Handheld ultrasound devices are known for their portability and affordability,making them widely utilized in underdeveloped areas and community healthcare for rapid diagnosis and early screening.However,the image qual...Handheld ultrasound devices are known for their portability and affordability,making them widely utilized in underdeveloped areas and community healthcare for rapid diagnosis and early screening.However,the image quality of handheld ultrasound devices is not always satisfactory due to the limited equipment size,which hinders accurate diagnoses by doctors.At the same time,paired ultrasound images are difficult to obtain from the clinic because imaging process is complicated.Therefore,we propose a modified cycle generative adversarial network(cycleGAN) for ultrasound image enhancement from multiple organs via unpaired pre-training.We introduce an ultrasound image pre-training method that does not require paired images,alleviating the requirement for large-scale paired datasets.We also propose an enhanced block with different structures in the pre-training and fine-tuning phases,which can help achieve the goals of different training phases.To improve the robustness of the model,we add Gaussian noise to the training images as data augmentation.Our approach is effective in obtaining the best quantitative evaluation results using a small number of parameters and less training costs to improve the quality of handheld ultrasound devices.展开更多
Considering that it is difficult to monitor the measurement system and amend the test parameters on the scene in shock wave overpressure measurement and it is inconvenient to operate and carry traditional PC in outdoo...Considering that it is difficult to monitor the measurement system and amend the test parameters on the scene in shock wave overpressure measurement and it is inconvenient to operate and carry traditional PC in outdoor experiments, a new handheld terminal for shock wave pressure measurement system based on ARM is designed, The handheld terminal, whose ap- plication program is developed by the software of Qt, can control the measurement system by Wi-Fi and perform the functions of monitoring the system state, transmitting the data by wireless and displaying waveforms. To prevent data loss, USB inter- face is designed to read the data The test results show that the designed handheld terminal has good stability and reliability in several explosion experiments.展开更多
Handover in Digital Video Broadcasting for Handhelds(DVB-H) aims to provide continuous mobile broadcasting services when a user is traveling through cell boundaries.A good handover control can improve the power effici...Handover in Digital Video Broadcasting for Handhelds(DVB-H) aims to provide continuous mobile broadcasting services when a user is traveling through cell boundaries.A good handover control can improve the power efficiency and gain much better reception quality.This letter provides a novel approach for DVB-H handover based on DVB-H/Universal Mobile Telecommunications System(UMTS) hybrid network,which moves the main handover function from the terminals to the networks,so that it reduces the operation complexity of the terminals and increases the power saving.When the terminal can not receive the DVB-H signal in the transmission shadow areas or because of some other reasons,the UMTS networks may offer the same service to users to make the service continuous.As the UMTS networks have the topology of the DVB-H networks,by communicating with the terminals,the UMTS networks can help the terminals to predict the handover,and avoid unnecessary handover.展开更多
A quantitative survey of rice planthoppers in paddy fields is important to assess the population density and make forecasting decisions. Manual rice planthopper survey methods in paddy fields are time-consuming, fatig...A quantitative survey of rice planthoppers in paddy fields is important to assess the population density and make forecasting decisions. Manual rice planthopper survey methods in paddy fields are time-consuming, fatiguing and tedious. This paper describes a handheld device for easily capturing planthopper images on rice stems and an automatic method for counting rice planthoppers based on image processing. The handheld device consists of a digital camera with WiFi, a smartphone and an extrendable pole. The surveyor can use the smartphone to control the camera, which is fixed on the front of the pole by WiFi, and to photograph planthoppers on rice stems. For the counting of planthoppers on rice stems, we adopt three layers of detection that involve the following：（a） the first layer of detection is an AdaBoost classifier based on Haar features;（b） the second layer of detection is a support vector machine（SVM） classifier based on histogram of oriented gradient（HOG） features;（c） the third layer of detection is the threshold judgment of the three features. We use this method to detect and count whiteback planthoppers（Sogatella furcifera） on rice plant images and achieve an 85.2% detection rate and a 9.6% false detection rate. The method is easy, rapid and accurate for the assessment of the population density of rice planthoppers in paddy fields.展开更多
Objective To estimate the prevalence of unknown atrial fibrillation(AF)in the elderly population of the Veneto Region,Italy.Methods 1820 patients aged≥65 years with no history of AF and not anticoagulated were enroll...Objective To estimate the prevalence of unknown atrial fibrillation(AF)in the elderly population of the Veneto Region,Italy.Methods 1820 patients aged≥65 years with no history of AF and not anticoagulated were enrolled in primary-care settings.They underwent an opportunistic electrocardiogram screening with a handheld device(My Diagnostick)designed to specifically detect AF.The electrocardiogram recordings were reviewed by the researchers,who confirmed the presence of AF.Results The device detected an arrhythmia in 143 patients,which was confirmed as AF in 101/143(70.6%),with an overall prevalence of AF of 5.5%(101/1820).Prevalence of unknown AF resulted in 3.6%in patients aged 65–74 years,and 7.5%in patients age 75 or older,and increased according to CHA2 DS2-VASc score:3.5%in patients with a score of 1 or 2,5.6%in patients with a score of 3,7.0%in patients with a score of 4,and 7.2%in patients with a score≥5.The detection rate was significantly higher in patients with mild symptoms compared to asymptomatic counterparts(24.1%vs.4.0%,P<0.0001).At multivariate analysis,congestive heart failure and age≥75 years-old were independent predictors for screen-detected AF.Conclusions An opportunistic screening with handheld device revealed an unexpectedly high prevalence of unknown AF in elderly patients with mild symptoms.Prevalence increased with age and CHA2DS2-VASc score.展开更多
