WO2017130188A1 - Technique for detecting a light source illuminating an object - Google Patents

Technique for detecting a light source illuminating an object Download PDF

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Publication number
WO2017130188A1
WO2017130188A1 PCT/IL2017/050083 IL2017050083W WO2017130188A1 WO 2017130188 A1 WO2017130188 A1 WO 2017130188A1 IL 2017050083 W IL2017050083 W IL 2017050083W WO 2017130188 A1 WO2017130188 A1 WO 2017130188A1
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WO
WIPO (PCT)
Prior art keywords
light
surface
object
non
pattern
Prior art date
Application number
PCT/IL2017/050083
Other languages
French (fr)
Inventor
Menachem Dov ZAHAVI
Gregory ZLOTNIK
Original Assignee
Zahavi Menachem Dov
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Priority to US201662286910P priority Critical
Priority to US62/286,910 priority
Application filed by Zahavi Menachem Dov filed Critical Zahavi Menachem Dov
Publication of WO2017130188A1 publication Critical patent/WO2017130188A1/en

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Classifications

    • BPERFORMING OPERATIONS; TRANSPORTING
    • B60VEHICLES IN GENERAL
    • B60JWINDOWS, WINDSCREENS, NON-FIXED ROOFS, DOORS, OR SIMILAR DEVICES FOR VEHICLES; REMOVABLE EXTERNAL PROTECTIVE COVERINGS SPECIALLY ADAPTED FOR VEHICLES
    • B60J3/00Antiglare equipment associated with windows or windscreens; Sun visors for vehicles
    • B60J3/04Antiglare equipment associated with windows or windscreens; Sun visors for vehicles adjustable in transparency
    • HELECTRICITY
    • H05ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05BELECTRIC HEATING; ELECTRIC LIGHTING NOT OTHERWISE PROVIDED FOR
    • H05B37/00Circuit arrangements for electric light sources in general
    • H05B37/02Controlling
    • H05B37/0209Controlling the instant of the ignition or of the extinction
    • H05B37/0218Controlling the instant of the ignition or of the extinction by the ambient light
    • YGENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02BCLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO BUILDINGS, e.g. HOUSING, HOUSE APPLIANCES OR RELATED END-USER APPLICATIONS
    • Y02B20/00Energy efficient lighting technologies
    • Y02B20/40Control techniques providing energy savings
    • Y02B20/46Control techniques providing energy savings based on detection of the illumination level

Abstract

A technique for detecting a light source illuminating an object, using a light detecting surface which is a light filtering surface adapted to exhibit non-uniform transparency over the surface in the following manner: when the light filtering surface is placed between the object and the light source, it allows determining a specific area thereof which currently passes more light from the light source to the object, than other areas of the light filtering surface.

Description

Technique for detecting a light source illuminating an object

Field of the Invention

The invention relates to a technique for detecting a light source which illuminates an object, for example to a technique for determining dazzling light sources and protecting the object there-from.

Background of the Invention

One of the sources of hazards to car drivers, sportsmen, etc. is dazzling by the sun or by other bright light source.

The common practice is to use sunglasses or a kind of a visor. For example, a visor may be installed at the top of a car window (for example a windshield), but this has the following drawbacks:

It occupies and obscures a large portion of the driver's field of view.

It requires the driver to manipulate the visor for adjusting it.

It provides protection only against glaring lights coming from relatively high angles.

There are a number of suggestions to overcome these drawbacks by automatic fast blocking the source of dazzle and with minimal blocking of the rest of the field of view. For example, it can be done by the use of a visor consisting of electronically controlled pixels, a detector locating the dazzling light sources, means for calculation of the pixels to be darkened to protect the eyes of the driver, while leaving the rest of the visor transparent.

Some of the patents propose to implement the above approach by using special eyeglasses, other propose some eye or even pupil tracking, some require the "optical sensor" - e.g. eyes - to be at a known position, some assume that a sufficient, quite a large area of the visor will be blocked to compensate for eye location uncertainties. The patents striving to achieve optimal blocking, usually propose a system with the following functions:

· a sensor A to detect and measure direction of dazzling light sources.

• a sensor B to measure the "optical sensor" - eyes location (Direction/angle from sensor to eyes) • a processor to determine location of blocking pixels on the visor, based on the results received from sensors A and B .

The above functions define a three-dimensional problem being a dynamic one. If, for example, sensor B determines location of the eyes (by noting direction from the sensor and measuring a suitable angle), the sensor cannot know the range to the eyes, and as there is a parallax between the sensor and the visor, this would require enlargement of the blocking area.

In general, drawbacks of such a known system are at least as follows: the described system is rather complex and requires very precise and stable installation of both the sensors and the visor; the system still dictates quite a large blocking area on the visor.

Object and Summary of the Invention

The object of this invention is to propose a more effective technique for light detecting, which would ensure that position and direction of a light source illuminating an object is detected more precisely. Consequently, that would allow controlling active screens/visors more accurately. A practical object, important for drivers and sportsmen, is to provide a solution for anti-dazzling, with the minimal obstruction to the field of view and without the need in strict optical alignment and complex calculations.

