MEASUREMENT EQUIPMENT FOR SPECTROSCOPIC ANALYSIS OF INDIVIDUAL MOVING OBJECTS

Abstract

Measurement equipment can be used for control with spectroscopic analysis of individual moving objects. The measurement equipment includes a probe with a surface, from which one or more illumination optical fibres and measurement optical fibres emerge. The optical fibres are arranged so that at least one of the second acceptance cones intersects at least one first acceptance cone at less than 10 mm from the surface. The measurement equipment includes a triggering device detecting the objects upstream of the probe to activate or deactivate the observation of the objects by the probe.

Claims

1. A measurement equipment comprising a probe for observing objects moving along a longitudinal direction, for carrying out a spatially resolved spectroscopic analysis on said objects, a triggering device offset from the probe along the longitudinal direction, and a control unit; the probe comprising: a surface extending along the longitudinal direction and along a lateral direction perpendicular to the longitudinal direction, one or more first optical fibres opening out onto said surface and arranged to emit electromagnetic radiation from at least one source, each first optical fibre having a first acceptance cone, second optical fibres opening out onto said surface, and arranged to capture electromagnetic radiation and transmit the electromagnetic radiation to a receiving device, each second optical fibre having a second acceptance cone, the second optical fibres being offset from the first optical fibre or fibres along the longitudinal direction and located on a same side of the first optical fibre or fibres; the probe being adapted so that at least one of the second acceptance cones intersects at least one first acceptance cone at less than 10 mm of said surface; the triggering device being configured to detect the objects; and the measurement equipment being configured to activate the observation of the objects by the probe in response to their detection by the triggering device.

2. The measurement equipment according to claim 1, wherein the triggering device comprises two detecting elements offset from each other along the lateral direction.

3. The measurement equipment according to claim 2, wherein the triggering device comprises separate laser detectors, the laser detectors being arranged to be displaceable along the lateral direction, each of the laser detectors comprising one of the detecting elements.

4. The measurement equipment of claim 2, wherein the triggering device emits a beam extending along the lateral direction, the detecting elements each comprising a separate segment of a detector arranged to capture the beam after reflection on the objects.

5. The measurement equipment according to claim 1, wherein the second optical fibres are distributed over the surface over a longitudinal extension and over a lateral extension such that the longitudinal extension is less than the lateral extension.

6. The measurement equipment according to claim 1, wherein the second optical fibres are distributed over a greater width than the first optical fibre or fibres, the width being taken along the lateral direction.

7. The measurement equipment according to claim 1, wherein the second optical fibres are distributed over a smaller length than the first optical fibre or fibres, the length being taken along the longitudinal direction.

8. The measurement equipment according to claim 1, wherein the first optical fibres are distributed in at most three laterally extending rows.

9. The measurement equipment according to claim 1, wherein the second optical fibres are distributed in at most three laterally extending rows.

10. A probe according to claim 1, wherein the second optical fibres are on average further apart from each other than the first optical fibres.

11. A measurement system comprising a measurement equipment according to claim 1, at least one source of electromagnetic radiation, a receiving device, and a conveyor arranged to transport the objects along the longitudinal direction so that the objects are detectable by the triggering device on a portion of the conveyor and are observable by the probe on a portion of the conveyor.

12. The measurement system according to claim 11, further comprising the objects, wherein the probe is above the objects, the measurement system being arranged so that a top of the objects is located between the surface and at least one intersection between a first acceptance cone and a second acceptance cone.

13. The measurement system according to claim 11, further comprising a spectral analysis device arranged to receive information from the receiving device.

14. A method of using the measurement equipment according to claim 1, comprising the first optical fibre or fibres emitting electromagnetic radiation towards the objects, and the second optical fibres receiving electromagnetic radiation from the objects.

15. The method according to claim 14, wherein detection of an object by the triggering device leads to an activation of the probe.

16. A method of using the measurement system according to claim 11, comprising the first optical fibre or fibres emitting electromagnetic radiation towards the objects, and the second optical fibres receiving electromagnetic radiation from the objects.

17. The method according to claim 16, wherein detection of an object by the triggering device leads to an activation of the probe.

