Imaging path speckle mitigation
View Patent ↗Disclosed herein are optical projection systems and related methods for projecting imagery employing shifting image position in-time to mitigate speckle. Exemplary optical systems may include a projector having a light source, a relay lens and at least one projection lens for projecting images. The relay lens or the projection lens may have at least one lens element that may be translated in-time substantially orthogonal to the optical axis of the optical system. Alternatively, the projection lens in its entirety may be shifted in-time to reduce speckle. Further, in stereoscopic embodiments, two projection lenses may be employed, wherein at least one element in each projection lens is moveable to shift the image in-time to reduce speckle. Moreover, electronic compensation, such as electronic addressing or image warping, for the image shifting may be employed to shift the image in a direction opposite to the speckle-reducing shift in position.
1. An optical system, comprising:
a light source for illuminating a pixel panel;
a relay lens in an image path of the pixel panel and light source configured to relay an intermediate image of the pixel panel; and
at least one projection lens for projecting the intermediate image received from the relay lens onto a screen, wherein at least a portion of the relay lens or the projection lens is translatable substantially orthogonal to an optical axis of the optical system in-time to shift a position of the projected imagery on the screen.
2. An optical system according to claim 1 , wherein a single lens element within the relay lens is translatable by a portion of a pixel size of the pixel panel to provide approximately a half-pixel image shift in the projected imagery on the screen.
3. An optical system according to claim 1 , wherein the relay lens is a double-Gauss system comprising two outer lenses and two inner cemented menisci, symmetrically arranged around an aperture.
4. An optical system according to claim 1 , wherein the optical system is a stereoscopic display system comprising two projection lenses, and wherein at least one lens element in each of the projection lenses is translatable in-time to shift a position of the projected imagery on the screen.
5. An optical system according to claim 1 , wherein the optical system is a stereoscopic display system comprising two projection lenses and a polarization conversion system, wherein a polarizing beam splitter of the polarization conversion system is rotatable about an axis substantially perpendicular to the optical axis in-time to shift a position of the projected imagery on the screen thereby mitigating imagery speckle.
6. An optical system according to claim 1 , wherein the light source is a laser light source.
7. An optical system according to claim 1 , wherein the projection lens in its entirety is translatable in-time to shift a position of the projected imagery on the screen.
8. An optical system according to claim 1 , further comprising an electronic addressing sub-system configured to shift the imagery on the pixel panel using electronic addressing in a direction opposite of the shift provided by the translation of the at least one portion.
9. An optical system according to claim 1 , further comprising an image warping sub-system configured to shift the imagery on the pixel panel using image warping in a direction opposite of the shift provided by the translation of the at least one portion.
10. An optical system according to claim 1 , wherein at least a portion of the relay lens or the projection lens is translatable substantially orthogonal to an optical axis of the optical system in-time to shift a position of the projected imagery on the screen thereby mitigating imagery speckle.
11. A method for mitigating imagery speckle in an optical system, the method comprising:
illuminating imagery on a pixel panel with a light source;
relaying an intermediate image of the pixel panel using a relay lens positioned in an image path generated by the light source;
projecting the intermediate image received from the relay lens with at least one projection lens onto a screen; and
shifting a position of the projected imagery on the screen by translating at least a portion of the relay lens or the projection lens substantially orthogonal to an optical axis of the optical system in-time.
12. A method according to claim 11 , wherein shifting a position of the projected imagery on the screen comprises translating a single lens element within the relay lens by a portion of a pixel size of the pixel panel to provide an approximately half-pixel image shift in the projected imagery on the screen.
13. A method according to claim 11 , wherein the relay lens is a double-Gauss system comprising two outer lenses and two inner cemented menisci, symmetrically arranged around an aperture.
14. A method according to claim 11 , wherein the optical system is a stereoscopic display system comprising two projection lenses, and wherein shifting a position of the projected imagery on the screen comprises translating at least one lens element in each of the projection lenses in-time to shift a position of the projected imagery on the screen.
15. A method according to claim 11 , wherein the optical system is a stereoscopic display system comprising two projection lenses and a polarization conversion system, and wherein shifting a position of the projected imagery on the screen further comprises rotating a polarizing beam splitter of the polarization conversion system about an axis substantially perpendicular to the optical axis in-time to shift a position of the projected imagery on the screen thereby mitigating imagery speckle.
16. A method according to claim 11 , wherein the light source is a laser light source.
17. A method according to claim 11 , wherein shifting a position of the projected imagery on the screen comprises translating the projection lens in its entirety substantially orthogonal to an optical axis of the optical system in-time to shift a position of the projected imagery on the screen.
18. A method according to claim 11 , further comprising shifting the imagery on the pixel panel in a direction opposite of the shift provided by the translation of the at least one portion.
19. A method according to claim 18 , wherein shifting the imagery in a direction opposite of the shift provided by the translation of the at least one portion comprises using electronic addressing or image warping of the imagery on the pixel panel.
20. A method according to claim 11 , further comprising shifting a position of the projected imagery on the screen by translating at least a portion of the relay lens or the projection lens substantially orthogonal to an optical axis of the optical system in-time to thereby mitigating imagery speckle.
21. A stereoscopic optical projection system, comprising:
a laser light source for illuminating a pixel panel;
a relay lens in an image path generated by the pixel panel and the light source configured to relay an intermediate image of the pixel panel; and
a first and second projection lens for projecting stereoscopic intermediate imagery received from the relay lens onto a screen, wherein a position of the projected stereoscopic imagery on the screen is moveable in-time.
22. A stereoscopic optical projection system according to claim 21 , wherein at least one lens element within the relay lens is translatable substantially orthogonal to an optical axis of the optical system in-time to shift the position of the projected stereoscopic imagery on the screen.
23. A stereoscopic optical projection system according to claim 21 , wherein at least one lens element within each of the projection lenses is translatable substantially orthogonal to an optical axis of the optical system in-time to shift the position of the projected stereoscopic imagery on the screen.
24. A stereoscopic optical projection system according to claim 21 , wherein the relay lens is a double-Gauss system comprising two outer lenses and two inner cemented menisci, symmetrically arranged around an aperture.
25. A stereoscopic optical projection system according to claim 21 , wherein the optical system further comprises a polarization conversion system for providing the stereoscopic imagery to the projection lenses, wherein a polarizing beam splitter of the polarization conversion system is rotatable about an axis substantially perpendicular to the optical axis in-time to shift the position of the projected imagery on the screen.
26. A stereoscopic optical projection system according to claim 21 , wherein the projection lens in its entirety is translatable in-time to shift the position of the projected stereoscopic imagery on the screen.
27. A stereoscopic optical projection system according to claim 21 , further comprising an electronic addressing sub-system configured to shift the imagery on the pixel panel using electronic addressing in a direction opposite of the shift of the position of the projected stereoscopic imagery on the screen.
28. A stereoscopic optical projection system according to claim 21 , further comprising an image warping sub-system configured to shift the imagery on the pixel panel using image warping in a direction opposite of the shift of the position of the projected stereoscopic imagery on the screen.
29. A stereoscopic optical projection system according to claim 21 , wherein the position of the projected stereoscopic imagery on the screen is moveable in-time thereby mitigating imagery speckle.