Showing papers in "Journal of the Optical Society of America in 1955"
TL;DR: A quantitative model for an opponent-colors theory of vision is presented that is based on the CIE color mixture data for the standard observer to account for spectral brightness, saturation, and hue and some of their associated psychophysical functions in both normal and dichromatic vision.
Abstract: A quantitative model for an opponent-colors theory of vision is presented that is based on the CIE color mixture data for the standard observer. The model is used to account for spectral brightness, saturation, and hue and some of their associated psychophysical functions in both normal and dichromatic vision. Special attention is given to an account of the Bezold-Brucke hue shift, and to changes in saturation and wavelength discrimination with changes in stimulus luminance.
370 citations
TL;DR: In this article, the spectral distributions of the chromatic components were measured using an opponent-colors theory of vision, and the measured chromatic responses, together with achromatic (luminosity) functions, were used to predict the form of the spectral saturation discrimination function.
Abstract: Saturation discrimination is assumed to be dependent on the ratio of chromatic to achromatic components in the sensory response to a given wavelength. The usual methods of measurement do not, however, permit independent control of the chromatic and achromatic variables. On the basis of an opponent-colors theory of vision, a method is described for measuring directly and separately the spectral distributions of the chromatic components. A series of experiments is reported in which this method was used to obtain measures of the paired chromatic responses associated with the four primary spectral hues. Results are reported for two observers, 1° foveal test field, for an equal brightness spectrum (10 mL), and a neutral state of adaptation (10 mL). The measured chromatic responses, together with achromatic (luminosity) functions measured earlier for the same observers, are used to predict the form of the spectral saturation discrimination function.
366 citations
TL;DR: In this paper, it was shown that in the case of coherent illumination, a large class of objects corresponding to a given image can be found very easily, and that two-point resolution is impossible unless the observer has a priori an infinite amount of information about the object.
Abstract: The degrees of freedom of an image formed by any real instrument are only a finite number, while those those of the object are an infinite number. Several different objects may correspond to the same image.It is shown that in the case of coherent illumination a large class of objects corresponding to a given image can be found very easily. Two-point resolution is impossible unless the observer has a priori an infinite amount of information about the object.
298 citations
TL;DR: In this paper, the general theory of the integrating sphere as used in the measurement of total spectral reflectance is formulated as an integral equation and solved for five special cases, and two methods of measuring reflectance are considered.
Abstract: The general theory of the integrating sphere as used in the measurement of total spectral reflectance is formulated as an integral equation and solved for five special cases. Two methods of measuring reflectance are considered. In the substitution method, sample and standard are placed in turn at the sample aperture and the ratio of the respective photocell readings determined. In the comparison method, both sample and standard are in place at all times at their respective apertures. The beam is switched from sample to standard and the ratio of the respective photocell readings determined. The efficiency and error, and their interdependence are discussed for both methods and for different geometries of the sphere. The design of a comparison type sphere with maximum efficiency and low error is considered.
227 citations
TL;DR: Using an ordinary transformer discharge, continuous emission spectra of krypton and argon similar to that of xenon reported recently were found in the regions from their resonance lines to about 1850 and 1650 A, respectively.
Abstract: Using an ordinary transformer discharge, continuous emission spectra of krypton and argon similar to that of xenon reported recently were found in the regions from their resonance lines to about 1850 and 1650 A, respectively. The characteristics of all the rare gas continua were similar regarding their dependence on excitation conditions as well as their features. The origin of these continua is explained by a process similar to that for the xenon continuum. The helium and neon continua are briefly discussed in connection with the present work.
160 citations
TL;DR: A survey of films and film combinations used for reflecting optics is given in this article, where the preparation and properties of unprotected mirror coatings, protective layers for front surface mirrors, reflection filters, and replica mirrors are discussed.
Abstract: This paper gives a survey of films and film combinations used for reflecting optics. The preparation and properties of unprotected mirror coatings, protective layers for front surface mirrors, reflection filters, and replica mirrors are discussed.
152 citations
TL;DR: The angular distribution of light scattered from a collimated beam incident upon a spherical air bubble in water is determined for any bubble with radius greater than a few wavelengths of the incident light as mentioned in this paper.
