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Now showing items 1 - 16 of 21

  • Estimation of Citrus Maturity with Florescence Spectroscopy Using Deep Learning

    Itakura, Kenta   Saito, Yoshito   Suzuki, Tetsuhito   Kondo, Naoshi   Hosoi, Fumiki  

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  • Three-Dimensional Monitoring of Plant Structural Parameters and Chlorophyll Distribution

    Itakura, Kenta   Kamakura, Itchoku   Hosoi, Fumiki  

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  • Estimation of Leaf Inclination Angle in Three-Dimensional Plant Images Obtained from Lidar

    Itakura, Kenta   Hosoi, Fumiki  

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  • Comparison between Rice Plant Traits and Color Indices Calculated from UAV Remote Sensing Images

    Shimojima, Kohei   Ogawa, Satoshi   Naito, Hiroki   Valencia, Milton Orlando   Shimizu, Yo   Hosoi, Fumiki   Uga, Yusaku   Ishitani, Manabu   Selvaraj, Michael Gomez   Omasa, Kenji  

    Remote sensing technology for monitoring plant trains has a huge potential to accelerate breeding process. In this paper, we have studied on remote sensing of using an unmanned aerial vehicle (UAV) system for plant traits phenotyping in rice. The images of rice canopy were taken by a RGB camera from the UAV at three growing stages; Vegetative (VG), Flowering (FW) and Grain filling (GF). Typical color indices (r, g, b, INT, VIG, L*, a*, b*, H) were calculated by image processing. Single regression analysis was conducted between rice plant traits (leaf area index (LAI), grain yield, above ground biomass, plant height, panicle length, grain filling rate, tiller number) and color indices. The index a* at FW and GF had close liner relationships with LAI (the coefficient of determination R-2 > 0.70) and grain yield (R-2 > 0.50). Moreover, a* and g at FW and GF showed high R-2 with plant height and grain filling rate (R-2 > 0.50). The R-2 between grain yield and color indices increased above 0.5 for about 40 of models at three growing stages by multiple regression analysis. In particular, the models of H and INT and of H and L* at VG were closely related (R-2 > 0.70). Our findings show the analysis of color images taken by UAV remote sensing is useful to assessing four rice traits; LAI, grain yield, plant height and grain filling rate at early stage, and especially more available for grain yield estimation.
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  • 3D lidar imaging for detecting and understanding plant responses and canopy structure

    Omasa, Kenji   Hosoi, Fumiki   Konishi, Atsumi  

    Understanding and diagnosing plant responses to stress will benefit greatly from three-dimensional (3D) measurement and analysis of plant properties because plant responses are strongly related to their 3D structures. Light detection and ranging (lidar) has recently emerged as a powerful tool for direct 3D measurement of plant structure. Here the use of 3D lidar imaging to estimate plant properties such as canopy height, canopy structure, carbon stock, and species is demonstrated, and plant growth and shape responses are assessed by reviewing the development of lidar systems and their applications from the leaf level to canopy remote sensing. In addition, the recent creation of accurate 3D lidar images combined with natural colour, chlorophyll fluorescence, photochemical reflectance index, and leaf temperature images is demonstrated, thereby providing information on responses of pigments, photosynthesis, transpiration, stomatal opening, and shape to environmental stresses; these data can be integrated with 3D images of the plants using computer graphics techniques. Future lidar applications that provide more accurate dynamic estimation of various plant properties should improve our understanding of plant responses to stress and of interactions between plants and their environment. Moreover, combining 3D lidar with other passive and active imaging techniques will potentially improve the accuracy of airborne and satellite remote sensing, and make it possible to analyse 3D information on ecophysiological responses and levels of various substances in agricultural and ecological applications and in observations of the global biosphere.
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  • MODIS vegetation and water indices for drought assessment in semi-arid ecosystems of Iran

    RAHIMZADEH BAJGIRAN, Parinaz   SHIMIZU, Yo   HOSOI, Fumiki   OMASA, Kenji  

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  • Estimating 3D Leaf and Stem Shape of Nursery Paprika Plants by a Novel Multi-Camera Photography System

