WO2019177468A1

WO2019177468A1 - An article inspection system

Info

Publication number: WO2019177468A1
Application number: PCT/NZ2019/050026
Authority: WO
Inventors: Josh STROOBANT; Tauseef QUAZI
Original assignee: COMPAC TECHNOLOGIES Ltd; COMPAC Tech Ltd
Current assignee: COMPAC TECHNOLOGIES Ltd; COMPAC Tech Ltd
Priority date: 2018-03-14
Filing date: 2019-03-12
Publication date: 2019-09-19
Anticipated expiration: 2020-09-14

Abstract

An inspection apparatus for inspecting articles conveyed past the inspection apparatus by an article conveyor along a conveying path comprises an image capturing device located above a horizontal plane of the conveyor, a mirror located at a level of the horizontal plane of the conveyor and angled to provide a side view of an article on the conveyor to the image capturing device, and a housing for the mirror, and wherein the housing is or forms part of a conveyor lane-divider.

Description

AN ARTICLE INSPECTION SYSTEM

Statement of corresponding applications

This application is based on the Provisional specification filed in relation to New Zealand Patent Application Number 740733, the entire contents of which are incorporated herein by reference.

Field of Invention

The invention generally relates to the field of article conveying systems, article inspection systems and article sorting systems. More particularly, the invention relates to an article inspection system for imaging articles at a low angle.

Background to the Invention

A common type of object that is graded and sorted by a conveyor inspection system is fruit. Fruit may be sorted based on criteria such as weight, shape, colour, ripeness and any other characteristic, such as surface blemishes or defects. Conveyor systems comprise devices to measure these characteristics while the fruit is being transported. For example, 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. These existing inspection systems can detect and automatically grade fruit without requiring human intervention, and therefore offer labour efficiency gains for the processing of fruit. However, there are types of fruit defects that existing automatic inspection means detect poorly, and these defects require human involvement to detect and remove the poor quality fruit.

As fruit is conveyed along a conveying system, often at a high rate, a significant amount of debris such as dust or pieces of fruit is produced. If bits of debris stick to or build up on the lens of a camera or any part of the inspection system, the quality of the acquired images can be diminished. For example, debris on part of the optical system can appear to an automated inspection system as a blemish on a fruit, which can cause the fruit to be incorrectly processed or sorted. Furthermore, if the fruit articles collide with the imaging devices (e.g. cameras) or their enclosures, damage can be caused.

For these reasons, 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. As 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. Poor inspection of fruit can lead to incorrect processing or sorting of the fruit, resulting in unnecessary product wastage, or a higher (and more costly) labour requirement for quality control. It is therefore advantageous to reduce incorrect processing of fruit in automated sorting systems by more reliable imaging of fruit on conveying systems. It is also advantageous to reduce the spacing required between adjacent parallel conveyors (lanes) of a conveyor system and to reduce the number of cameras required to inspect articles, to reduce costs by saving on space and equipment, while providing high quality images.

Some attempts have been made to provide cameras or mirrors at the same height as fruit being conveyed in fruit conveyor sorting systems, for example as described in W02017/007340. However, such existing technology has generally not been effective because of the difficulties of keeping the cameras or mirrors and associated imaging components clean and protected. Debris deposited on a camera lens or mirror associated with a camera can result in degradation of image quality or result in erroneous registering of debris as surface blemishes or defects on the article being inspected, causing incorrect sorting of articles. There is also difficulty in illuminating fruit from a low angle.

All references, including any patents or patent applications cited in this specification are hereby incorporated by reference. No admission is made that any reference constitutes prior art. The discussion of the references states what their authors assert, and the applicants reserve the right to challenge the accuracy and pertinency of the cited documents. It will be clearly understood that, although a number of prior art publications are referred to herein, this reference does not constitute an admission that any of these documents form part of the common general knowledge in the art, in New Zealand or in any other country.

It is an object of the invention to provide an improved article inspection system that addresses one or more of the above-mentioned difficulties. Alternatively, it is an object of the invention to provide an improved mirror housing assembly and/or lane divider for use with such systems. Alternatively, it is an object of the invention to provide the public with a useful choice. Summary of the Invention

According to a first aspect of the invention, an inspection apparatus for inspecting articles conveyed past the inspection apparatus by an article conveyor along a conveying path comprises:

an image capturing device located above a horizontal plane of the conveyor, a mirror located at a level of the horizontal plane of the conveyor and angled to provide a side view of an article on the conveyor to the image capturing device,

a housing for the mirror, wherein the housing is or forms part of a conveyor lane- divider.

