WASTE SEPARATION METHOD

Abstract

A method of waste separation includes irradiating the waste by a source of radiation, capturing an image of the waste when irradiated by the source of radiation; where an item in the waste is provided with a pattern, the pattern being provided in or on a surface of the item, the pattern forming a repetition of dots, a code being stored in a sequence of adjacent ones of the dots, processing the image to detect the pattern; deriving the code from the sequence of adjacent ones of the dots of the pattern; separating in accordance with the code the item the pattern from the waste. The pattern may be a relief pattern. The relief pattern may comprise a pattern of bumps and recesses. The pattern, such as in a form of a relief, may also be applied to identify the item.

Claims

1.-34. (canceled)

35. A method of waste separation, the method comprising: irradiating the waste by a source of radiation, capturing an image of the waste when irradiated by the source of radiation; wherein an item in the waste is provided with a pattern, the pattern being provided in or on a surface of the item, the pattern forming a repetition of dots, a code being stored in a sequence of adjacent ones of the dots, processing the image to detect the pattern; deriving the code from the sequence of adjacent ones of the dots of the pattern; separating in accordance with the code the item comprising the pattern from the waste, wherein the source of radiation provides floodlight irradiation along at least part of the surface of the item, wherein each dot forms a bump or recess of the surface of the item, the floodlight irradiation along at least part of the surface of the item forming by the dots an image of highlights and shades on the surface of the item, wherein capturing the image of the waste when irradiated by the source of radiation comprises capturing the image of highlights and shades, and wherein the code is derived from the captured image of highlights and shades.

36. The method according to claim 35, wherein the floodlight irradiation irradiates at an acute angle in respect of the surface of the item.

37. The method according to claim 36, wherein the floodlight irradiation irradiates at an angle between 1 and 30 degrees in respect of the surface of the item, preferably between 3 and 15 degrees in respect of the surface of the item.

38. The method according to claim 35, wherein the dots form leading and trailing edges of the surface of the item, and wherein the floodlight irradiation provides, seen along a direction of irradiation, for shades at the trailing edges of the surface of the item and highlights at the leading edges of the surface of the item.

39. The method according to claim 35, wherein the relief pattern is provided on an inside surface of the item, the item having been made from an at least partly transparent material, causing the relief pattern to be visible from the outside.

40. The method according to claim 35, wherein plural items are imaged at a time, the image being divided in plural image parts.

41. The method according to claim 35, wherein the dots of the pattern are coded into at least four different dot values, at least two of the dot values forming a code information dot value range, the remaining dot values forming a compensation dot value range, the dots having a dot value in the code information dot value range coding the code, the dots having dot values in the compensation dot value range balancing an average dot value of the pattern, a difference in deformation between dots having different dot values in the compensation dot value range being smaller than a difference in deformation between dots having different dot values in the code information dot value range.

42. The method according to claim 41, wherein a maximum height deformation of the dots in the code information dot value range is truncated.

43. The method according to claim 35, wherein the pattern is a redundant code.

44. The method according to claim 35, wherein the pattern repeats plural times on the surface of the item, the code being derived from a combination of fragments of neighbouring patterns.

45. The method according to claim 44, wherein the surface of the item is curved, neighbouring patterns are offset in respect of each other along a curvature of the surface of the item.

46. The method according to claim 35, wherein a shape of the bumps and/or recesses is symmetrical, seen along raster lines of the pattern.

47. The method according to claim 35, wherein a size of the bumps and/or recesses is progressive to a value of the dot of the pattern.

48. The method according to claim 35, wherein the sequence of adjacent ones of the dots is a pseudo random sequence.

49. The method according to 35, wherein the adjacent dots are arranged at a constant mutual distance, the dots comprising at least two differently shaped dots, the code being stored in a sequencing of the differently shaped dots.

50. The method according to claim 35, wherein the adjacent dots are arranged at a variable mutual distance, the code being stored in the variable mutual distance between the adjacent dots.

