WO2018138747A1

WO2018138747A1 - Method and apparatus for counting bars

Info

Publication number: WO2018138747A1
Application number: PCT/IT2018/050012
Authority: WO
Inventors: Gianfranco D'ORLANDO
Original assignee: Alping Italia S.R.L.
Priority date: 2017-01-27
Filing date: 2018-01-26
Publication date: 2018-08-02
Also published as: IT201700009224A1; EP3574471A1

Abstract

A method for counting bars (12) comprising the acquisition of an image (25) corresponding to the ends (15) of a plurality of bars (12) to be counted, and the processing of said image (25) acquired and the calculation of the number of bars (12).

Description

"METHOD AND APPARATUS FOR COUNTING BARS"

FIELD OF THE INVENTION

The present invention concerns a method and an apparatus for counting bars. In particular, the present invention concerns a method and an apparatus which allow to count the bars automatically and with high reliability and precision.

Hereafter in the description, the term "bars" is intended to identify long products, that is, having a main development in the axial direction, and with a round or polygonal section.

BACKGROUND OF THE INVENTION

In the industrial field of the rolling of bars, or steel rods, the products are traditionally sold according to the weight of the material, regardless of the number of products.

However, the tendency to sell the bars based on their actual number is increasingly widespread. This is particularly so in the case of bars made of special materials such as special steels which are particularly expensive.

Apparatuses and methods are known for calculating the number of bars in a bundle starting from the overall weight of the bundle and dividing it by the average weight of a single bar. This solution, however, does not allow a precise counting, especially in the case of bars with a small diameter; in this case, in fact, errors of 4-5% can also be reached in relation to a bundle. These values, if calculated on the basis of annual production volumes, can lead to considerable losses and lack of earnings.

Performing a manual count, although it is a solution, takes a long time and can still be subject to human error.

In order to obtain a reliable count, methods and apparatuses are known which provide to use artificial vision devices, in particular cameras, which acquire images of the bars to be counted and process them to obtain the number of bars. In particular, it is known that at the end of the rolling process the bars are made to pass, substantially parallel to each other, on a bench provided with feed devices, generally chains, which determine the advance of the metal products.

The cameras are disposed in a position axially aligned with the heads of the products collected in bundles. During the acquisition of the images, they also film objects, components of the machine, and everything in the background, and it is therefore necessary to process the images acquired in order to separate the products from the surrounding environment.

One disadvantage of the solutions that use cameras is that a complex processing of the images acquired is required. Furthermore, the quality of the images acquired is often strongly influenced by the conditions of lighting and luminosity of the surrounding environment.

Another disadvantage of the solutions with cameras is the need to provide lighting devices to illuminate the bars in an appropriate manner, with a consequent increase in the overall bulk of the apparatus and in costs.

It should also be considered that the residues of dirt that are generated in the rolling process, or the oxide that is created on the surface of the ends of the bars, reduce the quantity of light reflected by them, so that the cameras cannot detect them correctly.

The bars, moreover, can have deformed ends, for example following the shearing operations, so that they can be difficult to identify. By way of example only, the ends of the bars can be deformed to define "hooks" that the cameras are not able to distinguish, and therefore the final count can be incorrect.

Methods to detect images for counting bars are also known from the publications DA ZHANG et al.: "Bar Section Image Enhancement and Positioning Method in On-Line Steel Bar Counting and Automatic Separating System" and ZHIQUI SU et al.: "Rebar automatically counting on the product line ".

In particular, the first publication describes an on-line bar counting and automatic separating system based on computerized vision. A digital camera is attached near a conveyor in the inspection and separation section, with the purpose of acquiring the image of the bars. The number of bars is then identified by identifying the shapes of the image.

In this system, however, the overall image of all the bars is acquired directly, without processing. Moreover, to optimize image acquisition, a l/1250s lens is used on the camera to avoid blurring of the image due to the movement of the bars.

Furthermore, this publication describes the problem caused by lighting disturbances present in the environment, which condition the optical acquisition of images. To avoid such problems of environmental disturbances for the camera, this known apparatus comprises a screen disposed above the bars to shield the ambient light and generate a dark environment. Moreover, the apparatus is provided with a light source intended to illuminate all the bars with respect to the background and allow direct detection of the image, and a reflector provided to reflect the image of the head of the bars toward the camera. The camera and the light source are disposed in an opposite position with respect to the lying plane defined by the bars.