Preferably the housing comprises a forward surface angled to be nearer to a vertical centreline of the conveyor at a bottom edge and further away from the vertical centreline of the conveyor at a top edge, to direct articles dislodged or fallen from the conveyor back onto or towards the conveying path.

Preferably the housing comprises a forward surface and the mirror is recessed in the housing to be located further from the conveying path than the forward surface.

Preferably an angle between a vertical plane and a plane of the mirror is greater than an angle between the vertical plane and a plane of the forward surface.

Preferably the image capture device is configured to capture an image of sufficient width to include in a single image a top view of an article being conveyed by the conveyor and a side view of the article being conveyed by the conveyor provided by the mirror.

Preferably the housing comprises:

a base configured to be attached to and form part of the conveyor lane-divider, and a frame providing a window to the mirror located in the housing, wherein the frame is removable from the base to remove or provide access to the mirror. Preferably the mirror is attached to the base, removal of the frame providing access to the mirror.

Preferably the base includes a pair of spring clips to releasably retain the mirror to the base.

Preferably each said spring clip comprises a cantilever arm that extends from below a mounting surface on which the mirror is mounted to above the mounting surface, and a shoulder at a free end of the cantilever arm to bear against an outer surface of the mirror.

Preferably the length of the cantilever arm is significantly greater than a thickness of the mirror.

Alternatively, the mirror is attached to the frame to be removable from the base together with the frame.

Preferably the housing comprises a transparent barrier to cover and protect the mirror from damage or debris.

Preferably the transparent barrier is attached to the frame so that the transparent barrier is removable together with the frame as a window assembly.

Alternatively, the housing comprises a transparent barrier and the mirror comprises the transparent barrier and a mirror coating applied to a rear surface of the transparent barrier.

Preferably the frame is releasably clipped to the base by one or more releasable couplings.

Preferably the releasable coupling(s) is/are provided at or adjacent a top edge of the frame.

Preferably the frame is attached to the base in a way that prevents or reduces the likelihood of accidental removal caused by fruit colliding with the frame. Preferably the frame is attached to the base so that a direction in which the frame is removed from the base does not replicate a direction in which fruit collides with the lane-divider when dislodged from the conveyor.

Preferably the frame is pivotable from an installed position about an axis to be removed from the base. Preferably the axis is substantially parallel to the conveying direction. Preferably the axis is at or adjacent to a bottom edge of the frame.

Preferably one of the frame and the base comprises a longitudinal bead and the other one of the frame and the base comprises a corresponding channel for receiving the bead, the frame pivotable about a longitudinal axis of the bead to engage and disengage the frame to and from the base.

Preferably the housing comprises a gasket to extend around a perimeter of the mirror to form a seal between the frame and the base.

Preferably the conveyor lane-divider comprises an extruded chassis with one or more channels or projections, and the base comprises a corresponding one or more projections or channels, the projection(s) received in the channel(s) to mount the base to the chassis.

Preferably the conveyor lane-divider comprises a front panel extending along the lane-divider either side of the housing, and wherein the base has an overlapping portion at each lateral forward edge to overlap an edge portion of an adjacent said front panel.

Preferably the apparatus further comprises a top diffuse illumination source to provide diffuse lighting from above the article to illuminate the article, and wherein the mirror reflects illumination provided by the top illumination source onto the side of the article.

Preferably the apparatus comprises a lane-divider on each side of the conveyor, each lane- divider comprising a said housing and a mirror mounted to the lane-divider by the housing. Preferably the lane-divider comprises a first said housing and mirror located on a first side of the lane-divider to face the conveyor, and a second said housing and mirror located on an opposite second side of the lane-divider to face an adjacent conveyor, and wherein the first and second housings and mirrors are aligned at a longitudinal position of the lane-divider.

Preferably the lane-divider comprises a light emitting surface adjacent to the housing.

According to a second aspect of the invention, a mirror and housing assembly for a conveyor- type article inspection apparatus comprises:

a mirror, and a housing for the mirror, the housing comprising:

a base configured to be attached to and form part of a conveyor lane-divider of the inspection apparatus, and

a frame providing a window to the mirror located in the housing, wherein the frame is removable from the base to remove or provide access to the mirror.

The second aspect may comprise any one or more features associated with the first aspect described above.

According to a third aspect of the invention, a conveyor lane-divider for a conveyor-type article inspection apparatus comprises:

a mirror and a housing for the mirror, the housing comprising:

a base, and

Preferably, the lane-divider comprises an extruded chassis with one or more channels or projections, and the base comprises a corresponding one or more projections or channels, the projection(s) received in the channel(s) to mount the base to the chassis, and

a front panel extending along the lane-divider either side of the housing, each front panel comprising a one or more projections or channels corresponding with the one or more channels or projections of the extruded chassis, the projection(s) received in the channel(s) to mount the front panel to the chassis.

