Optical sorting of non-cereal fruits by combination of electromagnetic radiation

Abstract

The invention relates to a non-destructive method for determining the maturity and quality of a non-cereal fruit, a method for sorting non-cereal fruits, and a sorting apparatus for such non-cereal fruits implementing these methods. Figure from the abstract: Fig. 1

Description

Title of the invention: OPTICAL SORTING OF NON-CEREAL FRUITS BY COMBINATION OF ELECTROMAGNETIC RADIATION

[0001] The invention relates to a non-destructive method for determining the maturity and quality of a non-cereal fruit, a method for sorting non-cereal fruits and an apparatus for sorting such non-cereal fruits implementing these methods.

[0002] The industrialization of high-throughput sorting techniques for agri-food products from crops is essential for mass production, in particular for sorting products according to their maturity.

[0003] However, it is known that the maturity of products can be assessed by determining chromophoric compounds contained in plant cells. The targeted maturity may essentially concern phenolic maturity. This type of system offers the possibility of being used online and being inserted into a production line.

[0004] For example, methods for sorting rice grains by exposure to electromagnetic radiation and signal analysis are known from JPH11621A and KR20030088706.

[0005] Similarly, in EP0898701 a method for determining the maturity and quality of seeds by electromagnetic irradiation is reported.

[0006] Thus, these methods are particularly well suited to fruits / cereal products, typically having a limited number of maturity markers.

[0007] One of the advantages of these methods is furthermore the speed of the seed or rice grain selection step, which makes them particularly attractive for their application in high-throughput production lines. Furthermore, the fluorescence of chlorophyll is a determining factor in the methods thus described.

[0008] Concerning non-cereal fruits, it was reported by G. Agati et al. (“Nondestructive evaluation of anthocyanins in olive (Olea europaea) fruits by in situ chlorophyll fluorescence spectroscopy”; J Agric Food Chem. 2005, (5), 1354-63) that anthocyanins in olive (Olea europaea L.) fruits at different degrees of pigmentation were evaluated non-destructively by measuring chlorophyll fluorescence. This was achieved by a method based on the comparison of chlorophyll excitation spectra of different olives with different pigmentation, ranging from green to green-red, red-violet and violet. However, this technique is limited to so-called “low” or “medium” ripe fruits. Irradiation with green and red lights does not allow the full scale of ripeness to be assessed.

[0009] However, in WO 00 / 02036, the use of fluorescence is described to determine the presence or content of chlorophyll in a plant, particularly in berries. However, for the ripest berries, the level of chlorophyll can be very low. This weak chlorophyll fluorescence signal may even be insufficient to be detected, which can then cause sorting errors and a qualitative reduction in the sorted product. The technique is therefore perfectible. Furthermore, in WO 00 / 02036, the powers described are not sufficient, especially in the green: the technology described therefore seems limited to the screening of a so-called mature population.

[0010] The aim of the invention is therefore to overcome the drawbacks of the prior art and thus aims in particular to overcome the difficulties of sorting non-cereal fruits on an industrial scale.

[0011] Furthermore, generally, the fluorescence signal from chlorophyll is dependent on the excitation power and the chlorophyll level. Low chlorophyll levels require lighting powers that present a technical difficulty (i.e. a technological limit) and economic difficulty. Summary of the invention

[0012] To do this, a first aspect of the invention thus relates, in its broadest acceptance, to a non-destructive method for determining the maturity and quality of a non-cereal fruit comprising at least two stages of exposing said fruit to at least two different electromagnetic radiations and measuring their return signals, in which: - one of the steps of exposing said fruit comprises the provision of at least one wavelength capable of causing a chlorophyll fluorescence signal and a measurement, where appropriate, of said chlorophyll fluorescence signal; and - one of the steps of exposing said fruit to at least one electromagnetic radiation comprises the provision of at least one selected wavelength, capable of generating a reflection signal on said fruit, and a measurement, where appropriate, of said reflection signal.

[0013] Indeed, other maturity markers than chlorophyll are known (such as anthocyanins), which contribute to producing the characteristic colors of fruits. There is thus a mutual contribution of the different maturity markers which results in variations in the levels of these different markers in the fruits. The present invention uses this concept to assist the process of assessing the maturity of non-cereal fruits, and thus help to increase the accuracy of industrial sorting of such fruits.

