Optical input arrangement and method of using same

• US 5,504,501 A
• Filed: 07/18/1994
• Issued: 04/02/1996
• Est. Priority Date: 11/07/1989
• Status: Expired due to Term

• Current Assignee: Straight Signals LLC (Intellectual Ventures LLC)
• Original Assignee: Proxima Corporation (Ask ASA)
• Inventors: Hauck, Lane T., Shapiro, Leonid
• Primary Examiner(s): Hjerpe, Richard
• Assistant Examiner(s): WU, XIAO MIN
• Application Number:
  US08/276,568
• Time in Patent Office: 624 Days
• Field of Search: 345/157, 345/156, 345/158, 345/169, 345/180, 359/142, 359/443, 359/448, 359/449, 359/459, 356/375, 348/734, 348/744, 434/323, 434/324, 434/337, 353/122, 353/28, 353/43, 353/42
• US Class Current: 345/158
• CPC Class Codes: G06F 3/038 Control and interface arrangements therefor, e.g. drivers or device-embedded control circuitry
• CPC Class Codes: G06F 3/0386 for light pen

Abstract

An optical input arrangement and method includes an optical device for sensing a projected image and for detecting the presence of a high intensity optical input signal light by discriminating it from the entire projected image and the ambient light reflecting from a viewing surface. A determination is made as to when the differences in intensity of sequentially measured pixel intensity values of the light reflected from the viewing surface exceeds a positive threshold amount and substantially immediately thereafter decreases more than a negative threshold amount, to facilitate an even more precise discrimination between the input signal image and the overall projected image. An alignment device generates an optical signal for facilitating the alignment of the arrangement to capture the entire image reflecting from the viewing surface.

Claims

1. In an image projection arrangement including projection means for directing a projected image onto a remote viewing surface, light sensing means for detecting all wavelengths of light in the visible spectrum including the reflected projected image and ambient light, and an optical apparatus for generating a video image, a system for controlling the optical apparatus for generating a video image, comprising:

means for generating an optical control image having a predetermined optical wavelength and a given intensity level to modify the projected image;

means interposed between the remote viewing surface and the light sensing means for passing visible light within a narrow predetermined band of optical wavelengths only including the reflected projected image, ambient light and said optical control image;

signal means responsive to the light sensing means for generating an electrical signal indicative of the visible light having said narrow band of wavelengths;

signal modification means responsive to said signal means for determining a black level reference level to help generate a modified electrical signal indicative of the visible light having said narrow band of wavelengths and a peak intensity level substantially equal to the combination of the lowest intensity level of the projected image reflecting from the viewing surface and the highest intensity level of the control image reflecting from the viewing surface;

reference level means responsive to said modified electrical signal for determining a peak video image reference level, and a peak control image reference level and for establishing a reference level between said peak video image reference level and said peak control image reference level;

control means responsive to said electrical signal for generating a control signal indicative of a desired modification of the projected image whenever the electrical signal is greater than said reference level, said electrical signal being further indicative of visible light in said narrow band of wavelengths and having a peak intensity level that is at least greater than the highest intensity level of the protected image reflecting from the viewing surface; and

means for modifying the projected image in response to said control signal.

2. A system according to claim 1, wherein said means for generating an optical control image is laser light generating means.

3. A system according to claim 2, wherein said laser light generating means is light emitting diode means.

4. A system according to claim 3, wherein said light emitting diode means includes:

a light emitting diode; and

switch means for actuating said light emitting diode on and off to produce said control image for projection onto the viewing surface.

5. A system according to claim 1, wherein said means for producing visible light within the narrow band of optical wavelengths includes optical filter means that passes light having only said narrow band of optical wavelengths so that electrical discrimination of said control image is facilitated.

6. A system according to claim 5, wherein said optical means restricts said optical wavelengths to between about 600 nanometers and 740 nanometers.

7. A system according to claim 5, wherein said optical means restricts said optical wavelengths to between about 635 nanometers and 705 nanometers.