Preferably a front panel extends along the lane-divider either side of the housing, and wherein the base has an overlapping portion at each lateral forward edge to overlap an edge portion of an adjacent said front panel.

Additionally, the third aspect may comprise any more or more features associated with the first aspect described above.

The terms "illuminate", "illumination" and the like are used throughout this specification and claims to refer to the act of exposing something to any kind of light, including visible and non- visible light (e.g. infra-red or ultra violet light). For the purposes of this document, said terms should be considered synonymous with the terms "irradiate", "irradiation" and the like, unless the context clearly requires otherwise.

The term "camera" is used in this specification and claims to refer to a device for capturing and/or sensing light, including visible and non-visible light. It will be understood that, in any of the embodiments of the invention described, other types of sensors may be used 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.

The term "debris" is used in this specification and claims to refer to 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.

Throughout this specification and claims, the word "comprise", or variations thereof such as "comprises" or "comprising", will be understood to imply the inclusion of a stated element, integer or step, or group of elements integers or steps, but not the exclusion of any other element, integer or step, or group of elements, integers or steps.

Brief Description of the Drawings

Further aspects of the present invention will become apparent from the ensuing description which is given by way of example only and with reference to the accompanying drawings in which:

Figure 1 is a perspective view of an inspection apparatus for inspecting articles such as fruit.

Figure 2 is an end view of the inspection apparatus of Figure 1. A top illumination source is indicated schematically.

Figure 3 is a top view of the inspection apparatus of Figure 1.

Figure 4 is a perspective view of a housing and mirror assembly for a lane-divider of the apparatus of Figure 1.

Figure 5 is an exploded perspective view of the housing and mirror assembly of Figure 4.

Figure 6 is a perspective view of a base of a housing of the assembly of Figure 4.

Figure 7 is a bottom perspective view of a frame and transparent barrier assembly of the assembly of Figure 4.

Figure 8 is an exploded view of the assembly of Figure 6.

Figure 9 is a cross section on a vertical centre plane of the assembly of Figure 4.

Figure 10 is a cross section on a vertical centre plane of the assembly of Figure 4 with a frame and transparent assembly separated from a housing base. Figure 11 is a cross section of a lane-divider of the apparatus of Figure I on a vertical centre plane of a housing and mirror assembly of the lane-divider.

Figure 12 is a cross section of a lane-divider of the apparatus of Figure I on a vertical plane adjacent a housing and mirror assembly of the lane-divider.

Best Modes for carrying out the invention

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.

• The stem and calyx regions, when the axis between them lies horizontal, will often

receive insufficient illumination, resulting in a dark patch on captured images of the fruit. This makes the region difficult to grade because the quality of the effective signal, or images, is reduced.

• The combination of complex fruit geometry in the calyx and stem regions, and non-ideal illumination, often produces image artefacts such as shadows. These image artefacts then cause software that analyses the captured images of the fruit to incorrectly register a fruit defect, which can result in product wastage, or require increased labour as backup to ensure fruit is sorted correctly. These underlying principles, which can lead to poor inspection of certain defects on fruit having calyx and stem regions may also apply to other types of fruit having depressions, protrusions or other deviations from a uniform shape. Furthermore, these principles may also apply to inspection systems for articles other than fruit. For example, other articles may have regions that are difficult to illuminate and image in a similar manner to fruit. Where embodiments of the invention are described in this specification with reference to fruit, it should be understood that aspects of the invention can also be applied to article inspection, sorting and conveying systems for any suitable articles. It should also be understood that the embodiments of the invention described below may also improve inspection (for example, imaging) of articles that do not have regions that are especially difficult to illuminate or image.

Figures 1 to 3 show a fruit inspecting and conveying apparatus or system 1 comprising a conveyor 2 (only partly shown) conveying an article or piece of fruit 3 in a conveying direction 4. A typical system comprises many conveyors arranged side-by-side in parallel lanes. Figures 1 to 3 show a single lane only. Adjacent lanes are separated by a lane-divider 5. A single lane- divider 5 is shown in Figures 1 and 3, and two lane-dividers 5 are shown in Figure 2, one on each side of the conveyor 2. Each lane-divider 5 forms a lane barrier to prevent fruit that has fallen or been dislodged from the conveyor from interfering with an adjacent lane.