AIM: To explore the performance in diabetic retinopathy(DR) screening of artificial intelligence(AI) system by evaluating the image quality of a handheld Optomed Aurora fundus camera in comparison to traditional table...AIM: To explore the performance in diabetic retinopathy(DR) screening of artificial intelligence(AI) system by evaluating the image quality of a handheld Optomed Aurora fundus camera in comparison to traditional tabletop fundus cameras and the diagnostic accuracy of DR of the two modalities. METHODS: Overall, 630 eyes were included from three centers and screened by a handheld camera(Aurora, Optomed, Oulu, Finland) and a table-top camera. Image quality was graded by three masked and experienced ophthalmologists. The diagnostic accuracy of the handheld camera and AI system was evaluated in assessing DR lesions and referable DR.RESULTS: Under nonmydriasis status, the handheld fundus camera had better image quality in centration, clarity, and visible range(1.47, 1.48, and 1.40) than conventional tabletop cameras(1.30, 1.28, and 1.18;P<0.001). Detection of retinal hemorrhage, hard exudation,and macular edema were comparable between the two modalities, in principle, with the area under the curve of the handheld fundus camera slightly lower. The sensitivity and specificity for the detection of referable DR with the handheld camera were 82.1%(95%CI: 72.1%-92.2%) and 97.4%(95%CI: 95.4%-99.5%), respectively. The performance of AI detection of DR using the Phoebus Algorithm was satisfactory;however, Phoebus showed a high sensitivity(88.2%, 95%CI: 79.4%-97.1%) and low specificity(40.7%, 95%CI: 34.1%-47.2%) when detecting referable DR.CONCLUSION: The handheld Aurora fundus camera combined with autonomous AI system is well-suited in DR screening without mydriasis because of its high sensitivity of DR detection as well as its image quality, but its specificity needs to be improved with better modeling of the data. Use of this new system is safe and effective in the detection of referable DR in real world practice.展开更多
This objective of the study was to develop a model for the determination of N deficiency in cherry trees using a combination of visible near infrared methods and spectro-radiometric measurement.In our experimental des...This objective of the study was to develop a model for the determination of N deficiency in cherry trees using a combination of visible near infrared methods and spectro-radiometric measurement.In our experimental design,cherry seedlings were grown under various N deficiency conditions in nutrient-controlled containers.The reflectance values of plant leaves were measured using a spectro-radiometer.Plant leaves samples were simultaneously collected.Their nutrient contents were determined in the laboratory.Afterwards,we performed a statistical comparison of the reflectance values.Sample analysis results established the significant wavelengths.Moreover,we received accurate regression models for predicting N deficiency in cherry leaves that were grown in nutrient solutions.Next,we verified the model validity by measuring the reflectance of the leaves collected from cherry orchards at various locations using a spectroradiometer.Nutrient deficiencies were calculated using the developed model,and then,the predicted and measured data were compared to evaluate model validity.From these results,we determined the wavelengths that yielded the most accurate results for N prediction,selected from the blue and green regions of the spectrum.We established that for N prediction in cherry trees,the simplest model can be created using 560and 570nm wavelengths.However,the evaluated model can be applicable only under certain conditions.We concluded that in order to develop aprediction method with sufficient application capacity,as well as the ability to assess nutritional and physiological characteristics,the ecology condition of the plant should be properly considered based on the model.展开更多
BACKGROUND:The use of ultrasound(US)within healthcare has inspired the development of new US technology.There have been few studies comparing the use of handheld US to standard US for medical education.This research a...BACKGROUND:The use of ultrasound(US)within healthcare has inspired the development of new US technology.There have been few studies comparing the use of handheld US to standard US for medical education.This research aims to determine whether a handheld US device can provide a comparable primary learning experience to that of a standard US machine.METHODS:Over two days of instruction,participants were taught and evaluated on core US fundamentals.The standard group received instruction on standard US machines,while the handheld group received instruction on handheld US devices.Participants completed a qualitative survey regarding their experience.Six hundred and four images were obtained and graded by two emergency medicine physicians.RESULTS:A total of 119 Swiss medical students were enrolled in our study.There was no statistically significant difference in the US assessment measurements,except for faster endpoint septal separation(EPSS)vascular setup time in the handheld group(P=0.001).There was no statistically significant difference in participants’perceived difficulty of US learning(P=0.198),comfort level(P=0.188),or self-estimated capability to perform US in the future(P=0.442).There was no statistically significant difference in the percentage of correctly obtained images(P=0.211)or images that were clinically useful(P=0.256).The median quality score of images obtained by the standard group was eight compared to seven in handheld group(P<0.01).CONCLUSION:Our data suggest a handheld US machine can perform as well as a standard US machine as an educational tool despite sacrifices in image quality.展开更多
