Seisuke Fukuda

Relating polarimetric SAR image texture to the scattering entropy

In our previous paper, an extension of the polarimetric product model to explain polarimetric variation of texture in high-resolution synthetic aperture radar (SAR) images has been proposed. The extended model suggests that existence of multiple scattering mechanisms provides the polarimetric texture diversity. In this paper, the polarimetric target decomposition theorem is utilized to validate the model. The entropy derived from the target decomposition is a useful sign of scattering randomness. The results of data analyses reveal that there is significant correlation between the variation of the K-distributions order parameters and the entropy value.

Simulation study of stochastic dark line features in correlated K-distributed images

Intensity fluctuation of synthetic aperture radar (SAR) images, due to speckle and texture, statistically brings series connections of dark pixels. Resolution enhancement of SAR systems can provide texture with correlation properties. In this paper, simulation studies are carried out to investigate the relation between the occurrence of the stochastic dark line features and texture correlation.

Experimental study for GNSS-R polarimetry

GNSS reflectomtry (GNSS-R) is a remote sensing methodology in which the GNSS satellites are applied for signal transmitters. In GNSS-R studies, an interference strategy is popular. The interference method uses interactions between direct signals from the GNSS satellites and reflected signals by sensing targets. This paper explains for principles and advantages in using the interference method. “The soil” is focused on as a main sensing object m this study. Features of soil consist of many parameters such as soil moisture, vegetation, surface roughness, etc. This study discusses sensing these soil parameters. Then, it is reported about the experiments by the interference method for verifying feasibility of this method. Based on the results of the experiments, future works are indicated for improving the measurement by the interference method and realizing another method which can be implemented without signal interference.

Forest Spatial Structure Enhancing Non-Gaussian Texture in Airborne L-Band Polsar Images

In this paper, results of texture analyses over coniferous forests using airborne L-band POLSAR data are shown. Interestingly, field experiments have disclosed existence of patch-like sparse areas in a forest division where low order parameters of the K-distribution are calculated in the texture analyses. In order to validate that the observed non-Gaussian texture is related to existence of the patch-like sparse forests, the two-component decomposition method is applied. It is successfully revealed that there is spotted high contribution of ground (double-bounce or direct) scattering in the highly textured forest division. Furthermore, difference of the ground contribution between polarization channels could encourage our understanding of polarimetric variation of the forest texture.

Flexible Operation System for the Microsatellite 'REIMEI' (INDEX)

INDEX (INnovative-technology Demonstration EXperiment) is a small scientific satellite which the Institute of Space and Astronautical Science, Japan Exploration Agency, ISAS/JAXA, has developed for observation of aurora’s small-scale dynamics as well as demonstration of advanced satellite technologies. The satellite was successfully launched on August 23th 2005 onboard a Russian-Ukrainian Dnepr rocket from the Baikonur Cosmodrome, and was renamed REIMEI. It is in a nearly sun-synchronous polar orbit with 600-650 km altitude. Figure 1 (a) and (b) show the overview of REIMEI: a CAD model and a photo on ground. The size of REIMEI is 72 × 62 × 62 cm and the mass is about 72 kg. The maximum capability of power supply reaches 160 W by two solar-concentrated panels with thin film reflectors and high efficiency (27 %) solar cells, which are one of the engineering missions of REIMEI. Other technologies to be tested are an integrated computer system for satellite control with a commercial RISC processor, full-functional three-axis attitude control (0.05 deg determination, 0.1 deg control), laminate-packed lithium ion batteries, variable emittance radiator (perovskite), and a miniature GPS receiver. And furthermore, flexible satellite operation using the dedicated ground station at the ISAS/JAXA Sagamihara campus is counted as an engineering mission. It is no exaggeration to say that the operation systems generally held the key to mission success of small satellites. In this paper, the REIMEI’s control scheme with the integrated computer is shortly introduced first (Section II). Then the flexible operation systems which use the integrated computing to advantage are described in Section III. Section IV gives conclusions.