Classifications

• • 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
  • G01N21/88—Investigating the presence of flaws or contamination
  • G01N21/95—Investigating the presence of flaws or contamination characterised by the material or shape of the object to be examined
  • G01N21/958—Inspecting transparent materials or objects, e.g. windscreens
• • 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
  • G01N21/88—Investigating the presence of flaws or contamination
  • G01N21/89—Investigating the presence of flaws or contamination in moving material, e.g. running paper or textiles
  • G01N21/892—Investigating the presence of flaws or contamination in moving material, e.g. running paper or textiles characterised by the flaw, defect or object feature examined
  • G01N21/896—Optical defects in or on transparent materials, e.g. distortion, surface flaws in conveyed flat sheet or rod
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
  • H04N23/00—Cameras or camera modules comprising electronic image sensors; Control thereof
  • H04N23/70—Circuitry for compensating brightness variation in the scene
  • H04N23/74—Circuitry for compensating brightness variation in the scene by influencing the scene brightness using illuminating means

Definitions

• the invention relates to an analysis device for detecting, measuring and identifying point defects on the surface or in the mass of a transparent substrate, i.e. at least partially transparent.
• This device concerns all transparent products with point defects that alter the appearance of this product vis-à-vis the user.
• this device is adapted to the appearance defects present in glazings whatever their destination.
• the characterization of faults must be done most often on an industrial line, on a moving substrate and in an exhaustive manner that is to say by controlling 100% of the products. In addition, this control must be done preferentially during the production of the basic product, the detection of defects in appearance on finished product (automotive glazing, double glazing, ...) forcing to reject a product already developed and expensive.
• the identification of defects is the most complex challenge given the speed of displacement of the substrate during an online inspection, the reduced size of defects (often millimeter) and the presence of fictitious defects that must be ignored by the detection device. Moreover, the nature of the defect helps to define its gravity. The quality of this identification requires to have a maximum of information on the optical and dimensional properties of the defect.
• the defects of appearance are often formed by point defects, located on the surface (higher or lower) or in the mass of the substrate.
• defects of appearance are usually characterized according to a typology based on their physical characteristics (bubbles, solid mineral inclusions, scratches, metallic solid inclusions, ).
• a sensitivity level ranging from 0 to 1 for example.
• a metallic inclusion will be classified among the absorbing defects of sensitivity level 1 because this defect fully absorbs the light.
• the other properties will be of level 0 because this type of defect is, a priori, neither diffusing, deforming, nor polarizing, nor colored, ...
• a stripe could be classified as absorbing with a weak sensitivity and diffusing with a sensitivity strong, its sensitivity to other properties being zero.
• a gaseous inclusion is both absorbent and diffusing with a medium sensitivity and deforming at its periphery with a high sensitivity.
• each type of appearance defect can be associated with at least one optical property whose use will allow optimal detection of the defect.
• These lighting modes can be implemented in transmission mode (source and detector placed on either side of the substrate) or in reflection mode (source and detector on the same side of the substrate).
• WO-A-2007/045437 describes a system of this type.
• the discontinuous control (control with stop of the object to be checked) necessarily uses a matrix camera and does not allow the use of several types of lighting. Moreover, it is very slow and is not suitable for exhaustive quality control.
• a linear camera is composed of a sensor formed of a single line of pixels.
• a matrix camera is composed of a sensor that forms a matrix of pixels.
• the ScreenScan-Final system from ISRA Vision for the control of appearance defects on the automotive glass production line.
• This device is equipped with several lighting transmission and reflection, each of the lights being associated with a series of linear cameras.
• This device equipped with three measurement channels, is expensive, complex, cumbersome and only controls a car glazing every 20 seconds or so. It is not adaptable to control on glass ribbon in continuous scrolling.
• This machine which can be equipped with several lights, detects and identifies (partially) the appearance defects in the glass.
• this system typically uses a set of five linear cameras to cover the width of the glass ribbon. The severity of the defects is only defined from the dimension of the defects.