The camera is also located under the lying plane of the bars and protected by suitable protection systems to prevent the dusty environment from compromising the correct functioning of the camera. This further complicates the management and maintenance of the apparatus.

This known solution is, moreover, particularly complex to make and manage as it requires the presence of screens overlapping moving parts of the plant.

Moreover, this solution does not ensure a correct acquisition of the images, for example when beams of light enter the space comprised between the screen and the plane of moving bars.

One purpose of the present invention is to perfect a method for counting bars or rods which is efficient and guarantees to accurately determine the actual number of bars considered.

Another purpose is to perfect a method that allows to recognize possible deformations of the bars, allowing to distinguish between a bar having a hook or two partly overlapping bars, counting them correctly.

Another purpose of the present invention is to provide an apparatus for counting bars which is simple to make and use, and which can operate with different sizes of the bars to be counted.

Another purpose is to provide an apparatus which does not require particular lighting requirements, thus reducing the overall bulk and complexity.

Another purpose of the present invention is to provide an apparatus able to operate in particularly demanding environments, for example in a steel mill.

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, while the dependent claims describe other characteristics of the invention or variants to the main inventive idea.

In accordance with the above purposes, a method for counting bars comprises:

- the movement of a group of bars on a feed plane and in a direction of feed transverse to the oblong development of the bars

- the acquisition of an image corresponding to the ends of a plurality of bars, - the processing of the image acquired and

- calculating the effective number of bars in the image.

According to one aspect of the present invention, the acquisition of the image provides:

- to emit, with an emitter facing the ends, a laser beam defined by a flat luminous band lying on a lying plane transverse to the feed plane and the direction of feed, in order to hit on each occasion a portion of one of the ends of the bars,

- to move at least one of either the laser beam or the bars with respect to each other, parallel to the direction of feed, so that the laser beam progressively hits all the ends of the group of bars,

- to detect, with a receiver facing the ends, the laser beams reflected on each occasion by the portions of the ends,

- to generate the image on the basis of the laser beams reflected by the ends.

According to another aspect of the present invention, the processing of the image acquired provides to identify in it a plurality of shapes, each corresponding to a respective bar, and to count the shapes identified.

The use of a laser beam as defined above allows to selectively illuminate only a portion of the end of the bar and, by means of a subsequent movement of the laser beam and/or the bars it is possible to illuminate, progressively and in succession, all the portions of the ends of the group of bars, in order to subsequently reconstruct the final image of all the ends of the group of bars. In this way it is possible to concentrate the laser beam on a limited portion of the end of the bars, obtaining an optimized optical detection which is not conditioned by the conditions of the external environment, such as light, shadow zones, dirt, steam or suchlike.

According to some embodiments, the acquisition of the image can provide to move the bars, keeping the laser beam still.

Advantageously the method can provide to acquire the image during the feed of the bars, for example toward a zone where the bundles are formed.

This advantageously allows to position a laser device along any transfer device of the bars, without needing to provide specific zones for counting the bars inside the plant, and without needing particular lighting and environmental conditions.

The laser emitter allows to make the counting of the bars particularly reliable and not influenced by the lighting conditions present. This is also due to the fact that the laser beam has a restricted electromagnetic band, and therefore it is not very sensitive to variations in lighting conditions, and does not need additional lighting.

Moreover, the laser emitter emits a coherent beam of light, that is, with a phase that is constant over time and at high intensity, which allows to correctly recognize and identify even the bars with defective ends or ends covered by residues of dirt or oxide that render them not very reflecting.

Moreover, the use of a laser beam allows to acquire an image that comprises a plurality of areas with a different color from the background, each potentially corresponding to a bar. The different colored areas are due to the ends or portions of the bar which the laser beam hits, and which are found at a reduced and defined distance from the source of emission of the laser beam.

The present invention also concerns an apparatus for counting bars comprising a transfer device configured to transfer a group of bars on a feed plane and in a direction of feed transverse to the oblong development of the bars.

