US3912399A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method of and assembly for measuring equivalent sphere illumination
Assignee: Johns Manville
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Filing: 1974-02-27
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Granted: 1975-10-14
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Expires: 1994-02-27
Abstract
Abstract The measurement of equivalent sphere illumination on a given task located in a lighted area is disclosed herein. This is accomplished by comparing the task located in the lighted area with a second task which is, in fact, illuminated with sphere illumination. The two tasks are viewed in accordance with specific optical procedures to determine the equivalent sphere illumination on the given task.
Inventors
- 👤 James William Griffith
- 👤 Robert Dale Zeller
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-06 03:52
CPC Classifications
G; G01; G01J; G01J1/00
Claims Analysis
Total Claims: 35
Claim 1
Independent Claim
306 words
A method of determining the amount of equivalent sphere illumination on a given task as viewed from a given viewing point, comprising: a. locating said given task and a contrasting colored given reference in a lighted first area, said task and reference being oriented in a fixed way as viewed from said viewing point; b. at said viewing point, viewing said task and reference through adjustable light filtering means; c. adjusting said light filtering means to an adjusted position to provide specific visibility of said task from said viewing point and through said filtering means while causing the luminance of said reference at least to appear unchanged as viewed through said adjusted filtering means from a predetermined point behind said filtering means regardless of the adjusted position of said light filtering means; d. positioning a second task and a second reference, respectively similar in color to said given task and given reference, in a second area, said second task and second reference, as viewed from an associated viewing point, being oriented in substantially the same way as said given object and given reference are oriented as viewed from said given viewing point; e. illuminating said second task and second reference with sphere illumination; f. with said light filtering means fixed in said adjusted position, viewing said second task and second reference through said filterinG means from said associated viewing point; g. varying the intensity of sphere illumination on said second task and second reference until the visibility of said second task, as viewed from said associated viewing point through said filtering means, is substantially equal to said specific visibility while causing the luminance of said second reference at least to appear unchanged as viewed through said filtering means from a associated predetermined point; and h. thereafter, measuring the intensity of sphere illumination on said second task.
Claim 2
Independent Claim
306 words
A method of determining the amount of equivalent sphere illumination on a given task as viewed from a given viewing point, comprising: a. locating said given task and a contrasting colored given reference in a lighted first area, said task and reference being oriented in a fixed way as viewed from said viewing point; b. at said viewing point, viewing said task and reference through adjustable light filtering means; c. adjusting said light filtering means to an adjusted position to provide specific visibility of said task from said viewing point and through said filtering means while causing the luminance of said reference at least to appear unchanged as viewed through said adjusted filtering means from a predetermined point behind said filtering means regardless of the adjusted position of said light filtering means; d. positioning a second task and a second reference, respectively similar in color to said given task and given reference, in a second area, said second task and second reference, as viewed from an associated viewing point, being oriented in substantially the same way as said given object and given reference are oriented as viewed from said given viewing point; e. illuminating said second task and second reference with sphere illumination; f. with said light filtering means fixed in said adjusted position, viewing said second task and second reference through said filterinG means from said associated viewing point; g. varying the intensity of sphere illumination on said second task and second reference until the visibility of said second task, as viewed from said associated viewing point through said filtering means, is substantially equal to said specific visibility while causing the luminance of said second reference at least to appear unchanged as viewed through said filtering means from a associated predetermined point; and h. thereafter, measuring the intensity of sphere illumination on said second task.
Claim 3
Dependent Claim
128 words
A method according to claim 1 wherein said step of causing the luminance of said given reference at least to appear unchanged as viewed through said adjusted filtering means from said predetermined point includes: a. directing an adjustable amount of light from a light source towards said light filtering means, b. positioning said filtering means and said predetermined point relative to one another and relative to the light from said source such that at least some of the light is reflected off of said light filtering means and in the direction of said predetermined point, and c. adjusting the amount of said reflected light so as to cause the luminance of said given reference to appear unchanged as viewed through said adjusted filtering means from said predetermined point.
Claim 4
Dependent Claim
132 words
A method according to claim 2 wherein said step of causing the luminance of said second reference at least to appear unchanged as viewed through said adjusted filtering means from said associated predetermined point includes: a. directing an adjustable amount of light from a light source towards said light filtering means, b. positioning said filtering means and said associated predetermined point relative to one another and relative to the light from said last-mentioned source such that at least some of the light is reflected off of said light filtering means and in the direction of said associated point, and c. adjusting the amount of said last-mentioned reflected light so as to cause the luminance of said second reference to appear unchanged as viewed through said adjusted filtering means from said associated point.