Sustainable forest management heavily relies on the accurate estimation of tree parameters.Among others,the diameter at breast height(DBH) is important for extracting the volume and mass of an individual tree.For syst...Sustainable forest management heavily relies on the accurate estimation of tree parameters.Among others,the diameter at breast height(DBH) is important for extracting the volume and mass of an individual tree.For systematically estimating the volume of entire plots,airborne laser scanning(ALS) data are used.The estimation model is frequently calibrated using manual DBH measurements or static terrestrial laser scans(STLS) of sample plots.Although reliable,this method is time-consuming,which greatly hampers its use.Here,a handheld mobile terrestrial laser scanning(HMTLS) was demonstrated to be a useful alternative technique to precisely and efficiently calculate DBH.Different data acquisition techniques were applied at a sample plot,then the resulting parameters were comparatively analysed.The calculated DBH values were comparable to the manual measurements for HMTLS,STLS,and ALS data sets.Given the comparability of the extracted parameters,with a reduced point density of HTMLS compared to STLS data,and the reasonable increase of performance,with a reduction of acquisition time with a factor of5 compared to conventional STLS techniques and a factor of3 compared to manual measurements,HMTLS is considered a useful alternative technique.展开更多
This work focuses on a brief discussion of new concepts of using smartphone sensors for 3D painting in virtual or augmented reality. Motivation of this research comes from the idea of using different types of sensors ...This work focuses on a brief discussion of new concepts of using smartphone sensors for 3D painting in virtual or augmented reality. Motivation of this research comes from the idea of using different types of sensors which exist in our smartphones such as accelerometer, gyroscope, magnetometer etc. to track the position for painting in virtual reality, like Google Tilt Brush, but cost effectively. Research studies till date on estimating position and localization and tracking have been thoroughly reviewed to find the appropriate algorithm which will provide accurate result with minimum drift error. Sensor fusion, Inertial Measurement Unit (IMU), MEMS inertial sensor, Kalman filter based global translational localization systems are studied. It is observed, prevailing approaches consist issues such as stability, random bias drift, noisy acceleration output, position estimation error, robustness or accuracy, cost effectiveness etc. Moreover, issues with motions that do not follow laws of physics, bandwidth, restrictive nature of assumptions, scale optimization for large space are noticed as well. Advantages of such smartphone sensor based position estimation approaches include, less memory demand, very fast operation, making them well suited for real time problems and embedded systems. Being independent of the size of the system, they can work effectively for high dimensional systems as well. Through study of these approaches it is observed, extended Kalman filter gives the highest accuracy with reduced requirement of excess hardware during tracking. It renders better and faster result when used in accelerometer sensor. With the aid of various software, error accuracy can be increased further as well.展开更多
This paper presents a handheld 3D vision-based scanner for small objects by using Kinect. It is different from the previous color-glove-based approaches which require segmenting the target object. First, we eliminate ...This paper presents a handheld 3D vision-based scanner for small objects by using Kinect. It is different from the previous color-glove-based approaches which require segmenting the target object. First, we eliminate the noises and the outliers caused by holding hands. Second, we apply Kinect-fusion algorithm and truncated signed distance function （TSDF） to represent 3D surfaces. Third, we propose a modified integration strategy to eliminate the hand effect. Fourth, we take advantage of the parallel computation of GPUs for real-time operation. The major contributions of this paper are （1） the registration precision is improved, （2） the oflline amendment and loop closure operation are not required, and （3） concave 3D object reconstruction is feasible.展开更多
One of the emerging technologies is wireless handheld technology. Implication of these devices is enormous for business community and healthcare domain is not an exception to this phenomena. This research paper provid...One of the emerging technologies is wireless handheld technology. Implication of these devices is enormous for business community and healthcare domain is not an exception to this phenomena. This research paper provides some useful findings about the use of PDA＇s in the healthcare environment through actual usage of PDA in the healthcare ward. A qualitative and quantitative approach is adopted to explore these phenomena due to the exploratory nature of the research. Findings of this study identify some of the motivators and issues associated with the wireless handheld technology in healthcare environment. Furthermore, it is also found that these wireless handheld devices can help to improve the quality of care through better decision making processes. This study is limited to only one sate of Australian and further research is needed to see the implication of the findings to wider community and other domains in the Australian environment.展开更多
<b>Introduction:</b> Ultrasound facilitates neuraxial puncture in obese parturients. Unfortunately, the widespread adoption of neuraxial ultrasound may be limited by the lack of technical expertise or the ...<b>Introduction:</b> Ultrasound facilitates neuraxial puncture in obese parturients. Unfortunately, the widespread adoption of neuraxial ultrasound may be limited by the lack of technical expertise or the limited availability of the equipment. A wireless portable ultrasound device (Accuro, Rivanna Medical, Charlottesville, VA) with automated pattern recognition software (SpineNav3DTM technology) has been introduced to obtain the automated real-time identification of interspaces and epidural depth. The primary objective of this study was to assess the accuracy of the SpineNav3DTM ultrasound technology (Accuro) in estimating the epidural space depth compared to the standard ultrasound examination in pregnant obese patients. The secondary aim was to compare the ultrasound measurements with the measured needle depth during epidural and spinal insertion. <b>Methods:</b> The study was conducted at S Gerardo Hospital, Monza, Italy from March 2021 to April 2021. Obese laboring women requesting epidural analgesia or undergoing elective cesarean delivery under spinal anesthesia were recruited. All the subjects had their lumbar area scanned for the measurements of the depth of the epidural space by the SpineNav3DTM ultrasound technology and by the standard US and then both compared with the needle insertion depth in a double-blind fashion. <b>Results:</b> Forty-eight women were enrolled in the study. There was agreement (±0.25 cm) between the epidural depth (in cm) measured with the Accuro, versus the standard ultrasound. There was a significant difference between the mean depth of epidural space s measured by Accuro or Standard US and needle insertion depth (P < 0.001). <b>Conclusions:</b> The handheld ultrasound system with 3D spine navigation technology can automatically identify and measure the epidural depth with the same accuracy as the standard ultrasounds in obese pregnant women.展开更多
