WO2022269647A1

WO2022269647A1 - Optical inspection apparatus and corresponding method

Info

Publication number: WO2022269647A1
Application number: PCT/IT2022/050176
Authority: WO
Inventors: Roberto MICHIELI; Massimo BISAZZA
Original assignee: Eppos S.R.L.
Priority date: 2021-06-24
Filing date: 2022-06-21
Publication date: 2022-12-29
Also published as: IT202100016571A1

Abstract

The invention concerns an optical inspection apparatus (10) for detecting the integrity of one or more objects (300) which are disposed on a support (50), comprising an emitter unit (11) and at least one optical assembly (12, 12a, 12b) configured to acquire at least IR images of the support (50) and of said objects (300), said emitter unit (11) being able to be disposed under said support (50) and said at least one optical assembly (12, 12a, 12b) being able to be disposed above said support (50). The invention also concerns a method for using an optical inspection apparatus (10).

Description

“OPTICAL INSPECTION APPARATUS AND CORRESPONDING

METHOD”

FIELD OF THE INVENTION

The present invention concerns an optical inspection apparatus, and a corresponding method, able to detect the integrity of a plurality of objects, moved by a conveyor, through the acquisition and analysis of images.

The present apparatus can be applied in the industrial field, in a particularly advantageous way in those fields in which it is required to process a large number of objects in a short time to detect their cleanliness and integrity. A preferential application is the monitoring of eggs to detect dirty, broken, cracked and/or micro- cracked eggs, for example in the preparation chain for packaging them.

BACKGROUND OF THE INVENTION

It is known that optical inspection systems exist, based on matrix video cameras that detect images in the visible range in order to analyze the cleanliness and integrity of objects. Their main disadvantage is that they do not detect cracks that are not evident or are hidden by surface dirt or micro-fractures.

Usually these systems - to compensate for this deficiency - are associated with other devices, such as mechanical systems, or probes, which, by lightly hitting the object, make a more accurate and complete analysis possible. These systems are very expensive and get dirty easily, since they necessarily have to come into contact with the object, and therefore require frequent maintenance, increasing management costs.

Alternatively, optical inspection systems based on matrix video cameras can comprise infrared (IR) back light panels with diffused light so as to highlight the fractures. However, these systems are affected by IR light which, in areas not covered by the objects, reaches the cameras directly. False positives can therefore be detected, due to over-illumination and possible reflections toward the camera.

For example, in the case of eggs, these can be positioned according to a matrix pattern on a roller conveyor provided for an IR illumination segment. In correspondence with the fractures, zones are detected that are lighter than the intact areas of the egg.

In correspondence with positions of the matrix of the roller conveyor that are not occupied by eggs or passing between an egg and support elements of the roller conveyor, for example in the case in which a high intensity IR light is used to better illuminate even the micro-fractures, the IR light can reach the cameras directly. These effects are shown in fig. 1 , which shows a support 450, in the particular case the support 450 being a part of a roller conveyor 461 , in which the light emitted by the infrared panel 415 of a known optical inspection system in correspondence with a housing space not occupied by eggs and reflections 401 on the tracks 462 and separator rollers 463 of the support 450 are visible.

To overcome these problems, a low intensity IR light is usually used. Furthermore, in the image analysis step, a “crop” is usually carried out, that is, the peripheral band of the image of the object is cut, in order to eliminate any reflections. In this case it is no longer possible to detect perimeter defects.

Document US-A-2009/201323 describes an apparatus for the visual examination of objects, in particular to determine the presence of fertilized eggs in the cells of a grid box for eggs that move on a conveyor.

Document CN 110455 806 A describes a device for the dynamic acquisition of images of eggs.

Document CN 213 239 954 U describes an apparatus for the online detection and classification of eggs, in particular to detect surface defects of eggs on the basis of image processing.

There is therefore a need to perfect an optical inspection apparatus which can overcome at least one of the disadvantages of the state of the art.

To do this, it is necessary to solve the technical problem of avoiding over illumination and possible reflections of the IR illumination that reach the camera, causing false positives.

