Adaptive milliseconds tracking and zooming optics based on a high-speed gaze controller and liquid lenses.

The high-speed gaze and high resolution are critical factors for actual monitoring systems. However, the conventional method cannot track and zoom as fast as expected due to the larger inertia and it results in a low resolution due to the digital zoom. In this paper, we proposed a high-speed tracking and zooming optics that is coaxial designed and with an active tracking unit and an optical zooming unit to overcome the above issues. The tracking unit always tracks the object in the center of view by a pan-tilt mirror controller and a visual feedback tracking algorithm within 4 milliseconds response order. The zooming unit can continuously change the magnification from 1X to 2X by three liquid lenses within milliseconds. Besides, the zooming unit provides a compensation algorithm to achieve accurate zoom and focus.

Dynamic depth-of-field projection mapping method based on a variable focus lens and visual feedback.

Dynamic projection mapping is an interactive display technology, which is capable with multiplayers with naked eyes for augmented reality. However, the fixed and shallow depth-of-field of the projector optics limits its potential applications. In this work, a high-speed projection mapping method with a dynamic focal tracking technology based on a variable focus lens will be illustrated. The proposed system included a high-speed variable focus lens, a high-speed camera, and a high- speed projector, so that the depth and rotation information would be detected and then served as feedback to correct the focal length and update the projection information in real time. As a result, the information would be well-focused projected even on a 3D dynamic moving object. The response speed of the high-speed prototype could reach around 5 ms, and the dynamic projection range covered from 0.5 to 2.0 m.

Hybrid surface measuring system for motion-blur compensation and focus adjustment using a deformable mirror.

The recent growth in automation and microfabrication has led to a need for faster, more accurate inspections. This in turn requires fast and accurate image capture methods. A system has previously been proposed to obtain images without motion blur by controlling the line of sight to follow a moving object with a mirror, thereby decreasing inspection time. However, as this system follows only the line of sight, it corresponds only to the plane parallel to the direction of movement. Here, we propose a system for measuring non-planar surfaces by simultaneously controlling the line of sight and focus using a deformable mirror. In addition, the proposed system requires only one deformable mirror, whereas those from previous studies require multiple devices to control the line of sight and focus. Therefore, our proposed system can be downsized and applied to various measurement systems. We tested our system by measuring surface images of objects with curved and uneven surfaces under movement at 20 mm/s, at a distance of about 140 mm in front of the mirror. The system successfully obtained motion-blur-free, all-in-focus images. Moreover, we validated the effectiveness of the proposed system by comparing the captured images to those obtained using existing methods.

Accurate measurement of virtual image distance for near-eye displays based on auto-focusing.

Virtual reality (VR) and augmented reality (AR) are able to project virtual images to human eyes at a certain depth distance. This virtual image distance can be adjusted by controlling the diopter of the near-eye display. However, it is difficult to measure accurately and continuously since this virtual image distance spans a large range. In this work, we propose a method to accurately determine the virtual image distance of commercial VR/AR equipment. The measurement apparatus is built and calibrated to validate the feasibility. The focal distance of the focus-tunable lens can be automatically adjusted via a step motor by cooperating with the image sharpness analyzing program. Compared with other proposed methods, ours provides an effective means to achieve high accuracy, a wide and continuous testing range, and automatic evaluation of virtual image distance for compact near-eye displays.

Factors associated with overwork among pediatricians at Japanese hospitals.

BACKGROUND: Given the global health issue of doctors working excessive hours, working practices for doctors in Japan are currently undergoing reform. We aimed to ascertain the actual situation of excessive working hours among pediatricians and factors influencing these conditions in Japan. METHODS: Pediatricians employed at hospitals throughout Japan completed a questionnaire regarding their current working situation, including the time spent at the hospital and whether their working environment had improved since 2018, when the reform of doctors' working practices began. Multiple logistic regression analysis was performed to identify background factors associated with excessive working hours. RESULTS: Questionnaires were sent to 848 Japanese hospitals that submitted insurance reimbursement claims for pediatric inpatient treatment. Valid responses were received from 1,539 pediatricians at 416 hospitals (49% response rate). Of these pediatricians, 51.7% spent ≥60 h/week at their hospital, 14.4% spent ≥80 h/week, and 47.4% worked nights at least four times a month. Compared with 2018, 8.8% and 35.4% responded that their working environment had greatly or somewhat improved, respectively. Working for ≤60 h/week was considered appropriate by 81.9% of pediatricians. Background factors associated with spending ≥80 h/week at the hospital were male sex, age <30 years, lack of children, specialty of pediatric cardiology, annual income exceeding ¥16 million, employment at a private university hospital, and employment at a hospital with a comparatively large number of pediatricians. CONCLUSIONS: This study clarified the background factors and the actual situation of the long working hours among pediatricians working in Japanese hospitals.

