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WO2017007340A1 - Système d'inspection d'article à faible angle pour un convoyeur - Google Patents

Système d'inspection d'article à faible angle pour un convoyeur Download PDF

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Publication number
WO2017007340A1
WO2017007340A1 PCT/NZ2016/050109 NZ2016050109W WO2017007340A1 WO 2017007340 A1 WO2017007340 A1 WO 2017007340A1 NZ 2016050109 W NZ2016050109 W NZ 2016050109W WO 2017007340 A1 WO2017007340 A1 WO 2017007340A1
Authority
WO
WIPO (PCT)
Prior art keywords
housing
window
articles
article
camera
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Ceased
Application number
PCT/NZ2016/050109
Other languages
English (en)
Inventor
Kenneth Barry MOYNIHAN
Michael Edmondson
Simon Knightley
Stefan TUCHSCHERER
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Compact Technologies Ltd
Original Assignee
Compact Technologies Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Compact Technologies Ltd filed Critical Compact Technologies Ltd
Publication of WO2017007340A1 publication Critical patent/WO2017007340A1/fr
Anticipated expiration legal-status Critical
Ceased legal-status Critical Current

Links

Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B07—SEPARATING SOLIDS FROM SOLIDS; SORTING
    • B07C—POSTAL SORTING; SORTING INDIVIDUAL ARTICLES, OR BULK MATERIAL FIT TO BE SORTED PIECE-MEAL, e.g. BY PICKING
    • B07C5/00—Sorting according to a characteristic or feature of the articles or material being sorted, e.g. by control effected by devices which detect or measure such characteristic or feature; Sorting by manually actuated devices, e.g. switches
    • B07C5/34—Sorting according to other particular properties
    • B07C5/342—Sorting according to other particular properties according to optical properties, e.g. colour
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B07—SEPARATING SOLIDS FROM SOLIDS; SORTING
    • B07C—POSTAL SORTING; SORTING INDIVIDUAL ARTICLES, OR BULK MATERIAL FIT TO BE SORTED PIECE-MEAL, e.g. BY PICKING
    • B07C2501/00—Sorting according to a characteristic or feature of the articles or material to be sorted
    • B07C2501/009—Sorting of fruit
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
    • G01N21/84—Systems specially adapted for particular applications
    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03B—APPARATUS OR ARRANGEMENTS FOR TAKING PHOTOGRAPHS OR FOR PROJECTING OR VIEWING THEM; APPARATUS OR ARRANGEMENTS EMPLOYING ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ACCESSORIES THEREFOR
    • G03B11/00—Filters or other obturators specially adapted for photographic purposes
    • G03B11/04—Hoods or caps for eliminating unwanted light from lenses, viewfinders or focusing aids
    • G03B11/045—Lens hoods or shields
    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03B—APPARATUS OR ARRANGEMENTS FOR TAKING PHOTOGRAPHS OR FOR PROJECTING OR VIEWING THEM; APPARATUS OR ARRANGEMENTS EMPLOYING ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ACCESSORIES THEREFOR
    • G03B17/00—Details of cameras or camera bodies; Accessories therefor
    • G03B17/02—Bodies

Definitions

  • the invention generally relates to the field of article conveying systems, article inspection systems and article sorting systems. More particularly, the invention relates to a system for imaging articles at a low angle on such systems.
  • Conveyors are often used in grading machines to transport articles through various
  • a common type of object that is graded and sorted by such a conveyor system is fruit.
  • Fruit may be sorted based on criteria such as weight, shape, colour, ripeness and any other characteristic.
  • Conveyor systems com prise devices to measure these characteristics while the fruit is being transported.
  • the characteristics can be detected and measured by visual scanning devices positioned above the conveyor.
  • the position of each fruit and its respective characteristics can be tracked so that a discharge mechanism causes items of fruit to be unloaded from the conveyor and sent to the required destination, for example towards a chute or onto another conveyor.
  • Similar systems can be used to grade and sort other types of product based on similar characteristics or other characteristics specific to the type of product.
  • Many common fruit defects can be detected by existing fruit inspection means, which may be provided to a conveyor system.
  • typical existing inspection systems are set up with the cameras spaced far away from the fruit to avoid contact with the fruit or the associated debris.
  • the allowable horizontal spacing of a camera from a lane of a conveying system is often limited to allow for multiple lanes to run parallel in the same conveying system, the cameras on typical inspection systems image the fruit from high angles, to achieve the required spacing from the fruit and conveyors.
  • Some fruit tend to assume a position on conveyors with an orientation in which the major axis of the fruit (for example the axis between the stalk and calyx in the case of an apple) lies in the horizontal plane. While this orientation offers some advantages for existing vision systems and allows for gentle handling of the fruit, the high angles of the cameras of existing systems often results in poor inspection of the stem or calyx region of the fruit.
