WO2012104218A1

WO2012104218A1 - Detection apparatus and method in the manufacture of low oil potato chips

Info

Publication number: WO2012104218A1
Application number: PCT/EP2012/051348
Authority: WO
Inventors: Oliver HERBERT; Peter David HERRING
Original assignee: Frito-Lay Trading Company Gmbh
Priority date: 2011-01-31
Filing date: 2012-01-27
Publication date: 2012-08-09
Also published as: GB2481470A; GB201101614D0; GB2481470B

Abstract

An apparatus for detecting products on a conveyor, the apparatus comprising a conveyor, an imaging system adapted to image products on the conveyor, a processor coupled to the imaging system, the processor including a converter adapted to convert an image signal from the imaging system to first data representing a first outline of at least one imaged product, a contour device operable on the first data for reducing the first outline to produce second data representing a second outline of at least one central region of the at least one imaged product, the contour device being operable on the second data for increasing the second outline of the or each central region to produce third data representing an estimated third outline of the at least one imaged product.

Description

DETECTION APPARATUS AND METHOD IN THE MANUFACTURE OF LOW OIL POTATO CHIPS

This invention relates to an apparatus and method for detecting products on a conveyor, in particular for controlling the manufacture of snack foods and more particularly the control of the manufacture of potato slices in the manufacture of potato chips, more particularly low oil potato chips which have been cooked by microwave energy.

It has been known for many years to produce potato chips from slices of potato which are fried in oil, usually vegetable oil. Typical conventional potato chips have an oil content of about 30 to 35 wt% oil, based on the total weight of the potato chip. Potato chips exhibit specific organoleptic properties, in combination with visual appearance, to the consumer. The consumer desirous of purchasing a potato chip has a clear expectation of these product attributes in the product.

There is a general desire among snack food manufacturers, consumers and regulatory authorities for healthier food products. In the snack food industry, this has led to a desire for lower fat products. However, even though there may be a general consumer awareness of the benefits of eating lower fat versions of, or alternatives to, existing snack food products, the consumer generally requires the product to have desirable attributes such as texture and flavour. Even if a snack food product is produced which has high nutritional attributes, unless it also has the texture and flavour required by the consumer, the product would not successfully provide the consumer with an acceptable product to replace previous, less healthy snack food products, The challenge among snack food manufacturers is to produce nutritional or more healthy foods which provide the consumer with an improved taste and sensation experience, or at the very least do not compromise on taste and sensation as compared to the consumer's expectation for the particular product or class of products purchased.

There are in the market so-called lower oil snack food products, including potato chips and other products. Some of these processes are produced by modified frying processes using different frying temperatures than those conventionally employed, or cooking processes other than frying, such as baking. Some of these products produce snack foods with low oil, even as low as 5wt%, but the snack food product is not regarded by the consumer to be an acceptable alternative to a potato chip, because the product cannot exhibit the organoleptic properties, in combination with the visual appearance, of a potato chip.

WO-A-2008/01 1489 and WO-A-2009/091674 in the name of Frito-Lay Trading Company GmbH disclose processes for making a healthy snack food. In those processes, a snack food is made so as to have an appearance and taste similar to conventional fried snack products, such as a potato chip. The potato slices are subjected to a sequence of steps which avoids frying of the slices in oil, and the result is a low fat potato chip.

In particular, these specifications disclose the use of microwave cooking of potato slices which have been preconditioned, for example by being treated in oil. Prior to the microwave cooking process, the potato slices are flexible, and have a typical thickness of 1 to 2.5 mm. The microwave cooking rapidly, or explosively, dehydrates the potato slices to achieve low moisture content in a drying step which simulates the conventional frying dehydration rate. It is disclosed that the microwave drying may comprise linear belt or rotary microwave drying. The rapid microwave dehydration rigidifies the cooked potato slices, so that they have a crispness resembling that of typical fried potato chips. Additional final drying steps may be employed, for example using microwave drying.

The potato slices are fed into the microwave cavity on a conveyor, and the input product flow tends to have an uneven or non-uniform slice distribution. Such a distribution results from the original potato feed or from the preceding treatment steps, which may cause the input product flow to come in surges or to be unevenly or non-uniformly distributed across the width of the conveyor. In particular, there may be overlapping or clumping together of potato slices prior to the microwave treatment which explosively dehydrates the potato slices. Such an uneven or non-uniform product distribution for the microwave input changes the amount of product in the conveyor and therefore correspondingly changes the load in the microwave cavity, for example the load changing significantly over a period of less than one minute. The load represents the total amount of water at any given time within the microwave cavity which is energised by the microwave during the microwave treatment of the products within the cavity. Such a variation of the load within the microwave cavity can cause a number of problems, for example uneven drying of the potato slices to form the potato chips, insufficient drying, and/or excess microwave energy within the cavity for the current load, causing arcing.