Overwork among resident physicians: national questionnaire survey results.

BACKGROUND: Residents experience the longest working hours among physicians. Thus, it would be beneficial to perform a nationwide survey in Japan on residents' long work hours and the background factors promoting upper limits on working hours of Japanese residents. The aim of this study was to study or assess the state of physicians' excessive work hours and its background factors using a questionnaire survey. METHODS: The survey was sent to 924 hospitals. The physicians' general attributes, work hours and conditions, and employers' foundational entities were explored. Multiple logistic regression analysis was performed to elucidate the background factors for long work hours. RESULTS: Of the 4306 resident physicians who responded, 67% had ≥ 60 in-hospital hours/week and 27% had ≥ 80 h/week; 51% were on-call ≥ four times/month. Many of them hoped for increased remuneration. Additionally, female (reference: male, OR: 0.65, 95% CI: 0.55-0.76), 35-40 years old (reference: 25-30 years old, OR: 1.83, 95% CI: 1.32-2.54), childlessness (reference: child, OR: 1.41, 95% CI: 1.12-1.75), surgical specialization (reference: internal medicine, OR: 2.51, 95% CI: 1.96-3.23), neurosurgical specialization (reference: internal medicine, OR: 4.38, 95% CI: 2.92-6.59) and hospitals with 200-400 physicians (reference: <100 physicians, OR: 1.82, 95% CI: 1.12-2.96) exhibited significant correlations with ≥ 80 in-hospital hours/week. CONCLUSION: Understanding the factors that increase the likelihood of residents working very long hours could aid in making targeted changes to address the specific concerns. Moreover, reducing working hours to a reasonable limit can improve resident physicians' health and the quality of care they provide in their community.

Wide viewing angle with a downsized system in projection-type integral photography by using curved mirrors.

To obtain a large viewing angle in conventional projection-type integral photography frameworks, multiple projectors need to be arranged at a particular angle to a lens array. Hence, the systems require a large space. This paper proposes a system that achieves a large viewing angle in a space-saving manner by using curved mirrors that face each other. To this end, a projector is placed directly behind a lens array, and curved mirrors are installed to surround the rays from the projector. The incident angle toward the lens array increases after there are multiple reflections between the mirrors, which increases the viewing angle. In addition, it is not necessary to install the projector at an angle to the lens array, which results in a space-saving system. With the proposed method, a viewing angle of ±60 deg can be achieved.

Robust optical axis control of monocular active gazing based on pan-tilt mirrors for high dynamic targets.

The real-time and stability performance are both crucial for the active vision system (AVS) to gaze the high dynamic targets (HDTs). This study focused on the robust optical axis control mechanism of monocular AVS based on pan-tilt mirrors. We proposed an adaptive self-window to accommodate the HDTs within the region of interest. The minimum-envelope-ellipse and unscented-Kalman-filter methods were proposed to compensate and predict the angle of optical axis when the HDTs were blocked. The static and dynamic compensation error rates were less than 1.46% and 2.71%, prediction error rate was less than 13.88%, improving the gazing stability while ensuring real-time performance.

Extended depth-of-field projection method using a high-speed projector with a synchronized oscillating variable-focus lens.

For a projector-based virtual reality (VR) or augmented reality (AR) display, a large depth of field and a high-speed image refresh rate are important keys to improve the projector's performance. Here, we propose a solution that extends the depth of field of the projection using a variable-focus lens and a high-speed projector as well as a control method that synchronizes oscillation of the variable-focus lens with the high-speed projector. The experiment confirms that the proposed system can project the well-focused and dynamically changeable contents on six different planes. Its projection range varies from 0.3 m to 1.5 m, and the refresh rate is 166.7 Hz.

Patients' impressions of after-hours house-call services during the COVID-19 pandemic in Japan: a questionnaire-based observational study.

