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

Abstract

A characterization system (1) for characterizing a material or substance of an object or moving body, 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 concave channel shape and a principal cross-section that passes through the radar wave transmitter / receiver device and is inscribed in an ellipse having a first focus (81) and a second focus (82), and an axis of the ellipse (80) passing through the first and second focuses; 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 substance of an object or body in motion and associated object collection or sorting installation technical field

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

[0002] The invention finds a favorite, and not limiting, application in characterizing the materials of objects that are waste, in particular in a waste collection or sorting facility.

[0003] Other applications are conceivable, however, such as the characterization of materials in objects other than waste, like the contents of parcels, bags, or luggage for security purposes, or parts moving on conveyor lines. Another application is the characterization of a constituent material of or present in a body, in this case solid, liquid, paste, 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, like a microplastic, a hydrocarbon, etc.) in the liquid. Previous technique

[0004] As is known within the non-limiting scope of the preferred application cited above, a waste collection or sorting facility, such as a recycling container, is designed to receive waste of the same type, that is, waste made of the same materials, or at least of materials belonging to the same recycling stream, such as plastics, cardboard or paper, metal, or glass. Thus, the user sorts the waste by selecting the appropriate container for the type of waste they wish to have recycled.

[0005] However, waste is sometimes deposited in unsuitable recycling containers, for example, plastic waste in a glass container or metal waste in a plastics container. Therefore, there is a need for a reliable solution to characterize the material of the waste in order to determine if the container is contaminated by unsuitable waste, and thus 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 awareness-raising approach, or even for rewarding users who deposit their waste in suitable selective sorting containers in an incentive-based reward approach. Summary of the invention

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

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

[0009] To this end, the invention proposes a characterization system for characterizing a material or substance of an object or body in motion, this characterization system comprising a measurement chamber equipped with a radar wave transmitter / receiver device, this measurement chamber comprising a reflective wall capable of reflecting 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 gutter extending along a longitudinal axis, having a given length measured along this longitudinal axis and forming a guide for the object or body in motion; - the reflecting wall has a principal cross-section, in a principal transverse plane that is orthogonal to the longitudinal axis and passes through the radar wave transmitter / receiver device, which is inscribed in an ellipse having a first focus and a second focus, and an axis of the ellipse passing through the first and second focuses; and - the first focus is positioned on the radar wave transmitter / receiver device inside the reflecting wall and the second focus is positioned inside the reflecting wall.

[0010] Thus, the invention proposes to use radar wave characterization, 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), this maximizes the passage of radar waves through the moving object (or body) whose material or substance is to be characterized. This elliptical shape also concentrates the reflected radar waves on the first focus, where the transmitting / receiving device is located, thus increasing the power of the received signals used to characterize the material or substance.

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

[0012] Thus, this elliptical shape is continuous along the entire length of the reflecting wall, optimizing the concentration of radar waves at the second focus and the concentration of reflected radar waves at the first focus. Indeed, the surface of the moving object (or body), the surface of radar wave emission, and the surface of reflected radar wave reception (or detection) are not point surfaces, and it is therefore advantageous to extend this elliptical shape in length to maximize the transmission and reflection powers, in other words, to increase the exploitation of the radar wave emission angle thanks to the length of the reflecting 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 the shape of a truncated elliptical cylinder. Thus, the reflecting wall has a simple elliptical curvature. This elliptical cylinder shape is advantageous with a radar wave emission surface and a reflected radar wave reception (or detection) surface that are longitudinally extended.

[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 ellipsoidal shape. Thus, the reflecting wall has a double elliptical curvature. This ellipsoidal shape is advantageous for increasing the concentrations of radar waves emitted at the second focus (or on a restricted area around the second focus) and increasing the concentrations of radar waves reflected at the first focus (or on a restricted area around the first focus).

[0017] Advantageously, the axis of the ellipse 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, in order to increase the concentrations on these two focuses.

[0021] According to another possibility, the ellipsoid has a second plane of symmetry which includes the longitudinal axis and which 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 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 coincide.

[0024] In a particular embodiment, the longitudinal axis is not horizontal.