The apparatus also comprises:

- an emitter facing one side of the transfer device in which, during use, ends of the bars are disposed, and suitable to emit a laser beam defined by a flat luminous band lying on a lying plane transverse to the feed plane and the direction of feed, in order to hit on each occasion a portion of one of the ends,

- a movement device configured to move at least one of either the laser beam or the bars with respect to each other, parallel to the direction of feed, so that the laser beam progressively hits all the ends of the group of bars, - a receiver facing the side of the transfer device and configured to detect on each occasion the laser beams reflected by the portions of the ends, and

- at least a processing unit configured to generate the image as a function of the laser beams reflected by the portions of ends, to process the image and to identify therein a plurality of shapes, each corresponding to a respective bar, and to count the shapes.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other characteristics 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 is a perspective view of an apparatus for counting bars according to the invention;

- fig. 2 is a view from above of fig. 1;

- fig. 3 shows an example of an image acquired by the apparatus of fig. 1, - fig. 4 shows an example of an image processed by the apparatus of fig. 1;

- fig. 5 shows an overall block diagram of the counting method according to the invention;

- figs. 6 and 7 show in detail some blocks of the diagram in fig. 5;

- fig. 8 shows in detail some blocks of the diagram in fig. 7;

- fig. 9 shows some possible types of shapes that can be identified in the image acquired.

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 conveniently be incorporated into other embodiments without further clarifications.

DETAILED DESCRIPTION OF SOME EMBODIMENTS

Embodiments described here with reference to figs. 1 and 2 concern an apparatus 10 for counting bars 12.

The apparatus 10 can be used in a rolling plant to count the bars 12, for example before dividing them into batches for storage or sale.

According to some embodiments, the apparatus 10 can comprise a transfer device 14 configured to transfer a group of bars 12 on a feed plane P and in a direction of feed F, transverse to the oblong development of the bars 12. The transfer device 14 can allow to transfer the bars 12 for example from a production zone to a zone in which they are divided into bundles or into batches.

In particular, it can be provided that the transfer device 14 defines the feed plane P on which the bars 12 are positioned and made to advance.

By way of example only, the bars 12 in question can have lengths comprised between 5m and 18m and diameters comprised between about 6mm and 100mm, preferably between about 6mm and 50mm.

The transfer device 14 can comprise at least one of either a conveyor belt, a rollerway, or suchlike.

The bars 12 are generally made to advance parallel to each other, and maintaining their oblong development transverse to the direction of feed F. Moreover, the bars 12 are made to advance while maintaining their respective ends 15, or heads, substantially aligned along a plane orthogonal to the feed plane of the bars 12 and parallel to the direction of feed F defined above.

Here and hereafter in the description, the term "end" 15 refers to the cross- section of the bar 12 located in correspondence with the terminal part of the latter and which is orthogonal to the longitudinal development of the bar 12 itself, that is, corresponding to the surface along the which the bar 12 has been sheared.

The transfer device 14 can be provided with at least one side, or flank, on which the ends 15 of the bars 12 are disposed. In particular, it can be provided that the ends 15 of the bars 12 are positioned protruding cantilevered at least in correspondence with said side or flank of the transfer device 14.

The apparatus 10 comprises a laser device 16 configured to acquire an image 25 relating to the ends 15 of the bars 12.

The apparatus 10 can comprise a processing unit 20 configured to process the image 25.

In particular, the laser device 16 is positioned laterally to the transfer device 14 and facing the ends 15 of the bars 12 to be counted. According to a possible embodiment of the invention, the laser device 16 faces the side or flank of the transfer device 14.

According to some embodiments, the laser device 16 and the bars 12 are mobile with respect to each other.

That is, according to a first solution, for example shown in figs. 1 and 2, the laser device 16 is fixed while the bars 12 are moved in the direction of feed F, for example by the transfer device 14.

According to a second solution, not shown, the bars 12 can be stationary, and the laser device 16 is mobile in a direction parallel to the direction of feed F. According to a third solution, both the bars 12 and the laser device 16 are reciprocally mobile in the direction of feed F. In particular, it can be provided that the bars 12 are mobile in a first sense of the direction of feed F, while the laser device 16 is mobile in the opposite sense, thus increasing the speed of acquisition of the bars 12.

