System for characterizing a material or matter of an object or moving body and associated object collection or sorting installation

Abstract

Characterization system (1) for characterizing a material or matter of an object or body in motion, comprising a measuring chamber (12) having a reflective wall (3) capable of reflecting radar waves and a support wall on which a radar wave transmitter / receiver device (5) is mounted, wherein the reflective wall has a general shape of a concave trough and has a main cross-section which passes through the radar wave transmitter / receiver device and which is inscribed in an ellipse having a first focus (81) and a second focus (82), and an ellipse axis (80) passing through the first focus and the second focus; and the first focus is positioned on the radar wave transmitter / receiver device and the second focus is positioned inside the reflective wall. Abstract Figure: Figure 8

Description

Title of the invention: System for characterizing a material or matter of an object or body in motion and associated installation for collecting or sorting objects Technical field

[0001] The invention relates to a characterization system for characterizing a material or matter of an object or body, and in particular an object or body in motion.

[0002] The invention finds a preferred, and non-limiting, application for characterizing the materials of objects which are waste, in particular in a waste collection or sorting installation.

[0003] Other applications are however conceivable, such as for example the characterization of materials of objects other than waste such as the contents of parcels, bags or luggage in terms of security, or parts circulating on conveyor lines. Another application is the characterization of a material constituting a body or present in a body, in this case solid, liquid, pasty or viscous bodies; with an example of application in tests on a liquid (such as water) aimed at evaluating the concentration or presence of a component (such as a pollutant, such as a micro-plastic, a hydrocarbon, others) in the liquid. Prior art

[0004] In a manner known within the non-limiting scope of the preferred application cited above, a waste collection or sorting installation, such as a selective sorting container, is intended to receive waste of the same nature, that is to say waste made from the same materials, or at least from materials belonging to the same recycling sector, such as for example plastic materials, cardboard or paper materials, metal materials or glass materials. Thus, it is the user who carries out the sorting by selecting the container adapted to the waste that he wishes to see recycled.

[0005] However, it happens that waste is deposited in unsuitable selective sorting containers, for example plastic waste in a container for glass or metal waste in a container for plastics. There is therefore a need for a reliable solution to characterize the material of the waste in order to be able to determine whether the container is polluted by unsuitable waste, and thus to be able to inform the recycling operator of the presence and quantity of unsuitable waste.

[0006] Such a solution would also be of interest for informing users who deposit their waste in unsuitable selective sorting containers, in an educational approach to raising awareness, or even for rewarding users who deposit their waste in suitable selective sorting containers in an incentive approach to gratification. Summary of the invention

[0007] The invention therefore proposes a reliable characterization solution, suitable for characterizing the materials or matter of objects or bodies in motion, and in particular of waste which falls towards the inside of a selective sorting container.

[0008] Another aim is to have a repeatable characterization having sufficient sensitivity to distinguish at least plastic materials, metallic materials and glass materials, or even a characterization extended to all types of materials or materials, such as for example bio-waste materials, organic oils and vegetable oils.

[0009] To this end, the invention proposes a characterization system for characterizing a material or matter of an object or a moving body, this characterization system comprising a measuring chamber equipped with a radar wave transmitter / receiver device, this measuring chamber comprising a reflective wall capable of reflecting the radar waves and a support wall on which the radar wave transmitter / receiver device is mounted, in which: - the reflective wall has a general shape of a concave trough extending along a longitudinal axis, having a given length measured along this longitudinal axis and forming a guide for the moving object or body; - the reflective wall has a main cross-section, in a main transverse plane which is orthogonal to the longitudinal axis and which passes through the radar wave transmitter / receiver device, which is inscribed in an ellipse having a first focus and a second focus, and an ellipse axis passing through the first focus and the second focus; and - the first focus is positioned on the radar wave transmitter / receiver device inside the reflective wall and the second focus is positioned inside the reflective wall.