  • the path length between the fruit surface and the camera in the system was not sufficiently different to the path length between the mirror and the camera and this meant any blemishes or debris on the mirror had a tendency to be in focus, which often lead to the camera incorrectly registering the blemish as a defect on the fruit.
  • a housing for a sensor configured to inspect articles conveyed past the housing by an article conveyor along a conveying path in a conveying direction from upstream to downstream and substantially at the level of the sensor, the housing comprising:
  • a body having formed therein a window, the window configured to, in use, allow the sensor to inspect articles on the conveying path;
  • shielding means configured to, in use, substantially protect the window from items projected from the article conveyor.
  • the shielding means is configured to, in use, shield the window from debris projected from the articles and/or the article conveyor.
  • the window is inset from an outer wall of the body.
  • the shielding means comprises a part of the body positioned, in use, closer to the conveying path than the window and upstream of the window.
  • the body comprises a first substantially vertical side wall extending between the window and the outer wall on an upstream side of the window and a second substantially vertical side wall extending between the window and the outer wall on a downstream side of the window, the first side wall having a greater angle relative to the conveying direction that the second side wall.
  • the second side wall curves away from the window towards the conveying direction.
  • the shielding means comprises a member projecting outwardly from the body on the upstream side of the window.
  • the shielding means comprises means configured to, in use, protect the window from any of the articles falling, or having fallen, off the article conveyor.
  • the body comprises a lower wall below the window sloping downwards towards the conveying path. More preferably, the lower wall extends between the window and the outer wall. More preferably, the outer wall comprises a substantially vertical portion positioned below the lower wall.
  • the body comprises an upper wall above the window sloping downwards towards the conveying path. More preferably, the upper wall extends outwards from the window.
  • the outer wall of the body slopes downwards towards the conveying path, the outer wall being configured for redirecting articles that have deviated from the conveying path downwards and towards the conveying path.
  • the shielding means comprises one or more protective members arranged generally in front of the window. More preferably, the one or more protective members comprise one or more bars.
  • the body comprises one or more apertures configured to allow, in use, a flow of gas to be projected between the window and the conveying path.
  • the one or more apertures are provided on the upstream side of the window. More preferably, one or more of the apertures is positioned so that, in use, a flow of gas is projected across an outer surface of the window. More preferably, one or more of the apertures is positioned so that, in use, a flow of gas is projected across the lower wall.
  • the housing is configured to house a camera configured to image articles conveyed past the housing.
  • the housing comprises a light source configured to, in use, illuminate the articles on the conveyor.
  • the light source illuminates the articles by providing light through the window.
  • the light source illuminates the articles by providing light through a periphery of the window. More preferably, the housing is configured so that, in use, the camera is positioned to image the articles through a centre portion of the window. More preferably, the light source illuminates the articles by providing light through the outer periphery of the window surrounding the centre portion.
  • the window comprises a diffuser to diffuse the light provided by the light source.
  • the light source is spaced from the diffuser.
  • the housing comprises surfaces between the light source and the diffuser, the surfaces comprising one or more reflective surfaces.
  • the light source generates light over a larger surface area than the area of the window through which the light source illuminates the articles.
  • the housing comprises a first polarising element for polarising light generated by the light source illuminating the articles, and a second polarising element for polarising light reflected off the articles before being received by the camera, the first and second polarising elements having transmission axes aligned substantially perpendicular to each other.
  • a housing for a sensor configured to inspect articles conveyed past the housing by an article conveyor along a conveying path in a conveying direction from upstream to downstream and substantially at the level of the sensor, the housing having formed therein a window, the window configured to, in use, allow the sensor to inspect articles on the conveying path, and the housing comprising one or more apertures configured to allow, in use, a flow of gas to be projected between the window and the conveying path.
  • the one or more apertures are provided on the upstream side of the window. More preferably, one or more of the apertures is positioned so that, in use, a flow of gas is projected across an outer surface of the window. More preferably, one or more of the apertures is positioned so that, in use, a flow of gas is projected across a lower wall below the window.
  • the housing comprises shielding means, the shielding means configured to, in use, substantially protect the window from items projected from the article conveyor.
  • the shielding means is configured to, in use, shield the window from debris projected from the articles and/or the article conveyor.
  • the housing comprises a body and the window is inset from an outer wall of the body.
  • the shielding means comprises a part of the body positioned, in use, closer to the conveying path than the window and upstream of the window.
