The plant hormones auxin and abscisic acid may at first sight appear to be a conflicting pair of plant regulators. Abscisic acid content increases during stress and protects plant water status. The ...content of free auxin in the developing xylem of poplar declines during stress, while auxin conjugates increase. This indicates that specific down-regulation of a signal transduction chain is important in plant adaptation to stress. Diminished auxin content may be a factor that adapts growth and wood development of poplar during adverse environmental conditions. To allow integration of environmental signals, abscisic acid and auxin must interact. Data are accumulating that abscisic acid-auxin cross-talk exists in plants. However, knowledge of the role of plant hormones in the response of trees to stress is scarce. Our data show that differences in the localisation of ABA synthesis exist between the annual, herbaceous plant Arabidopsis and the perennial woody species, poplar.
For conventional SfM pipeline, image matching is enduring limitation when considering the time efficiency. In the last few years, to speed up image matching procedure, many image retrieval works were ...proposed to fast find overlapping image pairs, e.g., bag-of-word that clusters hand-crafted local features in a hierarchical way for efficient similar image retrieval, or learning-based global features (such as, VGG or ResNet) are used to represent image in a global compact manner. However, there are rarely benchmarks with referenced overlapping information to: first, evaluate the retrieval performance; second, fine tune deep-learning models along the direction that is more capable to deal with overlapping image pairs.In this work, based on traditional photogrammetric procedures, relevant photogrammetric information is obtained including image orientation parameters, 3D mesh model and etc., we then generate a benchmark for determining Overlapping Images - BeDOI, in which referenced pairwise overlapping relationships are estimated via rigorous photogrammetric geometry. To extend the generality, in total, BeDOI contains 13667 images which are basically UAV and close-range images of various scene categories, e.g., urban cities, campus, village, historical relics, green land, buildings and etc. Lastly, to demonstrate the efficacy of the proposed BeDOI, several image retrieval methods are tested and the experimental results are reported as a competition challenge.
In the last years, vision-based systems have flourished at an unprecedented pace, fuelled by developments in hardware components (higher resolution and higher sensitivity imaging sensors, smaller and ...smarter micro controllers, just to name a few), as well as in software or processing techniques, with AI (Artificial Intelligence) leading to a landmark revolution. Several disciplines have fostered and benefited from these advances, but, unfortunately, not always in a coordinated and cooperative way.When it comes to image-based sensing techniques, photogrammetry, computer vision and robotic vision have many contact points and overlapping areas. Yet, as for people of different cultures and languages, communicating among the three different communities can be very harsh and disorienting - especially for beginners and non-specialists.Driven by a strong educational and inclusive ambition, the LightCam project is funded by the ISPRS Education and Capacity Building Initiatives 2020 (ECB). The project’s ambition is to act as an interpreter and ease the dialog among the three actors, i.e. photogrammetry, computer vision and robotics. Two intermediation tools will be developed to serve this aim: (i) a dictionary of concepts, terminology and algorithms, in the form of a knowledge base website, and (ii) a code repository, where pieces of code for the conversion between different formulations implemented in available software solutions will be shared.
A reliable and sensitive analysis of sulfites in food is essential in food monitoring. However, the established methods exhibit deficiencies in the very low concentration ranges (below 10
mg/L
SO
2
...), especially with more complex food matrices. With a focus on these challenges, an HPLC method with immobilized enzyme reactor (HPLC–IMER) for the analysis of sulfites in food was optimized and compared to a standard method. A modulated sample preparation procedure and the use of a novel sulfite oxidase from
Arabidopsis thaliana were explored to make the method applicable for most food samples. The plant sulfite oxidase turned out to be superior to the commercially available animal sulfite oxidase in terms of detection limit (0.01
mg/L
SO
2
), linear range (0.04–20
mg/L
SO
2
) and stability. In a small scale comparison within our laboratory, as well as in a standardized proficiency testing, the HPLC–IMER was compared to an established distillative method. The enzyme-based method is not only more sensitive and specific, it also yields higher sulfite recoveries in almost all samples while exhibiting better statistic method parameters.
