Wave receiving device and method of determining wave reception

• US 7,880,721 B2
• Filed: 02/10/2006
• Issued: 02/01/2011
• Est. Priority Date: 02/25/2005
• Status: Active Grant

• Current Assignee: NEC Display Solutions, Ltd. (NEC Corporation)
• Original Assignee: NEC Viewtechnology, Ltd.
• Inventors: Inamoto, Kenji, Kobayashi, Hiroyuki, Murayama, Syuuji, Suzuki, Kenji
• Primary Examiner(s): Eisen; Alexander
• Assistant Examiner(s): LAM, NELSON C
• Application Number:
  US11/350,926
• Publication Number:
  US 20060195274A1
• Time in Patent Office: 1,817 Days
• Field of Search: 345173-179, 702/39
• US Class Current: 345/157
• CPC Class Codes: G01S 11/16 using difference in transit time between electrical and acoustic signals

Abstract

An ultrasonic receiver receives an ultrasonic signal having a period in which an amplitude thereof progressively increases as time elapses. A pattern matching unit determines whether a comparative pattern, which is generated as a result of comparison between the respective maximum amplitude values of a plurality of successive waves of said wave signal and a threshold value set by a threshold setting unit, matches a reference pattern or not during the period of the ultrasonic signal. The pattern matching unit determines that the ultrasonic receiver has successfully received the ultrasonic signal if the comparative pattern matches the reference pattern.

Claims

1. A wave receiving device for receiving a wave signal having a period in which an amplitude thereof progressively increases as time elapses, the wave receiving device comprising:

a receiver for receiving the wave signal; and

a determining unit for determining that said receiver has successfully received said wave signal based on a comparative pattern which is generated as a result of a comparison between respective amplitude values of a plurality of successive waves of said wave signal received by said receiver and a threshold value,

wherein said determining unit comprises;

a shift register for successively holding the amplitude values of the successive waves of said wave signal, said shift register comprising a plurality of series-connected registers;

a pattern matching unit for generating said comparative pattern based on the comparison between the amplitude values held by said shift register and said threshold value, and determining that said receiver has successfully received said wave signal when the generated comparative pattern matches said reference pattern; and

a dynamic threshold setting unit for resetting said threshold value between the amplitude values, held bid shift register, of one of said successive waves and the amplitude value, held by said shift register, of a next one of said successive waves, when said comparative pattern does not match said reference pattern.

2. The wave receiving device according to claim 1, wherein said one of the successive waves comprises a second one of the successive waves, which is received by said receiver during said period.

3. The wave receiving device according to claim 1, wherein said wave signal comprises a sound signal,

wherein the wave signal having a period in which the amplitude thereof progressively increases as time elapses, as compared from one cycle to a next cycle of the wave signal, and

wherein the amplitude values are held by a memory unit for comparing with the threshold, the memory unit successively holding the amplitude values of the successive waves of said wave signal, the memory comprising a plurality of series-connected memory units holding each of the amplitude values according to a timing signal from a zero crossing detector for detecting a zero crossing point of the wave signal from a negative level to a positive level.

4. The wave receiving device according to claim 1, wherein said wave signal comprises an ultrasonic signal, and

wherein the wave signal having a period in which the peak amplitude thereof progressively increases as time elapses, and

wherein an amplitude value is according to a positive peak of the wave signal received from a positive peak hold circuit and a negative peak of the wave signal received from a negative peak hold circuit.

5. The wave receiving device according to claim 1, further comprising:

an electromagnetic signal receiver for receiving an electromagnetic signal which is transmitted simultaneously with said wave signal from an external transmitting device which transmits said wave signal; and

a time measuring unit for measuring a period of time after said electromagnetic signal receiver has received said electromagnetic signal until said determining unit determines that said receiver has successfully received said wave signal.

6. The wave receiving device according to claim 5, wherein said electromagnetic signal comprises an infrared signal.

7. The electronic presentation system comprising:

a projector including a plurality of wave receiving devices, each of the wave receiving devices according to claim 5; and

a pointing device for transmitting the wave signal and the electromagnetic signal;

wherein each of said wave receiving devices measures a period of time until the wave signal transmitted from said pointing device arrives at the wave receiving device based on times at which the wave receiving device has received said wave signal and said electromagnetic signal.

