Device and method for cursor motion control calibration and object selection

• US 6,791,531 B1
• Filed: 06/07/2000
• Issued: 09/14/2004
• Est. Priority Date: 06/07/1999
• Status: Expired due to Fees

• Current Assignee: Dot On, Inc.
• Original Assignee: Dot On, Inc.
• Inventors: Johnston, Richard S., Hubbard, Steven S., Melville, Charles D.
• Primary Examiner(s): CHOW, DOON Y
• Application Number:
  US09/590,658
• Time in Patent Office: 1,560 Days
• Field of Search: 345/156, 345/157, 345/158, 345/168, 345/173, 345/174, 345/175, 345/179, 178/18-1-, 341/22, 250/221
• US Class Current: 345/157
• CPC Class Codes: G01J 3/433 Modulation spectrometry; Derivative spectrometry
• 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 device and method for cursor motion control, calibration of the motion control, and object selection and computer command input.

Claims

1. An optical tracking device comprising:

an optical sensor comprising a two-dimensional array of photosensitive pixels;

an imaging lens in focused relationship with the optical sensor;

a circuit for distinguishing a centroid of an optical image having an intensity above a threshold intensity, the distinguishing circuit being electrically coupled to convert the centroid of an optical image formed on the optical sensor and having an intensity above the threshold intensity into electrical video interface signals suitable for controlling the position of a cursor on a computer-controlled display as a function of the position of the centroid of the image relative to the optical sensor; and

a clicking function implemented in software for operation on a processor, the clicking function generating a signal imitating a mouse click signal in response to a change in the quantity of images having an intensity above the threshold intensity.

2. The optical tracking device recited in claim 1, wherein one or more objects forming the image on the optical sensor comprise one or more digits of a user of the device positioned within the field of view of the imaging lens.

3. The optical tracking device recited in claim 2, further comprising an electromagnetic radiation source fixed in close proximity to the imaging lens and illuminating at least a portion of the field of view of the imaging lens, and

wherein the one or more objects forming the image on the optical sensor are illuminated by the electromagnetic radiation.

4. The optical tracking device recited in claim 3, further comprising a reflector objects forming the image on the optical sensor.

5. The optical tracking device recited in claim 4, wherein the reflector object further comprises a retroreflector.

6. The optical tracking device recited in claim 3, wherein the imaging lens further comprises a single element aspheric camera lens.

7. The optical tracking device recited in claim 6, wherein the imaging lens further comprises a pin hole aperture in close proximity thereto.

8. The optical tracking device recited in claim 1, wherein the change in the quantity of images having an intensity above the threshold intensity further comprises the intensity of the control object image being less than the threshold intensity during a predetermined term and rising again above the threshold.

9. The optical tracking device recited in claim 1, wherein the change in the quantity of images having an intensity above the threshold intensity further comprises the momentary appearance of one or more additional object images having an intensity above the threshold in a position relative to the control object image.

10. The optical tracking device recited in claim 1, further comprising a calibration sequence function implemented in software for operation on a processor, the calibration sequence function determining a current position of the control object relative to the array of pixels of the optical sensor and mapping the pixel containing the centroid of the control object image to a pixel of the display screen.

11. The optical tracking device recited in claim 10, wherein the calibration sequence function maps the centroid of the control object image to a pixel located essentially at the center of the display screen.

12. The optical tracking device recited in claim 11, wherein the calibration sequence function further defines a relationship between the amount of spatial movement of the control object relative to the optical sensor and the cursor motion on the display screen.

13. An optical tracking device comprising:

an optical sensor comprising a two-dimensional array of photosensitive pixels;

an imaging lens in focused relationship with the optical sensor;

a circuit for distinguishing a centroid of an optical image having an intensity above a threshold intensity, the distinguishing circuit comprising;

signal thresholds for distinguishing images having an intensity above the threshold intensity,

circuitry for determining connectivity between the pixels determined to have an intensity above the threshold intensity and for determining which of the pixels having an intensity above the threshold intensity are further connected to form an object image,

circuitry for determining a centroid of each object image, and

circuitry for generating output signals representative of the position of the centroid of each object image relative to the array of photosensitive pixels of the optical sensor, and

wherein one or more objects forming the image on the optical sensor comprise one or more digits of a user of the device positioned within the field of view of the imaging lens,

the distinguishing circuit being electrically coupled to convert the centroid of an optical image formed on the optical sensor and having an intensity above the threshold intensity into electrical video interface signals suitable for controlling the position of a cursor on a computer-controlled display as a function of the position of the centroid of the image relative to the optical sensor;

a signal processing function implemented in software for operation on a processor, the signal processing function coupled to receive the output signals representative of the position of the centroid of each object image relative to the array of photosensitive pixels of the optical sensor and determine one control object image among one or more of the object images by distinguishing one or more candidate control object images from one or more other object images as a function of the output of one or more elimination algorithms;

a cursor motion control function implemented in software for operation on a processor, the cursor motion control function responsive to an output signal of the signal processing function representative of the position of the centroid of the control object image relative to the array of photosensitive pixels of the optical sensor for controlling a position of a cursor relative to a display screen; and

a clicking function implemented in software for operation on a processor, the clicking function generating a signal imitating a mouse click signal responsively to a change in the image, the change in the image comprising a change in the quantity of images having an intensity above the threshold intensity.