Acute and chronic wounds affect millions of people around the world,imposing a growing financial burden on patients and hospitals.Despite the application of current wound management strategies,the physiological healin...Acute and chronic wounds affect millions of people around the world,imposing a growing financial burden on patients and hospitals.Despite the application of current wound management strategies,the physiological healing process is disrupted in many cases,resulting in impaired wound healing.Therefore,more efficient and easy-to-use treatment modalities are needed.In this study,we demonstrate the benefit of in vivo printed,growth factor-eluting adhesive scaffolds for the treatment of full-thickness wounds in a porcine model.A custom-made handheld printer is implemented to finely print gelatin-methacryloyl(GelMA)hydrogel containing vascular endothelial growth factor(VEGF)into the wounds.In vitro and in vivo results show that the in situ GelMA crosslinking induces a strong scaffold adhesion and enables printing on curved surfaces of wet tissues,without the need for any sutures.The scaffold is further shown to offer a sustained release of VEGF,enhancing the migration of endothelial cells in vitro.Histological analyses demonstrate that the administration of the VEGF-eluting GelMA scaffolds that remain adherent to the wound bed significantly improves the quality of healing in porcine wounds.The introduced in vivo printing strategy for wound healing applications is translational and convenient to use in any place,such as an operating room,and does not require expensive bioprinters or imaging modalities.展开更多
The need for visual landscape assessment in large-scale projects for the evaluation of the effects of a particular project on the surrounding landscape has grown in recent years. Augmented reality （AR） has been cons...The need for visual landscape assessment in large-scale projects for the evaluation of the effects of a particular project on the surrounding landscape has grown in recent years. Augmented reality （AR） has been considered for use as a landscape simulation system in which a landscape assessment object created by 3D models is included in the present surroundings. With the use of this system, the time and the cost needed to perform a 3DCG modeling of present surroundings, which is a major issue in virtual reality, are drastically reduced. This research presents the development of a 3D maporiented handheld AR system that achieves geometric consistency using a 3D map to obtain position data instead of GPS, which has tow position information accuracy, particularly in urban areas. The new system also features a gyroscope sensor to obtain posture data and a video camera to capture live video of the present surroundings. All these components are mounted in a smartphone and can be used for urban landscape assessment. Registration accuracy is evaluated to simulate an urban landscape from a short- to a long-range scale. The latter involves a distance of approximately 2000 m. The developed AR system enables users to simulate a Landscape from multiple and longdistance viewpoints simultaneously and to walk around the viewpoint fields using only a smartphone. This result is the tolerance level of Landscape assessment. In conclusion, the proposed method is evaluated as feasible and effective.展开更多
Handheld optical sensors recently have been introduced to the agricultural market.These handheld sensors are able to provide operators with Normalized Difference Vegetative Index(NDVI)data when cloud cover prevents ac...Handheld optical sensors recently have been introduced to the agricultural market.These handheld sensors are able to provide operators with Normalized Difference Vegetative Index(NDVI)data when cloud cover prevents acquisition of satellite or aerial images.This research addressed the sensitivity of the GreenSeeker handheld optical sensor to changes in orientation and height above a ryegrass canopy.Planter boxes were oriented both parallel and perpendicular to the light beam from the sensor head and heights of 30.5 cm(12”),61.0 cm(24”),91.5 cm(36”),122 cm(48”)and 152 cm(60”)were tested.Results indicated that the sensor was highly sensitive(P<0.0001)to both height above canopy and orientation of the sensor relative to the target.Operators should follow manufacturer’s recommendations on operating height range of 81-122 cm and orient the sensor head in-line with the target to obtain maximum signal response.展开更多
Remote sensing satellites are playing very important roles in diverse earth observation fields.However,long revisit period,high cost and dense cloud cover have been the main limitations of satellite remote sensing for...Remote sensing satellites are playing very important roles in diverse earth observation fields.However,long revisit period,high cost and dense cloud cover have been the main limitations of satellite remote sensing for a long time.This paper introduces the novel volunteered passenger aircraft remote sensing(VPARS)concept,which can partly overcome these problems.By obtaining aerial imaging data from passengers using a portable smartphone on a passenger aircraft,it has various advantages including low cost,high revisit,dense coverage,and partial anti-cloud,which can well complement conventional remote sensing data.This paper examines the concept of VPARS and give general data processing framework of VPARS.Several cases were given to validate this processing approach.Two preliminary applications on land cover classification and economic activity monitoring validate the applicability of the VPARS data.Furthermore,we examine the issues about data maintenance,potential applications,limitations and challenges.We conclude the VPARS can benefit both scientific and industrial communities who rely on remote sensing data.展开更多
