FR3045133A1 - LIGHTING DEVICE AND METHOD FOR MANUFACTURING A PATCH OF SUCH A DEVICE - Google Patents

Abstract

The invention relates to a lighting device for a person comprising at least one lighting assembly (2) comprising a lighting column (11) extending vertically and at least one light source (12) arranged at the level of the base of the column and configured to generate light waves propagating in the column, the column comprising at least one diffusing patch (21, 22, 23) arranged inside the column so as to be inclined relative to the direction propagation of said light waves, the patch being configured to pass a portion of the light waves towards the top (15) of the column. The invention also relates to a method for manufacturing a patch of a lighting column of such a lighting device.

Description

1 / invention relates to a lighting device for capturing an image of a person including, although not exclusively, a lighting device for capturing an image of a person's face. The invention also relates to a method for manufacturing a patch of such a device.

BACKGROUND OF THE INVENTION

In the field of image acquisition for biometric identity documents, facial lighting plays a key role in optimizing the quality of images acquired. Indeed, the lighting makes it possible to avoid that the images include reflections on the glasses, areas of saturation on the skin ... In parallel, the lighting must however avoid dazzling the person illuminated while being sufficiently intense to be robust to parasitic light sources (lighting of the ambient environment, the sun, etc.).

Because of all these requirements, few solutions are currently available for the acquisition of good quality images. Photobooths or photo studios are usually known, which are usually equipped with several flashlights associated with retro-diffusing umbrellas or with large diffusing surfaces. However, these devices and equipment are bulky and impractical to move. In addition, these devices and equipment ultimately deliver a paper print that must then be scanned which generates damage. Thus, the current systems of facial recognition can not be based on this type of images.

To overcome these disadvantages, it has been envisaged to illuminate the face of a person using two fluorescent tubes.

However, this type of device proves relatively expensive. Indeed, the fluorescent tubes are not only greedy in electrical energy but also have a short life.

OBJECT OF 1 / INVENTION

An object of the invention is to provide a lighting device for image capture of a person that is of less cost and less space. An object of the invention is also to provide a method of manufacturing a patch of such a lighting device.

BRIEF DESCRIPTION OF THE INVENTION

With a view to achieving this object, a lighting device for capturing an image of a person comprising at least one lighting assembly comprising a vertically extending lighting column and at least one light source arranged at the column base level and configured to generate light waves propagating in the column, the column including at least one diffusing patch arranged inside the column so as to be inclined relative to the direction of propagation of said light waves , the patch being configured to pass a portion of the light waves towards the top of the column.

Thus, the column acts as a guide of the waves injected by the light source in the column: the light, trapped in the column, comes out of the column diffuse manner thanks to the presence of the diffusion patch placed inside the column . The inclination of the patch also makes it possible to direct the light in a preferred zone determined by the angle of inclination of the patch vis-à-vis the direction of propagation of the light waves.

The lighting device thus makes it possible to provide a very good quality of lighting while remaining little dazzling for the person since it generates a diffuse light.

Such a lighting device is therefore simple structure which makes it inexpensive. In particular, this lighting device makes it possible to dispense with the fluorescent tubes of the prior art. In addition, such a device is relatively compact.

For the whole of the present application, a "patch" is an optical device for transmitting to the rest of the column a portion of the light waves generated by the light source and striking said patch, while reflecting by diffusion another part of said waves to allow the transmission of diffuse reflected waves outside the column.

Of course, in the present application, the terms "upper", "lower", "horizontal", "vertical" must be understood according to the direction of use of the lighting device and in particular of the associated assembly. The direction of use is therefore that in which the column rests on the ground or on a support, the light source being at ground level or support.

By "direction of propagation" is meant the direction in which all or almost all light waves are propagated by the light source.

By "density" of a patch, here is meant the percentage of opacity of the patch. The "density" of a patch can therefore also be defined as being the result of 100% - the light transmittance (which is a percentage characterizing the amount of light transmitted). Therefore, a patch having a density of 100% (i.e., being 100% opaque) does not let any light wave pass through it and a patch having a density of 0% (i.e. being 0% opaque) lets 100% of the light waves pass through it. The invention also relates to a method for manufacturing a patch of a lighting column of a device as previously described comprising the steps of: cutting into at least two blocks the column, each of the blocks having a corresponding beveled face to that of the other block, apply a layer of reflective or diffusing material on one or both beveled faces, affix the two bevelled faces one against the other, and connect the two bevelled faces one to one 'other.

