IEEE Geoscience and Remote Sensing Letters

The first demonstration of a multispectral light detection and ranging (LiDAR) optimized for detailed structure and physiology measurements in forest ecosystems is described. The basic principle is to utilize, in a single instrument, both the capacity of multispectral sensing to measure plant physiology [through normalized difference vegetation index (NDVI) and photochemical reflectance index (PRI... View full abstract»

Earth observation satellites currently provide a large volume of images at different scales. Most of these satellites provide global coverage with a revisit time that usually depends on the instrument characteristics and performance. Typically, medium-spatial-resolution instruments provide better spectral and temporal resolutions than mapping-oriented high-spatial-resolution multispectral sensors.... View full abstract»

Thermal infrared (IR)-based particle image ve locimetry (PIV) is used to measure the evolution of velocity, turbulent kinetic energy (TKE), and the TKE dissipation rate at the water surface in the tidally influenced Snohomish River. Patterns of temperature variability in the IR imagery arise from disruption of the cool-skin layer and are used to estimate the 2-D velocity field. Comparisons of IR-b... View full abstract»

This letter presents a novel coarse-to-fine level set method for contour extraction in optical satellite images. To distinguish objects from a background, the undecimated wavelet transform is firstly adopted to extract image features, and a homogeneity metric is defined to measure the variation of the features inside and outside contours. In addition, the weight distribution ratio is proposed to a... View full abstract»

Dielectric measurements of powdered forest fire ash have been investigated and presented using the Nicholson-Ross-Weir method within a WR-90 waveguide (X-band 8-12 GHz). The dielectric measurements of five samples have been outlined and taken at a room temperature of 22.8 °C. Permittivity ε for five different species has been presented within this letter. These include Eucalypt, Brac... View full abstract»

This letter focuses on the thermal expansion component of persistent scatterer (PS) interferometry (PSI), which is a result of temperature differences in the imaged area between synthetic aperture radar (SAR) acquisitions. This letter is based on very high resolution X-band StripMap SAR data captured by the TerraSAR-X spaceborne sensor. The X-band SAR interferometric phases are highly influenced b... View full abstract»

We present an enhanced visualization algorithm for hyperspectral images (HSIs). The visualization is based on the projection onto color matching functions of the human vision system. A contrast enhancement procedure is introduced by the fusion of the gradient information of the individual HSI bands. Both visualization and enhancement are combined into a multiresolution framework using wavelets. Th... View full abstract»

The time-frequency peak filtering (TFPF) is an effective tool in random-noise attenuation and has been applied to seismic record denoising in recent years. The window length (WL) of the time-frequency distribution (TFD) is the key to the conventional TFPF technology. A fixed WL is not optimal for both the low- and high-frequency components at the same time; an adaptive WL results in serious distor... View full abstract»

In this letter, we propose a novel approach for unsupervised change detection in multitemporal optical satellite images. Unlike the traditional methods, the proposed method, called the soft-change detection, models the change detection as a transparency computation problem and assigns to each pixel a set of soft labels. In order to extract the pixel opacity, we optimize an objective function by ex... View full abstract»

The performance of the high-resolution synthetic aperture radar (SAR) with moving-target indication and imaging systems can be analyzed and evaluated by modeling the whole imaging system through a simulation. The raw-data generation in the time domain achieves a realistic simulation procedure provided that computational complexity can be tolerable. In this letter, we proposed an efficient SAR raw-... View full abstract»

Multiple-instance learning (MIL) is a learning paradigm used for learning a target concept in the presence of noise or with an uncertainty in target information including class labels. Due to the difficult situations in which hyperspectral images (HSIs) are collected, research in this area is extremely relevant and directly applicable. In the following, an MIL framework is proposed for target spec... View full abstract»

Linear discriminant analysis (LDA) has been widely applied for hyperspectral image (HSI) analysis as a popular method for feature extraction and dimensionality reduction. Linear methods such as LDA work well for unimodal Gaussian class-conditional distributions. However, when data samples between classes are nonlinearly separated in the input space, linear methods such as LDA are expected to fail.... View full abstract»

A new method for estimating the rotational motion of a noncooperative target is presented by exploiting the 2-D space-variant characteristic of inverse synthetic aperture radar imaging. With a space-time analysis technique, the position variation of every extracted scattering center in both the range and cross-range directions can be utilized for rotation estimation. This method differs substantia... View full abstract»

As the number of satelliteborne SAR systems increases, both the availability and the length of multitemporal (MT) sequences of SAR images have also increased. Reported research with MT SAR sequences suggests that they increase the classification accuracy for all applications over single-date images. The length of the MT SAR sequences reported in the literature is still quite modest: on the order o... View full abstract»

Highly repetitive global-scale remote sensing systems, such as the Special Sensor Microwave/Imager (SSM/I), provide essential tools for monitoring changes on the Earth's surface. This letter presents a time-series segmentation and classification method to identify surface changes and to estimate the duration (days) for the changes using daily SSM/I observations. The method was developed based on a... View full abstract»

Missing data in very high spatial resolution (VHR) optical imagery take origin mainly from the acquisition conditions. Their accurate reconstruction represents a great methodological challenge because of the complexity and the ill-posed nature of the problem. In this letter, we present three different solutions, with all based on the inpainting approach, which consists in reconstructing the missin... View full abstract»

Persistent scatterer interferometry using stacks of very high resolution synthetic aperture radar (SAR) data reveals that single or even patterns of scatterers representing building structures may wrongly be localized below the ground level. In this letter, a case study on a test building model is presented using 3-D SAR simulation methods in order to explain the underlying localization problem. T... View full abstract»

In this letter, we discuss the use of multicore processors in the acceleration of endmember extraction algorithms for hyperspectral image unmixing. Specifically, we develop computationally efficient versions of two popular fully automatic endmember extraction algorithms: orthogonal subspace projection and N-FINDR. Our experimental results, based on the analysis of hyperspectral data collected by t... View full abstract»

The Terrain Observation by Progressive Scans (TOPS) mode is a novel spaceborne imaging mode which can be used to obtain wide-swath coverage and overcome major drawbacks in conventional ScanSAR. An efficient full-aperture imaging approach, which takes advantage of the two-step focusing technique and the azimuth baseband scaling operation, is presented for processing the TOPS-mode synthetic aperture... View full abstract»

In ground-penetrating radar (GPR) imaging, the classic range migration (RM) algorithm can work well only when the imaging scene can be modeled as a single homogeneous medium. However, in most GPR field applications, the GPR system and objects operate in different mediums. The space between the antennas and the ground cannot be ignored electromagnetically. In this kind of circumstance, the imaging ... View full abstract»

SHARAD is a frequency-modulated (15-25 MHz) radar sounder that probes the upper few kilometers of the Martian crust and polar layered deposits. At solar zenith angles less than about 100°, the ionosphere of Mars can induce phase distortion in surface and subsurface radar echoes that substantially degrades the signal-to-noise ratio and vertical resolution of the range-compressed data. We pre... View full abstract»

This letter describes the first interferometric acquisitions and results obtained by the TerraSAR-X add-on for Digital Elevation Measurements mission. Due to the large along-track separation between the two satellites during the approaching maneuver and the Earth's rotation, useful interferometric acquisitions were only possible at high latitudes. This resulted in a crossing angle between the grou... View full abstract»