GB2397455A

GB2397455A - Active anti-glare visor

Info

Publication number: GB2397455A
Application number: GB0300728A
Authority: GB
Inventors: Souza Paul Gerard D
Original assignee: Individual
Current assignee: Individual
Priority date: 2003-01-14
Filing date: 2003-01-14
Publication date: 2004-07-21
Also published as: GB0300728D0

Abstract

An active <B>Anti-Glare Visor</B> 5 that provides selective anti glare properties to the visor in real time so as to mask only high intensity sources of glare 9 that appear in the field of view of user through the visor. The visor comprises an active antiglare element 2 including a closed circuit television camera 1 that exactly maps the users field of view 8 coupled to a display system, the display inserted between objective and observer and providing a negative or reversed image of zones above the glare threshold. The darkened zones on the visor effectively neutralise the glare zones by masking them while suitable glare threshold control circuitry suppresses the negative image to the visor at levels below the glare threshold. The field of view remains clear in these areas. The visor television display is implemented using a LCD matrix display with suitable polarising filters 3,4.

Description

intelligent Anti Glare Visor.

This invention relates to Improvements in or relating to an Intelligent Anti Glare Visor particularly suited for providing selective anti glare properties to the user so as to reduce glare for only high intensity sources of glare such as automobile headlights, the rising or setting sun on the horizon, street lights, reflections of metallic surfaces etc. Hitherto known anti glare screens and visors affect the viewing properties of the entire visor or screen, thus darkening the wanted portions as well as the unwanted portions in the field of view though the visor. Some variations of the anti glare screen have a gradation that varies from higher anti glare properties on the top portion and a slow decrease in the shading towards the bottom. The use of Liquid crystal displays for controlling glare is known, however the effect is the same as static screens, the difference being the ability to turn the screen on and off et will as well as to alter the level of opacity of the screen.

The object of the present invention is to develop an Intelligent Anti Glare Visor that is simple enough to implement on a commercial scale.

According to the invention there is provided an Intelligent Anti Glare Visor comprising a closed circuit television camera coupled to a television display system, the said camera focused on the same objective as the observer as seen through the visor, its field of view exactly mapping the field of view of the observer, while displaying on the television display a proportionately scaled, focus corrected, brightness or glare threshold triggered, inverted or reversed image of exactly the same field of view as seen through the said intelligent visor and inserted between the observer and objective, such that the television display superimposes the observers field of view with an identical field of view but reversed in image brightness intensity, the said television display essentially a liquid crystal display grid matrix with appropriate polarising filters whose matrix elements can operate between transparent and opaque by polarising the light that passes through them, the said grid matrix displaying a reversed or negative image of the field of view recorded by the television camera, the said negative image being restricted to those areas of the image that are above the glare threshold of the observer and scaled proportionally in reversed display intensity above the said glare threshold and suppressed for signals below the said glare threshold, the glare threshold being a measure of light intensity above which the visor element needs to be active and below which no glare suppression Is needed.

The invention will now be described with the help of the following diagrams wherein: Figure 1 A is view of a typical scone as dusk approaches. The highlighted bright spots or glare causing areas are the headlights of an automobile, a street light and the setting sun

that are in the field view of the observer.

Figure I B is an inverted or negative image of the view in Fig I A of only the bright spots or images that are above the level of the glare threshold. The highlights in this glare threshold triggered negative image are the headlights of the automobile, the street light and the setting sun. All images below the glare threshold are suppressed.

Figure 2 the same view as in Fig I A with two lines of reference A & B along which the light intensity of the scene is sampled from left to right horizontally. It also depicts the view through the visor with only the bright spots masked and the rest of the field of view unchanged which is an example of the same view with intelligent glare suppressing.

Figure 3 shows a graph depicting the sampled intensities of the light in the two horizontal scans along with a Glare Threshold level T. above which the light intensity is to be suppressed with an inverted or negative image, or below which no signal will be displayed by the visors television display. The glare points IA, 2B and 3A coincide with the street light, the headlights of the automobile and the setting sun. Al and Bl are the traces of image brightness intensity along the measured scans A and B respectively.

Figure 4 is a view of a possible implementation of the intelligent visor system.

Figure 5 is a drawing depicting the method of mapping the field of view of the observer by the closed circuit television camera and display system, while showing the positioning of the television intelligent visor between the observer and the objective. 5 is the composite visor device comprising 1, a television camera, 2 a Liquid Crystal Display TV display element, 3 and 4 are appropriate polarising filters and visor structural elements, shows the mapping of the fields of view of the camera and observer and 9, the sun, is a typical glare source in the image.

With reference to Figures 2 & 3, the Intelligent Anti Glare Visor comprises a closed circuit television camera that is adjusted to map the field of view of the observer as seen through the visor exactly. The resulting image from the camera is inverted by appropriate image processing circuitry producing a negative image which is fed to a Liquid Crystal Television display that is implemented as a layer on the windshield or visor depending upon the usage. The image is suppressed for all signals below the level threshold level T. and is inverted and a negative image is displayed for signal levels grater than threshold T. The display response above the threshold may be adjusted to respond linearly, logarithmically or in a single step depending upon the usage. The result is that there is a negative or an inverted image inserted between the viewer and the objective, exactly masking the field of view of the viewer at precisely the spots or regions required, while leaving the rest of the field of view transparent and glare free.

The Intelligent Anff Glare Visor is operated as follows: The setting of the glare threshold T is set so as to respond according to the observers comfort level while the response (instantaneous or varying) of the visor is adjusted as per requirement. No further adjustments are needed.

Claims

Claims Claim 1 An Intelligent Anti Glare Visor comprising a closed circuit

television camera coupled to a television display system, the said camera focused on the same objective as the observer as seen through the visor, its field of view exactly mapping the field of view of the observer, while displaying on the television display a proportionately scaled, focus corrected, brightness or glare threshold triggered, inverted or reversed image of exactly me same field of view as seen through the said intelligent visor and inserted between the observer and objective, such that the television display superimposes the observers field of view with an identical field of view but reversed in image brightness intensity, the said television display essentially a liquid crystal display grid matrix with appropriate polarising filters whose matrix elements can operate between transparent and opaque by polarising the light that passes through them, the said grid matrix displaying a reversed or negative image of the field of view recorded by the television camera, the said negative image being restricted to those areas of the image that are above the glare threshold of the observer and scaled proportionally in reversed display intensity above the said glare threshold and suppressed for signals below the said glare threshold, the glare threshold being a measure of light intensity above which the visor element needs to be active and below which no glare suppression is needed.

Claim 2 An Intelligent Anti Glare Visor as claimed in Claim I wherein the visor element is also an active television display device comprising a liquid crystal matrix television display that displays an inverted or reversed, brightness or glare threshold triggered image that acts as a selective glare mask.

Claim 3 A Large Date Display Mechanism substantially as described herein with reference to Figures I A, 1 B. 2, 3, 4 & 5 of the accompanying diagrams.