SYSTEM AND METHOD FOR AUTOMATIC REMOVAL OF

FOREIGN OBJECTS FROM A FOOD SURFACE

TECHNICAL FIELD

This invention relates to a system and a method for automatic removal of foreign objects from the surface of food products. The system of the invention comprises a machine vision device and an industrial robot, which robot is equipped with one or more removal tools.

BACKGROUND ART

The risk of having foreign objects in food products is great concern to the food industry, and efforts have been made for removal of undesirable material from food products, to increase food safety and food quality.

One approach to the removal of undesirable material from workpieces involves the use of a suction device.

Thus WO 2003/026432 A1 and WO 2009/138083 A1 disclose devices for cleaning the surface of carcass parts by the combined use of suction and steam treatment, and EP 1275304 Al, DK 177163 Bl, and WO 2018-172214 A1 disclose tools for removing tissue parts from the surface of carcass parts that works without steaming the meat surface.

A different approach to finding foreign objects on the surface of food products involves the use of scanning/vision techniques.

Thus DK 177214 Bl and WO 2017/121713 describe certain scanning/vision equipment, using a combination of spectral ranges within vision, NIR and X-rays, and useful for finding foreign objects in food products.

US 4970757 relates to automated excision of undesirable material from meat, which method includes an apparatus for optical detection of the location of undesirable material in meat, a sonar scanner, and a multiple blade slicer, i .e. a high-pressure water jet.

WO 2002/43502 describes a method for detecting and removing undesirable material from workpieces using an X-ray vision device and a cutter for excision of an entire part of the food product.

WO 2008/102143 relates to a method and a device for sensing foreign bodies in e.g . food products, which arrangement has a first and a second light source and an imaging device, and the light sources have different wavelengths. WO 2013/023778 describes a meat inspection system, comprising supply means, a radiation inspection facility, e.g . an X-ray inspection device, a cutting facility, and a reject facility.

WO 2015/198062 relates to a method and apparatus for removing foreign objects from food pieces, wherein the detecting step comprises an X-ray analysis to determine the coordinates of the foreign object.

WO 2017/048783 describes a system and a method for detecting foreign objects using a multi-spectral vision device for colour analysis.

However, the use of a multi-spectral vision device, capable of identifying light density foreign objects, and robot technology for targeted removal of foreign objects has not been described.

SUMMARY OF THE INVENTION The system of the invention enables an automatic process and represents an attractive alternative to conventional manual surveillance for foreign objects in food products.

The system of the invention and related process makes use of various light panels and multi-spectral visions devices to create images composed of many line scans, which makes the final image dynamic, and relative to the object to be measured.

The removal tools for use according to the invention removes only minimal amounts of food product, thereby giving less waste, and when used according to the invention, the removal tool is not in constant contact with the food product, which minimises the risk for dissemination of microorganisms.

Therefore, in its first aspect, the present invention provides a system for removing foreign objects from a food surface, while the food product is in motion, which system may be characterised as described in the claims.

In another aspect, the present invention provides a method for removing foreign objects from a food surface, while the food product is in motion, which method may be characterised as described in the claims.

Other objects of the invention will be apparent to the person skilled in the art from reading the following detailed description and accompanying drawings.

Any combination of two or more of the embodiments described herein is considered within the scope of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

The present invention is further illustrated by reference to the accompanying drawing, in which:

Fig. 1 shows an overview of the components comprised within the system of the invention (1) : Inlet conveyor (2); Machine vision device (3); Industrial robot (4); Foreign object removal tool (5); Processing means/controller (6); 3D scanning device (7);

Fig. 2 shows a draghead device (5A) for use according to the invention;

Fig. 3 shows a gripping tool (5B) for use according to the invention; and Fig. 4 shows a cutting tool (5C) for use according to the invention.

DETAILED DISCLOSURE OF THE INVENTION

The system of the invention

In its first aspect, the invention provides an automatic system for targeted removal of foreign objects (1) from the surface of a food product (8), while the food product is being transported on a conveyor.

By performing a targeted (i.e. object focused) removal of undesired foreign objects, less waste is produced.

The system may be applied to any food product arriving on a conveyor belt, but food products contemplated according to this invention are in particular meat products of any animal origin, including meat trimmings and cuts, and processing's hereof, e.g. grindings.

The system of the invention may be characterised by comprising :

an inlet conveyor (2);

one or more multi-spectral machine vision devices (3) ;

one or more industrial robots (4);

a foreign object removal tool (5); and

a processing means/controller (6) .

Optionally, the system of the invention also comprises a 3D scanning device

(7) .

The in-let conveyor

The in-let conveyor belt (2) for use according to the invention shall supply the food products (8) to be analysed. It should be intended that the food products arrive evenly distributed on the conveyor belt, so that the surface of the products is available for the subsequent inspection. For the processing means (6) to be able to calculate and track the position of the incoming food product (8) while in motion, and keep the projection means (6) synchronized with the conveyor belt (2), the system shall know the speed of the conveyor belt (2) . This may be accomplished in various ways.