[0010] Thus, the invention proposes to use characterization by radar waves, preferably in frequencies between 30 GHz and 100 GHz, by exploiting an elliptical shape such that the radar waves, emitted by the radar wave transmitter / receiver device at the first focus, are directed or focused at the second focus where the moving object (or body) is advantageously located, due to the elliptical shape. In this way, the emitted radar waves are concentrated on the second focus, and therefore on the moving object (or body), which makes it possible to maximize the passage of radar waves through the moving object (or body) whose material or matter is to be characterized. This elliptical shape also makes it possible to concentrate the reflected radar waves on the first focus, where the transmitter / receiver device is located, and therefore to increase the power of the received signals which will be used to characterize the material or matter.

[0011] According to one characteristic, the reflective wall has, over its entire length and continuously, cross sections, including the main cross section, in transverse planes which are orthogonal to the longitudinal axis, and in which the cross sections are all inscribed in ellipses.

[0012] Thus, this elliptical shape is continuous over the entire length of the reflective wall, for optimization of the concentration of the radar waves on the second focus, and of the concentration of the reflected radar waves on the first focus. Indeed, the surface of the object (or body) in motion, the surface of the emission of the radar waves and the surface of the reception (or detection) of the reflected radar waves are not point surfaces, and it is therefore advantageous to extend this elliptical shape in length to maximize the powers in emission and in reflection, in other words to increase the exploitation of the angle of emission of the radar waves thanks to the length of the reflective strip.

[0013] In a first embodiment, the ellipses are all geometrically identical so that the reflective wall is inscribed in an elliptical cylinder.

[0014] In other words, the reflecting wall has a truncated elliptical cylinder shape. Thus, the reflecting wall has a simple elliptical curvature. This elliptical cylinder shape is advantageous with a radar wave emission surface and a surface for receiving (or detecting) the reflected radar waves which are extended longitudinally.

[0015] In a second embodiment, the ellipses evolve geometrically and continuously along the longitudinal axis so that the reflective wall is inscribed in an ellipsoid.

[0016] In other words, the reflecting wall has a truncated ellipsoid shape. Thus, the reflecting wall has a double elliptical curvature. This ellipsoid shape is advantageous for increasing the concentrations of radar waves emitted on the second focus (or on a restricted area around the second focus) and increasing the concentrations of radar waves reflected on the first focus (or on a restricted area around the first focus).

[0017] Advantageously, the ellipse axis is an axis of symmetry of the ellipsoid.

[0018] Thus, the first focus and the second focus define an axis of symmetry of the ellipsoid, and therefore the radar wave transmitter / receiver device is positioned to receive a maximum of reflected radar waves.

[0019] According to one possibility, the principal transverse plane is a first plane of symmetry of the ellipsoid.

[0020] In other words, the first focus and the second focus are in this first plane of symmetry of the ellipsoid, to increase the concentrations on these two focuses.

[0021] Alternatively, the ellipsoid has a second plane of symmetry that includes the longitudinal axis and passes through the first focus and the second focus.

[0022] According to another possibility, the reflective wall has a longitudinal section in the second plane of symmetry which is inscribed in an ellipse having as foci the first focus and the second focus.

[0023] In this case, the concentrations of the radar waves on the first focus and on the second focus are optimized, because the ellipse in the first plane of symmetry and the ellipse in the second plane of symmetry have their foci merged.

[0024] In a particular embodiment, the longitudinal axis is non-horizontal.

[0025] Thus, the reflective wall offers a slope and thus makes it possible to guide the moving object (or body) which slides in the reflective wall downwards due to this slope, preferably towards a container.

[0026] Advantageously, the second focus is positioned at a given distance from the reflecting wall measured along the ellipse axis, where this distance is between 1 and 50 centimeters, and for example between 2 and 20 centimeters.

[0027] For the moving object (or body) to pass through this second focus and therefore for the radar waves to pass multiple times through this object, this object must be high enough to pass through this second focus, that is to say it must have at least one dimension greater than this distance. This distance is therefore adapted according to the objects or bodies that one wishes to characterize with the characterization system. Having a distance between 1 and 50 centimeters allows multiple applications, particularly in the waste sector. However, it is possible to have greater distances if one considers larger objects, such as for example large industrial parts.

