Camera System Research Articles

Passive Stylus Tracking: A Systematic Literature Review

Passive stylus systems offer a simple and cost-effective solution for digital input, compatible with a wide range of surfaces and devices. This study reviews the domain of passive stylus tracking on passive surfaces, a topic previously underexplored in existing literature. We answer four key research questions: what type of systems exist in this domain, what methods do they use for tracking styli, how accurate are they, and what are their limitations? A systematic literature review resulted in 24 papers describing passive stylus systems. Their methods primarily fall into four categories: monocular cameras with image processing, multiple camera systems with image processing, machine learning systems using high-speed cameras or motion capture hardware, and radio frequency signal-based systems with signal processing. We found the system with the highest accuracy used a single monocular camera. In many systems, markers such as retroreflective spheres, tape, or fiducial markers were used to enhance the feature matching. We have also found stagnation and in some cases, regression in the precision and reliability of these systems over time. The limitations in these systems include the lack of varied stylus form factor support, the restriction to specific camera positions and angles, and the requirement of expensive hardware. Given these findings, we discuss the important characteristics and features of passive stylus systems and propose ways forward in this field.

Design of Exterior Orientation Parameters Variation Real-Time Monitoring System in Remote Sensing Cameras

The positional accuracy of satellite imagery is essential for remote sensing cameras. However, vibrations and temperature changes during launch and operation can alter the exterior orientation parameters of remote sensing cameras, significantly reducing image positional accuracy. To address this issue, this article proposes an exterior orientation parameter variation real-time monitoring system (EOPV-RTMS). This system employs lasers to establish a full-link active optical monitoring path, which is free from time and space constraints. By simultaneously receiving star and laser signals with the star tracker, the system monitors changes in the exterior orientation parameters of the remote sensing camera in real time. Based on the in-orbit calibration geometric model, a new theoretical model and process for the calibration of exterior orientation parameters are proposed, and the accuracy and effectiveness of the system design are verified by ground experiments. The results indicate that, under the condition of a centroid extraction error of 0.1 pixel for the star tracker, the EOPV-RTMS achieves a measurement accuracy of up to 0.6″(3σ) for a single image. Displacement variation experiments validate that the measurement error of the system deviates by at most 0.05″ from the theoretical calculation results. The proposed EOPV-RTMS provides a new design solution for improving in-orbit calibration technology and image positional accuracy.

Instance segmentation models for detecting floating macroplastic debris from river surface images

Quantifying the transport of floating macroplastic debris (FMPD) in waterways is essential for understanding the plastic emission from land. However, no robust tool has been developed to monitor FMPD. Here, to detect FMPD on river surfaces, we developed five instance segmentation models based on state-of-the-art You Only Look Once (YOLOv8) architecture using 7,356 training images collected via fixed-camera monitoring of seven rivers. Our models could detect FMPD using object detection and image segmentation approaches with accuracies similar to those of the pretrained YOLOv8 model. Our model performances were tested using 3,802 images generated from 107 frames obtained by a novel camera system embedded in an ultrasonic water level gauge (WLGCAM) installed in three rivers. Interestingly, the model with intermediate weight parameters most accurately detected FMPD, whereas the model with the most parameters exhibited poor performance due to overfitting. Additionally, we assessed the dependence of the detection performance on the ground sampling distance (GSD) and found that a smaller GSD for image segmentation approach and larger GSD for object detection approach are capable of accurately detecting FMPD. Based on the results from our study, more appropriate category selections need to be determined to improve the model performance and reduce the number of false positives. Our study can aid in the development of guidelines for monitoring FMPD and the establishment of an algorithm for quantifying the transport of FMPD.