[0014] One of the principles of the present invention is thus to be able to correlate a signal from an electromagnetic reflection chosen according to the sorted fruit with a signal chlorophyll fluorescence. The signals collected are thus complementary in that they provide different information useful for sorting. Thus, thanks to the method according to the present invention, selection becomes more precise and sorting of better quality.

[0015] The subject of the present invention also relates to a non-cereal fruit sorting apparatus comprising: - a non-cereal fruit feeding device, - optionally at least one means of removing objects that are not fruits; - at least one radiation system configured to generate at least one electromagnetic radiation; - at least one detection zone configured to measure and optionally analyze the return signals from said at least one radiation system; - a system for separating said fruits which can be activated according to the return signals, characterized in that: - said at least one radiation system is configured so as to expose said fruits to at least two different electromagnetic radiations; - one of said at least two electromagnetic radiations comprises at least one wavelength capable of causing chlorophyll fluorescence; - one of said at least two electromagnetic radiations comprises at least one wavelength chosen to generate a reflection on said fruit, such as 750 nm; - said at least one radiation system and the detection zone are arranged so as to: - that at least two return signals generated by said at least one radiation system are captured in the same detection zone, or - be on the same side of the fruits (otherwise, it would be possible for the fruit support to be transparent for example).

[0016] Thus, the apparatus according to the present invention allows an improvement in the sorting of non-cereal fruits thanks to a signal complementary to the signal obtained by the fluorescent excitation of chlorophyll. This complementary signal is calibrated specifically to the type of fruit that one wishes to sort. In addition, unlike apparatuses for sorting certain cereals such as rice, the radiation systems and the detection zones are placed on the same side of the fruit. Indeed, rice is partially translucent, which requires a different configuration of the detection and emission systems compared to other non-cereal fruits.

[0017] The present invention also makes it possible to identify objects which are not fruits: if no chlorophyll fluorescence signal is captured and the reflection signal is not characteristic of the fruit analyzed, it is therefore a foreign body. which can be removed. Other ways of distinguishing objects other than fruit can be used (e.g., weight-based measurement systems).

[0018] The subject of the present invention further relates to a method for sorting non-cereal fruits comprising the following steps: - individually bring each non-cereal fruit to at least one display area, - exposing said fruit in said at least one exposure zone to at least two different electromagnetic radiations, - receive and analyze the return signals from the exposure stage, - separate said fruits into different classes according to their individual signals, in which: - one of the at least two different electromagnetic radiations comprises at least one wavelength capable of causing chlorophyll fluorescence as a return signal; - one of the at least two different electromagnetic radiations comprises at least one wavelength chosen to generate a reflection on said fruit as a return signal; and - the values ​​that define the classes are pre-established or chosen based on a distribution of the reflection and fluorescence signals of chlorophyll emitted by a sample of non-cereal fruits with known properties.

[0019] Thus, this method makes it possible to use, if desired, a predefined threshold value, or to choose this threshold for sorting non-cereal fruits thanks to a preliminary study of a sample of the harvest that one wishes to sort. The present invention therefore makes it possible to maintain, if desired, a constant level, which one could qualify as "standardized", of the quality of the sorted fruits, or on the contrary to adapt the sorting to the reality of the harvest and thus to adjust for example the relationship between a sufficient production yield and the quality of the harvested fruits.

[0020] The invention (sorting methods and apparatus) is therefore particularly well suited for sorting fruits such as grapes in the context of the production of non-cereal fruit-derived products such as beverages such as wine, fruit juices, coulis, etc., dairy products comprising fruits or parts of fruits, such as fruit yogurts, or fruit desserts such as tarts, cakes, mousses, etc. which are particularly sensitive to the quality of the fruits used.

[0021] DEFINITIONS

[0022] By "non-cereal fruit" is understood within the scope of the present invention, a fruit which is not a cereal fruit. By "cereal" fruit is understood within the scope of the present invention, the botanical definition of a fruit, that is to say a grain, or even a seed, of a cereal. Cereals are monocotyledonous plants of the family of grasses, wild or cultivated, which produce edible grains, mainly used in human food, often ground into refined or more or less wholemeal flour. Examples of cereals are corn, wheat, rice, barley, sorghum, oats, rye, millet, triticale.