    Zhang, Yu   Teng, Poching   Shimizu, Yo   Hosoi, Fumiki   Omasa, Kenji  

    For plant breeding and growth monitoring, accurate measurements of plant structure parameters are very crucial. We have, therefore, developed a high efficiency Multi-Camera Photography (MCP) system combining Multi-View Stereovision (MVS) with the Structure from Motion (SfM) algorithm. In this paper, we measured six variables of nursery paprika plants and investigated the accuracy of 3D models reconstructed from photos taken by four lens types at four different positions. The results demonstrated that error between the estimated and measured values was small, and the root-mean-square errors (RMSE) for leaf width/length and stem height/diameter were 1.65 mm (R-2 =3D 0.98) and 0.57 mm (R-2 =3D 0.99), respectively. The accuracies of the 3D model reconstruction of leaf and stem by a 28-mm lens at the first and third camera positions were the highest, and the number of reconstructed fine-scale 3D model shape surfaces of leaf and stem is the most. The results confirmed the practicability of our new method for the reconstruction of fine-scale plant model and accurate estimation of the plant parameters. They also displayed that our system is a good system for capturing high-resolution 3D images of nursery plants with high efficiency.
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  • High-power dye laser using steady-state amplification with chirped pulses

    Hosoi, Fumiki   Shimura, Masaru   Nabekawa, Yasuo   Kondo, Kiminori   Watanabe, Shuntaro  

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  • 3-D Modeling of Tomato Canopies Using a High-Resolution Portable Scanning Lidar for Extracting Structural Information

    Hosoi, Fumiki   Nakabayashi, Kazushige   Omasa, Kenji  

    In the present study, an attempt was made to produce a precise 3D image of a tomato canopy using a portable high-resolution scanning lidar. The tomato canopy was scanned by the lidar from three positions surrounding it. Through the scanning, the point cloud data of the canopy were obtained and they were co-registered. Then, points corresponding to leaves were extracted and converted into polygon images. From the polygon images, leaf areas were accurately estimated with a mean absolute percent error of 4.6%. Vertical profile of leaf area density (LAD) and leaf area index (LAI) could be also estimated by summing up each leaf area derived from the polygon images. Leaf inclination angle could be also estimated from the 3-D polygon image. It was shown that leaf inclination angles had different values at each part of a leaf.
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  • Detecting seasonal change of broad-leaved woody canopy leaf area density profile using 3D portable LIDAR imaging

    Hosoi, Fumiki   Omasa, Kenji  

    Seasonal change of vertical leaf area density (LAD) profiles of woody canopy broad-leaved trees (Zelkova serrata [Thunberg] Makino) was estimated using 3D portable scanning light detection and ranging (LIDAR) imaging. First, 3D point cloud data for the canopy were collected using a portable LIDAR in spring, summer, autumn and winter. For data collection, the canopy was evenly scanned by the LIDAR from three positions 10m above the ground. Next, the vertical LAD profile in each season was computed from the LIDAR data using the voxel-based canopy profiling (VCP) method. For the computation, non-photosynthetic tissues were eliminated using the LIDAR data obtained during winter. Influence of leaf inclination angle (LIA) on LAD estimation was corrected by LIA data measured by a high-resolution portable scanning LIDAR. The resultant profiles showed that LAD values tended to increase at the upper canopy from spring to summer and decrease at the middle and lower canopy from summer to autumn. Moreover, LIDAR-derived LIA distributions were compared among different seasons. LIA showed an even distribution in spring but changed to a planophile distribution in summer. In autumn, the angles in the <30 degrees class decreased and those between the 30 and 40 degrees classes increased.
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  • Estimation of Ground Surface and Accuracy Assessments of Growth Parameters for a Sweet Potato Community in Ridge Cultivation

    Teng, Poching   Ono, Eiichi   Zhang, Yu   Aono, Mitsuko   Shimizu, Yo   Hosoi, Fumiki   Omasa, Kenji  

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  • Voxel-based 3-D modeling of individual trees for estimating leaf area density using high-resolution portable scanning lidar