14. The optical tracking device recited in claim 13, wherein determining one control object image among one or more of the object images further comprises determining the control object image as a function of the physical arrangement of the one or more user digits relative to the field of view of the imaging lens.

16. The optical tracking device recited in claim 13, wherein the change in the quantity of images having an intensity above the threshold intensity further comprises the intensity of the control object image being less than the threshold intensity during a predetermined term and rising again above the threshold.

17. The optical tracking device recited in claim 16, wherein the intensity of the control object image being less than the threshold intensity during a predetermined term and rising again above the threshold further comprises the control object image being in essentially the same position relative to the optical sensor upon rising again above the threshold after the predetermined term as before being less than the threshold intensity.

18. The optical tracking device recited in claim 13, wherein the change in the quantity of images having an intensity above the threshold intensity further comprises the momentary appearance of one or more additional object images having an intensity above the threshold in a position relative to the control object image.

19. The optical tracking device recited in claim 13, further comprising a calibration sequence function implemented in software for operation on a processor, the calibration sequence function determining a current position of the control object relative to the array of pixels of the optical sensor and mapping the pixel containing the centroid of the control object image to a pixel of the display screen.

20. The optical tracking device recited in claim 19, wherein the calibration sequence function maps the centroid of the control object image to a pixel located essentially at the center of the display screen.

21. The optical tracking device recited in claim 20, wherein the calibration sequence function further defines a relationship between the amount of spatial movement of the control object relative to the optical sensor and the cursor motion on the display screen.

22. The optical tracking device recited in claim 21, wherein the relationship between the amount of spatial movement of the control object relative to the optical sensor and the cursor motion on the display screen is defined by a default setting in the implementation software.

23. The optical tracking device recited in claim 21, wherein the calibration sequence function is further responsive to an input signal indicating an instant at which to determine the current position of the control object relative to the optical sensor.

24. The optical tracking device recited in claim 13, further comprising a cursor control object positioned within a field of view of the imaging lens, the cursor control object comprising:

a housing,

a source of electromagnetic radiation positioned within the housing

a power supply, and

a switch for coupling the power supply to the radiation source.

25. The optical tracking device recited in claim 13, further comprising an electromagnetic radiation source fixed in close proximity to the imaging lens and illuminating at least a portion of the field of view of the imaging lens, and

wherein the one or more objects forming the image on the optical sensor are illuminated by the electromagnetic radiation.

26. The optical tracking device recited in claim 25, further comprising a reflector objects forming the image on the optical sensor.

27. The optical tracking device recited in claim 26, wherein the reflector object further comprises a retroreflector.

28. The optical tracking device recited in claim 25, wherein the imaging lens further comprises a single element aspheric camera lens.

29. The optical tracking device recited in claim 28, wherein the imaging lens further comprises a pin hole aperture in close proximity thereto.

15. The optical tracking device recited in claim 15, wherein determining the control object image as a function of the physical arrangement of the one or more user digits relative to the field of view of the imaging lens further comprises identifying one of the object images appearing closest to an edge of the optical sensor.

30. An optical tracking device comprising:

an optical sensor comprising a two-dimensional array of photosensitive pixels,

an imaging lens in focused relationship with the optical sensor, and

a circuit for distinguishing a centroid of an optical image having an intensity above a threshold intensity, the distinguishing circuit being electrically coupled to convert the centroid of an optical image formed on the optical sensor by an electromagnetic radiation source positioned within the field of view of and remotely from the imaging lens and having an intensity above the threshold intensity into electrical video interface signals suitable for controlling the position of a cursor on a computer-controlled display as a function of the position of the centroid of the image relative to the optical sensor, the distinguishing circuit comprising circuitry for determining an object image formed by one or more the pixels having an intensity above the threshold intensity;

a centering function implemented in software for operation on a processor, the centering function determining a current position of the object image relative to the array of pixels of the optical sensor and mapping the pixel containing a centroid of the object image to a pixel at the approximate center of the display screen;

a cursor motion control function implemented in software for operation on a processor,the cursor motion control function responsive to an output signal of the centering function representative of the position of the centroid of the object image relative to the array of photosensitive pixels of the optical sensor for controlling a position of a cursor relative to the display screen;

a clicking function implemented in software for operation on a processor, the clicking function generating a signal imitating a mouse click signal responsively to a reduction in the intensity of the object image.