The in-let conveyor belt (2) for use according to the invention may be equipped with an encoder, in communication with, and receiving operational guidance from, the processing means (6). This ensures that the system can performing certain functions, like controlling (determine and adjust) the speed of the conveyor belt and synchronize with the robot (4) .

There are four widely used methods of applying encoders to conveyors: motor mount, roller shaft mount, belt/chain driven and surface mount. Any type of encoder may be employed according to the invention .

The machine vision device

The multi-spectral machine vision device (3) for use according to the invention shall analyse the surface of the incoming food products (8) while they are being transported on the conveyor belt (2) and shall transmit the digitalized data to the processing means (6) . For fulfilling this task, the vision device (3) shall be in

communication with the processing means/controller (6) .

A multi-spectral image is one that captures image data within specific wavelength ranges across the electromagnetic spectrum . The wavelengths may be separated by filters or by the use of instruments that are sensitive to particular wavelengths, including light from frequencies beyond the visible light range, i .e. infrared and ultra-violet. Spectral imaging can allow extraction of additional information the human eye fails to capture with its receptors for red, green and blue.

Multi-spectral imaging measures light in a small number (typically 3 to 15) of spectral bands.

Multi-spectral imaging can also be accomplished by using camera(s) sensitive to all the relevant spectral bands and sequentially illuminating the object with each spectral band, while capturing a frame for each band.

The vision device (3) for use according to the invention may be any

commercially available machine vision system . Machine vision systems essentially comes in three main categories:

ID vision analyzes a digital signal one line at a time instead of looking at a whole picture at once, and is accomplished by use of a line-scanner;

2D vision is looking at the whole picture, and may be accomplished by use of an industrial camera; and 3D vision systems typically comprise multiple cameras or one or more laser displacement sensors.

In one embodiment, the vision device for use according to this invention is a ID vision device, i.e. a line scan camera.

In another embodiment, the vision device for use according to the invention comprises a light source capable of emitting electromagnetic waves in the ranges 350nm to 700nm (UV-visible region) and/or 700nm to 950nm (i .e. NIR), and a sensor capable of receiving electromagnetic waves within the same ranges (i .e. 350nm to 950nm), and may e.g. a device as described in e.g . WO 2017/121713.

Optionally, the system of the invention comprises a 3D scanning device (7) .

In case the incoming food product (8) to be scanned can be considered arriving in the form of a in two-dimensional distribution only (e.g. greaves from pork, lying flat on the conveyor belt), a regular vision device (3) may be considered sufficient for the identification and location of any foreign object to be removed . However, if the incoming food product (8) is considered represented by a spatial distribution (e.g . pork back, pork belly, or beef striploin), the vision device should be supplemented with a 3D scanning device (7), to determine the height and calculate angle of the food surface, thus allowing optimal guidance of the robotic arm to position the working tool (5) in the right angle.

The vision device (3), in a combination with the 3D scanning device (7), may determine which tool (5) to use in each situation, i .e. whether to use suction only (5A), grabbing only (5B), or cutting only (5C), or whether a combination of two or more of these tools should be used . This may be decided based on the nature of the incoming food product (8), the nature of the foreign object to be removed, and/or based on the exact position of the foreign object to be removed. If, based on vision analysis, it is found that the foreign object in question is a light density object (e.g . plastic or similar foreign object), removal by suction only may be justified. If, on the other hand, the foreign object to be removed is found to be a difficult accessible object (e.g. cartilage or bone fragments), removal by gripping or cutting may be considered. In other cases, a combination of two or more removal tools may be selected, as determined by the vision device (3) in communication with the controller (6) .

The 3D scanning devices (7) for use according to the invention may be any commercially available 3D scanner or range camera, such as a time-of-flight camera, structure light camera, stereo camera or 3D camera, e.g. a Sick 3D ruler.

The industrial robot

The system of the invention comprises one or more industrial robots (4), each robot equipped with, and capable of operating the foreign object removal tool (5). For performing its tasks, each robot shall be in communication with, and receive operational guidance from, the processing means (6).

The system of the invention may accomplish its task by using only one industrial robot (4), mounted with a multi-functional working tool (5), or by using two or more industrial robots (4), each robot mounted with a mono-functional working tool (5A, 5B), or, alternatively, with a multi-functional working tool (5).

In one embodiment, the system of the invention comprises only one industrial robot (4), holding a foreign object removal tool (5).

In another embodiment, the system of the invention comprises two or more industrial robots (4), each robot holding a foreign object removal tool (5).

The robot for use according to the invention may be any commercially available industrial robot. Industrial robots may be classified based on their coordinate systems, i.e. based on reachable coordinates of a point on the end-effector, and include Cartesian robots (when arms of a robot move in the XYZ rectangular coordinate system),

Cylindrical robots (when arms of a robot move in one angular and two linear directions), Spherical robots (the arms move in two angular and one linear direction), SCARA robots (Selective Compliance Arm for Robotic Assembly; have two parallel revolute joints providing compliance in a selected plane), and Articulated robots (also known as the anthropomorphic robot, the robot arm has 3 revolute joints).