BACKGROUND: Access to healthcare has been strongly affected by the coronavirus disease 2019 (COVID-19) pandemic, which has raised concerns about the increased risk of delays in receiving medical care. This study aimed to assess the patients' impressions of after-hour house-call (AHHC) medical services during the COVID-19 pandemic using a patient questionnaire. METHODS: This was a cross-sectional observational study of anonymized medical record data and internet-based questionnaires from patients who used AHHC medical services from April 2020 to January 2021. We summarized the patients' impressions of AHHC medical services during the COVID-19 pandemic stratified by patient characteristics. The questions of the questionnaire were as follows: (i) Did you use the AHHC medical services because you suspected you had COVID-19 infection? (ii) Do you feel that the use of AHHC medical services has helped prevent transmission of COVID-19? (iii) What action would you have taken in the absence of AHHC medical services? RESULTS: A total of 1802 patients responded to the questionnaire (response rate: 11.3%). First, 700 (40.8%) of the responders indicated that they had used AHHC medical services because of suspicion of COVID-19. Second, most responders (88.8%) felt that AHHC medical services prevented transmission of COVID-19. Third, 774 (43.0%) of the responders considered that they would have visited an emergency department or called an ambulance if AHHC medical services had not been used. Furthermore, 411 (22.8%) of the responders indicated that they would remain at home or wait until working hours if AHHC medical services were not available despite having a condition that required emergency attention. CONCLUSIONS: AHHC medical services may be one of the strategies for those who refrain from seeking healthcare services, thus reducing the risk of delayed hospital visits during emergencies. Furthermore, AHHC medical services may also contribute to preventing transmission of COVID-19 by avoiding contact with other patients in the hospital.

Sub-Frame Evaluation of Frame Synchronization for Camera Network Using Linearly Oscillating Light Spot.

Precisely evaluating the frame synchronization of the camera network is often required for accurate data fusion from multiple visual information. This paper presents a novel method to estimate the synchronization accuracy by using inherent visual information of linearly oscillating light spot captured in the camera images instead of using luminescence information or depending on external measurement instrument. The suggested method is compared to the conventional evaluation method to prove the feasibility. Our experiment result implies that the estimation accuracy of the frame synchronization can be achieved in sub-millisecond order.

Development of a Real-Time Human-Robot Collaborative System Based on 1 kHz Visual Feedback Control and Its Application to a Peg-in-Hole Task.

In this research, we focused on Human-Robot collaboration. There were two goals: (1) to develop and evaluate a real-time Human-Robot collaborative system, and (2) to achieve concrete tasks such as collaborative peg-in-hole using the developed system. We proposed an algorithm for visual sensing and robot hand control to perform collaborative motion, and we analyzed the stability of the collaborative system and a so-called collaborative error caused by image processing and latency. We achieved collaborative motion using this developed system and evaluated the collaborative error on the basis of the analysis results. Moreover, we aimed to realize a collaborative peg-in-hole task that required a system with high speed and high accuracy. To achieve this goal, we analyzed the conditions required for performing the collaborative peg-in-hole task from the viewpoints of geometric, force and posture conditions. Finally, in this work, we show the experimental results and data of the collaborative peg-in-hole task, and we examine the effectiveness of our collaborative system.

BIFNOM: Binary-Coded Features on Normal Maps.

We propose a novel method for detecting features on normal maps and describing binary features, called BIFNOM, which is three-dimensionally rotation invariant and detects and matches interest points at high speed regardless of whether a target is textured or textureless and rigid or non-rigid. Conventional methods of detecting features on normal maps can also be applied to textureless targets, in contrast with features on luminance images; however, they cannot deal with three-dimensional rotation between each pair of corresponding interest points due to the definition of orientation, or they have difficulty achieving fast detection and matching due to a heavy-weight descriptor. We addressed these issues by introducing a three dimensional local coordinate system and converting a normal vector to a binary code, and achieved more than 750fps real-time feature detection and matching. Furthermore, we present an extended descriptor and criteria for real-time tracking, and evaluate the performance with both simulation and actual system.

Visualization Method for the Cell-Level Vesicle Transport Using Optical Flow and a Diverging Colormap.

Elucidation of cell-level transport mediated by vesicles within a living cell provides key information regarding viral infection processes and also drug delivery mechanisms. Although the single-particle tracking method has enabled clear analysis of individual vesicle trajectories, information regarding the entire cell-level intracellular transport is hardly obtainable, due to the difficulty in collecting a large dataset with current methods. In this paper, we propose a visualization method of vesicle transport using optical flow, based on geometric cell center estimation and vector analysis, for measuring the trafficking directions. As a quantitative visualization method for determining the intracellular transport status, the proposed method is expected to be universally exploited in various biomedical cell image analyses.