Claim 5
Dependent Claim
57 words
A method according to claim 3 wherein: a. said predetermined point and said associated predetermined point are identical to said given viewing point and associated viewing point, respectively, and b. said steps of causing the luminance of said given reference and said second reference includes respectively viewing said references from said viewing points by the individual eye.
Claim 6
Dependent Claim
17 words
A method according to claim 1 wherein said given task and said second task are viewed alternately.
Claim 7
Dependent Claim
22 words
A method according to claim 1 wherein both of said tasks and their associated references are viewed from substantially the same point.
Claim 8
Dependent Claim
25 words
A method according to claim 1 wherein said given task and given reference are respectively substantially identical to said second task and said second reference.
Claim 9
Dependent Claim
41 words
A method according to claim 1 wherein said second task and said second reference are positioned in a second area partially defined by a surface which comprises a segment of a sphere and which substantially uniformly diffusely reflects light directed thereon.
Claim 10
Dependent Claim
13 words
A method according to claim 8 wherein said surface segment comprises a hemisphere.
Claim 11
Dependent Claim
57 words
A method according to claim 1 wherein each of said references comprises a flat surface, wherein each of said tasks comprises a symbol on a respective one of said flat surfaces and wherein each of said tasks and references are oriented such that optically they are viewed at an angle from perpendicular lines through said flat surfaces.
Claim 12
Dependent Claim
22 words
A method according to claim 10 wherein said flat surfaces lie in a horizontal plane and wherein said angle is approximately 25*.
Claim 13
Dependent Claim
27 words
A method according to claim 10 wherein said flat surfaces lie in a plane which extends 15* from the horizontal and wherein said angle is approximately 10*.
Claim 14
Dependent Claim
13 words
A method according to claim 1 wherein said specific visibility is threshold visibility.
Claim 15
Independent Claim
379 words
A method of determining the amount of equivalent sphere illumination on an object as viewed from a selected viewing point, comprising: a. positioning a specific object including a flat surface having a darker colored symbol theron in a lighted first area; b. selecting a viewing point and orienting said object relative to said point such that, at said point, the flat surface of said object is viewed at an acute angle to a line normal to said surface; c. at said viewing point, viewing said surface through adjustable light filtering means; d. adjusting said light filtering means to a position which will provide threshold visibility of said symbol, as viewed from said viewing point and causing the luminance of said flat surface at least to appear unchanged as viewed through said adjusted filtering means from said viewing point regardless of the adjusted position of said filtering means; e. positioning a reference object including a flat surface having a symbol thereon in a second area, both of said object surfaces being of the same color and both of said symbols being of the same color, said second area being partially defined by a hemispherical surface which substantially uniformly diffusely reflects light directed thereon; f. orienting said reference object relative to said selected viewing point such that, at said point, the flat surface of said reference object is viewed at an acute angle to a line normal to said last-mentioned surface, said last-mentioned angle being substantially identical to the angle at which said specific object is in view; g. illuminating said reference object with sphere illumination; h. with said light filtering means in said adjusted position, viewing said reference object through said filtering means from said viewing point; i. varying the intensity of sphere illumination on said reference object until the visibility of the symbol on said reference object, as viewed from said viewing point through said light filtering means, is substantially equal to the threshold visibility of the symbol on said specific object as viewed from said viewing point through said filtering means and causing the luminance of the flat surface of said reference object at least to appear unchanged as viewed through said adjusted filtering means from said viewing point; and j. thereafter measuring the intensity of sphere illumination.
