MXPA06008334A - Optical inspection for container lean - Google Patents

Abstract

Apparatus for inspecting lean of a container (34) includes a light source (50) positioned beneath a container (34) for directing light energy (60) onto the container bottom (62) as the container is held in position and rotated around an axis (A). A light sensor (54) positioned beneath the container (34) receives portions of the light energy from the source (50) reflected from the container bottom (62). An information processor (56) is coupled to the light sensor (54) for determining, as a combined function of the reflected light energy and container rotation, departure of the container bottom (62) from a plane perpendicular to the axis (A). The container (34) preferably is held in position and rotated around an axis by a drive roller (24) that urges the container (34) against axially spaced backup rollers (26, 28) so as to define an average axis of rotation as a suction of the geometry of the container (34) and spacing between the backup rollers (26, 28).

Description

JP. KE KG, KP, KR, KZ. LC. LK, LR, LS. LT. LU LV, MA, LV. MA. MD. MG. MK, MN. MW, MX, MZ NA, NI, NO, NZ MD. MG. MK. MN. MW, MX, MZ NA. NI, NO, NZ OM, OM. PG, PH. PL. PT. RO, RU, SC. SD, SE, SG, SK, SL. SM, PG. PU, PL. PT. RO. RU, SC. SD, SE. SG, SK. SL. YE. SY, SY. TJ, TM. TN, TR, TT, TZ UA. UG, UZ, VC. VN YU, ZA, TJ, TM, TN, TR, TI T¿. UA, UG, UZ VC. VN YU, / 'A, ZM. ZW, ARIPO palent (BW, GH, GM, KE, LS, MW, MZ, ZM, ZW,? RIPO patent (BW. GH, GM, KE, LS, MW, MZ, N ?, SD, SL SZ TZ. UG, ZM, ZW), Eurasian palent (? M, NA, SD, SL, SZ, TZ, UG, ZM, ZW), Eurasian patent (AM, AZ, BY, KG.KZ, MD, RU, TJ, TM ), European patent (AT. AZ BY, KG. KZ, MD, UK, TJ. TM), European patent (AT, BE. BG. CH. CY, CZ. DE. DK, EE, ES, FR. FR, GB, GR, BE, BG, CH, CY, CZ DE, DK, USA, FR, FR, GB, GR, HU, E, IS, T, LT, LU, MC, NL, PL, PT RO, SE, SK, I1U, 1E, 1S, LT, LU, MC, NL, PL, PT, RO, SE, SI, SK, TR) OAP1 patent (BF, BJ, CF, CG CL, CM, GA, GN, GQ, TR, OAP1, Palent, BF, CE, CG, Cl, CM, GA, GN, GQ, GW, ML, MR, SN, TD, TG, GW, ML, MR, NE, SN, TD, TG) as to the applicant's entitlement to claim the priority of the Published: earlier application (Rule 4 7 (iii)) for thefollowing designation - with intemational search repon nalions AE,? G. ? L AM,? T. ?OR. ? Z. B ?. BB. BG. BR. BW, BY. BZ AC. CU, CN, CO. CR. CU. CZ DE. DK, DM, DZ, For two-letter codes and other abbreviations, refer to the "GuidEC., EG, ES, Fl, GB, GD, GE, GH, GM, HR, HU.ID, ance Notes on Codes and Abbrevialions "appearing at the begin-IL. IN. 1S. JP. KE, KG, KP. KR KZ LC, LK, LR, LS, LT. LU, nm 'g ofeach regular issue oflhe PCT Guzgile, OPTICAL INSPECTION OF THE TILT INCLINATION Field of the Invention The present invention relates generally to the inspection of articles such as glass containers, and more particularly to an optical inspection apparatus and method for inspecting the tilt of the container and other aspects of the support surface of the container. BACKGROUND OF THE INVENTION In the manufacture of glassware, such as glassware, several anomalies and variations may occur that affect the commercial acceptability of the containers. These anomalies, called "commercial variations", can involve one of numerous attributes of the container. For example, commercial variations may include the dimensional characteristics of the container in the bottom or support surface of the container, in the finish of the container, or in the sealing surface of the container, these may also include variations such as crystalline inclusions. or checks within the finish, the side wall or the bottom of the container. The practice of molding marks on each container that are indicative of the mold of origin of the container for inspection and quality control purposes is conventional. Therefore, it is often useful to provide inspection equipment capable of inspecting Ref.174435 containers for commercial variations, mold marks or other characteristics that guarantee inspection. The term "inspection" is used in its broadest sense to encompass any optical, electro-optical, mechanical or electrical observation or coupling with the container to measure or determine a potentially variable characteristic, including but not necessarily limited to molding codes and commercial variations. An example of an inspection apparatus is shown in U.S. Pat. No ^ 3,313,409, which describes an apparatus for inspecting glass containers in which a wheel with triangular teeth conveys the containers in sequence through a series of inspection stations. At one of the inspection stations, the inclination of the container is inspected by contacting the support surface on the base of the container with a pair of diametrically opposed rollers. As described in U.S. Pat. 4,433,785, the rollers are coupled to linear variable differential transformers (LVDTs) to provide signals when the container is rotated. These signals are processed to indicate the deviation of the support surface from a plane and / or the deviation from the perpendicularity with respect to the axis of rotation. Another apparatus for transporting containers through a series of inspection stations is described in the U.S. patent. 6.5.81,751. EP 1118854A (corresponding to US 6,256,095) describes an optical system for inspecting the sealing surface of a container, including the measurement of the unevenness in the sealing surface as a function of the light energy reflected from the sealing surface when the container is rotated around of an axis. Although the inspection apparatus described in the patents noted above, and assigned to the assignee thereof, has enjoyed substantial commercial success, desirable improvements remain. The rollers are in contact with the bottom of the container and are subjected to mechanical wear and inaccuracy. The sizes of the rollers can limit the sizes of the containers with which they can be used, and can affect the size (resolution) of the variations that can be detected.

