Portable Imaging Research Articles

Using infrared thermal imaging technology to estimate the transpiration rate of citrus trees and evaluate plant water status

Crop transpiration is the main dissipation way of agricultural water. Accurate and effective estimation of crop transpiration is of great significance for the study of the carbon-water cycle relationship and efficient water-saving irrigation. This study uses infrared thermal imaging technology to accurately extract the average temperature of the plant canopy as a key input for the new model (three-dimensional temperature (3D-3T) model), which is an extension of the three-temperature (3T) model and applied to estimate the canopy transpiration rate of typical citrus trees (variety named Guoqing No. 1) from 8:00 to 18:00 on May 7 to 11, 2021. And a processing method for extracting green plants in visible-light images based on the Normalized Difference Ratio Index (NDRI) is proposed for the first time, which can distinguish green plants from other ground objects, backgrounds, and shadows in the visible-light image, and then help to accurately extract the average canopy temperature from infrared thermal images. For this experiment, the canopy structure characteristics of the selected experimental subjects and the measurement methods used were considered, so the 3D-3T model was converted to a 5-point three-temperature model (5P-3T model) to estimate the canopy transpiration rate of citrus trees and evaluate the plant water status, and then the sap flow measurement was used for validation. The results showed that: (1) The 3T model overestimated the transpiration rate of the citrus tree, while the 5P-3T model underestimated it. The estimated values of the 5P-3T model have a good correlation with the measured values of the packaged stem sap flow gauge method, with a determination coefficient (R2) of 0.72 and root mean square error (RMSE) of 0.35 mm/d. (2) In this model, the plant transpiration transfer coefficient (hat) can evaluate the water shortage of plants, where the value of hat increased with the aggravation of plant water stress. (3) The citrus trees have lower transpiration rates under water stress, ranging from 0.06 to 0.12 mm/h in the daytime (from 8-10 May 2021). The model used in this study only needs the input of temperature information and net radiation, and would not depend on aerodynamic resistance. The method in this paper can realize the non-contact and non-invasive measurement of crop transpiration, and it provides a feasible way to use a portable thermal imager to accurately obtain the temperature for estimating plant canopy transpiration rate.

Impact of flexible noise control (FNC) image processing parameters on portable chest radiography.

There is a lack of understanding in the performance of flexible noise control (FNC) processing, which is used in digital radiography on a scanner vendor and has four parameters each involving multiple options. The aim of this study was to investigate the impact of FNC on portable chest imaging. An anthropomorphic chest phantom was imaged using a clinical chest program with 85kV and five radiation dose levels at 40″ source-to-image distance with software-based scatter reduction method. All images were processed without and with FNC. Noise analysis was performed in two regions of interest (ROI) on subtracted noise-only images, and line profiles were generated through a lung-rib interface. In addition, noise power spectra (NPS) analysis was performed in solid water phantoms of 10 and 20cm thicknesses, using the same acquisition program and a range of dose levels. Last, feedback on retrospectively deidentified, reprocessed, and randomized clinical images from 20 portable chest exams was gathered from two thoracic radiologists. Noise reduction performances of FNC were demonstrated, with the level depending on specific FNC parameters, dose levels, ROI placement, and phantom sizes. Higher frequency textural patterns were revealed through the NPS analysis, which varied based on FNC parameters, dose levels, and phantom sizes. Overall, the vendor default parameter FGA0.5 yielded the highest noise reduction and textural artifacts. Radiologist feedback showed consistent preference of no FNC due to the presence of textural artifacts in the FNC-processed images. An algorithm improvement to avoid introducing artifacts would be desired.

Portable and low-cost hologram verification module using a snapshot-based hyperspectral imaging algorithm

One of the challenges in differentiating a duplicate hologram from an original one is reflectivity. A slight change in lighting condition will completely change the reflection pattern exhibited by a hologram, and consequently, a standardized duplicate hologram detector has not yet been created. In this study, a portable and low-cost snapshot hyperspectral imaging (HSI) algorithm-based housing module for differentiating between original and duplicate holograms was proposed. The module consisted of a Raspberry Pi 4 processor, a Raspberry Pi camera, a display, and a light-emitting diode lighting system with a dimmer. A visible HSI algorithm that could convert an RGB image captured by the Raspberry Pi camera into a hyperspectral image was established. A specific region of interest was selected from the spectral image and mean gray value (MGV) and reflectivity were measured. Results suggested that shorter wavelengths are the most suitable for differentiating holograms when using MGV as the parameter for classification, while longer wavelengths are the most suitable when using reflectivity. The key features of this design include low cost, simplicity, lack of moving parts, and no requirement for an additional decoding key.

