Development of a simultaneous imaging system to measure the optical and gamma ray images of Ir-192 source for high-dose-rate brachytherapy

In high-dose-rate (HDR) brachytherapy, verification of the Ir-192 source's position during treatment is needed because such a source is extremely radioactive. One of the methods used to measure the source position is based on imaging the gamma rays from the source, but the absolute position in a patient cannot be confirmed. To confirm the absolute position, it is necessary to acquire an optical image in addition to the gamma ray image at the same time as well as the same position. To simultaneously image the gamma ray and optical images, we developed an imaging system composed of a low-sensitivity, high-resolution gamma camera integrated with a CMOS camera. The gamma camera has a 1-mm-thick cerium-doped yttrium aluminum perovskite (YAIO3: YAP(Ce)) scintillator plate optically coupled to a position-sensitive photomultiplier (PSPMT), and a 0.1-mm-diameter pinhole collimator was mounted in front of the camera to improve spatial resolution and reduce sensitivity. We employed the concept of a periscope by placing two mirrors tilted at 45 degrees facing each other in front of the gamma camera to image the same field of view (FOV) for the gamma camera and the CMOS camera. The spatial resolution of the imaging system without the mirrors at 100 mm from the Ir-192 source was 3.2 mm FWHM, and the sensitivity was 0.283 cps/MBq. There was almost no performance degradation observed when the mirrors were positioned in front of the gamma camera. The developed system could measure the Ir-192 source positions in optical and gamma ray images. We conclude that the developed imaging system has the potential to measure the absolute position of an Ir-192 source in real-time clinical measurements.

Design and construction of hardware and software for autonomous observations of Transient Luminous Events

Transient luminous events (TLE) are phenomena which are currently on the rise in terms of sightings. However, there is no widespread uniform method of their observation and subsequent image processing. Therefore, our project focuses on the design and construction of hardware that can record TLE. It consists of a low gain, colour, CMOS camera with a bright, wide lens connected to a small, power-efficient single board computer. The project also includes writing software to control the hardware. The software decides whether to capture or not and at what orientation there is the biggest chance to capture a TLE. The software can process and classify the created photos based on deep neural networks. As a final product, we have developed the whole apparatus from a hardware and software point of view and installed it at the Astronomical Observatory at Kolonica Saddle in Slovakia, Central Europe. The plan for the future is to make similar apparatuses to spread the observation network.

A rapid and non-destructive method for spatial–temporal quantification of colonization by Pseudomonas syringae pv. tomato DC3000 in Arabidopsis and tomato

Background The bacterial leaf pathogen Pseudomonas syringae pv tomato (Pst) is the most popular model pathogen for plant pathology research. Previous methods to study the plant-Pst interactions rely on destructive quantification of Pst colonisation, which can be labour- and time-consuming and does not allow for spatial–temporal monitoring of the bacterial colonisation. Here, we describe a rapid and non-destructive method to quantify and visualise spatial–temporal colonisation by Pst in intact leaves of Arabidopsis and tomato. Results The method presented here uses a bioluminescent Pst DC3000 strain that constitutively expresses the luxCDABE operon from Photorhabdus luminescens (Pst::LUX) and requires a common gel documentation (Gel Doc) system with a sensitive CCD/CMOS camera and imaging software (Photoshop or Image J). By capturing bright field and bioluminescence images from Pst::LUX-infected leaves, we imaged the spatiotemporal dynamics of Pst infection. Analysis of bioluminescence from live Pst bacteria over a 5-day time course after spray inoculation of Arabidopsis revealed transition of the bacterial presence from the older leaves to the younger leaves and apical meristem. Colonisation by Pst:LUX bioluminescence was obtained from digital photos by calculating relative bioluminescence values, which is adjusted for bioluminescence intensity and normalised by leaf surface. This method detected statistically significant differences in Pst::LUX colonisation between Arabidopsis genotypes varying in basal resistance, as well as statistically significant reductions in Pst::LUX colonisation by resistance-inducing treatments in both Arabidopsis and tomato. Comparison of relative bioluminescence values to conventional colony counting on selective agar medium revealed a statistically significant correlation, which was reproducible between different Gel Doc systems. Conclusions We present a non-destructive method to quantify colonisation by bioluminescent Pst::LUX in plants. Using a common Gel Doc system and imaging software, our method requires less time and labour than conventional methods that are based on destructive sampling of infected leaf material. Furthermore, in contrast to conventional strategies, our method provides additional information about the spatial–temporal patterns of Pst colonisation.

Real-time profilometry by bicolor grating video projection

A novel real-time 2+1 three-dimensional(3D) measuring method based on bicolor grating video projection is proposed. Firstly, only two frames of bicolor gratings, in which the red channels are two sinusoidal fringes with a shifting phase of π/2 and the blue channels are the same background light equivalent to the DC component of the two sinusoidal fringes are encoded and arranged alternatively to synthesize into a repetitive bicolor grating video, While this video is projected onto the measured object, the real-time bicolor deformed pattern video can be recorded by using a color CMOS camera, and the bicolor deformed pattern sequence at different moments can be extracted by computer processing, so that the 2+1 algorithm can be used to accomplish real-time 3D measurement of moving object. Before measuring, we used the same method to design two sinusoidal fringes with a difference of π in their red channels, respectively, to calibrate the sensitivity ratio between the red and blue channels of the CMOS camera, which can effectively eliminate the chromaticity imbalance between R and B channels and reduce the color crosstalk. Experimental results and analysis confirm the feasibility and effectiveness of the proposed method. Because the proposed method needs a repetitive bicolor grating video synthesized with only two-frame bicolor gratings to be projected, the 3D measurement acquisition speed and real-time accuracy will be improved compared with the traditional 2+1 3D measuring method.

