Device and method for optical control under diffuse illumination and observation means of crockery items or any glazed ceramic products

Abstract

In the present invention, a method and apparatus are implemented for inspecting the surfaces of ceramic tableware/pieces of ceramic crockery, said method and apparatus being characterized in that, with a single item of equipment: A—the product is illuminated by overall or zone-by-zone diffuse illumination; and B—the product is observed using one or more observation means, by causing the overall diffuse illumination or the localized diffuse illumination from at least one diffuse illumination zone adapted to make at least a selected portion of the product shiny to reflect off said product towards said one or more observation means. The invention makes it possible, with a single piece of apparatus, to show and to identify the defects, whatever they may be, using methods that are “multi-purpose” and fully effective even in critical cases, such as a combination of complex shapes, of shininess, and of white-on-white defects, unlike the prior art.

1 - 49 . (canceled)  
     
     
         50 . A method for inspecting a surface of a piece of ceramic crockery, the method comprising the steps of: 
 positioning the piece within an enclosure, the enclosure comprising: 
 a wall having an interior surface, and  
 at least one opening formed in the wall;  
   illuminating the piece by diffuse illumination using an illumination means, the illumination means comprising at least one light source disposed outside the enclosure;    delivering at least a portion of illumination from the at least one light source to the piece; and    observing at least one zone of the piece with an observation means to detect a defect in the surface of the piece,    wherein the illumination from the at least one light source is diffused by passing through the wall of the enclosure to form the diffuse illumination, and    wherein light reflected from the at least one zone of the piece passes through the at least one opening towards the observation means.    
     
     
         51 . A method for inspecting a surface of a piece of ceramic crockery, the method comprising the steps of: 
 positioning the piece within an enclosure, the enclosure comprising: 
 an interior surface,  
 at least one first opening, and  
 at least one second opening disposed below the enclosure and being separate and distinct from the at least one first opening;  
   illuminating the piece by diffuse illumination using an illumination means, the illumination means comprising at least one light source disposed outside the enclosure;    delivering at least a portion of illumination from the at least one light source to the piece; and    observing at least one zone of the piece with an observation means to detect a defect in the surface of the piece,    wherein the illumination from the at least one light source penetrates the enclosure via the at least one second opening below the enclosure,    wherein the illumination from the at least one light source is diffused by reflecting off of the interior surface of the enclosure to form the diffuse illumination, and    wherein light reflected from the at least one zone of the piece passes through the at least one first opening towards the observation means.    
     
     
         52 . A method for inspecting a surface of a piece of ceramic crockery, the method comprising the steps of: 
 positioning the piece within an enclosure, the enclosure comprising: 
 an interior surface,  
 at least one first opening, and  
 at least one second opening disposed below the enclosure and being separate and distinct from the at least one first opening;  
   illuminating the piece by diffuse illumination using an illumination means, the illumination means comprising at least one light source disposed outside the enclosure;    delivering illumination from the at least one light source towards a mirror, wherein the mirror reflects at least a portion of the illumination substantially horizontally towards at least one zone of the piece; and    observing at least one zone of the piece with an observation means to detect a defect in the surface of the piece,    wherein the illumination from the at least one light source penetrates the enclosure via the at least one second opening disposed below the enclosure,    wherein the illumination from the at least one light source is diffused by reflecting off of the interior surface of the enclosure to form the diffuse illumination, and    wherein light reflected from the at least one zone of the piece passes through the at least one first opening towards the observation means.    
     
     
         53 . The method according to  claim 50 , wherein the observing step is performed by at least one optical camera and optionally with assistance from an accessory optical system.  
     
     
         54 . The method according to  claim 50 , wherein the observation means is at least two cameras.  
     
     
         55 . The method according to  claim 50 , wherein the at least a portion of illumination from the at least one light source is reflected by a mirror in a direction that is substantially parallel to the surface of the piece.  
     
     
         56 . The method according to  claim 50 , wherein the illuminating the piece step is performed in at least two stages with a plurality of successive illumination sequences.  
     