Examination of the effectiveness of bedside nasojejunal tube placement using a portable imaging device with a flat panel detector.

Transporting pediatric patients with severe cardiovascular complications to the fluoroscopy room can be difficult. Therefore, we started using a portable imaging device with a flat panel detector (FPD) for nasojejunal tube (NJT) placement. The purpose of this study was to investigate the differences in length of time of NJT placement and dosage of radiation exposure using a portable imaging device with FPD versus fluoroscopy. Pediatric patients who underwent NJT placement between April 2016 and December 2018 were identified retrospectively from the clinical records. The age, sex, body weight, and height of each child at the time of the procedure as well as the procedure time, outcomes of the procedure, and dosage of radiation exposure was compared between the two groups. In 76 cases of NJT placement (41 patients), there was no significant difference in the success rate of NJT placement between the FPD (90%) and fluoroscopy groups (95%). However, the NJT placement time was significantly longer in the FPD group than in the fluoroscopy group (488 s vs 291 s). According to our calculations, the radiation dosage was lower in the FPD group than in the fluoroscopy group (136 μGy per procedure vs 2819 μGy per procedure). These results suggest that NJT placement using a portable imaging device with an FPD can be an effective method for children who are difficult to transport with an equal success rate and lower dosage of radiation exposure compared with conventional fluoroscopy.

Inference detection and classification of illicit drugs by a modest Raman spectrometer with a convolutional neural network analyzer

Faced with widespread of emerging new psychoactive substances (NPS) and illicit drugs, real-time and on-site detection techniques are urgently in need but remain a challenge. For this purpose, we present a simple but accurate in-house developed portable Raman spectral imaging system. The system consists of a compact, cost-effective and redesigned Raman spectrometer and a responsive analyzer for chemical compound identification based on convolutional neural network (CNN) techniques. To test the system, twelve substances are selected and divided into the library (established in database) and the challenge (unknown) groups. The challenge validation shows that the system achieves excellent predictive accuracy and high sensitivity even on low spectral resolution. The illicit drugs in the challenge set are identified as suspicious illicit compounds at an accuracy rate of about 92%. This accuracy results from that the spectral signatures of the functional groups or molecular structural similarities of the chemical compounds are recognized by the CNN model.

High-performance permanent magnet array design by a fast genetic algorithm (GA)-based optimization for low-field portable MRI

Lightweight and compact permanent magnet arrays (PMAs) are suitable for portable dedicated magnetic resonance imaging (MRI). It is worth exploring different PMA design possibilities and optimization methods with an adequate balance between weight, size, and performance, in addition to Halbach arrays and C-shaped/H-shaped magnets which are widely used. In this paper, the design and optimization of a sparse high-performance inward-outward ring-pair PMA consisting of magnet cuboids is presented for portable imaging of the brain. The design is lightweight (151kg) and compact (inner bore diameter: 270mm, outer diameter: 616mm, length: 480mm, 5-Gauss range: 1840×1840×2340mm3). The optimization framework is based on the genetic algorithm with a consideration of both field properties and simulated image quality. The resulting PMA design has an average field strength of 101.5 mT and a field pattern with a built-in linear readout gradient. Subtracting the best fit to the linear gradient target resulted in a residual deviation from the target field of 0.76mT and an average linear regression coefficient of 0.85 to the linear gradient. The required radiofrequency bandwidth is 6.9% within a field of view (FoV) with a diameter of 200mm and a length of 125mm. It has a magnetic field generation efficiency of 0.67mT/kg, which is high among the sparse PMAs that were designed for an FoV with a diameter of 200mm. The field can be used to supply gradients in one direction working with gradient coils in the other two directions, or can be rotated to encode signals for imaging with axial slice selection. The encoding capability of the designed PMA was examined through the simulated reconstructed images. The force experienced by each magnet in the design was calculated, and the feasibility of a physical implementation was confirmed. The design can offer an increased field strength, and thus, an increased signal-to-noise ratio. It has a longitudinal field direction that allows the application of technologies developed for solenoidal magnets. This proposed design can be a promising alternative to supplying the main and gradient fields in combination for dedicated portable MRI. Lastly, the design is resulted from a fast genetic algorithm-based optimization in which fast magnetic field calculation was applied and high design flexibility was feasible. Within optimization iterations, image quality metrics were used for the encoding field of a magnet configuration to guide the design of the magnet array.