    Hosoi, Fumiki   Omasa, Kenji  

    A method for accurate estimation of leaf area density (LAD) and the cumulative leaf area index (LAI) profiles of small trees (Camellia sasanqua and Deutzia crenata) under different conditions was demonstrated, which used precise voxel-based tree models produced by high-resolution portable scanning lidar. In this voxel-based canopy profiling (VCP) method, data for each horizontal layer of the canopy of each tree were collected from symmetrical azimuthal measurement points around the tree using optimally inclined laser beams. The data were then converted into a voxel-based three-dimensional model that reproduced the tree precisely, including within the canopy. This precise voxel model allowed the LAD and LAI of these trees, which have extremely dense and nonrandomly distributed foliage, to be computed by direct counting of the beam-contact frequency in each layer using a point-quadrat method. Corrections for leaf inclination and nonphotosynthetic tissues reduced the. estimation error. A beam incident zenith angle near 57.5 degrees offered a good correction for leaf inclination without knowledge of the actual leaf inclination. Nonphotosynthetic tissues were removed by image-processing techniques. The best LAD estimations showed errors of 17% at the minimum horizontal layer thickness and of 0.7% at the maximum thickness. The error of the best LAI estimations was also 0.7%.
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  • Summer-season Differences in NDVI and iTVDI among Vegetation Cover Types in Lake Mashu, Hokkaido, Japan Using Landsat TM Data

    NAITO, Hiroki   RAHIMZADEH-BAJGIRAN, Parinaz   SHIMIZU, Yo   HOSOI, Fumiki   OMASA, Kenji  

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  • 3D monitoring spatio-temporal effects of herbicide on a whole plant using combined range and chlorophyll a fluorescence imaging

    Konishi, Atsumi   Eguchi, Akira   Hosoi, Fumiki  

    Spatio-temporal effects of herbicide including 3-(3,4 dichlorophenyl)-1,1-dimethylurea (DCMU) on a whole melon (Cucumis melo L.) plant were three-dimensionally monitored using combined range and chlorophyll a fluorescence imaging. The herbicide was treated to soil in a pot and the changes in chlorophyll a fluorescence images of the plant were captured over time. The time series of chlorophyll fluorescence images were combined with 3D polygon model of the whole plant taken by a high-resolution portable scanning lidar. From the produced 3D chlorophyll fluorescence model, it was observed that the increase of chlorophyll fluorescence appeared along veins of leaves and gradually expanded to mesophylls. In addition, it was found by detailed analysis of the images that the invisible herbicide injury on the mature leaves occurred earlier and more severely than on the young and old leaves. The distance from veins, whole leaf area and leaf inclination influenced the extent of the injury within the leaves. These results indicated difference in uptake of herbicide in the plant from soil depends on structural parameters of leaves and the microenvironments as well as leaf age. The findings showed that 3D monitoring using combined range and chlorophyll a fluorescence imaging can be utilised for understanding spatio-temporal changes of herbicide effects on a whole plant.
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  • 3D Confocal Laser Scanning Microscopy for the Analysis of Chlorophyll Fluorescence Parameters of Chloroplasts in Intact Leaf Tissues

    Omasa, Kenji   Konishi, Atsumi   Tamura, Hikaru   Hosoi, Fumiki  

    We analyzed the chlorophyll fluorescence parameters in a 3D cellular arrangement in vivo by using a modified Nipkow disk-type confocal laser scanning microscope (CLSM). We first defined the 3D values of (PSII) (photochemical yield of PSII) and NPQ (non-photochemical quenching) in mesophyll, epidermal and guard cell chloroplasts from the leaf surface to several tens of microns in depth. We also used this CLSM method to analyze the relationships between actinic light intensity and the chlorophyll fluorescence parameters for Boston fern and broad bean leaf specimens. As the actinic light intensity increased, the mean (PSII) values decreased and the NPQ values increased in all chloroplasts of Boston fern and broad bean leaf. These values differed with cell type and species. The Boston fern chloroplasts had lower (PSII) values than the broad bean chloroplasts, and vice versa for the NPQ values. The (PSII) values of Boston fern chloroplasts decreased in the order mesophyll, epidermal and guard cell chloroplasts. The NPQ values decreased in the order guard cell, mesophyll and epidermal chloroplasts, except at 12molm(2)s(1) actinic light, when the mesophyll value was slightly lower than that of the epidermis. The trend in the (PSII) and NPQ values of broad bean mesophyll and guard cell chloroplasts was opposite to that of Boston fern chloroplasts. As 3D CLSM can provide the (PSII) and NPQ values of each chloroplast in a 3D cellular arrangement, this method has potential for investigating differences in the functions of chloroplasts in vivo.
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  • Estimating 3D Chlorophyll Content Distribution of Trees Using an Image Fusion Method Between 2D Camera and 3D Portable Scanning Lidar

    Hosoi, Fumiki   Umeyama, Sho   Kuo, Kuangting  

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