Claim 16
Independent Claim
379 words
A method of determining the amount of equivalent sphere illumination on an object as viewed from a selected viewing point, comprising: a. positioning a specific object including a flat surface having a darker colored symbol theron in a lighted first area; b. selecting a viewing point and orienting said object relative to said point such that, at said point, the flat surface of said object is viewed at an acute angle to a line normal to said surface; c. at said viewing point, viewing said surface through adjustable light filtering means; d. adjusting said light filtering means to a position which will provide threshold visibility of said symbol, as viewed from said viewing point and causing the luminance of said flat surface at least to appear unchanged as viewed through said adjusted filtering means from said viewing point regardless of the adjusted position of said filtering means; e. positioning a reference object including a flat surface having a symbol thereon in a second area, both of said object surfaces being of the same color and both of said symbols being of the same color, said second area being partially defined by a hemispherical surface which substantially uniformly diffusely reflects light directed thereon; f. orienting said reference object relative to said selected viewing point such that, at said point, the flat surface of said reference object is viewed at an acute angle to a line normal to said last-mentioned surface, said last-mentioned angle being substantially identical to the angle at which said specific object is in view; g. illuminating said reference object with sphere illumination; h. with said light filtering means in said adjusted position, viewing said reference object through said filtering means from said viewing point; i. varying the intensity of sphere illumination on said reference object until the visibility of the symbol on said reference object, as viewed from said viewing point through said light filtering means, is substantially equal to the threshold visibility of the symbol on said specific object as viewed from said viewing point through said filtering means and causing the luminance of the flat surface of said reference object at least to appear unchanged as viewed through said adjusted filtering means from said viewing point; and j. thereafter measuring the intensity of sphere illumination.
Claim 17
Dependent Claim
237 words
A method according to claim 14 wherein: a. said step of causing the luminance of said surface of said specific object to appear unchanged as viewed through said adjusted filtering means from said viewing point includes i. directing a first adjustable amount of light from a light source towards said light filtering means, ii. positioning said filtering means and said viewing point relative to one another and relative to said beam of light such that at least some of the light from said source is reflected off of said filtering means and in the direction of said viewing point, and iii. adjusting the amount of said reflected light so as to cause the luminance of said last-mentioned surface to appear unchanged as viewed through said adjusted filtering means from said viewing point; and b. said step of causing the luminance of said surface of said reference object to appear unchanged as viewed through said adjusted filtering means from said viewing point includes i. directing a second adjustable amount of light from a light source towards said positioned light filtering means such that at least some of the light is reflected off of said filtering meams and in the direction of said viewing point, and ii. adjusting the amount of said last-mentioned reflected light so as to cause the luminance of said last-mentioned surface to appear unchanged as viewed through said adjusted filtering means from said viewing point.
Claim 18
Dependent Claim
94 words
A method according to claim 15 wherein said speCific object and said reference object are viewed alternately and including: a. viewing a portion of the surface of said specific object from said viewing point but outside said filtering means while simultaneously viewing the symbol of said specific object through said filtering means from said viewing point; and b. viewing a portion of the surface of said reference object from said viewing point but outside said filtering means while simultaneously viewing the symbol of said reference object through said filtering means from said viewing point.
Claim 19
Dependent Claim
20 words
A method according to claim 16 wherein said portions of each of said surfaces are viewed by the individual eye.
Claim 20
Dependent Claim
20 words
A method according to claim 16 wherein said portions of each of said surfaces are viewed by optical sensing means.
Claim 21
Independent Claim
253 words
A method of determining the amount of equivalent sphere illumination on a given task as viewed from a given viewing point, comprising: a. locating said given task and a contrasting colored given reference in a lighted first area, said task and reference being oriented in a fixed way as viewed from said viewing point; b. at said viewing point, viewing said task and said reference; c. as viewed from said viewing point, optically changing the contrast between said task and reference to a specific level while causing the luminance of said reference to appear unchanged from said viewing point; d. positioning a second task and a second reference, respectively similar in color to said given task and given reference, in a second area, said second task and second reference, as viewed from an associated viewing point, being oriented in substantially the same way as said given task and given reference are oriented as viewed from said given viewing point; e. illuminating said second task and second reference with sphere illumination; f. at said associated viewing point, viewing said second task and second reference; g. varying the intensity of sphere illumination on said second task and second reference until the contrast between said second task and second reference, as viewed from said associated viewing point is substantially equal to said specific contrast level while causing the luminance of said second reference to appear unchanged as viewed from said associated viewing point; and h. thereafter, measuring the intensity of sphere illumination on said second task.