An image capture device 6, e.g. a camera, is provided above the conveyor. The image capture device is supported by a mounting structure or cabinet (not shown) and may be protected by a window 7 also supported by the mounting structure or cabinet. One or more cameras may be provided for each lane, for example a colour camera and one or more infrared cameras to take simultaneous exposures of the fruit. The image capture device 6 is positioned to capture a top view (plan view) image of the fruit. Preferably the image capture device is positioned directly above the conveyor 2, i.e. in line with the conveyor 2, as shown in Figures 1 to 3.

Illumination is preferably provided to deliver lighting conditions suitable for capturing high quality images. Preferably lighting is provided from above the conveyor and also from a side of the conveyor. An illumination source is preferably located at the lane-divider to provide side lighting to the fruit. A suitable side illumination arrangement provided with lane-dividers is described in WO2016/163896.

The inspection apparatus 1 comprises a mirror 102 located at the lane-divider. A housing 101 is provided to mount the mirror 102 at or to the lane divider. The housing 101 is or forms part of the lane-divider 5. A lane divider is located between adjacent parallel conveyors or to the side of an outer most conveyor. The lane-divider may act as a barrier, to direct the fruit back towards or alongside the conveyor path should the fruit fall or be dislodged from the conveyor. The housing 101 locates the mirror 102 at a height or level of a horizontal plane of the conveyor 2, e.g. a level at which the articles are supported by the conveyor. The housing is configured to locate the mirror at substantially the same vertical level as the articles carried by the conveyor. The mirror 102 is oriented at an angle to provide a side view of the fruit to the image capturing device 6 located above the conveyor 2. The mirror 102 may be angled and a camera of the image capture device 6 may be configured to capture an image of sufficient width to include in a single image a top view and a side view provided by the mirror 102. A first portion of an array of pixel provided by the image capture device is used to capture the top view and a second portion of the array of pixels is used to capture the side image. In the embodiment shown in Figure 2, a single image may incorporate multiple side views of the object. In this embodiment a mirror 102 is provided to a lane-divider 5 on one side of the conveying path and a mirror 102 is provided to a lane-divider 5 on an opposite side of the conveying path. The mirrors are angled and the camera of the image capture device 6 is configured to capture an image of sufficient width to include in a single image a top view and two opposed sides views provided by the mirrors 102. A first portion of an array of pixel provided by the image capture device is used to capture the top view, a second portion of the array of pixels is used to capture a first side image, and a third portion of the array of pixels is used to capture an opposite second side image. Images are captured sequentially, for example at a frequency of 50Hz, with each image including a top view and at least one side view. Preferably the image capture device captures an image with a height and width, wherein the width is greater than the height, the width oriented in the conveyor direction and the height perpendicular to the conveyor direction. Preferably the mirror is a first surface mirror with a high reflection efficiently across the spectrum of light being imaged, for example a first surface Protected Silver Coating Mirror with reflection efficiency above 98% from 300-1100nm (rated for visible and NIR (near infrared) applications). Preferably the system includes a single mirror in a path of light between the image capture device and the article 3, as shown in Figure 2.

In a preferred embodiment, the mirror is optimally angled to capture a side view of a piece of fruit in a range of 40mm to 120mm diameter, to capture an image of the stem or calyx area of the fruit.

As shown in Figures 1 to 3, the lane divider comprises a housing 101 and mirror 102 on both sides of the lane divider. As best shown in Figure 2, the housings and mirrors are aligned to be located at a single longitudinal position of the lane divider.

Features of the housing 101 are now described with reference to Figures 4 to 12. The housing 101 has a forward surface 103 angled to be nearer to a vertical centreline of the conveyor 2 at a bottom edge and further away from the vertical centre line of the conveyor 2 at a top edge.

The angled forward surface 103 directs fruit that has fallen or become dislodged from the conveyor back onto or towards the conveying path. The mirror 102 is recessed in the housing 101 within a window through the front surface 103, so that the mirror is located further from the conveying path than the front surface of the housing. Having the mirror recessed in the housing and therefore the lane-divider assists in preventing or reducing debris landing on the mirror. An angle A (Figure 10) between a vertical plane and a plane of the mirror is greater than an angle B between the vertical plane and a plane of the forward surface. By providing the front surface at an angle to be closer to vertical than the mirror, the top edge of the mirror is recessed further into the housing than a bottom edge of the mirror. Preferably the width of the recess (the width being aligned in the conveyor direction) is smaller than the width of the articles being conveyed to reduce the risk of mirror damage from articles leaving the conveyor.

The housing 101 has a bottom wall portion 104 that extends substantially vertically. Bottom wall 104 portion extends downwards from a bottom edge of the angled front surface 103. The vertical bottom wall portion 104 provides a vertical barrier to help prevent fruit that has fallen off the conveyor 2 from contacting the recessed mirror. The housing has a window 105 through which the mirror 102 is visible. The window is located in the angled forward surface 103 and also extends through the vertical bottom wall portion 104. As best shown in Figures 4 and 9, a lower edge 105a of the window is below a top edge 104a of the vertical bottom wall portion. The mirror 102 extends to or below the bottom edge 105a of the window 105.