     
         57 . The method according to  claim 56 , wherein a first stage of the illuminating the piece step is performed with an optical multiplexing means.  
     
     
         58 . The method according to  claim 50 , wherein the diffuse illumination is effected on an entirety of the piece and illuminating the at least one zone.  
     
     
         59 . The method according to  claim 50 , wherein the enclosure further comprises a floor, wherein the at least one second opening is formed in the floor of the enclosure, and wherein the at least one light source is positioned under the floor of the enclosure.  
     
     
         60 . The method according to  claim 50 , wherein the enclosure is formed from one of an opaque, translucent, and frosted material.  
     
     
         61 . The method according to  claim 60 , wherein the at least one light source is positioned under the enclosure, and wherein the enclosure partially covers the piece.  
     
     
         62 . The method according to  claim 50 , wherein the enclosure further comprises a third opening, and wherein positioning the piece within the enclosure comprises inserting the piece through the third opening.  
     
     
         63 . The method according to  claim 59 , wherein the floor of the enclosure is a color selected from the group consisting of white, clear, translucent, opaque, dark, and black.  
     
     
         64 . The method according to  claim 63 , wherein the enclosure is surrounded by a hood formed from an opaque material, and wherein an interior surface of the hood distributes the diffuse illumination homogeneously therein.  
     
     
         65 . The method according to  claim 64 , wherein at least a portion of the camera is placed inside the dome, wherein the camera is rendered optically invisible by a mask comprising at least one of a light-diffusing screen and a semi-reflective strip, and wherein the mask prevents unwanted reflections off the camera but allows light reflected from the piece to pass through to a lens of the camera.  
     
     
         66 . The method according to  claim 50 , wherein the observation means is inclined relative to the illumination means.  
     
     
         67 . The method according to  claim 62 , wherein the observation means is at least one optical camera, wherein the piece is rotated under the enclosure, and wherein the at least one camera zooms in on a portion of the piece.  
     
     
         68 . The method according to  claim 50 , wherein the delivery step is performed by a mirror.  
     
     
         69 . The method according to  claim 65 , wherein the semi-reflective strip is inserted between the camera and the dome to mask virtual images of the lens in the piece.  
     
     
         70 . The method according to  claim 50 , wherein the diffuse illumination is localized on one or more zones of the enclosure, and wherein one or more zones of the piece are observed.  
     
     
         71 . The method according to  claim 50 , wherein the at least one light source is selected from the group consisting of a lamp and a meccano-optical apparatus to illuminate at least one zone within the enclosure.  
     
     
         72 . The method according to  claim 58 , wherein the at least one zone is circular, elliptical, annular, solid, hollow, of different sizes, of uniform shapes, of non-uniform shapes, of uniform dimensions, or of non-uniform dimensions.  
     
     
         73 . The method according to  claim 58 , wherein a plurality of zones is illuminated.  
     
     
         74 . The method according to  claim 50 , further comprising a step of rotating the piece to cover an entire surface of the piece.  
     
     
         75 . The method according to  claim 70 , further comprising projecting an image on the one or more zones of the piece, wherein the image is selected from a grid of Cartesian co-ordinates, polar co-ordinates, a pattern plate, an array of points, or an array of lines, and wherein optical and shape defects of the piece show up as a distortion in the projected image reflected from the surface of the piece.  
     
     
         76 . The method according to  claim 50 , wherein the at least one light source is electrically powered by a three-phase network between phase and neutral, and wherein the at least one light source is uniformly distributed over each electrical phase.  
     
     
         77 . The method according to  claim 75 , wherein the illumination of the at least one light source forms at least one diffuse intense light zone on the interior surface of the enclosure, wherein the at least one diffuse intense light zone is reflected onto the surface of the piece to form a virtual image, and wherein the light reflected from the surface of the piece toward the observation means corresponds to the virtual image.  
     
