Jun-ichi Kudoh

Image Fusion Processing for IKONOS 1-m Color Imagery

Many image fusion techniques have been developed. However, most existing fusion processes produce color distortion in 1-m fused IKONOS images due to nonsymmetrical spectral responses of IKONOS imagery. Here, we proposed a fusion process to minimize this spectral distortion in IKONOS 1-m color images. The 1-m fused image is produced from a 4-m multispectral (MS) and 1-m panchromatic (PAN) image, maintaining the relations of spectral responses between PAN and each band of the MS images. To obtain this relation, four spectral weighting parameters are added with the pixel value of each band of the original MS image. Then, each pixel value is updated using a steepest descent method to reflect the maximum spectral response on the fused image. Comparison among the proposed technique and existing processes [intensity hue saturation (IHS) image fusion, Brovey transform, principal component analysis, fast IHS image fusion] has been done. Our proposed technique has succeeded to generate 1-m fused images where spectral distortion has been reduced significantly, although some block distortions appeared at the edge of the fused images. To remove this block distortion, we also proposed a sharpening process using a wavelet transform, which removed block distortion without significant change in the color of the entire image.

A-HIGHERS-The system to produce the High spatial Resolution sea surface temperature maps of the Western North Pacific using the AVHRR/NOAA

To study on the oceanic variations in the western North Pacific, we developed a system to produce a high spatial resolution sea surface temperature (SST) map from the data obtained by the Advanced Very High Resolution Radiometer (AVHRR) aboard the National Oceanic and Atmospheric Administration (NOAA) satellites. As the system has been improved on the HIGHERS (Sakaida and Kawamura, 1996), it is called the Advanced-HIGHERS (A-HIGHERS). The A-HIGHERS has been developed on the super computer in the Tohoku University, which is favorable for handling of a large volume of data. Mainly because of improvements in the cloud detection algorithm, the A-HIGHERS can deal with the data obtained at dawn and dusk around the year, and at daytime in summer more effectively. The A-HIGHERS are used to produce SST maps spanning from (60°N, 120°E) to (20°N, 160°E) with a grid size of 0.01 degree.

Theoretical study of phase transitions in Kr and Ar clathrate hydrates from structure II to structure I under pressure.

The theory developed in our earlier papers is extended to predict dynamical and thermodynamic properties of clathrate structures by accounting for the possibility of multiple filling of cavities by guest molecules. The method is applied to the thermodynamic properties of argon and krypton hydrates, considering both structures I (sI) and II (sII), in which the small cages can be singly occupied and large cages of sII can be singly or doubly occupied. It was confirmed that the structure of the clathrate hydrate is determined by two main factors: intermolecular interaction between guest and host molecules and the configurational entropy. It is shown that for guests weakly interacting with water molecules, such as argon or krypton, the free energy of host lattices without the contribution of entropy is the main structure-determining factor for clathrate hydrates, and it is a cause of hydrate sII formation at low pressure with these guests. Explicit account of the entropy contribution in the Gibbs free energy allows one to determine the stability of hydrate phases and to estimate the line of structural transition from sII to sI in P-T plane. The structural transition between sII and sI in argon and krypton hydrates at high pressure is shown to be the consequence of increasing intermolecular interaction and the degree of occupancy of the large cavities.

Quantitative high-resolution electron microscopy of a high-Tc superconductor Tl2Ba2Cu1Oy with the imaging plate

Abstract A high-resolution electron microscope image of the high-Tc superconductor Tl2Ba2Cu1Oy was quantitatively observed by using the imaging plate. In order to quantitatively evaluate the difference between the intensity of the observed image and that of calculated images, a residual index RHREM (= Σ|Iobs − Ical |/ΣIobs) was calcu lated for 743 sampling points in the unit cell projected along the [010] direction. Although it has a rather complicated layered structure, RHREM = 0.0473 was obtained by choosing the experimental parameters and taking into account the partial occupancy of Tl atoms. Based on the analysis of the high-resolution electron microscope image of Tl2Ba2Cu1Oy, several requirements for further refinement of crystal structure analysis by quantitative high-resolution microscopy were discussed.