8. The electronic presentation system according to claim 7, wherein said electromagnetic signal comprises an infrared signal.

9. A wave receiving device for receiving a wave signal having a period in which an amplitude thereof progressively increases as time elapses, the wave receiving device comprising:

a receiver for receiving the wave signal; and

a determining unit for determining, that said receiver has successfully received said wave signal based on a result of a comparison between a comparative pattern and a reference pattern, said comparative pattern being generated as a result of comparison between respective amplitude values of a plurality of successive waves of said wave signal received by said receiver and a threshold value,

wherein said determining unit comprises;

a shift register for successively holding the amplitude values of the successive waves of said wave signal, said shift register comprising a plurality of series-connected register;

a pattern matching unit for generating said comparative pattern based on the comparison between the amplitude values held by said shift register and said threshold value, and determining that said receiver has successfully received said wave signal when the generated comparative pattern matches said reference pattern; and

a dynamic threshold setting unit for resetting said threshold value between the amplitude values, by said shift register, of one of said successive waves and the amplitude value, held by said shift register, of a next one of said successive waves when said comparative pattern does not match said reference pattern.

10. The wave receiving device according to claim 9, wherein said wave signal comprises a sound signal.

11. The wave receiving device according to claim 9, wherein said wave signal comprises an ultrasonic signal.

12. The wave receiving device according to claim 9, further comprising:

an electromagnetic signal receiver for receiving an electromagnetic signal which is transmitted simultaneously with said wave signal from an external transmitting device which transmits said wave signal; and

a time measuring unit for measuring a period of time aider said electromagnetic signal receiver has received said electromagnetic signal until said determining unit determines that said receiver has successfully received said wave signal.

13. The wave receiving device according to claim 12, wherein said electromagnetic signal comprises an infrared signal.

14. The electronic presentation system comprising:

a projector including a plurality of wave receiving devices with each of the wave receiving devices according to claim 12; and

a pointing device for transmitting the wave signal and the electromagnetic signal;

wherein each of said wave receiving devices measures a period of time until the wave signal transmitted from said pointing device arrives at the wave receiving device based on times at which the wave receiving device has received said wave signal and said electromagnetic signal.

15. The electronic presentation system according to claim 14, wherein said electromagnetic signal comprises an infrared signal.

16. A wave receiving device for receiving a wave signal having a period in which an amplitude thereof progressively increases as time elapses as compared from one cycle to a next cycle of the wave signal, the wave receiving device comprising:

a receiver for receiving the wave signal; and

a determining unit for determining whether at least a portion of a comparative pattern matches a reference pattern, said comparative pattern being generated as a result of comparison between respective amplitude values of a plurality of successive waves of said wave signal received by said receiver and a threshold value, and determining that said receiver has successfully received said wave signal when the at least the portion of said comparative pattern matches said reference pattern,

wherein said determining unit comprises;

a shift register for successively holding the amplitude values of the successive waves of said wave signal said shift register comprising a plurality of series-connected registers;

a pattern matching unit for generating said comparative pattern based on the comparison between the amplitude values held by said shift register and said threshold value, and determining that said receiver has successfully received said wave signal when the generated comparative pattern matches said reference pattern; and

a dynamic threshold setting unit for resetting said threshold value between the amplitude values, held by said shift register, of one of said successive waves and the amplitude value held by id shift register, a next one of said successive, when said comparative pattern does not match said reference pattern.

17. The wave receiving device according to claim 16, further comprising:

an inverting addition processor for adding an original signal which is inverted from the wave signal received and output by said receiver and a signal which is delayed a half phase or one phase from said wave signal to each other;

producing a sum signal, and supplying said sum signal to said determining unit.

18. The wave receiving device according to claim 17, wherein said inverting addition processor and said determining unit comprise digital circuits, respectively.

19. The wave receiving device according to claim 16, wherein said wave signal comprises a sound signal.

20. The wave receiving device according to claim 16, wherein said wave signal comprises an ultrasonic signal.

21. The wave receiving device according to claim 16, further comprising:

an electromagnetic signal receiver for receiving an electromagnetic signal which is transmitted approximately simultaneous with said wave signal from an external transmitting device which transmits said wave signal; and

a time measuring unit for measuring a period of time after said electromagnetic signal receiver has received said electromagnetic signal until said determining unit determines that said receiver has successfully received said wave signal.