Claim 22
Independent Claim
253 words
A method of determining the amount of equivalent sphere illumination on a given task as viewed from a given viewing point, comprising: a. locating said given task and a contrasting colored given reference in a lighted first area, said task and reference being oriented in a fixed way as viewed from said viewing point; b. at said viewing point, viewing said task and said reference; c. as viewed from said viewing point, optically changing the contrast between said task and reference to a specific level while causing the luminance of said reference to appear unchanged from said viewing point; d. positioning a second task and a second reference, respectively similar in color to said given task and given reference, in a second area, said second task and second reference, as viewed from an associated viewing point, being oriented in substantially the same way as said given task and given reference are oriented as viewed from said given viewing point; e. illuminating said second task and second reference with sphere illumination; f. at said associated viewing point, viewing said second task and second reference; g. varying the intensity of sphere illumination on said second task and second reference until the contrast between said second task and second reference, as viewed from said associated viewing point is substantially equal to said specific contrast level while causing the luminance of said second reference to appear unchanged as viewed from said associated viewing point; and h. thereafter, measuring the intensity of sphere illumination on said second task.
Claim 23
Dependent Claim
184 words
An assembly for determining the amount of equivalent sphere illumination of a given task, comprising: a. means for supporting said given task and a contrasting colored given reference in a lighted area; b. a substantially closed housing including means for supporting a second task and a second contrasting colored reference therein; c. means for illuminating said second task and said second reference within said housing with sphere illumination; d. means for adjusting the intensity of sphere illumination on said second task and second reference; e. adjustable light filtering means; f. means simultaneously viewing said given task and given reference through said light filtering means and for simultaneously viewing said second task and second reference through said light filtering means, whereby the visibility of said tasks, as viewed through said filtering means, can be altered by adjusting said light filtering means; g. means for making the luminance of said references at least appear constant, as viewed through said filtering means, regardless of changes in visibility of said tasks; and h. means for measuring the intensity of sphere illumination on said second task and second reference.
Claim 24
Dependent Claim
184 words
An assembly for determining the amount of equivalent sphere illumination of a given task, comprising: a. means for supporting said given task and a contrasting colored given reference in a lighted area; b. a substantially closed housing including means for supporting a second task and a second contrasting colored reference therein; c. means for illuminating said second task and said second reference within said housing with sphere illumination; d. means for adjusting the intensity of sphere illumination on said second task and second reference; e. adjustable light filtering means; f. means simultaneously viewing said given task and given reference through said light filtering means and for simultaneously viewing said second task and second reference through said light filtering means, whereby the visibility of said tasks, as viewed through said filtering means, can be altered by adjusting said light filtering means; g. means for making the luminance of said references at least appear constant, as viewed through said filtering means, regardless of changes in visibility of said tasks; and h. means for measuring the intensity of sphere illumination on said second task and second reference.
Claim 25
Dependent Claim
33 words
An assembly according to claim 20 wherein said viewing means includes means for alternately viewing said given task and given reference and said second task and second reference from the same viewing point.
Claim 26
Dependent Claim
111 words
An assembly according to claim 20 wherein: a. said light filtering means comprises a device which allows at least some light to pass thErethrough from a first surface to a second surface of the device and for reflecting at least some light off of said second surface, and b. said means for making the luminance of said references appear constant includes means for directing light onto the second surface of said device whereby at least some of the light is reflected off of said second surface, said device being oriented to direct said reflected light parallel with the light passing through the device from said first surface to said second surface.
Claim 27
Dependent Claim
24 words
An assembly according to claim 22 wherein said light directing means includes means for alternately directing two different beams of light toward said device.
Claim 28
Dependent Claim
62 words
An assembly according to claim 20 wherein said light filtering means is positioned relative to said viewing means such that a first portion and a second portion of each of said references can be simultaneously viewed in side-by-side relationship, one of said portions being viewed through said light filtering means and the other of said portion being viewed outside said filtering means.
Claim 29
Dependent Claim
40 words
An assembly according to claim 24 including optical sensing means for comparing the luminance of said one portion as it appears from behind said filtering means with the luminence of said other portion as it appears outside said filtering means.
Claim 30
Dependent Claim
28 words
An assembly according to claim 20 wherein said illuminating means includes an internal hemispherical surface defined by said housing, which surface substantially uniformly diffusely reflects light directed thereon.
Claim 31
Dependent Claim
28 words
An assembly according to claim 26 wherein said means for supporting said reference object includes a flat surface extending entirely across the circular periphery of said hemispherical surface.