Let us introduce some terms.

The term "light filtering surface" will be understood as a surface having areas with different transparency. One specific embodiment of such a surface is a light filtering active (controllable) surface.

The term "light-filtering active surface" will be understood as a surface comprising multiple controllable pixels, wherein each of the pixels may controllably, selectively change its transparency from being essentially transparent up to being essentially opaque (blocked) so as to block light passage there-through. It should be understood that in principle, such a pixel may controllably become semi-transparent. For example, the active surface may be in the form of an active coating/layer, active screen, visor, windshield, sunglasses or the like. The active surface may be implemented, for example, by LCD technology. The concept of the invention may be formulated as a technique where a light-filtering surface (for example, a light filtering active surface) serves as a light detecting surface, i.e. a tool for determining which specific area/s of that surface currently pass more light from an external source to an object, than other areas of the surface. Such a new function of the light filtering surface a) makes it a new product per se, b) may then be used for modifying transparency of such determined specific area/s, for example to protect the object from a dazzling/glaring light.

In view of the above implementations, the term light filtering surface may be used in the present description and claims intermittently with light detecting surface, light detecting active surface, light protective surface, or just active surface, according to its specific purpose.

The term "light detecting" in this description should be understood as determining such specific area/s of a light-filtering surface, which currently pass more light from an external source to an object, than other areas of that surface. The fact of determining such specific areas actually means that position and direction of the light illuminating the object have been detected.

The terms "external source" and "source of external light" may be used intermittently with a term "light source" .

The proposed concept may be formulated in terms of device, system, method and software product.

According to a first aspect of the invention, there is provided a tool for detecting a light source illuminating an object, the tool comprises a light detecting surface being a light filtering surface adapted to serve as a light guide exhibiting nonuniform transparency over the surface in such a manner that, when placed between the object and said light source, the light detecting surface allows determining a specific area of this same surface, which currently passes more light from the light source to the object, than other areas of said light detecting surface.

The tool may be adapted for detecting one or more light sources illuminating the object, by determining one or more said specific areas respectively corresponding to said light sources.

The light detecting surface may be a passive (non-controllable) light-filtering surface or an active (controllable) light filtering surface.

The light detecting surface may exhibit the non-uniform transparency in place (i.e. concerning location of specific areas/pixels over the surface) and/or in time (i.e., dynamically).

More specifically, the light detecting surface (serving as a light guide having a non-uniform - in place and/or in time - transparency/light conductivity) is capable of mapping light on said object in such a manner, that design of the mapped light ("light design") allows recognizing said specific areas of the surface.

For performing the above-mentioned mapping operation, the light detecting surface may be provided with (or may exhibit) a non-uniform light-filtering pattern. In other words, the non-uniform light-filtering pattern is one of the means to turn the surface into the light guide with non-uniform light conductivity and to cause it mapping said light onto the object and creating the light design on the object.

It should be kept in mind that in the description, the term "pattern" is associated with the light-filtering surface, while the term "design" is associated with mapping of light on the object through the pattern. The tool may be further adapted for controllably regulating transparency of the determined specific areas. For that purpose, various options exist.

The tool may further comprise an additional, active (controllable) light- filtering surface serving as light regulating surface capable of controllably and selectively changing transparency thereof.

The light regulating surface may be placed on said passive light-filtering surface so that their surfaces (i.e. respective areas thereof) substantially coincide. Alternatively, the light detecting surface may itself constitute an active (controllable) light-filtering surface. In other words, the light detecting active surface may simultaneously be used as a controllable light regulating surface capable of controUably and selectively changing transparency of the determined specific area/s.

In one application of the technique, transparency of such areas may be controUably decreased up to becoming opaque (i.e., light blocking), so as to protect an object of interest or a part thereof from a dazzling/glaring light source.

The light filtering active surface thus becomes both a light detecting and a light- protective active surface.

However, if the light protective surface is initially not fully transparent, transparency of the determined area/s may be increased (in case such an effect is required for some purpose in any different application).

The object to be protected from the glaring light may be, for example, a user's face, a user's eyes region, pupil(s) of the eye(s), lens of a camera or of a binocular, another optical device, etc.

It should be understood that the controllable (active) light filtering surface is by definition the one adapted to controUably change transparency of its pixels. In one version of the invention, the light filtering active surface is adapted to block its specific area(s) which are determined either by the same surface, or by another light- filtering surface adapted to exhibit non-uniform transparency.

It should be noted that when the active light-filtering surface serves both as a light protective surface and a light detecting tool, the ability of determining said specific area(s) is based on an additional, inventive function of the active surface to controUably exhibit non-uniform transparency pattern (thereby guiding external light there-through and mapping it on the object). How the determining is performed based on the mapped light, will be described further on in the description.

The light-filtering pattern of the light detecting surface may be permanent, controllable or combined.

The permanent light-filtering pattern of the light detecting surface (being it active or passive) may be achieved, for example, by providing it with a preliminarily added permanent light blocking pattern ( for example, a printed non- transparent pattern).