[0025] Thus, the reflective wall offers a slope and thus allows the moving object (or body) to be guided downwards in the reflective wall 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 axis of the ellipse, 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 for the radar waves to pass through it multiple times, the object must be sufficiently tall to pass through this second focus; that is, 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. A distance between 1 and 50 centimeters allows for numerous applications, particularly in the waste management sector. However, it is possible to have greater distances if one considers larger objects, such as large industrial parts.

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

[0029] Such an outer layer thus makes it possible to offer a sliding surface for the object or body in motion, thus allowing the latter to pass through the measuring chamber without difficulty and without risk of blocking.

[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 indeed sufficient to obtain good characterization results, with regard to the multiple reflections that can take place on the reflective wall.

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

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

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

[0036] According to another possibility, 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 reflector 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 up almost to the first focus, for a larger reflective surface.

[0039] Advantageously, the reflecting 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 reflecting 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 reflecting wall, and an upper face opposite the lower face, and in which the radar wave transmitter / receiver device is disposed on the side of the upper face of the support wall, opposite an opening provided in the support wall for the passage of radar waves.

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

[0043] According to one possibility, the opening in 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 hermetically protected from anything that passes into the measurement chamber, thereby preventing damage to this device.

[0045] According to another possibility, 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, radar waves can also be reflected at the level of this lower face of the support wall, thus contributing to obtaining 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 disposed, 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 feature, the characterization system includes an upstream conduit extending the reflective wall and forming a guide path to guide the moving object or body towards the measurement chamber.

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

[0051] The invention also relates to an object collection or sorting installation comprising a container equipped with an opening on which is mounted a characterization system as described above.

[0052] This opening defines an orifice leading into the measurement chamber. Thus, in operation, the object (or body) is introduced into the orifice and guided into the measurement chamber for characterization. This opening may optionally be equipped with a trapdoor or flap to close the orifice. Brief description of the drawings

[0053] Other features and advantages of the present invention will become apparent from the following detailed description of a non-limiting example of implementation, made with reference to the accompanying figures in which:

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

[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 the [Fig.2], with the hood;

[0057] [Fig.4] is a schematic perspective and exploded view of the system of characterization of the [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 cross-sectional view of the characterization system of [Fig.2], in a cutting plane corresponding to the main transverse plane in which the first focus and the second focus are positioned;

[0060] [Fig.7] is a schematic cross-sectional view of the characterization system of [Fig.2], in the same plane of section 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 casing, support wall and reflective top wall are not shown;

[0062] [Fig.9] is a partial schematic, perspective and axial section view of the characterization system of the [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 section view of the characterization system of [Fig.2], with the hood, along the same longitudinal section plane as in [Fig.9].

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

[0065] The following description relates to a characterization system 1 implemented within an object collection or sorting installation 2 such as, for example, illustrated in [Fig. 1]. Thus, this characterization system 1 is used for the characterization of a material or substance of an object or body in motion and previously introduced into the object collection or sorting installation 2; it may be, by way of illustrative and non-limiting examples, the 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 equipped with an opening 21 on which the characterization system 1 is mounted, with reference to [Fig.2]. The opening 21 defines an orifice 22 intended for the introduction of an object (generally waste), and this opening 21 is equipped with a trapdoor 23 (or flap).

[0067] This characterization system 1 comprises a frame 10 which includes two successive parts, an upstream conduit 11 and a measuring chamber 12. The upstream conduit 11 is fixed to the mouth 21 in line with 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 with respect 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 includes a reflective wall 3 adapted to reflect radar waves, wherein this reflective wall 3 has a general concave U-shaped channel. Thus, the reflective wall 3 has two upper edges 31 extending opposite each other. The reflective wall 3 forms part of the frame 10, and the use of a reflective coating 32 can be envisaged to impart this capacity to reflect radar waves.

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

[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 (SoC) having the transmitter / receiver 50 at its center and an antenna on a chip 51 at its periphery. 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 emitted and reflected radar waves.

[0071] Thus, the radar wave transmitter / receiver device 5 is arranged above and opposite the reflector wall 3 in order to: - to 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 reflected radar waves for analysis used to characterize the material of the object (or the material of the body).