The foreign object removal tool

For performing the task of removing foreign objects from the surface of food products (8), the robot(s) (4) for use according to the invention shall be equipped with the necessary working tool, i.e. a foreign object removal tool (5). The foreign object removal tool (5) is a tool capable of taking away foreign objects located on the surface of the transported food product (8).

In one embodiment, the foreign object removal tool (5) is a multi-functional working tool (5X).

In another embodiment, the foreign object removal tool (5) is a draghead device (5A). A draghead device for use according to the invention may be any suction head that can be mounted on an industrial robot. Moreover, the draghead device shall be connected to a vacuum generator (5A'), so that the foreign object can be effectively removed from the surface of the food product.

Different types of suction heads have been described in e.g. EP 1275304 Al, DK 177163 Bl, and WO 2018-172214 Al, mentioned above, and they may be all be used in the system of this invention.

In a third embodiment, the foreign object removal tool (5) for use according to the invention is a gripping tool (5B). In a fourth embodiment, the foreign object removal tool (5) for use according to the invention is a cutting tool (5C) .

Gripping and cutting can be done in more ways, e.g. by pinching for removal of a volume of meat by gripping the meat with a pinch/grip knife, or by planning for removal of an area of the surface using a planning knife, and the area being processed may in addition be vacuum cleaned/sucked to dispose of the foreign objects.

The different foreign object removal tools (5) contemplated for use according to this invention may be applied under different circumstances:

in some cases, the identified foreign object is removed only by use of the suction device (5A), assisted by the vacuum generator (5A') ;

in other cases, the identified foreign object is removed only by use of the gripping tool (5B) only; and

in yet other cases, the identified foreign object is removed only by use of the cutting tool (5C) only.

The foreign object removal tools (5) in question may be introduced by use of one or more robots (4) . One tool (5), whether a draghead device, a gripping tool or a cutting tool, may be mounted on one robot (4), and two or more robots (4) may work together to solve the task. Or all tools (5A, 5B and 5C) may be available on one robot (4) in the form of a multi-tool (5X) mounted on the robot (5), which robot (4) is configured for operating the multi-tool (5X), and able to switch between any of those tools (5A, 5B and/or 5C) attached to the robot (4) .

The processing means/controller

The processing means/controller (6) for use according to the invention may be any commercially available controller or processor. The processor/controller for use according to the invention shall be in operation with, and provide instructions to

the rotary encoder controlling the inlet conveyor (2) ;

the machine vision device (3) ; and

the one or more industrial robots (5) ; and, optionally,

the 3D scanning device (7) .

The processor/controller for use according to the invention shall be configured for:

controlling (determining and adjusting) the speed of the inlet conveyor (2), to keep it synchronized with the rest of the system;

analysing the digitalised data received from the vision device (3), and/or the 3D scanning device (7), and determining the position of any foreign objects located on the food product (8) ; and instructing the robot (4) holding the removal tool (5) to move the draghead tool and bring it into position for removal of the foreign object, while the food product (8) is in motion.

In case the incoming food product (8) to be scanned can be considered arriving in a in two-dimensional distribution only (e.g. greaves from pork, lying flat on the conveyor belt), a regular vision device (3) may be considered sufficient for the identification and location of any foreign object to be removed. However, if the incoming food product (8) is considered represented by a spatial distribution (e.g. neck of pork, pork belly, beef sirloin, etc.), the vision device should be supplemented with a 3D scanning device (7).

Examples of commercially available controllers include fast industrial PC's equipped with imaging graphic modules.

The method of the invention

In another aspect, the invention provides a method for automatic, targeted removal of foreign objects from the surface of a food product (8), while the food product is conveyed. The method of the invention may be characterised by, and comprising the subsequent steps of:

(a) providing the food product (8) to be analysed, evenly distributed on a conveyor belt (2);

(bl) scanning the incoming food products (8), while in motion, using a multi- spectral machine vision device (3);

(c) processing the obtained images in a processing means (6), and determining the position of any foreign object located the surface of the food product (8); and

(d) subjecting the food product to removal by use of a removal tool (5), mounted on an industrial robot (4), which robot (4) is in operation with and receiving guidance from the processing means (6).

In another embodiment, the method of the invention comprises:

(b2) scanning the incoming food products (8), while in motion, using a multi- spectral vision device (3), supplemented with the use of a 3D scanning device (7).

In a further embodiment, the method of the invention may be accomplished using the system for automatic, targeted removal of foreign objects (1) of the invention.

List of reference signs

In the figures, identical structures, elements or parts that appear in more than one figure are generally labelled with the same numeral in all the figures in which they appear.

1. The system of the invention; 2. Inlet conveyor;

3. Machine vision device;

4. Industrial robot;

5. Foreign object removal tool; 5X. Multi-functional tool;

5A. Draghead device;

5A'. Vacuum generator;

5B. Gripping tool;

5C. Cutting tool;

6. Processing means/ controller;

7. 3D scanning device;

8. Food product;