The controllable light-filtering pattern of the active surface may be controllably made static, dynamic or combined.

Possible implementations of the proposed tool can be an integral or non- integral part of a vehicle windshield, a vehicle visor, of sunglasses, of a visor of a headset, of a headwear piece, of an active shield for an optical device (for example, for an optical sensor), etc.

Actually, the above-mentioned or other articles can be respectively claimed as various devices comprising the proposed tool or the proposed system ( see below).

According to a second aspect of the invention, there is provided a system comprising the described light detecting tool.

The mentioned system may comprise:

-a first light filtering surface being the light detecting surface,

- a second light filtering surface being the active light regulating surface,

wherein said first and second surfaces

being either placed in close proximity to one another, or constituting a common active light filtering surface, and

being positioned between the object and one or more light sources;

- a camera for monitoring the object illuminated by the light via said first and second surfaces,

- a processor for

receiving and processing data from the camera,

determining, based on the data, the specific area of the first surface passing more light to the object than other areas of the first surface, and

controlling the second surface to selectively regulate transparency of a region thereof, corresponding to the determined specific area of the first surface. The first surface may be inactive or active, and may exhibit a non-uniform light- filtering pattern capable of mapping a suitable light design on the object.

If the two surfaces are both active (or form the common light filtering active surface), the processor may be adapted to control the first one (or the common light filtering active surface) to controllably exhibit a non-uniform light filtering pattern for mapping external light so as to obtain a light design on the object, and then - to process the data on said light design, obtained from the camera.

The system may synchronize the displaying of the light-filtering pattern with the camera period, so as to minimize time required for detection (acquisition) of the design created by said pattern on the object.

It goes without saying that, for performing the above-mentioned functions, the processor should be provided with suitable software (i.e., a software product which will be defined below).

The term "selective regulation" (or "selective blocking") means that the transparency regulation should be performed only in the mentioned determined/recognized area(s) of the light regulating active surface. Preferably, the regulation starts whenever said specific area(s) pass excessive external light to the object (or to a critical part thereof). Actually, the above-mentioned system may be embedded in a vehicle, in a piece of headwear, in eyeglasses, etc. Analogously, any of such appliances comprising the proposed system can be claimed as are.

According to a third aspect of the invention, there is also provided a method for detecting light source(s) illuminating an object, by using the above-described tool (comprising at least said light detecting surface).

The method may comprise the following steps:

ensuring that said tool, exhibiting non-uniform transparency over the light detecting surface, is positioned between a light source and the object,

- getting the object illuminated by the light source through the tool,

obtaining a light design on the object, resulting from mapping the light on the object by the tool, determining the specific area(s) of the detecting surface, currently passing more light than other areas of the tool, by detecting on said object fragment(s) of the light design, indicative of said specific area(s).

Additionally, the method may comprise a step of regulating intensity of light mapped on the object, by using the tool comprising the light regulating active surface and by controlling transparency of said light regulating active surface at area(s) corresponding to said determined specific area(s) of the light detecting surface.

For example, the step of regulating intensity may be performed for protecting the object from dazzling light of said light source, and may comprise:

controllably blocking said area(s) of the light regulating active surface, whenever intensity of said light design fragment(s) exceeds a predetermined (higher) threshold.

To understand the difference between the determining step/function and the blocking step/function of the active surface, one should note that the determining function precedes the blocking function but may be performed constantly, as a background operation. In other words, the determining step/function may continue after the blocking is performed, in order to monitor the object and to adjust the blocked area/s if necessary.

As mentioned above, the non-uniform transparency (formed by the non-uniform light filtering pattern) may be static, dynamic or combined.

The method may comprise a step of controllably creating the light filtering pattern of any shape in the light detecting active surface, for further mapping external light onto the object.

As also mentioned, the step of creating/displaying such a light filtering pattern may be performed in synchronization with a camera period, thus minimizing the time required for detection (acquisition) of the design created by said pattern on the object.

The method (for example, the anti-dazzle method) may further comprise: a step of tracking the light source by monitoring said light design of the mapped light on the object, and

based on the monitoring results, deciding whether

a) to keep blocked the previously blocked area(s),

b) to unblock the previously blocked area(s),

c) to block other area(s) of the active surface - for example, to shift the blocked area(s), or to block additional area(s)).

It should be noted that the monitoring (tracking) of the light level on the object, performed after the blocking has been made, may tell whether the blocking is effective or not. Corrections may be applied, for example transparency of the determined area/s may be further decreased, if possible. Alternatively or in addition, borders and square of the determined area may be adjusted to compensate relative movement of the dazzling light source with respect to the object.

The method may comprise removing said blocking from the previously determind area(s). It may happen if light intensity of non-determined areas of the light design decreases under a lower threshold, or if other area(s) are determined as currently passing external light with greater intensity (e.g., exceeding the higher threshold) .

Further, the method may comprise detecting and blocking more than one dazzling light sources. For example, they may be blocked one after another, by successively blocking multiple areas of the light regulating active surface and without unblocking the previously blocked ones while their intensity still remains above the predetermined higher threshold.