First clinical applications for the NIR-II imaging with ICG in microsurgery.

In microsurgery, it is always difficult to accurately identify the blood supply with ease, such as vascular anastomosis, digit replantation, skin avulsion reconstruction and flap transplantation. Near-infrared window I (NIR-I, 700-900nm) imaging has many clinical applications, whereas near-infrared window II (NIR-II, 1,000-1700nm) imaging has emerged as a highly promising novel optical imaging modality and used in a few clinical fields recently, especially its penetration distance and noninvasive characteristics coincide with the needs of microsurgery. Therefore, a portable NIR-II imaging instrument and the Food and Drug Administration (FDA) approved indocyanine green (ICG) were used to improve the operation efficiency in microsurgery of 39 patients in this study. The anastomotic vessels and the salvaged distal limbs were clearly visualized after intravenous injection of ICG. The technique enabled identification of perforator vessels and estimation of perforator areas prior to the flap obtention and made it easier to monitor the prognosis. Overall, this study highlights the use of the portable NIR- II imaging with ICG as an operative evaluation tool can enhance the safety and accuracy of microsurgery.

Quantitative tumor depth determination using dual wavelength excitation fluorescence.

Quantifying solid tumor margins with fluorescence-guided surgery approaches is a challenge, particularly when using near infrared (NIR) wavelengths due to increased penetration depths. An NIR dual wavelength excitation fluorescence (DWEF) approach was developed that capitalizes on the wavelength-dependent attenuation of light in tissue to determine fluorophore depth. A portable dual wavelength excitation fluorescence imaging system was built and tested in parallel with an NIR tumor-targeting fluorophore in tissue mimicking phantoms, chicken tissue, and in vivo mouse models of breast cancer. The system showed high accuracy in all experiments. The low cost and simplicity of this approach make it ideal for clinical use.

Imaging three dimensional objects with ultrasound

The ultrasound imaging laboratory provided students with the opportunity of determining what an unknown three dimensional object was from two-dimensional images. Armed with a portable diagnostic ultrasound imaging system, and internal calipers for quantification, students were given unknown objects from the creepy crawly collection. Each object was immersed in a small tub of opaque fluid. Students could adjust the imaging system to give different cross-sections or cut planes through the object. From this information and linear calipers, they were to determine what the object was and provide a quantitative three dimensional sketch. This experience gave them a taste of the chief difficulty in diagnostic imaging of the body: deciphering and recognizing tissue structures and organs from partial views. Other imaging exercises included the use of imaging phantoms to measure spatial and temporal resolution as a function of depth and other controls.

130 Novice-Performed Point-of-Care Ultrasound for Home-Based Imaging

As delivering health care in alternative settings becomes more common, portable imaging technologies aiding medical decision-making will be key. Patient-performed point-of-care ultrasound (POCUS) scanning may be feasible for use in home-based medical care. Here, we investigated whether novice users can obtain lung ultrasound (LUS) images via self-scanning with similar interpretability and quality as experts.