Description

BRIEF DESCRIPTION OF THE FIGURES

[0056] Further characteristics and advantages of the invention will become apparent from the following detailed description, for the understanding of which reference is made to the appended figures, among which: [0057] FIG. 1 is a schematic lateral view of a measurement system according to one embodiment of the invention, [0058] FIG. 2a is a schematic lateral view of a probe according to one embodiment of the invention, [0059] FIG. 2b is a schematic lateral view of a probe according to another embodiment of the invention, [0060] FIG. 3 is a schematic top view of a probe and a conveyor according to one embodiment of the invention, [0061] FIG. 4 is a schematic bottom view of a probe having an optical fibre arrangement according to a first embodiment of the probe, [0062] FIG. 5a is a schematic bottom view of optical fibres in an arrangement according to a second embodiment of the probe, [0063] FIG. 5b is a schematic bottom view of optical fibres in an arrangement according to a third embodiment of the probe, [0064] FIG. 5c is a schematic bottom view of optical fibres in an arrangement according to a fourth embodiment of the probe, [0065] FIGS. 6a to 6f are successive schematic top views of the path of an object passing under the triggering device and then under the probe, [0066] FIG. 7a shows a first embodiment of the triggering device, and [0067] FIG. 7b shows a first embodiment of the triggering device.

EMBODIMENTS OF THE INVENTION

[0068] The present invention is described with particular embodiments and references to figures but the invention is not limited thereby. The drawings or FIGS. described are only schematic, are generally not to scale and are not limiting. In addition, the functions described may be carried out by structures other than those described in this document.

[0069] In the context of this present document, the terms “first” and “second” are used only to differentiate the various elements and do not imply an order between these elements.

[0070] In the figures, the identical or similar elements may have the same references.

[0071] FIG. 1 schematically illustrates a measurement system 9 according to one embodiment of the invention. The measurement system 9 comprises a measurement equipment 500 according to the invention, and a conveyor 3 arranged to transport the objects 2 along a moving direction 4. The measurement equipment 500 comprises a probe 1 and a triggering device 8 upstream of the probe 1, arranged so that the objects 2 are detectable by the triggering device on a portion of the conveyor 3 (the detection area of the triggering device 8) and observable by the probe 1 on a portion of the conveyor 3 (the observation area of the probe 1). The measurement system 9 further comprises at least one source 5 of electromagnetic radiation, a receiving device 6, and preferably a spectral analysis device 7 arranged to receive information from the receiving device 6. The objects 2 preferably have a horizontal extension between 2 and 25 mm. These are, for example, drugs.

[0072] The triggering device 8 preferably comprises a laser detector detecting the presence of objects 2 on the conveyor 3. It allows to activate the probe 1: the detection of an object 2 by the triggering device 8 results in an observation of the object 2 by the probe 1. In this way, only the objects 2 are observed by the probe 1, and the conveyor 3 is not considered.

[0073] The measurement equipment 500 preferably comprises a control unit 510 which exchanges information with, in particular, the triggering device 8 and the probe 1.

[0074] The probe 1 comprises a surface 100 oriented towards the conveyor 3, and on which one or more first optical fibres 10 and second optical fibres 20 open out. The ends of the first optical fibre or fibres 10 and the second optical fibres 20 are preferably flush with the surface 100. The surface 100 extends along a lateral direction 201 and a longitudinal direction 202 (shown in FIG. 3) which are perpendicular to each other. The probe 1 is preferably stationary. The trajectory of the objects 2 can be any. The moving linear speed is preferably between 0.1 and 3.0 m/s.

[0075] The source 5 emits electromagnetic radiation, in particular with an infrared component, which is transmitted by the first optical fibre or fibres 10 and emitted by the ends of the first optical fibre or fibres 10 towards the objects 2. The objects 2 reflect and scatter the electromagnetic radiation, in particular in the direction of the second optical fibres 20. When the electromagnetic radiation interacts with the objects 2, the characteristics of the electromagnetic radiation are changed. This will allow to carry out a spectroscopic analysis of the objects 2 based on the electromagnetic radiation scattered by the objects 2 and captured by the second optical fibres 20. The ends of the second optical fibres 20 thus capture electromagnetic radiation from the objects 2, and the second optical fibres 20 transmit this electromagnetic radiation to the receiving device 6.

[0076] The receiving device 6 preferably comprises a camera, with a CCD, which receives the electromagnetic radiation. The receiving device 6 sends information about the electromagnetic radiation to the spectral analysis device 7. The spectral analysis device 7 carries out a spectral analysis, preferably by infrared spectroscopy. The measurement system 9 can then compare the results of the spectral analysis with a theoretical model to determine physical and/or chemical characteristics of the objects 2. Calculation methods are put in place to take into account only the relevant information, and thus avoid the effects due to the edges of the objects 2.

[0077] As illustrated schematically in FIGS. 2a, 2b, each of the first optical fibres 10 has a first acceptance cone 11, and each of the second optical fibres 20 has a second acceptance cone 21. It is known to the person skilled in the art that the acceptance cone of an optical fibre is such that if a light ray attempts to penetrate the optical fibre from this cone, then the ray will be guided by total internal reflection; otherwise, the ray will not be guided.

[0078] The measurement system 9 is preferably arranged so that at least one intersection between first 11 and second 21 acceptance cones is between the top 2a of the objects 2 and the bottom of the objects 2.