The housing 101 comprises a base part or base 106 that is configured to be attached to and form part of a lane-divider 5. The mirror 102 is received in or on the base 106. In the illustrated embodiment the base 106 has locating details 107 to locate the mirror on the base.

In the embodiment shown the locating details are projections on the base, each configured to border a corner of the mirror. The base also comprises one or more clips 108 to hold the mirror in place. The illustrated embodiment has a spring clip 108 to retain the mirror at each side.

The mirror 102 is supported on a mounting surface 109 of the base. As best shown in Figure 6, the spring clip 108 comprises a cantilever arm 108a that extends from below the mounting surface to a free end above the mounting surface 108a. A shoulder 108b is provided at the free end to bear against an outer surface of the mirror 102 so that the mirror is retained between the shoulder 108b and the mounting surface 109. The spring clip has a spring arm length L (Figure 9) that is substantially greater than a thickness of the mirror, so that the spring clip is easily deflected in order to clip the mirror into place on the base, yet securely holds the mirror in place at a correct angle. The thickness of the mirror includes the thickness of a mirror coating and a substrate on which the mirror coating is applied. The distal end of the spring clip has a ramp or angled surface 108c so that pressing an edge region of the mirror against the distal end of the clip causes the clip to deflect outwards to allow the mirror to be located on the base. Once the mirror is located on the base the clip 108 returns to or towards an un-deflected configuration with the shoulder 108b bearing against the outer surface of the mirror 102. The base holds the mirror at an optimal angle for viewing the side of the fruit. The base may be an injection moulded part. A suitable material for the base is ABS. The housing 106 comprises a frame 111 movably attached to the base. The frame is removable from the base to provide access to the mirror in the housing. The illustrated embodiment also has a transparent barrier 110 to cover the mirror 102. The transparent barrier is held in place over the mirror by the frame 111. The frame 111 and transparent barrier 110 form a removable window assembly through which the mirror 102 is visible. The transparent barrier 110 and frame 111 protects the mirror from mechanical damage and debris. The transparent barrier 110 may be made from cast acrylic which has minimal transmission loses across the spectrum of light being imaged, for example a 300-1100nm wavelength band. Cast acrylic has minimal surface imperfections, to provide an unobstructed view of the mirror 102. The transparent barrier 110 is preferably mounted/attached to the frame 111. The frame may be over-moulded to the transparent barrier. In the illustrated embodiment shown in Figures 7 and 8, a pair of brackets 112 secure the transparent barrier 110 to the frame 111. Each bracket 112 is attached to the frame 111 by a fastener 114 (screw), so that the transparent barrier 110 is secured between the frame 111 and brackets 112. The frame may be an injection moulded component. A suitable material for the base is ABS. The brackets may also be injection moulded parts or may be folded/stamped from sheet metal.

In an alternative embodiment the mirror may be attached to the frame, to be removable from the base together with the frame. The mirror may be attached to the frame below the transparent barrier 110. Alternatively, the mirror may comprise the transparent barrier and a mirror coating applied to a rear surface of the transparent barrier. The mirror may be attached to the frame using a similar clip configuration using cantilever arms 108a as described with reference to Figure 6.

The frame 111 is removable from the base, to provide access to the mirror 102 and for cleaning. The frame 111 may be removed for cleaning and replaced for subsequent use. The frame 111 is adapted to be easily removed and replaced, without tools.

In the illustrated embodiment, the frame 111 is clipped to the base 106. The frame comprises two female connectors/couplings 115 and the base 106 comprises two corresponding male connectors/couplings 116 to be received by the female couplings 115 to clip the frame 111 to the base 110. Alternatively, female couplings may be provided on the base and male couplings provided on the frame. There may be a single male/female coupling pair or two or more male/female coupling pairs provided between the base and removable frame. In the illustrated embodiment the female coupling 115 comprises a pair of spaced apart springs or fingers and the corresponding male coupling 116 comprises a projection configured to be received between the fingers of the female coupling. Any other suitable clipping arrangement may be employed that provides for repeated installation and removal of the frame 111 to and from the base 110.