  • the body comprises a first substantially vertical side wall extending between the window and the outer wall on an upstream side of the window and a second substantially vertical side wall extending between the window and the outer wall on a downstream side of the window, the first side wall having a greater angle relative to the conveying direction that the second side wall. More preferably, the second side wall curves away from the window towards the conveying direction.
  • the shielding means comprises a member projecting outwardly from the body on the upstream side of the window.
  • the shielding means comprises means configured to, in use, protect the window from any of the articles falling, or having fallen, off the article conveyor.
  • the body comprises a lower wall below the window sloping downwards towards the conveying path. More preferably, the lower wall extends between the window and the outer wall. More preferably, the outer wall comprises a substantially vertical portion positioned below the lower wall.
  • the outer wall of the body slopes downwards towards the conveying path, the outer wall being configured for redirecting articles that have deviated from the conveying path downwards and towards the conveying path.
  • the shielding means comprises one or more protective members arranged generally in front of the window. More preferably, the one or more protective members comprise one or more bars.
  • the housing is configured to house a camera configured to image articles conveyed past the housing.
  • the housing comprises a light source configured to, in use, illuminate the articles on the conveyor.
  • the light source illuminates the articles by providing light through the window.
  • the light source illuminates the articles by providing light through a periphery of the window. More preferably, the housing is configured so that, in use, the camera is positioned to image the articles through a centre portion of the window. More preferably, the light source illuminates the articles by providing light through the outer periphery of the window surrounding the centre portion.
  • the window comprises a diffuser to diffuse the light provided by the light source.
  • the light source is spaced from the diffuser.
  • the housing comprises surfaces between the light source and the diffuser, the surfaces comprising one or more reflective surfaces.
  • the light source generates light over a larger surface area than the area of the window through which the light source illuminates the articles.
  • the housing comprises a first polarising element for polarising light generated by the light source illuminating the articles, and a second polarising element for polarising light reflected off the articles before being received by the camera, the first and second polarising elements having transmission axes aligned substantially perpendicular to each other.
  • a sensor mounted within the housing and configured to inspect articles on the article conveyor substantially at the level of the sensor.
  • the article inspection device comprises flow generation means for generating a flow of gas for projecting through the one or more apertures.
  • the sensor comprises a camera configured to image articles on the article conveyor.
  • one or more article conveyors configured to convey articles along a conveying path; one or more article inspection devices according to the third aspect of the invention, the or each article inspection device being configured to inspect the articles at a point on the conveying path.
  • an article sorting system comprising:
  • discharge means for selectively discharging articles from the article conveyors to one or more discharge locations.
  • the sorting system comprises means for controlling the discharge means based on analysis of data captured by the sensor. More preferably the or each sensor comprises a camera and the sorting system comprises means for controlling the discharge means based on analysis of image data captured by the camera.
  • the sorting system comprises means for generating data indicative of how the articles should be sorted dependent on the analysis of the images.
  • the sorting system comprises analysis means for receiving image data based on the images and analysing the image data to determine characteristics of the imaged articles.
  • an article inspection system comprising:
  • one or more article conveyors configured to convey articles along a conveying path
  • one or more article inspection devices configured to inspect the articles at a point on the conveying path, the or each article inspection device being positioned substantially at the level of the sensor and comprising:
  • a housing configured to, in use, image articles at a point on the conveying path;
  • a light source configured to, in use, illuminate the articles on the conveyor, wherein the camera and the light source are housed in the housing.
  • Figure 1 is a perspective view illustration of a housing for a camera for use in an article inspection system according to an embodiment of the invention
  • Figure 2 is a plan view illustration of the housing of Figure 1 alongside a conveyor;
  • Figure 3 is an elevation view illustration of the housing of Figure 1;
  • Figure 4 is a perspective view illustration of an article inspection device, according to an embodiment of the invention, alongside a conveyor;
  • Figure 5 is a perspective cross-section view illustration of the article inspection device of
  • Figure 6 is a side cross-section view illustration of the article inspection device of Figure
  • Figure 7 is a plan cross-section view illustration of the article inspection device of Figure
  • FIG. 4; and Figures 8-11 are isometric view illustrations of housings for a camera for use in an article inspection system according to further embodiments of the invention. Detailed Description of Preferred Embodiments of the Invention
  • the applicant has identified that, in a fruit inspection and/or sorting system in which fruit are conveyed along a plurality of conveyor paths, positioning cameras at a high angle to fruit to be inspected, in particular when the fruit lies with the axis between its stem and calyx in a horizontal plane, can lead to poor inspection of the stem and calyx regions for the following reasons:
  • the image resolution obtained in the stem and calyx regions is low in comparison to other regions of the fruit, due to the tangential relationship between the fruit surface in those regions and the line-of-sight of the camera. In some cases, the orientation of the fruit and properties of the lens used may result in a defect area not being inspected at all.