According to some embodiments, the distance of the laser device 16 from the ends 15 of the bars 12, that is, from the side or flank of the transfer device 14, can be varied, for example, depending on the type of the laser device 16, the cross- section of the bars 12, or other factors.

According to some embodiments, the laser device 16 comprises an emitter 17, facing the side or flank of the transfer device 14 where the ends 15 of the bars 12 are disposed during use. The emitter 17 is suitable to emit a laser beam 26 toward the ends 15 of the bars 12.

According to one aspect of the present invention, the emitter 17 is suitable to emit a laser beam 26 defined by a flat luminous band, lying on a lying plane transverse to, advantageously orthogonal to, the feed plane P and the direction of feed F, in order to hit, on each occasion, a portion of one of the ends 15 during movement.

The flat luminous band can have an amplitude which, by way of example only, is comprised between 0.2mm and 2mm. this allows to concentrate the laser beam 26, during use, on a very restricted portion of an end 15 of the bars 12, in order to optimize the subsequent acquisition of the reflection of the laser beam 26.

Using a laser source of this type, unlike a generic or incoherent light source like those described in the state of the art, allows to obtain a high quality image acquisition, irrespective of the lighting conditions of the environment surrounding the bars, such as sunlight, artificial light, dust, steam or suchlike.

According to another solution, the flat luminous band has a development that diverges from the emitter 17 toward the end of the bars 12.

According to possible solutions, the angle of divergence of the laser beam 26 is comprised between 40° and 70°.

According to one aspect of the present invention, the apparatus 10 comprises a movement device configured to move at least one of either the emitter 17 or the bars 12 with respect to each other, parallel to the direction of feed F, so that the laser beam 26, during movement, progressively hits all the ends 15 of the group of bars 12.

According to a possible solution, the movement device is defined by the transfer device 14 which provides to move the bars 12 with respect to the emitter 17.

According to a possible variant embodiment, not shown, the movement device can be associated with the emitter 17 in order to move it with respect to the bars 12.

According to some embodiments, the laser device 16 comprises a receiver 18, configured to receive a reflected laser beam 27 from the ends 15. In particular, the receiver 18 is located facing the side or flank of the transfer device 14 and is configured to detect, on each occasion, the laser beams 27 reflected by the portions of the ends 15.

In particular, the emitter 17 and the receiver 18 are disposed facing the same side or flank of the transfer device 14.

According to possible solutions, the receiver 18 comprises a camera suitable to detect the reflected laser beam 27.

According to possible solutions, the receiver 18 comprises optical devices such as filters, lenses or suchlike, configured to selectively detect only the reflected laser beam 27. This allows to obtain a portion of image in which the portion of end 15 hit by the laser beam 26 is suitably enhanced, while everything that is around it is obscured.

According to some embodiments, the emitter 17 and the receiver 18 are located at a defined distance from one another in a direction parallel to the direction of feed F, thus being able to implement a triangulation method to generate the image 25 of the ends 15 of the bars 12 to be counted. With the triangulation method it is possible to eliminate all the problems of known solutions due to the environment, such as light, dark, dirt or suchlike, and ordinary and extraordinary maintenance operations are reduced. According to a possible aspect of the present invention, both the emitter 17 and the receiver 18 are installed in a fixed position and facing the side or flank of the transfer device 14.

According to a possible solution, the emitter 17 and the receiver 18 are located on a plane substantially parallel to the feed plane P.

In particular, the emitter 17 and the receiver 18 are positioned with respect to each other so that the receiver 18 receives the reflected laser beam 27 only from the part of the bars 12 which are nearest the laser device 16, or the ends 15. In fact, portions of the bars 12 which are located farthest from the ends 15, even though they generate the reflection of a reflected laser beam 27, are not detected because the latter does not affect the receiver 18.

The reciprocal positioning of the emitter 17 and the receiver 18 also allows to define an overall working field of the laser device 16 and if necessary, by means of suitable processing, it is possible to delimit this working field to a single portion. The working field is usually defined by a minimum distance and a maximum distance, from the ends 15 of the bars 12, for which the laser beam 27 reflected by the object is picked up by the receiver 18.

