摘要:

AbstractNuclear theory predicts that secondary minima develop in the nuclear potential energy surface of some nuclei as they are stretched or elongated. Some minima are deep enough to support quasistationary states. The states are metastable because the decay is inhibited by the required shape change. Detection of these metastable states and their associated rotational bands allows us to investigate nuclei at large deformations and test existing theoretical predictions. The identification of these difficult‐to‐locate structures will permit the detailed study of nuclei at extraordinarily high deformation, providing new insights into nuclear structure. We discuss the application of model‐based image processing techniques to detect and enhance the nuclear rotational bands in noisy experimental measurements. The aim of the experiment is to identify the shape isomer by detecting the presence of the associated rotational band pattern. Unfortunately, the band signal is only ≈︁1% or less of the amplitude of similar disturbance signals due to the nuclear states of normal deformation; thus the signal‐to‐noise ratio is quite poor. Thus it is necessary to investigate image processing techniques to detect and extract the predicted band pattern. Using a model‐based approach, that is, characterizing a particular band by a simple mathematical model and incorporating it into an image processing scheme, we show that we are able to solve the band pattern detection and enhancement problems from both synthesized and measured ex

ISSN:0899-9457    

DOI:10.1002/ima.1850030102

出版商:John Wiley&Sons, Inc.    

年代:1991

数据来源: WILEY

摘要:

AbstractA laser radar sensor provides 3D information about a scene by using range measurements. A Hough transform approach is used to extract geometric information from these range values in order to identify planar building walls. Features of the extracted walls, such as their size, orientation, and distance relative to other walls, can be used to match against a reference list of walls with this spatial information. Target location can then be estimated by solving simultaneous equations using matched planar surfaces. Experimental results of computed target locations are shown to be satisfactory.

ISSN:0899-9457    

DOI:10.1002/ima.1850030103

出版商:John Wiley&Sons, Inc.    

年代:1991

数据来源: WILEY

摘要:

AbstractAn inverse scattering theory is used to design optical waveguides capable of transmitting spatial images without degradation. The propagation characteristics ofNmodes each carrying a pixel of the image are specified by a transverse rational reflection coefficient. The Gel'fand‐Levitan‐Marchenko inverse scattering theory is used to obtain the unique solution of the permittivity profile of the waveguide from the reflection coeffic

ISSN:0899-9457    

DOI:10.1002/ima.1850030104

出版商:John Wiley&Sons, Inc.    

年代:1991

数据来源: WILEY

摘要:

AbstractAttenuation imaging has the promise to become a measurement technique for ultrasound imaging systems more sophisticated than those we currently possess; however, the difficulties in using the presently available methods tend to limit this potential for the non‐specialist. In our recent work, we have investigated the attenuation imaging problem, and have had some success with an alternative technique, namely, attenuation‐velocity product imaging. In certain cases this can be an acceptable substitute for purely attenuation imaging, particularly for the soft tissues encountered in some diagnostic medical situations where the acoustic velocities of the various layers are all of approximately the same value. This article discusses our technique in detail, beginning with fundamental considerations. We make no unreasonable assumptions about the object under study, and yet are able to show the uniqueness of the solution and also deal effectively with the problem of multiple reflections. The data encountered in this experimental configuration have several intriguing properties, which allow us to draw some conclusions about acoustic imaging in gene

ISSN:0899-9457    

DOI:10.1002/ima.1850030105

出版商:John Wiley&Sons, Inc.    

年代:1991

数据来源: WILEY

摘要:

AbstractThe problem of recovering the true underlying scene from a noisy image is considered. Several methods are compared empirically by applying them to magnetic resonance (MR) images. It turns out that a simple method, the Gaussian window filter, gives good results. This method requires only “instantaneous” process

ISSN:0899-9457    

DOI:10.1002/ima.1850030106

出版商:John Wiley&Sons, Inc.    

年代:1991

数据来源: WILEY

摘要:

AbstractSeismic reflection profiles contain not only primary reflections but also sequences of reverberating events called multiple reflections. Field recordings are presented that demonstrate various types of multiple reflections that commonly occur on marine seismic profiles. Their presence is enhanced by the fact that submarine soils often exhibit so little dip that they approximate horizontal layers. If the recording geometry is such that the seismic wave fronts propagate in a direction perpendicular to the layers, individual wavelets within sequences can be identified on the basis of their record times. Having been identified, the amplitudes and phases of these wavelets can be compared to provide information concerning the material within which they reverberate. The comparison does not rely on knowledge of the source. An example of estimating sea‐floor density by comparing water‐layer multiples is given. Observations in waters that have received industrial effluent indicate that such comparisons could be useful when investigating accumulations of waste mater

ISSN:0899-9457    

DOI:10.1002/ima.1850030107

出版商:John Wiley&Sons, Inc.    

年代:1991

数据来源: WILEY

摘要:

AbstractThis article presents solid modeling of space station structures in a multiprocessing environment such as the Cray YMP 8/864. A space station is modeled as a collection of space trusses. Elements of trusses are created concurrently using constructive solid geometry. Concurrent solid modeling of large structures can be integrated with parallel algorithms for optimization of such structures in order to fully automate their computer‐aided design in a multiprocessing environmen

ISSN:0899-9457    

DOI:10.1002/ima.1850030108

出版商:John Wiley&Sons, Inc.    

年代:1991

数据来源: WILEY

ISSN:0899-9457    

DOI:10.1002/ima.1850030109

出版商:John Wiley&Sons, Inc.    

年代:1991

数据来源: WILEY

ISSN:0899-9457    

DOI:10.1002/ima.1850030101

出版商:John Wiley&Sons, Inc.    

年代:1991

数据来源: WILEY