  • FIG. 1 shows a housing 1 for a camera for use in an article inspection system.
  • housing 1 is a sealed, protected and self-cleaning unit which, in use, enables a camera housed within the housing 1 to better detect some types of fruit defects that are commonly missed with prior art vision systems.
  • Housing 1 is configured to be installed alongside an article conveyor, such as an endless conveyor, so that the articles conveyed on the conveyor can be imaged by the camera from a substantially horizontal angle as they pass the camera along a conveying path in a conveying direction from upstream to downstream. That is, the housing is configured to be positioned so that the camera is positioned at substantially the same vertical level as the articles carried by the conveyor. This enables more effective inspection of the sides of articles, given the direct angle of the camera on the side of the articles and the close proximity of the camera to the articles.
  • the physical design of the housing 1 includes multiple features which increase the tolerance of imaging equipment housed within the housing to debris, i.e. to reduce the impact by debris on the ability of the imaging equipment to inspect the fruit for the purposes of effective fruit inspection and consequential sorting. In other embodiments of the invention any combination of one or more of these features may be present.
  • “Debris” can include various physical matter that can reduce the ability of a camera to clearly image fruit if the debris lies in the line-of-sight between camera and fruit, such as dust, water, pieces of fruit etc. “Debris” can also include physical matter that reduces the quality of illumination of the fruit to be imaged. In general, debris is any matter that impacts the ability of the camera to acquire an adequate image of an adequately illuminated fruit, where "adequate" means of sufficient quality to be able to inspect the fruit to be able to sort the fruit with the desired level of error tolerance.
  • housing 1 reduces the direct paths available for debris to contact optically critical surfaces from the upstream direction. It may also go some way to reducing the risk of debris approaching from the downstream direction as well.
  • Housing 1 comprises a body 2 configured to support and house a camera therein.
  • Body 2 comprises a window 3 behind which the camera is able to be mounted so that the camera's lens (or lenses) receives light through the window 3 from fruit conveyed by a conveyor in front of housing 1.
  • the window 3 preferably comprises a transparent panel to provide a physical barrier between the camera and the conveyor alongside which the housing 1 is mounted, although in some embodiments the window may be an opening in body 2.
  • the body 2 also comprises shielding means to protect the window 3.
  • the shielding means may comprise a number of elements and may protect the window 3 in a number of ways from different risks to optically important components.
  • One type of protection the shielding means provides to the window 3 is protection from debris projected from the articles and/or the article conveyor. Dust or other particulate matter may be cast off the articles or article conveyor during use. Given the velocity of the articles and article conveyor in the conveying direction, debris that they cast off will also have a component of velocity in this direction. This means that, from the perspective of housing 1, most debris will be directed towards the housing 1 from the upstream direction (i.e. outwards from the conveyor in the downstream direction). Housing body 2 is therefore designed to reduce the possibility of debris contacting window 3 from this direction, as will now be explained.
  • the window 3 is advantageously inset into the housing 1, i.e. it is spaced backwards from a front outer wall of body 2.
  • a projecting part 100 of the body 2 is positioned, in use, closer to the conveyor (and conveying path) than window 3 and upstream of the window.
  • projecting part 100 helps protect the window from debris carried with the articles being conveyed.
  • projecting part 100 blocks the path of the general direction of debris being projected from the conveyed articles or conveyor which, as explained is outwards from the conveyor in a downstream direction.
  • debris would need to make a sharp and relatively unlikely change of direction from its projected direction to turn the corner around the downstream edge of projecting part 100 in order to contact window 3.
  • projecting part 100 needs to extend forward of window 3 to adequately protect the window from debris cast off by the conveyor will depend on a number of factors, for example the speed of the conveyor, the amount and type of debris being cast off, and the distance between the housing 1 and the conveyor. These factors can be considered for each installation and the necessary distance of projecting of projecting part 100 can be readily determined.
  • window 3 While the main risk of debris to window 3 is from the upstream direction, debris may also be projected towards the window from other directions.
  • the inset position of window 3 from the front outer wall helps to reduce the chances of debris landing on or in front of window 3 from all directions.
  • Body 2 comprises a first substantially vertical side wall 6 which, in use, extends between window 3 and the front outer wall at the downstream edge of projecting part 100.
  • Side wall 6 extends away from the window towards front of the body (i.e. towards the conveying path) substantially perpendicular to the conveying direction or at an angle towards the upstream direction.
  • the first side wall 6 is closer to perpendicular to the conveying direction than it is to parallel with the conveying direction, which causes the window to be sheltered more effectively by the downstream end of projecting part 100 compared to if the side wall 6 had a shallower angle to the conveying direction.
