Abstract

The experiments reported in this paper are similar to the famous Abbe experiments. However, they were done for quite different reasons, namely, to perform certain information processing operations by optical means. Our technique, called theta modulation, allows production of a color image from a black and white film, on which the color object is recorded in encoded form. Furthermore, nonlinear characteristics (H & D curves) of any shape can be realized. A special application of theta modulation, called multiplex storage, will be described. By this technique, more than one image can be recorded in the same area on a piece of film. Subsequently, the individual images can be recovered with a minimum of crosstalk.

© 1965 Optical Society of America

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References

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  1. W. E. Glenn, J. Opt. Soc. Am. 48, 841 (1958); J. Appl. Phys. 30, 1870 (1959).
    [Crossref]
  2. A. Lohmann, B. Morgenstern, Optik 20, 450 (1963).
  3. E. Lau, W. Krug, Die Aequidensitometrie (Akademie-Verlag, Berlin, 1957).
  4. J. S. Courtney-Pratt, J. Soc. Motion Picture Television Engrs. 72, 876 (1963).
  5. H. J. Zweig, G. C. Higgins, D. L. MacAdam, J. Opt. Soc. Am. 48, 926 (1958).
    [Crossref]

1963 (2)

A. Lohmann, B. Morgenstern, Optik 20, 450 (1963).

J. S. Courtney-Pratt, J. Soc. Motion Picture Television Engrs. 72, 876 (1963).

1958 (2)

Courtney-Pratt, J. S.

J. S. Courtney-Pratt, J. Soc. Motion Picture Television Engrs. 72, 876 (1963).

Glenn, W. E.

Higgins, G. C.

Krug, W.

E. Lau, W. Krug, Die Aequidensitometrie (Akademie-Verlag, Berlin, 1957).

Lau, E.

E. Lau, W. Krug, Die Aequidensitometrie (Akademie-Verlag, Berlin, 1957).

Lohmann, A.

A. Lohmann, B. Morgenstern, Optik 20, 450 (1963).

MacAdam, D. L.

Morgenstern, B.

A. Lohmann, B. Morgenstern, Optik 20, 450 (1963).

Zweig, H. J.

J. Opt. Soc. Am. (2)

J. Soc. Motion Picture Television Engrs. (1)

J. S. Courtney-Pratt, J. Soc. Motion Picture Television Engrs. 72, 876 (1963).

Optik (1)

A. Lohmann, B. Morgenstern, Optik 20, 450 (1963).

Other (1)

E. Lau, W. Krug, Die Aequidensitometrie (Akademie-Verlag, Berlin, 1957).

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Figures (11)

Fig. 1
Fig. 1

Principle of theta modulation. (a) Object with grey ladder; (b) same object in theta-modulated form.

Fig. 2
Fig. 2

Optical arrangement for theta demodulation. S = source; M = plane for modulated object; F = Fraunhofer plane, the place for the demodulation mask; B = image plane, where the demodulated object appears.

Fig. 3
Fig. 3

Three objects with corresponding Fraunhofer diffraction pattern.

Fig. 4
Fig. 4

Modulated object, diffraction pattern, and demodulation mask.

Fig. 5
Fig. 5

Result of demodulation procedure for one modulated object with two different demodulation masks.

Fig. 6
Fig. 6

Color encoding by theta modulation. Each hexagonal object element consists of three gratings, assigned to the three color components here, four object elements: blue, green, red, and blue-green. The demodulation mask consists of transparent and opaque sectors, superimposed by color filters.

Fig. 7
Fig. 7

Color demodulation. The radial structure of the demodulation mask is responsible for color generation, assuming polychromatic light.

Fig. 8
Fig. 8

Equidensity process. Linear modulation I0θ; demodulation mask T(θ) with two small sectors, generating equidensity lines in the image IB at levels I1 and I2.

Fig. 9
Fig. 9

Multiplex principle. Two signals S0(x) and S1(x) are combined to S(x) = S0(x) + 2S1(x). Extraction of either S0 or S1 is possible by nonlinear process of characteristic S0(S) or S1(S).

Fig. 10
Fig. 10

Multiplex storage. (a) Two binary signals multiplexed and theta-modulated; their Fraunhofer diffraction spectrum; (b), (c) extraction of the two signals, together with corresponding demodulation masks.

Fig. 11
Fig. 11

Modulation process. CRT scanning of object I0(x,y). Second CRT with grid source. Rotation (theta) of grid images as parts of IM by means of yoke. Yoke current proportional to photoelectric signal from first CRT. Synchronous and pulsed deflection of both CRT’s and synchronously blanked grid source.

Equations (6)

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θ ( x , y ) = K I 0 ( x , y ) ,             K = π / max ( I 0 ) .
S n ( x , y ) = [ 1 or 0 ] ;             n = 0 , 1 , 2 , , N - 1
S ( x , y ) = 0 N - 1 2 n S n ( x , y ) = 0 or 1 or 2 or , , or 2 n - 1.
S m ( S ) = { 1 if 2 m ( 1 + 2 p ) S < 2 m + 1 ( 1 + p ) 0 otherwise ; p = 0 , 1 , , 2 N - m - 1 - 1.
S 0 ( x , y ) = { 1 if AIP white 0 if AIP black S 1 ( x , y ) = { 1 if OSA white 0 if OSA black .
θ ( x , y ) = 1 4 π S ( x , y ) .

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