生成任意视网膜层的OCT图像,可用于提高高质量扫描的产出率、在图像引导手术期间提供实时反馈,以及在不使用波前传感器的情况下补偿自适应光学(AO)OCT中的像差。我们在此展示了通过三个层次的优化实现的前所未有的八个视网膜层边界的实时OCT分割:1)一种经过改进的、低复杂度的神经网络结构;2)一种采用TensorRT的创新神经网络压缩方案;3)用于加速计算的专用GPU硬件。使用压缩网络U-NetRT进行推理耗时3.5毫秒,在不降低准确率的情况下,将传统U-Net推理速度提高了21倍。通过并行批处理,从数据采集到推理的整个流程延迟仅为41毫秒。该系统和方法允许在连续模式扫描中实时更新任意视网膜层和神经纤维层的OCT和OCTA可视化图像。据我们所知,我们的工作首次展示了一种具有嵌入式人工智能(AI)并能提供实时反馈的眼科成像仪。