[0023] By "detection zone", it is understood within the scope of the present invention a surface sensitive to at least one electromagnetic radiation (i.e., light) and configured to transform a light signal into a usable signal, such as an electrical signal. Typically, such a detection zone is a camera, such as a digital camera like a CCD, CMOS camera. The camera can be matrix or linear. The detection zone can further be provided with one or more light filters to eliminate light signals of no interest in the scope of the present invention and thus improve the signal / background noise ratio.

[0024] By "return signal", it is understood in the context of the present invention the signal coming from the fruit to a sensor. This return signal can be a chlorophyll fluorescence signal or a reflection signal.

[0025] By "fluorescence signal", in the context of the present invention is understood the signal resulting from the excitation of chlorophyll.

[0026] By "reflection signal" is understood in the context of the present invention the light signal which is not absorbed by the non-cereal fruit and which is therefore reflected.

[0027] By "same side of a fruit" is understood in the context of the present invention a face of the fruit seen from a single external point of the fruit. DETAILED DESCRIPTION

[0028] • Method for determining the maturity and quality of a fruit:

[0029] The present invention relates in particular to a non-destructive method for determining the maturity and quality of a non-cereal fruit, such as grapes, comprising: - a first step of exposing said fruit to at least one electromagnetic radiation and measuring the return signal, - a second step of exposing said fruit to at least one electromagnetic radiation different from that of the first step and measuring the return signal, in which: - one of the steps of exposing said fruit comprises the provision of at least one wavelength capable of causing a chlorophyll fluorescence signal and a measurement, where appropriate, of said chlorophyll fluorescence signal; and - one of the steps of exposing said fruit to at least one electromagnetic radiation comprises the provision of at least one wavelength chosen capable of generating a reflection signal on said fruit, and a measurement, where appropriate, of said reflection signal.

[0030] Preferably, the method according to the present invention can be characterized in that the measurements of the chlorophyll fluorescence signal and of the reflection signal are carried out by the same sensor.

[0031] There are several advantages to using a single sensor for collecting the two return signals according to the invention. For example, a single sensor makes it possible to limit the financial cost of the equipment. A single sensor makes it possible to limit maintenance on the equipment. A single sensor allows for increased compactness of the equipment. A single sensor implies that the chlorophyll fluorescence and reflection signals come from the same face of the fruit analyzed, which makes it possible to better deduce an overall quality of the fruit thanks to a more precise correlation between the two signals.

[0032] Thus, advantageously, the method according to the present invention can be characterized in that the sensor is a camera optionally provided with a bandpass filter, for example a bandpass filter calibrated at 750 nm.

[0033] Thus, in a particular embodiment, the method according to the present invention can be characterized in that on the one hand, the supply of at least one wavelength capable of causing a chlorophyll fluorescence signal, and on the other hand the supply of at least one chosen wavelength capable of generating a reflection signal on said fruit, are sequenced (in time in a distinct manner) and / or synchronized, with optionally at least one pause time to allow the measurement of the background noise.

[0034] In a particular embodiment, the radiation systems comprise one or more light-emitting diode (LED)-based sources.

[0035] Preferably, the method according to the present invention can be characterized in that said at least one wavelength chosen to generate a reflection on said fruit is chosen with a wavelength significantly greater than the excitation wavelength of chlorophyll.

[0036] By "significantly greater than the chlorophyll excitation wavelength" is understood in the context of the present invention a wavelength which does not generate chlorophyll excitation capable of being detected (in particular in signal intensity) by the sensor employed.

[0037] More preferably, the method according to the present invention can be characterized in that the wavelength significantly greater than the excitation wavelength of chlorophyll is between 700 nm and 900 nm, preferably 750 nm plus or minus 10 nm.

[0038] For example, the method according to the present invention can be characterized in that the wavelength significantly greater than the excitation wavelength of the chlorophyll is between 710 nm and 850 nm, between 720 nm and 800 nm, between 730 nm and 780 nm or between 735 nm and 765 nm.

[0039] More preferably, the method according to the present invention can be characterized in that said at least one wavelength capable of causing fluorescence of the chlorophyll is between 550 nm and 680 nm, preferably 625 nm plus or minus 10 nm.