[0028] In a particular embodiment, the reflective wall has an external layer transparent to radar waves and having a coefficient of friction less than 0.2.

[0029] Such an external layer thus makes it possible to provide a sliding surface for the moving object or body, thus allowing the latter to pass through the measuring chamber without difficulty and without risk of blockage.

[0030] According to one possibility, the outer layer is made of polytetrafluoroethylene or polyoxymethylene.

[0031] In a particular embodiment, the length of the reflective wall, measured along the longitudinal axis, is between 0.1 and 10 centimeters.

[0032] Such a length is in fact sufficient to obtain good characterization results, with regard to the multiple reflections which can take place on the reflective wall.

[0033] According to one possibility, the reflective wall has a height, called reflective height, given measured along the ellipse axis, the first focus is positioned at a given distance, called first distance, from the reflective wall measured along the ellipse axis.

[0034] In a first embodiment, the ratio of the reflective height to the first distance is between 0.5 and 1.0.

[0035] Thus, the radar wave transmitter / receiver device is located above the reflective wall and therefore outside the measuring chamber, and the reflective height is at least greater than half of the first distance, which means that the reflective wall rises high, thus increasing the reflective surface offered by this reflective wall, and therefore increasing the reflections of the radar waves on it, thus contributing to improving the sensitivity of the characterization.

[0036] Alternatively, the ratio of the reflective height to the first distance is between 0.80 and 0.95.

[0037] In a second embodiment, the ratio of the reflective height to the first distance is greater than or equal to 1.0; and thus the radar wave transmitter / receiver device is located inside the measuring chamber.

[0038] In other words, the reflective wall goes back almost to the first focus, for a larger reflective surface.

[0039] Advantageously, the reflective wall has two upper edges extending opposite each other, and the support wall is fixedly mounted on these upper edges of the support wall, so that the reflective wall and the support wall together delimit the measuring chamber.

[0040] Thus the measuring chamber has a closed tubular section to concentrate the radar waves inside this measuring chamber.

[0041] In a particular embodiment, the support wall has a lower face facing the reflective wall, and an upper face opposite the lower face, and in which the radar wave transmitter / receiver device is arranged on the side of the upper face of the support wall, opposite an opening made in the support wall for the passage of the radar waves.

[0042] Thus, the radar wave transmitter / receiver device is outside the measuring chamber and it sends / receives the radar waves which pass through the opening.

[0043] According to one possibility, the opening of the support wall is covered by a panel made of a material transparent to radar waves.

[0044] Thus, the radar wave transmitter / receiver device is protected in a sealed manner from anything passing into the measuring chamber, thus avoiding damage to this device.

[0045] Alternatively, the lower face of the support wall is a reflective face capable of reflecting radar waves, or the lower face of the support wall is covered with a reflective upper wall capable of reflecting radar waves.

[0046] In this way, the radar waves can also be reflected at the level of this lower face of the support wall, thus helping to obtain multiple reflections which will improve the characterization.

[0047] According to another possibility, the characterization system comprises a housing inside which the radar wave transmitter / receiver device is arranged, where the support wall is a bottom wall of this housing.

[0048] This housing protects the electronics contained in the radar wave transmitter / receiver device.

[0049] According to one characteristic, the characterization system comprises an upstream conduit extending the reflective wall and forming a guide path for guiding the object or body in motion towards the measuring chamber.

[0050] Thus, the object (or body) slides into the upstream conduit to enter the measuring chamber.

[0051] The invention also relates to an installation for collecting or sorting objects comprising a container provided with a mouth on which is mounted a characterization system as described previously.