Traffic signs often convey critical information to drivers. To ensure visibility in nighttime or low light conditions, traffic signs must be in compliance with the minimum retrore- flectivity standards outlined by the...Traffic signs often convey critical information to drivers. To ensure visibility in nighttime or low light conditions, traffic signs must be in compliance with the minimum retrore- flectivity standards outlined by the manual on uniform traffic control devices （MUTCD）. Among all of the assessment methods （visual nighttime inspection, retroreflectivity measurement） and management methods （expected life, blanket replacement, and control signs） outlined in the MUTCD, expected sign life has been the most selected by agencies for maintaining compliance. In current literature, little research exists with regard to schedule sign replacement, focusing rather on the current favorite predictor, sign age. However, after collecting data on 1683 in-service traffic signs across the state of Utah, this study primarily concluded that not only sign age, but other contributing factors affect sign retroreflective performance. Aiming to determine the effects of various damage forms on sign retroreflectivity, statistical methods, including regression models, chi-square test, t- test, and odds ratio were employed to analyze traffic sign data. At the conclusion, the strong association between damage and retroreflectivity compliance of traffic signs was evident. In addition, to identify more critical damage forms, the effects of various forms on traffic sign retroreflectivity were compared. These conclusions provide insight to inform transportation agencies in the development of sign management plans and schedule sign replacement.展开更多
文摘Handheld ultrasound devices are known for their portability and affordability,making them widely utilized in underdeveloped areas and community healthcare for rapid diagnosis and early screening.However,the image quality of handheld ultrasound devices is not always satisfactory due to the limited equipment size,which hinders accurate diagnoses by doctors.At the same time,paired ultrasound images are difficult to obtain from the clinic because imaging process is complicated.Therefore,we propose a modified cycle generative adversarial network(cycleGAN) for ultrasound image enhancement from multiple organs via unpaired pre-training.We introduce an ultrasound image pre-training method that does not require paired images,alleviating the requirement for large-scale paired datasets.We also propose an enhanced block with different structures in the pre-training and fine-tuning phases,which can help achieve the goals of different training phases.To improve the robustness of the model,we add Gaussian noise to the training images as data augmentation.Our approach is effective in obtaining the best quantitative evaluation results using a small number of parameters and less training costs to improve the quality of handheld ultrasound devices.
基金The 11th Postgraduate Technology Innovation Project of North University of China(No.20141147)
文摘Considering that it is difficult to monitor the measurement system and amend the test parameters on the scene in shock wave overpressure measurement and it is inconvenient to operate and carry traditional PC in outdoor experiments, a new handheld terminal for shock wave pressure measurement system based on ARM is designed, The handheld terminal, whose ap- plication program is developed by the software of Qt, can control the measurement system by Wi-Fi and perform the functions of monitoring the system state, transmitting the data by wireless and displaying waveforms. To prevent data loss, USB inter- face is designed to read the data The test results show that the designed handheld terminal has good stability and reliability in several explosion experiments.
基金the National Science Fund for Distinguished Young Scholars (No.60525110)the National 973 Program (No.2007CB307100, No.2007CB307103)+1 种基金the Program for New Century Excellent Talents in University (No. NCET-04-0111)the Development Fund Project for Electronic and Information Industry (Mobile Service and Application System Based on 3G)
文摘Handover in Digital Video Broadcasting for Handhelds(DVB-H) aims to provide continuous mobile broadcasting services when a user is traveling through cell boundaries.A good handover control can improve the power efficiency and gain much better reception quality.This letter provides a novel approach for DVB-H handover based on DVB-H/Universal Mobile Telecommunications System(UMTS) hybrid network,which moves the main handover function from the terminals to the networks,so that it reduces the operation complexity of the terminals and increases the power saving.When the terminal can not receive the DVB-H signal in the transmission shadow areas or because of some other reasons,the UMTS networks may offer the same service to users to make the service continuous.As the UMTS networks have the topology of the DVB-H networks,by communicating with the terminals,the UMTS networks can help the terminals to predict the handover,and avoid unnecessary handover.
基金the National Natural Science Foundation of China (31071678)the National High Technology Research and Development Program of China (863 Program, 2013AA102402)Zhejiang Provincial Natural Science Foundation of China (LY13C140009)
文摘A quantitative survey of rice planthoppers in paddy fields is important to assess the population density and make forecasting decisions. Manual rice planthopper survey methods in paddy fields are time-consuming, fatiguing and tedious. This paper describes a handheld device for easily capturing planthopper images on rice stems and an automatic method for counting rice planthoppers based on image processing. The handheld device consists of a digital camera with WiFi, a smartphone and an extrendable pole. The surveyor can use the smartphone to control the camera, which is fixed on the front of the pole by WiFi, and to photograph planthoppers on rice stems. For the counting of planthoppers on rice stems, we adopt three layers of detection that involve the following：（a） the first layer of detection is an AdaBoost classifier based on Haar features;（b） the second layer of detection is a support vector machine（SVM） classifier based on histogram of oriented gradient（HOG） features;（c） the third layer of detection is the threshold judgment of the three features. We use this method to detect and count whiteback planthoppers（Sogatella furcifera） on rice plant images and achieve an 85.2% detection rate and a 9.6% false detection rate. The method is easy, rapid and accurate for the assessment of the population density of rice planthoppers in paddy fields.