  • side wall 6 may form an angle of between 50° and 80° to the conveying direction in some embodiments. If window 3 is set further back from the front wall of the body 2, this may allow for a shallower angle of first side wall 6 since the shielding front limb of body 2 would be larger and create an adequate shielding effect even if side wall 6 is angled more shallowly.
  • Body 2 also comprises a second vertical side wall 7 which, in use, extends between window 3 and the front outer wall at an upstream edge of a projecting part of body 2 downstream of the window 3.
  • Side wall 7 extends away from the window 3 towards the conveying path on an angle towards the downstream direction.
  • the second vertical side wall 7 is closer to parallel with the conveying direction than perpendicular to the conveying direction, which reduces the chance of debris being caught in the inset region just downstream of window 3.
  • the second vertical side wall 7 curves away towards the conveying direction to further reduce the chance of impeding the flow of any debris passed the window. That is, the angle of side wall 7 relative to the conveying direction reduces for portions of the side wall 7 further away from window 3.
  • a part of side wall 7 close to window 3 may form an angle in the range 30° to 45° to the conveying direction and a part of the side wall 7 further from the window 3 may form a shallower angle to the conveying direction, for example in the range 10° to 30°.
  • Body 2 comprises a lower wall 8 below window 3 which is sloped downwards away from window 3 extending to the front outer wall and towards the conveying path.
  • the slope on lower wall 8 reduces the chance of debris collecting on the lower wall.
  • the body 2 may also comprise an upper wall 9 above the window 3 which slopes downward from above the window 3 to a point slightly below the top of window 3 and proud of the window 3. This reduces the chance that debris falling from above the frame 4 will contact the window 3, and may deflect falling debris away from the window.
  • Another type of protection the shielding means provides to the window 3 is protection from fruit (or other articles) that falls off the article conveyor, or fruit that has fallen off the article conveyor upstream of the housing 1 and is pushed along beside the conveyor.
  • Lower wall 8 contributes to protecting window 3 in this regard as the upward slope of lower wall towards the window 3 would mean fruit would have to roll up the lower wall to contact window 3.
  • body 2 comprises a bottom wall portion 10, which is substantially vertical.
  • Wall portion 10 extends from the front edge of lower wall 8 downwards.
  • Wall portion 10 provides a vertical barrier to make it difficult for fruit that has fallen off the conveyor in front of housing 1, or has been dragged along between the conveyor and the housing 1, to block the view of the camera or get up onto lower wall 8 and risk contacting window 3. Any fruit that is positioned in front of housing 1 should be at a sufficiently lower level not to block the line-of-sight from the camera to the fruit on the conveyor.
  • the housing 1 has a roughly upturned V-shape with a flat top.
  • the upturned V-shape is advantageous in redirecting errant fruit or pieces of fruit back towards the conveying path.
  • the housing may have another shape generally promoting re-direction of fruit back towards the conveying path, for example an upturned U- shape.
  • the shape of the back of the housing 1 is less important than the shape of the front outer wall in this regard.
  • the front outer wall of the body slopes downwards towards the conveying path.
  • the window 3 and the opening of the body 2 around the window 3 are smaller than the fruit to be conveyed past the window 3, such that the body 2 is able to protect the window 3 from errant fruit.
  • Figure 2 shows a close up plan view of a part of the housing 1 alongside a conveyor 11 carrying an article 12, which may be a fruit such as an apple.
  • the conveying direction is identified as the direction 25.
  • Figure 3 shows a close up elevation view of part of housing 1, from the front (i.e. from the direction of an article to be imaged located in front of the window 3).
  • the shape of the first and second vertical side walls 6 and 7 can be seen in these views.
  • There is little space in the inset region on the upstream side of the window 3 and the space within the inset region in front of the window 3 opens up towards the downstream direction.
  • This difference between the size of the volume of the inset region upstream and downstream of the window is created by the angle of the first side wall 6 to the conveying direction being larger than the angle of the second side wall 7 to the conveying direction.
  • FIG. 1-3 Also visible in Figures 1-3 is the use of radii to form smooth transitions at the edges between the walls of the body 2.
  • vertical wall portion 10 is connected to lower wall 8 by a curved transition section or lip 101
  • vertical side wall 6 is connected to lower wall 8 by a curved transition section 102.
  • the edges of the aperture in body 2 which form the opening for window 3 curve inwardly towards the opening.
  • the inset region in front of the window 3 is generally large enough that it can easily be cleaned, in particular by a person that must reach from an external location and is in an unsighted position.
  • the shape of the housing 1 preferably does not include features that increase the likelihood of fruit damage, such as points, sharp ridges or protrusions, poor fruit containment or other catch points.
