Category: Other Non-Medical

A fast imaging system that can reveal internal sample structures is important for research and quality controls of seeds. Optical coherence tomography (OCT) is a non-invasive optical imaging technique that can acquire high speed, high resolution depth-resolved images in scattering samples. It has found numerous applications in studying various biological tissues and other materials in vivo. A few studies have reported the use of OCT in studying seed morphology. However, 3D imaging of internal seed structure has not been reported before. In this study, we used a frequency domain OCT system to image tomato seeds. The system has a central ...

For twenty years Optical Coherence Tomography (OCT) has been interested in imaging in turbid media. Recently, conventional OCT has been extended to spectroscopic investigation (SOCT). For a full-field OCT configuration in the visible range, we show that the interference conditions are not equal in the whole field of view: the effective numerical aperture depends on the observation point. This results in a spectral shift towards higher wavelengths of the OCT spectra, leading to errors in spectroscopic analysis. We propose a general calibration method for SOCT measurements which has been tested within a protocol, to perform spatially-resolved spectroscopic identification of material ...

technique used for atomic-resolution protein-structure studies, and currently, robotic automation is often used to monitor and optimize crystallization conditions. However, it is often difficult to identify, by conventional light microscopy, crystals that can be used for X-ray crystallography when micro-size, needle, and salt crystals are also present in the crystallization medium.For the work reported herein, we demonstrated that micro-scale, non-invasive, three-dimensional (3D) cross-sectional, μm-resolution imaging of protein crystals could be achieved using optical coherence tomography (OCT).A wideband, ultra-high resolution, OCT spectrum (supercontinuum) was generated using an ultrashort laser pulse and optical fibers as the light source. Given the ...

Plants are one of the most fascinating and important groups of organisms living on Earth. They serve as the conduit of energy into the biosphere, provide food, and shape our environment. If we want to make headway in understanding how these essential organisms function and build the foundation for a more sustainable future, then we need to apply the most advanced technologies available to the study of plant life. In 2009, a committee of the National Academy highlighted the “understanding of plant growth” as one of the big challenges for society and part of a new era which they termed ...

Dr. David Smith from the University of Wisconsin-Madison recently published an interesting article that identifies an adaptation of optical coherence tomography to plasma turbulence measurements.  However the wavelength of the measurement was not at optical frequencies but rather high frequency microwaves (~300GHz).  Below is a summary of this interesting idea. Low coherence backscattering (LCBS) is a plasma turbulence measurement technique adapted from optical coherence tomography.  Calculations and simulations show LCBS measurements can achieve centimeter-scale spatial resolution using low coherence microwave radiation.  LCBS measurements exhibit several advantages over standard plasma turbulence measurement techniques including immunity to spurious reflections and measurement access ...

In this letter, a phase-sensitive, swept-source optical coherence tomography (SS-OCT) system is implemented for the optical measurement of nanostructures. A new approach is proposed to reduce the phase errors, resulting from trigger jitter of the swept source and the asynchronization between the A-scan trigger and OCT signal at the data acquisition end, with a narrowband fiber Bragg grating to generate the accurate A-scan trigger. Furthermore, combining the common-path configuration with the proposed approach, the displacement sensitivity can be calculated to be 80 pm when the swept source is operated at 30 kHz. Finally, the conducting glass was scanned with the ...

Optical coherence tomography (OCT) is an emerging optical imaging technique that is applied with low coherence interference to perform noninvasive, high-resolution images on internal and surface structures. In this study, we built an optical coherence system and developed a combined envelope-fringe and carrier-fringe technique that can take advantage of high-resolution and long-range for taking physical and environmental measurements. The proposed system demonstrated that the detection resolution of the changes of the refractive index was 1.89 × 10− 4 for the long-range set-up (i.e. using the envelope-fringe only), and 4.15 × 10− 5 for the high-resolution set-up (i.e. using ...

