US4861154A
Expired / Lapsed
US
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Automated visual assessment system with steady state visual evoked potential stimulator and product detector
Assignee: Northrop Grumman Corp
•
Filing: 1986-08-06
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Granted: 1989-08-29
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Expires: 2006-08-06
Abstract
Abstract An automated visual testing system is disclosed which presents an alternating steady state visual stimulus to a patient through an optical system that modifies the stimulus image. As the image changes, the patient produces evoked potentials that change. The evoked potentials are detected by a product detector which produces the amplitude of the evoked potentials. The amplitude is monitored through an analog to digital converter by a supervisor computer. The supervisor computer produces patient response curves from which it diagnoses visual system malfunction and/or prescribes correction. A control processor controls a stimulus generator to produce the image and an optical system, that includes polarizers, an astigmatism test slit or a cylindrical lense, a zoom lense system and a variable focal length test lense, transmits the image to the patient. The steady state visual potential stimulus generator is a device by which a rapidly complementing or flashing pattern can be presented to the patient. The generator allows the contrast of the image to be varied without varying luminance and allows operation in a true bicolor and multicolor mode. The product detector detects the level of the steady state evoked potential signals even in the presence of substantial background noise and extraneous electroencephalographic signals. These detectors can be used to monitor the evoked potential produced by visual, all or somatic steady state stimuli. The components described above can be used to produce a system that can determine to which of several different displays an observer is paying attention by providing images that blink at different frequencies and product detectors for each of the stimulus frequencies. The product detector producing the highest output indicates the display upon which the observer is focused.
Inventors
- 👤 Gary W. Sherwin
- 👤 Albert L. Schmidt
- 👤 Lewis F. Hanes
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 12:53
CPC Classifications
A; A61; A61B; A61B3/00; A61B3/02; A61B3/028; A61B3/032; A61B3/0325; A61B5/00; A61B5/24; A61B5/316; A61B5/369; A61B5/377
Claims Analysis
Total Claims: 20
Claim 1
Independent Claim
149 words
A visual testing apparatus, comprising: control means for stimulating the visual system of a patient with a test image at a stimulus frequency during a selected one of refractometry, acuity, astigmatism, contrast and color vision tests; said control means comprising: a control processor; a mirror stimulus generator connected to and controlled by said control processor to produce an alternating stimulus pattern image; and a lens system between the patient and said mirror stimulus generator, and connected to and controlled by said control processor, said lens system including eye drift prevention means for preventing the patient's eye from adapting to a changing stimulus; sensing means for detecting evoked potentials produced by the test image in the patient's brain at the stimulus frequency during the selected test; and analysis means for analyzing the evoked potentials produced by the patient during the selected test and displaying the results of the selected test.
Claim 2
Dependent Claim
149 words
A visual testing apparatus, comprising: control means for stimulating the visual system of a patient with a test image at a stimulus frequency during a selected one of refractometry, acuity, astigmatism, contrast and color vision tests; said control means comprising: a control processor; a mirror stimulus generator connected to and controlled by said control processor to produce an alternating stimulus pattern image; and a lens system between the patient and said mirror stimulus generator, and connected to and controlled by said control processor, said lens system including eye drift prevention means for preventing the patient's eye from adapting to a changing stimulus; sensing means for detecting evoked potentials produced by the test image in the patient's brain at the stimulus frequency during the selected test; and analysis means for analyzing the evoked potentials produced by the patient during the selected test and displaying the results of the selected test.
Claim 3
Dependent Claim
56 words
An apparatus as recited in claim 1, wherein said image is polarized and said lense system includes: a rotatable polarizer through which the test image passes; a selectable slit through which the test image passes; a zoom lense through which the test image passes; and a variable focus test lense through which the test image passes.
Claim 4
Dependent Claim
44 words
An apparatus as recited in claim 1, wherein said lense system includes: a zoom lense through which the test image passes; a variable focus cylindrical lense through which the test image passes; and a variable focus test lense through which the test image passes.