• US-A-2007/0263206 illustrates a device in which a substrate is simultaneously illuminated by a "dark field” lighting and bright field lighting.
• An object of the invention is to provide a simple and inexpensive device for detection, measurement (in terms of gravity) and identification of point defects of a transparent substrate in continuous scrolling with a good level of performance.
• the subject of the invention is a device for analyzing the optical quality of one or more at least partially transparent substrate (s), for example a glass ribbon, moving in relation to the device, comprising:
• a lighting system for forming an image in transmission through the substrate and / or in reflection on the substrate;
• a control unit comprising a memory on which are stored control programs for the acquisition of the images by the camera,
• the lighting system is able to simultaneously produce different type of lighting in disjoint lighting zones through which the or each substrate is intended to scroll;
• the camera is matrix and able to acquire an image of several lines of pixels, the device being configured so that the camera is able to simultaneously acquire an image of several groups of adjacent lines of pixels respectively corresponding to said disjoint zones,
• Said control programs are able to control the camera for different acquisitions synchronized with the speed of travel of the substrate (s) so that at least one and the same fixed point of the substrate is subject to an acquisition of image in a first of said groups of pixel lines and at least in a second group distinct from the first.
• the device comprises one or more of the following characteristics, taken separately or in any technically possible combination:
• the synchronization is such that the entire length to be analyzed of the substrate (s) is analyzed with each of the different types of lighting;
• the different groups of adjacent lines of pixels have an identical number of lines
• At least one of the groups of adjacent pixel lines has at least 5 adjacent lines of pixels, for example at least 10 pixels, for example at least 50 pixels;
• said groups of adjacent rows of pixels are spaced apart in pairs and have at least 5 adjacent lines of pixels, for example at least 10 pixels, for example at least 50 pixels;
• the device is configured so that at least several of said different types of lighting of the disjointed areas are transmission lighting or for at least several of said different types of illumination of the disjointed areas to be reflective lighting;
• the device is configured so that at least one of said different types of illumination is a transmission illumination of one of the disjunct zones and for at least one of said different types of illumination to be illuminated by reflection of another disjointed areas;
• the device is configured so that several of said different types of illumination of the disjunct zones are transmission lights of several of the disjoint zones and for several of said different types of lighting to be reflective lighting of several other disjoint zones;
• the lighting system and the camera are in fixed operation between them and the substrate or the transparent substrate (s) movable (s) relative to them;
• the device comprises a unit for processing the images acquired by the camera, the processing unit including a computer and a memory on which are stored processing programs that can be implemented by the computer, said programs being able to provide quantities representative of the optical quality of the substrate (s) analyzed;
• At least one of the disjunctive lighting zones has an oblong contour with a length / width ratio of> 10, preferably each lighting zone.
• the invention also relates to a method for analyzing the optical quality of one or more at least partially transparent substrate (s), for example a scrolling glass ribbon, comprising:
• a lighting system for forming an image in transmission through the substrate and / or in reflection on the substrate;
• the lighting system simultaneously produces different types of lighting in disjoint lighting areas through which the substrate (s) scroll (s);
• the acquisition is carried out on several lines of pixels simultaneously for several groups of adjacent lines of pixels respectively corresponding to said disjoint lighting zones,
• the different acquisitions are synchronized with the speed of travel of the substrate (s) so that at least one and the same fixed point of the substrate is the subject of image acquisition in a first of said groups of lines of pixels and at least in a second group distinct from the first.