Thermal expansion and lattice distortion of clathrate hydrates of cubic structures I and II

Abstract Thermal expansion of clathrate hydrates of argon, krypton, and propane with cubic structure II (CS-II), methane and xenon hydrates of cubic structure I (CS-I) and empty lattices of CS-I and CS-II at zero pressure have been investigated within the framework of lattice dynamics approach in quasiharmonic approximation. For all hydrates a good agreement with experiment for lattice parameters at some fixed temperatures have been obtained. In the case of the CS-II, it is found that inclusion of sufficiently small molecules such as argon and krypton into the water framework results in effective compression of empty hydrate lattice. In the case of large propane molecules included only in the large cavities the lattice is expanded relative to the empty lattice. The thermal expansion coefficients of hydrates with large enclathrated molecules are less than for hydrates formed by small guest molecules and the smallest value of thermal expansion coefficient is obtained for the empty lattice. By comparison of the data obtained for xenon and methane hydrates of CS-I and the empty lattice of CS-I it is found that the same behavior is observed also in the case of hydrates of CS-I. The effect of lattice stretching due to guest size on the reference chemical potential between the empty lattices of CS-I and ice Ih and empty lattice of CS-II and ice Ih is calculated too.

Identification of fog with NOAA AVHRR images

The authors attempted to identify fog using image-processing data from the US National Oceanic and Atmospheric Administration (NOAA) Advanced Very High Resolution Radiometer (AVHRR). AVHRR sensors measure radiation at visible, near-infrared, and infrared wavelengths. Attention is confined to daytime data from channel 1 (CH1), channel 3 (CH3), and channel 4 (CH4) for a detection range of lambda =0.58 approximately 0.68 mu m, lambda =3.55 approximately 3.93 mu m, and lambda =10.5 approximately 11.5 mu m, respectively. The authors have analyzed by image processing the data obtained from CH1, CH3, and CH4 by forming two- and three-dimensional histograms and enhancing them in color. >

Two dimensional Forest Fire Detection method by using NOAA AVHRR images

We have studied Forest Fire Detection method with NOAA AVHRR images. The 14 years forest fires points were accumulate in a three dimensional histogram in Far East Russia region. The combinations of channels were 1, 3 and 5. The results shows almost all the channel 3 values were saturated. So, two dimensional histogram composed on channel 1 and 5 is obtained, which provides reliability fire detection corresponding to occurrence number of the histogram. This makes some looped area in the histogram. The valuation shows that the area over 5 of the occurrence number in the histogram detected the fire for another region images without errors.

IKONOS image fusion process using steepest descent method with bi-linear interpolation

There are many image fusion processes to produce a high-resolution multispectral (MS) image from low-resolution MS and high-resolution panchromatic (PAN) images. But the most significant problems are colour distortion and fusion quality. Previously, we reported a fusion process that produced a1 m resolution IKONOS fused image with minimal spectral distortion. However, block distortion appeared at the edge of the curved sections of the fused image, which was reduced by performing the wavelet transformation as a post-process. Here, we propose an image fusion process using the steepest descent method with bi-linear interpolation, which can remove block distortion without using wavelet transformation. Bi-linear interpolation provides the proper initial values of the fused image, and then the steepest descent method produces the optimum results of the fusion process. These results achieve improvement on the spectral as well as spatial quality of a1 m resolution fused image when compared with other existing methods and remove block distortion completely.

A building of new Tohoku image database (TIDAS)

The paper describes a NOAA database for a local area of Northern Japan. From receiving the NOAA satellite data to making the final image data system, no human intervention is needed. The management system of the database involves easy maintenance, and the storage medium is optical disk. TIDAS will operate for 15 years without human intervention. The search system for the user is easy without an operation manual.<<ETX>>

Local pressure and density distribution in methane hydrate - ice Ih system

Effect of self-preservation of gas hydrates was explored over many years but there is no complete understanding how can hydrates exist in their thermodynamic instability region. We are suggesting the microscopic-level model of methane hydrate clusters immersed in ice matrix. Due to differences in thermal expansion of methane hydrate and Ice Ih the additional pressure appears in the hydrate phase and this moves it into its stability field. MD simulations were performed to find local pressure and density profiles. Results are well confirming our assumption.