An additional aspect of the invention is a software product enabling operation of the proposed tool or of the proposed system according to the proposed method.

A software product may comprise computer implementable instructions and/or data for carrying out the above- described method, the software product being stored on an appropriate computer readable storage medium so that the software is capable of enabling operations of said method when used in a computerized system. We will now continue with more detailed disclosure of the proposed tool and the proposed system.

More specifically, the active light filtering (light-protective) surface may exhibit a non-uniform light-filtering pattern formed at least by transparent and non-transparent elements of the surface. Non-uniformity of the pattern is such that different sections of the surface are distinguishable by local portions/fragments of the pattern placed on such different sections.

As already noted, the mentioned light filtering pattern may be permanently provided on the active surface ( for example by printing signs on the surface) , but may be controllably/electronically generated on the active surface (i.e., determined by software). The latter is preferable at least since: it is more universal and may be adjusted for any implementation, does not impede the field of view and may allow keeping the pattern optimal when the object moves.

Such an active surface provided with the described light filtering pattern, when illuminated by an external light source from one side, creates the mentioned design (i.e., one or more light/shade printouts) of mapped light on any object positioned behind the active surface. Each specific design of mapped light depends on direction of the external light; it is created by one or more portions of the light filtering pattern (for example, non-uniform pattern), placed on respective sections of the active surface which have conducted the light.

As already agreed above, the term "pattern" is associated with the active surface, while the term "design" is associated with mapping of light on the object through the pattern.

Though the light design may perfectly correspond to the pattern, the light design is usually deformed due to: a) changeable direction of the external light, and b) changeable topography and placement of the object.

The non-uniform controllable pattern may be either constant or periodically appearing on the active surface. For example, the pattern may be periodically produced by controllably and selectively blocking specific pixels of the active surface. (It should be noted, that after determining specific problematic - glaring- areas of the active surface, the problematic areas will be blocked in the same or similar manner, by turning their pixels into opaque ones).

The pattern may be arranged so that, when external light passes through said surface with the non-uniform pattern and illuminates an object positioned behind the surface, a light design ( light/shade printout) of at least one portion of the pattern will appear on the object; said light design being respectively indicative of at least one specific area of said active surface which carries said at least one portion of the non-uniform pattern and which has currently guided the external light to the object.

The pattern may constitute a plurality of different symbols, for example digits, or combinations thereof, indicating different areas of the active surface.

Alternatively or in addition, the pattern may comprise a plurality of patterns and/or sub-patterns appearing in sequence on different areas of the active surface.

The method may comprise detection ( and further blocking) of the source of excessive light by the active surface, by analyzing light designs appearing on the object in response to said sequence of sub-patterns.

The proposed active surface, owing to its ability of non-uniform light guiding, allows dynamic detection of a light source, since it allows dynamic and comprehensive mapping of the light source on the object.

As mentioned above, the system comprises the camera monitoring the mapped light design on the object, a processor which receives data from the camera and controls the active surface to selectively block specific area(s) on the active surface which has(ve) currently passed/guided excessive external light to the object or to a critical part thereof.

In other words, when a light design, indicating a specific area of the active surface, is registered by a camera on the object (or at a critical location on the object), suitable data will be sent to a processor and the processor will determine whether that specific area of the active surface should be currently blocked (darkened), and if yes, will send a s command to the active surface.

For example, when intensity of light at the location of such a registered light design is higher than a predetermined threshold, the suitable area of the active surface may be blocked by the command from the processor (thus creating a light blocking/filtering "patch" on the active surface).

More than one portions of the pattern may be mapped on the object thus creating on the object a specific light design, and therefore more than one suitable areas of the active surface may be respectively blocked if light intensity of the mapped design is higher than allowed.

For example, multiple light sources may be detected and blocked simultaneously or one after another. For example, if more than one dazzling light source appears, the strongest one will generate the strongest design on the object; upon blocking the suitable area of the active surface, the next strongest dazzling light source will show its' design on the object and so on, until all the dazzling lights are blocked.

Brief description of the drawings.

Fig. la is a schematic pictorial presentation of one embodiment of a detecting light filtering active surface

Fig. lb is a schematic pictorial presentation of one embodiment of a light filtering and a light protective active surface.

Fig. lc is a pictorial presentation of one embodiment of the proposed system.

Figs. 2 shows examples of the proposed non-uniform light filtering pattern.

Figs. 3 a-f show examples of detecting light printouts (light design) on the face of a driver in one version of the proposed method, where different patterns/sub-patterns appear on the active surface .

Fig. 4 is another example of a non-uniform pattern for the proposed active surface. Fig. 5 is yet another exemplary pattern constituting a grid of digits forming different numbers placed at different areas of the active surface. Since the digits are different, the pattern is non-uniform, though is based on a uniform angular grid.