51. The method according to claim 35, wherein the sequence is a two dimensional sequence of a group of dots, the group comprising at least 100 times 100 dots, preferably at least 256 times 256 dots.

52. The method according to claim 35, wherein the pattern comprises at least 1024, preferably at least 4096, more preferably at least 8192 dots.

53. The method according to claim 35, wherein a pitch of the dots is at least 0.1 millimetres, preferably between 1 and 3 millimetres.

54. The method according to claim 35, wherein the code comprises a pointer to further waste separation information.

55. The method according to claim 35, wherein the code comprises at least one of a material type, a manufacturer identification code, a toxicity code and a material safety code.

56. The method according to claim 35, wherein the pattern comprises a relief pattern and wherein preferably the dots are formed by at least one of bumps and recesses.

57. The method according to claim 35, wherein the pattern repeats the code plural times.

58. The method according to claim 35, wherein the source of radiation comprises a polarized light source and wherein the capturing the image of the waste comprises: photographing the waste via a polarization filter.

59. The method according to claim 35, wherein the source of radiation emits waves in a millimeter wavelength range, and wherein the capturing the image of the waste comprises: imaging the waste in a wavelength range of the millimeter wavelength.

60. A method of manufacturing a recyclable item, the method comprising: providing a code representative of a recycling parameter of the item; forming the code into a pattern, the pattern forming a repetition of dots, the code being stored in a sequence of adjacent ones of the dots; and manufacturing the item, wherein the pattern is provided on or in at least part of a surface of the item, wherein each dot forms a bump or recess of the surface of the item, the dots being configured to form an image of highlights and shades on at least part of the surface of the item when irradiated by floodlight irradiation, the code being derivable from the image of highlights and shades.

61. The method according to claim 60, wherein the pattern is provided into the item by pressing a mold comprising the pattern into at least a part of the package.

62. An item, such as a package, comprising a pattern provided on or in a surface of at least part of the item, the pattern forming a repetition of dots, a code being stored in a sequence of adjacent ones of the dots, the code being representative of a recycling parameter of the item, wherein each dot forms a bump or recess of the surface of the item, the dots being configured to form an image of highlights and shades on at least part of the surface of the item when irradiated by floodlight irradiation, the code being derivable from the image of highlights and shades.

63. The item according to claim 62, wherein the code comprises at least one of a material type, a manufacturer identification code, a toxicity and a material safety code.

64. The item according to claim 62, wherein the pattern comprises a relief pattern and wherein the dots are formed by at least one of bumps and recesses.

65. The item according to claim 62, wherein a pitch of neighboring dots is at least 0.1 millimeters, preferably in a range of 1 to 3 millimeters.

66. The item according to claim 62, wherein the code comprises a pseudo random noise code.

67. The item according to claim 62, wherein the pattern repeats the code plural times.

68. The item according to claim 62, wherein the item is a package such as a bottle.

69. A mould for moulding an item, the mould being provided with a pattern to be moulded on or in a surface of at least part of the item, the pattern forming a repetition of dots, a code being stored in a sequence of adjacent ones of the dots, the code being representative of a recycling parameter of the item, wherein each dot forms a bump or recess of the surface of the item, the dots being configured to form an image of highlights and shades on at least part of the surface of the item when irradiated by floodlight irradiation, the code being derivable from the image of highlights and shades.

70. A method of identifying an item, the method comprising: irradiating the item by a source of radiation, capturing an image of the item when irradiated by the source of radiation; wherein the item is provided with a pattern, the pattern being provided in or on a surface of the item, the pattern forming a repetition of dots, an identification code being stored in a sequence of adjacent ones of the dots, processing the image to detect the pattern; deriving the identification code from the sequence of adjacent ones of the dots of the pattern; and identifying the item from the identification code, wherein the pattern comprises a relief pattern, wherein the source of radiation provides floodlight irradiation along at least part of the surface of the item, wherein each dot forms a bump or recess of the surface of the item, the floodlight irradiation along at least part of the surface of the item forming by the dots an image of highlights and shades on the surface of the item, wherein capturing the image of the waste when irradiated by the source of radiation comprises capturing the image of highlights and shades, and wherein the code is derived from the captured image of highlights and shades.

