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US 4,400,731 AGranted
Testing display systems
AssigneeSmiths Industries Public Limited Company
InventorRichard Brown
Life of this patent
Estimating the term…
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AssigneeSmiths Industries Public Limited Company
InventorRichard Brown
Estimating the term…
Head-up display units and other display systems are tested by means of a camera having an array of light-responsive elements. The signals supplied to the display system to control the disposition of the display representation in the display area of the system, are compared with the output from the camera so as to derive an indication of the difference between the signalled disposition and the actual disposition of the representation. The display unit is mounted for angular displacement about two axes at right angles to the line-of-sight. The width of the display representation is determined by measuring the distance between two points of the same brightness on opposite sides of the center of the representation; this is done by displacing the image formed on the array across an individual element of the array. The brightness of the display representation is determined by comparison with a source that is switchable between two known brightness levels.
In apparatus for determining the disposition of a display representation in a display area of a display system of the kind including means supplying signals to affect the disposition of said display representation, the improvement wherein the apparatus includes a camera of the kind including an array of radiation-responsive elements, mounting means mounting said camera to view said display area, the camera deriving an indication of the disposition of said display representation, processing means comparing the disposition of said display representation as derived from said camera with said signals supplied to said display system thereby to derive an indication of the difference between the signalled disposition and the actual disposition of said display representation, a source of known brightness, and means for imaging radiation from said source onto said array, said processing means comparing the output from an individual one of said elements when illuminated by radiation from said display area with the output when illuminated by radiation from said source.
Apparatus for determining the disposition of a display representation provided by a head-up display system, including:
A method of determining the disposition of a display representation in a display area of a display system including the steps of:
A method of determining the disposition of a display representation in a display area of a head-up display system including the steps of:
Dependencies are inferred from the claim text.