Investigation of Arc Stability in Wire Arc Additive Manufacturing of 2319 Aluminum Alloy

Wire Arc Additive Manufacturing (WAAM) technology, known for its low equipment and material costs, high material utilization, and high production efficiency, has found extensive applications in the fabrication of key components for the aerospace and aviation industries. The stability of the arc is crucial for the WAAM process as it directly affects the forming of the parts. In this study, the monitoring data of electrical signals and arc morphology during the WAAM process of 2319 aluminum alloy were investigated using a high-speed camera system and current/voltage acquisition system. By analyzing the current and voltage signals, as well as the arc imaging results, the influence of arc stability on the forming of the cladding layer was studied. The experimental results indicated that when both current and voltage exhibit regular periodic fluctuations, this manifests as a stable short-circuit droplet transition form, while sudden changes in these signals represent abnormal droplet transition forms. The adaptability of the process directly influenced the arc shape, thereby affecting the forming of the cladding layer. Under the process parameters of welding speed of 240 cm/min and wire feeding speed of 6.5 m/min, it was observed that the current signal exhibited a tight state and the variance of the arc width was minimized. This indicated that at a higher wire feeding speed, the droplet transfer frequency was increased. Under these process parameters, the arc output was more stable, resulting in a uniform metal coating.

Detecting clinical medication errors with AI enabled wearable cameras

Drug-related errors are a leading cause of preventable patient harm in the clinical setting. We present the first wearable camera system to automatically detect potential errors, prior to medication delivery. We demonstrate that using deep learning algorithms, our system can detect and classify drug labels on syringes and vials in drug preparation events recorded in real-world operating rooms. We created a first-of-its-kind large-scale video dataset from head-mounted cameras comprising 4K footage across 13 anesthesiology providers, 2 hospitals and 17 operating rooms over 55 days. The system was evaluated on 418 drug draw events in routine patient care and a controlled environment and achieved 99.6% sensitivity and 98.8% specificity at detecting vial swap errors. These results suggest that our wearable camera system has the potential to provide a secondary check when a medication is selected for a patient, and a chance to intervene before a potential medical error.

Infrared thermography: An investigative tool for detection of subclinical bleed in hemophilia on prophylaxis

Background & objectives Subclinical joint bleed is a matter of concern in individuals with hemophilia on prophylaxis. Ultrasonography (USG) is mostly used for the screening of subclinical bleeds in such individuals but it has its own limitations. Thus a more comprehensive technology is required for the detection of the same. This study undertook to evaluate the efficacy of infrared thermography (IRT) for detection of subclinical joint bleeds and its comparison with ultrasonography and MRI (Magnetic Resonance Imaging), considering MRI as the gold standard. Methods Forty eight asymptomatic individuals with hemophiliacs on prophylaxis and 15 healthy males as controls were recruited. IRT, USG and MRI were done in all participants included in the study. FLIR camera systems were used for the capture of thermograms of the joints in both the study groups. Results The mean of maximum temperature difference>0.5K (ΔT max >0.5K) as compared to a healthy joint was considered as significant. Subclinical bleeds were detected in 23.9, 7.29 and 27.08 per cent participants by IRT, USG and MRI respectively. Sensitivity and specificity of IRT and USG was detected to be 88.4 and 97.67 per cent, and 26.9 and 99 per cent, respectively. Interpretation & conclusions The findings of this study suggest that IRT is an effective tool for detection of subclinical joint bleeds in individuals with hemophilia and can be used for the monitoring of the joints in such individuals.

A dual-biomimetic curved compound-eye camera system for multi-target distance measurement in a large field of view

A dual-biomimetic curved compound-eye camera system for multi-target distance measurement in a large field of view

In the arm-in-cage test, topical repellents activate mosquitoes to disengage upon contact instead of repelling them at distance

Topical repellents provide protection against mosquito bites and their efficacy is often assessed using the arm-in-cage test. The arm-in-cage test estimates the repellent’s protection time by exposing a repellent-treated forearm to host-seeking mosquitoes inside a cage at regular intervals until the first confirmed mosquito bite. However, the test does not reveal the repellents’ behavioural mode of action. To understand how mosquitoes interact with topical repellents in the arm-in-cage test, we used a 3D infrared video camera system to track individual Aedes aegypti and Anopheles stephensi females during exposure to either a repellent-treated or an untreated forearm. The repellents tested were 20% (m/m) ethanolic solutions of N, N-diethyl-meta-toluamide, p-menthane-3,8-diol, icaridin and ethyl butylacetylaminopropionate. All four repellents substantially reduced the number of bites compared to an untreated forearm, while the flight trajectories indicate that the repellents do not prevent skin contact as the mosquitoes made multiple brief contacts with the treated forearm. We conclude that, in the context of the arm-in-cage test, topical repellents activate mosquitoes to disengage from the forearm with undirected displacements upon contact rather than being repelled at distance by volatile odorants.