Preferably the frame is attached to the base in a way that prevents or reduces the likelihood of accidental removal caused by fruit colliding with the frame. Accidental removal is prevented or reduced by ensuring a direction in which the frame is removed from the base does not replicate a direction in which fruit collides with the lane-divider when dislodged from the conveyor. For example, in a preferred embodiment the frame is attached to and removed from the base by pivoting about an axis that is parallel to the conveying direction 4. When colliding with a lane barrier, a fruit predominantly travels in the conveyor direction, parallel to the pivot axis about which the frame is pivoted for removal. A force direction provided along or parallel to the pivot axis, and not around the pivot axis, is unlikely to dislodge the frame from the base of the housing. In an alternative embodiment, the frame may pivotally attach to the base about a pivot axis along or adjacent to a lateral upstream edge of the frame, or the frame may be attached to the base in a sliding engagement, sliding from an upstream side to a downstream side of the base.

In the illustrated embodiment, the releasable couplings 115, 116 are provided at or towards a top edge of the frame 111, and the frame is pivotable about an axis at or adjacent to the bottom edge of the frame. Preferably the pivot axis is nearer to a bottom of the frame, since any impact from a fruit with the frame will more likely be nearer to a bottom of the frame and so will present a small moment about the pivot axis. The bottom edge of the frame is formed as a longitudinal curved bead 117. The curved bead 117 is received in a corresponding longitudinal curved channel 118 formed in the base 106. To install the frame 111 to the base 106, the bottom edge curved bead 117 is placed into the channel 118 of the base, initially with a top of the frame positioned outwards from the base. The frame 111 is then pivoted about a longitudinal axis of the bead 117 and channel 118 to engage the coupling pairs 115, 116 at or near the top edge to secure the frame 111 to the base 106 with the transparent barrier 110 covering the mirror 102. To remove the frame 111 from the base 106 the frame is pivoted outwards from the base about the bead and channel, to disengage the couplings 115, 116. The longitudinal axis of the bead and channel is parallel to the conveying direction 4 of the conveyor 2. Once the couplings have been disengaged the frame is removed by lifting the bead 117 out of the channel 118. The channel is arranged so that the frame cannot be removed from the base in a direction perpendicular to a plane of the mirror. Preferably the bead and channel and the releasable couplings 115, 116 are arranged so that the frame must be pivoted about the longitudinal axis of the bead and channel to release the frame from the base. The bead and channel form a hinge with a hinge axis parallel to the conveying direction of the conveyor. In an alternative embodiment the base comprises the bead and the frame comprises a corresponding channel.

The illustrated embodiment also has a pair of recesses or apertures 120 in the channel 118 and the frame 111 has a corresponding pair of projections 121 to be received in the recesses 120. The projections 121 received in the recesses 120 further assist with securing the frame to the base. One recess and projection or two or more recesses and corresponding projections may be provided.

To assist with removal and installation, the frame preferably comprises one or more lever portions 119 that extend or project from the base 106 with the frame 111 installed to the base 106. To remove the frame 111 a user pulls on the one or more levers 119 to pivot the frame outwards from the top of the housing with the frame pivoting about the lower edge of the frame. In an alternative embodiment, the frame may pivotally attach to the base about a pivot axis along or adjacent to a lateral upstream edge of the frame, or the frame may be attached to the base in a sliding engagement, sliding from an upstream side to a downstream side of the base.

The housing 101 further comprises a gasket or resilient member 113 to extend around a perimeter of the mirror 102. With the frame 111 installed on the base 106 the gasket 113 is compressed between the frame 111 and the base 106 to provide a seal about the mirror 102 to prevent debris reaching the mirror below the frame 111 and transparent barrier 110. The gasket may also provide vibration damping between the frame and the base. The frame 111 has an inner perimeter wall or edge 122 configured to contact the gasket. Preferably the frame contacts the gasket fully around the mirror. The gasket may be made from food safe silicone foam tape, or other suitable material.

The housing base 106 is preferably mountable to a chassis of a lane divider 5, alongside forward-facing panels of the lane-divider 5. The lane-divider 5 preferably houses lighting that is emitted as a side lighting source through the panels of the lane-divider. The housing base 106 and panels are preferably mounted to the chassis. The chassis is preferably a longitudinal extrusion, e.g. an aluminium extrusion. Figure 11 is a cross section through the housing 101 forming part of the lane-divider 5, and Figure 12 is a cross section through the lane-divider 5 adjacent the housing 101. As shown in Figure 11, the chassis 124 has one or more channels 125 to receive corresponding projections 126 (e.g. Figure 10) on the housing. Alternatively, the housing may have one or more projections to be received in corresponding channels in the chassis. Preferably the housing is mounted to the chassis in the same way as the front panels 127 of the lane-divider 5. As shown in Figure 12, the lane-divider front panel 127 also has projections 126 received in channels 125 of the extruded chassis. The housing has an overlapping portion 128 at each lateral forward edge to overlap an edge portion of adjacent front panels 127 of the lane-divider 5. The lane-divider also has a cap 129 to cover over a top edge of the base of the housing 101. The cap 129, housing overlapping portions 128, and projections 126 received in channels 125 prevent debris being transferred from outside of the lane-divider to inside the lane-divider and housing 101, so that the mirror 102 (and any internal lane divider electronics) remains clean. In some embodiments the front panel may be a light emitting surface. For example, the lane-divider may include an internal mounted light source and the front panel 127 may form a light diffusing panel to provide a low angle diffuse light source. Alternatively, the lane divider may be 'passive', i.e. a lane divider that does not emit light.