BRIEF DESCRIPTION OF THE DRAWINGS The invention will be better understood in the light of the following description of non-limiting embodiments of the invention with reference to the attached figures, in which: FIG. 1 is a schematic top view of the invention; lighting device according to a first embodiment in position with respect to a person and an image acquisition system of the person, - Figure 2 is a side view of one of the sets 1 is a perspective view of a lighting column of a lighting device according to a second embodiment of the invention, FIG. a side view of one of the lighting assemblies of the device according to a third embodiment of the invention.

DETAILED DESCRIPTION OF THE INVENTION

Referring to Figures 1 and 2, the lighting device according to the first embodiment of the invention, generally designated 1, is here shaped to illuminate the face V of a person. The lighting device 1 is here used to illuminate the face V of a person to allow acquisition of an image of said face V by an image acquisition system S, so that the image V can be used for biometric identity documents. This application is of course not limiting and we can associate the lighting device 1 to other systems as a facial recognition system.

Here, the lighting device 1 comprises a first lighting assembly 2 comprising a first lighting column 11 and a first light source 12 associated with the first lighting column 11, and a second lighting assembly 3 comprising a second lighting column (not referenced here) and a second light source (not referenced here) associated with the second lighting column. The two sets 2, 3 are here identical to each other.

The two sets 2, 3 are shaped so that the two columns each extend vertically. Preferably, the two sets 2, 3 are shaped so that they can each be arranged on a Su medium such as a table, desk or console. In this way, the lighting device 1 proves to be at a height sufficient to frame the face V of the person, regardless of the size of the person, without having to extend from the ground which would complicate its manufacture and increase its cost.

Preferably, the two sets 2, 3 are arranged on either side of the face V of the person symmetrically with respect to said face V. In addition, the two sets are arranged symmetrically with respect to the acquisition system. images.

This minimizes the presence of reflections on the glasses and gradients on the sides of the face V.

Each set 2, 3 is thus arranged at the same distance from the face V and the two sets 2, 3 are each arranged at the same angle delimited on the one hand by the segment 13 connecting the two sets and on the other hand a segment connecting the whole considered to the person. Preferably, this angle a is between 40 and 50 degrees. Typically this angle is 45 degrees.

This further minimizes the presence of reflections on the glasses possibly worn by the person or reflections on the face V of the person.

Preferably, the two sets 2, 3 are arranged so that the middle of the segment 13 connecting the two sets is at a distance d from the face V between 40 and 60% of the length of said segment 13. Typically, the two sets 2, 3 are arranged so that the middle of the segment 13 is at a distance d from the face of approximately 50% of the length of said segment 13.

This improves the illumination of the face V of the person.

Moreover, the two sets 2, 3 are arranged so that the middle of the segment 13 connecting the two sets 2, 3 is at a distance from the image acquisition system S between 40 and 60% of the length of said segment 13. Typically, the two sets 2, 3 are arranged so that the middle of the segment 13 is at a distance 1 from the image acquisition system S of about 50% of the length of said segment 13.

This makes it possible to further improve the lighting of the face V, which is thus illuminated in a substantially identical manner on both sides.

The first set 2 will now be described. The second set 3 here being identical to the first set 2, the following description also applies to the second set 3.

The first light source 12 is arranged at the base of the first column 11 and configured to generate light waves propagating in the first column 11 here in a direction of propagation of light waves substantially identical to the direction X which extends the first column. In particular, the first column 11 has a bore within which the first light source 12 is arranged which is closed by a cover so that the first column 11 and the first light source 12 are thus secured to each other. the other. The first set 2 thus forms a unitary whole more easily transportable.

Preferably, the first light source 12 comprises a single light-emitting diode 14.

Preferably, the first set 2 comprises heat dissipation means (not shown here) associated with the light emitting diode 14 to limit heating at the base of the first column 11.