71. A method of manufacturing an item, the method comprising: providing an identification code representative of an identification parameter of the item; forming the code into a pattern, the pattern forming a repetition of dots, the code being stored in a sequence of adjacent ones of the dots; manufacturing the item, wherein the pattern is provided on or in at least part of a surface of the item, wherein the pattern comprises a relief pattern, wherein each dot forms a bump or recess of the surface of the item, the dots being configured to form a image of highlights and shades on at least part of the surface of the item when irradiated by floodlight irradiation, the code being derivable from the image of highlights and shades.

72. An item, such as a package, comprising a pattern provided on or in a surface of at least part of the item, the pattern forming a repetition of dots, a code being stored in a sequence of adjacent ones of the dots, the code being representative of an identification parameter of the item, wherein the pattern comprises a relief pattern, wherein each dot forms a bump or recess of the surface of the item, the dots being configured to form an image of highlights and shades on at least part of the surface of the item when irradiated by floodlight irradiation, the code being derivable from the image of highlights and shades.

73. A mould for moulding an item, the mould being provided with a pattern to be moulded on or in a surface of at least part of the item, the pattern forming a repetition of dots, a code being stored in a sequence of adjacent ones of the dots, the code being representative of an identification parameter of the item, wherein the pattern comprises a relief pattern, wherein each dot forms a bump or recess of the surface of the item, the dots being configured to form an image of highlights and shades on at least part of the surface of the item when irradiated by floodlight irradiation, the code being derivable from the image of highlights and shades.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0055] Further advantages, features and effects of the invention will become apparent from the enclosed drawings and corresponding description relating to a non-limiting embodiment of the invention, wherein:

[0056] FIGS. 1A and 1B depict examples of a product comprising a code;

[0057] FIG. 2A depicts a detailed view of an embodiment of a code formed into a two dimensional sequence of bits, and FIG. 2B depicts a view of an relief pattern derived from the two dimensional sequence of bits;

[0058] FIG. 3 depicts a waste separation device based on which the waste separation process will be explained;

[0059] FIG. 4 depicts a schematic, detailed view pf a part of a pattern;

[0060] FIG. 5 depicts a schematic cross sectional view of a part of a surface of an item without respectively with pattern in accordance with an embodiment of the invention;

[0061] FIG. 6 depicts an example of a code in accordance with an embodiment of the invention;

[0062] FIG. 7 schematically depicts a code and waste recycling parameter in accordance with embodiments of the invention;

[0063] FIG. 8 depicts a spectrum to explain wavelengths possibly to be applied in embodiments of the invention;

[0064] FIG. 9 depicts a schematic view of a mould according to an embodiment of the invention;

[0065] FIGS. 10A-10D depict patterns to illustrate successive steps of providing an item with a pattern, in accordance with aspects of the invention;

[0066] FIGS. 11A and 11B depict a view of amplitude of a pattern versus position along an x-axis;

[0067] FIGS. 12A-12C illustrate a deriving of the image of highlights and shades by floodlight irradiation in accordance with aspects of the invention; and

[0068] FIG. 12D illustrates a top view of a part of an image of highlights and shades in accordance with an aspect of the invention.