[0040] For example, the method according to the present invention can be characterized in that said at least one wavelength capable of causing fluorescence of chlorophyll is between 590 nm and 660 nm, between 600 nm and 650 nm or between 610 nm and 640 nm.

[0041] In a particular embodiment, the method according to the present invention can be characterized in that the wavelength significantly greater than the excitation wavelength of the chlorophyll is between 700 nm and 900 nm, preferably 750 nm plus or minus 10 nm, and in that said at least one wavelength capable of causing fluorescence of the chlorophyll is between 550 nm and 680 nm, preferably 625 nm plus or minus 10 nm.

[0042] The advantage is to be able to distinguish two different but complementary signals regarding the characteristics of a particular fruit.

[0043] For example, a fruit such as grapes comprises at least two maturity markers: chlorophyll and anthocyanins. Chlorophyll can be excited with an electromagnetic wave of wavelength between 550 and 680 nm, and the fluorescence thus generated can be between 720 and 770 nm, such as 750 nm plus or minus 10 nm.

[0044] Thus, one of the distinctive characteristics of the present invention is that chlorophyll is detected by fluorescence and the reflection signal makes it possible to have additional information (e.g. presence of an object and shape of the irradiated object).

[0045] To measure a fruit such as grapes, the fruit may undergo a first sequential red excitation (for example 625 nm) and an emission of a second light flux, for example 750 nm. The first return signal is therefore characteristic of the fluorescence of chlorophyll (for example approximately 750 nm) and the second return signal resulting from the reflection (for example approximately 750 nm) on the fruit of the second emission at 750 nm, characteristic of the presence of anthocyanins (second maturity marker).

[0046] In a particular and advantageous embodiment, the support which allows the fruit to be brought into the analysis zone (where it will be irradiated), does not interact or interacts little with the electromagnetic waves at the chosen wavelengths. Thus, the signals collected do not come from the support. For example, the support may include a transparent glazed part to avoid polluting the signal.

[0047] Thus, the irradiation powers (such as in the infrared) so that the support does not saturate the camera, are adapted specifically to the fruits analyzed. The return signal from the fruits is not drowned in a mass of signal which would come from the support.

[0048] Furthermore, in the context of the present invention, the residual chlorophyll content of a fruit such as grapes is measured while avoiding the masking effect of anthocyanins after excitation with an appropriate wavelength (e.g. 750 nm).

[0049] In this particular case in which the maturity markers are chlorophyll and anthocyanins, it may be particularly interesting to use a single detection zone (for example a single camera) given that the wavelengths of the return signals are close, or even identical (for example approximately 750 nm).

[0050] In the case of using a single detection zone, such as a camera, it is necessary to carry out sequential excitations, for example by using a band-pass filtered camera to enable the fluorescence to be measured on a wavelength in synchronization with each excitation, and to measure the return signal resulting from the reflection on a wavelength in synchronization with each excitation.

[0051] It may be advantageous depending on the method for the excitation and emission waves to be high-pass (frequency) filtered to remove wavelengths close to the fluorescence wavelength.

[0052] It may be advantageous depending on the method, for the system to continuously calibrate itself by including a measurement sequence without excitation to discriminate the background noise.

[0053] Thus, the method according to the present invention can be applied to any type of non-cereal fruit comprising chlorophyll and a second maturity marker whose return signal obtained by reflection or the return signal obtained by excitation differs from the excitation and fluorescence wavelengths of the chlorophyll. This therefore depends directly on the nature of the non-cereal fruit.

[0054] Preferably, the method according to the present invention can be characterized in that the non-cereal fruit comprises chlorophyll and at least one second maturity marker useful for reflection. Indeed, in the absence of chlorophyll the second marker will reflect the light (electromagnetic waves) to which the fruit is subjected.

[0055] Thus, preferably, the method according to the present invention can be characterized in that the non-cereal fruit contains at least one pigment (or maturity marker) chosen from lycopene, beta-carotene, anthocyanin and lutein, preferentially anthocyanin and / or lycopene.

[0056] Preferably, the method according to the present invention can be characterized in that the non-cereal fruit is a fleshy fruit.

[0057] A fleshy fruit is a fruit whose mesocarp has the consistency of a pulp, such as berries or drupes.