Artificial intelligence (AI) based system for the diagnosis and classification of scalp health: AI-ScalpGrader

Many people suffer from scalp disorders but common treatment devices have faults such as inaccuracy of results and inconvenience of use. This study proposes a deep learning-based intelligent scalp diagnosis and classification system, named artificial intelligence (AI)-ScalpGrader. The proposed system consists of a portable scalp imaging device (ASM-202), a mobile device app, a cloud-based AI training server, and a cloud-based management platform. The instrumentation diagnoses and classifies ten scalp symptoms (normal, drying, oily, sensitivity, atopy, seborrheic, trouble, dry dandruff, oily dandruff, and hair loss) based on seven dermatologist-based indices (microkeratin, sebaceous, erythema between hair follicles, follicular erythema/pustules, dandruff, and hair loss) by AI-based characterization of the symptoms and indices. EfficientNet, a convolutional neural network (CNN) learning model, is MBConvolution composed with depthwise convolution, squeeze excitation, and width scaling and was adopted to diagnose and classify scalp conditions through retraining of images in the system. The results and verification on the reliability of AI-based data show that the system is able to diagnose and classify these symptoms and severity of the indices with accuracy values from 87.3 to 91.3%. Therefore, the AI-ScalpGrader is a novel approach to diagnose and classify scalp status.

Visible spectral imaging (443–726 nm) for evaluating ultraviolet decontamination and predicting bacterial spoilage of vacuum packed chicken breasts

This work used portable spectral imaging to assess effects of ultraviolet (UV) (254 nm) decontamination and predict bacterial spoilage of vacuum packaged chicken breasts. Samples were scanned using spectral imaging, sampled for colour (L* - lightness, a* - redness, b* - yellowness), pH, total viable (TVC) and total Enterobacteriaceae counts (TEC) over 12 days of storage at 4 °C. UV treated samples had mean a* values 0.42 units significantly higher than untreated controls (p < 0.05). UV treatment affected the spectra of samples, allowing for discrimination between treatment types using Partial least squares discriminant analysis (PLS-DA) (CC%test = 97.5%). Values of TEC and TVC were significantly reduced by UV treatment and the effects remained significant over the storage time (p < 0.05), extending bacterial shelf life by 3 days. Partial least squares regression (PLSR) models were built from the measured spectra to predict TEC (Rp2 = 0.66, RMSEP = 0.63 log CFU/g) and TVC (Rp2 = 0.78, RMSEP = 0.87 log CFU/g). Interpretation of the spectra strongly suggested that UV treatment affected oxymyoglobin concentrations by accelerating myoglobin oxidation. However, despite differences in oxymyoglobin concentrations, it was still possible to build models using spectral data that could reasonably predict microbiological spoilage.

Deep learning and multiwavelength fluorescence imaging for cleanliness assessment and disinfection in Food Services

Precise, reliable, and speedy contamination detection and disinfection is an ongoing challenge for the food-service industry. Contamination in food-related services can cause foodborne illness, endangering customers and jeopardizing provider reputations. Fluorescence imaging has been shown to be capable of identifying organic residues and biofilms that can host pathogens. We use new fluorescence imaging technology, applying Xception and DeepLabv3+ deep learning algorithms to identify and segment contaminated areas in images of equipment and surfaces. Deep learning models demonstrated a 98.78% accuracy for differentiation between clean and contaminated frames on various surfaces and resulted in an intersection over union (IoU) score of 95.13% for the segmentation of contamination. The portable imaging system’s intrinsic disinfection capability was evaluated on S. enterica, E. coli, and L. monocytogenes, resulting in up to 8-log reductions in under 5 s. Results showed that fluorescence imaging with deep learning algorithms could help assure safety and cleanliness in the food-service industry.

Cost-efficient analysis of a portable low field magnetic resonance imaging system for prostate cancer diagnosis

PurposeMagnetic resonance imaging (MRI)-guided procedures are typically performed under high magnetic field strengths (1.5-3 Tesla) and are expensive. Recently, technological progress has led to MRIs that are low-cost but similarly high performing despite lower field strengths (58-74mT). Our purpose was to evaluate the cost-efficiency of implementing a low-field MRI for targeted prostate cancer biopsy.Materials and methodsWe utilized time-driven activity-based costing (TDABC) to establish the overall costs based on cost rates and total times for every step. Thorough literature searches and consultations with two board certified radiologists, the process maps were created, and the duration of each step was determined by experience and previously published data. A sensitivity cost analysis was also performed to create several cost scenarios for the low-field MRI system.ResultsTotal procedure times, performed under moderate sedation, were 61 ± 14.5 mins and 57 ± 23 mins for transperineal targeted biopsy (TPB) with low-field MRI and in-bore MRI-guided transrectal biopsy (IB-TBx) with high-field MRI. In the low-field MRI pathway, 61% of intra-operative time was spent on patient preparation and performing the prebiopsy MRI, however, this step did not require a urologist or radiologist expertise, subsequently keeping costs lower. A sensitivity analysis of the low-field MRI cost at 5% to 50% (in 5% increments) of a high-field MRI produced a difference from $888.13 to $879.18 favoring the lower-field system, respectively.ConclusionsA portable, low field, office-based MRI system offers a cost-efficient alternative to the high-field MRI. Further studies assessing cost effectiveness while taking into consideration sampling accuracy are needed.