Preferably, the light-emitting diode 14 is flat. The light-emitting diode 14 is here shaped so as to have an emission cone of between 45 degrees and 90 degrees.

The first column 11 is a solid block which is transparent here. The first column 11 is for example glass, especially glass extra-white quality, crystal or even polymer such as a polymer based on polymethyl methacrylate.

The first column 11 comprises in particular three diffusing patches each arranged entirely inside the first column 11.

Each patch is here shaped in a plane.

Preferably, each patch is uniform and homogeneous, that is to say that it has no particular pattern.

The first patch 21, which is the patch closest to the base of the first column 11 and therefore of the first light source 12, is configured to pass a portion of the light waves towards the top 15 of the column and therefore the two other patches. Similarly, the second patch 22, which is the central patch, is configured to pass a portion of the light waves to the top 15 of the first column 11 and the third patch 23. The third patch 23, which is the patch the closest to the top 15 of the first column 11 and therefore the farthest from the first light source 12, is here also configured to let part of the light waves to the top 15 of the first column 11.

Preferably, each patch is shaped to have a density at least greater than that of the patch beneath it. In this way plus a patch is removed from the first light source 12 plus it is shaped to have a high density. This allows the patches closest to the first light source 12 to pass a significant portion of the light waves (typically at least 40% of the light waves and preferably at least 50%) to the higher patches.

This improves the uniformity of the light diffused by the first set 2.

In this way, the first patch 21 is here shaped to have a density identical to that of the second patch 22. The third patch 23 is here shaped to have a density strictly greater than that of the first patch 21. The first patch 21 and the second patch 22 have a density of between 40% and 60% (ie between 60% and 40% respectively of the light waves affecting the first patch 21, respectively the second patch 22, are transmitted in the direction of the second patch 22, respectively the third patch 23) and the third patch 23 has a density of between 0% and 10% (that is to say between 10 and 0% respectively of the light waves affecting the third patch 23 are transmitted towards the summit 15). Typically the first patch 21 and the second patch 22 have a density of about 50% (i.e., about 50% of the light waves affecting the first patch 21, respectively the second patch 22, are transmitted in the the second patch 22, respectively the third patch 23) and the third patch 23 has a density of about 95% (i.e., about 5% of the light waves affecting the third patch 23 are transmitted towards the summit 15).

In addition, each of the patches is arranged so as to be inclined relative to the direction of propagation of the light waves.

Thus, preferably, the second patch 22 is arranged to be more inclined relative to the direction of propagation than the first patch 21 and the third patch 23. The second patch 22 typically has an inclination at least twice that of of the first patch 21 and the third patch 23. Here the first patch 21 and the third patch 23 have the same inclination relative to the direction of propagation. The three patches are all inclined in the same direction.

The first patch 21 and the third patch 23 have for example an inclination of between 15 and 25 degrees and the second patch 22 has an inclination of between 40 and 50 degrees while being at least twice as large as that of the first patch 21 and the third patch 23. Typically the first patch 21 and the third patch 23 have an inclination of 20 degrees and the second patch 22 has an inclination of 45 degrees.

In particular, the different patches are arranged in the first column 11 so that the middle of each patch is arranged in the upper half of the first column 11. This makes it possible to further improve the illumination diffused by the first column 11 .

Moreover, the middle of the first patch 21 and the middle of the third patch 23 are equidistant from the middle of the second patch 22. This makes it possible to further improve the illumination.

Preferably, each patch comprises a layer of material arranged inside the first column 11. The layer of material is here uniform and homogeneous over the entire surface of the corresponding patch. The layer of material is here diffusing (in this case the value 0% is excluded for the density of the third patch 23). The layer of diffusing material is for example white paint or white ink for which it is possible to adjust the level of light transmission (for example by playing on the thickness of the layer or on the color itself) , which gives the possibility of obtaining different possible densities for the different patches.

Typically, the first column 11 is cut into several blocks having corresponding planar bevel faces. Each layer of diffusing material is then applied (by painting, by printing, etc.) on one or both beveled faces facing each other. Then the two bevelled faces are affixed against each other and are connected to each other (by welding, gluing ...). This makes it possible to reform the first complete unitary column 11.