By way of example only, in a working field comprised between 10cm and 40cm it is possible to exclude from the formation of the image 25 any object located outside the range comprised between 15cm and 18cm, taking advantage of the information on the distance of the points from the receiver 18.

This means that, despite the fact that the reflected laser beam 25 of an object located, for example, at 8cm affects the detector 18 (therefore it is actually physically detected), it is excluded from the formation of the image 25 if it does not belong to the portion of working field defined.

Processing of the working field can be performed by the processing unit 20.

In accordance with possible solutions, the laser beam 26 is emitted in a direction substantially parallel to the oblong development of the bars 12 and is thus able to directly affect a limited portion, determined by the flat luminous band, of one of the head ends 15 of the bars 12.

In particular, it is provided that the laser beam 26 emitted is incident against the head surface of the ends 15 of the bars 12, that is, the emitter 17 is configured to emit a laser beam 26 which is located transversely to the direction of feed F and is incident to a plane orthogonal to the lying plane of the bars 12 and on which the direction of feed F lies.

In accordance with some embodiments, the emitter 17 can emit a laser beam 26 having a narrow electromagnetic band, and concentrated in the neighborhood of a specific wavelength. For example, the electromagnetic band can be concentrated around the wavelength of red, that is, comprised between about 620 and 680 nm, or green, that is, between about 515 and 565 nm.

According to some embodiments, the emitter 17 is configured to emit a laser beam 26 lying on a plane transverse to, in this specific case orthogonal to the plane of feed of the bars 12 and to their direction of feed F.

The use of a laser beam with a flat and non-punctiform emission, combined with a relative motion of the bars 12 and the transfer device 14, allows to obtain a scan of the bars 12, and in particular of their ends 15.

According to a possible solution, the combination of the emission of the laser beam 26, the reciprocal movement of at least one of either the laser beam 26 or the bars 12, and the detection of the reflected laser beams 27 defines a progressive scan of all the ends 15 of the group of bars 12 in order to generate said image 25.

The laser device 16 can be provided with a processing unit configured to detect the signals of the reflected laser beam, process them and generate the image 25.

According to possible solutions, the processing unit of the laser device 16 can be separate and independent of the processing unit 20 defined above.

However, it is not excluded that in possible variant embodiments the processing unit 20 is able to process the image 25 and also to process the image itself for the subsequent counting of the bars 12.

The reflected laser beams 27, in fact, constitute the image 25 defined by a plurality of shapes S having colors different from the background K, and corresponding to the ends 15 of the bars 12 to be counted.

In particular, the processing unit 20 can be configured to generate the image 25 depending on the laser beams 27 reflected by the portions of ends 15, to process the image 25 and to identify therein a plurality of shapes S, each corresponding to a respective bar 12, and to count the shapes S. The shapes S of the image 25 can have color gradations that identify portions of the end 15 which are more or less close to the laser device 16.

For example, in the case of cusp-shaped ends 15, the shapes of the image 25 can have zones with a lighter color shade which identify zones of the end of the bar 12 nearest to the laser device 16, while zones with a darker shade identify zones farthest away from the ends 15.

By way of example only, it can be provided that the image 25 is defined by grayscale colors in which the lighter gray identifies a part of bar 12 very close to the laser device 16, while the farthest part is identified by darker colorations of gray.

According to possible variant embodiments, however, it is not excluded that the processing unit 20 is configured to process an image 25 in which the darker color shade identifies zones of the end of the bar 12 closest to the laser device 16, while the lighter color shade identifies zones of the end of the bar 12 farthest away from the laser device 16.

The processing unit 20 is connected to the laser device 16 and is configured to process the image 25 acquired by the latter.

According to some embodiments, the processing unit 20 can receive from the receiver 18 information relating to the reflected laser beams 27 and can generate the image 25 of the ends 15 of the bars 12 scanned.

According to some embodiments, the processing unit 20 can generate the image 25 at the end of the scanning of all the bars 12 of a group. In this way the apparatus 10 is independent of the transfer devices 14 and no sensors are required, or encoders to synchronize the relative movement of the laser device 16 and the bars 12.

According to possible solutions, the image 25 can be generated directly in real time during the reciprocal movement of the bars 12 and the laser device 16.