Ultrasound may safely replace chest radiograph after tube thoracostomy removal in trauma patients

IntroductionA chest radiograph (CXR) is routinely obtained in trauma patients following tube thoracostomy (TT) removal to assess for residual pneumothorax (PTX). New literature supports the deference of a radiograph after routine removal procedure. However, many surgeons have hesitated to adopt this practice due to concern for patient welfare and medicolegal implications. Ultrasound (US) is a portable imaging modality which may be performed rapidly, without radiation exposure, and at minimal cost. We hypothesized that transitioning from CXR to US following TT removal in trauma patients would prove safe and provide superior detection of residual PTX. Materials and MethodsA practice management guideline was established calling for the performance of a CXR and bedside US 2 h after TT removal in all adult trauma patients diagnosed with PTX at a level 1 trauma center. Surgical interns completed a 30-minute, US training course utilizing a handheld US device. US findings were interpreted and documented by the surgical interns. CXRs were interpreted by staff radiologists blinded to US findings. Data was retrospectively collected and analyzed. ResultsEighty-nine patients met inclusion criteria. Thirteen (15%) post removal PTX were identified on both US and CXR. An additional 11 (12%) PTX were identified on CXR, and 5 (6%) were identified via US, for a total of 29 PTX (33%). One patient required re-intervention; the recurrent PTX was detected by both US and CXR. For all patients, using CXR as the standard, US displayed a sensitivity of 54.2%, specificity of 92.3%, negative predictive value of 84.5%, and positive predictive value of 72.2%. The cost of care for the study cohort may have been reduced over $9,000 should US alone have been employed. ConclusionBedside US may be an acceptable alternative to CXR to assess for recurrent PTX following trauma TT removal.

Evaluation of the Influence of Short Tourniquet Ischemia on Tissue Oxygen Saturation and Skin Temperature Using Two Portable Imaging Modalities.

Background: The exact influence of tourniquet ischemia on a treated extremity remains unclear. Methods: Twenty patients received an operation on one hand under tourniquet ischemia. Twenty healthy volunteers received 10 min of tourniquet ischemia on one of their arms. Measurements of tissue oxygen saturation using near-infrared reflectance-based imaging and skin temperature of the dorsum of the hand were performed at five different timepoints (t0 was performed just before the application of the tourniquet ischemia, t1 directly after the application of the tourniquet ischemia, t2 before the release of the ischemia, t3 directly after the release of the ischemia, and t4 on the following day). Results: In both groups, tissue oxygen saturation dropped after the application of the tourniquet ischemia compared to t0 and increased after the release of the tourniquet ischemia. In the patient group, tissue oxygen saturation at t4 was higher compared to t0; in contrast, the level of tissue oxygen saturation in the participant group dropped slightly at t4 compared to t0. The measured skin temperature in the patient group showed an increase during the observation period, while it continuously decreased in the group of healthy participants. Conclusions: Short-term ischemia did not appear to permanently restrict perfusion in this study design. The non-invasive imaging modalities used were easy to handle and allowed repetitive measurement.