One purpose of the present invention is to provide an optical inspection apparatus, and to perfect a corresponding method, for detecting the cleanliness and integrity of objects.

One purpose is also to provide an apparatus able to process a large number of objects in a short time.

Another purpose of the present invention is to use the entire detected image, in order not to have to eliminate peripheral bands of the image, increasing the reliability of the inspection result. Another purpose is therefore to reduce processing waste, due to the elimination of objects in good condition but erroneously not evaluated as such, to reduce the need to eliminate the damage caused in the subsequent processing steps, for example with cleaning/replacement of other objects or parts of the processing plant damaged by flawed objects, or to avoid sending onto the market damaged objects, with damage to one’s image or suchlike.

Another purpose of the present invention is to provide an optical inspection apparatus with a reduced bulk, which can therefore also be integrated into pre existing processing lines, in which the available space can be limited. The Applicant has devised, tested and embodied the present invention to overcome the shortcomings of the state of the art and to obtain these and other purposes and advantages.

SUMMARY OF THE INVENTION

The present invention is set forth and characterized in the independent claims. The dependent claims describe other characteristics of the present invention or variants to the main inventive idea.

In accordance with the above purposes and in order to resolve the technical problem disclosed above in a new and original way, also achieving considerable advantages compared to the state of the prior art, an optical inspection apparatus according to the present invention, for detecting the integrity, and possibly the state of cleanliness, of a plurality of objects which are moved by a conveyor provided with a support for moving the objects, comprises an infrared emitter unit and at least one optical assembly.

The emitter unit is able to be disposed below the support. The emitter unit is provided with a plurality of independent point-type infrared sources, able to be activated selectively and autonomously, which are configured to emit IR radiations at least toward the support.

The at least one optical assembly is able to be disposed above the support. The emitter unit and the at least one optical assembly are able to be positioned respectively on the opposite sides of the support.

The at least one optical assembly is configured to detect at least IR images, and possibly white light images, of the support and of the objects present on the support. In the present description, by white light we mean a light comprising all the radiations in the visible range. In other words, white light is a combination of lights of different wavelengths in the visible spectrum. The passage of white light through a prism divides it into the different colors of light that are observed in the visible spectrum between about 400 nm and about 780 nm. Therefore, white light is formed by a combination of different colors of lights that have wavelengths that cover a range of wavelengths from about 400 nm to about 780 nm. In particular, visible white light has a wavelength peak between about 500 and 550 nm.

By white light image we mean an image acquired in conditions in which the objects are illuminated by white light, either natural or provided by special white light illuminators. In other words, a white light source that illuminates objects to obtain a white light image can be natural or artificial, using special white light illuminators.

By IR image we mean an image acquired in conditions in which the objects are illuminated by infrared radiation.

The apparatus comprises a control unit configured to detect the presence or absence of objects in housing spaces of the support in which the objects can be positioned.

The control unit can be configured to detect the presence of the objects preferably by analyzing a white light image acquired by the at least one optical assembly.

Alternatively, the control unit can be configured to detect the presence of objects by analyzing a signal of presence/absence of the object.

The control unit is configured to command the selective switching on of infrared sources of the optical assembly which are disposed aligned below spaces for housing the objects on the support, depending on the presence or absence of the objects.

By doing so, there is at least achieved the advantage of being able to automatically switch off the infrared sources corresponding to spaces in which no objects are present. The radiation emitted by the infrared sources cannot therefore directly reach the optical assembly, over-illuminating it and therefore potentially blinding it.

The control unit is configured to command the acquisition of one or more IR images by the at least one optical assembly and analyze the one or more IR images in order to detect the integrity of the objects.

Advantageously, it is possible to increase the brightness of the infrared sources, thus optimizing the sensitivity of the apparatus and the probability of detecting cracks and micro-fractures.

The apparatus can comprise collimator members which are able to be positioned between the infrared sources and the corresponding spaces for housing the objects. The collimator members can receive IR radiations from the sources and supply them at exit in collimated form toward the objects.

Advantageously, the radiation beam is concentrated in correspondence with the object, preventing the radiation from passing beyond the object in the points where it does not fully cover its housing space, and also preventing potential reflections on the support. It is therefore possible to use the entire IR image of the object detected, without eliminating the peripheral bands.