• FIG. 1 shows a schematic sectional view of an analysis device according to the invention with a matrix camera and two lighting boxes, one in transmission, the other in reflection;
• FIG. 2 represents a view from above of a scrolling glass ribbon on which are visible, in the dashed zone corresponding to the field of the camera, three distinct zones of illumination produced by a lighting box: a zone test pattern lighting (strip lighting in the figure), a bright field direct lighting area, and a dark background indirect lighting area;
• FIG. 3 is a view similar to FIG. 1, illustrating in more detail a lighting box adapted to produce the lighting zones visible in FIG. 2 with illumination of several adjacent rows of LEDs, with a first row covered with a pattern for producing a pattern-type illumination, and a fourth row "off" or covered with an opaque mask to produce an indirect illumination area on the moving substrate by LED illumination of the adjacent rows;
• FIG. 4 represents a schematic view of an image captured by the matrix camera showing the positioning of the various lights in the plane of the camera receiver in the case, for example, of FIG. 1, where two boxes are present and illuminate areas. disjoined from the first zones; and
• FIG. 1 illustrates a device 1 for analyzing point defects of a float glass ribbon 2 (ie an at least partially transparent substrate) running continuously with respect to the device 1.
• This device 1 comprises, on either side of the substrate 2, two lighting housings 4, 6, one in transmission and the other in reflection.
• Each casing 4, 6 simultaneously illuminates different zones 8A, 8B, 8C, 10A, 10B, 10C (FIGS. 2 and 4) called "lighting", all disjoint, and through which the substrate 2 passes.
• these zones 8A, 8B, 8C, 10A, 10B, 10C correspond to subdivisions of the scroll plane of the ribbon 2.
• the images formed by these two housings 4, 6 on the substrate 2 are acquired by means of a single matrix camera 12. It is, in FIG. 1, disposed on the side of the reflection lighting box 4 (ie on the opposite side transmission lighting box 6).
• the camera 12 is controlled by a control unit 14.
• the images acquired by the camera 12 are then processed by a processing unit 16 to provide values representative of the number, size and type of defects analyzed.
• the acquisition of the images by the camera 12 is performed so that the substrate 2 can be analyzed over its entire surface with all types of lighting.
• the pixels of the camera 12 are divided into different groups of adjacent lines of pixels (transverse to the scroll of the substrate 2). Each group is associated with a corresponding area illuminated according to a particular type of lighting.
• the acquisition is synchronized so that the entire substrate 2 is analyzed. That is, if the groups consist of n adjacent lines with a resolution ⁇ millimeters per line in the plane of a substrate moving at the speed v, the acquisition interval will be equal to n. ⁇ / v.
• Groups do not necessarily have the same number of pixel lines, though this is preferred. And the acquisition is not necessarily carried out so as to cover the entire analyzed substrate 2 (as illustrated by way of example in FIG. 2), even if this is also preferred (ie by providing a camera field and a sufficiently wide lighting).
• the acquisition is synchronized so that at least one and the same fixed point of the substrate 2 is subject to image acquisition in a first of said groups of pixel lines and at least one in a second group distinct from the first.
• the entire surface of the substrate 2 that one wishes to analyze is the subject of an image acquisition successively in each of the groups of pixel lines associated with the different lights 8A, 8B, 8C, 10A, 10B, 10C.
• the camera 12 and the lights 8A, 8B, 8C, 10A, 10B, 10C may be arranged for different image acquisitions, all of which correspond to the substrate 2 seen in transmission, all to the substrate 2 seen in reflection or all the same. in reflection and transmission. There is no particular limitation on this point. An analysis both in transmission and in reflection is preferred.
• the illumination system is configured to illuminate differently distinct (i.e. disjoint) areas 8A, 8B, 8C, 10A, 10B, 10C in which (i.e. "through” which) the substrate 2 scrolls.
• lighting that reveals the defects differently and requires different treatments or analyzes.
• the object of the analysis (namely in the example a glass ribbon) is alternatively a succession of glass sheets or separate windows in scrolling. What is more, it is not necessarily glass, but for example an alternative plastic substrates.
• the substrate (s) are, in general, at least partially transparent (s). Full transparency is not required.