The apparatus 10 can also comprise a user interface 22, connected to, or integrated in the processing unit 20, by means of which a user can set the operating parameters of the apparatus 10.

The user interface 22 can allow a user to insert into the processing unit 20 parameters relating to at least the shape and sizes of the cross-section of the bars 12 to be counted. In accordance with other embodiments, the user interface 22 allows to introduce parameters relating to the feed of the bars 12.

In accordance with possible solutions, the processing unit 20 can be connected to the transfer device 14 to receive from the latter information relating to the modes of feed of the bars 12, or to receive information relating to the speed of feed and/or to a stoppage of the feed of the bars 12.

In particular, it can be provided that the processing unit 20 receives from the transfer device 14 at least the information regarding the stoppage of the bars 12 to allow a reduction of the errors in counting the bars 12.

According to possible variant embodiments, it can be provided that, on the basis of the information detected from the image 25, the processing unit 20 is able to identify conditions in which there is a stoppage in the movement of the bars 12. For example, if there is no reciprocal movement of the laser device 16 and the ends of the bars 12, the image 25 processed can show a continuous band along its longitudinal extension.

The apparatus 10 can also comprise a memorization device 23, connected to or integrated with the processing unit 20, in which the parameters set using the user interface 22 and/or the information relating to the feed of the bars 12 can be memorized.

According to some embodiments, the apparatus 10 can comprise a display device 24, connected to the processing unit 20, to display to a user the number of bars 12 counted, and possibly the image 25 of the ends 15 of the bars 12.

In accordance with other embodiments, described for example with reference to fig. 2, downstream of the laser device 16, the apparatus 10 can comprise a video camera 30, or other image acquisition device, suitable to acquire in real time an image of the bars 12 during their feed.

The video camera 30 can be connected at least to the processing unit 20 and possibly to the laser device 16. In accordance with these embodiments, the video camera 30 can acquire images of the advancing bars 12, and the processing unit 20, possibly processing said images, can identify the defective bars 12 among them, in order to separate them from the others.

For example, according to possible embodiments, the video camera 30 can be connected to a removal member, not shown, able to remove the bar 12 recognized as defective from the subsequent bars 12.

The apparatus 10 as a whole has small and compact sizes, so that it can be positioned both on fixed supports, as shown, for example, in figs. 1 and 2, and also on mobile supports, for example rods, disposed in different zones according to the type of bars 12 and the suitable acquisition position.

The present invention also concerns a method for counting bars 12, of which fig. 5 shows a block diagram by way of example.

The method according to the invention comprises the acquisition of the image 25 relating to the ends 15 of the bars 12 to be counted, and the processing of the image 25 acquired.

According to one embodiment, the acquisition of the image 25 provides to emit a laser beam 26 toward the ends 15 of the bars 12 and to receive a reflected laser beam 27 from them.

The acquisition of the image 25 also comprises the relative movement of the laser device 16 and the bars 12.

The processing of the image 25 comprises the identification, in the image 25 itself, of a plurality of shapes S, each corresponding to the end 15 of a bar 12.

According to some embodiments of the present invention, in order to identify the shapes S, the method provides to generate a virtual model M corresponding to the ideal shape of an end 15 of a bar 12. The model M is determined as a function of the geometric sizes of the bar 12, as a function of the relative speed of movement of the laser device 16 and the bars 12, and possibly other factors.

In accordance with possible embodiments, the method according to the present invention can comprise the identification in the image 25 of the shapes S by comparing the virtual model M generated and different portions of the image 25 itself. If there is a correspondence between the portion of the image 25 analyzed and the virtual model M, a shape S of the bar 12 is recognized.

The comparison between the portions of the image 25 and the virtual model M can comprise the overlapping of the virtual model M, on each occasion, over a different portion of the image 25, and the calculation of a coincidence index between the virtual model M and the portion of the image 25.

If the coincidence index is higher than a certain threshold, the shape S of one of the bars 12 is identified in the image 25. The calculation of the coincidence index can provide a comparison between the colors of the virtual model M and those of the portion of image 25 which is analyzed on each occasion.

By way of example only, this comparison can provide a comparison between the grayscale gradients present in the portions of image 25 which are analyzed on each occasion and the grayscale of the previously generated virtual model M.