Claim 5
Dependent Claim
36 words
An apparatus as recited in claim 1, wherein said drift prevention means comprises: a television and far field lense producing a reference image; and a beam combiner that combines the test image and the reference image.
Claim 6
Dependent Claim
122 words
A visual testing apparatus, comprising: control means for stimulating the visual system of patient with a test image at a stimulus frequency during a selected one of refractometry, acuity, astigmatism, contrast and color vision tests; sensing means for detecting evoked potentials produced by the test image in the patient's brain at the stimulus frequency during the selected test, said sensing means comprising: self-preparing electrodes attachable to the patient's head for detecting evoked potentials; and a product detector, operatively connected to said electrodes and said analysis means, for detecting the amplitude of the evoked potentials at the stimulus frequency; and analysis means for analyzing the evoked potentials produced by the patient during the selected test and displaying the results of the selected test.
Claim 7
Dependent Claim
122 words
A visual testing apparatus, comprising: control means for stimulating the visual system of patient with a test image at a stimulus frequency during a selected one of refractometry, acuity, astigmatism, contrast and color vision tests; sensing means for detecting evoked potentials produced by the test image in the patient's brain at the stimulus frequency during the selected test, said sensing means comprising: self-preparing electrodes attachable to the patient's head for detecting evoked potentials; and a product detector, operatively connected to said electrodes and said analysis means, for detecting the amplitude of the evoked potentials at the stimulus frequency; and analysis means for analyzing the evoked potentials produced by the patient during the selected test and displaying the results of the selected test.
Claim 8
Dependent Claim
160 words
A visual testing apparatus, comprising: control means for stimulating the visual system of a patient with a test image at a stimulus frequency during a selected one of refractometry, acuity, astigmatism, contrast and color vision tests; sensing means for detecting evoked potentials produced by the test image in the patient's brain at the stimulus frequency during the selected test, said sensing means comprising: self-preparing electrodes attachable to the patient's head for detecting evoked potentials; and a product detector, operatively connected to said electrodes, for detecting the amplitude of the evoked potentials at the stimulus frequency; analysis means for analyzing the evoked potentials produced by the patient during the selected test and displaying the results of the selected test; and a reference product detector for detecting brain wave activity at a frequency other than the stimulus frequency, the amplitude detected by said product detector is adjusted by aid analysis means using the brain wave activity detected by said reference product detector.
Claim 9
Dependent Claim
160 words
A visual testing apparatus, comprising: control means for stimulating the visual system of a patient with a test image at a stimulus frequency during a selected one of refractometry, acuity, astigmatism, contrast and color vision tests; sensing means for detecting evoked potentials produced by the test image in the patient's brain at the stimulus frequency during the selected test, said sensing means comprising: self-preparing electrodes attachable to the patient's head for detecting evoked potentials; and a product detector, operatively connected to said electrodes, for detecting the amplitude of the evoked potentials at the stimulus frequency; analysis means for analyzing the evoked potentials produced by the patient during the selected test and displaying the results of the selected test; and a reference product detector for detecting brain wave activity at a frequency other than the stimulus frequency, the amplitude detected by said product detector is adjusted by aid analysis means using the brain wave activity detected by said reference product detector.
Claim 10
Dependent Claim
106 words
A visual testing apparatus, comprising: control means for stimulating the visual system of a patient with a test image at a stimulus frequency during a selected one of refractometry, acuity, astigmatism, contrast and color vision tests; sensing means for detecting evoked potentials produced by the test image in the patient's brain at the stimulus frequency during the selected test; and analysis means for analyzing the evoked potentials produce by the patient during the selected test and displaying the results of the selected test, said analysis means comprising a computer that filters the evoked potentials, produces result curves, and produces results values based on the result curves.
