This paper introduces the use of aerial RGB digital photography to detect changes in soil structure at field level before vegetation appearance and in the early stages of crop development. Aerial digital photographs o...
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ISBN:
(纸本)0819451606
This paper introduces the use of aerial RGB digital photography to detect changes in soil structure at field level before vegetation appearance and in the early stages of crop development. Aerial digital photographs of a field trial were used as basis for soil structure mapping. images were acquired right after sowing the crop, and image-processing routines made it possible to detect and map changes in soil structure. The detected pattern could be recognized in the growth pattern of the canopy a month later. The field trial used in this work was subdivided into areas receiving different amounts of fertilizer, and the aerial digital photographs clearly showed the detected soil variations to overpower the influence of the differences in fertilization.
The Modulation Transfer Function (MTF) is a major parameter for high resolution optical remotesensing systems, indicating how spatial frequencies are transmitted and weakened by the imaging global chain. Assessing MT...
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ISBN:
(纸本)0819455172
The Modulation Transfer Function (MTF) is a major parameter for high resolution optical remotesensing systems, indicating how spatial frequencies are transmitted and weakened by the imaging global chain. Assessing MTF is thus a very important task during both the in-flight commissioning period and the routine monitoring phases. Classical in flight MTF measurement methods are based upon devoted well known patterns such as knife edge patterns. These techniques induce heavy constraints upon satellite payload programming taking into account nebulosity conditions and pattern ground maintenance. Moreover, for high MTF systems, MTF assessment proves to be difficult because the point spread function has a too reduced extension. Another solution consists in taking two images of the same scene, one in a high resolution mode and the other one in a lower resolution mode. When the resolution ratio is high enough (typically higher then 3), it is possible to simulate the lower resolution image through convolution with a filter and undersampling. The least square method consists in an iterative process, according to which the convolution filter evolves in order to minimize a least square criterion measuring the difference between the simulation and the low resolution image. Once the process has converged, taking the Fourier Transform of the convolution filter gives an estimation of the ratio between low resolution image MTF versus high resolution image MTF. This method may be successfully applied to remotesensing systems such as Quickbird, Ikonos, SPOT5 and future PLEIADES-HR to assess MTF in the multispectral mode. The goal of this paper is to present the MTF assessment method, the way it was validated through simulations and its application within SPOT5 context.
The detection of coal/shale interfaces close to the surface using ground penetrating radar (GPR) is difficult because the echo is drowned in unwanted signal components. These components are susceptible to changes in a...
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ISBN:
(纸本)0889864160
The detection of coal/shale interfaces close to the surface using ground penetrating radar (GPR) is difficult because the echo is drowned in unwanted signal components. These components are susceptible to changes in amplitude and cannot be removed well by standard pre-processing techniques. Second order correlation based methods such as matched filtering fail to locate the echo reliably under these conditions. Features that extract signal shape information based on the bispectrum can provide desirable immunity from clutter and noise. These features are investigated for this task using signals obtained from finite difference time domain simulations of a typical coal seam. It is shown that a patternrecognition approach using features derived from the bispectrum allows the detection of layer interfaces using GPR to be extended reliably to the near surface region.
Three-dimensional sensors based on Laser Radar (LADAR) technology possess vast potential for the future battlefield. This work presents an algorithm for the recognition of T62 and T72 tanks from 3D imagery. The algori...
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ISBN:
(纸本)0819455660
Three-dimensional sensors based on Laser Radar (LADAR) technology possess vast potential for the future battlefield. This work presents an algorithm for the recognition of T62 and T72 tanks from 3D imagery. The algorithm consists of several stages: a) Pre-processing of LADAR images to remove range noise and to determine ground level. b) Segmentation to extract regions that fulfill certain pre-defined conditions. c) Extraction of specific tank features from each region. d) Applying a Fuzzy Logic classifier applied to the feature vector to discriminate between T62 and T72 tanks and other targets or natural clutter. A commercial airborne LADAR sensor was used to acquire images from an area of 40 square kilometers with a measurement density of 20 pixels per square meter and a range noise of 15 cm (1 sigma). The images included more than a hundred man-made objects (tanks, armored personnel carriers, trucks, cranes) along with natural clutter (vegetation and boulders). Among the targets were 18 tanks, two of which were covered with a camouflage net. The algorithm recognized the 16 uncovered tanks with a False Alarm Rate (FAR) of 0.025 per square kilometer. This FAR value is better than the respective FAR values derived for 2D Imaging where Automatic Target recognition (ATR) techniques are applied. These results show promise for automatic recognition of various targets employing LADAR sensors.
We summarize our methods for the fusion of multisensor/spectral imagery based on concepts derived from neural models of visual processing (adaptive contrast enhancement, opponent-color contrast, multi-scale contour co...
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Frontal "depowered" air bag systems are underdesign today to be even more effective than current air bags in saving lives, while at the same time reducing the potential of causing an air bag induced serious ...
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Sea-ice motion consists of complex non-rigid motions involving continuous, piece-wise continuous and discrete particle motion. Techniques for estimating non-rigid motion of sea ice from pairs of satellite images (gene...
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This paper proposes the use of information derived from the graph of a texture image function for texture description. The graph of an image function is a rumpled surface in the three-dimensional space that appears li...
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ISBN:
(纸本)0769521282
This paper proposes the use of information derived from the graph of a texture image function for texture description. The graph of an image function is a rumpled surface in the three-dimensional space that appears like a landscape. Four novel texture feature curves are used to characterize the texture. This method is named as statistical landscape features (SLF). SLF achieves a very high correct classification rate of 94.53% on the entire Brodatz set. Besides the very good performance, another remarkable advantage of the proposed method is that it has no parameter to tune.
Although uncertainties exist in spatial knowledge discovery, they have not been paid much attention to. In the past years, the most researches of spatial knowledge discovery focused on the methods of data mining and i...
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