One particular problem with the manufacture of potato chips from potato slices is that it is difficult to provide a completely uniform flow. Also, the slices vary in shape and dimension, so that the cooked slices exhibit the random three-dimensional shapes of potato chips.

There is therefore a need to control the product flow in the manufacture of snack foods which can in particular be used to control the flow of potato slices in the manufacture of potato chips, more particularly low oil potato chips, prior to a microwave cooking or drying treatment which explosively dehydrates the potato slices. There is accordingly still a need for an apparatus and method for efficiently and reliably manufacturing, in a cost effective manner, a low fat potato chip which has not been fried but has organoleptic properties, in combination with the visual appearance, of a conventional fried potato chip.

The present invention accordingly provides apparatus for detecting products on a conveyor, which products may overlap on the conveyor, the apparatus comprising a conveyor, an imaging system adapted to image products on the conveyor, a processor coupled to the imaging system, the processor including a converter adapted to convert an image signal from the imaging system to first data representing a first outline of at least one imaged product, a contour device operable on the first data for reducing the first outline to produce second data representing at least one second outline of at least one central region of the at least one imaged product, the contour device being operable on the second data for increasing the second outline of the or each central region to produce third data representing an estimated third outline of the at least one imaged product.

The present invention further provides a method for detecting products on a conveyor, which products may overlap on the conveyor, for use in the manufacture of snack foods, the method comprising the steps of:

(a) imaging a plurality of products to form snack food products on a conveyor to produce an image signal of at least one imaged product;

(b) converting the image signal to produce first data representing a first outline of the at least one imaged product; (c) processing the first data to produce second data representing at least one second outline of at least one central region of the at least one imaged product, wherein the first outline is reduced to produce the second outline; and

(d) processing the second data to produce third data representing an estimated third outline of the at least one imaged product, wherein the second outline is increased to produce the third outline.

Preferred features are defined in the dependent claims.

The present inventors have found that the use of a contouring step to estimate a centre of an imaged product and a reverse contouring step to estimate an outline of the imaged product can provide an indication of product overlap which cannot easily be imaged using a direct imaging process. The estimated degree of overlap is indirectly determined from the input image data.

The image data is processed to determine a nominal central region of an imaged product, and then the resultant central region is enlarged around its periphery until at least a portion of a peripheral edge corresponds to the original peripheral edge of the imaged product defined by the image data. This establishes a nominal peripheral edge of the imaged product even if only a portion of the peripheral edge of the imaged product was actually imaged as a result of the product partially overlapping with an adjacent product.

Thus the nominal peripheral edge of each of the overlapping products is determined, and therefore the overlap can correspondingly be determined even though it was not originally imaged. The resultant estimated degree of overlap, or a parameter calculated from the estimated degree of overlap such as mass flow rate, can be used as an input parameter for controlling the manufacturing line. For example, the mass flow rate can be used as an input parameter for controlling a variable such as microwave energy output from a microwave apparatus, or for controlling or informing a packaging machine for packaging products or a bag-filling process.

This can enhance the product quality and/or product uniformity of snack foods, particularly potato chips produced by a microwave dehydration step, such as an explosive dehydration step discussed above, which not only have low oil but also have the combination of flavour, organoleptic properties and shelf life in a non-fried potato chip which is equal or superior in consumer acceptance to conventional fried potato chips.

The invention can also provide a product flow parameter which can increase the efficiency of upstream or downstream operations

An embodiment of the present invention will now be described, by way of example only, with reference to the accompanying drawings in which:

Figure 1 is a schematic perspective view of an apparatus for controlling product flow in the manufacture of snack foods according to an embodiment of the present invention;

Figure 2 is a schematic view of an image produced by an imaging system in the apparatus of Figure 1 ;

Figure 3 is a schematic view of a series of successive shape outlines determined from the image of Figure 2 in accordance with the embodiment of the present invention; and

Figure 4 is a schematic view of final shape outlines determined from the shape outlines of Figure 3 in accordance with the embodiment of the present invention.

