Characterizing plant material is crucial in terms of early disease detection, pest control, physiological assessments, and growth monitoring, which are essential parameters to increase production in agriculture and prevent unnecessary economic losses. The conventional methods employed to assess the aforementioned parameters have several limitations, such as invasive inspection, complexity, high time consumption, and costly features. In recent years, optical coherence tomography (OCT), which is an ultra-high resolution, non-invasive, and real-time unique image-based approach has been widely utilized as a significant and potential tool for assessing plant materials in numerous aspects. The obtained OCT cross-sections and volumetrics, as well as the amplitude signals of plant materials, have the capability to reveal vital information in both axial and lateral directions owing to the high resolution of the imaging system. This review discusses recent technological trends and advanced applications of OCT, which have been potentially adapted for numerous agricultural applications, such as non-invasive disease screening, optical signals-based growth speed detection, the structural analysis of plant materials, and microbiological discoveries. Therefore, this review offers a comprehensive exploration of recent advanced OCT technological approaches for agricultural applications, which provides insights into their potential to incorporate OCT technology into numerous industries.

Dental crowns are used to restore decayed or chipped teeth, where their surfaces play a key role in this restoration process, as they affect the fitting and stable bonding of the prostheses. The surface texture of crowns can interfere with this restoration process, therefore the measurement of their inner surface roughness is very important but difficult to achieve using conventional imaging methods. In this study, the inner surfaces of dental crowns were three-dimensionally (3D) visualized using swept-source optical coherence tomography (SS-OCT) system. Nine crowns were fabricated with a commercial 3D printer using three different hatching methods (one-way, cross, and 30° angle counter-clockwise) and three different build direction angles (0°, 45°, and 90°). In addition, an image processing algorithm was developed, which uses morphological filtering, boundary detection, and a high-pass frequency filtering technique, to quantitatively evaluate the inner surface roughness of the dental crowns cross-sections with the depth-of-focus set to match two different regions. The averaged smoothness of fabricated crown was effectively produced using the cross-hatching and the build direction angle of 90° by the respective process. Thus, the results confirm the potential use of this methodology to determine the best parameters to use in 3D fabrication for improving the effectiveness and stability of dental prostheses.

Non‐contact, high‐resolution imaging is critical in modern industrial environments, where complex and multilayered structures demand precise inspection without disrupting production. Optical coherence tomography (OCT), a non‐destructive, depth‐resolved imaging modality, has emerged as a transformative tool for real‐time visualization of internal features in advanced manufacturing processes. This review begins with the principles of OCT and provides a comprehensive analysis of its applications across key manufacturing sectors, including display inspection, thin‐film monitoring, microelectronics, printed circuit board (PCB) analysis, laser‐based manufacturing, and coating evaluation. For each domain, representative methods are examined for their effectiveness in detecting subsurface defects, measuring internal geometries, and supporting quality control. The role of OCT in industry is highlighted through comparisons with conventional inspection techniques. In addition, the review discusses current challenges across resolution, optical penetration and contrast, signal quality, system integration, hardware cost, throughput, and artificial intelligence (AI) and data infrastructure. It also highlights emerging advances in adaptive optics, multimodal and AI‐enhanced imaging, compact and portable OCT platforms, and next‐generation computational and data‐processing architectures for real‐time industrial deployment. By combining technical evaluation, comparative analysis, and future‐oriented perspectives, this review positions OCT as a core technology and foundational tool for next‐generation quality assurance in smart manufacturing and Industry 4.0 environments.

Whole-directional scanning methodology is required to observe distinctive features of an entire physical structure with a three dimensional (3D) visualization. However, the implementation of whole-directional scanning is challenging for conventional optical coherence tomography (OCT), which scans a limited portion of the sample by utilizing unidirectional and bidirectional scanning methods. Therefore, in this paper an integrated quad-scanner (QS) strategy-based OCT method was implemented to obtain the whole-directional volumetry of a sample by employing four scanning arms installed around the sample. The simultaneous and sequential image acquisition capabilities are the conceptual key points of the proposed QS-OCT method, and were implemented using four precisely aligned scanning arms and applied in a complementary way according to the experimental criteria. To assess the feasibility of obtaining whole-directional morphological structures, a roll of Scotch tape, an ex vivo mouse heart, and kidney specimens were imaged and independently obtained tissue images at different directions were delicately merged to compose the 3D volume data set. The results revealed the potential merits of QS-OCT-based whole-directional imaging, which can be a favorable inspection method for various discoveries that require the dynamic coordinates of the whole physical structure.

Optical coherence tomography (OCT) is a non-invasive and label-free optical imaging system offering real-time visualization of morphological structures. The high costs associated with most existing commercial OCT systems have restricted their widespread availability, particularly in low-resource environments. Therefore, miniaturizing OCT devices holds the potential not only to reduce size but also to lower costs, opening up new markets for this technology. In this study, we developed single board computer-based compact and portable OCT system (SBC-OCT), which was fabricated by 3D printer. The total size of the developed SBC-OCT system is 230 × 230 × 330 mm ³ . To counter the thermal-induced alignment distortion of 3D printed spectrometer during system operation, we developed an automatic signal compensation method applied temperature-insensitive spectrometer using an area-scan camera with no hardware modifications, no additional components, and minimal computational load. By comparing with conventional line-scan camera-based OCT during 90 min monitoring, the temperature variance robustness of developed SBC-OCT effectively verified and successfully restored distorted images to their original quality. In addition, the applicability of our developed SBC-OCT system was demonstrated through cornea, retina, and fingerprint anti-spoofing imaging. The reduction in size, weight, and cost of SBC-OCT makes it highly relevant across medical, industrial, and security applications, demonstrating its potential for wide-ranging usage.

Nail beautification is a widely applied gender independent practice. Excessive nail beautifications and nail-arts have a direct impact on the nail structure and can cause nail disorders. Therefore, the assessment of post-progressive nail-art effects on the nail is essential to maintain optimal nail health and to avoid any undesirable disorders. In this study, in vivo nails were examined in control stage, with a nail-art stage, and after removing the nail-art stage using a 1310 nm spectral-domain optical coherence tomography (SD-OCT) system. The acquired cross-sectional OCT images were analyzed by a laboratory customized signal processing algorithm to obtain scattered intensity profiling assessments that could reveal the effects of nail beautification on the nail plate. The formation and progression of cracks on the nail plate surface were detected as an effect of nail beautification after 72 h of nail-art removal. Changes in backscattered light intensity and nail plate thickness of control and art-removed nails were quantitatively compared. The results revealed the potential feasibility of the developed OCT-based inspection procedure to diagnose post-progressive nail-art effects on in vivo nail plate, which can be helpful to prevent nail plate damages during art removal through real-time monitoring of the boundary between the nail plate and nail-art. Besides nail-art effects, the developed method can also be used for the investigation of nail plate abnormalities by examining the inconsistency of internal and external nail plate structure, which can be diagnosed with both qualitative and quantitative assessments from a clinical perspective.