DETAILED DESCRIPTION OF THE INVENTION

[0069] FIG. 1 depicts an item IT, such as a product, in this example a bottle made of Polyethylene (also abbreviated as PET). The bottle may be formed by transparent or at least partly transparent polyethylene, i.e. the material exhibiting some degree of transparency. In the present example, the outside surface of the bottle is provided with a relief pattern. Alternatively, a part of the bottle, such as a zone that extends around a circumference of the bottle, may be provided with a pattern PA, such as a relief pattern. The relief pattern forms a repetitive pattern that repeats itself in both circumferential as well as vertical direction. The patterns is formed by a relief in the surface of the bottle, in this example in the outside surface of the bottle. The pattern is formed by a repetition of dots, whereby dots either store a digital 1 or a digital zero, by being formed as a bump or a recess, respectively Instead of such as single bit pattern, multi-bit patterns may be applied, e.g. 2 bit patterns employing different bump and recess heights. The information in the pattern is stored in a sequencing of adjacent ones of the dots. The information stored in the pattern may form a waste separation code. It will be understood that for other purposes, such as identification purposes, the information stored in the patterns may comprise any suitable information, such as an identification code to identify the item. The waste separation code may for example comprise information about a material type, a manufacturer, a contents, a toxicity of the item or its contents, etc.

[0070] FIG. 2B depicts a detailed view of the pattern PA forming an relief and provided in a surface of the bottle as depicted in FIG. 1. The relief pattern is provided in a surface of the bottle, and is formed by a patterns of bumps (extrusions) and recesses (intrusions). In the present example of PET-bottles, the surface at the inside and the outside of the bottle are parallel, but it is not necessary, for a transparent bottle one side may be without bumps and/or recesses. Internal reflections in the material of the transparent bottle may have an effect on readability of the pattern. In particular when using polarized light, the differences between both options may not influence to much as polarized light may minimize the internal reflections.

[0071] The relief pattern may be designed as follows: first, a code that is to be stored in the item is taken as a starting point. The code may be supplemented by further information, such as a checksum to perform error correction. The code is then formed into a two dimensional bit (dot) sequence 2DB, as depicted in FIG. 2A, wherein black and white represent 0 and 1 bit values or vice versa. Any suitable coding software may be used to form the two dimensional bit (dot) sequence, for example, use may be made of coding software as supplied by Digimarc corporation. Then the two dimensional bit sequence is formed into a relief pattern by forming a bit value 1 as a bum and bit value 0 as a recess or vice versa. This, information is stored by means of differences in shape of the dots provided on the surface of the bottle. Alternatively, information may be stored in a varying of a mutual distance between the dots. For example, each dot forms a bump, whereby a placement of the bump in respect of its neighbours associates to a bit value of that dot.

[0072] The dots may be placed at any suitable pitch. For example, in order to facilitate reading by a camera having a commonly used resolution, a dot pitch in an order or magnitude of 1-3 millimetre may be applied. The radiation provided by the source of radiation may also be daylight or light from common electrical light sources in a visible wavelength band such as LED lighting, incandescent lighting, fluorescent lighting, etc. Using high accuracy image pickup, a pattern having a smaller dot pitch, e.g. a pitch of 0.1 millimetre or larger, may be applied. The dots may have any suitable shape, such as circular, oval, square, etc. Neighbouring dots may touch each other so as to create a continuous pattern giving a pleasant visual appearance to a human observer, or a spacing may be provided between adjacent dots which may provide that the dots are more easy readable. The dots may have any height profile, e.g. parabolic, circular, pyramidal, square, etc. The same applies to bumps. The pattern may be formed from bumps and flat dots, recesses and flat dots, bumps and recesses, or any other form. Using bumps and recesses, a high amplitude difference between dots having a bit value 1 and dots having a bit value 0 may be provided, thereby facilitating the pickup of an imaging of the pattern.

