Image scrambling technique

• US 3,914,877 A
• Filed: 04/08/1974
• Issued: 10/28/1975
• Est. Priority Date: 04/08/1974
• Status: Expired due to Term

• Current Assignee: Marion E. Hines
• Original Assignee: Marion E. Hines
• Inventors: Hines, Marion E.
• Primary Examiner(s): Reich, Joseph S.
• Assistant Examiner(s): Wolff, John H.
• Application Number:
  US05/458,783
• Time in Patent Office: 568 Days
• Field of Search: 35/2 283/6,7
• US Class Current: 380/54
• CPC Class Codes: G07C 9/243 visually, e.g. by comparing in a viewer the written signature with a reference on the pass
• CPC Class Codes: G09C 5/00 Ciphering apparatus or methods not provided for in the preceding groups, e.g. involving the concealment or deformation of graphic data such as designs, written or printed messages
• CPC Class Codes: H04N 1/448 Rendering the image unintelligible, e.g. scrambling

Abstract

An unreadable scrambled image is prepared from an original image of a signature or other written matter, by a special photographic procedure involving the use of a code plate which contains a complex but unique and reproducible pattern of light and dark marks representing a numerical binary code by which the image is transformed. This scrambled image is not interpretable by ordinary examination. The scrambled image may be unscrambled and read by an authorized recipient if he possesses a copy of the original code plate, simply by placing the two in intimate contact and viewing the combination.

Claims

1. For confidential communication of the information contained in a source image consisting of a pattern of light and dark regions, a method of making an uninterpretable encoded image thereof and of restoring the said information pattern into an interpretable form from said encoded image, said method constituting the following steps:

a. designating a finite and denumerable array of discrete points in a two dimensional geometric surface in which said points are regularly spaced in a repetitive and periodic manner with their relative positions established to permit their location on various material surfaces;

b. assigning to each of said points one or the other of two binary code descriptors selected in a random or pseudo-random manner to form, in the entire set of assignments, a distinctive code;

c. making a record of said code assignments for future use;

d. locating said array of points on the surface of said source image and sampling said image at each of said points to determine if it lies in a dark or a light region;

e. determining a binary message designator for each of said points following a set of logical rules of substitution wherein the choice is dependent upon the said determination of light or dark and upon the binary code descriptor assigned to that point. f. making a record of said binary message designators on a message surface, consisting of an array of binary symbols arranged in the pattern of said array of points to provide said encoded image;

g. providing, at the place of destination of said communication, said encoded image and said record of code assignments;

h. providing a restoration surface upon which said restoration is to be observed;

i. producing, on said restoration surfaCe at the locations of said points of said array, local non-overlapping zones of light or dark appearance for which the choice of light or dark is determined by a set of logical rules of substitution depending upon the binary symbol recorded at each such point of said array on the said encoded image and upon the said binary code assignment for the corresponding point such that said zone of appearance is light if said original image was light and dark if said original image was dark at such point, or vice versa in all cases, the pattern of said light and dark zones of appearance constituting said restoration of said information.

2. on the first of said surfaces, placing a visible spot at each of the said points to which has been assigned the said first type of binary code descriptor;

3. The method according to claim 2 wherein the recorded symbols on said encoded image record are local zones of light or dark appearance and wherein the restoration of the information pattern of the source image is accomplished by optically combining one of said code-plate images with said encoded image with said arrays of spots and zones of appearance in register, said combined images constituting said restoration.

4. The method according to claim 3, wherein one of the following conditions exists:

a. said code plate is transparent at said spots;

b. said light zones of appearance on said encoded image are transparent; and

c. both (a) and (b) exist simultaneously; and

wherein said images are combined by overlying one with the other in register.

5. For confidential communication of the information contained in a source image consisting of a pattern of light and dark regions, a method of making an uninterpretable encoded image thereof and restoring, at the place of destination of communication, the said information pattern into an interpretable form from said encoded image, said method constituting the following steps:

a. preparing a first code plate consisting of a distribution of minute transparent optical apertures in an otherwise opaque surface;

b. preparing a second code plate as in (a) but with a different arrangement of apertures;

c. providing a positive transparency image of said source image in which said light regions are transparent and said dark regions are opaque;

d. providing a negative transparency image of said source image in which said light regions are made opaque and said dark regions are made transparent;

e. providing a photosensitive plate to receive said encoded image;

f. overlaying said photosensitive plate with said positive transparency image and said first code plate and optically exposing said photo sensitive plate through said overlays;

g. overlaying said photosensitive plate with said negative transparency image and said second code plate and providing a second optical exposure of said photosensitive plate Through said overlays;

h. developing said photosensitive plate to provide said encoded image;

i. at the place of destination of communication, providing said encoded image;

j. providing one of said code plates or a reproduction thereof;

k. overlaying said encoded image with said code plate in register and viewing the combination to provide said restoration of said information.