  • body 2 may comprise an inset portion or frame 4.
  • Frame 4 may be mounted to an outer shell portion of body 2 to define the inset region in which the window 3 is mounted.
  • the outer shell portion may itself form an aperture within which frame 4 is mounted.
  • Frame 4 may be removable from the shell of body 2 for ease of cleaning, access to components housed inside housing 1 or to enable frames of other configurations to be used in the housing, for example frames defining larger or smaller windows.
  • FIGS 8-11 are isometric view illustrations of housings 1 for a camera for use in an article inspection system according to other embodiments of the invention. Compared to Figure 1, like reference numbers are used to indicate like features.
  • the housing 1 in the embodiment of Figure 8 is similar to the housing of Figure 1.
  • the overall shape of the housing 1 in Figure 8 is box-like and the front wall of the housing is substantially vertical.
  • the first side wall 6, which is located between window 3 and the front outer wall at the downstream edge of projecting part 100, has a substantially uniform width over its entire height. This may mean that the window 3 is shielded from debris as well near the top of the window as near the bottom of the window.
  • housing 1 comprises a projecting part 100 on the upstream side of window 3 that projects outwardly from the housing body 2. This increases the depth of side wall 6 compared to side wall 7 and helps to shield window 3 more effectively from debris incident on the window 3 from the upstream direction.
  • Projecting part 100 may take the form of a ramp that projects further out from body 2 closer to window 3, i.e. projecting part 100 has a front wall that is angled towards the conveyor. This ramp structure helps to guide articles that have fallen off the conveyor away from window 3 and the inspection area in front of the window.
  • Figure 10 shows a housing 1 according to another embodiment of the invention that includes a projecting part 100 in the form of a ramp.
  • window 3 is not recessed into body 2, unlike the window in the embodiments of Figures 1, 8 and 9.
  • Projecting part 100 acts to shield window 3 from debris from the upstream direction and also diverts articles away from the area in front of window 3.
  • FIG 11 illustrates a housing 1 according to another embodiment of the invention.
  • Housing 1 comprises one or more protective members 120 that act to prevent articles or debris contacting window 3.
  • protective members 120 take the form of two horizontal bars or rails arranged in front of window 3 and spaced apart so that the imaging equipment inside housing 1 has a line of sight of articles on the conveyor between the bars.
  • one or more bars may be provided.
  • one or more of the bars may be arranged in another orientation, for example vertically or diagonally.
  • the housing may comprise a combination of bars in different orientations, for example horizontal and vertical bars, for example arranged in a grid or joined together in a grill or mesh.
  • other types of protective members 120 may be used, for example columns projecting outwardly from the front face of housing 1.
  • window 3 is recessed in the embodiment shown in Figure 11, in other embodiments the protective members 120 may be provided across a non-recessed window 3.
  • apertures 13 in housing 1 are another feature of the housing 1 that is advantageous for protecting the window 3 from debris.
  • the apertures 13 are configured to allow a flow of gas to be projected at positive pressure in the space between the window and the conveying path, i.e. in front of the window.
  • flow generation means may be contained within the housing 1. Alternatively, flow generation means may be provided separate from the housing 1.
  • the flow generation means may take the form of an impeller driven by a motor, or a pump.
  • the apertures 13 may be fluidly connected to the flow generator by one or more fluid conduits.
  • the gas projected through the apertures is air although, in other embodiments, other gases may be used.
  • the air flow apertures 13 are on the upstream side of window 3, to generate a flow in the same direction as the conveying direction to urge debris to continue past the window 3 without making contact.
  • the apertures may be positioned on a downstream side of the window and may project a flow of air in front of the window in an upstream direction.
  • the apertures may be positioned above or below the window.
  • the housing comprises apertures positioned to project a flow of gas in front of the window in a plurality of directions.
  • Aperture 13a is positioned so that a flow of air is projected across the front or outer surface of the window 3.
  • Apertures 13b are positioned so that a flow of air is projected across the surface of the lower wall 8.
  • the apertures may be shaped in such a way to effect the manner in which air is projected therefrom.
  • the air flow apertures 13 project an air flow in front of window 3 in the form of one or more air "curtains" and the apertures may be slit-shaped or otherwise elongate to create such an effect.
  • an article inspection device comprising housing 1 comprises both the shielding configuration explained above and means for generating a flow of gas in front of the window.
  • some embodiments of the invention incorporate these features independently of the other.
  • the air flow may be constant or may be variable, for example pulsing or intermittent.
  • the air path may be configured so that the air first flows past the camera or electronic components, such as light sources, housed within housing 1 to cool these components prior to exiting the housing through the air flow apertures.