[0073] FIG. 3A depicts a waste separation device in accordance with an aspect of the invention. The waste separation device comprises a feeder FD (such as a conveyor belt) that feeds a stream of waste items WI. A camera CA is provided that takes a sequence of photographic images of the waste items while passing through a field of view of the camera. The camera thereby takes at least one photographic image of each waste item. In order to enhance a readability of the pattern, a source of radiation LS may emit radiation onto the waste. For example the source of radiation may be formed by a floodlight that emits floodlight in a visible light wavelength band to the waste. A visibility of the pattern may be enhanced thereby so as to facilitate detection of the pattern. A data processing device DPD is connected to the camera and receives the images as generated by the camera. The data processing device is provided with an image recognition that searches the images for the occurrence of relief patterns and generates an code CD (i.e. data coded into the relief pattern) corresponding to the relief pattern when having detected a relief pattern. Any suitable image recognition technique may be applied. For example, in the case of the encoding using the Digimarc software, the decoding may be performed by associated software. The code provided in the pattern may non-encrypted, i.e. may be derivable from the pattern by anyone, i.e. without access restrictions. In another embodiment, the code may be provided in the pattern in an encrypted way. Thus, only when having a decryption key available, the code can be deciphered from the detected pattern. In the present embodiment, the data processing device transmits the code to a recycling server RS. The recycling server derives recycling information relating to the particular relief pattern. For example the recycling server provides information as to a type of material, a manufacturing location, a toxicity code, etc. The material type in the present embodiment provides that the bottle is made of Polyethylene. The manufacturer location provides where the bottle originates from. The toxicity code may provide information about a type of product that was stored in the particular package (e.g. in case a potentially toxic product was distributed in the package, such as a cleaning agent, a pharmaceutical substance, a detergent, a solvent, etc.). In such as situation, special recycling may be required, to prevent that a residue of such as substance enters into the regular recycling process. Accordingly, the server provides a code WSC that comprises recycling information which translates the relief pattern into recycling information. Alternatively, the code itself may be provided in the relief pattern so that forwarding the code to the server may be omitted.

[0074] Based on the code, the waste item is separated by a separator SP downstream of the camera. The separator is connected to the data processing device and the server and correspondingly receives the code from the server. The separator in this embodiment comprises a selector, such as a mechanic selector, e.g. a selector flap that pushes the waste item towards a corresponding discharging opening. At each discharging opening, a corresponding collection bin or discharging feeder DF is provided to allow for a collection resp. a feeding of the separated waste items. Instead of using visible light to irradiate the waste, use may be made of any other suitable radiation. For example use may be made of millimeter waves. In order to detect the waves, instead of the above mentioned camera, a suitable detector for detecting millimeter waves may be used. FIG. 3B depicts a similar setup as depicted in FIG. 3A. Additionally, a polarization filter PF is provided in front of the camera so as to filters the image to be received by the camera. Furthermore, use may be made of a light source emitting polarized light, in combination with the detection of the image of the waste using the polarization filter. Thereby, using a polarization filter at the camera, possibly in combination with the source of radiation emitting polarized light, unwanted reflections may be filtered out providing an improved imaging.

[0075] FIG. 4 depicts an example of a part of a pattern, namely a horizontal sequence of 8 dots, part of which are bumps (represented by black dots) and part of which are flat, represented by white dots. A cross sectional view being depicted in FIG. 4 for illustrative purposes. This example of a sequence of dots stores information, namely a binary sequence 01101100.

[0076] The code may be directly obtained from the dots. Thus, 01101100 may be or may form part of the stored code. Alternatively, any kind of encoding scheme may be used, such as a Digimarc encoding, a pseudo random noise encoding or any other suitable coding.

[0077] FIG. 5 schematically depicts how such a pattern may be provided on a surface SA of an item, such as a bottle. At a top side of FIG. 5, a part of a cross sectional view of a bottle is depicted, without pattern. At a bottom side of FIG. 5, a part of a cross sectional view of a bottle is depicted, with (a part of) a pattern PA.

[0078] FIG. 6 depicts an example of a code as may be stored in a pattern. The code in the present example comprises digit groups that provide information about Date D, Manufacturer of the item ID code MID, Manufacturer of a content of the item ID code MIC, Brand name BN, Brand owner BO, Country of production CP, Place of Production PP, Country of sale CS, Additions 1, 2, 3 ADD1, ADD2, ADD3 for future use, Warning 1 WA1, Warning 2 WA2. This code may be stored (directly or encoded) in the pattern. Alternatively, the pattern may contain a more brief code such as a watermark WM123456, which may be read from the pattern, decoded, sent to a server (such as recycling server RS in FIG. 3A) or other database (or otherwise) for obtaining the above code. In such as case, the code WM123456 as stored in the pattern forms a pointer to the above longer code. This may be useful to retrieve a large code (which would otherwise require large patterns to store the information directly in the pattern) from a smaller code a provided in the pattern.