[0079] In the invention, the arrangement of the first optical fibres 10 and the second optical fibres 20 on the surface 100 of the probe 1 is such that the second optical fibres 20 are offset from the first optical fibre or fibres 10 along the longitudinal direction 202 and located on a same side of the first optical fibre or fibres 10 and such that at least one of the second acceptance cones 21 intersects at least one of the first acceptance cones 11 (or the first acceptance cone 11 if there is only one first optical fibre) at less than 10 mm of the surface 100. Preferably, a first acceptance cone 11 and a second acceptance cone 21 intersect between 1 and 2 mm from the surface 100.

[0080] FIG. 3 shows schematically a possible arrangement of the probe 1 in relation to the conveyor 3. The conveyor 3 is preferably horizontal and carries the objects 2. The probe 1 is located above the conveyor 3, with the surface 100 oriented downwards. The objects 2 may be present in a single line on the conveyor 3 (as shown in FIG. 3), in several lines, or in a random arrangement.

[0081] In the scope of this document, the lateral direction 201 is the direction of the width of the conveyor 3, and the longitudinal direction 202 is the moving direction 4, and is perpendicular to the lateral direction 201. The lateral direction 201 could be referred to as “first direction”, and the longitudinal direction 202 could be referred to as “second direction” or “moving direction”.

[0082] In the invention, the arrangement of the first optical fibres 10 and the second optical fibres 20 on the surface 100 of the probe 1 is such that all the first optical fibres 10 of the probe 1 are inscribed in a first rectangle 13, and all the second optical fibres 20 of the probe 1 are inscribed in a second rectangle 23 which does not intersect the first rectangle 13. If the probe comprises only a first optical fibre 10, it is inscribed in a first rectangle 13 which does not intersect the second rectangle 23.

[0083] The first 13 and the second 23 rectangles preferably have two sides parallel to the direction of moving 4. The first 13 and second 23 rectangles are preferably inscribed in a 3 mm×4 mm rectangle.

[0084] The first rectangle 13 is preferably located upstream or downstream of the second rectangle 23 along the direction of moving 4. The first rectangle 13 and the second rectangle 23 are preferably centred laterally with respect to a same central longitudinal plane 50 (visible in FIG. 4) which is coincident with a longitudinal plane 31 centred with respect to the conveyor 3.

[0085] FIG. 4 illustrates an arrangement of the optical fibres in a first embodiment of the invention. Certain parameters of the invention are also shown, in particular the longitudinal extension 14 of the first optical fibres 10, the lateral extension 15 of the first optical fibres 10, the longitudinal extension 24 of the second optical fibres 20, and the lateral extension 25 of the second optical fibres 20 on the surface 100. When the probe 1 is taken in isolation from the conveyor 3, the lateral 201 and longitudinal 202 directions are perpendicular to each other, and are considered independently of any external referential.

[0086] The arrows 41 and 42 illustrate that the invention allows to obtain both a particularly short distance (arrow 41) and a particularly long distance (arrow 42) between a first optical fibre 10 and a second optical fibre 20.

[0087] FIG. 5a illustrates an arrangement of the optical fibres in a second embodiment of the invention. FIG. 5b illustrates an arrangement of optical fibres in a third embodiment of the invention. FIG. 5c illustrates an arrangement of optical fibres in a fourth embodiment of the invention.

[0088] The four illustrated embodiments, which are not limiting, allow to visualize certain characteristics of the invention, which can be considered in combination or independently within the scope of the invention: [0089] the longitudinal extension 24 of the second optical fibres 20 is preferably smaller than their lateral extension 25 (FIGS. 4, 5a, 5b, 5c); [0090] the longitudinal extension 14 of the first optical fibres 10 is preferably smaller than their lateral extension 15 (FIGS. 4, 5a, 5b, 5c); [0091] the lateral extension 25 of the second optical fibres 20 is greater than the lateral extension 15 of the first optical fibres 10 (FIGS. 4, 5a, 5b, 5c); [0092] the longitudinal extension 14 of the first optical fibres 10 is greater than (FIGS. 5a, 5b) or equal to (FIGS. 4, 5c) the longitudinal extension 24 of the second optical fibres 20; [0093] the first optical fibres 10 are distributed into two (FIG. 5b) or three (FIGS. 4, 5a, 5c) laterally extending rows; [0094] the second optical fibres 20 are distributed in one (FIG. 5a), two (FIG. 4, 5b) or three (FIG. 5c) laterally extending rows; [0095] the second optical fibres 20 are on average further apart from each other than the first optical fibres 10 (FIGS. 4, 5a, 5b, 5c); and/or [0096] there are more first optical fibres 10 than second optical fibres 20 (FIGS. 4, 5a, 5b, 5c).

