Virtual reality system with an optical position-sensing facility

• US 5,844,674 A
• Filed: 12/20/1996
• Issued: 12/01/1998
• Est. Priority Date: 12/23/1995
• Status: Expired due to Fees

• Current Assignee: Micronas Intermetall GmbH (TDK Corporation)
• Original Assignee: Deutsche ITT Industries GmbH (TDK Corporation)
• Inventors: Sieben, Ulrich
• Primary Examiner(s): Hellner, Mark
• Application Number:
  US08/771,132
• Time in Patent Office: 711 Days
• Field of Search: 359/139.03, 359/141.3, 348/115
• US Class Current: 356/139.03
• CPC Class Codes: G06F 3/012 Head tracking input arrangements
• CPC Class Codes: G06F 3/0304 Detection arrangements using opto-electronic means constructional details of pointing devices not related to the detection arrangement using opto-electronic means G06F3/033; optical digitisers G06F3/042

Abstract

A virtual reality system permanently connected with a device to be worn by a user is disclosed which has an optical position-sensing facility that contains at least one radiation source defining a fixed reference point in space and an optical receiving system permanently connected with the device. The optical receiving system includes three radiation detectors, whose optical axes are parallel to each other. The first radiation detector has a reception pattern which shows a rising/falling sensitivity characteristic in a first angular range. The second radiation detector has a reception pattern which shows a rising/falling sensitivity characteristic in a second angular range. The third radiation detector has a reception pattern which shows a slowly varying sensitivity characteristic within at least the first and second angular ranges.

Claims

1. A virtual reality system permanently connected with a device to be worn by a user, comprising:

an optical position-sensing facility which comprises at least one radiation source defining a fixed reference point in space;

an optical receiving system permanently connected with said device, said optical receiving system comprising at least a first radiation detector, a second radiation detector and a third radiation detector, whose optical axes, a first optical axis, a second optical axis, and a third optical axis respectively, are parallel to each other and, in a basic position, point at the at least one radiation source;

the first radiation detector, has a reception pattern which has, in a first plane defined by the first optical axis, and by a first direction determined by the optical receiving system in a first angular range including the first optical axis, a rising/falling sensitivity characteristic which is essentially monotonic;

the second radiation detector has a reception pattern which has, in a second plane defined by the second optical axis and by a second direction determined by the optical receiving system, in a second angular range including the second optical axis, a rising/falling sensitivity characteristic which is essentially monotonic; and

the third radiation detector has a uniform reception pattern which has, within at least the first and second angular ranges, a sensitivity characteristic which varies slowly in comparison with the sensitivity characteristic of the first or second radiation detector.

2. The virtual reality system in accordance with claim 1, further comprising, in addition to said one radiation source, further radiation sources of a predetermined number which define further fixed reference points, said further radiation sources lying in the same horizontal plane as said one radiation source and essentially forming a circle around the device to be worn by the user and being separated by equal angular distances less than or equal to the first angular range lying in the same plane.

3. The virtual reality system in accordance with claim 1, wherein to sense axial rotations, particularly about the axis formed by the direction of view, the optical position-sensing facility comprises polarization filters, at least one polarized-radiation source, and at least one polarized-radiation detector.

4. The virtual reality system in accordance with claim 2, wherein to sense axial rotations, particularly about the axis formed by the direction of view, the optical position-sensing facility comprises polarization filters, at least one polarized-radiation source, and at least one polarized-radiation detector.

5. The virtual reality system in accordance with claim 3, wherein the output signal of the third radiation detector is a first reference value for the calculation of the axial angle of rotation, and the output signal of the at least one polarized radiation detector is a second reference value for said calculation.

6. The virtual reality system in accordance with claim 4, wherein the output signal of the third radiation detector is a first reference value for the calculation of the axial angle of rotation, and the output signal of the at least one polarized radiation detector is a second reference value for said calculation.

7. The virtual reality system in accordance with claim 5, wherein for the calculation of the axial rotation, the first and second reference values correspond to cosine and sine based trigonometric reference values, respectively, which relate to the polarization directions of a first polarization filter and a second polarization filter.

8. The virtual reality system in accordance with claim 6, wherein for the calculation of the axial rotation, the first and second reference values correspond to cosine and sine based trigonometric reference values, respectively, which relate to the polarization directions of a first polarization filter and a second polarization filter.

9. The virtual reality system in accordance with claim 2, wherein the radiation source and the further radiation sources are activated in a multiplex mode.