[0058] Preferably, the method according to the present invention can be characterized in that the non-cereal fruit is chosen from a tomato, a grape, a strawberry, a raspberry, a redcurrant, a cherry, a blackberry, a lingonberry, a blackcurrant, an aronia berry, a cranberry, a black elderberry and a blueberry, preferably a grape such as a red grape.

[0059] Preferably, the method according to the present invention can be characterized in that the non-cereal fruit is a red fruit.

[0060] In the context of the present invention, a red fruit is a berry such as a grape, a strawberry, a raspberry, a gooseberry, a cherry, a blackberry, a lingonberry, a blackcurrant, an aronia berry, a cranberry, a black elderberry or a blueberry, preferably a grape such as a red grape.

[0061] Furthermore, it may be advantageous to add to the method according to the present invention a complementary known technique of sorting based on the color of the non-cereal fruit.

[0062] • Method for sorting non-cereal fruits:

[0063] The object according to the present invention thus comprises a method for sorting non-cereal fruits applying the non-destructive method for determining the maturity and quality of a non-cereal fruit as described above to which the following steps will have been added: - individually bring each non-cereal fruit to at least one display area, - separate the said fruits into different classes according to their individual signals.

[0064] This method is put into practice by the sorting apparatus according to the invention generally described above and in more detail below.

[0065] • Apparatus for sorting non-cereal fruits:

[0066] The non-cereal fruit sorting apparatus according to the present invention comprises in particular a non-cereal fruit feeding device.

[0067] Non-cereal fruits, such as grape berries, are conveyed by means of a conveyor, the conveyor's conveying speed ejects the berries at its end along a known trajectory.

[0068] Preferably, the non-cereal fruit sorting apparatus according to the present invention may be characterized in that said apparatus is configured to sort fruits as described above in the method according to the invention, for example chosen from tomatoes, grapes, strawberries, raspberries, currants, cherries, blackberries, lingonberries, black currants, aronia berries, cranberries, elderberries and blueberries, preferably grapes such as red grapes.

[0069] The non-cereal fruit sorting apparatus according to the present invention comprises in particular at least one radiation system configured to generate one or more electromagnetic radiations.

[0070] In a particular embodiment, the non-cereal fruit sorting apparatus according to the present invention comprises two radiation systems configured to emit at least two electromagnetic radiations.

[0071] The non-cereal fruit sorting apparatus according to the present invention further comprises at least one detection zone configured to measure and optionally analyze the return signals from the one or more radiation systems. A detection zone and two radiation systems configured so that the return signals reach said detection zone, may constitute a non-cereal fruit maturity analysis assembly. The non-cereal fruit sorting apparatus according to the present invention may comprise several non-cereal fruit maturity analysis assemblies each arranged to expose said non-cereal fruits at different angles.

[0072] In a particular embodiment, the distance of the detection zone from irradiated fruit is adapted to have both the largest zone for capturing return signals, without the detection means being subject to hazards linked to its proximity to the fruit (spraying of juice, dirt or other).

[0073] Furthermore, each analysis assembly may comprise a device for analyzing the received signals, such as an electronic card or an electronic processor, or a device such as a computer.

[0074] The apparatus for sorting non-cereal fruits according to the present invention comprises in particular a system for separating said fruits which operates according to the return signals, which may take the form of a means for supplying compressed air or even an articulated arm allowing the expulsion of said undesirable fruits.

[0075] Thus, the sorting apparatus according to the present invention implements the non-destructive method of determining the maturity and quality of a non-cereal fruit according to the present invention.

[0076] Furthermore, the sorting apparatus according to the present invention is adapted to the size of the sorted fruits. The size of these fruits may be, for example in the case of grapes, of the order of 10 to 20 mm in diameter, preferably 11 to 15 mm in diameter.

[0077] • Analysis device, in particular portable:

[0078] In a particular embodiment, the subject of the present invention can be applied to an analysis device, in particular portable, of plants in the field. For example, advantageously, the method for monitoring the state or evolution of a culture according to the present invention can be applied to a portable device according to FR2916850A1 or of an equivalent type.