By eliminating the disturbances that give rise to false positives, it is possible to increase the reliability and speed of the inspection using an inspection apparatus of the optical type effectively.

There is also a reduction in the number of interventions by operators to block the processing chain because of possible damages caused by flawed objects that have been erroneously considered valid, such as for example the breaking, in the packaging step, of a previously cracked egg, with consequent damage to other eggs or suchlike.

The control unit can be configured to receive and analyze one or more white light images supplied by the optical assembly in order to detect the presence or absence of one or more of the plurality of objects on the support. It is therefore not necessary to use additional devices, such as sensors or detectors, which require more maintenance, and any electronic boards for signal conditioning and acquisition and suchlike.

Advantageously, the apparatus can comprise only one optical assembly: in this way it is possible to reduce the overall dimensions of the apparatus itself, which can also be integrated into pre-existing processing plants.

DESCRIPTION OF THE DRAWINGS

These and other aspects, characteristics and advantages of the present invention will become apparent from the following description of some embodiments, given as a non-restrictive example with reference to the attached drawings wherein:

- fig. 1 shows some disadvantages of optical inspection systems used in the state of the art; - fig. 2 shows a perspective view of an optical inspection apparatus, during use, according to some embodiments;

- fig. 2a shows a section view of the optical inspection apparatus according to the plane Ila-IIa of fig. 2;

- fig. 3 shows a section view of an optical inspection apparatus, during use, according to other embodiments;

- fig. 4a shows a top view of an area detected by the optical inspection apparatus of fig. 2, during use;

- fig. 4b shows a top view of the infrared sources of fig. 4a, during use;

- fig. 5 shows a schematic block representation of an optical inspection apparatus, during use, according to other embodiments.

We must clarify that in the present description the phraseology and terminology used, as well as the figures in the attached drawings also as described, have the sole function of better illustrating and explaining the present invention, their function being to provide a non-limiting example of the invention itself, since the scope of protection is defined by the claims.

To facilitate comprehension, the same reference numbers have been used, where possible, to identify identical common elements in the drawings. It is understood that elements and characteristics of one embodiment can be conveniently combined or incorporated into other embodiments without further clarifications. DESCRIPTION OF SOME EMBODIMENTS

In this document we will describe a preferential, but not exclusive, application relating to the control of food products, and in particular of eggs, in order to analyze their state of integrity and, possibly, cleanliness. It is understood that the present invention is generally applicable to any application in the industrial, food or other fields, in which there is a need to verify the state of integrity and possibly cleanliness of objects 300.

With reference to figs. 2, 2a, 3, 4a, 4b, an optical inspection apparatus 10 for detecting the state of integrity of a plurality of objects 300, for example eggs, is described. In particular, these objects 300 can be positioned on a matrix support 50 and moved by a conveyor 60.

The apparatus 10 comprises:

- an emitter unit 11, provided with a plurality of independent point-type infrared sources 15, able to be activated selectively and autonomously, which are configured to emit IR radiations;

- at least one optical assembly 12, 12a, 12b; and

- a control unit 13.

The emitter unit 11 is able to be disposed under the support 50.

The sources 15 are configured to selectively emit the IR radiations toward the support 50.

With reference to figs. 2 and 2a, the apparatus 10 can comprise only one optical assembly 12, configured for the acquisition of all the necessary IR and white light images. In figs. 2 and 2a, the cone of vision of the optical assembly 12 is represented with C.

With reference to fig. 3, the apparatus 10 can comprise two optical assemblies 12a, 12b. In this case, the optical assembly 12a, 12b can be configured to detect white light images, and the optical assembly 12b can be configured to detect IR images and possibly white light images. In fig. 3, the cones of vision of the optical assemblies 12a, 12b are represented with Cl, C2.

For the acquisition of the IR images, the objects 300 are understood to be illuminated by infrared sources 15. During the acquisition of the white light images, on the other hand, the objects 300 are not illuminated by the infrared sources 15.