Detailed description of specific embodiments The invention will be further described in more details with reference to the following non-limiting drawings in which:

Fig. la schematically shows one embodiment of a light filtering, light detecting surface DS. Fig. la also shows an external light source S and an object O illuminated by the light source S through the surface DS . The DS may be active (controllable), which option is shown by the dashed control arrow "Control of DS". The DS surface has non-uniform transparency and serves as a non-uniform light guide for the light passing there-through. In this specific embodiment, the DS exhibits a non-uniform light-filtering pattern P. The pattern P may have various configurations. P may be permanent or may be controllably created on the DS. DS with a permanent pattern P may just carry non-transparent elements printed/deposited on DS.

A passive (not controllable) DS may, for example, be a transparent car windshield with deposited on it non-transparent elements forming a non-uniform pattern. If DS is active (controllable), and if P is controllably created on it, P may be static, dynamic or combined, for example periodically appearing, changing at different stages etc. When illuminated by external light, pattern P causes appearing a light design LD on the object O. Owing to non-uniformity of pattern P, the light design LD is indicative of specific area/s of the light detecting surface (DS), via which light has passed from source S to object O. In other words - LD being a light guide with non-uniform transparency, serves a tool for determining one or more specific areas A on itself (LD), passing light beams of the external source S.

Fig. lb schematically shows one embodiment of a combined light-filtering surface CS comprising a light detecting surface DS and a light protective surface PS.

In principle, the two surfaces DS, PS may be just two separate coatings or plates placed one onto another. In such a case DS may even be an inactive generally transparent member (for example, windshield's or visor's body) with a permanent non-uniform pattern P. However, since the DS and PS are placed one onto another, the non-uniform pattern P of DS can be considered part of PS.

In another embodiment, the two surfaces DS and PS may constitute one common light-filtering active surface CS having the described double function (i.e. capable of serving both for light detection and for light protection). In this case, DS (being a light filtering active surface) simultaneously constitutes a light-protective active surface PS capable of controllably regulating light conductivity/ transparency of its areas, depending on information about the specific area A determined owing to the non-uniform transparency of the DS. Control of DS may cause appearance of pattern P on the combined active surface CS . The light design LD appearing on the object O, will correspond to the specific pattern fragment characteristic for area A of the DS.

Based on recognition of the light design LD appearing on the object O, the protective active surface PS may be controlled. For example: if intensity of light, passed by the determined specific area A to the object, exceeds a predetermined threshold, it may mean that the light is dazzling/blaring. The light conductivity (transparency) of the determined area A may be decreased or even blocked to protect the object from the dazzling light. In Fig. lb, "Control of PS" causes darkening of the area A.

Fig. lc shows one specific embodiment 10 of the proposed system, where an example of a combined active light filtering surface (CS) 12 is placed on a windshield window of a car. A non-transparent conventional visor 13 may remain in the car ( in an alternative embodiment, visor 13 may constitute the active surface similar to 12). In this example, the object to be protected from dazzling light is the driver's 14 eye region. The active surface 12 may be integral with the windshield or be separately installed, may cover part of the window or the whole window. The exemplary system 10 further comprises:

• A camera 18 looking at the face of a user (a driver) to monitor it.

• A processor 20 connected to the camera and to the active surface 12.

• The active light-filtering surface/screen 12 installed in front of the driver's eyes and exhibiting a non-uniform, permanent or controllable, static or dynamic light-filtering pattern 16. In this example, it comprises three different sub-patterns 16a , 16b and 16c, located at different portions of the surface 12 ( the sub-patterns are symbolically divided with thin lines)

The active light- filtering surface/screen 12 may be normally transparent, the sub- patterns 16a- 16c may be controllably created in the screen 12 when the anti-dazzling system is ON, say due to presence of dazzling light(s) 15. The system may be switched on automatically, when excessive intensity of light is detected by the camera 18. Based on the light design 17 and its intensity detected by the camera 18 on the eye region of the driver 14, the processor 20 can determine and selectively darken those specific area/s 22 of the active surface 12, which guided excessive light to the object, thus protecting the driver from being blinded by the sun or other strong light sources 15.

In other words, the processor uses the active screen 12 both as a means for detecting (and further tracking) of the dazzling lights (by mapping their light on the object and determining areas of the screen which conduct/guide the most hazardous light), and as means for dynamically blocking those areas, thus optimizing the blocking area size and location.

The process is dynamic.

One example of the process may comprise the following steps.

The system 10 detects dazzling lights 15 which are directed to the driver's eyes, by analyzing a picture (design) 17 on the driver's face, which is created by the light filtered through a pattern 16 on the active screen 12. For example, an exemplary pattern 16 may be generated on the active surface 12 for a very short instant. If such a design 17 is detected, approximate location of area/s to be blocked on the screen 12 may already be determined. Other or additional (for example, static or dynamic, more accurate or more schematic) patterns may be generated to determine such areas and, consequently, the optimal location and shape of the blocking patch(es) 22.

The camera 16 keeps the monitoring function andthe processor 20 keeps the detection/determining function even after creating patch/es 22 , so that the location and shape of the patch/patches 22 follows movements of the driver and /or of the dazzling lights.

All steps are performed automatically and the blocking is removed when the dazzling light disappears.