Patches are thus implanted inside the first column 11 in a simple and fast manner.

Note that it is furthermore easy to choose the inclination of the patch when cutting the first column 11 into different blocks.

The first set 2 has just been described. Again this description applies to the second set 3.

Thus, the lighting columns of the lighting device 1 serve as waveguides. The light, trapped in each lighting column, emerges from the associated lighting column in a uniform and oriented manner thanks to the presence of the different patches. The lighting device 1 offers a good quality of lighting by diffusing in particular a homogeneous light on the face and whatever the size of the person. In addition, the light is diffused which prevents him from being too dazzling for the person. Preferably, the power of the light-emitting diode is adjusted to obtain average illumination at the face of the person by the lighting device of about 600 Lux.

In addition, the lighting device 1 proves relatively simple and inexpensive in particular because a single light-emitting diode is sufficient here for each column, the light-emitting diodes having the advantages of having a good life while being low energy consumers. Light-emitting diodes furthermore have the advantage of being able to be switched on rapidly. In addition, the light-emitting diodes are easily controllable, the setting of the emission power of the light-emitting diodes being easy and almost instantaneous.

With reference to FIG. 3, a second embodiment will now be described.

The lighting device of the second embodiment is identical to the lighting device of the first embodiment, with the difference that the first patch 121 and the second patch 122 of each column do not have a uniform and uniform surface, but contrary to the reasons. The first patch 121 and the second patch 122 thus comprise here a layer of material which is not uniform but instead forms patterns. The layer of material is here reflective (that is to say 100% opaque) while the holes in the patch delimited by the patterns of said layer are of course 0% opaque. The holes are for example circular in shape so that the first patch 121 and the second patch 122 have a grid shape.

The first patch 121 and the second patch 122 are here arranged so as to have an equivalent density vis-à-vis the first embodiment.

In particular here, the third patch 123 remains uniform and homogeneous (that is to say does not present patterns). The third patch 123 is arranged to have a density identical to that of the first embodiment.

In this way, the more a patch is removed from the base of the column, the more it is shaped to have a high density. This makes it possible to improve the uniformity of the light diffused by the lighting device.

So we can see that we can play on the geometry of the patterns to define the density of a patch as well as the characteristics of the patch material layer (thickness, color ...).

With reference to FIG. 4, a third embodiment will now be described.

The lighting device of the third embodiment is identical to the lighting device of the first embodiment, with the difference that the different patches 221, 222, 223 are not flat but curved. The different patches 221, 222, 223 are here curved towards the base of the associated column.

This makes it possible to diffuse the light differently by the lighting device.

Naturally, the invention is not limited to the embodiments described and variations can be made without departing from the scope of the invention as defined by the claims.

In particular, the lighting device may have only one set of lighting. : 1:::

The two sets of lighting may be different from each other for example at the light source and / or at the level of the lighting column.

Although here the different lighting columns are completely transparent, a column may include one or more areas more opaque or completely opaque. It may also depolish part or all of the column to change the diffusion of light waves at this level. The column may include localized an outer coating (reflective or diffusing paint type) to modify the diffusion of light waves.

Each column may comprise a number of diffusing patches different from what has been indicated, provided that at least one of them is included.

Each patch may be different from what has been indicated in terms of size, shape, density, inclination relative to the direction of propagation and / or positioning in the associated column relative to said column and / or to the other possible patches of said column. This will help to gauge the intensity level of the light scattered by the associated lighting assembly as well as the uniformity of this light. We can for example play on the thickness, transparency and / or on the present patterns (dimensions, positions and / or number of patterns) on the patch to change the density. The different patches may be identical to each other or different.

Although here the patches are made from a layer of diffusing or reflective material, the patches can be made otherwise for example by grinding, sandblasting or laser etching of the column. In addition, when the patch comprises a layer of reflective material or diffusing, it may be other than white paint or white ink such as a diffusing film commonly used in photometry or photography, possibly cut to draw motifs. Each of the bevelled faces may of course be covered with a different material to form the layer of diffusing or reflective material and / or only one face may be covered.

In addition, although here the patches are white, the patches may be partially or completely colored (for example by using a colored material like colored ink and / or fluorochrome). This will change the color temperature of the light waves generated by the light source.