Abstract: The angular distribution of intensity of light scattered from a collimated beam incident upon a spherical air bubble in water is determined for any bubble with radius greater than a few wavelengths of the incident light. The computations are for wavelength 5893 A and n=1.3334, the relative index of refraction of water at 15°C. One external reflection, five internal reflections, and six refractions are considered. A general equation for the geometric attenuation factor is developed, with special forms for external reflection and for zero angle of incidence. The limits of accuracy of the equations for angles of scattering in the neighborhood of 0° and 180° are evaluated. The effects of diffraction and interference are assumed to be negligible. The fractions of the incident light scattered from each of the six “surfaces” (successive points of incidence of any ray on the spherical surface) are shown by accurate curves for all angles of deviation. The corresponding geometric attenutation factors are similarly shown. Final intensity values are tabulated and are plotted both with rectangular and with polar coordinates.
142 citations
TL;DR: In this paper, the spectral properties of CdS and ZnS in the spectral region from 0.6 micron to 14 microns were determined from spectrophotometric reflectance and transmittance measurements.
Abstract: The index of refraction and the absorption of evaporated films of CdS and ZnS in the spectral region from 0.6 micron to 14 microns were determined from spectrophotometric reflectance and transmittance measurements. The index of refraction of CdS ranged from 2.52 at 0.6μ to 2.26 at 14μ and was independent of deposition rate. The index of ZnS varied from 2.34 at 0.6μ to 2.15 at 14μ and was independent of deposition rate. The absorption coefficient of CdS depended upon the deposition rate from 0.6μ to 6μ and increased beyond 6μ independently of deposition rate. The absorption coefficient of ZnS was approximately 0.001 in the region of investigation. Approximate formulas are given for calculating the index of refraction and absorption from the reflectance and transmittance when the absorption is small. A method is given for preparing the phosphors that yields films for which the index of refraction is independent of the deposition rate. The crystalline structure was investigated by means of x-ray diffraction.
123 citations
TL;DR: In this article, a standard intensity scale for Raman bands in liquids has been proposed which is referred to the Raman band at 458 cm−1 in CCl4 taken under the same experimental conditions.
Abstract: A standard intensity scale for Raman bands in liquids has been proposed which is referred to the Raman band at 458 cm−1 in CCl4 taken under the same experimental conditions. Standard intensities are obtained from the photoelectrically registered spectra by correcting for convergence error, spectral sensitivity of the photomultiplier tube, optical density of the sample and reflection loss, and reduction to scattering per molecule. In all cases integrated intensities are used. Calculation of the effect of a triangular slit function on a Lorentz type Raman contour yields correction factors for converting the product of the peak intensity and the observed half band width to integrated intensities. Standard intensities are given for the Raman bands of liquid CH2Cl2, CHCl3, and CCl4. The apparent departure of the intensity from its linear dependence on concentration is also discussed.
109 citations
TL;DR: In this paper, exact expressions for the angular distribution coefficients were derived from the Mie equations for the scattering properties of a spherical particle, and the exact expressions were shown to be more convenient in form for tabulation of scattering properties and for application than the intensity functions used by Mie.
Abstract: Exact expressions have been derived from the Mie equations for the angular distribution coefficients, an, in the equation, f(θ)=14π+14π∑n=1∞anPn (cosθ),proposed by Hartel for the fraction of randomly polarized radiation scattered by a spherical particle into a unit solid angle in the direction θ. The coefficients are functions of the wavelength, particle diameter, and physical properties, and Pn (cosθ) are the Legendre polynomials. This equation is shown to be more convenient in form for tabulation of the scattering properties and for application than the intensity functions used by Mie and most subsequent investigators. Approximate methods for evaluating the coefficients were found to be inaccurate or inconvenient. The exact expressions, although detailed, are suitable for straightforward computation.
101 citations
TL;DR: It is concluded that the magnitude of photochemical events in the end organs does not limit localization accuracy for supraliminal stimuli and localization accuracy is independent of luminance and duration.