8. A system according to claim 5, wherein said optical means restricts said optical wavelengths to between about 660 nanometers and 680 nanometers.

9. A system according to claim 5, wherein said optical means restricts said optical wavelengths to about 670 nanometers.

10. A system according to claim 1, wherein said light sensing means is a camera means.

11. A system according to claim 1, wherein said light sensing means is a charge coupled means.

12. A system according to claim 11, wherein said charge coupled means is a charge coupled device.

13. A system according to claim 1, wherein said means for generating an optical control image includes means for generating an optical locating image for helping to locate said control image at a desired portion of the projected image;

and

wherein said locating image has an intensity level less than said predetermined intensity level so that said locating image can be distinguished from said control image.

14. A method for controlling an optical apparatus modifying a projected image, comprising:

generating an optical control image having a predetermined optical wavelength and a given intensity level to help modify the projected image;

producing in response to light reflecting from a remote viewing surface, visible light within a narrow predetermined band of optical wavelengths including light indicative of the projected image, ambient light, and light from said optical control image;

generating an electrical signal indicative of the visible light having said narrow band of wavelengths;

determining a black level reference level to help generate a modified electrical signal indicative of the visible light having said narrow band of wavelengths and a peak intensity level substantially equal to the combination of the lowest intensity level of the projected image reflecting from the viewing surface and the highest intensity level of the control image reflecting from the viewing surface;

determining a peak video image reference level, and a peak control image reference level;

establishing a reference level between said peak video image reference level and said peak control image reference level;

generating a control signal indicative of a desired modification of the projected image whenever the electrical signal is greater than said reference level, said electrical signal being further indicative of visible light in said narrow band of wavelengths and having a peak intensity level that is at least greater than the highest intensity level of the projected image reflecting from the viewing surface; and

modifying the projected image in response to said control signal.

15. A method according to claim 14, wherein the step of generating includes:

generating an optical locating image for helping to locate said control image at a desired portion of the projected image; and

wherein said locating image has an intensity level less than said predetermined intensity level so that said locating image can be distinguished from said control image.

16. A calibration method for an optical input device for a display apparatus controlled by a control light having optical wavelengths in only a narrow band range, comprising:

using the display apparatus to project a calibration video image onto a remote viewing surface;

detecting a predetermined narrow band of optical wavelengths of light reflected from the viewing surface;

determining the value of the maximum video intensity of the reflected wavelengths of light;

storing the maximum intensity value thereof;

establishing a reference level value at a level substantially greater than the stored maximum intensity value and substantially less than the combination of the value of the maximum video intensity and a maximum value of control light directed onto and reflecting from the video image;

said maximum video intensity value being the maximum intensity level value of only that portion of light reflecting from a remote viewing surface indicative of a projected video image having wavelengths in only a narrow band range;

said maximum control light value being the combination of the minimum intensity level value of only that portion of light reflecting from said remote viewing surface indicative of said projected video image having wavelengths in only the narrow band range and the maximum control light intensity value having wavelengths in only said narrow band range, where the control light is reflecting from the last mentioned portion of said projected video image; and

generating a control signal whenever the value of said detection signal is greater than said reference level value, said control signal indicative of at least a detected video image coordinate location for helping to control the display.

17. A method of controlling a display according to claim 16, wherein the step of establishing includes:

generating a bright video image and projecting it onto a remote viewing surface, wherein the projected video image reflecting from said remote surface has a maximum intensity level and a minimum intensity level;

detecting light reflecting from the remote surface having wavelengths in only a narrow band range, said light including ambient light having all visible wavelengths;

generating an electrical signal in response to the step of detecting, said electrical signal being indicative of light reflecting from the remote surface and having wavelengths in only said narrow band range;

determining that portion of the electrical signal indicative of only that portion of the projected video image having wavelengths in said narrow band range;

determining said peak video image reference level indicative of the maximum intensity level of only that portion of the projected image with wavelength in only said narrow band range.