Moreover, the vertex may be formed directly by a diffusing patch such as that arranged inside the associated column.

Each column may include means other than the patch (s) diffusing (s) to transmit the light outside the column such as a cutout in the column or an etching spared column.

Each column may be associated with a larger number of light sources.

Each light source may be different from what has been indicated. Thus, each light source may include a different number of light emitting diodes than indicated. In addition, the light-emitting diode may be dome-shaped and not flat.

The light source may be arranged outside the column. The light source will then for example be arranged at the base of the column.

Although here the light sources are configured to work in continuous mode (that is to say they generate the light waves continuously), at least one of said sources can be configured to work alternately mode including flashed way. Preferably, at least one of the light sources will be configured so that it can work in both continuous mode and alternating mode.

Moreover, although here the light sources are configured to emit wavelength light waves belonging to the visible spectrum of the white light type, at least one of the light sources can be configured to work in another domain so that to generate light waves of a particular color of the visible spectrum, light waves of wavelength belonging to the infrared domain, the ultraviolet domain ... Preferably, at least one of the sources will be configured so as to ability to work alternately or simultaneously in different areas of the electromagnetic spectrum. It will be possible to switch between two particular colors (for example green light scattering or red light scattering) to develop a light protocol via the lighting device: for example green light diffusion when the person is correctly placed vis-à-vis of the lighting device and red light scattering in the opposite case.

If the lighting device comprises at least two lighting assemblies, the light sources of these lighting assemblies can be configured to work simultaneously or alternately in different or identical areas of the electromagnetic spectrum.

In the case where a particular temperature of the lighting will have to be respected, it will be possible to play on the type of light source used (emission of waves at a particular color temperature), on the type of patch used (colored or not) and / or on the accessory use of a colored film arranged in the column for example above the light source. :

Claims (13)

1. A lighting device (1) for capturing an image of a person comprising at least one lighting assembly (2, 3) comprising a lighting column (11) extending vertically and at least one light source (12) arranged at the base of the column and configured to generate light waves propagating in the column, the column including at least one diffusing patch (21, 22, 23; 121, 122, 123; 221, 222, 223) arranged inside the column so as to be inclined relative to the direction of propagation of said light waves, the patch being configured to pass a portion of the light waves towards the top (15) of the column. 2. Lighting device according to claim 1, wherein the device comprises a first lighting assembly (2) comprising a first lighting column (11) and at least a first light source (12) associated with the first column. a lighting unit (11) and a second lighting assembly (3) comprising a second lighting column and at least a second light source associated with the second lighting column. 3. Device according to claim 2, wherein the two sets (2, 3) are identical to each other. 4. Device according to one of claims 2 or 3, wherein the two sets are arranged symmetrically with respect to an image acquisition system and / or facial recognition. 5. Device according to one of the preceding claims, wherein the column (11) has a bore inside which is arranged the light source (12). 6. Device according to one of the preceding claims, wherein the light source (12) comprises a single light emitting diode (14). ; 7. Device according to one of the preceding claims, wherein the patch (21, 22, 23; 121, 122, 123) is plane. 8. Device according to one of the preceding claims, wherein the patch (21, 22, 23; 221, 222, 223) is uniform and homogeneous. 9. Device according to one of the preceding claims, wherein the patch (21, 22, 23; 221, 222, 223) is white. 10. Device according to one of the preceding claims, wherein the middle of the patch (21, 22, 23; 121, 122, 123; 221, 222, 223) is in the upper half of the column (11). 11. Device according to one of the preceding claims, wherein the column (11) comprises at least two patches (21, 22, 23; 121, 122, 123; 221, 222, 223). The device of claim 10 wherein each patch (21,22,23; 121,122,123; 221,222,223) is shaped to have a density at least greater than that of the patch beneath it. 13. A method of manufacturing a patch of a lighting column of a device according to one of the preceding claims, comprising the steps of: cutting into at least two blocks the column, each of the blocks having a corresponding beveled face to that of the other block, apply a layer of reflective or diffusing material on one or both beveled faces, affix the two bevelled faces one against the other, and join the two bevelled faces one to one 'other.