[0052] This mouth delimits an orifice opening into the measuring chamber. Thus, in situation, the object (or the body) is introduced into the orifice and is guided into the measuring chamber to be characterized there. This mouth can optionally be equipped with a trapdoor or a valve allowing the orifice to be closed. Brief description of the drawings

[0053] Other characteristics and advantages of the present invention will appear on reading the detailed description below, of a non-limiting example of implementation, made with reference to the appended figures in which:

[0054] [Fig-1] is a schematic perspective view of a collection or sorting installation of objects equipped with a characterization system (not visible in this [Fig.l]) mounted on a cover;

[0055] [Fig.2] is a partial schematic and perspective view of the installation of the [Fig.l] without the cover, in order to visualize the characterization system which is coupled to a hood;

[0056] [Fig.3] is another schematic perspective view of the characterization system of [Fig.2], with the hood;

[0057] [Fig.4] is a schematic perspective and exploded view of the system of characterization of [Fig.2], with the hood;

[0058] [Fig.5] is a schematic perspective and exploded view of the system of characterization of [Fig.2], without the hood;

[0059] [Fig.6] is a schematic sectional view of the characterization system of [Fig.2], in a section plane corresponding to the main transverse plane in which the first focus and the second focus are positioned;

[0060] [Fig.7] is a schematic sectional view of the characterization system of [Fig.2], in the same sectional plane as in [Fig.6], and in which only the radar wave transmitter / receiver device and the reflecting wall are illustrated;

[0061] [Fig.8] is a schematic perspective view of the characterization system of the [Fig.2], where the radar wave transmitter / receiver device is clearly visible because the housing, the support wall and the reflective upper wall are not illustrated;

[0062] [Fig.9] is a partial schematic view, in perspective and in axial section of the characterization system of [Fig.2], according to a longitudinal section plane including the longitudinal axis and the ellipse axis;

[0063] [Fig. 10] is a schematic perspective and axial sectional view of the characterization system of [Fig.2], with the hood, along the same longitudinal sectional plane as in [Fig.9].

[0064] [Detailed description of an embodiment of the invention]

[0065] The following description concerns a characterization system 1 installed within an object collection or sorting installation 2 such as for example illustrated in [Fig.l]. Thus, this characterization system 1 is used for characterizing a material or matter of an object or body in motion and previously introduced into the object collection or sorting installation 2; it may be, as illustrative and non-limiting examples, a characterization of plastic materials, metallic materials and glass materials, or even bio-waste materials, organic oils and vegetable oils.

[0066] This object collection or sorting installation 2 comprises a container 20 provided with a mouth 21 on which the characterization system 1 is mounted, with reference to [Fig. 2]. The mouth 21 delimits an orifice 22 provided for introducing an object (generally waste), and this mouth 21 is provided with a trapdoor 23 (or valve).

[0067] This characterization system 1 comprises a chassis 10 which comprises two successive parts which are an upstream conduit 11 and a measuring chamber 12. The upstream conduit 11 is fixed on the mouth 21 in the extension of its orifice 22, so that the object introduced into the orifice 22 of the mouth 21 enters the upstream conduit 11. This upstream conduit 11 forms a closed tunnel which defines a guide path which is inclined relative to the horizontal so that the object can slide by gravity in this upstream conduit 11 until it reaches the measuring chamber 12.

[0068] The measuring chamber 12 comprises a reflective wall 3 capable of reflecting radar waves, where this reflective wall 3 has a general shape of a concave “U” trough. Thus, the reflective wall 3 has two upper edges 31 extending opposite each other. The reflective wall 3 is part of the chassis 10 and it may be envisaged to use a reflective coating 32 to provide this capacity to reflect radar waves.

[0069] The measuring chamber 12 also comprises a support wall 4 which is fixed to the frame 10, above the reflective wall 3, in order to close the measuring chamber 12 in the manner of a cover. More precisely, the support wall 4 is fixedly mounted on the upper edges 31 of the support wall 3, so that the reflective wall 3 and the support wall 4 together delimit the measuring chamber 12. Thus, this support wall 4 is not part of the frame 10 and it is fixedly attached to this frame 10, for example by screwing, welding, or other fixing means.