文摘Objective To estimate the prevalence of unknown atrial fibrillation(AF)in the elderly population of the Veneto Region,Italy.Methods 1820 patients aged≥65 years with no history of AF and not anticoagulated were enrolled in primary-care settings.They underwent an opportunistic electrocardiogram screening with a handheld device(My Diagnostick)designed to specifically detect AF.The electrocardiogram recordings were reviewed by the researchers,who confirmed the presence of AF.Results The device detected an arrhythmia in 143 patients,which was confirmed as AF in 101/143(70.6%),with an overall prevalence of AF of 5.5%(101/1820).Prevalence of unknown AF resulted in 3.6%in patients aged 65–74 years,and 7.5%in patients age 75 or older,and increased according to CHA2 DS2-VASc score:3.5%in patients with a score of 1 or 2,5.6%in patients with a score of 3,7.0%in patients with a score of 4,and 7.2%in patients with a score≥5.The detection rate was significantly higher in patients with mild symptoms compared to asymptomatic counterparts(24.1%vs.4.0%,P<0.0001).At multivariate analysis,congestive heart failure and age≥75 years-old were independent predictors for screen-detected AF.Conclusions An opportunistic screening with handheld device revealed an unexpectedly high prevalence of unknown AF in elderly patients with mild symptoms.Prevalence increased with age and CHA2DS2-VASc score.
基金Supported by the National Natural Science Foundation of China(No.81970845)European Union’s Horizon 2020 research and innovation programme under grant agreement(No.778089)。
文摘AIM: To explore the performance in diabetic retinopathy(DR) screening of artificial intelligence(AI) system by evaluating the image quality of a handheld Optomed Aurora fundus camera in comparison to traditional tabletop fundus cameras and the diagnostic accuracy of DR of the two modalities. METHODS: Overall, 630 eyes were included from three centers and screened by a handheld camera(Aurora, Optomed, Oulu, Finland) and a table-top camera. Image quality was graded by three masked and experienced ophthalmologists. The diagnostic accuracy of the handheld camera and AI system was evaluated in assessing DR lesions and referable DR.RESULTS: Under nonmydriasis status, the handheld fundus camera had better image quality in centration, clarity, and visible range(1.47, 1.48, and 1.40) than conventional tabletop cameras(1.30, 1.28, and 1.18;P<0.001). Detection of retinal hemorrhage, hard exudation,and macular edema were comparable between the two modalities, in principle, with the area under the curve of the handheld fundus camera slightly lower. The sensitivity and specificity for the detection of referable DR with the handheld camera were 82.1%(95%CI: 72.1%-92.2%) and 97.4%(95%CI: 95.4%-99.5%), respectively. The performance of AI detection of DR using the Phoebus Algorithm was satisfactory;however, Phoebus showed a high sensitivity(88.2%, 95%CI: 79.4%-97.1%) and low specificity(40.7%, 95%CI: 34.1%-47.2%) when detecting referable DR.CONCLUSION: The handheld Aurora fundus camera combined with autonomous AI system is well-suited in DR screening without mydriasis because of its high sensitivity of DR detection as well as its image quality, but its specificity needs to be improved with better modeling of the data. Use of this new system is safe and effective in the detection of referable DR in real world practice.
基金The Scientific and Technical Research Council of Turkey,Agriculture,Forestry&Veterinary Research Grant Committee Project No TOVAG 109O376
文摘This objective of the study was to develop a model for the determination of N deficiency in cherry trees using a combination of visible near infrared methods and spectro-radiometric measurement.In our experimental design,cherry seedlings were grown under various N deficiency conditions in nutrient-controlled containers.The reflectance values of plant leaves were measured using a spectro-radiometer.Plant leaves samples were simultaneously collected.Their nutrient contents were determined in the laboratory.Afterwards,we performed a statistical comparison of the reflectance values.Sample analysis results established the significant wavelengths.Moreover,we received accurate regression models for predicting N deficiency in cherry leaves that were grown in nutrient solutions.Next,we verified the model validity by measuring the reflectance of the leaves collected from cherry orchards at various locations using a spectroradiometer.Nutrient deficiencies were calculated using the developed model,and then,the predicted and measured data were compared to evaluate model validity.From these results,we determined the wavelengths that yielded the most accurate results for N prediction,selected from the blue and green regions of the spectrum.We established that for N prediction in cherry trees,the simplest model can be created using 560and 570nm wavelengths.However,the evaluated model can be applicable only under certain conditions.We concluded that in order to develop aprediction method with sufficient application capacity,as well as the ability to assess nutritional and physiological characteristics,the ecology condition of the plant should be properly considered based on the model.
文摘BACKGROUND:The use of ultrasound(US)within healthcare has inspired the development of new US technology.There have been few studies comparing the use of handheld US to standard US for medical education.This research aims to determine whether a handheld US device can provide a comparable primary learning experience to that of a standard US machine.METHODS:Over two days of instruction,participants were taught and evaluated on core US fundamentals.The standard group received instruction on standard US machines,while the handheld group received instruction on handheld US devices.Participants completed a qualitative survey regarding their experience.Six hundred and four images were obtained and graded by two emergency medicine physicians.RESULTS:A total of 119 Swiss medical students were enrolled in our study.There was no statistically significant difference in the US assessment measurements,except for faster endpoint septal separation(EPSS)vascular setup time in the handheld group(P=0.001).There was no statistically significant difference in participants’perceived difficulty of US learning(P=0.198),comfort level(P=0.188),or self-estimated capability to perform US in the future(P=0.442).There was no statistically significant difference in the percentage of correctly obtained images(P=0.211)or images that were clinically useful(P=0.256).The median quality score of images obtained by the standard group was eight compared to seven in handheld group(P<0.01).CONCLUSION:Our data suggest a handheld US machine can perform as well as a standard US machine as an educational tool despite sacrifices in image quality.
