Claims
- 1. An encoding mask for use in conjunction with an electromagnetic beam of radiation for spatially encoding the beam as the mask is moved through the beam at a constant, predetermined speed to thereby facilitate the locating of an object in space, comprising a surface having a series of adjacent regions defining frames, each of said regions being defined by one or more sets of spaced apart cyclically recurring bands effective to vary a detectable beam parameter, the spacing between adjacent bands of a set being preselected to produce a predetermined beam modulation frequency as the surface is moved through the beam, the adjacent bands of one set of bands within a frame being shifted in position from the adjacent bands of at least one other set of bands within the same frame to thereby spatially modulate the beam at two phases of said frequency, at least, as a frame is moved through the beam.
- 2. In the encoding mask as set out in claim 1 wherein said bands alter the intensity of the radiation passing therethrough relative to the intensity of the radiation passing through the regions between adjacent bands.
- 3. In the encoding mask as set out in claim 1 wherein said bands alter the wavelength of radiation passing therethrough relative to the radiation pass band of the regions between adjacent bands.
- 4. In the encoding mask as set out in claim 1 wherein said bands alter the polarization of radiation passing therethrough relative to the radiation passing through the regions between adjacent bands.
- 5. In the encoding mask as set out in claim 1 wherein said surface is generally rectangularly shaped with a plurality of frames being sequentially positioned along the length of the surface.
- 6. In the encoding mask as set out in claim 1 wherein said surface is curved, said frames being located about the surface circumference, with the different sets of spaced apart radiation transmitting bands being radially disposed within each frame.
- 7. A system for encoding a beam of electromagnetic radiation in a manner whereby the beam cross section is spatially encoded to define resolution elements which are detectable by an object to locate itself within the beam, comprising:
- a source of electromagnetic radiation;
- projection means for producing a beam of radiation in response to radiation from said source; and
- means for spatially modulating said beam by the use of a frequency having at least two fixed, discrete phases so as to convey a sequence of digital codes to produce an array of digital words which resolve positions within the beam into unique discrete locations.
- 8. In the encoding system according to claim 7 wherein said spatial modulation means includes means for phase modulating the beam of radiation in accordance with said digital codes whereby said beam is spatially encoded into resolution elements, each of which is identified by a different one of said digital words.
- 9. In the encoding system according to claim 8 wherein said spatial modulation means includes a plurality of electromagnetic radiation sources and means for phase modulating the radiation intensity of each of said sources in accordance with a digital word to define said spatially separated resolution elements.
- 10. A system for encoding a beam of electromagnetic radiation in a manner whereby the beam cross section is spatially encoded to define resolution elements which are detectable by an object to locate itself within the beam, comprising:
- a source of electromagnetic radiation;
- projection means for producing a beam of radiation in response to radiation from said source; and
- means for spatially modulating said beam in accordance with a digital code, said spatial modulation means including an encoding mask defining at least one frame comprising a plurality of cyclically recurring regions effective to vary a detectable beam parameter, said regions being spaced apart by a distance proportional to a predetermined frequency determined by the rate at which the frame moves through the beam, at least two of said regions in each information frame shifted in position relative to each other, and means for moving said frame of the mask through the beam of radiation at a selected rate to vary the phase of the radiation at said predetermined frequency.
- 11. In the encoding system according to claim 10 wherein said detectable parameter is beam intensity and said regions are bands of light transmitting areas spaced apart by light blocking areas.
- 12. In the encoding system according to claim 10 wherein said spatial modulation means includes two encoding masks for modulating the beam in two orthogonal directions.
- 13. In the encoding system according to claim 10 wherein said encoding mask is a segment of an encoding wheel.
- 14. In the encoding system according to claim 11 wherein said encoding mask includes a plurality of frames, each frame having at least two special sets of light transmitting bands having equal spacing between the bands of all sets, the position of at least one of said sets in each information frame shifted with respect to at least one other set to thereby simultaneously modulate the beam of radiation at two different phases of said frequency as an information frame of the mask is moved through the beam.
- 15. In the encoding system according to claim 14 in which said encoding mask further includes a frame having a single set of light transmitting bands having the same spacing as said special sets, said frame modulating the beam of radiation at a 0.degree. phase of said frequency, said two different modulation phases produced by said special sets being 0.degree. and 180.degree..
- 16. In the encoding system according to claim 15 in which said modulation from said frame is usable by said object as a phase reference.
- 17. In the encoding system according to claim 14 wherein said encoding mask includes N frames plus a reference frame, said frames being provided with sets of light transmitting bands to define 2.sup.N resolution elements.
- 18. In the encoding system according to claim 10 wherein said source of electromagnetic radiation is a source of laser energy, and further comprising optic means for sizing the source radiation to uniformly illuminate at least a portion of a frame of said encoding mask and projection means for relaying the encoded radiation as a radiation beam of preselected dimension and intensity.
- 19. A system for locating an object relative to its position in a beam of electromagnetic radiation and including means for spatially encoding the radiation beam into resolution elements which can be detected by the object to provide it with position information, comprising:
- a source of electromagnetic radiation;
- projection means for producing a beam of radiation which can be received by the object;
- means for spatially modulating said beam by the use of at least two fixed phases of a discrete frequency so as to convey an array of digital words which resolve positions within the beam into unique discrete locations; and
- receiver means carried by said object for detecting said digital words to provide said object with an indication of its position relative to said resolution elements.
- 20. In the system as claimed in claim 19 wherein said receiver means includes detector means responsive to the beam radiation, and decoder means responsive to said detector means for decoding the received digital, phase modulation received by the detector means.
- 21. In the system as claimed in claim 20 wherein said phase modulating means includes an encoding mask having at least one frame for movement through said beam, said frames comprising spaced apart means for simultaneously and cyclically varying a beam characteristic of at least two different phases of said discrete frequency to define at least two resolution elements.
- 22. In the system as claimed in claim 21 in which said encoding mask further has a first frame for varying a beam characteristic at a single phase of said discrete frequency to serve as a reference phase.
Parent Case Info
This is a continuation-in-part of application Ser. No. 7,751, filed Jan. 30, 1979, now U.S. Pat. No. 4,299,360.
US Referenced Citations (10)
Continuation in Parts (1)
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Number |
Date |
Country |
Parent |
7751 |
Jan 1979 |
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