Claim 32
Dependent Claim
41 words
an assembly according to claim 20 wherein said viewing means comprises an arrangement for alternately viewing both of said tasks from a common viewing point through said adjustable light filtering means when said objects are supported by their associated supporting means.
Claim 33
Dependent Claim
27 words
An assembly according to claim 28 wherein said arrangement includes light direction changing means oriented such that both of said tasks are viewed indirectly from said point.
Claim 34
Dependent Claim
446 words
an assembly for determining the amount of equivalent sphere illumination on a given task, comprising: a. means for supporting said given task and a contrasting colored given reference in a lighted area; b. a substantially closed housing including i. an internal hemispherical surface which substantially uniformly diffusely reflects light directed thereon, and ii. an internal flat surface capable of passing light therethrough and adapted to support a second task and contrasting colored second reference; c. means providing light through said flat surface and into said housing for illuminating said second task and second reference within said housing with sphere illumination; d. means for varying the light passing through said flat surface and into said housing whereby to vary the intensity of sphere illumination on said second task and second reference; e. an optical device having opposite first and second surfaces, said device being capable of passing variable amounts of light therethrough from said first surface to said second surface along a predetermined path and being capable of reflecting off of said second surface at least some light which is directed onto said second surface; f. means for supporting said optical device in predetermined orientation; g. means for viewing simultaneously said given task and a portion of said given reference from a predetermined viewing point through said optical device and for alternatively viewing simultaneously said second task and a portion of said second reference from said viewing point through said optical device, whereby the visibility of said tasks, as viewed through said device from said viewing point, can be altered by varying the amount of light passing through said device from said first surface to saId second surface, said optical device being positioned such that i. a second portion of said given reference can be viewed from said viewing point simultaneously with the first-mentioned portion thereof but outside said optical device, ii. a second portion of said second reference can be viewed from said viewing point simultaneously with the first-mentioned portion thereof but outside said optical device; h. means for making the luminance of said first-mentioned reference portion at least appear unchanged, as viewed through said optical device, regardless of the changes in visibility of said tasks, said last-mentioned means including means for alternatively directing two beams of light to the second surface of said optical device, whereby light from said beams is reflected off of said second surface in the same direction as light passing through said device from said first surface to said second surface, and means for varying the amount of light directed to said second surface; and i. means for measuring the intensity of sphere illumination on said second task and second reference.
Claim 35
Dependent Claim
446 words
an assembly for determining the amount of equivalent sphere illumination on a given task, comprising: a. means for supporting said given task and a contrasting colored given reference in a lighted area; b. a substantially closed housing including i. an internal hemispherical surface which substantially uniformly diffusely reflects light directed thereon, and ii. an internal flat surface capable of passing light therethrough and adapted to support a second task and contrasting colored second reference; c. means providing light through said flat surface and into said housing for illuminating said second task and second reference within said housing with sphere illumination; d. means for varying the light passing through said flat surface and into said housing whereby to vary the intensity of sphere illumination on said second task and second reference; e. an optical device having opposite first and second surfaces, said device being capable of passing variable amounts of light therethrough from said first surface to said second surface along a predetermined path and being capable of reflecting off of said second surface at least some light which is directed onto said second surface; f. means for supporting said optical device in predetermined orientation; g. means for viewing simultaneously said given task and a portion of said given reference from a predetermined viewing point through said optical device and for alternatively viewing simultaneously said second task and a portion of said second reference from said viewing point through said optical device, whereby the visibility of said tasks, as viewed through said device from said viewing point, can be altered by varying the amount of light passing through said device from said first surface to saId second surface, said optical device being positioned such that i. a second portion of said given reference can be viewed from said viewing point simultaneously with the first-mentioned portion thereof but outside said optical device, ii. a second portion of said second reference can be viewed from said viewing point simultaneously with the first-mentioned portion thereof but outside said optical device; h. means for making the luminance of said first-mentioned reference portion at least appear unchanged, as viewed through said optical device, regardless of the changes in visibility of said tasks, said last-mentioned means including means for alternatively directing two beams of light to the second surface of said optical device, whereby light from said beams is reflected off of said second surface in the same direction as light passing through said device from said first surface to said second surface, and means for varying the amount of light directed to said second surface; and i. means for measuring the intensity of sphere illumination on said second task and second reference.
References Cited (Backward Citations)
No citation records indexed.
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