Abstract: Accuracy of localization of the radial position of a single stimulus was determined for various luminance-exposure duration combinations Localization accuracy, provided the stimulus is seen, is independent of luminance and duration, but varies with the radial position of the stimulus The results are discussed in terms of events critical to localization accuracy and it is concluded that the magnitude of photochemical events in the end organs does not limit localization accuracy for supraliminal stimuli
TL;DR: The thesis of this paper is that the only fully adequate way to describe the granularity of photographic materials is by means of a film noise spectrum, which bears the same relation to granularity that the power spectrum of electrical circuit theory bears to electrical noise.
Abstract: The thesis of this paper is that the only fully adequate way to describe the granularity of photographic materials is by means of a film noise spectrum. The film noise spectrum bears the same relation to granularity that the power spectrum (of electrical circuit theory) bears to electrical noise. The film noise spectrum includes all of the information in the previous granularity measures and readily interrelates them. It goes beyond the previous measures in that it leads to the solution of many of the signal-to-noise problems that arise in connection with the detection of target images on photographic materials.The film noise spectrum is defined and discussed in Parts 2 and 3. Its relation to the older methods of description involving granularity coefficients, both ordinary and syzygetic, is the subject of Part 4. The superiority of the new method is explained in detail in Part 5. Part 6 employs the film noise spectrum to derive the relation between ordinary granularity and syzygetic granularity. Part 7 discusses photoelectric scanning of the film and derives general expressions for the signal and for the noise. These expressions are used in Parts 8 and 9 to derive a particularly convenient method for the measurement of the film noise spectrum, and to solve the general problem of maximizing the signal-to-noise ratio in the detection of target images. Part 10 discusses the film noise spectrum of Super-XX film.
TL;DR: In this article, an apparatus for photographing Raman spectra of low-pressure gases at high dispersion is described, where a multiple reflection Raman tube, 2 m long, is irradiated by two water-cooled Pyrex mercury arcs operated at 30 amp, and surrounded by a magnesium oxide diffusing screen.
Abstract: An apparatus for photographing Raman spectra of low-pressure gases at high dispersion is described. A multiple reflection Raman tube, 2 m long, is irradiated by two water-cooled Pyrex mercury arcs operated at 30 amp, and surrounded by a magnesium oxide diffusing screen. A two-prism glass Littrow spectrograph, f/42, gives a reciprocal linear dispersion of 10.5 cm−1 per mm; its speed is increased fifteen-fold by a cylindrical lens in front of the photographic plate. Rotation-vibrational spectra of gases at 1–3 atmos pressure can be photographed with a resolution of 1 cm−1. Various aspects of high-resolution Raman spectroscopy of gases are discussed.
TL;DR: The minimum discriminable target velocity was determined with and without reference lines in the visual field and is interpreted as supporting the hypothesis that movement is discriminated at slow speeds by observation of change of position.
Abstract: The minimum discriminable target velocity was determined with and without reference lines in the visual field. At a short (0.125 sec) exposure duration, where velocity discrimination is determined primarily by the magnitude of initial photochemical events, the velocity threshold is not changed by the introduction of reference lines. At a long (16 sec) exposure duration, the presence of reference lines lowers the threshold velocity by 48%. The data are interpreted as supporting the hypothesis that movement is discriminated at slow speeds by observation of change of position.
TL;DR: An account of analytical techniques which provide a basis for a discussion of the problem of maximizing the information content in images formed by high-quality optical systems, by means of aberration balancing under prescribed constraints on the design is given.
Abstract: The informational aspects of optical design have attracted increasing attention in the last few years [see for example A Blanc-Lapierre (1953), D Gabor (1952)] The closely related topic of the Fourier treatment of optical imaging has been discussed by P-M Dufflieux (1946) and by Elias, Grey, and Robinson (1952) among others The present paper gives an account of analytical techniques which provide a basis for a discussion of the problem of maximizing the information content in images formed by high-quality optical systems, by means of aberration balancing under prescribed constraints on the design A derivation is given of the principal results needed for this purpose
TL;DR: In this article, a method for the preparation and mounting of thin aluminum oxide films from ordinary household aluminum foil is described, covering a circular area of 3.3 cm2 and as thin as 250 A were mounted on glass rings.
Abstract: A method for the preparation and mounting of thin aluminum oxide films from ordinary household aluminum foil is described. Free films covering a circular area of 3.3 cm2 and as thin as 250 A were mounted on glass rings. Infrared reflectance and transmission measurements show that there is absorption beyond 11 microns for even the thinnest films.
