Stereoscopic process and apparatus using diffractive optical elements

• US 4,717,239 A
• Filed: 03/04/1986
• Issued: 01/05/1988
• Est. Priority Date: 01/05/1984
• Status: Expired due to Term

• Current Assignee: Georgia Tech Research Corporation (University System of Georgia)
• Original Assignee: Georgia Tech Research Corporation (University System of Georgia)
• Inventors: Steenblik, Richard A.
• Primary Examiner(s): NOT, DEFINED
• Application Number:
  US06/835,948
• Time in Patent Office: 672 Days
• Field of Search: 350/144, 350/130-132, 350/3.7, 350/162.17, 350/162.18, 350/168, 350/286, 350/287, 350/145, 350/320
• US Class Current: 359/478
• CPC Class Codes: G02B 30/23 using wavelength separation, e.g. using anaglyph techniques
• CPC Class Codes: G02B 30/36 using refractive optical elements, e.g. prisms, in the optical path between the images and the observer
• CPC Class Codes: G02B 5/04 Prisms
• CPC Class Codes: G02B 5/06 Fluid-filled or evacuated prisms
• CPC Class Codes: G02C 2202/20 Diffractive and Fresnel lenses or lens portions
• CPC Class Codes: G02C 7/02 Lenses; Lens systems ; Methods of designing lenses
• CPC Class Codes: G02C 7/14 Mirrors; Prisms
• CPC Class Codes: H04N 13/324 Colour aspects
• CPC Class Codes: H04N 13/334 using spectral multiplexing
• CPC Class Codes: H04N 13/337 using polarisation multiplexing
• CPC Class Codes: H04N 13/339 using spatial multiplexing H04N13/337 takes precedence

Abstract

A method and apparatus for producing and viewing stereoscopic images through the use of a color coded image whereby the desired depth or distance is based upon the color of the portion of the image being viewed. Therefore the parts of the image which are to appear distant are colored red whereas the parts of the image to appear in the foreground are colored blue with the middle ground or intermediate distances being colored green or yellow. The color coded image is viewed through a prism glass constructed so that blue light which passes through the prism is bent toward a sharper angle than red light. Because the apex of the prism before each eye points toward the nose or center of the glasses the eyes must then turn more inward to see a blue object than to see a red object even though they are in actuality in the same plane on the display. This leads to brain to interpret, by means of parallax, that the blue image is closer and the red image is more distant unless the parallax is greatly contradicted by other depth clues such as relative size, position and perspective. In a preferred form, a double prism is used for each eye in order to eliminate single prism problems such as visual disorientation and eye strain.

Claims

1. A method for producing and viewing stereoscopic images, comprising the steps of:

color coding each portion of an image to be viewed according to the desired depth appearance of said portion with respect to the remaining portions of said image; and

viewing said image through a viewer means which passes light of a chosen color without imparting an angular deviation to said light from its original path, and which deviates light of other colors to either side of the chosen color with respect to the chosen color, and said color coded portion of said image appearing at said desired appearance depth wherein said viewer means includes at least one optical element for each of the left and right eye wherein the at least one optical element is a diffractive optical element.

2. The method of claim 1 whereby said color coding step further includes color coding as red the portion of said image which is to appear most distant from said viewer means and color coding as blue the portion of said image which is to appear nearest to said viewer means.

3. The method of claim 2 wherein said color coding step further includes coloring the portions of said image which are to appear between said most distant portion and said nearest portion as one of orange, yellow, yellow-green, and blue-green in accordance with the respective distance from said portion to appear most distant from said viewer means.

4. The method of claim 1 wherein said color coding step is accomplished through the use of pure colors.

5. The method according to claim 1 wherein the step of color coding each portion is modified by the natural appearance, size and natural color of said each portion.

6. The method according to claim 1 wherein said step of viewing said image through said viewer means is accomplished through the use of a computer generated color image.

7. The method of claim 1 whereby said color coding step further includes color coding as blue, the portion of said image which is to appear most distant from said viewer means and color coding as red, the of said image which is to appear nearest to said viewer means.

8. The method of claim 1 wherein said viewer means further includes at least one refractive optical element for each of the left and right eye.

9. The method of claim 1 wherein the at least one diffractive optical element is holographically generated.

10. The method of claim 8 wherein the at least one diffractive optical element is holographically generated.

11. The method of claim 1 wherein said viewing step further comprises the steps of:

chromatically dispersing all colors of light through various angles dependent upon the spectral position of each color; and

centering said chosen color of light relative to said light of other colors by angularly deflecting said other colors of light through an angle substantially equal and opposite to the angle of said chromatic dispersion of said chosen color of light.

12. The method of claim 11 wherein said dispersing and centering steps are performed simultaneously.

13. The method of claim 11 wherein said dispersing and centering steps are performed sequentially.

14. The method of claim 11 wherein said dispersing and centering steps are performed by the at least one diffractive optical element.

15. The method of claim 11 wherein one of said dispersing and centering steps is performed by the at least one diffractive optical element and the other of said steps is performed by at least one refractive optical element.

16. The method of claim 14 wherein the at least one diffractive optical element is holographically generated.

17. The method of claim 15 wherein the at least one diffractive optical element is holographically generated.

18. The method of claim 15 wherein the at least one refractive optical element is a prism.

19. A stereoscopic system for producing and viewing an image, comprising:

a color coded image;

having each portion of the image to be viewed colored according to the desired appearance depth of said portion with respect to the remaining portions of said image; and

viewing means including at least one optical element for each of the left and right eye wherein the at least one optical element is a diffractive optical element for viewing said image through the viewer means which passes light of a chosen color without imparting an angular deviation to said light from its original path, and which deviates light of other colors to either side of the chosen color through various angles according to the spectral relationship of each color with respect to the chosen color, and said color coded portions of said image appearing at said desired appearance depth.

20. The system of claim 19 wherein said color coded image has a red color for the portion of said image which is to appear most distant from said viewer means and a blue color for the portion of said image which is to appear nearest to said viewer means.

21. The system of claim 20 wherein said color coded image has the portions of said image which are to appear between said most distant portion and said nearest portion as one of orange, yellow, yellow-green, and blue-green color in accordance with the respective distance from said portion to appear most distant from said viewer means.

22. The system of claim 19 wherein said colors of said image are pure, nearly monochromatic colors.

23. The system according to claim 19 wherein the color coding of each portion is modified by the natural appearance, size and natural color of said each portion.

24. The system of claim 19 wherein said viewer means further comprises means for chromatically dispersing all colors of light through various angles dependent upon the spectral position of each color, and means for centering said chosen color of light relative to said light of other colors by angularly deflecting said light through an angle substantially equal and opposite to the angle of said chromatic dispersion of said chosen color of light.

25. The system of claim 24 wherein the chromatically dispersing means and the angularly deflecting means comprise the at least one diffractive element.

26. The system of claim 24 wherein one of said dispersing or centering means is performed by the at least one diffractive optical element and the other of said means is performed by at least one refractive optical element.

27. The system of claim 25 wherein the at least one diffractive optical element is holographically generated.

28. The system of claim 26 wherein the at least one diffractive optical element is holographically generated.

29. The system of claim 26 wherein the at least one refractive optical element is a prism.

30. The system according to claim 19 wherein said image means is color coded by a computer generated color image.

31. The system of claim 19 wherein said color coded display has a blue color for the portion of said image which is to appear most distant from said viewer means and a red color for the portion of said image which is to appear nearest to said viewer means.