The optical assembly 12, 12a, 12b is configured to detect images of the support 50 and of the plurality of objects 300 present therein.

The optical assembly 12, 12a, 12b can comprise an optical detection device 21, such as a video camera, a camera or suchlike. Preferably, it comprises a matrix video camera.

The optical assembly 12, 12a, 12b can comprise one or more white light illuminators 20 (figs. 2, 2a, 3). The illuminators 20 can be used to illuminate the objects 300 in order to identify their position and possibly to detect their state of cleanliness and the presence of macroscopic defects. By macroscopic defects we mean cracks and fractures that are clearly visible, because of their extension or severity.

According to some embodiments, the apparatus 10 can comprise a sustaining element 14 configured to sustain the emitter unit 11 and the at least one optical assembly 12, 12a, 12b in a fixed position with respect to the support 50.

The sustaining element 14 can be a bar, a beam system or any element on which the emitter unit 11 and the at least one optical assembly 12, 12a, 12b can be attached in a stable manner.

The emitter unit 11 and the at least one optical assembly 12, 12a, 12b can be positioned, by means of the sustaining element 14, respectively on the opposite sides of the support 50, with respect to a plane PI in which the support 50 develops in its two preponderant sizes. As shown in fig. 2, the plane PI in which the support 50 develops can be the horizontal plane and the emitter unit 11 and the at least one optical assembly 12, 12a, 12b can be disposed respectively below and above the support 50.

The emitter unit 11 and the optical assembly 12, 12b are able to be positioned one in front of the other, in such a way that the emitter unit 11 emits infrared radiation in the direction of the optical assembly 12, 12b.

The matrix support 50 can be a support that has a structure with solids and voids, which are defined by separation elements 51. The objects 300 can be positioned in correspondence with such voids, or housing spaces 52.

The support 50 can be comprised in a conveyor 60 that conveys the objects 300 in a direction of advance LI . The conveyor 60 can be a conveyor belt, in particular it can be a conveyor belt provided with a roller conveyor 61, which is understood as a structure that has separation elements 51 such as longitudinal tracks 62 and separator rollers 63 that are orthogonal to the tracks 62, in order to define a matrix. The tracks 62 can be fixed and the separator rollers 63 can rotate on an axis A1 thereof, thus allowing to make the objects 300 rotate.

According to some embodiments, the emitter unit 11 can comprise a structure 16 for coupling the sources 15, such as a panel, a metal or polymeric structure or suchlike.

The sources 15 can be lamps, LEDs or suchlike, preferably they are LEDs. In one variant, the sources 15 can be created by means of a single light source provided with a selection element, for example a panel provided with elements, such as diaphragms, darkening filters or suchlike, which can be commanded in order to allow the passage of IR radiation only where and when desired.

According to some embodiments, the apparatus 10 can comprise collimator members 17 which are able to be positioned between the sources 15 and corresponding spaces 52 for housing the objects 300.

The collimator members 17 can be suitably configured and positioned to direct the IR radiation of the sources 15 toward the corresponding housing spaces 52, in particular within the area occupied by the objects 300.

The collimator members 17 can receive the IR radiations from the sources 15 and supply them in collimated form to the objects 300.

The collimator members 17 can be diaphragms with a through hole, adjustable or not, converging lenses or suchlike. Preferably, the collimator members 17 are converging lenses. Even more preferably, they are lenses converging between 11 and 14 degrees. Advantageously, the upper limit of such interval (14 degrees) is relative to the maximum amplitude of the beam of the IR radiation on the object 300, and its lower limit (11 degrees) is relative to the minimum amplitude needed to guarantee a sufficient distribution of the IR radiation on the object 300 itself.

In the case of analyzing eggs, the angle of collimation of the collimator members 17 is smaller than 20°, preferably smaller than 15°, even more preferably no larger than 13°. In particular, the angles of collimation are indicated for a distance of approximately 30 mm between the collimator member 17 and the corresponding object 300, where by distance we mean the average space between an object 300, of an average size in the case of objects 300 of different sizes, and the upper part - intended as facing toward the object 300 - of the collimator member 17.