Spatiotemporal Information, Near-Field Perception, and Service for Tourists by Distributed Camera and BeiDou Positioning System in Mountainous Scenic Areas

The collaborative use of camera near-field sensors for monitoring the number and status of tourists is a crucial aspect of smart scenic spot management. This paper proposes a near-field perception technical system that achieves dynamic and accurate detection of tourist targets in mountainous scenic areas, addressing the challenges of real-time passive perception and safety management of tourists. The technical framework involves the following steps: Firstly, real-time video stream signals are collected from multiple cameras to create a distributed perception network. Then, the YOLOX network model is enhanced with the CBAM module and ASFF method to improve the dynamic recognition of preliminary tourist targets in complex scenes. Additionally, the BYTE target dynamic tracking algorithm is employed to address the issue of target occlusion in mountainous scenic areas, thereby enhancing the accuracy of model detection. Finally, the video target monocular spatial positioning algorithm is utilized to determine the actual geographic location of tourists based on the image coordinates. The algorithm was deployed in the Tianmeng Scenic Area of Yimeng Mountain in Shandong Province, and the results demonstrate that this technical system effectively assists in accurately perceiving and spatially positioning tourists in mountainous scenic spots. The system demonstrates an overall accuracy in tourist perception of over 90%, with spatial positioning errors less than 1.0 m and a root mean square error (RMSE) of less than 1.14. This provides auxiliary technical support and effective data support for passive real-time dynamic precise perception and safety management of regional tourist targets in mountainous scenic areas with no/weak satellite navigation signals.

CFD Analysis of Takeoff from a Water Surface for an Insect-Scale Aerial/Aquatic Robot

To develop an insect-scale aerial/aquatic robot, we analyzed takeoff mechanisms to counteract surface tension, such as paddling, slapping, and clap-and-fling. Because a diving beetle, Eretes griseus, takes off directly from the water surface, a flapping-wing robot is promising as an alternative to a drone with multiple rotary wings. In this study, we first investigated diving beetle flight with a three-dimensional high-speed camera system and analyzed the motion characteristics. Subsequently, we developed a computational fluid dynamics method that tracked the water surface using a volume of fluid method, reproduced the motion with a multibody model, treated the deformation of the elastic membrane wing with the phase delay of the joint angle functions, and simulated takeoff, that is, the transition from water to air, and hovering near the water surface. The simulation result showed that during the transition, the slapping motion exerted the maximum and average lift per unit of body weight of 18 and 9.2, respectively, while those of paddling produced 0.46 and 0.23, respectively. The water surface effect improved the lift by 25% at the normalized height of less than 0.44 and disappeared at a height greater than 0.7. During hovering, while the clap-and-fling motion improved lift by 2.6% and the water surface effect was 9.8%, the synergy effect was 22%. In addition, the former enhanced it significantly after the fling, while the latter was remarkable during the wing acceleration phase. In contrast to ground effects, flapping reduced the water level and caused the ripples, dynamically changing the water surface effect.

AI-Driven Mood Analysis for Employee Wellbeing: A Proactive Approach to Enhancing Workplace Productivity

This paper explores the implementation of an AI-enabled camera system to detect faces and analyze the mood, expressions, and mental health of employees as they enter the office. The data collected is stored in an Amazon S3 bucket and used to send personalized emails within the company, offering proactive wellbeing support sessions and tips to help employees improve productivity. This approach aims to enhance employee wellbeing and organizational performance through timely and tailored interventions.

Initial Characteristics of Submillimeter Metal Particles in GIS under Impact Vibration

As a critical component within power systems, Gas Insulated Switchgear (GIS) is notably susceptible to insulation degradation due to submillimeter metal particles, compromising its operational safety and stability. Moreover, impact vibrations induced by circuit breaker operations can dislodge particles that typically adhere to the interior walls, causing them to become airborne and thereby intensifying their movement and discharge activities. To investigate this phenomenon, this study establishes a testing platform where alternating current (AC) voltage is superimposed with impact vibration. A camera system, interfaced with an upper computer, is used to capture the real-time motion behavior of the particles. This study focuses on characterizing the initial movement of submillimeter metal particles of varying sizes under the influence of impact vibration by analyzing critical voltages, such as the initial lift-off voltage, stable jumping voltage, and extinction voltage. Furthermore, the effects of introducing large, centimeter-scale spherical metal and rubber particles on these initial characteristics are examined. The findings provide crucial insights into the initial behavior of submillimeter metal particles in GIS, particularly in relation to circuit breaker operations.

