We analyze paddy fields in Nara basin in order to show that the pattern expand method is reasonable for quantitative analysis of an area which is a mixture of water, vegetation and soil. The pattern expand method has been developed to analyze remote sensing multispectral data such as Landsat TM data. First, the pattern expand method is applied to three suitable seasons' Landsat TM data. Next, these data are coregistered using affine transformation with several sets of control points, and the characteristics of paddy fields are studied through three seasons. Using three pattern expand coefficients, paddy fields can be recognized from other land cover types, and classified to three paddy field types. The coefficients of these paddy fields are compared through three seasons on the same parameter space. Lastly, paddy fields are extracted using three pattern expand coefficients, and the paddy field areas of six cities and towns in Nara basin are estimated. The paddy field areas from this analysis are in good agreement with those from statistical data.
Thermal infrared multispectral sensor data should be atmospherically corrected for estimating surface temperature and spectral emissivity. For land observations, a common method for it is using transmittance, path radiance and sky radiance estimated by a radiative transfer code such as MODTRAN. However, this method has the disadvantage that it requires both the atmospheric profile data simultaneously observed and the digital elevation model (DEM); if the quality of these data is low, the atmospherically corrected data is unreliable. We will, therefore, suggest a new method for estimating atmospheric correction parameters, surface temperature and spectral emissivity without the atmospheric profile data and the DEM. The proposed method is based on using pixels with high emissivity for all channels (gray pixels). The method is as follows: 1) Gray pixels are selected from a target area. 2) For gray pixels, upward radiance at surface level is estimated by an extended multi-channel (EMC) method which produces the upward brightness temperature of each channel at surface level by the linear combination of the observed brightness temperatures of all channels. 3) The transmittance and path radiance of each channel are estimated by the linear regression between the observed radiance and the estimated upward radiance at surface level. 4) The sky radiance is estimated by using transmittance and path radiance. As the results, all the atmospheric correction parameters are estimated. We have named this the gray pixel (GP) method. 5) For all pixels, the surface temperature and the spectral emissivity are estimated by one of the temperature and emissivity separation methods from atmospherically corrected radiance. 6) As an option, gray pixels are selected again with estimated emissivity, and each parameter is recalculated for improved accuracy. In the final part of the study, the effectiveness of the proposed method is evaluated using the Thermal Infrared Multispectral Scanner (TIMS) data. The traditional method, as well as the proposed one, is applied to the data, and the results of both methods are compared to each other. This evaluation demonstrates that the proposed method is feasible.
Airborne Synthetic Aperture Radar (SAR) imagery has widely been used for photogeologic interpretation because of its advantages such as all-weather imaging capability through clouds, high spatial resolution, and exaggeration effect of surface topography. Many previous papers reported that airborne SAR imagery is .especially useful to interpret lineaments, which is defined as linear surface topographic features that presumably reflect subsurface fractures including active faults. This paper investigates usefulness of the airborne SAR images to detect predefined and undefined active faults in Chubu district, Japan, and compares airborne and spaceborne SAR images for lineament interpretation. The airborne SAR images used in this study was obtained in 1981 as a part of a nationwide geothermal assessment project conducted by NEDO (New Energy Development Organization). We extracted many lineaments by visual photogeologic interpretation on the SAR images of Chubu district, where many active faults have already been recognized. The extracted lineaments were compared with the active faults described in "Maps of Active Faults in Japan". In this comparison, we found that most of predefined active faults were clearly indicated as lineaments in the SAR images. On the other hand, there are many lineaments that have not been defined as active faults and many lineaments which may make a line with defined active faults. We also made a comparison between the airborne SAR images and the JERS-1 (Japanese Earth Resources Satellite-1) SAR images. Geometric distortion due to a smaller off-nadir angle of the JERS-1 SAR is a major problem in lineament interpretation.
Many proven methods, like radar, electric resistance and magnetism, have been widely used to detect underground buried objects, as proven detection devices. An infrared radiometer (IR) has been widely used to detect an internal flaw of industrial structural components, as a remote sensing nondestructive method. And the method was remarkedly developed with aid of the thermal image method (TIM). Injecting the solar and artifical combustion radiation energy on a ground surface, the near-underground buried objects was detected by observing nonuniform and discontinuous distribution of the radiation temperature above the object by means of the IR. The IR method was used to examined experimentally to detected the buried tomb in Komochi village, Gunma prefecture, as an application study. We could observed the non-uniform distribution of the radiation temperature above the tomb, as in case of test results by the radar and electric tests.