摘要:

On décrit une methode de calcul numérique simple permettant de corriger la forme de la courbe de filtrage des fréquences d'espace dans un instrument d'optique. On compare cette technique à d'autres déjà existantes. On donne une application de cette technique aux problèmes de la radioastronomie pour différents types d'instruments.

ISSN:0030-3909    

DOI:10.1080/713826279

出版商:Taylor & Francis Group    

年代:1959

数据来源: Taylor

摘要:

Until recently, descriptions of peripheral colour perception have been largely qualitative. The present paper reports a quantitative determination of the colours of peripherally presented lights, in which a foveal mixture field is used for comparison. Observations were made under dark adaptation conditions by two observers. The colour changes are analysed in terms of hue and saturation. In addition, spectral sensitivity curves are derived from the colour-matching data. Some subsidiary experiments are reported which indicate effects due to light adaptation, test luminance and exposure time. The results indicate a progressive deterioration in colour perception with distance from the fovea: tending, under the conditions of the experiment, to dichromatism at 25°-30° and to monochromatism at 40°–50°. The roles of (a) rod vision, (b) the fusion of nerve pathways, and (c) the depletion of the cone population are discussed.

ISSN:0030-3909    

DOI:10.1080/713826278

出版商:Taylor & Francis Group    

年代:1959

数据来源: Taylor

摘要:

The frequency response of an optical system may be derived from photoelectric image scanning data by a comparatively simple technique. The scanning movement is used to drive a sine-cosine potentiometer, fed by the photoelectric scanning signal, and integration of the product so formed is carried out with a low-inertia motor. Sine and cosine terms are available, and the successive Fourier coefficients are obtained by an alteration of potentiometer gearing. Values obtained with the apparatus are compared with those resulting from an equivalent digital electronic computation.

ISSN:0030-3909    

DOI:10.1080/713826275

出版商:Taylor & Francis Group    

年代:1959

数据来源: Taylor

摘要:

An apparatus is described with which reflection spectra of the human fundus can be measured at the rate of 1·2 per sec. It is used to determine bleaching and regeneration characteristics of human foveal light-sensitive substances. Evidence is presented that at least two are present; products of bleaching can be detected. A cone-monochromat is shown to possess both the red- and green-sensitive pigments found in the normal fovea.

ISSN:0030-3909    

DOI:10.1080/713826277

出版商:Taylor & Francis Group    

年代:1959

数据来源: Taylor

摘要:

General formulae have been calculated for the intensity distribution in a grating spectrograph with various types of grating errors, with aperture diffraction, with proper aberrations and with amplitude filters. The calculations were based on the theory of contrast transfer for the optical image formation. This theory permits the calculation of the spectral distribution of the light falling into the entrance slit from the measured intensity distribution with the aid of the Fourier theorem. In this way, a maximum of information can be obtained. The theory can also be applied to less conventional spectrographs where the limit of resolution does not depend on the aperture diffraction in the usual way.

ISSN:0030-3909    

DOI:10.1080/713826274

出版商:Taylor & Francis Group    

年代:1959

数据来源: Taylor

摘要:

Es werden die Bezeichnungsweisen zahlreicher Arten von Interferenzfarben nach einer genetischen Systematik aufgeführt. Für die durch doppelbrechende Objekte zwischen Polarisatoren erzeugten Farben werden die Erscheinungen bei sehr dünnen Schichten (am Anfang der 1. Ordnung) genauer untersucht, sodann die Änderungen der Farberscheinungen beim Drehen des Analysators von γ = 0 bis γ = 90°. Daraus können einige praktische Anwendungen abgeleitet werden. Im letzten Abschnitt werden die Farborte fürd= 0 bei Substanzen mit Dispersion der Doppelbrechung (Brewster-Herschel-farben) berechnet und dargestellt.

ISSN:0030-3909    

DOI:10.1080/713826280

出版商:Taylor & Francis Group    

年代:1959

数据来源: Taylor

ISSN:0030-3909    

DOI:10.1080/716099854

出版商:Taylor & Francis Group    

年代:1959

数据来源: Taylor