A Method for Tracking an Underwater Pipeline from Stereo Images Using an Autonomous Underwater Vehicle

The problem of tracking an underwater pipeline (UP) is considered in the context of an inspection mission. It is assumed that the diameter of the cylindrical pipe is known. To solve this problem, a tracking method is proposed, based on searching and calculating the center line of the UP, and determining the relative position of the autonomous underwater robot (AUV) and UP in the coordinate system of the AUV camera. Unlike well-known analogues, in which the solution is based on recognizing and constructing the boundaries of the UP in images, the proposed method searches for the true position of the center line of the UP on a set of possible options by checking their veracity. Possible options for the spatial position of the search centerline of the current UP section are generated by varying the direction of the beam in the horizontal and vertical plane. The starting point of the ray is the end point of the centerline of the previous section. The veracity criterion is to check that the 3D point features constructed in the scene belong to the cylindrical surface of the UP. The generation and matching of pointfeatures in images of a stereo pair is carried out using the SURF detector. The choice of the correct direction of the center line of the current UP section is ultimately made by voting. The end point of the center line of the current section is determined taking into account the calculated common visibility area with the previous section of the UP. To evaluate the effectiveness of the method, computational experiments were carried out on virtual scenes. The effectiveness was assessed by the accuracy of UP localization (in the AUV coordinate system) and by the speed of calculations in comparison with: a) the first version of this method, based on the use of a vectorized form of images; b) analogues using the Canny and Hough Transform detectors. The stability of the method to the accumulation of navigation accuracy errors during long-term tracking of UPs was also assessed.

Novel Approach for Lifetime-Proportional Luminescence Imaging Using Frame Straddling.

Optode-based chemical imaging is a rapidly evolving field that has substantially enhanced our understanding of the role of microenvironments and chemical gradients in biogeochemistry, microbial ecology, and biomedical sciences. Progress in sensor chemistry has resulted in a broadened spectrum of analytes, alongside enhancements in sensor performance (e.g., sensitivity, brightness, and photostability). However, existing imaging techniques are often costly, challenging to implement, and limited in their recording speed. Here we use the "frame-straddling" technique, originally developed for particle image velocimetry for imaging the O2-dependent, integrated luminescence decay of optical O2 sensor materials. The method synchronizes short excitation pulses and camera exposures to capture two frames at varying brightness, where the first excitation pulse occurs at the end of the exposure of the first frame and the second excitation pulse at the beginning of the second frame. Here the first frame truncates the luminescence decay, whereas the second frame fully captures it. The difference between the frames quantifies the integral of the luminescence decay curve, which is proportional to the luminescence lifetime, at time scales below one millisecond. Short excitation pulses avoid depopulation of the ground state of luminophores, resulting in a linear Stern-Volmer response with increasing concentrations of the quencher (O2), which can be predicted through a simple model. This methodology is compatible with a wide range of camera systems, making it a versatile tool for various optode based chemical imaging applications. We showcase the utility of frame straddling in measuring O2 dynamics around algae and by observing O2 scavenging sodium dithionite particles sinking through oxygenated water.

Application of digital transformation tools in dairy cattle farming and their role in improving population health and animal productivity

The aim of the study is to explore the ways of implementing digital technologies and modern technical solutions to ensure the population health of animals in the context of contemporary dairy farming. The paper discusses modern digital technical tools and automated processes in dairy farming facilitated by these tools. In the course of the study, the main tasks for successful digital transformation and ensuring the population health of animals in dairy farming were identified: searching for biomarkers of pathological and physiological states of animals, developing methods for determining found biomarkers, developing technical solutions for parameter registration and their implementation into production. At the moment, automatic systems for diagnosing the state of the animal’s body have been implemented using sound sensors, devices for determining the activity of the animal and the position of the body in space. Sensors for determining the electrical conductivity of milk make it possible to determine mastitis at the initial stage of the pathological process. Sensors for determining the concentration of hormones in milk make it possible to determine the period of the sexual cycle. ICS cameras allow you to determine areas of inflammation on the animal’s body. A modern 3-D camera system, combined with software, allows automatic measurement of animal body parameters on a daily basis. Thus, the implemented automated systems make it possible to reduce the time of human contact with an animal, which has a positive effect on the health of the animal. On the other hand, constant monitoring of important indicators of animal health allows timely detection of the onset of the disease. All of the above helps ensure population health on dairy farms.