10. A virtual reality system permanently connected with a device to be worn by a user, comprising:

an optical position-sensing facility which comprises at least one radiation detector defining a fixed reference point in space;

at least one optical transmitting system permanently connected with said device, said optical transmitting system comprising at least a first radiation source, a second radiation source, and a third radiation source whose optical axes, a first optical axis, a second optical axis, and a third optical axis respectively, are parallel to each other and, in a basic position, point at the at least one radiation detector;

the first radiation source has an intensity pattern which has, in a first plane defined by the first optical axis, and by a first direction determined by the optical transmitting system, in a first angular range including the first optical axis, a rising/falling sensitivity characteristic which is essentially monotonic;

the second radiation source has an intensity pattern which has, in a second plane defined by the second optical axis and by a second direction determined by the optical transmitting system, in a second angular range including the second optical axis, a rising/falling intensity characteristic which is essentially monotonic; and

the third radiation source has a uniform intensity pattern which has, at least within the first and second angular ranges, an intensity characteristic which varies slowly in comparison with the intensity characteristic of the first or second radiation source.

11. The virtual reality system in accordance with claim 10, further comprising, in addition to said one radiation detector, further radiation detectors of a predetermined quantity are provided which define further fixed reference points, said further radiation detectors lying in the same horizontal plane as said one radiation detector and essentially forming a circle around the device to be worn by the user and being separated by equal angular distances less than or equal to the first angular range lying in the same plane.

12. The virtual reality system in accordance with claim 10, wherein to sense axial rotations, particularly about the axis formed by the direction of view the optical position-sensing facility comprises first and second polarization filters, at least one polarized-radiation source, and at least one polarized radiation detector.

13. The virtual reality system in accordance with claim 11, wherein to sense axial rotations, particularly about the axis formed by the direction of view the optical position-sensing facility comprises first and second polarization filters, at least one polarized-radiation source, and at least one polarized radiation detector.

14. The virtual reality system in accordance with claim 12, wherein the output signal of the third radiation source is a first reference value for the calculation of the axial angle of rotation, and the output signal of the at least one polarized radiation detector is a second reference value for said calculation.

15. The virtual reality system in accordance with claim 13, wherein the output signal of the third radiation source is a first reference value for the calculation of the axial angle of rotation, and the output signal of the at least one polarized radiation detector is a second reference value for said calculation.

16. The virtual reality system in accordance with claim 14, wherein for the calculation of the axial rotation, the first and second reference values correspond to cosine and sine dependent trigonometric reference values, respectively, which relate to the polarization directions of a first polarization filter and a second polarization filter.

17. The virtual reality system in accordance with claim 15, wherein for the calculation of the axial rotation, the first and second reference values correspond to cosine and sine dependent trigonometric reference values, respectively, which relate to the polarization directions of a first polarization filter and a second polarization filter.

18. In a position dependent virtual reality system permanently connected with a device worn by a user, a position sensing system comprising:

at least one radiation source defining a fixed reference point in space; and

an optical receiving system coupled with said device, said optical receiving system comprising at least a first radiation detector, a second radiation detector and a third radiation detector, whose optical axes, a first optical axis, a second optical axis, and a third optical axis, respectively, are parallel to each other and, in a basic position, point at the at least one radiation source.

19. The virtual reality system in accordance with claim 18, wherein the first radiation detector, has a reception pattern which has, in a first plane defined by the first optical axis, and by a first direction determined by the optical receiving system in a first angular range including the first optical axis, a rising/falling sensitivity characteristic which is essentially monotonic.

20. The virtual reality system in accordance with claim 19, wherein the second radiation detector has a reception pattern which has, in a second plane defined by the second optical axis and by a second direction determined by the optical receiving system, in a second angular range including the second optical axis, a rising/falling sensitivity characteristic which is essentially monotonic.

21. The virtual reality system in accordance with claim 20, wherein the third radiation detector has a uniform reception pattern which has, within at least the first and second angular ranges, a sensitivity characteristic which varies slowly in comparison with the sensitivity characteristic of the first or second radiation detector.

22. The virtual reality system in accordance with claim 21, further comprising a plurality of further radiation sources defining further fixed reference points, the further radiation sources being disposed in the same horizontal plane as the one radiation source.

23. The virtual reality system in accordance with claim 22, further comprising at least two polarization filters, at least one polarized radiation source, and at least one polarized radiation detector, which enable the position sensing system to sense axial rotations about an axis formed by a predetermined direction of view.

24. The virtual reality system in accordance with claim 23, wherein the output signal from the third radiation detector is a first reference value for calculation of the axial angle of rotation, and the output signal of the at least one polarized radiation detector is a second reference value for the calculation.

25. The virtual reality system in accordance with claim 22, wherein the at least one radiation source and the further radiation sources are activated in a multiplex mode.