Claim 11
Dependent Claim
106 words
A visual testing apparatus, comprising: control means for stimulating the visual system of a patient with a test image at a stimulus frequency during a selected one of refractometry, acuity, astigmatism, contrast and color vision tests; sensing means for detecting evoked potentials produced by the test image in the patient's brain at the stimulus frequency during the selected test; and analysis means for analyzing the evoked potentials produce by the patient during the selected test and displaying the results of the selected test, said analysis means comprising a computer that filters the evoked potentials, produces result curves, and produces results values based on the result curves.
Claim 12
Dependent Claim
62 words
A stimulus generator for a patient, comprising: first and second light sources each having red, green and blue lights and each source capable of producing a continuously variable colored light mixture; and a patterned mirror, the first light source producing light that passes through the mirror to the patient, the second light source producing light reflected off the mirror to the patient.
Claim 13
Dependent Claim
62 words
A stimulus generator for a patient, comprising: first and second light sources each having red, green and blue lights and each source capable of producing a continuously variable colored light mixture; and a patterned mirror, the first light source producing light that passes through the mirror to the patient, the second light source producing light reflected off the mirror to the patient.
Claim 14
Dependent Claim
65 words
A stimulus generator for a patient, comprising: first and second light sources each having red, green and blue light sources; a patterned mirror, the first light source producing light that passes through the mirror to the patient, the second light source producing light reflected off the mirror to the patient; and light control means for changing activation times of the red, green and blue sources.
Claim 15
Dependent Claim
65 words
A stimulus generator for a patient, comprising: first and second light sources each having red, green and blue light sources; a patterned mirror, the first light source producing light that passes through the mirror to the patient, the second light source producing light reflected off the mirror to the patient; and light control means for changing activation times of the red, green and blue sources.
Claim 16
Dependent Claim
25 words
A generator as recited in claim 9 further comprising diffusion means for uniformly diffusing the light from said colored light sources over the mirror surface.
Claim 17
Dependent Claim
114 words
A stimulus generator for a patient, comprising: first and second light sources; a patterned mirror, the first light source producing light that passes through the mirror to the patient, the second light source producing light reflected off the mirror to the patient; a third light source washing out light from the mirror, said first through third light sources producing continuous light; first polarizing means for polarizing the light from the first and second sources in a first direction; second polarizing means for polarizing the light from the third source in a second direction perpendicular to the first direction; and a rotatable polarizer through which the light from the mirror and the third source pass.
Claim 18
Dependent Claim
114 words
A stimulus generator for a patient, comprising: first and second light sources; a patterned mirror, the first light source producing light that passes through the mirror to the patient, the second light source producing light reflected off the mirror to the patient; a third light source washing out light from the mirror, said first through third light sources producing continuous light; first polarizing means for polarizing the light from the first and second sources in a first direction; second polarizing means for polarizing the light from the third source in a second direction perpendicular to the first direction; and a rotatable polarizer through which the light from the mirror and the third source pass.
Claim 19
Independent Claim
100 words
An apparatus for determining a display to which an observer is paying attention, said apparatus comprising: display means simultaneously producing images that flicker at different frequencies, the observer viewing said display means; detection means, coupled to the observer by electrode means for contacting the observer's head, for detecting the amplitude of evoked potentials produced in the observer's brain at the different frequencies; and comparison means, operatively connected to said detection means and including means for storing amplitudes, for determining which amplitude is the largest, the largest amplitude indicating which of said display means is receiving the greatest amount of attention.
Claim 20
Independent Claim
100 words
An apparatus for determining a display to which an observer is paying attention, said apparatus comprising: display means simultaneously producing images that flicker at different frequencies, the observer viewing said display means; detection means, coupled to the observer by electrode means for contacting the observer's head, for detecting the amplitude of evoked potentials produced in the observer's brain at the different frequencies; and comparison means, operatively connected to said detection means and including means for storing amplitudes, for determining which amplitude is the largest, the largest amplitude indicating which of said display means is receiving the greatest amount of attention.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1992-08-28 | 1993-02-27 | 1993-08-29 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1996-08-28 | 1997-02-27 | 1997-08-29 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2000-08-28 | 2001-02-27 | 2001-08-29 | $7700.00 | Window Closed / Lapsed |