Comparison and analysis of ophthalmic resources and service ability in Shanxi Province in 2014 and 2021

Objective: To compare and analyze the ophthalmic resources and service ability in Shanxi Province in 2014 and 2021, and to provide reference for the development planning of ophthalmology and eye care. Methods: In this cross-sectional study, a questionnaire survey was conducted among all ophthalmic institutions registered in the health administrative department in 11 cities of Shanxi Province by the end of 2014 and 2021 by using the National Ophthalmology Competency Resource Questionnaire (compiled by the Medical Administration and Hospital Authority of the National Health and Wellness Commission). The basic situations of ophthalmic institutions in 2014 and 2021, as well as the human resources, ophthalmic equipment configuration, technology and medical service capabilities, were recorded and compared. The chi-square test was used for statistical analysis. Results: A total of 270 questionnaires for 2014 were collected from 270 ophthalmic institutions, and 292 questionnaires for 2021 from 292 ophthalmic institutions. The institution categories in 2014 (197 general hospitals, 31 eye hospitals and 42 others) were statistically different from those in 2021 (182 general hospitals, 45 eye hospitals and 65 others) (P<0.05). The proportion of doctors with senior titles in ophthalmic institutions increased from 25.5% (346/1 358) in 2014 to 41.7% (580/1 391) in 2021, the proportion of senior technicians increased from 9.4% (14/148) to 25.3% (110/435), the proportion of doctors with junior titles decreased from 42.1% (572/1 358) to 26.5% (369/1 391), and the proportion of junior technicians decreased from 45.3% (67/148) to 39.1% (170/435). There was a significant difference in the distribution of professional titles between doctors and technicians in ophthalmic institutions (P<0.05). The number of doctors (130 to 28), nurses (152 to 50), technicians (33 to 11) and full-time optometrists (44 to 12) in the first-class ophthalmic institutions decreased, the increase of equipment with the ophthalmic A-ultrasound scan system, fundus camera and coherent optical tomography system (35.1%, 28.9% and 25.4%; P<0.05) ranked the top three, and the increase of performing the phacoemulsification procedure, intraocular lens implantation, intravitreal injection and iris surgery (30.2%, 24.7% and 20.7%; P<0.05) ranked the top three in 2021 as compared to 2014. Conclusions: The resources and service ability of ophthalmology in Shanxi Province developed in 2021 in comparison with 2014. However, there were some problems, such as changes in the type and structure of eye institutions, unreasonable proportions of professional titles, insufficient human resources in primary ophthalmic institutions, and slow improvement in the allocation of ophthalmology equipment and technical capabilities.

Intra-operative imaging solutions for surgeons

Intra-operative imaging solutions for surgeons Birgitta Dresp from the Centre National de la Recherche Scientifique (CNRS) discusses the challenges associated with intra-operative imaging technology and the quest for gold standards of surgical skill. In minimally invasive interventional procedures such as laparoscopic surgery, surgeons do not have a direct view of the organ or tissue they are interacting with but are constrained to navigate the surgical instruments on the basis of image views provided by dedicated camera systems. Image-guided interventions have been on the rise in recent years as they are less invasive than traditional methods and are believed to enable more accurate surgical gestures. Yet, the surgeon’s brain needs to re-interpret the visual information available in the image given. This has to be achieved swiftly and reliably for controlling the instruments with the greatest ease and accuracy, yielding the most precise surgical gestures in the shortest time possible. How can we assess critical parameters of surgical skill and its evolution with time and training under different conditions imposed by different technological solutions?

