摘要:

Automatic digital vertometers could be realized with the help of spatial interference fields. Two methods are described, one employing speckle patterns but requiring quite complex electronic signal processing, the other employing two-beam interference and requiring only a simple digital counter. Short measuring times can be achieved since no focusing is necessary with these procedures.

ISSN:0030-3909    

DOI:10.1080/713818976

出版商:Taylor & Francis Group    

年代:1975

数据来源: Taylor

摘要:

The interpretation of the fringe pattern formed by a double-exposed hologram of a deformed object leads first to the displacement of a point of the object surface. Further, if one desires to know the strains and the rotations at this point without numerical differentiation, the concept of the line of complete localization may be used. Associated to each point of the surface there is a locus in space where the light waves reflected by the vicinity of this point have all the same phase shift. Points of this curve may be determined by a criterion concerning the direction of the fringes and by use of a special device based upon it. Linear equations yield then directly and in general cases the sought strains and rotations. Some experimental results are given which attempt to show the applicability of this method. Further developments should permit the investigation of the constitutive equation of any non-transparent body.

ISSN:0030-3909    

DOI:10.1080/713818973

出版商:Taylor & Francis Group    

年代:1975

数据来源: Taylor

ISSN:0030-3909    

DOI:10.1080/713818968

出版商:Taylor & Francis Group    

年代:1975

数据来源: Taylor

摘要:

Difficulties associated with the use of Buchdahl's retardation coefficients in image assessment are examined. It is shown that, by a series of approximations and corresponding transformations, the set of coordinates of transmitted rays from any object point can be expressed as a circular region perpendicular to the optical axis. Furthermore, it is shown that, under these transformations, the form of the retardation expansion remains constant and only the coefficients need be altered. These changes are independent of the field angle, but depend on thef-number of the system. The coefficients thus derived are field-independent in contrast to those specified by most authors. Expressions for the coefficients under each of the transformations introduced are presented. Also a brief discussion of the convergence of the retardation expansion is presented and the results indicate that the above approximations are sound over the region of convergence of the truncated aberration expansion of order eight.

ISSN:0030-3909    

DOI:10.1080/713818969

出版商:Taylor & Francis Group    

年代:1975

数据来源: Taylor

摘要:

Une étude théorique antérieure [1] nous avait conduit à un système d'équations intégrales permettant la détermination du champ électromagnétique diffracté par l'intervalle compris entre les surfaces parfaitement réfléchissantes d'un plan et d'un dièdre d'angle droit, d'arête parallèle au plan, lorsque cet intervalle est éclairé par une onde plane polarisée parallèlement à l'arête. Le présent article a pour object la résolution numérique de ces équations intégrales et la vérification expérimentale des solutions dans le domaine des ondes visibles (λ= 0 633 micron). Les résultats obtenus pour des largeurs d'intervalle de quelques longueurs d'onde sont présentés sous forme de courbes donnant l'amplitude du champ dans l'intervalle diffractant et la diagramme de diffraction en amplitude à l'infini.

ISSN:0030-3909    

DOI:10.1080/713818974

出版商:Taylor & Francis Group    

年代:1975

数据来源: Taylor

摘要:

This paper presents the report of investigations ona prioriapodization of the pupil of a telescope operating in a turbulent medium. The criterion of apodization has been taken to be the maximization of the factor of encircled energy on a pre-specified area on the far-field plane. It has been observed that the optimum pupil function designed on the basis of a perfectly space-coherent wave being incident on the pupil has got to be modified by a small but significant amount to obtain the optimum function when a partially space-coherent wave is incident on the same. This leads to the possibility of using turbulence-corrector pupils in conjunction with the optimum pupil function designed for the coherent case to achieve an overall apodization. Numerical results are presented.

ISSN:0030-3909    

DOI:10.1080/713818975

出版商:Taylor & Francis Group    

年代:1975

数据来源: Taylor

摘要:

Les fentes d'entrée et de sortie d'un spectromètre sont remplacées par un système de multifentes fonctionnant comme grille d'entrée et de sortie. Contrairement aux spectromètres à grilles habituels, la modulation du faisceau lumineux a lieu dans une direction parallèle à la direction de dispersion. Nous étudions quelques avantages découlant de l'emploi de tels modèles.

ISSN:0030-3909    

DOI:10.1080/713818971

出版商:Taylor & Francis Group    

年代:1975

数据来源: Taylor

ISSN:0030-3909    

DOI:10.1080/713818970

出版商:Taylor & Francis Group    

年代:1975

数据来源: Taylor

ISSN:0030-3909    

DOI:10.1080/713818972

出版商:Taylor & Francis Group    

年代:1975

数据来源: Taylor