According to some embodiments, at the end of the comparison between the virtual model M and the image 25, the method can provide to count the shapes S identified, obtaining a provisional count, and possibly to put the shapes S in order.

Once the whole image 25 has been analyzed, and therefore the shapes S have been identified, the method can comprise an analysis of the shapes S identified in the image 25 to determine if there are overlapping and/or adjacent shapes S.

By way of example only, fig. 9 shows possible cases of adjacent shapes S, in which, for example, in figs. 9a and 9b the shapes S are adjacent but not overlapping each other, in fig. 9c two shapes substantially overlap each other, providing a false count, and in fig. 9d two shapes are partly overlapping.

In accordance with possible embodiments, the method can comprise the determination of a distance D between the centers of pairs of shapes S identified, and the comparison of the distance D with a reference distance determined, in turn, according to the sizes of the cross section of the bars 12 and the reciprocal movement of the laser beam 26 and the bars 12. According to possible solutions, the reference distance can be determined according to the virtual model M generated above, that is, at least according to the sizes of the cross section of the bar 12 and the speed of feed.

If the distance D is greater than the reference distance, the two shapes S 1 and S2 identified are independent of each other and therefore identify two separate bars 12.

If the distance D between the two shapes S 1 and S2 is less than the reference distance, the method comprises the generation of contours C of the pair of shapes S 1 and S2, the calculation of a minimum distance DMIN between the contours C of the pair of shapes S I and S2 and the comparison of the minimum distance DMIN with a minimum reference distance. If the minimum distance DMIN is greater than the minimum reference distance, then the two shapes S I and S2 are recognized as identifying two bars 12 that are separate from each other; if the minimum distance DMIN is smaller, a further processing of the shapes S 1 and S2 is provided.

This further processing of the shapes S 1 and S2 can comprise the generation of a shapes envelope IS which surrounds and encloses inside it the shapes S 1 and S2.

The method also provides to determine one or more residue areas AR determined by the difference between the area of the shapes envelope IS and the areas of the shapes S I and S2 considered.

The method then provides to compare the residue areas AR with a previously set reference residue area. If the residue areas AR are greater than the reference residue area, the two shapes S I and S2 are recognized as identifying two bars 12 that are separate from each other; on the contrary, if they are smaller, the residue areas AR are processed.

The processing of the residue areas AR can comprise the generation of an areas envelope IA that surrounds and encloses the residue areas AR inside it.

The method then provides to determine differential areas AD calculated as the difference between the areas of the shapes S 1 and S2 considered and the areas envelope IA.

If the number of differential areas AD is greater than one, the shapes S 1 and S2 each identify a respective bar 12. If the number of the differential areas AD is equal to one, the two shapes S I and S2 identify a single bar 12, which is therefore counted by the processing unit 20.

At the end of the processing, the method can provide to make the final count available, and possibly to display the correspondences found, for example on the display device 24.

According to other embodiments, once the display of the correspondences is obtained, it is possible to use the video camera 30, located downstream of the apparatus 10 and communicating with it, to mark or signal particular bars 12.

It is clear that modifications and/or additions of parts can be made to the apparatus 10 and method for counting bars 12 as described heretofore, without departing from the field and scope of the present invention. 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 apparatus 10 and method for counting bars 12, having the characteristics as set forth in the claims and hence all coming within the field of protection defined thereby.

Claims

1. Method for counting bars (12) comprising the movement of a group of bars (12) on a feed plane (P) and in a direction of feed (F) transverse to the oblong development of said bars (12), the acquisition of an image (25) corresponding to the ends (15) of a plurality of bars (12) to be counted, the processing of said image (25) acquired and the calculation of the number of bars (12), characterized in that said acquisition provides:

- to emit, with an emitter (17) facing said ends (15), a laser beam (26) defined by a flat luminous band lying on a lying plane transverse to said feed plane (P) and said direction of feed (F), in order to hit on each occasion a portion of one of said ends (15) of said bars (12),

- to move at least one of either said laser beam (26) or said bars (12) with respect to each other, parallel to said direction of feed (F), so that said laser beam (26) progressively hits all the ends (15) of said group of bars (12),

- to detect, with a receiver (18) facing said ends (15), the laser beams (27) reflected on each occasion by said portions of said ends (15),

- to generate said image (25) on the basis of said laser beams (27) reflected by said ends (15),

and in that said processing provides to identify, in said image (25), a plurality of shapes (S) each corresponding to a respective bar (12) and to count said shapes (S).