Optimal Material Search for Infrared Markers under Non-Heating and Heating Conditions.

Research on optimal markers for infrared imaging and differences in their characteristics in the presence of heat sources has not yet been performed. This study investigates optimal material combinations for developing an accurate and detachable infrared marker for multiple conditions in the medium wave infrared (MWIR) region. Based on four requirements, 11 material combinations are systematically evaluated. Consequently, the optimal marker differs in relation to the presence of specular reflection components. Metal-insulator markers are suitable under non-heating and hot-air heating conditions without reflection components, although a printed marker made of copier paper is captured more clearly than metal-insulator markers during heating, using an optical radiation heating source with reflection components. Our findings can be applied in structural health monitoring and multi-modal projection involving heat sources.

Pre- and post-home visit behaviors after using after-hours house call (AHHC) medical services: a questionnaire-based survey in Tokyo, Japan.

BACKGROUND: After-hours house call (AHHC) medical services have been implemented in Japan to reduce ambulance use, as well as overcrowding at the emergency department (ED). Examining the pre-and post-home visit behaviors of those using AHHC medical services will provide insights into the usefulness of these services and help develop strategies to reduce ED visits and ambulance use further. METHODS: This questionnaire-based study used data from anonymized medical records and internet-based questionnaires completed by patients who used AHHC medical services in Tokyo, Japan, between January 1 and December 31, 2019. The questionnaire comprised two questions: (1) What action would the patient have taken in the absence of AHHC services and (2) what action was taken within 3 days following the use of the AHHC services. In addition, following home consultations, AHHC doctors classified the patient's illness severity as mild (treatable with over-the-counter medications), moderate (requires hospital or clinic visit), or severe (requires ambulance transportation). RESULTS: Of the 15,787 patients who used AHHC medical services during the study period, 2128 completed the questionnaire (13.5% response rate). Individuals aged ≤15 years and 16-64 years were the most common users of AHHC services (≤15 years, 71.4%; 16-64 years, 26.8%). Before using the AHHC service, 46.4% of the total respondents reported that they would have visited an ED had AHHC services not been available (≤15 years, 47.8%; 16-64 years, 42.8%; ≥65 years, 43.6%). The proportion of patients originally planning to call an ambulance was higher among those in the older age groups (≤15 years, 1.1%; 16-64 years, 6.0%; ≥65 years, 20.5%). After using the AHHC services, most patients (68.1%) did not visit a hospital within 3 days; however, the proportion of patients who visited an ED and called an ambulance within 3 days increased with the severity of illness. CONCLUSIONS: Increasing AHHC medical services awareness among older adults and patients assessed as having severe illnesses regularly availing of AHHC services may help reduce ED visits and ambulance use.

Factors associated with undertriage in patients classified by the need to visit a hospital by telephone triage: a retrospective cohort study.

BACKGROUND: Prehospital telephone triage stratifies patients into five categories, "need immediate hospital visit by ambulance," "need to visit a hospital within 1 hour," "need to visit a hospital within 6 hours," "need to visit a hospital within 24 hours," and "do not need a hospital visit" in Japan. However, studies on whether present and past histories cause undertriage are limited in patients triaged as need an early hospital visit. We investigated factors associated with undertriage by comparing patient assessed to be appropriately triaged with those assessed undertriaged. METHODS: We included all patients classified by telephone triage as need to visit a hospital within 1 h and 6 h who used a single after-hours house call (AHHC) medical service in Tokyo, Japan, between November 1, 2019, and November 31, 2020. After home consultation, AHHC doctors classified patients as grade 1 (treatable with over-the-counter medications), 2 (requires hospital or clinic visit), or 3 (requires ambulance transportation). Patients classified as grade 2 and 3 were defined as appropriately triaged and undertriaged, respectively. RESULTS: We identified 10,742 eligible patients triaged as need to visit a hospital within 1 h and 6 h, including 10,479 (97.6%) appropriately triaged and 263 (2.4%) undertriaged patients. Multivariable logistic regression analyses revealed patients aged 16-64, 65-74, and ≥ 75 years (adjusted odds ratio [OR], 2.40 [95% confidence interval {CI} 1.71-3.36], 8.57 [95% CI 4.83-15.2], and 14.9 [95% CI 9.65-23.0], respectively; reference patients aged < 15 years); those with diabetes mellitus (2.31 [95% CI 1.25-4.26]); those with dementia (2.32 [95% CI 1.05-5.10]); and those with a history of cerebral infarction (1.98 [95% CI 1.01-3.87]) as more likely to be undertriaged. CONCLUSIONS: We found that older adults and patients with diabetes mellitus, dementia, or a history of cerebral infarction were at risk of undertriage in patients triaged as need to visit a hospital within 1 h and 6 h, but further studies are needed to validate these findings.