• the invention relates to a device 1 for analyzing the optical quality of one or more substrate (s) 2 at least partially transparent (s) in continuous scrolling, for example a ribbon of glass, comprising:
• a control unit 14 comprising a memory 15 on which are stored control programs for the acquisition of the images by the camera 12,
• the lighting system 4, 6 simultaneously produces different types of lighting in disjoint lighting zones 8A, 8B, 8C, 10A, 10B, 10C through which the or each substrate 2 is intended to scroll;
• the camera 12 is matrix and capable of acquiring an image of several lines of pixels (transverse to the scrolling of the substrate (s) 2), the device 1 being configured so that the camera 12 is able to simultaneously acquire an image several groups of adjacent lines of pixels respectively corresponding to said disjoint areas 8A, 8B, 8C, 10A, 10B, 10C, and wherein
• control programs are able to control the camera for different acquisitions synchronized with the speed of travel of the substrate (s) 2 so that at least one and the same fixed point of the substrate 2 is subject to an acquisition of image in a first one of said groups of pixel lines and at least in a second group distinct from the first.
• fixed point means a fixed point on the substrate 2, i.e. relative to the substrate 2.
• the device 1 include several cameras.
• the disjoint illumination zones 8A, 8B, 8C, 10A, 10B, 10C have a very elongated oblong contour (ie with a length / width ratio> 10) in the direction transversal to the running of the analyzed substrate, in particular to reduce their bulk (Ie as illustrated in Figures 2 and 4).
• one of these lights is formed of a pattern of longitudinal lines (parallel to the direction of travel) spaced transversely over the entire width of the substrate 2, as illustrated in FIG. 2, and as described in FIG. the patent application WO-A-201 1/121219 of the applicant.
• This pattern is indeed particularly suitable and effective for a partial acquisition by groups of pixel lines because it allows to easily concatenate the acquired images.
• FIG. 2 illustrates various possible illuminations in the disjoint zones 8A, 8B, 8C. These lights are made by means of a single oblong housing 4; 6, in which light sources (eg LEDs) illuminate the moving substrate 2 so as to produce different lightings in three distinct zones 8A, 8B, 8C, (ie disjoint).
• light sources eg LEDs
• the first lighting zone 8A is illuminated with a pattern of longitudinal lines as described above.
• the second lighting zone 8B is illuminated in direct light illumination. e. bright field type.
• the third lighting zone 8C is illuminated according to an indirect lighting with a dark background, i.e. of "dark field” type.
• each lighting is of any suitable type. More generally still, the lighting system is of any suitable type.
• the lighting housing 4 (here in reflection in Figure 3) comprises for example an oblong plate 18 of a white diffusing material behind which is placed a linear lighting source 20 fluorescent tubes type or, more advantageously, of the light-emitting diode (LED) type which ensures a level of illumination of the diffusing plate 18 sufficiently intense to ensure correct shooting with the aid of the camera 12.
• a linear lighting source 20 fluorescent tubes type or, more advantageously, of the light-emitting diode (LED) type which ensures a level of illumination of the diffusing plate 18 sufficiently intense to ensure correct shooting with the aid of the camera 12.
• the use of LEDs allows to modulate the intensity of this illumination by varying the supply voltage across the LEDs and / or by installing several rows of LEDs side by side that will be supplied on demand.
• the use of LEDs also makes it possible to work in colored light, that is to say to choose LEDs emitting in a chosen spectral band in order to optimize the detection of colored type defects. This makes it easy and inexpensive to obtain a diffusing light
• a regular pattern 22 consisting of an alternating succession of light and dark lines, placed parallel or perpendicular to the sense of scrolling of the substrate, to form the first lighting, called the test pattern.
• the first lighting is dedicated to the detection of deforming defects, the second, of the "bhghtfield" type for the detection of absorbing defects.
• the third illumination is, for example, also formed by screen printing or printing on the same diffusing panel 18 of a second pattern 24 constituted by a black strip which, together with the adjacent bright light base, will constitute indirect lighting (ie "dark field” ).
• a float lighting unit measures, for example, 3500 mm by 200 mm.
• This lighting box is for example used in transmission.
• the optical field covered by a matrix camera is typically 700 mm by 500 mm.
• the matrix camera 12 then observes in its optical field the reflection lighting box 4 and the transmission lighting box 6, each type of lighting occupying part of the field of the image acquired by the camera.