The control unit 13 can be configured to detect the presence or absence in the support 50 of one or more of the plurality of objects 300, and to command the switching on or off of the sources 15 that correspond to the spaces 52 for housing the objects 300.

The unit 13 can be configured to receive IR images and white light images from the at least one optical assembly 12, 12a, 12b and analyze them.

The unit 13 can be configured to detect the integrity of the objects 300 by analyzing the IR images. The unit 13 can be configured to detect the presence of the objects 300 by analyzing the white light images.

In some variants, the unit 13 can be configured to receive data from sensors for the presence of the object 300, such as ultrasonic, optical, capacitive sensors or suchlike, not shown in the drawings. The unit 13 can therefore be configured to detect the presence of the objects 300 by means of such data.

The unit 13 can also be configured to evaluate the cleanliness of the objects 300 and/or the presence of macroscopic defects therein by analyzing the white light images.

The unit 13 can comprise one or more processing devices 18 and one or more storage devices 19.

The processing devices 18 can be any form whatsoever of controller, microprocessor, computer processor or suchlike that can be used in the IT field to process data, advantageously in the context of image processing.

The storage devices 19 can be connected to the processing devices 18 and be among those commercially available, such as a random access memory (RAM), a read only memory (ROM), a floppy disk, a hard disk (HARD DISK), mass memory, or any other form of digital storage whatsoever, local or remote or electronic database.

The devices 19 can be configured to store one or more algorithms for processing the white light images which can be executed by the processing devices 18 in order to detect the state of cleanliness of the objects 300 and/or the presence of macroscopic defects therein.

The devices 19 can be configured to store one or more analysis algorithms configured to detect the presence or absence of the objects 300 in the housing spaces 52. The one or more analysis algorithms can use sensor data and/or white light images supplied by the at least one optical assembly 12, 12a, 12b.

The devices 19 can be configured to store one or more IR image processing algorithms in order to detect the integrity of the objects 300 by identifying cracks, micro-fractures and/or breaks that are not evident or are hidden by surface dirt.

The devices 19 can be configured to store one or more control algorithms to command the at least one optical assembly 12, 12a, 12b and possibly the sensors.

The devices 19 can be configured to store one or more control algorithms to command the switching on and/or switching off of the sources 15. As shown in figs. 4a and 4b, the sources 15a are switched on in correspondence with the objects 300 present, while the sources 15b are switched off in correspondence with the empty housing spaces 52 of the support 50.

The one or more control algorithms can be configured to determine the translation speed of the object 300.

The one or more control algorithms can be configured to calculate the translation speed by processing white light images acquired by the at least one optical assembly 12, 12a, 12b. Alternatively, the control unit 13 can be configured to acquire data from sensors, for example speed or position sensors such as encoders or suchlike, or operating data of the plant for processing the objects 300 or suchlike.

The one or more control algorithms can be configured to command the acquisition of white light images and/or IR images, to command the switching on/off of the sources 15 and/or to command the at least one optical assembly 12, 12a, 12b on the basis of the translation speed.

The unit 13 can also be configured to automatically command the rejection of the flawed objects 300.

According to one embodiment, the apparatus 10 can be configured to acquire images comprising at least two subsequent groups of objects 300, positioned in correspondence with at least two subsequent supports 50. Advantageously, in this way at least two subsequent IR images, and possibly white light images, of a same group of objects 300 can be acquired with a same apparatus 10. As shown for example in fig. 5, the apparatus 10 can be configured to acquire images comprising three subsequent groups of objects 300.

In the embodiment as above, the optical assembly 12 can have a cone of vision C wide enough to insist on at least two subsequent supports 50.

In an equivalent way, in an embodiment not shown in the drawings, for an apparatus 10 with two optical assemblies 12a, 12b, these can have cones of vision Cl, C2 sufficiently wide to each one of them insist on at least two subsequent supports 50.

Advantageously, the objects 300 in correspondence with one support 50, subsequent to the first, can be positioned in a configuration that is rotated with respect to the position in which they were in previous time intervals, during which they were in correspondence with a previous support 50. In this way, the state of integrity and possibly of cleanliness can be evaluated over the entire surface of the objects 300.