An embodiment of an apparatus for controlling product flow, in particular potato slices, prior to microwave cooking of the potato slices to form potato chips, according to one aspect of the present invention is illustrated in Figures 1 to 4.

An endless belt conveyor 2, having a substantially horizontal orientation or being slightly inclined to the horizontal, is provided. An inlet end 4 of the conveyor 2 communicates with an upstream processing station for the potato slices 6. The conveyor 2 carries a succession of the potato slices 6 on its upper surface 8. The conveyor 2 is employed to feed the potato slices 6 to a microwave apparatus 10 for cooking and explosively dehydrating the potato slices 6 in order to produce potato chips, which have not been fried, as for a conventional potato chip. The upper surface 8 of the conveyor 2, for example an endless belt of the conveyor 2, is selected to have a high visual contrast with the products to be conveyed by the conveyor 2. For example, when the conveyor 2 is to be used for conveying potato slices 6, the upper surface 8 may be dark blue in colour.

The potato slices 6 have been randomly delivered onto the conveyor 2 but with a product flow along and across the conveyor 2 so as to provide a substantially constant product flow, but with less than 100 % uniformity and some slice overlap. The potato slices 6 are typically delivered onto the conveyor 2 in a slice distribution so as to have no more than about 50% of the slices overlapping with an adjacent slice, with any such overlap to be no more than about 50% of the slice dimension, and with no more than two slices 6 being stacked one upon the other on the conveyor 2. This substantially provides a monolayer of potato slices 6 across the length and width of the conveyor 2, but with some overlapping and consequential variation of microwave load along and across the conveyor 2.

The potato slices 6 typically have a thickness of 1 to 2.5 mm, more typically about 1.3 mm (51 thousandths of an inch). Since the potato slices 6 are thin and flexible, they are readily able to overlap each other. This means that the flow rate of the potato slices 6 along the manufacturing line, and in particular through specific apparatus in the manufacturing line, such as the microwave apparatus 10, can vary over a short period of time, for example less than one minute, with potential deterioration in product quality and/or uniformity.

As the potato slices 6 are carried on the upper surface of the primary conveyor 2, they are imaged by a camera 12. The camera 12 continuously or continually images the potato slices 6 conveyed thereunder. The field of view of the camera 12 may be applied to all or only a portion of the width of the conveyor 2. The high visual contrast upper surface 8 of the conveyor 2, optionally in combination with overhead illumination of the field of view of the camera 12 by one or more lamps 14, enables the camera 12 readily to be able to image the potato slices 6. However, the overlaps cannot readily be imaged directly because of the low contrast between adjacent or overlapped potato slices 6. The camera 12 is a digital camera which takes individual images successively, or is a video camera which takes a continuous film, of the product flow thereunder. Typically, the imaging system, including the camera 12 and the lamps 14 when present, and including the upper surface 8 of the conveyor 2, are configured to operate using visible radiation, such as white light.

The camera 12 is connected, by a wired or wireless connection 15, to a processor 16 coupled to a display unit 18. The processor 16 has a signal output 20, which may be wired or wireless, and may be transmitted to a control apparatus 22.

The processor 16 is programmed to process the data from the camera 12 representing the imaged products 6 and to determine a parameter indicative of the flow rate of the products imaged by the camera 12.

Each imaged product 6 is analysed in the processor 16 and the processor 16 determines an outline 24 of the imaged product 6. The outline 24 may be approximate, for example a pixellated image 26. The processor 16 includes a converter 17 which converts an image signal from the camera 12 into first data representing a first outline of at least one imaged product. The product may be represented on the display unit 18 as a pixellated image 26, for example as shown in Figure 2. The pixellated image 26 shown in Figure 2 has an outline 28 which suggests that the imaged product is likely to be two products in an overlapping configuration.

The processor 16 then applies an algorithm to the outline 28 which reduces the dimensions of the outline 28 substantially equally around the entire periphery of the outline 28 to produce a first contoured outline 30 shown in Figure 3. For example, for the pixellated image 26, the contoured outline 30 is produced by reducing the outline 28 by one or more pixels around the periphery of the outline 28. The reduction may be applied to reduce the outline for any outer pixel towards an inner pixel which is located along an inner edge of the outer pixel.