     
         78 . The method according to  claim 77 , wherein the one or more zones is a plurality of light zones of different shapes and dimensions, and wherein the piece is optionally rotated.  
     
     
         79 . The method according to  claim 58 , wherein the enclosure is a plurality of domes, wherein observing the piece occurs sequentially within the plurality of domes, wherein the piece is fed into each of the plurality of domes, the piece is positioned within each of the plurality of domes, one or more faces of the piece is inspected within each of the plurality of domes, and the piece is removed from each of the plurality of domes, and wherein a mechanism automatically feeds, positions, and removes the piece from each of the plurality of domes.  
     
     
         80 . The method according to  claim 79 , wherein the piece is examined without zooming under at least one of the plurality of domes, and at least one zone of the piece is examined with zooming with or without rotation of the piece in another of the plurality of domes.  
     
     
         81 . The method according to  claim 50 , wherein the piece is a glazed ceramic product, and wherein observing the piece comprises computer processing in two stages, wherein the first stage comprises scanning a first image of a central portion of the glazed ceramic product from left to right and from top to bottom of the image, and the second stage comprises scanning a second image of a peripheral portion of the glazed ceramic product, from left to right and from bottom to top of the image, wherein each line of the image corresponds to a portion of the peripheral portion having a constant radius relative to the center of the piece.  
     
     
         82 . The method according to  claim 58 , further comprising zooming in on a first zone of the at least one zone of the piece and examining the first zone only.  
     
     
         83 . The method according to  claim 50 , wherein the observing step further comprises viewing an image of one or more portions of the piece that are not directly visible by the observation means.  
     
     
         84 . The method according to  claim 57 , wherein the optical multiplexing means comprises illuminations of different colors and corresponding filters.  
     
     
         85 . The method according to  claim 50 , wherein the enclosure totally covers the piece.  
     
     
         86 . The method according to  claim 50 , wherein the enclosure is a dome and wherein the dome is spherical, hemispherical, substantially spherical, substantially hemispherical, spherical oblate, hemispherical oblate, spherical deformed into a cone, hemispherical deformed into a cone, ellipsoid, deformed ellipsoid, cylindrical, or rectangular-block shaped.  
     
     
         87 . The method according to  claim 50 , wherein the observation means comprises at least one camera.  
     
     
         88 . The method according to  claim 87 , wherein the enclosure is a dome, and wherein the camera is placed on a pole of the dome and is directed towards a face of the piece through the at least one first opening.  
     
     
         89 . The method according to  claim 50 , wherein the enclosure is inclined relative to the piece.  
     
     
         90 . The method according to  claim 50 , wherein the piece is inclined relative to the enclosure.  
     
     
         91 . The method according to  claim 73 , wherein the plurality of zones comprises a plurality of circular zones combined on different portions of the piece.  
     
     
         92 . The method according to  claim 73 , wherein the plurality of zones comprise two 180° zones or three 120° zones, or one or more circular zones combined with one or more rings or square zones.  
     
     
         93 . The method according to  claim 80 , wherein one of the plurality of domes is used to inspect the piece under diffuse illumination, and wherein a second dome of the plurality of domes is used to inspect the piece under diffuse illumination zone-by-zone.  
     
     
         94 . The method according to  claim 93 , wherein the plurality of domes includes accessory equipment comprising mirrors, dimensional or geometrical measurement means, or cameras equipped with lenses or filters.  
     
     
         95 . The method according to  claim 94 , wherein the illumination means comprises a laser beam.  
     
     
         96 . A method according to  claim 81 , wherein the glazed ceramic product is circularly symmetrical.  
     
     
         97 . The method according to  claim 81 , wherein the central portion of the glazed ceramic product is a basin or bottom of a plate.  
     
     
         98 . The method according to  claim 81 , further comprising accessory interpolation and re-adjustment tools for interpolation and re-adjustment of the peripheral portion of the glazed ceramic product.  
     
     
         99 . The method according to  claim 50 , wherein the piece comprises ceramic tableware, plates, cups, saucers, or serving dishes.