One can readily note the following advantages of the invention: all measurements are defined by the patterns 16 of the active screen 12, precise installation of the camera 18 is not needed, no assessment of the eyes location is required and no three parallax compensation is necessary. The system is simple and aesthetic; the active surface - in this embodiment part of a windshield or a visor - is normally transparent and does not disturb the user.

Another exemplary version of the method.

The method may comprise two phases:

• Turn on phase - at this phase the camera 18 detects excessive light on the driver's face and starts searching/ tracking the face of the driver and specifically the driver's eyes. This phase continues in parallel with the next phase.

• Periodic operation phase - may consist of several periodic steps.

Each step begins with a brief display of a controllable light-filtering pattern on the active screen, sufficiently brief so as not to be noticed by the driver.

The display is synchronized with the camera so that the design of light generated by the dazzling light on the face of the driver, is captured by the camera and analyzed by the processor.

The steps are periodically repeated and are as follows:

Detect and count dazzling lights 15 using the mapped design 17 on the driver's face.

Determine areas of the active screen 12, which conduct/guide the dazzling light to the eyes region

Block the determined areas & track the dazzling lights relative to the eyes region (i.e., repeating the two preceding steps).

It should be noted that there is a step of un-blocking the blocked areas when the dazzling light disappears or does not affect the driver's eye region anymore.

In Figures 2a-2e one can see an example of the patterns/sub-patterns sequence which may be generated on the active surface 12 of a visor or windshield. The sequence may be used to detect, allocate and block a source of dazzling light.

The top pattern (Fig. 2a) is used to detect and count the dazzling lights. Search will be started only if the light(s) presence is detected. This is based on a predetermined threshold value of light intensity on the object ( in this example, the user's eye region). The axes are just for illustration, they are not a part of the pattern. Further patterns (Figs. 2b-2e) are examples of partial patterns (sub-patterns) which enable more accurate measurements of the dazzling light's direction and more optimal blocking of critical areas of the active surface. The exemplary pattern 2a consists of an entirely dark visor in which a number of small holes enable penetration of the dazzling light. These holes act as a well- known Camera Obscura. When a strong light illuminates a hole, a lighted spot appears on the background, in this case we are interested in the lighted spots appearing on or near the eyes region on the face of the driver. The camera detects these spots ( being part of the light "design") and the processor 20 generates a next pattern (say, 2b) on the visor. It is done to further improve allocation of the visor's area to be blocked, and to decrease the size of the blocking spot.

More than one spot can appear even if only one light exists, because several adjacent holes may be illuminated.

However if more than one light exists, we will see several groups of spots on the face of the driver.

Each group will be handled and eventually blocked.

At this step, the pattern 2a is such that holes will exist on only a part - say the left half - of the darkened visor. It may be called a sub-pattern. If the spots appear again this means that the light comes from this direction, this search will continue in this way, using a sequence of other sub-patterns, until the spot location and its primary shape is defined.

At this stage, blocking of the area of the active surface 12, where the spot has been located, will start but the search function will continue to optimize the shape and the location of the blocking area (even if the location of the eyes or the direction of the light has changed).

The search function may continue by applying sub-patterns 2c, 2d, 2e to further clarify the position of the dazzling light and to optimize the shape and the location of the blocking patch to be created. According to logics of this exemplary search, the patch will be created at the lower left-central portion (2e) of the active surface.

For glaring lights which have moved away from the field of view, the previously created blocking may be removed. The exemplary patterns shown in Fig. 2 are "Polar" patterns arranged approximately opposite the center of the eyes region of the driver and spaced so that the typical angular spacing is a constant being slightly smaller than the typical of the angular aperture of the expected dazzling lights (About 0.5° for the sun). The center of this pattern can be adjusted by the system 10 to match the location of the driver's face as measured by the system camera 18.

However, a simpler - e.g. Cartesian - grid can be used as well.

As has been mentioned, Figs 2a-2a illustrate an example of filtering the dazzling lights based on the well-known method of "Camera Obscura" (CO). According to CO, the entire active screen is darkened while a number of transparent holes will create a pattern of lighted spots on the object, corresponding to the directions from which the light is currently coming.

In the CO implementation, the size of the holes is determined by the expected amount of light required to generate an easily detectable illuminated spot on the face of the driver. This may mean that holes remote from the face will be somewhat larger than those near the eyes.

It should be noted, however, that Figs. 2a-2e may also be understood as illustrating an opposite principle of Camera Illuminata (CI). Just, it has to be taken into account that according to CI, implementation the entire screen remains clear while a static or dynamic non-uniform pattern of dark elements is displayed on the screen. In one particular embodiment such dark elements may be a plurality of spots. The pattern may be similar but negative to the patterns of Figs.2a-e, or have another non-uniform configuration.

In practice, at each stage of the process (i.e. - the Detect & Count, Mapping and Block and Track) a pattern of dark elements is displayed on the screen. The pattern may change from stage to stage, and may change dynamically during one stage. The principle remains the same: when a dazzling light appears, it will pass through a portion of the screen, and the pattern appearing on this portion will appear on the face of the driver (as a corresponding light design having high light intensity).