This contoured outline 30 is a reduced dimension outline which is similar to providing a contour line on a map. Such a contouring step is carried out iteratively a number of times to produce a series of progressively smaller outlines 32, 34, 36, 38, 40, 42. The different outlines may be displayed as having different respective colours. This contouring is carried out by a contour device 19 in the processor 16 which operates on the first data to reduce the first outline 28 to produce second data representing a second outline 42 of at least one central region 21 of the at least one imaged product.

The number of iterative steps, which may be predetermined, is selected so that, for the particular product dimensions and the contouring dimensions between adjacent outlines 30, 32, 34, 36, 38, 40, 42, the last and smallest outline 42 is statistically likely to indicate the existence of any product overlap. As shown in Figure 3, the smallest outline 42 in fact comprises two such separate and distinct outlines 42a, 42b, each of which is substantially centred on a respective one of two overlapping products. The imaging and processing system has indirectly determined the existence of a product overlap, which could not be directly imaged by the imaging system including the camera 12.

Subsequently, a series of iterative reverse contouring steps is carried out on each of the outlines 42a, 42b. In such a reverse contouring step, an algorithm is applied to the outlines 42a, 42b. The algorithm increases the dimensions of each respective outline 42a, 42b substantially equally around the entire periphery of the outline 42a, 42b, and is thereby used to produce a first enlarged contoured outline as shown in Figure 4. Then the subsequent reverse contouring steps are carried out on each outline 42a, 42b with the same number of reverse contouring steps to produce an enlarged outline as the number of initial contouring steps to produce a reduced outline. By applying the reverse contouring to each of two initial outlines 42a, 42b, the final reverse contouring step provides two overlapped outlines 44, 46, each of which represents an image of a respective estimated overlapped product. Such reverse contouring is carried out by the contour device 19 of the processor 16 which is operable on the second data for increasing the second outline 42a, 42b of the or each central region to produce third data representing an estimated third outline 44, 46 of the at least one imaged product.

The area of each outline 44, 46 can be readily determined, to enable the mass of the corresponding two products to be calculated. Individual products, not in an overlapping configuration, may also readily have their area determined, to enable the respective product mass to be calculated. The use of such an imaging and data processing system enables on-line real-time determination of the flow rate, typically expressed as total mass, of products, such as potato slices 6, passing along the manufacturing line, for example tlirough the microwave apparatus 10. The determined parameter may be employed, in a feed-forward or feedback mode, as an input parameter to control the operation of the manufacturing line, for example to control a variable such as the microwave energy output of a microwave apparatus or a packaging machine for packaging products or a bag-filling line to give an estimate of product characteristics. For example, the signal output 20 of the processor 16 sends a control signal to the control apparatus 22 which in turn sends a control command, by a wired or wirelesss connection 23 to the microwave apparatus 10 which modulates the microwave energy emitted in the microwave cavity dependent upon the immediately upstream product flow imaged by the camera 12. This correlates the microwave energy to the mass flow rate of the products. If desired, a delay may be introduced for a feedforward control.

Alternatively, the control signal may control an upstream operation. For example, if the proportion of overlapping slices is determined to be above a desired threshold, or the degree of overlap or number of slices in any stacked overlap is determined to be above a desired threshold, or the overlap proportion is so low that the product flow rate can be increased without significantly increasing product overlap, the control signal may be employed to modify the product distribution in upstream processing, for example deposition of the products onto the conveyor.

Various modifications to the illustrated embodiment will be readily apparent to those skilled in the art. For example, the imaging system could operate using other than white light, and may use non-visible radiation.

Claims

CLAIMS:

1. An apparatus for detecting products on a conveyor, which products may overlap on the conveyor, the apparatus comprising a conveyor, an imaging system adapted to image products on the conveyor, a processor coupled to the imaging system, the processor including a converter adapted to convert an image signal from the imaging system to first data representing a first outline of at least one imaged product, a contour device operable on the first data for reducing the first outline to produce second data representing at least one second outline of at least one central region of the at least one imaged product, the contour device being operable on the second data for increasing the second outline of the or each central region to produce third data representing an estimated third outline of the at least one imaged product.

2. An apparatus according to claim 1 , wherein the contour device is operable on the first data to produce the second data in a plurality of successive contouring steps, each contouring step producing a respective outline smaller than the preceding contouring step.

3. An apparatus according to claim 2, wherein the contour device is operable so that each respective outline produced in the plurality of successive contouring steps is located inwardly of the preceding outline by a substantially common distance around the circumference of the respective preceding outline.

4. An apparatus according to claim 2 or claim 3, wherein the contour device is adapted to carry out a predetermined number of successive contouring steps.