Salinity represents an increasing environmental problem in managed ecosystems. Populus spp. is widely used for wood production by short-rotation forestry in fertilized plantations and can be grown on ...saline soil. Because N fertilization plays an important role in salt tolerance, we analysed Grey poplar (Populus tremula x alba, syn. Populus canescens) grown with either 1 mM nitrate or ammonium subjected to moderate 75 mM NaCl. The impact of N nutrition on amelioration of salt tolerance was analysed on different levels of N metabolism such as N uptake, assimilation and N (total N, proteins and amino compounds) accumulation. Na concentration increased in all tissues over time of salt exposure. The N nutrition-dependent effects of salt exposure were more intensive in roots than in leaves. Application of salt reduced root increment as well as stem height increase and, at the same time, increased the concentration of total amino compounds more intensively in roots of ammonium-fed plants. In leaves, salt treatment increased concentrations of total N more intensively in nitrate-fed plants and concentrations of amino compounds independently of N nutrition. The major changes in N metabolism of Grey poplar exposed to moderate salt concentrations were detected in the significant increase of amino acid concentrations. The present results indicate that N metabolism of Grey poplar exposed to salt performed better when the plants were fed with nitrate instead of ammonium as sole N source. Therefore, nitrate fertilization of poplar plantations grown on saline soil should be preferred.
Multi-view stereo has been shown to be a viable tool for the creation of realistic 3D city models. Nevertheless, it still states significant challenges since it results in dense, but noisy and ...incomplete point clouds when applied to aerial images. 3D city modelling usually requires a different representation of the 3D scene than these point clouds. This paper applies a fully-automatic pipeline to generate a simplified mesh from a given dense point cloud. The mesh provides a certain level of abstraction as it only consists of relatively large planar and textured surfaces. Thus, it is possible to remove noise, outlier, as well as clutter, while maintaining a high level of accuracy.
MODERN METHODS OF BUNDLE ADJUSTMENT ON THE GPU Hänsch, R.; Drude, I.; Hellwich, O.
ISPRS annals of the photogrammetry, remote sensing and spatial information sciences,
06/2016, Letnik:
III-3
Journal Article
Recenzirano
Odprti dostop
The task to compute 3D reconstructions from large amounts of data has become an active field of research within the last years. Based on an initial estimate provided by structure from motion, bundle ...adjustment seeks to find a solution that is optimal for all cameras and 3D points. The corresponding nonlinear optimization problem is usually solved by the Levenberg-Marquardt algorithm combined with conjugate gradient descent. While many adaptations and extensions to the classical bundle adjustment approach have been proposed, only few works consider the acceleration potentials of GPU systems. This paper elaborates the possibilities of time and space savings when fitting the implementation strategy to the terms and requirements of realizing a bundler on heterogeneous CPUGPU systems. Instead of focusing on the standard approach of Levenberg-Marquardt optimization alone, nonlinear conjugate gradient descent and alternating resection-intersection are studied as two alternatives. The experiments show that in particular alternating resection-intersection reaches low error rates very fast, but converges to larger error rates than Levenberg-Marquardt. PBA, as one of the current state-of-the-art bundlers, converges slower in 50 % of the test cases and needs 1.5-2 times more memory than the Levenberg- Marquardt implementation.
The automatic classification of land cover types from hyperspectral images is a challenging problem due to (among others) the large amount of spectral bands and their high spatial and spectral ...correlation. The extraction of meaningful features, that enables a subsequent classifier to distinguish between different land cover classes, is often limited to a subset of all available data dimensions which is found by band selection techniques or other methods of dimensionality reduction. This work applies Projection-Based Random Forests to hyperspectral images, which not only overcome the need of an explicit feature extraction, but also provide mechanisms to automatically select spectral bands that contain original (i.e. non-redundant) as well as highly meaningful information for the given classification task. The proposed method is applied to four challenging hyperspectral datasets and it is shown that the effective number of spectral bands can be considerably limited without loosing too much of classification performance, e.g. a loss of 1 % accuracy if roughly 13 % of all available bands are used.
A rigorous model supported by botanical investigations has been developed to predict percolation results. Botanical investigations provide needed modeling parameters like pore size, porosity, or ...target compound distributions over the particle. After determining the desorption isotherm with maceration experiments at different solvent‐feed ratios, the model is validated with short residence time percolation experiments. With the aid of this validated model, percolation experiments with long residence times can be predicted and different process scenarios calculated. A combination of design of experiments and rigorous modeling together with standard equipment and experimental model parameter determination provides a fast and robust experimental design on the one hand and the precondition for a process parameter data‐based learning curve on the basis of rigorous modeling in the mid‐ or long‐term on the other hand.
A rigorous model supported by botanical investigations with SEM, confocal laser scanning microscopy, and Raman/IR‐spectroscopy to predict percolation results has been developed. After determining the maximum target compound content in the raw material and the desorption isotherm with maceration experiments, percolation experiments can be predicted and different process scenarios can be calculated.
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