22. The wave receiving device according to claim 21, wherein said electromagnetic signal comprises an infrared signal.

23. The electronic presentation system comprising:

a projector including a plurality of wave receiving devices, and each one of the wave receiving devices according to claim 21; and

a pointing device for transmitting the wave signal and the electromagnetic signal;

wherein each of said wave receiving devices measures a period of time until the wave signal transmitted from said pointing device arrives at the wave receiving device based on times at which the wave receiving device has received said wave signal and said electromagnetic signal.

24. The electronic presentation system according to claim 23, wherein said electromagnetic signal comprises an infrared signal.

25. A method of determining wave reception, the method comprising:

receiving a wave signal including a period in which an amplitude thereof progressively increases as time elapses as compared from one cycle to a next cycle of the wave signal; and

determining that said wave signal has successfully been received based on a comparative pattern which is generated as a result of comparison between respective amplitude values of a plurality of successive waves of said wave signal which is received and a threshold value,

wherein said determining comprises;

successively holding, by a shift register, the amplitude values of the successive waves of said wave signal, said shift register comprising a plurality of series-connected registers;

generating, by a pattern matching unit, said comparative Pattern based on the comparison between the amplitude values held by said shift register and said threshold value, and determining that said receiver has successfully received said wave signal when the generated comparative pattern matches said reference pattern; and

resetting, by a dynamic threshold setting unit, said threshold value between the amplitude values, held by said shift register, of one of said successive waves and the amplitude value, held by said shift register, of a next one of said successive waves, when said comparative pattern does not match said reference pattern.

26. The method according to claim 25, wherein said wave signal comprises a sound signal, and determining whether the comparative pattern correlates with a reference pattern comprises determining whether the comparative pattern matches the reference pattern.

27. The method according to claim 25, wherein said wave signal comprises an ultrasonic signal.

28. A method of determining wave reception, comprising:

receiving a wave signal having a period in which a peak amplitude thereof progressively increases as time elapses;

comparing a comparative pattern and a reference pattern with each other, said comparative pattern being generated as a result of comparison between respective amplitude values of a plurality of successive waves of said wave signal which is received and a threshold value,

wherein said comparing comprises;

successively holding the amplitude values of the successive waves of said wave signal, said shift register comprising a plurality of series-connected registers; and

generating said comparative pattern based on the comparison between the amplitude values held by said shift register and said threshold value;

determining that said wave signal has successfully been received based on a result of the comparing,

wherein said determining that said receiver has successfully received said wave signal comprises when the generated comparative pattern matches said reference pattern; and

resetting said threshold value between the amplitude values, held by said shift register, of one of said successive waves and the amplitude value, held by said shift register, of a next one of said successive waves, when said comparative pattern does not match said reference pattern.

29. The method according to claim 28, wherein said wave signal comprises a sound signal.

30. The method according to claim 28, wherein said wave signal comprises an ultrasonic signal.

31. A method of determining wave reception, the method comprising:

receiving a wave signal including a period in which an amplitude thereof progressively increases as time elapses;

determining whether a comparative pattern correlates with a reference pattern or not, said comparative pattern being generated as a result of comparison between respective amplitude values of a plurality of successive waves of said wave signal which is received and a threshold value;

determining that said wave signal has successfully been received when said comparative pattern correlates with said reference pattern;

successively holding the amplitude values of the successive waves of said wave signal in a shift register comprising a plurality of series-connected registers;

generating said comparative pattern based on a comparison between the amplitude values held by said shift register and said threshold value; and

resetting said threshold value between the amplitude value, held by said shift register, of one of said successive waves and the amplitude value, held by said shift register, of a next one of said successive waves, when said comparative pattern does not match said reference pattern.

32. The method according to claim 31, wherein said one of the successive waves comprises a second one of the successive waves which is received during said period.

33. The method according to claim 31, wherein said wave signal comprises a sound signal.

34. The method according to claim 31, wherein said wave signal comprises an ultrasonic signal.