5. An apparatus according to any foregoing claim, wherein the contour device is operable on the second data to produce the third data in a plurality of successive contouring steps, each contouring step producing a respective outline larger than the preceding contouring step.

6. An apparatus according to claim 5, wherein the contour device is operable so that each respective outline produced in the plurality of successive contouring steps is located outwardly of the preceding outline by a substantially common distance around the circumference of the respective preceding outline.

7. An apparatus according to any foregoing claim, further comprising an image display device adapted to display at least one image related to at least one of the first, second and third data.

8. An apparatus according to claim 7, wherein the processor includes a colour-coding device for colour coding the second data.

9. An apparatus according to claim 8, wherein the contour device is operable on the first data to produce the second data in a plurality of successive contouring steps, each contouring step producing a respective outline smaller than the preceding contouring step, and the colour-coding device is adapted to apply a respective colour to each of the respective smaller outlines.

10. An apparatus according to any foregoing claim, further comprising a control apparatus coupled to the processor and adapted to output a control signal based on the third data.

1 1. An apparatus according to any foregoing claim, which is adapted for controlling the manufacture of snack foods.

12. An apparatus according to any foregoing claim, wherein the imaging system adapted to image potato slices on the conveyor.

13. An apparatus according to any foregoing claim, further comprising a microwave apparatus located for cooking products on the conveyor, wherein the control apparatus is adapted to output the control signal to control the microwave apparatus.

14. A potato chip manufacturing line including the apparatus of claim 13.

15. A method for detecting products on a conveyor which products may overlap on the conveyor, for use in the manufacture of snack foods, the method comprising the steps of: (a) imaging a plurality of products to form snack food products on a conveyor to produce an image signal of at least one imaged product;

(b) converting the image signal to produce first data representing a first outline of the at least one imaged product;

(c) processing the first data to produce second data representing at least one second outline of at least one central region of the at least one imaged product, wherein the first outline is reduced to produce the second outline; and

16. A method according to claim 15, wherein in step (c) the first outline is reduced to produce the second outline in a plurality of successive contouring steps, each contouring step producing a respective outline smaller than the preceding contouring step.

17. A method according to claim 16, wherein in step (c) each respective outline produced in the plurality of successive contouring steps is located inwardly of the preceding outline by a substantially common distance around the circumference of the respective preceding outline.

18. A method according to claim 16 or claim 17, wherein in step (c) a predetermined number of successive contouring steps is carried out.

19. A method according to any one of claims 15 to 18, wherein in step (d) the second outline is increased to produce the third outline in a plurality of successive contouring steps, each contouring step producing a respective outline larger than the preceding contouring step.

20. A method according to claim 19, wherein in step (d) each respective outline produced in the plurality of successive contouring steps is located outwardly of the preceding outline by a substantially common distance around the circumference of the respective preceding outline.

21. A method according to claim 19 or claim 20, wherein in step (d) a predetermined number of successive contouring steps is carried out.

22. A method according to any one of claims 15 to 21 , further comprising step (e) of determining an estimated overlap of imaged products by comparing at least two third outlines produced in step (d).

23. A method according to any one of claims 15 to 22, further comprising the step (g) of displaying at least one image related to at least one of the first, second and third data.

24. A method according to claim 23, comprising the step (h) of colour coding the second data.

25. A method according to claim 24, wherein in step (c) the second data is produced from the first data in a plurality of successive contouring steps, each contouring step producing a respective outline smaller than the preceding contouring step, and in step (h) a respective colour is applied to each of the respective smaller outlines.

26. A method according to any one of claims 15 to 25, further comprising step (f) of outputting a control signal based on the third data.

27. A method according to claim 26, wherein the control signal is employed as an input parameter for an apparatus for manufacturing snack foods.

28. A method according to claim 26 or claim 27, wherein the control signal is representative of a mass flow rate of the products.

29. A method according to claim 26 or claim 27, wherein the control signal is representative of a degree of overlap of the products.

30. A method according to any one of claims 26 to 29, wherein the control signal controls a microwave apparatus located for cooking products on the conveyor.

31. A method according to any one of claims 26 to 29, wherein the control signal controls a packaging machine for packaging products on the conveyor.

32. A method according to any one of claims 15 to 31 , wherein in step (a) the imaged products are potato slices on the conveyor.

33. A method according to claim 32, which is carried out on a potato chip manufacturing line.