[0079] Indeed, the device described in FR2916850A1, which by its construction and its mode of use, is put in contact with the plant, and in particular with the fruits, guarantees to always have the same excitation-target distance. The apparatus according to the present invention can therefore have the same characteristics as those described in FR2916850A1, adapted to expose the fruit(s) analyzed to the two wavelengths under the conditions as described above.

[0080] In particular, such a (portable) device comprises a self-powered portable housing having a first face carrying user interface means and a second face called the measurement face directed towards a measurement direction, this measurement face comprising on the one hand on its periphery a surface carrying the excitation means and on the other hand in its center a part extending in the measurement direction, enclosing at least a part of the detection electronics and carrying the detection means on its face on the side of the measurement direction.

[0081] In a particular embodiment, the (portable) apparatus according to the present invention comprises a spatial positioning device, such as a GPS, which makes it possible, for example, to make a precise link between the measurements taken and a crop or part of a crop.

[0082] Furthermore, in the context according to the present invention, the radiation systems of a (portable) apparatus according to the present invention comprise one or more sources based on light-emitting diodes (LEDs). The advantage of LEDs is a limitation of energy consumption.

[0083] In a particular embodiment, such an apparatus comprises at least one excitation emitter fixed on a radiator element whose shape determines the position and orientation of said emitter or detector.

[0084] In particular, the portable device comprises management means arranged to provide at least one fluorescence measurement, for example radiation at 650 nm - called "excitation", and at least one detection excitation (for example at 750 nm, used in reflection) determined to be combined and correlated with each other, as described herein.

[0085] Preferably, the management (and processing) means are arranged to: - control the pulse radiation system(s), - detect the fluorescence peaks generated by these pulses using detectors, which can be amplified to achieve the rejection of ambient light by a feedback loop, and - process the detected fluorescence signal and provide the fluorescence measurement.

[0086] Preferably, the management (and processing) means are arranged to: - control the pulse radiation system(s), - detect the reflection peaks generated by these pulses using detectors, which can be amplified to achieve the rejection of ambient light by a feedback loop, and - process the detected reflection signal.

[0087] Preferably, the management and processing means are arranged to: - control the radiation system(s) according to a frequency including modulation, and - process the fluorescence detection signal, for example by phase demodulation so as to obtain rejection of ambient light, and - provide the fluorescence measurement.

[0088] Preferably, the management and processing means are arranged to: - control the radiation system(s) according to a frequency including modulation, - process the reflection detection signal, for example by phase demodulation so as to obtain rejection of ambient light, and - provide the reflection measurement.

[0089] Thus, the apparatus (in particular portable) according to the present invention allows the implementation of a method configured for monitoring the evolution of a crop over time, characterized in that it allows the comparison of a plurality of measurements carried out over time for a given compound in the same plant or on the same plot.

[0090] Preferably, the method is implemented to evaluate the ripening or the quality or the composition of fruits or vegetables by measuring the content of at least one ripeness marker, such as an anthocyanin.

[0091] Preferably, the method is implemented so that at least one measurement of a plurality of plants is carried out on the fly, as the measuring device (in particular portable) according to the present invention moves. FIGURES

[0092] Embodiments of the present invention will be described below, by way of non-limiting examples, with reference to the appended figures in which:

[0093] [Fig. 1] is a schematic representation of the sorting method according to the present invention applied to a non-cereal fruit sorting line;

[0094] [Fig.2] represents a phase diagram for the exposure of grapes.

[0095] With reference to [Fig.l], grapes 1 are scrolled (scrolling represented by arrow A) by means of a conveyor 2, the scrolling speed of the conveyor can eject the berries at its end along a known trajectory, or grape 1 can be analyzed on conveyor 2 (not shown here).

[0096] A first electromagnetic wave 3 is focused on the berries at the location where they pass in front of the camera 4. The first electromagnetic wave is produced by a first emitter 5. A second electromagnetic wave 6 is focused on the berries at the location where they pass in front of the camera 4. The second electromagnetic wave is produced by a second emitter 7. The return signals 8 are thus captured by the camera 4. Thus, to respond to the implementation of the method for measuring emitted fluorescence (750 nm) and reflection (750 nm), the emitters 5, 7 are switched on sequentially so that the camera 4 successively measures the fluorescence due to the excitation of each illumination and the reflection signal.