For example, in the case of eggs positioned on a roller conveyor 61, the apparatus 10 can be configured to acquire images comprising three subsequent groups of eggs, positioned in correspondence with three subsequent supports 50. In subsequent time intervals, the eggs can be rotated by 120° in correspondence with each subsequent support 50.

The operation of the optical inspection apparatus 10 described heretofore, which corresponds to the method according to the present invention, comprises the steps of:

- detecting the presence or absence of one or more objects 300 in spaces 52 for housing the objects 300 on the support 50, as a function of a first white light image acquired by at least one optical assembly 12, 12a, 12b, or of a signal of presence/absence of the object 300;

- commanding the selective switching on of point-type infrared sources 15 of an emitter unit 11 which are disposed aligned below the spaces 52 for housing the objects 300 on the support 50 as a function of the presence/absence of the objects 300 in the housing spaces 52;

- acquiring at least one IR image of the support 50 and of one or more objects 300, which are present on the support 50 and are illuminated by the sources 15, by means of at least one optical assembly 12, 12a, 12b which is able to be positioned on the opposite side of the support 50 with respect to the emitter unit 11 ; and

- analyzing the IR image in order to detect the integrity of the one or more objects 300.

The IR image of the objects 300 illuminated by the infrared sources 15 also allows to identify fractures, cracks and breaks that are not immediately visible, since they are of limited extension or severity.

The method can provide to take a maximum of 100 ms for the step of acquisition and analysis of the IR image as above.

The method can provide to power the sources 15 with an alternating current. In this way, the consumption of electrical energy is reduced; it is also possible to increase the useful life of the sources.

According to some embodiments and with reference to figs. 2, 2a, the method can provide, in an initial step, to switch off all the sources 15 and to acquire a first white light image by means of the optical assembly 12. The method can provide to illuminate the objects 300 by means of one or more illuminators 20 in order to improve the quality of the white light image. The method can then provide to switch off the one or more illuminators 20 during the acquisition of the IR image of the objects 300 illuminated by the sources 15.

The method can provide to analyze the first white light image in order to detect the state of cleanliness of the objects 300 and/or the presence of macroscopic defects therein.

The method can provide to use the first white light image in order to detect the presence or absence, in the housing spaces 52, of one or more of the plurality of objects 300. The method can provide to terminate the step of acquiring and analyzing the first white light image within an interval of 120 ms, preferably of 100 ms.

The method can provide to keep the sources 15 switched off and acquire a second white light image for the identification of the perimeter of the objects 300.

The method can then provide, on the basis of the translation speed of the object 300, to superimpose the previously identified perimeter on the IR image of the objects 300 illuminated by the sources 15 and to limit the analysis to the area comprised in the perimeter.

The method can also provide to adjust collimator members 19 of the apparatus 10 in order to collimate the first light radiations received from the sources 15 within the perimeter of each object 300 present.

The method can provide to take, for the step of acquiring and analyzing the second white light image, a maximum of 80 ms, preferably 35 ms, even more preferably 30 ms.

In one variant, with reference to fig. 3, in which the optical inspection apparatus 10 comprises two optical assemblies 12a, 12b, the method can provide to acquire, by means of the first optical assembly 12a, a first and possibly a second white light image of the support 50 and of the plurality of objects 300, which are present on the support 50 and are not illuminated by the sources 15. It can then provide to acquire, by means of the second optical assembly 12b, an IR image of the support 50 and of the plurality of objects 300, which are present on the support 50 and are illuminated by the sources 15. In this case, during the acquisition of first and possibly second white light images, the sources 15 can also be kept switched on.

Advantageously, the method can provide to carry out the steps described above without modifying the sliding speed of the conveyor 60.

The method can provide to carry out the steps described above in an interval of at most 600 ms, preferably at most 480 ms.

According to some embodiments, the method can provide to acquire images comprising at least two subsequent groups of objects 300, positioned in correspondence with at least two subsequent supports 50. In this configuration, the apparatus 10 can acquire at least two subsequent IR images, and possibly white light images, of the objects 300. In each subsequent IR image, and possibly white light image, the objects 300 can be in a configuration that is rotated with respect to the configuration in which they were in the previous IR image, and possibly in the white light image.