TL;DR: The report concerns a discussion of some methodological and statistical problems in testing color vision with the Nagel anomaloscope and an evaluation of records compiled during a period of four and a half years’ research work at the U. S. Air Force School of Aviation Medicine, Randolph Field, Texas.
Abstract: The report concerns a discussion of some methodological and statistical problems in testing color vision with the Nagel anomaloscope and an evaluation of records compiled during a period of four and a half years’ research work at the U. S. Air Force School of Aviation Medicine, Randolph Field, Texas. Following topics are dealt with: elimination of training effects and determination of the total number of readings required to detect specified minimum practical differences between individuals; application and frequency distribution of the anomalous quotient; determination of the normal matching range of mixtures and of comparison yellow; and test-retest reliability of the Nagel anomaloscope.
TL;DR: In this paper, the dispersion and aging effects of thin films of MgF2 and ZnS were investigated in the spectral range of 4000 A to 7500 A. The index of refraction was calculated from spectrophotometric reflectance measurements at extremes of reflectance.
Abstract: The dispersion and aging effects of thin films of MgF2 and ZnS were investigated in the spectral range of 4000 A to 7500 A. The method of evaporating ZnS is reported. The index of refraction was calculated from spectrophotometric reflectance measurements at extremes of reflectance.
TL;DR: In this article, a device for the convenient quantitative measurement of the thermal radiation from the atmosphere has been developed, where the emission spectrum of the earth's atmosphere as observed at ground level is compared automatically with a spectrum approximating that of a blackbody at the boiling point of liquid nitrogen at atmospheric pressure.
Abstract: A device for the convenient quantitative measurement of the thermal radiation from the atmosphere has been developed. In the instrument the emission spectrum of the earth’s atmosphere as observed at ground level is compared automatically with a spectrum approximating that of a blackbody at the boiling point of liquid nitrogen at atmospheric pressure. The most prominent features of the atmospheric spectrum between 4 μ and 15.5 μ, observed during daylight and darkness when the sky is clear, are due to emission by carbon dioxide, ozone, and water vapor; the intensity of the water vapor emission shows pronounced variations with atmospheric temperature and humidity. The spectrum of an overcast sky resembles that of a blackbody. By comparing the recorder traces of the atmospheric spectra with similar traces obtained with a blackbody source, it is possible to estimate the effective radiation temperature of various portions of the sky for various atmospheric conditions.
TL;DR: In this paper, the authors measured the absorption coefficients of O2 between 1320 A and 200 A using a 2-meter grazing incidence vacuum spectrograph and showed that the formation of the E layer at 100 km may be due to the absorption of solar radiation by the first ionization continuum.
Abstract: Absorption coefficients, k, of O2 between 1320 A and 200 A were measured using a 2-meter grazing incidence vacuum spectrograph. Three weak dissociation continua above 1040 A have been investigated. The “first continuum” between 1320 A and 1270 A had a maximum k-value of 13 cm−1 at 1295 A; another one between 1220 A and 1096 A was found to have a k=0.23 cm−1, and the third one between 1096 A and 1040 A had a value of about 3 cm−1. The absorption near Lyman α and in various other “atmospheric windows” in adjacent regions is given. Between 1040 A and 740 A strong absorption was observed due to diffuse bands, which were superimposed over the first ionization continuum with a maximum of 100 cm−1 at 920 A. The main ionization continuum had a long wavelength limit at 683 A and a flat maximum of 590 cm−1 at 510 A. (In addition low absorption coefficients of less than 1 cm−1 have been found in N2 between 1040 A and 910 A.) As an application of these data, a survey calculation on ionospheric absorption was made which showed that the formation of the E layer at 100 km may be due to the absorption of solar radiation by the first ionization continuum of O2. It is also shown that solar radiation between 1220 A and 1100 A can reach the height of the D layer by passing through the indicated atmospheric windows.
TL;DR: In this article, a photoelectric attachment for conventional types of visual precision polarimeters, utilizing the "method of symmetrical angles", has been developed, and its performance characteristics have been analyzed.