[0072] More specifically, the support wall 4 has a lower face 41 facing the reflecting wall 3, and an upper face 42 opposite the lower face 41, and the radar wave transmitter / receiver device 5 is disposed 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 radar waves. The radar wave transmitter / receiver device 5 is in particular housed inside a casing 6 closed by a cover 60, where the wall support 4 is a bottom wall of this housing 6; that is to say, the support wall 4 is part of the housing 6, and this housing 6 is fixed to the chassis 10.

[0073] This opening 40 in 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 airtight while allowing the passage of radar waves. 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 surface 44 (such as a film or coating) capable of reflecting radar waves, so as to have a reflective surface capable of reflecting radar waves. In this case, this reflective upper surface 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 radar-transparent panel 43. Alternatively, the lower face 41 of the support wall 4 is a reflective surface capable of reflecting 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 channel which extends along a longitudinal axis 30; this longitudinal axis 30 being advantageously inclined with respect to the horizontal to have a slope which promotes the 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 axis of the ellipse 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 specifically on the transmitter / receiver 50, and the second focus 82 is positioned inside the reflective wall 3.

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

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

[0081] In the illustrated example, the first focal point 81 is located above the upper edges 31 of the reflecting wall 3, in the sense that the first distance DI is greater than the reflecting height H3. In this case, the radar wave transmitter / receiver device 5 is located, in a sense, outside the measuring chamber 12, above it. In this example, the ratio of the reflecting height H3 to the first distance Dl, 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 reflecting height H3 is almost equivalent to the first distance Dl, which helps to increase the reflective surface and therefore the sensitivity of the detection.

[0082] In an unillustrated embodiment, the first focus 81 is located below the upper edges 31 of the reflecting wall 3, in the sense that the first distance Dl is less than or equal to the reflecting height H3. In this case, the radar wave transmitter / receiver device 5 is located, in a sense, inside the measuring chamber 12. In this example, the ratio of the reflecting height H3 to the first distance Dl, 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 collection or sorting installation of objects 2.

[0084] The reflective wall 3 (or the reflective coating 32) has, along 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 a 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 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 axis of ellipse 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 reflective 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 can be seen in Figures 7 and 8, in the principal 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 (schematized 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 received signals; in other words, these elliptical cylinder and ellipsoid shapes allow the power of the received signal to be optimized after multiple reflections in the measurement chamber 12 and consequently multiple passages through the object 9 (or body) to be characterized.

Claims

Demands

1. Characterization system (1) for characterizing a material or substance of an object or body in motion, 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 radar waves and a support wall (4) on which the radar wave transmitter / receiver device (5) is mounted, in which: - the reflective wall (3) has a general shape of concave channel 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 body in motion;- the reflecting wall (3) has two upper edges (31) extending opposite each other, and the support wall (4) is fixedly mounted on these upper edges (31) so that the reflecting wall (3) and the support wall (4) together delimit the measuring chamber (12) which thus has a closed tubular section to concentrate the radar waves inside this measuring chamber (12); - the reflecting 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 axis of the ellipse (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 reflecting wall (3) and therefore inside the measuring chamber (12).

2. Characterization system (1) according to claim 1, wherein the reflective wall (3) has along 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 wherein the cross sections are all inscribed in ellipses.

3. Characterization system (1) according to claim 2, wherein 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, wherein 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, wherein the second focus (82) is positioned at a given distance, called second distance (D2), from the reflecting wall (3) measured along the axis of ellipse (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 outer 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 made of 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, wherein the reflecting wall (3) has a given height, called reflecting height (H3), measured along the axis of the ellipse (80) to the upper edges (31), the first focus (81) is positioned at a given distance, called first distance (Dl), from the reflecting wall (3) measured along the axis of the ellipse (80).

12. Characterization system (1) according to claim 11, wherein the ratio of the reflector 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 reflector 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 support wall (4) has a lower face (41) facing the reflecting wall (3), and an upper face (42) opposite the lower face (41), and wherein the radar wave transmitter / receiver device (5) is disposed 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.

15. Characterization system (1) according to claim 14, wherein the opening (40) of the support wall (4) is covered by a panel (43) made of a material transparent to radar waves.

16. Characterization system (1) according to claim 14 or 15, 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.

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

18. 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 to guide the moving object or body towards the measuring chamber (12).

19. Object collection or sorting installation (2) comprising a container (20) equipped with an opening (21) on which is mounted a characterization system (1) according to any one of the preceding claims.