US4365873A — Spatial frequency and contrast sensitivity test c…

Claim 1

Independent Claim 173 words

A vision sensitivity evaluation apparatus by which the concurrent effects of contrast sensitivity and spatial frequency are ascertained, comprising: a visually perceivable chart having a multiplicity of patches being systematically organized over the face of the chart into a plurality of groups; each patch comprised by a grating of alternating light and dark regions being calibrated such that its contrast distribution varies between peaks and troughs of luminance and its pattern integrates a substantially constant contrast luminance level with a substantially constant spatial frequency; said gratings in one group of patches having substantially equal contrast levels which differ from the respective contrast levels of the gratings in other groups of patches; said gratings in a different one group of patches having substantially equal spatial frequencies which differ from the respective spatial frequencies of the gratings in other different groups of patches; and said grating of each patch having a particular perceivable orientation, depending upon the threshold of visual sensitivity of a normal observer, which renders its detection by the observer subject to verification.

Claim 2

Dependent Claim 173 words

A vision sensitivity evaluation apparatus by which the concurrent effects of contrast sensitivity and spatial frequency are ascertained, comprising: a visually perceivable chart having a multiplicity of patches being systematically organized over the face of the chart into a plurality of groups; each patch comprised by a grating of alternating light and dark regions being calibrated such that its contrast distribution varies between peaks and troughs of luminance and its pattern integrates a substantially constant contrast luminance level with a substantially constant spatial frequency; said gratings in one group of patches having substantially equal contrast levels which differ from the respective contrast levels of the gratings in other groups of patches; said gratings in a different one group of patches having substantially equal spatial frequencies which differ from the respective spatial frequencies of the gratings in other different groups of patches; and said grating of each patch having a particular perceivable orientation, depending upon the threshold of visual sensitivity of a normal observer, which renders its detection by the observer subject to verification.

Claim 3

Dependent Claim 25 words

The chart recited in claim 1, wherein the contrast luminance distribution varies sinusoidally at a constant spatial frequency on the grating of any one patch.

Claim 4

Dependent Claim 42 words

The chart recited in claim 1 or 2, wherein the spatial frequency band encompassed by the patches extends from about 0.5 to 32 cycles per degree in octave steps, and the contrast range decreases from a useful upper limit of about 30%.

Claim 5

Dependent Claim 33 words

The chart recited in claim 1, wherein said gratings of said groups of patches are arranged in successive columns which decrease in contrast level and in successive rows which increase in spatial frequency.

Claim 6

Independent Claim 86 words

A method for determining the contrast and spatial frequency sensitivity of an optical and/or visual system, which comprises the steps of: successively observing a multiplicity of grating patches which vary in contrast and spatial frequency; identifying a particular perceivable orientation of each grating patch depending upon the threshold of visual sensitivity of a normal observer, which orientation renders its detection by the observer subject to verification; and ascertaining the grating detection threshold of the system for decreasing levels of contrast and increasing levels of spatial frequency.

Claim 7

Independent Claim 86 words

A method for determining the contrast and spatial frequency sensitivity of an optical and/or visual system, which comprises the steps of: successively observing a multiplicity of grating patches which vary in contrast and spatial frequency; identifying a particular perceivable orientation of each grating patch depending upon the threshold of visual sensitivity of a normal observer, which orientation renders its detection by the observer subject to verification; and ascertaining the grating detection threshold of the system for decreasing levels of contrast and increasing levels of spatial frequency.

Claim 8

Dependent Claim 42 words

The method recited in claim 5, wherein the grating contrast varies sinusoidally, the grating spatial frequency extends from about 0.5 to 32 cycles per degree in octave steps, and the patches range in contrast from a useful upper limit of about 30%.

Claim 9

Independent Claim 40 words

The method as recited in claims 5 or 6, wherein the patches are observed through an optical imaging system and compared to the result in a direct observation so as to ascertain the degradation in contrast or spatial frequency sensitivity.