18. A method according to claim 17, wherein the step of establishing further includes:

using a control light having wavelengths in only said narrow band range;

directing said control light onto that portion of the projected video image having said minimum intensity level;

repeating the step of detecting;

generating another electrical signal in response to the last mentioned step of detecting, said another electrical signal being indicative of light in only said narrow band range; and

determining in response to said another electrical signal said peak control image reference level indicative of the combination of the minimum intensity level of the projected video image with wavelengths in only said narrow band range and the maximum intensity level of the control light having wavelengths in only said narrow band range.

19. A method of controlling a display according to claim 18, wherein the step of generating a control signal includes repeating the step of detecting.

20. A system for calibrating an optical input device for a display apparatus controlled by a control light having optical wavelengths in only a narrow band range, comprising:

means for detecting a predetermined narrow band of optical wavelengths of light reflected from the viewing surface;

means for determining the value of the maximum video intensity level of the reflected wavelengths of light;

means for storing the maximum intensity thereof;

means for establishing a reference level value, at a level substantially greater than the stored maximum intensity value and substantially less than the combination of the value of the maximum video intensity value and a maximum value of control light directed onto and reflecting from the video image;

said maximum video intensity value being the maximum intensity level value of only that portion of light reflecting from a remote viewing surface indicative of a projected video image having wavelengths in only a narrow band range;

said maximum control light value being the combination of the minimum intensity level value of only that portion of light reflecting from said remote viewing surface indicative of said projected video image having wavelengths in only the narrow band range and the maximum control light intensity value having wavelengths in only the narrow band range, where the control light is reflecting from the last mentioned portion of said projected video image; and

means for generating a control signal whenever the value of said detection signal is greater than said reference level value, said control signal indicative of at least a detected video image coordinate location for helping to control the display.

21. An auxiliary optical command arrangement for a liquid crystal display system for projecting an image onto a surface, comprising:

optical sensing means for receiving incoming light indicative of a reflected projected image, a reflected auxiliary command image having a narrow band of optical wavelengths, and extraneous light including reflected and direct ambient light of different intensities and optical wavelengths;

an auxiliary light command device for generating an auxiliary light command image having a narrow wavelength band to help discriminate the command image from all other light incident upon said optical sensing means;

optical attenuation means for filtering the incoming light being received by said optical sensing means to pass only said narrow band of optical wavelengths to facilitate the detection of said auxiliary command image by said optical sensing means so that said sensing means can detect received light in said narrow band;

said optical sensing means generating an electrical output signal indicative of light only having wavelengths substantially within said narrow band of optical wavelengths;

differential means responsive to said output signal for determining a differential intensity value of the light sensed by said optical sensing means; and

discrimination means for detecting when said differential intensity value exceeds a positive threshold amount and substantially immediately thereafter decreases more than a negative threshold amount to discriminate against reflected projected image light and extraneous light so that only auxiliary light command images can be detected.

22. An auxiliary optical command arrangement according to claim 21, wherein said optical attenuation means restricts said optical wavelengths to between about 600 nanometers and 740 nanometers.

23. An auxiliary optical command arrangement according to claim 21, wherein said optical attenuation means restricts said optical wavelengths to between about 635 nanometers and 705 nanometers.

24. An auxiliary optical command arrangement according to claim 21, wherein said optical attenuation means restricts said optical wavelengths to between about 660 nanometers and 680 nanometers.

25. An auxiliary optical command arrangement, according to claim 21, wherein said auxiliary command image has a wavelength band between about 665 nanometers and 675 nanometers.

26. An auxiliary optical command arrangement, according to claim 21, wherein said auxiliary command image has a wavelength band centered at about 670 nanometers.