[0070] The measuring chamber 12 is equipped with a radar wave transmitter / receiver device 5, which is in the form of a system on a chip (or in English "System on a chip", abbreviated to SoC) having at its center the transmitter / receiver 50 and at its periphery an antenna on a chip 51 (or in English "antenna on a chip"). This radar wave transmitter / receiver device 5 is mounted on the support wall 4 which has an opening 40 (or window) for the passage of the emitted and reflected radar waves.

[0071] Thus, the radar wave transmitter / receiver device 5 is arranged above and opposite the reflective wall 3 for: - emit radar waves inside the measuring chamber 12, these radar waves passing through the object and being reflected by the reflective wall 3; and - receive the reflected radar waves for analysis used to characterize the material of the object (or the material of the body).

[0072] More precisely, the support wall 4 has a lower face 41 facing the reflective wall 3, and an upper face 42 opposite the lower face 41, and the radar wave transmitter / receiver device 5 is arranged on the side of the upper face 42 of the support wall 4, opposite the opening 40 provided in the support wall 4 for the passage of the radar waves. The radar wave transmitter / receiver device 5 is in particular housed inside a housing 6 closed by a cover 60, where the wall support 4 is a bottom wall of this housing 6; that is to say that the support wall 4 is part of the housing 6, and this housing 6 is fixed on the chassis 10.

[0073] This opening 40 of the support wall 4 is covered by a panel 43 made of a material transparent to radar waves, thus making it possible to seal this opening 40 in a watertight manner while allowing the radar waves to pass through. This panel 43 is for example made of polytetrafluoroethylene or polyoxymethylene.

[0074] The lower face 41 of the support wall 4 is covered with a reflective upper wall 44 (such as for example a film or a coating) capable of reflecting the radar waves, in order to have a reflective face capable of reflecting the radar waves. In this case, this reflective upper wall 44 is also provided with an opening 45, which coincides with the opening 40 provided in the support wall 4 and which is also covered by the panel 43 transparent to the radar waves. Alternatively, the lower face 41 of the support wall 4 is a reflective face capable of reflecting the radar waves.

[0075] The remainder of the description relates to the reflective wall 3, and in particular to its geometric shape. This reflective wall 3 therefore has a general shape of a concave “U” shaped chute which extends along a longitudinal axis 30; this longitudinal axis 30 being advantageously inclined relative to the horizontal to have a slope promoting sliding and falling of the object.

[0076] This reflective wall 3 has a given length L3 measured along this longitudinal axis 30 and it forms a guide for the moving object or body. In the illustrated example, the reflective wall 3 comprises a reflective coating 32, and the length L3 corresponds to the length of this reflective coating 32. This length L3 can be between 0.1 and 10 centimeters.

[0077] With reference to [Fig.7], the reflective wall 3 (or the reflective coating 32) has a main cross-section, in a main transverse plane which is orthogonal to the longitudinal axis 30 and which passes through the radar wave transmitter / receiver device 5 (and in particular through the transmitter / receiver 50), which is inscribed in an ellipse 8 having a first focus 81 and a second focus 82, and an ellipse axis 80 passing through the first focus 81 and the second focus 82.

[0078] The first focus 81 is positioned on the radar wave transmitter / receiver device 5, and more precisely on the transmitter / receiver 50, and the second focus 82 is positioned inside the reflective wall 3.

[0079] With reference to [Fig.7], the reflective wall 3 has a height, called the reflective height H3, given measured along the ellipse axis 80 up to the upper edges 31, the first focus 81 is positioned at a given distance, called the first distance D1, from the reflective wall 3 measured along the ellipse axis 80, and the second focus 82 is positioned at a given distance, called the second distance D2, from the reflective wall 3 measured along the ellipse axis 80, and the ellipse 8 has a given ellipse height H8 measured along the ellipse axis 80.

[0080] The reflective height H3 is comparable to the height of the measuring chamber 12 and it is less than the ellipse height H8.