[0097] FIGS. 6a to 6f illustrate the displacement of the object 2 with the conveyor 3. Considering a marker 91 on the triggering device 8 and a marker 92 on the probe 1, the distance 90 between these markers 91 and 92 is covered by the object 2 in a time t equal to the ratio between this distance 90 and the moving linear speed. The triggering device 8 comprises two detecting elements 81a, 81b laterally offset from each other. Each of the detecting elements 81a, 81b detects a point on the conveyor and the triggering device 8 sends information related to these points to the control unit 510. This information may be object detecting information (when the detecting element 81a or 81b detects the object 2) or conveyor detecting information (when the detecting element 81a or 81b does not detect the object 2 and therefore detects the conveyor 3).

[0098] In FIG. 6a, the object 2 is upstream of the triggering device 8. The triggering device 8 detects the conveyor 3, and optionally sends conveyor detecting information. The probe 1 is deactivated.

[0099] In FIG. 6b, the first detecting element 81a detects the object 2, whereas it previously detected the conveyor 3. The triggering device 8 sends the object detecting information for the first detecting element 81a to the control unit 510.

[0100] In FIG. 6c, the second detecting element 81b also detects the object 2, whereas it previously detected the conveyor 3. The triggering device 8 sends the object detecting information for the first detecting element 81a and for the second detecting element 81b to the control unit 510.

[0101] In FIG. 6d, the first 81a and the second 81b detecting elements detect the conveyor 3, whereas they previously detected the object 2. The triggering device 8 sends the conveyor detecting information for the first detecting element 81a and for the second detecting element 81b to the control unit 510. The control unit 510 optionally determines a model 85 of the object 2 and determines its time of arrival in the observation area of the probe 1. The front surface of the model 85 of the object 2 corresponds to the moment when the two detecting elements 81a, 81b detect the object 2 (between FIG. 6b and FIG. 6c). The rear surface of the model 85 of the object 2 corresponds to the moment when at least one of the two detecting elements 81a, 81b detect the conveyor 3 (between FIG. 6c and FIG. 6d).

[0102] The control unit 510 uses the information it has received from the triggering device 8, and the time t equal to the ratio between the distance 90 and the moving linear speed to determine a period of observation of the object 2 during which the probe 1 is activated to observe the object 2. Preferably, it uses the model 85 to determine the observation period of the object 2.

[0103] In FIG. 6e, the object 2 enters the observation area of the probe 1 to be observed by the probe 1. In FIG. 6f, the object 2 leaves the observation area of the probe 1 and is no longer observed by the probe 1. The period of observation of the object 2 preferably takes place when only the object 2 is observable by the probe 1 (between FIGS. 6e and 6f), for example when only the model 85 is observable by the probe 1. Thus, the probe 1 does not observe anything other than the object 2, thus allowing to avoid parasitic effects from observing a portion of the conveyor or edge effects.

[0104] FIG. 7a illustrates a first embodiment of the triggering device 8, in which it comprises laser detectors 82a, 82b each comprising one of the detecting elements 81a, 81b. They are arranged to be laterally displaceable. Preferably, each of the laser detectors 82a, 82b detects a point on the conveyor.

[0105] FIG. 7b illustrates a second embodiment of the triggering device 8, in which it comprises an emitter emitting a laterally extending beam 83 and a detector capturing the beam upon reflection on the object 2 or the conveyor 3. The detecting elements 81a, 81b each comprise a different segment of the detector, capable of detecting a different location on the object 2 or the conveyor 3. Each detecting element 81a, 81b is for example formed by one or more pixels, distinct from the pixel or the pixels of the other detecting element. The triggering device can be, for example, a 2D profilometer.

[0106] In other words, the invention relates to a measurement equipment 500 which can be used, in particular, in the context of a control with spectroscopic analysis of individual objects 2 which are in moving. The measurement equipment 500 comprises a probe 1 having a surface 100 into which one or more illumination optical fibres 10 and measurement optical fibres 20 open out. The optical fibres 10, 20 are arranged so that at least one of the second acceptance cones 21 intersects at least one first acceptance cone 11 at less than 10 mm of the surface 100. The measurement equipment 500 also comprises a triggering device 8 that detects the objects 2 upstream of the probe 1 so as to activate or deactivate the observation of the objects 2 by the probe.

[0107] The present invention has been described in relation to specific embodiments and arrangements, which are purely illustrative and are not to be regarded as limiting. In a general manner, the present invention is not limited to the examples illustrated and/or described above. The use of the verbs “comprise”, “include”, or any other variant, as well as their conjugations, can in no way exclude the presence of elements other than those mentioned. The use of the indefinite article “a”, “an”, or the definite article “the”, to introduce an element does not exclude the presence of a plurality of these elements. The reference numbers in the claims do not limit their scope.