[0079] FIG. 7 highly schematically depicts a recycling parameter RPM (exampled being described elsewhere in this document) derived from a code CD.

[0080] FIG. 8 depicts a spectrum showing Gamma rays Gr, X-rays XR, Ultraviolet UVR, visible light VL, Infrared IFR, Radio waves including Radar R, FM waves FM, TV waves TV, Short waves SW and Amplitude Modulation AM radio wavelengths. Centimeter/Millimeter wavelengths CMW are indicated also. Any such wavelength may be used by the source of radiation. For example visible light, UV and IR have been referred to above. Millimeter/centimeter waves may be applied and provide a good detectability as their wavelength may be in a same order of magnitude as the pitch of the pattern.

[0081] FIG. 9 depicts a mould MLD (such as an injection mould or blow injection mould) schematically indicating a part in which a pattern PA is provided. The pattern will be transferred onto a surface of the to be moulded item.

[0082] The techniques as described above may not only be used in the context of waste separation. Rather, the techniques may also be used to identify the item. For example, a relief pattern may be provided on an item and the relief pattern

[0083] The item is irradiated the item by a source of radiation, an image of the item when irradiated by the source of radiation, is captured; as described, the item is provided with a pattern, the pattern being provided in or on a surface of the item, the pattern forming a repetition of dot. The identification code is stored in a sequence of adjacent ones of the dots,

The image is processed to detect the pattern (e.g. using pattern recognition software);
The identification code is derived from the sequence of adjacent ones of the dots of the pattern. The item identified from the identification code. As mentioned, the pattern may comprise a relief pattern that forms a relief in or on a surface of the item. A set-up similar to that of FIG. 3 may be applied, however the selector may be omitted.

[0084] It is noted that the techniques as described in this document may apply to any item. The item may be a package, such as a package of a consumable, for example a bottle, a tray, a foil, a blister package, etc.

[0085] FIG. 10A depicts a print screen raster at 50% gray, without a pattern provided therein. FIG. 10B depicts the same print screen raster, however having a pattern superimposed thereon. The pattern comprises a raster of dots. Some of the dots have a higher grey level, thus being darker, while others have a lower grey level, thus being lighter. In the present example, the dots that are darker than the 50% grey level comprise information that codes the code, while the dots that are less dark than 50% grey level comprise compensation dots in order to average the intensity of the pattern back towards 50%.

[0086] In FIG. 10C, a (e.g. Gaussian) blurring filter has been applied to smoothen the print screen raster in which the dots have been formed. In FIG. 10D, an average intensity of the pattern has been reduced, as will be explained in some more detail in respect of FIGS. 11A and 11B

[0087] FIGS. 11A and 11B depicts a view of pattern intensity on the Y axis versus a position along the pattern on the x-axis. The pattern is superimposed on an average value AV of 50% grey, in accordance with FIGS. 10A and 10B. Hence, darker values above 50% are symbolized by the top parts of the curve and lighter values, below 50% are symbolized by the bottom parts of the curve. When using a code comprising code bit levels and compensation bit levels, the darker levels may for example comprise information from which the code can be derived, while the lighter parts comprise compensation bits to compensate an intensity level, thus bringing the average back to 50%. As the present example only aims to detect the code information, an asymmetry is provided, as depicted in FIG. 11B, where the average level, instead of 50% is brought to a low value (hence not being an average any more), thereby compressing the compensation range COMP, while increasing the code information range, CI, to emphasize code bits and compress compensation bits, thereby providing that a detectability of the code information may be improved. A resulting, lighter pattern is depicted in FIG. 10D.