[0081] In the example illustrated, the first focus 81 is located above the upper edges 31 of the reflective wall 3, in the sense that the first distance DI is greater than the reflective height H3. In this case, the radar wave transmitter / receiver device 5 is in some way located outside the measuring chamber 12, above the latter. In this example, the ratio of the reflective height H3 to the first distance D1, i.e. H3 / D1, is less than 1 and can be between 0.5 and 1.0, and for example this ratio H3 / D1 is between 0.80 and 0.95. Thus, the reflective height H3 is almost equivalent to the first distance D1, which contributes to increasing the reflective surface and therefore the sensitivity of the detection.

[0082] In a variant not illustrated, the first focus 81 is located below the upper edges 31 of the reflective wall 3, in the sense that the first distance D1 is less than or equal to the reflective height H3. In this case, the radar wave transmitter / receiver device 5 is in some way located inside the measuring chamber 12. In this example, the ratio of the reflective height H3 to the first distance D1, i.e. H3 / D1, is greater than or equal to 1.

[0083] The second distance D2 is between 1 and 50 centimeters, and for example between 2 and 20 centimeters, in the application to the installation for collecting or sorting objects 2.

[0084] The reflective wall 3 (or the reflective coating 32) has, over its entire length L3 and continuously, cross-sections, including the main cross-section, in transverse planes which are orthogonal to the longitudinal axis 30, and in which the cross-sections are all inscribed in ellipses.

[0085] Thus, two variants are possible: - first variant: the ellipses are all geometrically identical so that the reflective wall 3 (or the reflective coating 32) is inscribed in an elliptical cylinder, in other words the reflective wall 3 has the general shape of an elliptical cylinder sectioned according to a cut which passes through the upper edges 31; - second variant: the ellipses evolve geometrically and continuously along the longitudinal axis 30 so that the reflective wall 3 (or the reflective coating 32) is inscribed in an ellipsoid, in other words the reflective wall 3 has a general shape of an ellipsoid having the first focus 81 and the second focus 82, and sectioned according to a cut which passes through the upper edges 31, the ellipse axis 80 being an axis of symmetry of the ellipsoid.

[0086] In the first variant, the reflective wall 3 has a simple elliptical curvature around the longitudinal axis 30.

[0087] In the second variant, the reflecting wall 3 has a double elliptical curvature, namely a first elliptical curvature around the longitudinal axis 30 and a second elliptical curvature around a transverse axis 39 which is orthogonal to both the longitudinal axis 30 and the ellipse axis 80; this transverse axis 39 also forming an axis of symmetry of the ellipsoid.

[0088] As visible in Figures 7 and 8, in the main transverse plane, the radar waves 55 emitted by the radar wave transmitter / receiver device 5 (and in particular by the transmitter / receiver 50) on the first focus 81, are focused on the second focus 82, and therefore pass through the object 9 or the body (shown schematically by a circle); and the reflected waves return to the radar wave transmitter / receiver device 5 (and in particular to the transmitter / receiver 50) on the second focus 82.

[0089] This principle extends to the two variants described above, both based on an elliptical geometry, in order to confine the radar waves and focus them at two precise points (the first focus 81 in transmission, and the second focus 82 in reception), so as to maximize the passages of the waves through the materials to be analyzed, and therefore maximize the power of the signals received; in other words these elliptical cylinder and ellipsoid shapes make it possible to optimize the power of the signal received after multiple reflections in the measuring chamber 12 and consequently multiple passages through the object 9 (or the body) to be characterized.

Claims

Claims

1. Characterization system (1) for characterizing a material or matter of an object or a moving body, said characterization system (1) comprising a measuring chamber (12) equipped with a radar wave transmitter / receiver device (5), said measuring chamber (12) comprising a reflective wall (3) capable of reflecting the radar waves and a support wall (4) on which the radar wave transmitter / receiver device (5) is mounted, wherein: - the reflective wall (3) has a general shape of a concave trough extending along a longitudinal axis (30), having a given length (L3) measured along this longitudinal axis (30) and forming a guide for the object or the moving body;- the reflective wall (3) has a main cross-section, in a main transverse plane which is orthogonal to the longitudinal axis (30) and which passes through the radar wave transmitter / receiver device (5), which is inscribed in an ellipse (8) having a first focus (81) and a second focus (82), and an ellipse axis (80) passing through the first focus (81) and the second focus (82); and - the first focus (81) is positioned on the radar wave transmitter / receiver device (5) and the second focus (82) is positioned inside the reflective wall (3).;

2. Characterization system (1) according to claim 1, in which the reflective wall (3) has over its entire length (L3) and continuously cross sections, including the main cross section, in transverse planes which are orthogonal to the longitudinal axis (30), and in which the cross sections are all inscribed in ellipses.

