MEMS-based handheld scanning probe with pre-shaped input signals for distortion-free images in Gabor-domain optical coherence microscopy

Abstract

High-speed scanning in optical coherence tomography (OCT) often comes with either compromises in image quality, the requirement for post-processing of the acquired images, or both. We report on distortion-free OCT volumetric imaging with a dual-axis micro-electro-mechanical system (MEMS)-based handheld imaging probe. In the context of an imaging probe with optics located between the 2D MEMS and the sample, we report in this paper on how pre-shaped open-loop input signals with tailored non-linear parts were implemented in a custom control board and, unlike the sinusoidal signals typically used for MEMS, achieved real-time distortion-free imaging without post-processing. The MEMS mirror was integrated into a compact, lightweight handheld probe. The MEMS scanner achieved a 12-fold reduction in volume and 17-fold reduction in weight over a previous dual-mirror galvanometer-based scanner. Distortion-free imaging with no post-processing with a Gabor-domain optical coherence microscope (GD-OCM) with 2 μm axial and lateral resolutions over a field of view of 1 × 1 mm² is demonstrated experimentally through volumetric images of a regular microscopic structure, an excised human cornea, and in vivo human skin.

Temperature variations in sintering ovens for metal ceramic dental prostheses: Non-destructive assessment using OCT

“…Our ongoing work has fully completed these analysis and rules-of-thumb have been extracted for these assessments [31,32]. Future work in our groups includes such analysis in the oral cavity, on prostheses already set in place, with fast-imaging OCT systems equipped with handheld scanning probes [25,26,29,33].…”

“…The penetration depth of OCT is limited to about 1.5 mm (especially in hard tissue), while its typical axial resolution is around 10 m (although resolutions of 2 m are also available [29]). The question is if these characteristics are suffcient to assess the temperature variations in dental ovens, by studying ceramics granulation inside the samples.…”

Image-Guided Laparoscopic Surgical Tool (IGLaST) Based on the Optical Frequency Domain Imaging (OFDI) to Prevent Bleeding

“…Typically, the penetration depth is about 1–3 mm in tissue, and the depth resolution is about 10–15 µm [10]. OFDI has also been applied to studying the structural features of skin, gynecological tissues, and gastrointestinal tract [11,12,13,14]. Most previous studies on medical devices using OFDI focused on discriminating between normal and diseased or cancerous tissues based on microstructural features.…”

Motorized Microforceps With Active Motion Guidance Based on Common-Path SSOCT for Epiretinal Membranectomy

“…In order to develop a real-time OCT intraoperative guidance system, we employed a parallel programming technique that uses a graphic processing unit (GPU) for fast computational speed and incorporated it into the microsurgical tool system [17]. This distal sensing application is distinguished from the typical OCT “B-scan/C-scan” imaging application [18] in that our distal sensing system measures a distance value by acquiring A-scan data, with its attendant complexity [19-25]. The OCT data in our application is subsequently transformed to distance information rather than morphological information, and is directly utilized for motion control in real-time.…”