31. An optical device for tracking a remote object, the device comprising:

an optical sensor formed of a plurality of photosensitive pixels arraigned in a two-dimensional array;

an infrared radiation source essentially collocated with the imaging lens and directing infrared radiation into at least a portion of the field of view of the imaging lens;

an imaging lens arranged to image onto the optical sensor a cursor control object comprising a portion of a digit of the hand of a user of the device, the digit including a reflection augmenting device positioned within the field of view and the depth of field of the imaging lens, the cursor control object illuminated by the infrared radiation and having an image intensity above a minimum threshold intensity wherein only an image formed by infrared radiation reflected from the illuminated cursor control object has an intensity in excess of the minimum threshold intensity, and the imaging lens imaging infrared radiation reflected from the illuminated cursor control object;

an interface circuit coupled to the optical sensor for;

distinguishing a centroid of the cursor control object image,

determining a position of the centroid of the cursor control object image relative to the two-dimensional array of pixels, and

producing cursor control signals suitable for controlling the position of a cursor on a computer-controlled display as a function of the centroid of the control object image position information,

the interface circuit having one or more filters implementing signal thresholds for distinguishing object images that have an intensity above a threshold intensity, the one or more filters comprising;

circuitry implementing a function for determining connectivity between different ones of the pixels that are determined to have an intensity above the threshold intensity,

circuitry implementing a function for determining which of the pixels having an intensity above the threshold intensity are further connected to others of the pixels to form an object image

circuitry implementing a function for determining a centroid of each object image, and

circuitry implementing a function for generating output signals representative of the position of the centroid of each object image relative to the optical sensor; and

a clicking function implemented in software for operation on a processor coupled to receive the cursor control signals, the clicking function generating a signal imitating a mouse click signal responsively to a momentary change in the quantity of object images having an intensity in excess of the minimum threshold intensity.

32. The optical device recited in claim 31, further comprising a signal processing function implemented in software for operation on a processor, the signal processing function coupled to receive the output signals representative of the position of the centroid of each object image relative to the array of photosensitive pixels of the optical sensor and determining one control object image among one or more of the object images.

33. The optical device recited in claim 32, wherein determining one control object image among one or more of the object images further comprises determining the control object image as a function of the physical arrangement relative to the field of view of the imaging lens of the one or more user digits including a reflection augmenting device.

34. The optical device recited in claim 33, wherein determining the control object image as a function of the physical arrangement of the one or more user digits relative to the field of view of the imaging lens further comprises identifying one of the object images appearing closest to an edge of the optical sensor.

35. The optical tracking device recited in claim 31, wherein the reflection augmenting device further comprises a device formed of a retroreflective material.

36. The optical tracking device recited in claim 31, wherein the momentary change in the quantity of object images having an intensity in excess of the minimum threshold intensity further comprises a momentary reduction in the intensity of the control object image to less than the minimum threshold intensity before a resumption of intensity above the threshold while the control object image retains an essentially constant position relative to the optical sensor.

37. A device for remote control of a display screen cursor, the device comprising:

a) a camera comprising;

i) a solid state image sensor comprising a two-dimensional array of light sensitive memory cells arranged in a plurality of rows and columns, each cell being accessible for reading, the output upon reading any cell being a function of the light intensity thereupon relative to a threshold,

ii) a lens fixed relative to the image sensor focusing a light image of a reflective cursor control object on the cells thereof,

iii) an interface circuit coupled to the image sensor producing electronic video signals suitable for controlling the position of a cursor on a computer-controlled display as a function of the position relative to the image sensor a centroid of a control object image having an intensity above the threshold;

b) one or more electromagnetic infrared radiation sources essentially collocated with the lens and illuminating objects positioned within the field of view of the lens;

c) a hand-operable reflective cursor control object formed of a retroreflective material and positionable within the field of view of the lens and reflecting illumination from the one or more electromagnetic radiation sources toward the lens; and

d) a clicking function implemented in software for operation on a processor, the clicking function coupled to receive an output of the camera and generating an output signal imitating a mouse click signal responsively to a change in the cursor control object image, the change in the cursor control object image further comprising a change in the intensity of the cursor control object image to a level less than the threshold intensity level during a term and a subsequent change in the intensity level of the cursor control object image to a level greater than the threshold intensity level at substantially the same position relative to the optical sensor.

38. A method for tracking a remote object to control the position of a cursor on a computer-controlled display as a function of the position of a control object, the method comprising:

illuminating a hand-operable reflective cursor control object with one or more electromagnetic radiation sources;

reflecting illumination from the one or more electromagnetic radiation sources illuminating the reflective cursor control object;

imaging the radiation reflected by the reflective cursor control object onto an optical sensor formed of a two-dimensional array of radiation sensitive pixels arranged in a plurality of rows and columns,

distinguishing on the optical sensor a radiation image of the reflective cursor control object having an intensity above a threshold intensity;

distinguishing a centroid of the radiation image;

determining a position of the centroid of the radiation image relative to the two-dimensional array of pixels;

producing electronic video signals suitable for controlling the position of a cursor on a computer-controlled display as a function of the position of the centroid of the radiation image relative to the two-dimensional array of pixels, and

generating a change in the radiation image by reducing the image intensity below the threshold and subsequently increasing the image intensity above the threshold.

39. The method of claim 38 wherein generating a change in the radiation image further comprises reducing the image intensity below the threshold and subsequently increasing the image intensity above the threshold while retaining substantially the same image position relative to the two-dimensional array of pixels.