3. Characterization system (1) according to claim 2, in which the ellipses are all geometrically identical so that the reflective wall (3) is inscribed in an elliptical cylinder.

4. Characterization system (1) according to claim 2, in which the ellipses evolve geometrically and continuously along the longitudinal axis (30) so that the reflective wall (3) is inscribed in an ellipsoid.

5. Characterization system (1) according to claim 4, wherein the ellipse axis (80) is an axis of symmetry of the ellipsoid.

6. Characterization system (1) according to any one of the preceding claims, wherein the longitudinal axis (30) is non-horizontal.

7. Characterization system (1) according to any one of the preceding claims, in which the second focus (82) is positioned at a given distance, called second distance (D2), from the reflective wall (3) measured along the ellipse axis (80), where this second distance (D2) is between 1 and 50 centimeters, and for example between 2 and 20 centimeters.

8. Characterization system (1) according to any one of the preceding claims, wherein the reflective wall (3) has an external layer transparent to radar waves and having a coefficient of friction less than 0.

2.

9. Characterization system (1) according to claim 8, wherein the outer layer is polytetrafluoroethylene or polyoxymethylene.

10. Characterization system (1) according to any one of the preceding claims, wherein the length (L3) of the reflective wall (3), measured along the longitudinal axis (30), is between 0.1 and 10 centimeters.

11. Characterization system (1) according to any one of the preceding claims, in which the reflective wall (3) has a height, called reflective height (H3), given measured along the ellipse axis (80), the first focus (81) is positioned at a given distance, called first distance (Dl), from the reflective wall (3) measured along the ellipse axis (80).

12. Characterization system (1) according to claim 11, wherein the ratio of the reflective height (H3) to the first distance (Dl) is between 0.5 and 1.0, and for example between 0.80 and 0.

95.

13. Characterization system (1) according to claim 11, wherein the ratio of the reflective height (H3) to the first distance (Dl) is greater than or equal to 1.

0.

14. Characterization system (1) according to any one of the preceding claims, wherein the reflective wall (3) has two upper edges (31) extending opposite each other, and the support wall (4) is fixedly mounted on these upper edges (31) of the support wall (4), so that the reflective wall (3) and the support wall (4) together delimit the measuring chamber (12).

15. Characterization system (1) according to any one of the preceding claims, wherein the support wall (4) has a lower face (41) facing the reflective wall (3), and an upper face (42) opposite the lower face (41), and wherein the radar wave transmitter / receiver device (5) is arranged on the side of the upper face (42) of the support wall (4), opposite an opening (40) provided in the support wall (4) for the passage of radar waves.

16. Characterization system (1) according to claim 15, wherein the opening (40) of the support wall (4) is covered by a panel (43) made of a material transparent to radar waves.

17. Characterization system (1) according to claim 15 or 16, wherein the lower face (41) of the support wall (4) is a reflective face capable of reflecting radar waves, or the lower face (41) of the support wall (4) is covered with a reflective upper wall (44) capable of reflecting radar waves.

18. Characterization system (1) according to any one of the preceding claims, comprising a housing (6) inside which the radar wave transmitter / receiver device (5) is arranged, where the support wall (4) is a bottom wall of this housing (6).

19. Characterization system (1) according to any one of the preceding claims, comprising an upstream conduit (11) extending the reflective wall (3) and forming a guide path for guiding the moving object or body towards the measuring chamber (12).

20. Installation for collecting or sorting objects (2) comprising a container (20) provided with a mouth (21) on which is mounted a characterization system (1) according to any one of the preceding claims.

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