基金funded by University College GhentGhent University。
文摘Sustainable forest management heavily relies on the accurate estimation of tree parameters.Among others,the diameter at breast height(DBH) is important for extracting the volume and mass of an individual tree.For systematically estimating the volume of entire plots,airborne laser scanning(ALS) data are used.The estimation model is frequently calibrated using manual DBH measurements or static terrestrial laser scans(STLS) of sample plots.Although reliable,this method is time-consuming,which greatly hampers its use.Here,a handheld mobile terrestrial laser scanning(HMTLS) was demonstrated to be a useful alternative technique to precisely and efficiently calculate DBH.Different data acquisition techniques were applied at a sample plot,then the resulting parameters were comparatively analysed.The calculated DBH values were comparable to the manual measurements for HMTLS,STLS,and ALS data sets.Given the comparability of the extracted parameters,with a reduced point density of HTMLS compared to STLS data,and the reasonable increase of performance,with a reduction of acquisition time with a factor of5 compared to conventional STLS techniques and a factor of3 compared to manual measurements,HMTLS is considered a useful alternative technique.
文摘This work focuses on a brief discussion of new concepts of using smartphone sensors for 3D painting in virtual or augmented reality. Motivation of this research comes from the idea of using different types of sensors which exist in our smartphones such as accelerometer, gyroscope, magnetometer etc. to track the position for painting in virtual reality, like Google Tilt Brush, but cost effectively. Research studies till date on estimating position and localization and tracking have been thoroughly reviewed to find the appropriate algorithm which will provide accurate result with minimum drift error. Sensor fusion, Inertial Measurement Unit (IMU), MEMS inertial sensor, Kalman filter based global translational localization systems are studied. It is observed, prevailing approaches consist issues such as stability, random bias drift, noisy acceleration output, position estimation error, robustness or accuracy, cost effectiveness etc. Moreover, issues with motions that do not follow laws of physics, bandwidth, restrictive nature of assumptions, scale optimization for large space are noticed as well. Advantages of such smartphone sensor based position estimation approaches include, less memory demand, very fast operation, making them well suited for real time problems and embedded systems. Being independent of the size of the system, they can work effectively for high dimensional systems as well. Through study of these approaches it is observed, extended Kalman filter gives the highest accuracy with reduced requirement of excess hardware during tracking. It renders better and faster result when used in accelerometer sensor. With the aid of various software, error accuracy can be increased further as well.
基金supported by the Ministry of Science and Technology of Taiwan under Grant No.MOST103-2221-E-468-006–MY1
文摘This paper presents a handheld 3D vision-based scanner for small objects by using Kinect. It is different from the previous color-glove-based approaches which require segmenting the target object. First, we eliminate the noises and the outliers caused by holding hands. Second, we apply Kinect-fusion algorithm and truncated signed distance function （TSDF） to represent 3D surfaces. Third, we propose a modified integration strategy to eliminate the hand effect. Fourth, we take advantage of the parallel computation of GPUs for real-time operation. The major contributions of this paper are （1） the registration precision is improved, （2） the oflline amendment and loop closure operation are not required, and （3） concave 3D object reconstruction is feasible.
文摘One of the emerging technologies is wireless handheld technology. Implication of these devices is enormous for business community and healthcare domain is not an exception to this phenomena. This research paper provides some useful findings about the use of PDA＇s in the healthcare environment through actual usage of PDA in the healthcare ward. A qualitative and quantitative approach is adopted to explore these phenomena due to the exploratory nature of the research. Findings of this study identify some of the motivators and issues associated with the wireless handheld technology in healthcare environment. Furthermore, it is also found that these wireless handheld devices can help to improve the quality of care through better decision making processes. This study is limited to only one sate of Australian and further research is needed to see the implication of the findings to wider community and other domains in the Australian environment.
文摘<b>Introduction:</b> Ultrasound facilitates neuraxial puncture in obese parturients. Unfortunately, the widespread adoption of neuraxial ultrasound may be limited by the lack of technical expertise or the limited availability of the equipment. A wireless portable ultrasound device (Accuro, Rivanna Medical, Charlottesville, VA) with automated pattern recognition software (SpineNav3DTM technology) has been introduced to obtain the automated real-time identification of interspaces and epidural depth. The primary objective of this study was to assess the accuracy of the SpineNav3DTM ultrasound technology (Accuro) in estimating the epidural space depth compared to the standard ultrasound examination in pregnant obese patients. The secondary aim was to compare the ultrasound measurements with the measured needle depth during epidural and spinal insertion. <b>Methods:</b> The study was conducted at S Gerardo Hospital, Monza, Italy from March 2021 to April 2021. Obese laboring women requesting epidural analgesia or undergoing elective cesarean delivery under spinal anesthesia were recruited. All the subjects had their lumbar area scanned for the measurements of the depth of the epidural space by the SpineNav3DTM ultrasound technology and by the standard US and then both compared with the needle insertion depth in a double-blind fashion. <b>Results:</b> Forty-eight women were enrolled in the study. There was agreement (±0.25 cm) between the epidural depth (in cm) measured with the Accuro, versus the standard ultrasound. There was a significant difference between the mean depth of epidural space s measured by Accuro or Standard US and needle insertion depth (P < 0.001). <b>Conclusions:</b> The handheld ultrasound system with 3D spine navigation technology can automatically identify and measure the epidural depth with the same accuracy as the standard ultrasounds in obese pregnant women.
基金The financial support from the National Institutes of Health(GM126831,AR073822)Stepping Strong Innovator Award are gratefully acknowledged.