Abstract: A photoelectric attachment for conventional types of visual precision polarimeters, utilizing the “method of symmetrical angles,” has been developed, and its performance characteristics have been analyzed. A comparison of the precision of the photoelectric and visual observations indicates that they are of the same order when the mercury 546.1 mμ and sodium 589.25 mμ lines are used, provided that large apertures and high light transmission of samples can be maintained, and provided that the visual observations are made in a darkroom with a dark-adapted eye. In the case of micro and semimicro observations and samples of low light transmission, the photoelectric method yields a precision up to one order higher than that of visual measurements, with the additional benefits of reducing operator eye fatigue and eliminating the necessity of a darkroom.Methods of compensating for photometer drift, polarization effects in photomultiplier tubes, and high light absorption of samples are explained and an analysis of the problem of the optimum symmetrical angle is made.Errors in quartz control plate measurements indicate that more rigid specifications for color filters to be used with the sodium and mercury lamps must be developed to assure readings which agree with quartz control plate calibration values.
TL;DR: In this paper, a sealed-off hollow cathode discharge tube with iron electrodes and rare gas filling is described which will give an iron spectrum with very sharp lines and intensities of high reproducibility.
Abstract: A sealed-off hollow cathode discharge tube with iron electrodes and rare gas filling is described which will give an iron spectrum with very sharp lines and intensities of high reproducibility. Extensive data are given of the dependence of the iron intensities on the character of the rare gas, its pressure, and the discharge current. For most purposes a neon filling at about 3 mm pressure is recommended. The lines of such a tube are recommended for wavelength standards. They may serve as intensity standards with the proper precautions.
TL;DR: In this article, the rotational constants, B0 and D0, of CO were calculated using the method of least squares, and the resulting value of B0 with the value obtained from microwave frequency measurements, the velocity of light was estimated to be 299 792 km/sec.
Abstract: By infrared spectroscopy precise measurements of the wavelengths of forty-three rotational lines in the CO absorption band at 4.67 μ were made. Fifteen lines from J=32 to J=52 in the P branch were measured from the emission spectrum of CO. These data were reduced by the method of least squares, and values of the rotational constants, B0 and D0, of CO were calculated. A second, slightly less precise set of measurements over approximately the same range of J values was similarly reduced, and combined estimates of the constants were obtained. Using the resulting value of B0 with the value obtained from microwave frequency measurements, the velocity of light was estimated to be 299 792 km/sec. The estimated standard deviation of this value is 6 km/sec.
TL;DR: In this paper, a 14-inch ruling engine with interferometer control of grating blank position between ruling strokes has been described, which is now being operated with continuous blank advance and control.
Abstract: A 14-inch ruling engine, whose operation with interferometer control of grating blank position between ruling strokes has been described previously, is now being operated with continuous blank advance and control. Displacement of the carriage holding the grating blank is measured in terms of the phase of a fringe system of constant inclination passing across a photoelectric pickup, which produces low-frequency ac whose phase is compared with that from a generator measuring the phase of motion of the ruling diamond. Synchronism between diamond and blank is maintained through corrections fed into a differential on the engine screw-worm by a balancing motor operated by phase differences. Grooves straight to one-tenth fringe, up to 9 in. long, can be produced by means of a cam-and-lever system which rectifies the otherwise simple harmonic motion of the diamond carriage. Continuous servo control results in improved elimination of screw errors and engine vibrations, and in simplified circuitry. The needed electronic and interferometric control systems have been found to function reliably over the long periods needed to rule large gratings.A change-gear system permits passage of any desired fractional number of fringes per diamond stroke needed to produce from about 50 000 to 2000 grooves per inch. The signal-to-noise ratio obtained when green light from an Hg-198 tube is used to illuminate the carriage-translation interferometer is found to permit control over 10 in. of carriage motion, and stepping methods are being studied to permit multiplication of this distance. Plane gratings up to 8 in. in width of ruling and 5 in. in groove length have been produced, which show acceptably low ghost intensities despite original screw errors of more than 50 times the tolerance limit. Error-of-run and fanning appear to be under good control over distances of 8 in. Rapidly occurring random errors previously found have been traced to lateral motion of the diamond carriage and eliminated. Slow irregularities in groove position are ascribed to temperature variations, to which the engine has been found to be 10 times as sensitive as necessary; these are now being removed. Continuous oscilloscope records taken during ruling show that blank positioning is being controlled by servo interferometry to within 1/40 fringe or better, and indicate sources of disturbances whose removal should result in further improvement.