2. Method as in claim 1, characterized in that the combination of the emission of said laser beam (26), the reciprocal movement of at least one of either said laser beam (26) or said bars (12), and the detection of said reflected laser beams (27) defines a progressive scan of all the ends (15) of said group of bars (12) in order to generate said image (25).

3. Method as in claim 1 or 2, characterized in that said flat luminous band has an amplitude comprised between 0.2mm and 2mm.

4. Method as in claim 1, 2 or 3, characterized in that the identification of the shapes (S) in the image (25) provides to generate a virtual model (M) determined as a function at least of the geometric sizes of the bar (12) and the relative movement of the laser device (16) and the bars (12).

5. Method as in claim 4, characterized in that in order to identify the shapes (S) in said image (25) it provides to compare the virtual model (M) generated and different portions of the image (25), and to calculate a coincidence index between the virtual model (M) generated and the portion of the image (25).

6. Method as in any claim hereinbefore, characterized in that it comprises an analysis of the shapes (S) identified in the image (25) to determine if there are overlapping and/or adjacent shapes (S).

7. Method as in claim 6, characterized in that the analysis of said overlapping and/or adjacent shapes (S) comprises determining a distance (D) between the centers of pairs of shapes (S) identified, and comparing the distance (D) with a reference distance in its turn determined on the basis of the sizes of the cross section of said bars (12) and the reciprocal movement of said laser beam (26) and said bars (12).

8. Method as in claim 7, characterized in that the analysis of said adjacent shapes (S) comprises generating contours (C) of a pair of adjacent shapes (S I, S2), calculating a minimum distance (DMIN) between the contours (C) of the pairs of shapes (S I, S2) and comparing the minimum distance (DMIN) with a reference minimum distance, and if the minimum distance (DMIN) is greater than said reference minimum distance, said shapes (S I, S2) are recognized as identifying two bars (12).

9. Method as in claim 8, characterized in that the analysis of said adjacent shapes (S) comprises:

- generating a shapes envelope (IS) that surrounds and encloses inside it a pair of said shapes (S I, S2),

- determining one or more residue areas (AR) determined by the difference between the area of the shapes envelope (IS) and the areas of the shapes (S I, S2) considered,

- comparing the residue areas (AR) with a set reference residue area, and if said residue areas (AR) are greater than the reference residue area, said shapes (S I, S2) are recognized as identifying two bars (12).

10. Method as in claim 9, characterized in that it comprises generating an areas envelope (IA) that surrounds and encloses inside it the residue area or areas (AR), determining differential areas (AD) calculated as the difference between the areas of the shapes (S I, S2) considered and the areas envelope (IA), and if the number of the differentiated areas (AD) is greater than one, said shapes (S I, S2) each identify a respective bar (12), and if the number of differentiated areas (AD) is equal to one, the shapes (S I, S2) identify a single bar (12).

11. Apparatus for counting bars (12), comprising a transfer device (14) configured to transfer a group of bars (12) on a feed plane (P) and in a direction of feed (F) transverse to the oblong development of said bars (12), characterized in that it comprises:

- an emitter (17) facing one side of said transfer device (14) in which, during use, ends (15) of said bars (12) are disposed, and suitable to emit a laser beam (26) defined by a flat luminous band lying on a lying plane transverse to said feed plane (P) and said direction of feed (F), in order to hit on each occasion a portion of one of said ends (15),

- a movement device configured to move at least one of either said laser beam (26) or said bars (12) with respect to each other, parallel to said direction of feed (F), so that said laser beam (26) progressively hits all the ends (15) of said group of bars (12),

- a receiver (18) facing said side of said transfer device (14) and configured to detect on each occasion the laser beams (27) reflected by said portions of said ends (15), and

- at least a processing unit (20) configured to generate the image (25) as a function of said laser beams (27) reflected by said portions of ends (15), to process said image (25) and to identify therein a plurality of shapes (S), each corresponding to a respective bar (12), and to count said shapes (S).