Claim 10

Dependent Claim 31 words

The chart recited in claim 1, wherein the grating of each patch is disposed at one of three possible orientations: canted to the right, substantially vertical, or canted to the left.

Claim 11

Dependent Claim 22 words

The chart recited in claim 1, wherein the alternating light and dark regions comprising the grating of each patch are substantially linear.

Claim 12

Dependent Claim 117 words

Vision sensitivity evaluation apparatus including means presenting a perceivable pattern of a multiplicity of distinctly separated patches, each of said patches comprising a grating embodying successively alternated light and dark regions, the elements of which have a substantially linear character and the contrast levels and/or frequencies of occurrence of which differ in different patches, said patches presenting a range of contrasting luminance and frequency of the occurrence therein of the alternated light and dark regions of their gratings, which upon observation by a person or system may be used as an accurate basis for determining the sensitivity and range of perception of that person or system to whom or to which the patches are presented for viewing.

Claim 13

Dependent Claim 117 words

Vision sensitivity evaluation apparatus including means presenting a perceivable pattern of a multiplicity of distinctly separated patches, each of said patches comprising a grating embodying successively alternated light and dark regions, the elements of which have a substantially linear character and the contrast levels and/or frequencies of occurrence of which differ in different patches, said patches presenting a range of contrasting luminance and frequency of the occurrence therein of the alternated light and dark regions of their gratings, which upon observation by a person or system may be used as an accurate basis for determining the sensitivity and range of perception of that person or system to whom or to which the patches are presented for viewing.

Claim 14

Dependent Claim 55 words

Apparatus as in claim 10 wherein said patches are presented in groups and the degree of luminance contrast within the grating of each of said patches in one of said groups is essentially the same and differs from the degree of luminance contrast evidenced in the gratings of the patches in other of said groups.

Claim 15

Dependent Claim 46 words

Apparatus as in claim 10 wherein each said patch has the grating thereof embodying said successively alternated light and dark regions the elements of which are substantially linear in character so calibrated to present peaks and troughs of luminance across said regions in a repetitive sequence.

Claim 16

Dependent Claim 35 words

Apparatus as in claim 10 wherein the level of luminance in the grating of each of said patches varies sinusoidally in a direction transverse to the longitudinal extent of said substantially linearly configured elements thereof.

Claim 17

Dependent Claim 62 words

Apparatus as in claim 10 wherein said patches are arranged in rows and the patches of said rows are arranged to form a plurality of columns thereof and each of said columns exhibits in the patches forming the same a pattern of changing luminance across the gratings thereof which differs from that exhibited in the patches of the adjacent of said columns.

Claim 18

Dependent Claim 68 words

Apparatus as in claim 10 or claim 14 wherein said patches are arranged in rows and the said rows are arranged to form a plurality of columns of said patches and each of said rows has the patches thereof provided with gratings the frequency of the alternated dark and light regions of which differs from that of the gratings of the patches exhibited in adjacent of said rows.

Claim 19

Dependent Claim 56 words

Vision sensitivity evaluation apparatus as in claim 10 or claim 12 wherein said elements of the gratings of certain of said patches have a vertical orientation and the elements of the gratings of other of said patches have a degree of inclination from a vertical orientation in either a clockwise or counterclockwise direction with respect thereto.

Claim 20

Dependent Claim 29 words

Vision sensitivity evaluation apparatus as in claim 10 wherein said elements of each grating have a perceivable orientation by which they are distinguishable from the elements of other gratings.

Annuity Stage	Window Opens	Payment Deadline	Surcharge Period Until	Estimated Fee	Status
3.5 Years (Year 4)	1985-12-27	1986-06-28	1986-12-28	$2000.00	Window Closed / Lapsed
7.5 Years (Year 8)	1989-12-27	1990-06-28	1990-12-28	$3760.00	Window Closed / Lapsed
11.5 Years (Year 12)	1993-12-27	1994-06-28	1994-12-28	$7700.00	Window Closed / Lapsed

Spatial frequency and contrast sensitivity test chart

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