文摘Acute and chronic wounds affect millions of people around the world,imposing a growing financial burden on patients and hospitals.Despite the application of current wound management strategies,the physiological healing process is disrupted in many cases,resulting in impaired wound healing.Therefore,more efficient and easy-to-use treatment modalities are needed.In this study,we demonstrate the benefit of in vivo printed,growth factor-eluting adhesive scaffolds for the treatment of full-thickness wounds in a porcine model.A custom-made handheld printer is implemented to finely print gelatin-methacryloyl(GelMA)hydrogel containing vascular endothelial growth factor(VEGF)into the wounds.In vitro and in vivo results show that the in situ GelMA crosslinking induces a strong scaffold adhesion and enables printing on curved surfaces of wet tissues,without the need for any sutures.The scaffold is further shown to offer a sustained release of VEGF,enhancing the migration of endothelial cells in vitro.Histological analyses demonstrate that the administration of the VEGF-eluting GelMA scaffolds that remain adherent to the wound bed significantly improves the quality of healing in porcine wounds.The introduced in vivo printing strategy for wound healing applications is translational and convenient to use in any place,such as an operating room,and does not require expensive bioprinters or imaging modalities.
文摘The need for visual landscape assessment in large-scale projects for the evaluation of the effects of a particular project on the surrounding landscape has grown in recent years. Augmented reality （AR） has been considered for use as a landscape simulation system in which a landscape assessment object created by 3D models is included in the present surroundings. With the use of this system, the time and the cost needed to perform a 3DCG modeling of present surroundings, which is a major issue in virtual reality, are drastically reduced. This research presents the development of a 3D maporiented handheld AR system that achieves geometric consistency using a 3D map to obtain position data instead of GPS, which has tow position information accuracy, particularly in urban areas. The new system also features a gyroscope sensor to obtain posture data and a video camera to capture live video of the present surroundings. All these components are mounted in a smartphone and can be used for urban landscape assessment. Registration accuracy is evaluated to simulate an urban landscape from a short- to a long-range scale. The latter involves a distance of approximately 2000 m. The developed AR system enables users to simulate a Landscape from multiple and longdistance viewpoints simultaneously and to walk around the viewpoint fields using only a smartphone. This result is the tolerance level of Landscape assessment. In conclusion, the proposed method is evaluated as feasible and effective.
文摘Handheld optical sensors recently have been introduced to the agricultural market.These handheld sensors are able to provide operators with Normalized Difference Vegetative Index(NDVI)data when cloud cover prevents acquisition of satellite or aerial images.This research addressed the sensitivity of the GreenSeeker handheld optical sensor to changes in orientation and height above a ryegrass canopy.Planter boxes were oriented both parallel and perpendicular to the light beam from the sensor head and heights of 30.5 cm(12”),61.0 cm(24”),91.5 cm(36”),122 cm(48”)and 152 cm(60”)were tested.Results indicated that the sensor was highly sensitive(P<0.0001)to both height above canopy and orientation of the sensor relative to the target.Operators should follow manufacturer’s recommendations on operating height range of 81-122 cm and orient the sensor head in-line with the target to obtain maximum signal response.
基金supported by National Natural Science Foundation of China(41974006)Shenzhen Scientific Research and Development Funding Program(KQJSCX20180328093453763,JCYJ20180305125101282,JCYJ20170412142239369)+1 种基金Open Fund of Key Laboratory of Urban Land Resources Monitoring and Simulation(KF-2018-03-004)Department of Education of Guangdong Province(2018KTSCX196).
文摘Remote sensing satellites are playing very important roles in diverse earth observation fields.However,long revisit period,high cost and dense cloud cover have been the main limitations of satellite remote sensing for a long time.This paper introduces the novel volunteered passenger aircraft remote sensing(VPARS)concept,which can partly overcome these problems.By obtaining aerial imaging data from passengers using a portable smartphone on a passenger aircraft,it has various advantages including low cost,high revisit,dense coverage,and partial anti-cloud,which can well complement conventional remote sensing data.This paper examines the concept of VPARS and give general data processing framework of VPARS.Several cases were given to validate this processing approach.Two preliminary applications on land cover classification and economic activity monitoring validate the applicability of the VPARS data.Furthermore,we examine the issues about data maintenance,potential applications,limitations and challenges.We conclude the VPARS can benefit both scientific and industrial communities who rely on remote sensing data.
文摘Traffic signs often convey critical information to drivers. To ensure visibility in nighttime or low light conditions, traffic signs must be in compliance with the minimum retrore- flectivity standards outlined by the manual on uniform traffic control devices （MUTCD）. Among all of the assessment methods （visual nighttime inspection, retroreflectivity measurement） and management methods （expected life, blanket replacement, and control signs） outlined in the MUTCD, expected sign life has been the most selected by agencies for maintaining compliance. In current literature, little research exists with regard to schedule sign replacement, focusing rather on the current favorite predictor, sign age. However, after collecting data on 1683 in-service traffic signs across the state of Utah, this study primarily concluded that not only sign age, but other contributing factors affect sign retroreflective performance. Aiming to determine the effects of various damage forms on sign retroreflectivity, statistical methods, including regression models, chi-square test, t- test, and odds ratio were employed to analyze traffic sign data. At the conclusion, the strong association between damage and retroreflectivity compliance of traffic signs was evident. In addition, to identify more critical damage forms, the effects of various forms on traffic sign retroreflectivity were compared. These conclusions provide insight to inform transportation agencies in the development of sign management plans and schedule sign replacement.
