Method and apparatus for color identification

• US 4,731,663 A
• Filed: 05/20/1987
• Issued: 03/15/1988
• Est. Priority Date: 05/20/1987
• Status: Expired due to Term

• Current Assignee: American Telephone & Telegraph Company (AT&T, Inc.)
• Original Assignee: American Telephone & Telegraph Company (AT&T, Inc.)
• Inventors: Kovalchick, Joseph S., Sikorski, Theodore J., Treder, Ralph A.
• Primary Examiner(s): Britton, Howard W.
• Application Number:
  US07/052,101
• Time in Patent Office: 300 Days
• Field of Search: 358/101, 358/106, 356/394, 356/402, 356/405, 356/406, 356/416, 356/425, 382/8, 382/17, 379/25
• US Class Current: 382/165
• CPC Class Codes: G01J 2003/466 Coded colour; Recognition of predetermined colour; Determining proximity to predetermined colour
• CPC Class Codes: G01J 3/46 Measurement of colour; Colour measuring devices, e.g. colorimeters measuring colour temperature G01J5/60
• CPC Class Codes: G01R 31/60 Identification of wires in a multicore cable

Abstract

The color of each of a plurality of wires 18(1) . . . 18(8) can be determined by first placing the wires proximate to a white background (31) and then directing a pair of light beams (36,38) thereat. Each of the red, green and blue spectral components in the light reflected from each wire and in the light reflected from the surface is simultaneously sensed by a separate one of three television cameras (40,42 and 44), respectively, having a separate one of a set of red, green and blue band pass filters (52,54 and 56), respectively, thereon. The output signal of the television cameras is processed by a machine vision system (58) which first computes the ratios of the red, green and blue spectral components of the light reflected from each wire to the red, green and blue spectral components, respectively, of the light reflected from the background. Each of the red, green and blue intensity ratios computed for each wire is then compared by the machine vision system to a red, green and blue intensity ratio, respectively, established for each of a plurality of wires of known colors until a substantial match therebetween is found. When a substantial match is found, the wire of unknown color can then be identified.

Claims

1. A method of fabricating an article comprising the steps of:

identifying the color of an object by illuminating the object, sensing the intensity of each of a plurality of spectral components in the light reflected from the object, and comparing the intensity values to each of a standard set of intensity values associated with each of a plurality of known colors; and

completing the fabrication of said article in accordance with the color of said object, characterized in that said identifying step further includes the steps of;

placing the object proximate to a background which is of a color uniquely distinguishable from the possible colors of said object;

illuminating said background simultaneously with said object;

sensing each of said plurality of spectral components in the light reflected from said background, simultaneously with sensing the spectral components in the light reflected from the object;

computing the ratio of the intensity of each spectral component of the light reflected from said object to the corresponding spectral component of the light reflected from said background; and

comparing the computed intensity ratios to each of a set of intensity ratios established for each of a set of reference bodies of different known colors placed proximate to said background until a substantial match is found between each of the computed intensity ratios and each of the intensity ratios of a set associated with a reference body having a particular color.

2. The method according to claim 1, characterized in that said sensing step comprises the step of sensing the intensity of the red, green ad blue spectral components in the light reflected from said object and of the light reflected from said background.

3. The method according to claim 2, characterized in that said sensing step includes the step of filtering the light incident on each of three separate sensing means to each senses the red, green and blue light, respectively, reflected from said object and said background simultaneously.

4. The method according to claim 2, characterized in that said sensing step includes the step of sequentially filtering the light incident on a single light-sensing means so said sensing means successively senses the red, green and blue light reflected from said object and said background.

5. The method according to claim 2, characterized in that said sensing step includes the step of spatially filtering the light incident on a single sensing means so said sensing means senses the red, green and blue light reflected from three spatially separated areas, respectively, on said object and said background.

6. The method according to claim 1, characterized in that said set of intensity ratios associated with each said reference body is established by a method comprising the steps of:

placing each said reference body proximate to the background;

simultaneously illuminating said background and said reference body placed proximate thereto;

sensing the intensity of each of a plurality of spectral components in the light reflected from said reference body simultaneously with the corresponding spectral components in the light reflected from said background; and

computing the ratio of the intensity of each of said spectral components in the light reflected from said reference body to the corresponding spectral component in the light reflected from said background.

7. The method according to claim 1, characterized in that said object to be identified comprises a wire formed of an electrical conductor sheathed by a colored insulative jacket.

8. Apparatus for identifying the color of an object comprising:

a background proximate to which said object is placed, said background being of a color which is uniquely distinguishable from the possible colors of said object;

means for simultaneously illuminating said background and object placed proximate thereto; and

means for sensing the intensity of each of a plurality of spectral components of the light reflected from said object and of the light reflected from said background, characterized in that said apparatus further includes;

means for computing the ratio of the intensity of each spectral component of the light reflected from said object to the corresponding spectral component of the light reflected from said background; and

means for comparing each of the computed ratios to each of a set of intensity ratios associated with a separate one of a plurality of reference bodies of different known colors until a substantial match is found between one of the computed intensity ratios and each of the intensity ratios within the set associated with the reference body of a particular color.

9. The apparatus according to claim 8, characterized in that said sensing means comprises three television cameras, each having a band pass filter thereon for passing only the red, green and blue spectral components, respectively, of the light reflected from said object and of the light reflected from said surface.

10. The apparatus according to claim 8, characterized in that said sensing means comprises a single television camera having each of three light filtering means superimposed thereon for selectively passing only red, green and blue light, respectively.

11. The apparatus according to claim 8, characterized in that said sensing means comprises a single television camera having a stripe filter thereon for passing only red, green and blue light reflected from three separate areas on said background.

12. The apparatus according to claim 8, characterized in that said computing means and said comparing means are jointly comprised of a machine vision system.