In particular, the apparatus 10 can acquire a first IR image at a time tO, a second IR image at a time tl, possibly additional IR images at subsequent times ti. At the time tl the objects are located in correspondence with a subsequent support 50 and they can be rotated with respect to the position taken at the instant tO. In a possible time t2, the objects are located in correspondence with a subsequent support 50 and they can be rotated with respect to the position taken at the instant tl . Similarly, for the possible subsequent time intervals, the objects can be rotated with respect to the immediately preceding instants.

This can happen in a similar way for a possible first IR white light image and/or a possible second IR white light image.

For example, a preferred processing cycle for eggs transported on a conveyor belt provided with a roller conveyor can provide to:

- acquire, in a first step, a first white light image and analyze it in order to evaluate the presence of eggs in correspondence with the spaces for housing them on the roller conveyor, and possibly to evaluate the state of cleanliness and macroscopic defects, preferably taking an amount of time shorter than 100 ms;

- acquire, in a second step, a second white light image and analyze it in order to detect the perimeter of the eggs, preferably taking an amount of time shorter than 30 ms;

- acquire, in a third step, an IR image and analyze the area of the IR image within the perimeter of each egg in order to detect its integrity, preferably taking an amount of time shorter than 100 ms.

The three steps described above can be carried out by making the eggs pass through a single optical inspection apparatus 10.

The processing cycle can provide to take a maximum amount of time of 480 ms in order to complete all three processing steps.

After the interval of approximately 480 ms described above, it can be provided that the eggs are made to rotate, by the roller conveyor, by 120°.

The processing cycle can then provide to repeat the three steps described above another two times, making the eggs pass in two other optical inspection apparatuses 10, in correspondence with which the eggs can be rotated by 120° for each subsequent apparatus 10.

As an additional example, the possible values for the acquisition and analysis times of the white light images and IR images are reported below: a) first white light image acquisition time: between 25 and 45 ms; b) first white light image analysis time: between 40 and 70 ms. c) second white light image acquisition time: between 25 and 45 ms; d) second white light image analysis time: between 10 and 30 ms; e) IR image acquisition time: between 25 and 45 ms; f) IR image analysis time: between 10 and 30 ms.

These acquisition times are variable as a result of the compression algorithms that are used to optimize the data transmission band between the optical assembly 12 and the unit 13. Analysis times are variable as a result of the mathematical analyzes linked to the filters and artificial vision algorithms applied.

In general, the duration described above may vary, since the analysis is non- deterministic, as a function of various factors, such as the geometric variety of the objects 300, the coloring and suchlike.

It is clear that modifications and/or additions of parts may be made to the optical inspection apparatus 10 and to the corresponding method as described heretofore, without departing from the field and scope of the present invention, as defined by the claims.

It is also clear that, although the present invention has been described with reference to some specific examples, a person of skill in the art shall certainly be able to achieve many other equivalent forms of optical inspection apparatus, having the characteristics as set forth in the claims and hence all coming within the field of protection defined thereby.

In the following claims, the sole purpose of the references in brackets is to facilitate reading and they must not be considered as restrictive factors with regard to the field of protection defined by the claims.

Claims

1. Optical inspection apparatus (10) for detecting the integrity of a plurality of objects (300), moved by a conveyor (60) provided with a support (50) for said objects (300), said apparatus (10) comprising:

- an emitter unit (11), able to be disposed under said support (50) and provided with a plurality of independent point- type infrared sources (15), able to be activated selectively and autonomously, which are configured to emit IR radiations toward said support (50);

- at least one optical assembly (12, 12a, 12b), able to be disposed above said support (50) and configured to acquire at least IR images and possibly white light images; and

- a control unit (13) configured to detect the presence on the support (50) of one or more objects (300) as a function of a white light image acquired by said at least one optical assembly (12, 12a, 12b) or of a signal of presence/absence of said object (300), and to command the selective switching on of sources (15) of said at least one optical assembly (12, 12a, 12b) which are disposed aligned below spaces (52) for housing said objects (300) on said support (50) as a function of the presence/absence of the objects (300) in said housing spaces (52), and also to command the acquisition of one or more IR images by said at least one optical assembly (12, 12a, 12b), as well as to analyze said one or more IR images in order to detect the integrity of said objects (300).