Preparation of new flexible antenna based on sol–gel synthesized MgxCa(0.9-x)Zn0.10Fe2O4 nanoparticle for microwave imaging applications

This article prepares, MgxCa(0.90-x)Zn0.10Fe2O4 nanoparticle-based new flexible microwave substrate materials to build flexible antennas. The MgxCa(0.90-x)Zn0.10Fe2O4 nanoparticles are synthesized using the sol–gel chemical method. There are three different weight percentages are chosen for “X” values i.e., X = 25%, 50%, and 75%. X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), and transmission electron microscopy (TEM) studies are used to evaluate the structural and morphological features of the produced nanoparticles. Dielectric Assessment Kit is also used to evaluate the nanoparticles' tunable dielectric characteristics (DAK). Loss tangents range from 0.00275 to 0.00675 while dielectric permittivity values range from 3.25 to 4.75. The magnetic characteristics of the produced samples are also investigated using the vibrating sample magnetometer (VSM). The Agilent 8501E module is used to calculate the adjustable magnetic permeability and magnetic loss tangent values. The magnetic permeability and magnetic loss tangent values obtained are in the range of 1.00–1.15 and 0.0035–0.0065, respectively. Later, a flexible antenna is designed on the prepared flexible substrate that operates within the frequency range of 1.60 GHz–3.00 GHz with a maximum gain of 5.15 dBi. After that, this antenna is incorporated with a nine-antenna array-based portable microwave head imaging system. Finally, successful brain tumor detection is observed by post-processing the collected scattering parameters with an image reconstruction algorithm. The overall results ensure that the MgxCa(0.90-x)Zn0.10Fe2O4 nanoparticle-based new flexible microwave substrate materials can be a potential candidate for microwave head imaging and are suitable to fit with microwave devices.

Portable Bone Imaging Devices for Screening and Diagnosing Osteoporosis

&#x0D; Limited evidence describing the clinical utility of 2 types of portable bone imaging devices suggest that they may be comparable to DXA for predicting the incidence of fracture, but the findings are uncertain.&#x0D; Incorporating 1 type of portable bone imaging device into a screening and diagnosis management pathway for osteoporosis was more cost-effective in a Finnish context, compared to an osteoporosis management approach that did not include the portable bone imaging device.&#x0D; Two guidelines were found that have recommendations about portable bone imaging devices for screening and diagnosing osteoporosis. Both guidelines reported limited evidence on the use of portable bone imaging devices.&#x0D;

Automated Recognition of Plasmodium falciparum Parasites from Portable Blood Levitation Imaging.

In many malaria‐endemic regions, current detection tools are inadequate in diagnostic accuracy and accessibility. To meet the need for direct, phenotypic, and automated malaria parasite detection in field settings, a portable platform to process, image, and analyze whole blood to detect Plasmodium falciparum parasites, is developed. The liberated parasites from lysed red blood cells suspended in a magnetic field are accurately detected using this cellphone‐interfaced, battery‐operated imaging platform. A validation study is conducted at Ugandan clinics, processing 45 malaria‐negative and 36 malaria‐positive clinical samples without external infrastructure. Texture and morphology features are extracted from the sample images, and a random forest classifier is trained to assess infection status, achieving 100% sensitivity and 91% specificity against gold‐standard measurements (microscopy and polymerase chain reaction), and limit of detection of 31 parasites per µL. This rapid and user‐friendly platform enables portable parasite detection and can support malaria diagnostics, surveillance, and research in resource‐constrained environments.

A Solar-Blind Perovskite Scintillator Realizing Portable X-ray Imaging

A portable X-ray imaging technique involves conducting a quick response to a target outdoors, which is of great importance for active diagnosis and prompt treatment. However, realizing portable X-ray imaging in terms of equipment miniaturization, image visualization, and the crosstalk of external light signals remains a challenge. Herein, we demonstrate the feasibility of utilizing a lead-free perovskite scintillator (Cs2ZrCl6: Lu3+) for exploring portable X-ray imaging under sunlight without the need for complex imaging devices. Our experiments verify that the ultrabright radioluminescence (347 lm m–2, ∼20 times greater than that of the commercial single-crystal scintillator Bi4Ge3O12) originates from the effective activation of triplet excitons (dark state) of the as-developed scintillator, which is unresponsive to UV and visible photons. Moreover, brightening of dark-state excitons is accelerated via the manipulation of the introduced lanthanide ions. These results highlight the importance of harvesting and taking advantage of engineering dark-state excitons, which is incentive for future research in low-cost X-ray detection for portable, fast-response radiography.