• the lighting box 6 used in transmission is for example the same as the housing described above illustrated in Figure 2.
• the lighting boxes will be placed sufficiently close to the substrate, the light level of the lighting boxes will be increased and the opening of the objective will be judiciously chosen to benefit from a depth of field sufficiently large to fulfill these conditions.
• Transmission lighting housings 6 and reflection 4 will be placed almost symmetrically with respect to the substrate 2 running so that the same camera 12 clearly perceives the two lighting boxes 4, 6.
• a lighting box 4 may be sized to fit the field of a single matrix camera 12 or to cover the optical field corresponding to several matrix cameras 12, in the case of an analysis of a product of great width.
• the camera 12 is connected to a processing unit 16 of the images acquired, for the processing of the images requiring a, such as the images produced by a test pattern and a darkfield lighting type.
• Brightfield lighting does not necessarily require computer processing and can be analyzed visually.
• the processing unit 16 includes a computer and a memory 17 on which are stored processing programs that can be implemented by the computer.
• the programs are capable of providing quantities representative of the optical quality of the substrate (s) 2 analyzed (s) from the images acquired.
• FIGS 5 to 12 illustrate images provided by device 1 for four different glass samples.
• the first sample (FIGS. 5 and 6) was analyzed with "bright field” illumination (FIG. 5) in transmission and transmission target illumination (FIG. 6), and highlights the detection of an absorbing defect.
• the second sample ( Figures 7 and 8) has a deforming defect, much more visible with the lighting ( Figure 8) than with bright field lighting ( Figure 7).
• the third sample (FIGS. 9 and 10) has a scattering defect, visible in "dark field” (FIG. 10) but not very visible in bright field (FIG. 9), and the fourth (FIGS. 11 and 12) a metallic inclusion, appearing particularly with the bright field (Figure 1 1) but not with a dark field light ( Figure 12).
• the resolution of the camera 12 in the direction of travel is 0.5 mm per line of pixels, it is possible to acquire in a single shot a group of 100 adjacent lines for example, which corresponds to a length of 50 mm of the substrate 2 scrolling.
• the information contained in these 100 lines of pixels will be transferred to a processing unit 16 while a new acquisition will be triggered on the next 50 mm of substrate 2.
• the synchronization of the acquisition with the speed of travel of the substrate 2 makes it possible to observe the entire substrate 2 in the direction of travel, ie a coverage error of the substrate 2, ideally 0%.

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• Analytical Chemistry (AREA)
• General Health & Medical Sciences (AREA)
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• Life Sciences & Earth Sciences (AREA)
• Physics & Mathematics (AREA)
• Biochemistry (AREA)
• Engineering & Computer Science (AREA)
• Textile Engineering (AREA)
• Multimedia (AREA)
• Signal Processing (AREA)
• Investigating Materials By The Use Of Optical Means Adapted For Particular Applications (AREA)
• Circuit Arrangement For Electric Light Sources In General (AREA)

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• 2011
  • 2011-12-02 FR FR1161114A patent/FR2983583B1/fr not_active Expired - Fee Related
• 2012
  • 2012-11-28 KR KR1020147017689A patent/KR20140096158A/ko not_active Application Discontinuation
  • 2012-11-28 CN CN201280068813.3A patent/CN104067110B/zh not_active Expired - Fee Related
  • 2012-11-28 DE DE202012013683.6U patent/DE202012013683U1/de not_active Expired - Lifetime
  • 2012-11-28 EP EP12806588.5A patent/EP2786129A1/fr not_active Ceased
  • 2012-11-28 CA CA2859598A patent/CA2859598A1/fr not_active Abandoned
  • 2012-11-28 US US14/370,568 patent/US20140368634A1/en not_active Abandoned
  • 2012-11-28 WO PCT/FR2012/052740 patent/WO2013098497A1/fr active Application Filing
  • 2012-11-28 IN IN4838CHN2014 patent/IN2014CN04838A/en unknown
  • 2012-11-28 EA EA201491082A patent/EA201491082A8/ru unknown

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