2. Apparatus (10) as in claim 1, characterized in that it comprises collimator members (17), able to be positioned between said sources (15) and the corresponding housing spaces (52), configured to receive IR radiations from said sources (15) and supply them in collimated form to said objects (300).

3. Apparatus as in any claim from 1 to 2, characterized in that said control unit (13) is configured to command, in an initial step, the switching off of all said sources (15) and the acquisition of a first white light image, and to analyze said first white light image at least in order to detect the presence or absence, in the spaces of said housing (52), of said one or more objects (300).

4. Apparatus as in claim 3, characterized in that said white light image is an image acquired in conditions in which said objects (300) are illuminated by a white light.

5. Apparatus as in claim 3 or 4, characterized in that said control unit (13) is configured to command the acquisition, keeping said sources (15) switched off, of a second white light image for the identification of the perimeter of said objects (300), in order to superimpose the previously identified perimeter on said IR image of the objects (300) illuminated by the sources (15) and limit the analysis to the area comprised in the perimeter of said objects (300).

6. Apparatus (10) as in any claim hereinbefore, characterized in that it comprises a single optical assembly (12) and in that said optical assembly (12) comprises a color matrix video camera.

7. Apparatus (10) as in any claim hereinbefore, characterized in that it comprises a sustaining element (14) configured to sustain said emitter unit (11) and said at least one optical assembly (12, 12a, 12b) in a fixed position with respect to the support (50).

8. Apparatus (10) as in any claim hereinbefore, characterized in that said optical assembly (12, 12a, 12b) has a cone of vision (C, Cl, C2) wide enough to insist on at least two supports (50) that follow each other, said supports (50) comprising subsequent groups of objects (300), the apparatus (10) being configured to acquire at least two subsequent IR images, and possibly white light images, of a same group of objects (300).

9. Method for detecting the integrity of one or more objects (300), moved by a conveyor (60) provided with a support (50) for said objects (300), by means of an optical inspection apparatus (10), characterized in that said method comprises:

- detecting the presence, or absence, of one or more objects (300) in spaces (52) for housing said objects (300) on said support (50) as a function of a first white light image acquired by at least one optical assembly (12, 12a, 12b) or of a signal of presence/absence of said objects (300);

- commanding the selective switching on of point-type infrared sources (15) of an emitter unit (11) disposed under said support (50), which are independent and able to be activated selectively and autonomously, and are disposed aligned below said housing spaces (52), as a function of the presence/absence of the objects (300) in said housing spaces (52);

- acquiring, by means of said at least one optical assembly (12, 12a, 12b) disposed above said support (50), one or more IR images of the support (50) and of said one or more objects (300) illuminated by the sources (15); and

- analyzing said one or more IR images, by means of a control unit (13), in order to detect the integrity of said one or more objects (300).

10. Method as in claim 9, characterized in that said method comprises commanding, in an initial step, the switching off of all the sources (15) and the acquisition of said first white light image, and analyzing said first white light image at least in order to detect the presence or absence, in said housing spaces (52), of said one or more objects (300).

11. Method as in claim 9 or 10, characterized in that said method comprises:

- switching off all said sources (15);

- acquiring a second white light image;

- analyzing said second white light image for the identification of the perimeter of said one or more objects (300);

- superimposing the previously identified perimeter on said IR image of the objects (300) illuminated by the sources (15) and limiting the analysis to the area comprised in the perimeter of said one or more objects (300).

12. Method as in any claim from 9 to 11, characterized in that said method comprises:

- switching off all said sources (15);

- acquiring said first white light image and analyzing said first white light image in order to detect the state of cleanliness of said objects (300) and/or the presence of macroscopic defects therein.

13. Method as in any claim from 9 to 12, characterized in that said white light image is an image acquired in conditions in which the objects (300) are illuminated by a white light.