Preferably the inspection apparatus 1 also comprises a top lighting/illumination source 30 to provide diffuse lighting from a height above the conveyor, to illuminate the top of the article for improved top image quality. The top illumination source may comprise a surface located above the conveyor and articles on the conveyor that reflects light provided by a light source located at or below the conveyor. As described above, side lighting may also be provided, for example at the lane-divider, to improve side lighting applied to the article. The location of the mirror at the lane-divider near to the conveying direction reflects illumination provided by the top lighting source onto the side of the article. Thus, the mirror 102 provides a light path from the article 3 to the image capture device, and additionally provides a light path from the top mounting light source to the article, to provide additional lighting to the side of the article. The mirror provides additional lighting to the side of the article; however, a majority of lighting is preferably provided by a top diffuse illumination source, and additionally may be provided with side lighting from the lane-divider as described above.

The present invention provides a means for providing a high-quality side view image of an article such as a piece of fruit on a conveyor. The invention provides a mirror near to the side of articles to be inspected, to allow for a top image and a side image to be captured by a single image capturing sensor. Both the side and top images, or the top and two opposed side images are captured in a single array of pixels of the image capture device. Additionally, the location of the mirror allows for a side view to be captured together with a top view in a single array of pixels with both views in focus, presenting high quality images for both the top and side views. For a preferred embodiment described herein, an aperture size of F2.8 provides for a focused top image and side image to be captured in a single pixel array, even though the light path from the image capture device to the side of the fruit is longer than the light path from the image capture device to the top of the fruit. Furthermore, the invention utilises top lighting to illuminate the side of the article. The requirement for improved side lighting or a side mounted camera is avoided, reducing cost and complexity.

The housing supports the mirror securely at an optimum angle, while allowing the mirror to be easily replaced without removing the housing from the lane-divider. The housing comprising a removable frame with transparent barrier provides mechanical protection for the delicate mirror and prevents debris landing on the mirror. The removable frame can be removed easily and quickly without tools, for cleaning and replacement. An article inspection facility may include supplementary removable frames and transparent barriers. In an equipment inspection/cleaning task, a frame and transparent barrier that has been in use may be swapped out for a clean frame and transparent barrier. The removed frame and transparent barrier may be cleaned for subsequent replacement. Thus, the present invention allows for reduced downtime required for cleaning to ensure high quality images of the side of an article.

The apparatus allows for the problematic stem and calyx areas of fruit such as apples to be captured in high quality images, even when the fruit is oriented on the conveyor with the stem and calyx in a horizontal plane.

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.

Aspects of the present invention have been described by way of example only and it should be appreciated that modifications and additions may be made thereto without departing from the scope thereof as defined in the appended claims.

Claims

Claims:

1. An inspection apparatus for inspecting articles conveyed past the inspection apparatus by an article conveyor along a conveying path, the inspection apparatus comprising:

2. An inspection apparatus as claimed in claim 1, wherein the housing comprises a forward surface angled to be nearer to a vertical centreline of the conveyor at a bottom edge and further away from the vertical centreline of the conveyor at a top edge, to direct articles dislodged or fallen from the conveyor back onto or towards the conveying path.

3. An inspection apparatus as claimed in claim 1 or 2, wherein the housing comprises a forward surface and the mirror is recessed in the housing to be located further from the conveying path than the forward surface.

4. An inspection apparatus as claimed in claim 2 or 3, wherein an angle between a vertical plane and a plane of the mirror is greater than an angle between the vertical plane and a plane of the forward surface.

5. An inspection apparatus as claimed in any one of claims 1 to 4, wherein the image capture device is configured to capture an image of sufficient width to include in a single image a top view of an article being conveyed by the conveyor and a side view of the article being conveyed by the conveyor provided by the mirror.

6. An inspection apparatus as claimed in any one of the preceding claims, wherein the housing comprises: a base configured to be attached to and form part of the conveyor lane-divider, and a frame providing a window to the mirror located in the housing, wherein the frame is removable from the base to remove or provide access to the mirror.