First Demonstration of Calibrated Color Imaging by the CAOS Camera

The Coded Access Optical Sensor (CAOS) camera is a novel, single unit, full spectrum (UV to short-wave IR bands), linear, high dynamic range (HDR) camera. In this paper, calibrated color target imaging using the CAOS camera and a comparison to a commercial HDR CMOS camera is demonstrated for the first time. The first experiment using a calibrated color check chart indicates that although the CMOS sensor-based camera has an 87 dB manufacturer-specified HDR range, unrestricted usage of this CMOS camera’s output range greatly fails quality color recovery. On the other hand, the intrinsically linear full dynamic range operation CAOS camera color image recovery generally matches the restricted linear-mode commercial CMOS sensor-based camera recovery for the presented 39.5 dB non-HDR target that also matches the near 40 dB linear camera response function (CRF) range of the CMOS camera. Specifically, compared to the color checker chart manufacturer provided XYZ values for the calibrated target, percentage XYZ mean errors of 8.3% and 10.9% are achieved for the restricted linear range CMOS camera and CAOS camera, respectively. An alternate color camera assessment gives CIE ΔE00 mean values of 4.59 and 5.7 for the restricted linear range CMOS camera and CAOS camera, respectively. Unlike the CMOS camera lens optics and its photo-detection electronics, no special linear response optics and photo-detector designs were used for the experimental CAOS camera, nevertheless, a good and equivalent color recovery was achieved. Given the limited HDR linear range capabilities of a CMOS camera and the intrinsically wide linear HDR capability of a CAOS camera, a combined CAOS-CMOS mode of the CAOS smart camera is prudent and can empower HDR color imaging. Applications for such a hybrid camera includes still photography imaging, especially for quantitative imaging of biological samples, valuable artworks and archaeological artefacts that require authentic color data generation for reliable medical decisions as well as forgery preventing verifications.

Development of GIS Switch State Judgment System Based on Image Recognition

Aiming at the fast opening and closing speed of the GIS isolation/grounding switch, manual observation is more difficult, so it is difficult to judge the current switch status. This paper proposes an OpenCV-based image identification algorithm to identify the position of the switch movable contact during the opening and closing process of the isolating switch, thereby judging the state of the isolating switch. This system uses Raspberry Pi as the main hardware core, the server drives the CMOS camera through Raspberry Pi 4B, collects image information in the GIS optical observation window, and performs simple processing, and transmits it to the Raspberry Pi 4B based on the UDP protocol as the main core. In the upper computer and adopt the target detection algorithm based on OpenCV to track the current isolation/grounding switch contact position and determine the current opening and closing state.

Design of a Surgical Pen-Type Probe for Real-Time Indocyanine Green Fluorescence Emission Diagnosis

The advantage of handheld type surgical microscope is that the size of the probe is small and light, and the working distance(o to 30 cm) and field of view (306°) can be adjusted. Also, a short working distance will minimize the loss of light source energy. However, the currently developed handheld type surgical microscope is still large, heavy, and uses relatively high energy (600 mW). Also, it is not suitable for portable use. To address the aforementioned problems, this study aimed to develop a pen-type surgical fluorescence microscope that is compact, portable, and has an adjustable beam angle and working distance. The pen-type probe consists of a laser diode, CMOS camera, light source brightness control device, filter, and power switch. The IR-cut filter inside the CMOS camera was removed to facilitate transmission of the fluorescence emission wavelength. In addition, a long-pass filter was attached to the camera so that the external light source was blocked and only the fluorescence emission wavelength was allowed to pass through. The pen-type probe was manufactured using 3D printing, and the captured image was designed to be observed through an external monitor. The performance of the pen-type probe was tested through a large animal experiment. Indocyanine green (2.5mg/kg) was injected into a pig's vein. Fluorescence emission of 805-830 nm was achieved by irradiating an external light source (785 nm and 4 mW/cm2), and liver-uptake occurred after 2.4 minutes.

The visibility and stability of GaSe nanoflakes of about 50 layerson SiO2/Si wafers

GaSe nanoflakes on silicon substrates covered by SiO2 films are prepared by mechanical exfoliation from the bulk Bridgman-grown GaSe crystals using a scotch tape. The thickness of SiO2 films on Si substrates providing the highest optical contrast for observation of GaSe flakes is estimated by taking into account the spectral sensitivity of a commercial CMOS camera and broadband visible light illumination. According to our estimations, the optimal SiO2 thickness is [Formula: see text]126 nm for the visualization of GaSe flakes of 1–3 layers and [Formula: see text]100 nm for the flakes of 40–70 layers. The obtained nanoflakes are investigated by optical and atomic force microscopy and Raman spectroscopy. The observed spectral positions of the Raman peaks are in agreement with the positions of the peaks known for bulk and nanolayered GaSe samples. It is found that the 50 nm thick flakes are stable but are covered by oxide structures with lateral size about 100 nm and height [Formula: see text]5 nm after [Formula: see text]9 months exposure to ambient atmosphere.