  • Figure 4 shows a perspective view of an article inspection device 14 in the form of a housing 1 containing a camera 15 mounted inside the housing behind a window 3.
  • the article inspection device 14 is positioned alongside a conveyor 11 carrying an article 12 to be imaged by the camera 15.
  • Figure 5 shows a perspective cross-section view of the article inspection device 14, in particular showing details of the camera 15.
  • the camera 15 advantageously comprises a small body 16 and lens 17 in order to be constrained to a tight working envelope and operating environment.
  • Device 14 is configured to be positioned adjacent to a conveyor so that the camera 15 is at substantially the same level of the inspected fruit. For ease of focussing it is generally better for the camera 15 to be positioned further from the inspected fruit.
  • the ability to position the camera 15 a long way from the fruit is constrained in a conveyor system that may have multiple conveying lanes and therefore limited space between lanes.
  • the small form factor camera and lens offer the related advantages of reducing the area of the lens aperture, and allowing for an axially centralised source of illumination, which will be described below.
  • Reducing the area of the lens aperture, and increasing its distance from the articles to be imaged improves the device's tolerance to the presence of particles/debris that may reduce the quality of imaging.
  • reducing the aperture area a smaller surface is exposed to the production environment, which reduces the likelihood of particles/debris contacting the optically critical surface of the window, behind which the camera is mounted.
  • the window can be left out of the camera's depth of field. Therefore when debris is present on the window it will be out of focus, given the debris will be significantly closer to the camera than the article on which the camera is intended to focus. This means the debris is more likely to be captured as a gentle blur across an area of the image, rather than a small high contrast artefact.
  • imaging and the like, unless the context clearly requires otherwise.
  • the term “camera” is used in this specification to refer to a device for capturing a nd/or sensing light, including visible and non-visible light. It will be understood that, in any of the
  • sensors including, but not limited to: other types of light sensors; heat sensors; spectrometers; magnetometers; range sensors and noise sensors (e.g. microphones). These other types of sensors may be substituted for the camera in the described embodiments or may be used in addition to the described cameras.
  • Housing 1 comprises one or more light sources configured to, in use, illuminate the articles on the conveyor. Given article inspection device 14 is positioned adjacent to and at a similar level to the fruit, it is generally advantageous if the light sources are positioned in a similar position. This enables the parts of the fruit imaged by the camera in device 14 to be well illuminated. In some embodiments of the invention, the light source(s) illuminates the fruit by shining light through the window in the device housing. In this way the light sources may be housed inside housing 1.
  • the camera 15 is mounted centrally with respect to the window 3, which in this embodiment is substantially square-shaped.
  • the lens 17 of the camera 15 has a diameter smaller than the width and height of the window 3.
  • the window 3 therefore comprises a lens region 18 through which the camera images the fruit.
  • the body 16 of the camera 15 has a width and height that is very similar to the diameter of the lens 17. In this embodiment the body 16 has a square cross section.
  • the light source 20 comprises a plurality of LEDs 21.
  • the light source 20 provides light through an illumination portion 19 of window 3.
  • the light source 20 surrounds the body 16 of the camera 15 to provide illumination coaxially with the principal axis of the lens 17 through the illumination portion 19.
  • the light source may provide light through another part of the window 3, for example through another peripheral part.
  • This manner of providing coaxial illumination, or illumination from a position close to the position of the camera reduces the risk of shadows which may be incorrectly identified as defects on an article when the article is illuminated from one angle, yet imaged from another angle.
  • This is particular advantageous for very close inspection distances, such as in the present invention, and especially given the present invention allows for close inspection of complex article geometry such as the calyx and stem regions of fruit, which can easily create shadows if illuminated from an angle to the axis between the calyx and stem.
  • a diffuser 22 is provided on the inside of the window 3 behind the illumination portion 19 around the lens portion 18 of the window 3, so that light from the light source 21 passes through the diffuser 22 before exiting the housing 1.
  • the diffuser 22 helps to illuminate articles with the light from the multiple LEDs 21 evenly, which is generally desirable, given uneven illumination of the articles to be imaged can impact on the quality of the images, and ability of the imaging system to analyse them accurately.
  • the diffuser may be positioned in another location, for example in front of the window 3 or closer to the light sources.
  • Figures 6 and 7 show cross-section side and plan views, respectively, of the article inspection device 14 installed alongside a conveyor 11 carrying an article 12 to be imaged.
  • the article inspection device 14 also comprises reflective surfaces 23 between the light source 20 and the illumination portion 19 of window 3.
  • reflective surfaces 23 are on the outside of the camera body 16, and across from the camera body 16 on each side between the perimeter of the light source 20 and the window 3, to form a light box coaxially around the camera 15.
