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
搭建了一台手持式扫频光学相干层析(SSOCT)系统对人体皮肤进行在体成像。对该系统的性能进行了详细的分析和讨论,并与实验室内现有的传统结构谱域光学相干层析(SDOCT)系统进行了对比,其中手持式SSOCT系统的灵敏度为101 d B,SDOCT系统的...搭建了一台手持式扫频光学相干层析(SSOCT)系统对人体皮肤进行在体成像。对该系统的性能进行了详细的分析和讨论,并与实验室内现有的传统结构谱域光学相干层析(SDOCT)系统进行了对比,其中手持式SSOCT系统的灵敏度为101 d B,SDOCT系统的灵敏度为94 d B。通过一次样本模拟实验和两次人体不同位置皮肤成像的结果证明了手持式SSOCT系统的信噪比和成像深度都优于SDOCT系统。利用手持式SSOCT系统对人体胳膊内侧成像,体现了手持式SSOCT系统能够对任意位置皮肤成像的优越性。所有实验结果证明搭建的手持式SSOCT系统除了具有使用方便的优点外,还能够提供高质量的人体皮肤微观结构图像。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
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.
文摘搭建了一台手持式扫频光学相干层析(SSOCT)系统对人体皮肤进行在体成像。对该系统的性能进行了详细的分析和讨论,并与实验室内现有的传统结构谱域光学相干层析(SDOCT)系统进行了对比,其中手持式SSOCT系统的灵敏度为101 d B,SDOCT系统的灵敏度为94 d B。通过一次样本模拟实验和两次人体不同位置皮肤成像的结果证明了手持式SSOCT系统的信噪比和成像深度都优于SDOCT系统。利用手持式SSOCT系统对人体胳膊内侧成像,体现了手持式SSOCT系统能够对任意位置皮肤成像的优越性。所有实验结果证明搭建的手持式SSOCT系统除了具有使用方便的优点外,还能够提供高质量的人体皮肤微观结构图像。
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.