The Validity and Usability of Markerless Motion Capture and Inertial Measurement Units for Quantifying Dynamic Movements

ABSTRACT Purpose Motion capture technology is quickly evolving providing researchers, clinicians, and coaches with more access to biomechanics data. Markerless motion capture and inertial measurement units (IMUs) are continually developing biomechanics tools that need validation for dynamic movements before widespread use in applied settings. This study evaluated the validity of a markerless motion capture, IMU, and red, green, blue, and depth (RGBD) camera system as compared to marker-based motion capture during countermovement jumps, overhead squats, lunges, and runs with cuts. Methods Thirty adults were recruited for this study (sex: 18 females, 12 males; age: 25.4 ± 8.6 years; height: 1.71 ± 0.08 m; weight: 71.6 ± 11.5 kg). Data were collected simultaneously with four motion capture technologies (i.e., Vicon – marker-based, Theia/Optitrack – markerless, APDM Opals – IMUs, and Vald HumanTrak – RGBD camera). System validity for lower and upper body joint angles was evaluated using bias, root mean squared error (RMSE), precision, maximum absolute error, and intraclass correlation coefficients. System usability was descriptively analyzed. Results Overall, markerless motion capture had the highest validity (sagittal plane RMSE: 3.20-15.66°; frontal plane RMSE: 2.12-9.14°; transverse plane RMSE: 3.160-56.61°), followed by the IMU system (sagittal plane RMSE: 8.11-28.37°; frontal plane RMSE: 3.26-16.98°; transverse plane RMSE: 5.08-116.75°), and lastly the RGBD system (sagittal plane bias: 0.55-129.48°; frontal plane bias: 1.35-52.06°). Conclusions Markerless motion capture and IMUs have moderate validity for joint kinematics, while the RGBD system did not have adequate validity. Markerless systems have lower data processing time, require moderate technical expertise, but have high data storage size. IMUs are easier to use, can collect data in any location, but require participant set-up. Overall, individuals using motion capture should consider the specific movements, testing locations, and technical expertise available prior to selecting a system.

Flat mirrors, virtual rear-view cameras, and camera-mirror calibration

Flat mirrors are useful to generate virtual cameras and capture a scene from multiple viewpoints. However, the resultant camera-mirror setup is cumbersome to calibrate because of the mirror image reversion. The typical calibration flaws are omitting the checkerboard symmetry and assuming that virtual cameras are front-view. This paper explains the rear-view abstraction and its usefulness in calibrating a camera-mirror setup to obtain the equivalent mirrorless configuration. The underlying theory is reviewed, including camera imaging, the calibration process, and the laws of reflection. The proposed approach is illustrated by calibrating a camera-mirror setup and then using the calibrated camera to generate mirror images synthetically. This work offers a practical insight into calibrating more sophisticated systems such as mirrored camera-projector profilometers.

A study on in-situ characterization technology development for clearance verification of radioactive waste from nuclear decommissioning

Although the clearance level of every radioactive nuclide was published by the IAEA to promote the recycling and reuse of decontaminated radioactive waste worldwide, technical and regulatory issues have always been raised around the application of the criteria. Therefore, several countries are developing in-situ characterization equipment or apparatus for on-site verification to check if the clearance criteria is met.In this study authors developed a pilot radiation detection and measurement system using in-situ characterization technology to solve the issues, which consists of a 3D scanning camera system and a built-in Monte Carlo simulation program. Measurement results show that MDA (Minimum Detectable Activity) of the current design was indisputably below the clearance level and built-in Monte Carlo simulation package closely predicts the measurements results with the error of less than 5%. This implicates that it can determine with enough margin whether the radioactivity level of decontaminated metallic components meets the clearance criteria at decommissioning site or not.Practically when we measure the radioactivity from gamma ray source mass attenuation always takes place during the photon transports through the medium. In fact, the reduction depends on the material, shapes, and radioactive sources. In this study the reduction factors were experimentally examined according to the influencing parameters and the results were saved as DCF (Density Correction Factor) in the data base. As expected, it turned out that the factor is somewhat affected by medium material and radioactive sources, but it is basically proportional to the distance of gamma ray passage.It is expected that upgraded design with more accurate and reliable instruments can make it easier for regulators to accept the application of the in-situ characterization technology on-site.