  • the reflective surfaces 23 guide the light generated by the light source 20 towards the illumination portion 19 of the window 3, increasing the amount of light provided to the article to be illuminated.
  • the LEDs 21 are mounted on a planar board. Positioning the LEDs 21 back from window 3 enables the surface area of the planar board to be wider than the window 3, if desired, as there is more space inside housing 1 away from its outer walls. This enables a larger number of LEDs 21 to be used.
  • the reflective surfaces 23 on the outside of the camera body 16 facing outwards and the corresponding reflective surfaces 23 facing inwards funnel the light from the larger surface area of light source 20 through the smaller area of the illumination portion 19 of window 3.
  • This light box design enables the provision of high light intensity, and high diffusion of light.
  • the larger surface area of the light source compared to the illumination portion of the window allows for more light to be emitted from the housing through the window than would otherwise be the case.
  • the light source is spaced from the window and diffuser element, the light travels through an increased distance before reaching the diffuser.
  • the longer light path, especially with reflections within the light box, increases the amount of light scatter prior to reaching the diffuser and results in more diffused illumination emitted from the window.
  • polarising elements on both the light output path from and light input path to the article inspection device 14.
  • a first polariser element can be provided to the illumination portion 19 of the window 3, for example on the inside of housing 1 between the diffuser 22 and the window 3.
  • a second polariser element can be provided to the lens portion 18 of the window 3, for example on the inside of the housing 1 between the window 3 and the lens 17 of the camera 15. If the first and second polarising elements are chosen or oriented so that their transmission axes are aligned substantially perpendicular to each other, then the specular or mirror-like reflections, which maintain polarisation, should be reduced in the acquired images.
  • the window may comprise two separate components forming the lens portion and the illumination portion.
  • the lens portion of the window and the illumination portion of the window may each be a polarising element.
  • Article inspection device 14 may be comprised as part of an article inspection system that inspects articles as they are conveyed by conveyors. Inspection of the articles is performed by image capture means, such as the camera housed inside device 14. Other cameras may also be part of the inspection system, including cameras in other locations.
  • the article inspection system may also be part of an article sorting system.
  • the article sorting system comprises processing means for analysing the images of the inspected articles and generating data as to how the articles should be sorted.
  • the processor controls means for discharging the articles from the conveyors based on the analysis of the images of the articles, for example to multiple destination locations based on size, colour, weight or any other characteristic of the articles, to sort the articles based on the results of the inspection.
  • the invention may also be said broadly to consist in the parts, elements and features referred to or indicated in the specification of the application, individually or collectively, in any or all combinations of two or more of said parts, elements or features. Where in the foregoing description reference has been made to integers or components having known equivalents thereof, those integers are herein incorporated as if individually set forth.

Landscapes

  • Investigating Materials By The Use Of Optical Means Adapted For Particular Applications (AREA)
  • Sorting Of Articles (AREA)

Abstract

L'invention concerne un boîtier pour un capteur configuré pour inspecter des articles transportés au-delà du boîtier par un convoyeur d'articles. Le boîtier peut comprendre un corps ayant, formé à l'intérieur de ce dernier, une fenêtre pour permettre au capteur d'inspecter des articles sur le trajet de transport, et des moyens de protection configurés pour protéger sensiblement la fenêtre d'articles projetés depuis le convoyeur d'articles. Le boîtier peut comprendre une ou plusieurs ouvertures pour permettre à un écoulement de gaz d'être projeté entre la fenêtre et le trajet de transport. Le boîtier peut être utilisé dans un dispositif d'inspection d'article avec un capteur monté à l'intérieur du boîtier, le capteur étant sensiblement au niveau du convoyeur. Le dispositif peut comprendre une caméra et une source de lumière. Le dispositif peut être constitué en tant que partie d'un système d'inspection d'article et d'un système de tri d'articles.
PCT/NZ2016/050109 2015-07-03 2016-07-01 Système d'inspection d'article à faible angle pour un convoyeur Ceased WO2017007340A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
NZ708406 2015-07-03
NZ70840615 2015-07-03

Publications (1)

Publication Number Publication Date
WO2017007340A1 true WO2017007340A1 (fr) 2017-01-12

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Application Number Title Priority Date Filing Date
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Publication number Priority date Publication date Assignee Title
EP4043111A1 (fr) * 2021-02-12 2022-08-17 Siemens Aktiengesellschaft Classification d'articles
WO2022171432A1 (fr) * 2021-02-12 2022-08-18 Siemens Aktiengesellschaft Classification d'articles
US12202012B2 (en) 2021-02-12 2025-01-21 Körber Supply Chain Logistics Gmbh Classifying items

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