27. An auxiliary optical arrangement according to claim 21, further comprising:

mounting means connected to said sensing means for supporting it movably to enable it to be adjusted positionally relative to a viewing area on the surface so that said sensing means can be aligned with the viewing area;

a light source mounted to said optical sensing means for projecting an alignment image onto the viewing area to facilitate adjustment of said optical sensing means to an aligned position;

electrical switch means coupled to said light source for activating it to project the alignment image generally toward the viewing area so that said sensing means and said light source can be moved adjustably by employing said mounting means until the alignment image is positioned generally at a central portion of the viewing area;

whereby said optical sensing means is properly aligned with the viewing area to sense optically the entire projected image.

28. An auxiliary optical arrangement according to claim 27, wherein said optical attenuation means includes lens means having an optical center to direct incoming light.

29. An auxiliary optical arrangement according to claim 28, wherein said light source is mounted substantially on a horizontal optical axis of said lens means and in close proximity to said optical center.

30. An auxiliary optical arrangement according to claim 28, wherein said light source is a light emitting diode.

31. An auxiliary optical arrangement according to claim 29, wherein said light source is a laser.

32. An optical input arrangement according to claim 21, wherein said optical sensing means includes a video camera.

33. An auxiliary optical command arrangement according to claim 21, wherein said discrimination means includes a digital signal processor.

34. An auxiliary optical command arrangement according to claim 27, wherein said light source is a laser light source having a narrow band of optical wavelengths;

and

wherein said alignment image is an auxiliary command image.

35. A method of using an auxiliary optical command arrangement for controlling a liquid crystal display system for projecting an image onto a surface, comprising:

receiving incoming light indicative of a reflected projected image, a reflected auxiliary command image having a narrow band of optical wavelengths, and extraneous light including reflected and direct ambient light of different intensities and optical wavelengths;

directing an auxiliary light command image having a narrow wavelength band onto the surface and the projected image thereon to help discriminate the command image from all other light;

optically filtering the incoming light being received to pass only said narrow band of optical wavelengths to facilitate the detection of said auxiliary command image;

generating an electrical output signal indicative of light only having wavelengths substantially within said narrow band of optical wavelengths;

detecting when an intensity value exceeds a positive threshold amount and substantially immediately thereafter decreases more than a negative threshold amount to discriminate against reflected projected image light and extraneous light so that only auxiliary light command images can be detected.

36. A method of using an auxiliary optical command arrangement for controlling a liquid crystal display system for projecting an image onto a surface, according to claim 35 further comprising:

using optical sensing means;

sensing optically a projected image, said image having an associated viewing area on the surface to generate electrical command signals for controlling the display system;

using a light source for producing an alignment image;

projecting said alignment image onto the viewing area to facilitate adjustment of said optical sensing means to an aligned position;

activating said light source to project the alignment image generally toward the viewing area so that said sensing means and said light source can be moved adjustably until the alignment image is positioned generally at a central portion of the viewing area;

whereby said optical sensing means is properly aligned with the viewing area to sense optically the entire projected image.

37. A system for calibrating an optical input device for a display apparatus controlled by a control light having optical wavelength in only a narrow band range, said control light for reflecting from a viewing surface, comprising:

means for filtering light reflecting from the viewing surface to enable only a predetermined narrow band of optical wavelengths of light to be detected, said light reflecting from the viewing surface including light from the projected video image, the control light and background light;

means for generating a video signal indicative of the combination of the filtered projected video image and the filtered background light to facilitate discriminating accurately the projected video image from the background light reflecting from the viewing surface, said video signal having a minimum value and a maximum value;

means for determining the minimum value of said video signal to facilitate the elimination of a portion of said video signal indicative of the background light;

means for storing the determined minimum value to facilitate modifying said video signal thereafter for calibration purposes;

means for decreasing said video signal by the stored minimum value to generate a modified video signal indicative of the projected video image only, said modified video signal having a minimum value and a maximum value; and

means for determining a reference level signal greater than said modified video signal to distinguish a signal indicative of an auxiliary light image from said modified video signal to help the optical input system detect the control image on the viewing surface.