Micro-scale, non-invasive, three-dimensional cross-sectional imaging of protein crystals was successfully accomplished using ultra-high resolution optical coherence tomography (UHR-OCT) with low noise, Gaussian like supercontinuum. This technique facilitated visualization of protein crystals even those in medium that also contained substantial amounts of precipitates. We found the enhancement of the scattered signal from protein crystal by inclusion of agarose gel in the crystallization medium. Crystals of a protein and a salt in the same sample when visualized by UHR-OCT showed distinct physical characteristics, suggesting that protein and salt crystals may, in general, be distinguishable by UHR-OCT. UHR-OCT is a nondestructive and rapid ...

A common-path swept-source optical coherence tomography (SS-OCT) is a promising scheme for implementing a high-speed and stable OCT system. We investigate the capability of a common-path SS-OCT system to perform the cross-sectional imaging of valuable documents translated at high speed for the check of its security feature. The influence of transport speeds, up to 2000 mm/s, on the depth resolution and the signal intensity is experimentally evaluated using a SS-OCT system equipped with a swept source at a center wavelength of 1335 nm and with a sweep repetition rate of 50 kHz. The degradation of the measured signal is ...

The 3-dimensional imaging of complete polymer solar cells prepared by roll-to-roll coating was carried out using high-resolution 1322 nm optical coherence tomography (OCT) system. We found it possible to image the 3-dimensional structure of the entire solar cell that comprises UV-barrier, barrier material, adhesive, substrate and active solar cell multilayer structure. The achievable resolution was 12 μm in the lateral plane and 4.5 μm in the depth. We found that the OCT technique could be readily employed to identify coating defects in the functional layers. We finally identify the limitations of the technique, and future developments that would strengthen ...

The present invention relates to a noninvasive method and apparatus for screening seeds of high quality, which is capable of noninvasively distinguishing healthy and virus-free seeds from virus-infected seeds using an optical tomography technique. The noninvasive apparatus for screening seeds of high quality can screen seeds of high quality rapidly, simply, and accurately by: noninvasively capturing tomograms of seeds to be diagnosed by means of an optical coherence tomography machine; acquiring tomogram data of the seeds to be diagnosed by signal-processing an optical coherence signal from the captured tomogram; analyzing the acquired tomogram data to compare the analyzed tomogram data ...

We report a noble optical sensing method to diagnose seed abnormalities using optical coherence tomography (OCT). Melon seeds infected with Cucumber green mottle mosaic virus (CGMMV) were scanned by OCT. The cross-sectional sensed area of the abnormal seeds showed an additional subsurface layer under the surface which is not found in normal seeds. The presence of CGMMV in the sample was examined by a blind test (n = 140) and compared by the reverse transcription-polymerase chain reaction. The abnormal layers (n = 40) were quantitatively investigated using A-scan sensing analysis and statistical method. By utilizing 3D OCT image reconstruction, we confirmed the ...

The global citrus industry is continually confronted by new technological challenges to meet the ever-increasing consumer awareness and demand for quality-assured fruit. To face these challenges, recent trend in agribusiness is declining reliance on subjective assessment of quality and increasing adoption of objective, quantitative and non-destructive techniques of quality assessment. Non-destructive instrument-based methods are preferred to destructive techniques because they allow the measurement and analysis of individual fruit, reduce waste and permit repeated measures on the same item over time. A wide range of objective instruments for sensing and measuring the quality attributes of fresh produce have been reported. Among ...

Optical coherence tomography (OCT) is a relatively new imaging technology which can produce high resolution images of three-dimensional structures. OCT has been mainly used for medical applications such as for ophthalmology and dermatology. In this study we demonstrate its capability in providing much more reliable biometry identification of fingerprints than conventional methods. We prove that OCT can serve secure control of genuine fingerprints as it can detect if extra layers are placed above the finger. This can prevent with a high probability, intruders to a secure area trying to foul standard systems based on imaging the finger surface. En-Face OCT ...

The present invention relates to a non-invasive early diagnostic method and device that allows an early diagnosis of Marssonina blotch disease, which infects apple tree leaves, before the occurrence of lesions to enable early prevention of apple Marssonina blotch disease. The method and device of the present invention comprise the following steps: irradiating a broadband light source on an apple tree leaf undergoing diagnosis by means of optical coherence tomography; detecting interference signals from light reflected from the apple tree leaf undergoing diagnosis and light reflected from a reference arm; signal processing the interference signals, which have been detected through ...