Changes in the proportion and severity of patients with fever or common cold symptoms utilizing an after-hours house call medical service during the COVID-19 pandemic in Tokyo, Japan: a retrospective cohort study.

BACKGROUND: Trends in the characteristics and disease severity of patients using an after-hours house call (AHHC) medical service changed during the coronavirus disease (COVID-19) pandemic. However, there have been no reports on this issue since the start of the COVID-19 pandemic. This study aimed to investigate patients' tendencies to utilize an AHHC medical service for fever or common cold symptoms during the COVID-19 pandemic. METHODS: This retrospective cohort study compared the characteristics and disease severity of patients with fever or common cold symptoms utilizing an AHHC medical service offered by a single large company between the control period (December 1, 2018 to April 30, 2019) and the COVID-19 pandemic exposure period (December 1, 2019 to April 30, 2020). We also assessed the proportion of these patients in relation to all patients calling the service for any reason. RESULTS: During the control and COVID-19 pandemic exposure periods, a total of 6462 and 10,003 patients consulted the AHHC medical service, respectively. Of these, 5335 (82.6%) and 7423 (74.2%) patients had fever and common cold symptoms, respectively, during the control and COVID-19 pandemic exposure periods (P < 0.001). The corresponding median (interquartile range) ages were 8 (3-11) and 10 (4-33) years, respectively. The distribution of disease severity differed between the groups. The proportions of patients with mild, moderate, and severe illness were 71.1, 28.7, and 0.2% in the control period and 42.3, 56.7, and 0.9% in the COVID-19 pandemic exposure period, respectively (P < 0.001). CONCLUSIONS: During the COVID-19 pandemic, the proportion of patients with fever or common cold symptoms was lower than that in the control period, but disease severity was significantly higher.

Time changes in the geographical distribution of physicians and factors associated with starting rural practice in Japan.

PURPOSE: The geographical maldistribution of physicians is an important issue for health policy. This study aimed to evaluate recent trends in Japan and identify the factors associated with starting a rural practice. METHODS: A longitudinal study was conducted using secondary analysis of national census data. The number of physicians in each region was described in 1996, 2006, and 2016 and, for two cohorts, 1996 to 2006 and 2006 to 2016; a logistic regression analysis was used to identify factors related to starting a rural practice after 10 years. FINDINGS: Between 1996 and 2016, the number of physicians in rural areas increased by 4%. Results of the logistic regression analysis showed that, in both cohorts, the factor with the highest odds ratio for starting a rural practice after 10 years was initial academic hospital experience. Other factors showing positive correlations were additional hospital practice and being qualified and over 30 years old, whereas female sex and aged at least 40 years had negative correlations. CONCLUSIONS: From 1996 to 2016, despite the increase in the total number of physicians, geographical maldistribution increased. Some findings support the policy that some physicians should work in rural areas in return for scholarships.

Real-Time Traffic Light Detection with Frequency Patterns Using a High-speed Camera.

LEDs are widely employed as traffic lights. Because most LED traffic lights are driven by alternative power, they blink at high frequencies, even at twice their frequencies. We propose a method to detect a traffic light from images captured by a high-speed camera that can recognize a blinking traffic light. This technique is robust under various illuminations because it can detect traffic lights by extracting information from the blinking pixels at a specific frequency. The method is composed of six modules, which includes a band-pass filter and a Kalman filter. All the modules run simultaneously to achieve real-time processing and can run at 500 fps for images with a resolution of 800 × 600. This technique was verified on an original dataset captured by a high-speed camera under different illumination conditions such as a sunset or night scene. The recall and accuracy justify the generalization of the proposed detection system. In particular, it can detect traffic lights with a different appearance without tuning parameters and without datasets having to be learned.