As most of the screen is clear in the CI implementation, a larger area will be reflected illuminated, the user will feel more comfortable with the sight of view, and thus it would bo "easier" for the processor of the system may more effectively determine the location of regions(s) on the active screen where the light passed to illuminate the driver's face.

The system proposed by the Inventors (for example, 10 of Fig. 1) may have further features and advantages:

1. Use of an active surface/screen and a single camera monitoring the object, both loosely installed (no precise or robust installation required), to optimally perform all protection functions.

2. Different patterns may be used for each stage of the process, namely to:

a. Detecting appearance of dazzling source(s)

b. Allocating dazzling source(s)

c. Blocking dazzling source(s)

d. Tracking dazzling source (s)

e. Detecting disappearance of dazzling source (s) and removing the blockage.

3. Using the camera to compensate for dynamic changes (during the tracking stage), because of motion of the external light source or motion of the object.

4. Synchronizing appearance of different patterns with camera scans to optimize search time ( and to minimize blockage time of the field of view).

5. Continuing the search and the optimization even after the blockage has started.

6. Use of various location & blockage patterns adapted to a single dazzler, multiple dazzlers, diffuse dazzler or concentrated dazzler, strong or weak dazzler.

Use of dynamic light-filtering patterns, synchronized with the camera and the processor.

Figs 3a-3f illustrate how different patterns generated on the active surface 12 may be used for searching and detecting the dazzling spot, and for determining a blocking area to be created on/removed from the active surface, by recognizing a correspondent light design 17a- 17f on the driver's (14) face. The system for implementing the proposed method may incorporate any commercially available software for face recognition. It is kept in mind that light printouts on the object (the driver's face or eye region) are called "design", and they are formed by light passing through a pattern on the active surface 12 . The dazzling light spot is schematically indicated by a light oval ( and marked *) on the active surface 12. The area of the surface, which includes the dazzling spot, should be determined and further blocked ( similarly to area "A" in Figs, la, lb or areas 22 in Fig. lc).

Figs 3a-3d refer to different patterns generated in the active surface 12 during the search and the determining stages of the method. In this example, patterns of Figs. 2a- 2d are used. The figures 3a-3d also refer to different light designs 17a- 17d on the driver's face 14, resulting from those different patterns.

Fig. 3e refers to the step of blocking a specific area in the active surface 12, based on the search and the determining process shown by Figs. 3a-3d. A blocking patch 22-A, created on the surface 12, covers the determined area (22-A) which includes the dazzling light spot (*). The eye region of the driver 14 is now free from light spots; to the contrary, it is completely shadowed ( see the light design 17e being the shadow). Fig. 3f illustrates a step of tracking of a light source, using an example of monitoring the driver's head movement. In case the system detects that the blocking patch 22-A of the active surface/visor 12 does not protect the eye region anymore (regardless whether the eye region is illuminated or not), the useless blocking patch 22-A will be then removed. The situation can be detected, for example, when the light design ( actually, the shadow 17e) corresponding to the blocking patch 22-A is shifted from the eye region and is placed at an irrelevant portion of the driver's face ( in our example, on the driver's nose). In case a new light design 17f at the eye region, which is permanently tracked by the system, becomes excessively illuminated (not shown in this figure), another blocking patch will be created.

Fig. 4, Fig. 5 show some non-limiting examples of other solutions for the nonuniform light filtering pattern proposed in the invention.

For example, peripheral sub-patterns may be larger ( more spaced) than the central ones.

The light-filtering pattern may comprise any non-uniform system of non-transparent elements, for example a polar system 30 or a grid 40 of different non-transparent (dark) numbers. The purpose is that the non-transparent elements indicate different areas of the active surface 12. The non-transparent elements of system 30 may have various shapes ( not shown in the figure). It will be quite simple to recognize light designs of such numbers on the object (say, on the driver's face).

In yet another example, the non-uniform pattern may be dynamic and be synchronized with the camera and the processor.

Multiple dazzling lights may be blocked successively or in parallel.

For example, if more than one dazzling light appears, the strongest one will generate the strongest design fragment on the driver's face, and when this strongest light is blocked, the next strongest light will show its' design and so on, until all the dazzling lights are blocked and tracked. Alternatively, all fragments of the design having light intensity higher than a predetermined threshold, may be processed in parallel by the processor and cause parallel blocking of the multiple dazzling lights.

Though the present invention has been described with reference to a limited number of some exemplary embodiments and versions, it should be appreciated that other implementations of the system and versions of the method may exist and should be considered part of the invention, whenever covered by the claims which follow.

