Real-time en-face Gabor optical coherence tomographic angiography on human skin using CUDA GPU

OCTSharp: an open-source and real-time OCT imaging software based on C

Optical coherence tomography (OCT) demands massive data processing and real-time displaying during high-speed imaging. Current OCT imaging software is predominantly based on C++, aiming to maximize performance through low-level hardware management. However, the steep learning curve of C++ hinders agile prototyping, particularly for research purposes. Moreover, manual memory management poses challenges for novice developers and may lead to potential security issues. To address these limitations, OCTSharp is developed as an open-source OCT software based on the memory-safe language C#. Within the managed C# environment, OCTSharp offers synchronized hardware control, minimal memory management, and GPU-based parallel processing. The software has been thoroughly tested and proven capable of supporting real-time image acquisition, processing, and visualization with spectral-domain OCT systems equipped with the latest advanced hardware. With these enhancements, OCTSharp is positioned to serve as an open-source platform tailored for various applications.

Dual-wavelength off-axis digital holography in ImageJ: toward real-time phase retrieval using CUDA streams

An ImageJ plug-in is developed to realize automatic real-time phase reconstruction for dual-wavelength digital holography (DH). This plug-in assembles the algorithms, including automatic phase reconstruction based on the division algorithm and post-processing. These algorithms are implemented and analyzed using a CPU and GPU, respectively. To hide the CPU-to-GPU data transfer latency, an optimization scheme using Compute Unified Device Architecture (CUDA) streams is proposed in ImageJ. Experimental results show that the proposed plug-in can perform faster reconstruction for dual-wavelength DH, resulting in frame rates up to 48 fps even for one-megapixel digital holograms on a normal PC. In other words, the proposed plug-in can realize real-time phase reconstruction for dual-wavelength digital holographic videos.

GPU-accelerated image registration algorithm in ophthalmic optical coherence tomography

Limited to the power of the light source in ophthalmic optical coherence tomography (OCT), the signal-to-noise ratio (SNR) of the reconstructed images is usually lower than OCT used in other fields. As a result, improvement of the SNR is required. The traditional method is averaging several images at the same lateral position. However, the image registration average costs too much time, which limits its real-time imaging application. In response to this problem, graphics processing unit (GPU)-side kernel functions are applied to accelerate the reconstruction of the OCT signals in this paper. The SNR of the images reconstructed from different numbers of A-scans and B-scans were compared. The results demonstrated that: 1) There is no need to realize the axial registration with every A-scan. The number of the A-scans used to realize axial registration is suitable to set as ∼25, when the A-line speed was set as ∼12.5kHz. 2) On the basis of ensuring the quality of the reconstructed images, the GPU can achieve 43× speedup compared with CPU.

Dynamic inverse SNR-decorrelation OCT angiography with GPU acceleration

Dynamic OCT angiography (OCTA) is an attractive approach for monitoring stimulus-evoked hemodynamics; however, a 4D (3D space and time) dataset requires a long acquisition time and has a large data size, thereby posing a great challenge to data processing. This study proposed a GPU-based real-time data processing pipeline for dynamic inverse SNR-decorrelation OCTA (ID-OCTA), offering a measured line-process rate of 133 kHz for displaying OCT and OCTA cross-sections in real time. Real-time processing enabled automatic optimization of angiogram quality, which improved the vessel SNR, contrast-to-noise ratio, and connectivity by 14.37, 14.08, and 9.76%, respectively. Furthermore, motion-contrast 4D angiographic imaging of stimulus-evoked hemodynamics was achieved within a single trail in the mouse retina. Consequently, a flicker light stimulus evoked an apparent dilation of the retinal arterioles and venules and an elevation of the decorrelation value in the retinal plexuses. Therefore, GPU ID-OCTA enables real-time and high-quality angiographic imaging and is particularly suitable for hemodynamic studies.