[0097] Thus, the camera 4 can be in the particular case represented as an infrared monochrome camera provided with a 750 nm bandpass filter.

[0098] The objective of the camera 4 can be equipped with a bandpass filter to specialize it on the wavelength of the desired fluorescence.

[0099] The vision axis of the camera 4 can be perpendicular to the plane of the conveyor 2 which sets the grape 1 in motion (represented by the arrow A).

[0100] The sensor of the camera 4 can be oriented in its length so as to be transverse to the axis of movement of the conveyor 2.

[0101] The lens of the camera 4 can allow the sharpness of the camera 4 to be adjusted at the focal length.

[0102] One of the emitters 5,7 can be low-pass filtered to cut off the electromagnetic waves specific to fluorescence and thus be totally dedicated to providing a reflection return signal 8.

[0103] The transmitters 5, 7 can be sized to illuminate all the bays 1 moving along the width of the conveyor 2. The camera 4 can be equipped with a lens so as to receive return signals 8 across the entire width of the conveyor 2.

[0104] The focal length and intensity of the exposure are sized to position the 5,7 emitters at a good distance from the grape.

[0105] The emitters 5,7 may comprise LEDs for providing the desired electromagnetic waves. These LEDs may be arranged so as to obtain exposure on a continuous line on a single face of the exposed fruits.

[0106] The exposure(s) are adjustable in orientation to converge them in a single location on the known trajectory of the non-cereal fruit.

[0107] The transmitters 5,7 and the camera 4 can be sufficiently shielded from radiation from the external environment so as not to affect the measurements.

[0108] The emitters 5,7 can be configured to illuminate at least the width of the conveyor 2 which transports the fruit to be sorted.

[0109] The transmitters 5,7 may be above the conveyor 2 or shortly after the exit of the conveyor 2.

[0110] The transmitters 5,7 can be offset so as not to be in the field of the camera 4.

[0111] An ejection means 9, such as a nozzle, makes it possible to remove unwanted fruit or objects. It is indeed an optional advantage of the present invention to be able to identify unwanted objects if desired by comparing the image obtained following the exposure of the fruit passing in front of the camera 4 and the expected general outline of the fruit to be sorted. Other sorting systems based for example on color or shape can also be added to increase the accuracy of the sorting.

[0112] Here, it is an air jet 10 which allows the ejection of the unwanted fruit 11.

[0113] There are as many ejection means 9 as necessary so that sorting can be operational across the width of the conveyor.

[0114] Thus, the sorted fruits 12 that we wish to keep are isolated and recovered.

[0115] A management system is implemented to manage the sequencing of the illumination and the synchronization of the fluorescence measurement. Thus, in [Fig.2] is represented a phase diagram particularly well adapted to the sorting chain according to [Fig.l] in which:

[0116] PI represents an excitation period N°L PI can be used to define the resolution of the system;

[0117] P2 represents an excitation period No. 2;

[0118] Tl represents an excitation duration No. 1;

[0119] T2 represents an excitation duration No. 2, the most sensitive (absorbed), could be adjusted to ensure sufficient signal;

[0120] T3 represents a time available for noise measurement; and

[0121] DI represents a phase shift to ensure synchronization of the reference and the measurement.

[0122] The excitation time of the wavelength at 625 nm is between 100 and 300 pS, preferably 240 pS. The total cycle time is between 300 and 600 pS, preferably 500 pS.

[0123] The sequencing of the excitations must be able to allow the measurement in several places of the same fruit to be sorted (here grapes) which is moving at a known speed. The number of measurements carried out on a fruit to be sorted of average size defines the resolution of the system. This resolution is in line with the desired level of precision and the desired fruit flow rate.

[0124] The duration of the exposure in the wavelengths and their periods can be managed by an automaton adapted for industrial vision.

[0125] The phase shift between several exposure wavelengths can also be managed by the automaton.

[0126] The result of the processing is rendered in a simple form that can be interpreted by the operator so as to enable him to adjust the selection to be made.

[0127] A juxtaposition of images from emitted fluorescence and images from reflection makes it possible to identify and quantify berries with low chlorophyll levels.

[0128] The device may provide for the elements with a low level of chlorophyll to carry out an image analysis in order to discriminate the berries from the other elements of the harvest.