Claims

Claims:
1. A tool for detecting a light source illuminating an object, the tool comprises a light detecting surface being a light filtering surface adapted to exhibit non-uniform transparency over said surface in such a manner that, when placed between the object and said light source, the light filtering surface allows determining a specific area thereof which currently passes more light from the light source to the object, than other areas of said light filtering surface.
2. The tool according to Claim 1, wherein said light detecting surface is either a passive, non-controllable light-filtering surface or an active, controllable light filtering surface.
3. The tool according to Claim 1 or Claim 2, wherein the light detecting surface is capable of exhibiting the non-uniform transparency in place and/or in time, and is thereby capable of mapping light of said light source on said object in such a manner, that design of the mapped light allows recognizing said specific area.
4. The tool according to any one of the preceding claims, wherein the light detecting surface is adapted to exhibit a non-uniform light-filtering pattern.
5. The tool according to any one of the preceding claims, further comprising a light regulating, active light filtering surface, and being adapted to controllably regulate transparency of the determined specific area by controlling said light regulating surface.
6. The tool according to Claim 5, wherein said light detecting surface and said light regulating surface are one and the same light filtering active surface capable of controllably and selectively changing transparency of the determined specific area.
7. The tool according to Claim 5, adapted to controllably decrease transparency of said determined specific area, whenever intensity of the light passed by said area to the object exceeds a predetermined threshold.
8. The tool according to Claim 4, wherein the non-uniform pattern is formed by transparent and non-transparent elements of the surface, said non-uniformity of the pattern being such that different areas of the surface are distinguishable by local fragments of the pattern placed on such different areas.
9. The tool according to Claim 4, wherein the light detecting surface is an active light-filtering surface controllable to exhibit said non-uniform pattern.
10. The tool according to Claim 9, wherein said non-uniform pattern is static, dynamic or combined.
11. The tool according to Claim 9, wherein said non-uniform pattern is periodically produced by controllably and selectively regulating transparency of said surface.
12. The tool according to Claim 4 or 8, wherein said non-uniform pattern constitutes a plurality of different digits, symbols or combinations thereof, indicating different areas of the surface.
13. The tool according to Claim 9, wherein said non-uniform pattern comprises a plurality of patterns and/or sub-patterns appearing in sequence on different areas of said surface.
14. The tool according to any one of the preceding claims, being part of at least one of the following: a vehicle windshield, a vehicle visor, sunglasses, a visor of a headset, a piece of headwear, a shield for an optical device.
15. A system comprising the tool according to Claim 1.
16. The system according to Claim 15, comprising:
-a first light filtering surface constituting the light detecting surface,
- a second light filtering surface constituting an active light regulating surface, wherein said first and second surfaces
being either placed in close proximity to one another, or constituting a common active light filtering surface, and
being positioned between the object and the light source;
- a camera for monitoring the object illuminated via said first and second surfaces, - a processor for
receiving and processing data from the camera,
determining, based on the data, the specific area of the first surface passing more light to the object than other areas of the first surface, and
controlling the second surface to selectively regulate transparency of a region thereof, corresponding to the determined specific area of the first surface.
17. The system according to Claim 16, wherein the first surface and the second surface constitute a common active light-filtering surface,
and wherein the processor is adapted to control said common surface to controllably exhibit a non-uniform light filtering pattern for mapping a light design on the object, and further adapted to process the data on said light design, obtained from said camera.
18. The system according to Claim 17, capable of synchronizing exhibition of the light-filtering pattern with the camera period, so as to minimize time required for detection of the light design created by said pattern on the object.
19. A method for detecting light source illuminating an object, by using the tool according to Claim 1.
20. The method according to Claim 19, comprising the following steps: ensuring that said tool, exhibiting non-uniform transparency over the light detecting surface, is positioned between the light source and the object, getting the object illuminated by the light source through the tool,
obtaining a light design on the object, resulting from mapping light on the object by the tool,
determining the specific area of the detecting surface, currently passing more light than other areas of the tool, by detecting on said object at least one fragment of the light design, indicative of said specific area.
21. The method according to Claim 20, comprising a step of regulating intensity of light mapped on the object, by using the tool comprising a light regulating active surface and by controlling transparency of said light regulating active surface at a region corresponding to said determined specific area of the light detecting surface.
22. The method according to Claim 21, wherein the step of regulating intensity is performed for protecting the object from dazzling light of said light source, and comprises:
controllably blocking said region of the light regulating active surface, whenever intensity of said at least one light design fragment exceeds a predetermined threshold.
23. The method according to Claim 21, comprising controllably creating a static, dynamic or combined non-uniform light filtering pattern in the light detecting active surface, for further mapping light onto the object.
24. The method according to Claim 23 wherein the step of creating said nonuniform light filtering pattern is performed in synchronization with the step of obtaining the light design on the object.
25. The method according to Claim 22, further comprising:
a step of tracking the light source by monitoring said light design on the object, and based on the monitoring results, deciding whether to keep blocked the previously blocked area, to unblock the previously blocked area, and/or to block another area.
26. The method according to Claim 22, comprising detecting and blocking more than one light sources.
27. The method according to Claim 22, comprising adjusting borders and/or square of the determined area to compensate relative movement of the dazzling light source with respect to the object.
28. A software product comprising computer implementable instructions and/or data for carrying out the method according to Claim 19, the software product being stored on an appropriate non-transitory computer readable storage medium so that the software is capable of enabling operations of said method when used in a computerized system.
PCT/IL2017/050083 2016-01-25 2017-01-22 Technique for detecting a light source illuminating an object WO2017130188A1 (en)

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