TL;DR: In this paper, a new vacuum ultraviolet light source is described which emits a continuous spectrum from 1250 to 1650 A. The electrodeless source, charged with 190 mm of krypton, is operated with microwave power at 2450 Mc/sec, and is completely sealed off from the pumping system.
Abstract: A new vacuum ultraviolet light source is described which emits a continuous spectrum from 1250 to 1650 A. The electrodeless source, charged with 190 mm of krypton, is operated with microwave power at 2450 Mc/sec, and is completely sealed off from the pumping system. It has been used with a 21 ft vacuum spectrograph to photograph the absorption spectrum of benzene vapor in the 1350 to 1550 A region.
TL;DR: There is a range of intensities over which relative spectral sensitivity does not change appreciably from the scotopic luminosity function, and there are irregularities in these mesopic curves which may be attributed to cone activity.
Abstract: Spectral sensitivity curves were established for three intensity levels above scotopic threshold with a two-degree field placed ten degrees from fixation against a dark surround. These curves were compared with the minimum scotopic luminosity curve determined for the same retinal position for each observer. The results showed that (1) there is a range of intensities over which relative spectral sensitivity does not change appreciably from the scotopic luminosity function, (2) there are irregularities in these mesopic curves which may be attributed to cone activity, and (3) the first change in spectral sensitivity with increased intensity is found in the long-wavelength half of the spectrum.
TL;DR: In this paper, the spectral reflectivity of electrostatically deposited magnesium oxide smoke coating from thicknesses of 0.2 mm to 8.0 mm was measured using a photometric sphere.
Abstract: Measurements have been made of the spectral reflectivity of electrostatically deposited magnesium oxide smoke coating from thicknesses of 0.2 mm to 8.0 mm. The theory of the photometric sphere was used to determine the coefficient of reflection. A glass sphere was used to avoid the reflective effects of an opaque material and to determine the uniformity of the coating. It was found that at 8.0 mm thickness, light from a source placed inside the sphere could be visibly detected through the coating. For thick coatings, the reflectivity was in good agreement with that reported by Benford, Lloyd, and Schwartz. However, at the thinner coatings the results were in reasonable agreement with Middleton and Sanders’ results. The color inside the illuminated sphere depended upon the coating thickness, and changed from a bluish cast through green to ivory as the thickness increased.
TL;DR: By a simple adaptation of disk colorimetry the hues of negative after-images of colored surfaces are ascertained to within the equivalent of 1.0 step of Munsell hue, and complementary pairs thus obtained show differences from those established additively.
Abstract: By a simple adaptation of disk colorimetry the hues of negative after-images of colored surfaces are ascertained to within the equivalent of 1.0 step of Munsell hue. There is good agreement among a number of observers. The complementary pairs thus obtained show differences from those established additively, particularly in the orange-blue region. The relationship between the two sets of complementaries appears to be connected with the change of hue which occurs when colors are desaturated by additive mixture. This change of hue also accounts for the nonuniform spacing of hues which is a necessary feature of color circles based on additive complementary pairs.From the observed changes of hue over a range of colors, lines of constant hue are plotted.
TL;DR: An analysis has been made of the Y values, or luminances, of 342 colored filters which had been previously matched in brightness by direct visual comparison to show that, for colors of equal brightness, saturated colors require less luminance than desaturated ones.
Abstract: An analysis has been made of the Y values, or luminances, of 342 colored filters which had been previously matched in brightness by direct visual comparison. The CIE diagram was partitioned into 20 zones and the average luminance calculated for the colors in each zone. The results show regular shifts in the average luminance values over the CIE diagram. Supplementary experiments support the principal findings. In general, the data agree with other recent studies which show that, for colors of equal brightness, saturated colors require less luminance than desaturated ones. However, there is a reversal of this trend in the yellow area since the point of maximum luminance for a given brightness occurs there. The latter finding agrees closely with recent predictions by MacAdam based on his model of visually homogeneous color space.