[0129] It is advantageous then that the management system controls the sorting means in such a way as to carry out the selection set by the operator. This setting can be modified at any time during operation.

[0130] The operator may determine a selection threshold beforehand via an appropriate analysis, either by first taking a sample analyzed by other means, or by assessing the quantitative distribution between several batches constituted and by adjusting the selection threshold.

[0131] EXAMPLES

[0132] By way of illustration, absorbance measurements according to the present invention made in spectrophotometry at 520 (i.e. a wavelength consistent with the anthocyanin contents) on grapes were carried out.

[0133] Thus, differences between more ripe and less ripe batches could be measured with the method according to the present invention:

[0134] Table 1: results obtained in 2020 Grape variety Percentage difference between the ripest and least ripe fruits Merlot +25.5% Cabernet 1 +13.6% Cabernet 2 +12.6%

[0135] NB: the 2020 method differed from that implemented in 2021 in that the classification of the fruits was done manually according to the results given by the method. The passage of the fruits was done manually one by one in the system where it was excited according to the appropriate wavelength, the order of passage kept for each fruit, the method was applied manually to each fruit when viewing the recorded images of its Fluorescence. The Fluorescence due to each excitation was recorded separately.

[0136] Table 2: results obtained in 2021 Grape variety Percentage difference between the ripest and least ripe fruits Merlot 1 +48% Merlot 2 +37% Cabernet 1 +58%

[0137] The 2021 process showed a better overall level of maturity on the grapes tested compared to those of 2020.

[0138] The 2021 measuring bench was fully automated up to the physical classification of the fruits according to the process.

[0139] Analyses of anthocyanin content in finished wine from grapes classified in this way during the 2021 trials show the same trends.

Claims

Claims

1. Non-destructive method for determining the maturity and quality of a non-cereal fruit comprising at least two steps of exposing said fruit to at least two different electromagnetic radiations and measuring their return signals, in which: - one of the steps of exposing said fruit comprises providing at least one wavelength capable of causing a chlorophyll fluorescence signal and a measurement, where appropriate, of said chlorophyll fluorescence signal;and - one of the steps of exposing said fruit to at least one electromagnetic radiation comprises the provision of at least one selected wavelength, capable of generating a reflection signal on said fruit, and a measurement, where appropriate, of said reflection signal, characterized in that said at least one wavelength capable of causing chlorophyll fluorescence is between 590 nm and 660 nm, in that the measurements of the chlorophyll fluorescence signal and of the reflection signal are carried out by the same sensor, said sensor being a camera provided with a bandpass filter and in that on the one hand, the provision of at least one wavelength capable of causing a chlorophyll fluorescence signal, and on the other hand the provision of at least one selected wavelength capable of generating a reflection signal on said fruit, are sequenced and / or synchronized.;

2. Method according to claim 1, characterized in that the bandpass filter is calibrated at 750 nm.

3. Method according to any one of claims 1 or 2, characterized in that on the one hand, the supply of at least one wavelength capable of causing a chlorophyll fluorescence signal, and on the other hand the supply of at least one chosen wavelength capable of generating a reflection signal on said fruit, are sequenced and / or synchronized, with at least one pause time to allow the measurement of the background noise.

4. Method according to any one of claims 1 to 3, characterized in that said at least one wavelength chosen to generate a reflection on said fruit is chosen with a wavelength significantly greater than the excitation wavelength of chlorophyll.

5. Method according to claim 5 characterized in that the wavelength significantly greater than the excitation wavelength of the chlorophyll is between 700 nm and 900 nm, preferably 750 nm plus or minus 10 nm, and in that said at least one wavelength capable of causing fluorescence of the chlorophyll is 625 nm plus or minus 10 nm.

6. Method according to any one of claims 1 to 5, characterized in that the non-cereal fruit contains at least one pigment chosen from lycopene, beta-carotene, anthocyanin and lutein, preferably anthocyanin and / or lycopene.

7. Method according to any one of claims 1 to 5, characterized in that the non-cereal fruit is chosen from a tomato, a grape, a strawberry, a raspberry, a redcurrant, a cherry, a blackberry, a lingonberry, a blackcurrant, an aronia berry, a cranberry, a black elderberry and a blueberry, preferably a grape.

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