7. An inspection apparatus as claimed in claim 6, wherein the mirror is attached to the base, removal of the frame providing access to the mirror.

8. An inspection apparatus as claimed in claim 7, wherein the base includes a pair of spring clips to releasably retain the mirror to the base.

9. An inspection apparatus as claimed in claim 8, wherein each said spring clip comprises a cantilever arm that extends from below a mounting surface on which the mirror is mounted to above the mounting surface, and a shoulder at a free end of the cantilever arm to bear against an outer surface of the mirror.

10. An inspection apparatus as claimed in claim 9, wherein the length of the cantilever arm is significantly greater than a thickness of the mirror.

11. An inspection apparatus as claimed in claim 6, wherein the mirror is attached to the frame to be removable from the base together with the frame.

12. An inspection apparatus as claimed in any one of claims 6 to 11, wherein the housing comprises a transparent barrier to cover and protect the mirror from damage or debris.

13. An inspection apparatus as claimed in any one of claims 6 to 12, wherein the transparent barrier is attached to the frame so that the transparent barrier is removable together with the frame as a window assembly.

14. An inspection apparatus as claimed in claim 13, wherein the housing comprises a transparent barrier and the mirror comprises the transparent barrier and a mirror coating applied to a rear surface of the transparent barrier.

15. An inspection apparatus as claimed in any one of claims 6 to 14, wherein the frame is releasably clipped to the base by one or more releasable couplings.

16. An inspection apparatus as claimed in claim 15, wherein the releasable coupling(s) is/are provided at or adjacent a top edge of the frame.

17. An inspection apparatus as claimed in any one of claims 6 to 16, wherein the frame is pivotable from an installed position about an axis to be removed from the base, and preferably the axis is substantially parallel to the conveying direction, and preferably the axis is at or adjacent to a bottom edge of the frame.

18. An inspection apparatus as claimed in claim 17, wherein one of the frame and the base comprises a longitudinal bead and the other one of the frame and the base comprises a corresponding channel for receiving the bead, the frame pivotable about a longitudinal axis of the bead to engage and disengage the frame to and from the base.

19. An inspection apparatus as claimed in any one of claims 6 to 18, wherein the housing comprises a gasket to extend around a perimeter of the mirror to form a seal between the frame and the base.

20. An inspection apparatus as claimed in any one of claims 6 to 19, wherein the conveyor lane-divider comprises an extruded chassis with one or more channels or projections, and the base comprises a corresponding one or more projections or channels, the projection(s) received in the channel(s) to mount the base to the chassis.

21. An inspection apparatus as claimed in claim 20, wherein the conveyor lane-divider comprises a front panel extending along the lane-divider either side of the housing, and wherein the base has an overlapping portion at each lateral forward edge to overlap an edge portion of an adjacent said front panel.

22. An inspection apparatus as claimed in any one of claims 1 to 21, wherein the apparatus further comprises a top illumination source to provide diffuse lighting from a height above the horizontal plane of the conveyor, to illuminate a top of the article, and wherein the mirror reflects illumination provided by the top illumination source onto the side of the article.

23. An inspection apparatus as claimed in any one of claims 1 to 22, wherein the apparatus comprises a lane-divider on each side of the conveyor, each lane-divider comprising a said housing and a mirror mounted to the lane-divider by the housing.

24. An inspection apparatus as claimed in any one of claims 1 to 23, wherein the lane- divider comprises a first said housing and mirror located on a first side of the lane-divider to face the conveyor, and a second said housing and mirror located on an opposite second side of the lane-divider to face an adjacent conveyor, and wherein the first and second housings and mirrors are aligned at a longitudinal position of the lane-divider.

25. An inspection apparatus as claimed in any one of claims 1 to 24, wherein the lane- divider comprises a light emitting surface adjacent to the housing.

26. A mirror and housing assembly for a conveyor-type article inspection apparatus, comprising:

a mirror, and a housing for the mirror, the housing comprising:

27. A conveyor lane-divider for a conveyor-type article inspection apparatus, comprising: a mirror and a housing for the mirror, the housing comprising:

a base, and

28. A conveyor lane-divider as claimed in claim 27, wherein the lane-divider comprises an extruded chassis with one or more channels or projections, and the base comprises a corresponding one or more projections or channels, the projection(s) received in the channel(s) to mount the base to the chassis, and

29. A conveyor lane-divider as claimed in claim 27 or 28, comprising a front panel extending along the lane-divider either side of the housing, and wherein the base has an overlapping portion at each lateral forward edge to overlap an edge portion of an adjacent said front panel.