[0088] FIG. 12A depicts a cross sectional side view of a pattern PA of bumps and/or recesses as may be obtained in accordance with the method as described with reference to FIG. 10A-10D. The dotted line in FIGS. 12A-12C represents a lower surface of the non-deformed item: in the present example, deformation in one direction, namely the outward direction, is applied only. The higher a gray level of the dots of the pattern of FIG. 10D, the more deformation is provided for the corresponding dot in the surface of the item IT. In the present example, deformation is provided by deforming upwardly in the plane of drawing, which may e.g. correspond to outwardly in the case of an item such as a bottle. FIG. 12B depicts a similar cross sectional view, however in this case the deformation is truncated TR, causing the tops to be flattened at a level of truncation.

[0089] FIG. 12C again depicts a cross sectional side view of a pattern PA of item IT, irradiated by floodlight FL from light source LS. The floodlight may be formed by any sort of radiation, e.g. visible, infrared, UV. As a result of irradiating the pattern by the floodlight, shades SH will be generated on the surface of the item, in particular at trailing edges of the deformation (seen in the direction of propagation of the floodlight). Similarly, highlights are generated at the leading edges (leading edges as seen in the direction of propagation of the floodlight). Thus (as the pattern extends over a surface of the item) an image of highlights and shades is generated. The image of highlights and shades is detected by camera CA. In the present example, the camera is positioned to detect a reflection of the floodlight. Alternatively, a screen may be positioned at the location of the camera in FIG. 12C, and a camera be positioned to image a reflection pattern from the surface of the item, as reflected onto the screen. An another alternative, the camera may be positioned vertically over the item, similarly to the camera position in FIGS. 3A and 3B. Making use of reflection, a large contrast image may be obtained, thus being able to improve detectability. The image of highlights and shades reflects the dots of the pattern. An example of an image of 2 dots DT is provided in FIG. 12D. For the purpose of illustration, FIG. 12D depicts intensity values by means of raster points. For each dot, a highlight HL is depicted at a left side thereof, while a shade SH is depicted at a right side thereof (in the present example, floodlight would have been irradiated from the left side). As follows from FIG. 12D, the more deformation respectively the larger a deformation dot, the longer (seen in the direction of propagation of the floodlight) respectively the wider (seen perpendicular to the direction of propagation of the floodlight( ) the shade will be. A similar consideration applies to the highlights. Hence, information concerning size and shape of the deformation of a dot can be derived from the size and shape of the shade and highlights. Highlight and shade size correlate to dot dimensions. The camera receives an image comprising a pattern (i.e. image) of highlights and shades caused by the deformations of the surface of the item, the code being derived from the captured pattern of highlights, the pattern of shades or both. In case both highlights and shades would be applied for detecting the code, the highlights could for example be inversed and translated to coincide with the shades. This would provide that the highlights and shades can be added or correlated, which may result in an increase in signal to noise ratio.

[0090] The pattern of bumps and recesses may repeat plural times on the surface of the item, so that, in case of e.g. damage to parts of patterns or deformation, the code may be derived from a combination of fragments of neighbouring patterns. In particular, when the surface of the item is curved (such as in the case of the bottle depicted in FIGS. 1A and 1B, neighbouring patterns are offset in respect of each other along a curvature of the surface of the item, so that, when a part of a pattern is not readable due to e.g. angle of incidence of the floodlight, another pattern of part thereof will be at another angle of incidence, thus increasing a likelihood of detecting the code.

[0091] A shape of the bumps and/or recesses may be symmetrical, seen along raster lines of the pattern (the dots may form a raster along raster lines), so that the pattern of shades may be less tolerant to an angle of incidence of the irradiation, causing readability to be improved even when e.g. the item is oriented randomly. A size of the bumps and or recesses may progressive to a value of the dot of the pattern, enhancing that a size of the shade of the dots to be progressive to the value of the bump and/or recess thus to the values of the dot.