It is therefore a general object of the present invention to provide an apparatus and method for inspecting the containers that overcome and resolve the deficiencies mentioned above in the art, and which can be used to inspect the bottom or the supporting surface of the container. Brief Description of the Invention The present invention includes a number of aspects, which may be implemented separately from or, more preferably, in combination with each other. The apparatus for inspecting the inclination of a container according to an aspect of the present invention includes a light source placed under a container for directing the light energy on the supporting surface of the container when the container is held in position and rotated around an axis. A light sensor placed below the vessel receives portions of the light energy from the source reflected from the container support surface. An information processor is coupled to the light sensor to determine, as a combined function of the reflected light energy and the rotation of the container, the deviation of the support surface of the container from a plane perpendicular to the axis. The container is preferably held in position and rotated about an axis by a drive roller that pushes the container against the axially spaced backing rolls to define an average axis of rotation as a function of the geometry of the container and the spacing between the rolls. backup. In the preferred embodiment, a pair of sensors / light source are positioned on the diametrically opposite sides of the container support surface, and measurements are made as a function of a comparison of the sensor outputs. This preferred configuration makes the measurement independent of the axial movement of the container. In accordance with one aspect of the method of the present invention, a container support surface is inspected in accordance with the following steps: (a) providing a light source that is generally turned towards the support surface, (b) providing a sensor of the light that is generally turned toward the support surface, (c) rotating the container around its axis while holding it in a vertical position, (d) causing the light source to emit light that reflects from the support surface, (e) causing the light sensor to register the position at which the reflected light hits the light sensor, and (f) analyzing the support surface from the position data. obtained when the container rotates. According to another aspect of the method of the present invention, the amount of data processed during the optical inspection of a container support surface can be reduced. This method includes the following steps: (a) providing an optical inspection apparatus having a light source, a light sensor, a pre-processor, and a primary processor, (b) causing the light source to reflect the light from the support surface, (c) causing the light sensor to record the position of the reflected light in a first interval, (d) causing the pre-processor to scan the recorded position data of step (c) in a second interval, wherein the second interval is greater than the first interval, and (e) causing the primary processor to analyze the support surface from the scanned data of step (d). According to another aspect of the method of the present invention, the support surface of a container can be analyzed by optical inspection. This method includes the steps of: (a) providing a first optical probe for inspecting a first point on a support surface, (b) providing a second optical probe for inspecting a second point on the support surface, (c) causing the first and second optical probes to reflect the light completely from the support surface and record the relevant data for the reflections, (d) using a sinusoidal expression representative of the relative positions of the first and second points, wherein the expression has at least one variable, (e) use at least one least squares adjustment technique to solve the variable, and (f) use the variable to analyze the support surface. Brief Description of the Figures. The invention, together with the objects, features and additional advantages thereof, will be better understood from the following description, the appended claims and the attached figures, in which: Figure 1 is a diagram schematic an inspection station using an embodiment of the optical inspection apparatus of the present invention; Figure 2A and Figure 2B are more detailed schematic diagrams of the optical inspection apparatus of Figure 1, Figure 2B is taken from the direction 2B in Figure 2A; Figure 3 is a schematic perspective view of the inspection apparatus of Figure 1; Figure 4A, Figure 4B, Figure 4C, and Figure 4D belong to the optical inspection of a grooved support surface; Figure 5 is a graphical representation of the data in Figure 4D; Figure 6 is a table illustrating a method of compressing the data from the information collected by an optical inspection device; Figure 7 is a graphic representation of the compressed data of Figure 6; Figure 8 shows a view of the container corresponding to a method of analyzing the support surface using at least one least squares adjustment technique; and Figure 9A and Figure 9B are schematic diagrams illustrating the effect of the geometry of the container on the average axis of rotation. Detailed Description of the Invention • The optical inspection apparatus and method of the present invention can be used to inspect one of any number of types of containers for different criteria, but they are particularly well suited for inspecting the bottom or "supporting surface" of the invention. glass containers to check container inclination - The term "support surface" is used in its broadest sense to encompass all lower axial surfaces or the bottom of the container, including, but not limited to, surfaces of support that are flat, smooth, grained and / or fluted, as well as those surfaces that have circumferentially extending seating rings, where the rings are smooth, grained and / or scored An example of an indexing and inspection machine which can use the apparatus and optical inspection method of the present invention is shown in U.S. Patent No. 6,581,751. This machine receives a continuous stream of glass articles from a feed conveyor and transports the articles through a series of angularly spaced inspection stations, each of which examines the container according to different criteria. The indexing and inspection machine includes a first arrangement of gripping fingers mounted on a lower carrier, and a second arrangement of gripping fingers mounted on an upper carrier. The rotation of the carriers in a related manner causes the finger arrangements to hold and release the glass articles between the individual fingers, while the rotation of the carriers together causes them to index the glass article between the inspection stations. At least some of the inspection stations include motor rollers for rotating a container about its axis for inspection or for other purposes. Another example of an indexing and inspection machine that could use the optical inspection apparatus and method of the present invention is described in U.S. Pat. No. 3, 313,409, which was mentioned earlier in the background section. The apparatus shown in this patent uses a belt conveyor to transport the containers along a guide. In the general operation, the containers find an indexing head that is circular and having a plurality of cavities circumferentially spaced to receive the containers. The indexing head is successively indexed to bring each container to its position in adjacent inspection stations, which can inspect the containers for commercial variations and / or other characteristics. After the container has been inspected by each inspection station, the container finds a discharge station that ejects it on a conveyor to transport the container away from the machine. Of course, these are only two examples of the machines - that can employ the optical inspection apparatus and method of the present invention, because numerous other machines also exist. Turning now to Figure 1, there is shown a schematic diagram of an inspection station 20 which generally includes a motor roll '24, pairs of back-up rolls 26 and 28 of free running, upper and lower, a controller 30 of rotation of the container, and an embodiment of an optical inspection apparatus 32 of the present invention. A container 34 under inspection is urged by the motor roll 24 against the backing rolls 26, 28 and is rotated by the motor roll 24 about an average axis of rotation A. The axis A depends on the geometry of the container 34 and the spacing between the rollers 26, 28. The axis A is ideally colinear with the central axis of the container. Compare, for example, Figure 9A in which the average axis A is coincident with the axis of the container but the bottom of the container is wrongly inclined / with Figure 9B in which the bottom of the container is perpendicular to the body of the container but the The neck inclined on the container inclines towards the average axis of rotation A with respect to the axis of the body of the container. The drive roller 24 is preferably a component driven by a servo motor that imparts both a radial force and a rotational force to the container 34.

The radial force presses the container between the motor roller 24 and the pairs of idle backing rolls 26, 28, while the rotating force causes the container 34 to rotate about the axis A. Of course, other rotation devices of the bottle could be used in place of the drive roller. The pairs of free running rollers 26, 28, both upper and lower, preferably include two back-up rollers per pair, which together form a V-shaped cavity for rotatably receiving the container and preventing it from being pushed out of the container. sliding plate by the motor roller 24. The apparatus of the invention also preferably, but not necessarily, includes a slide plate 22 on which the bottom of the container remains during rotation. The sliding plate 22 not only provides a reference plane (fi gure 8) for measuring the inclination of the container, but also supports the bottom of the container in a position at or near the foci of the optical measuring devices. . It is also contemplated that the skid plate could be removed, or the container could be out of contact with the skid plate and still be within the scope of the invention. The container rotation controller 30 is operatively coupled to the motor roll 24 and provides electronic signals to a information processor 56 that are indicative of the angular rotation of the container 34. This information of the angular rotation can be based on the rotation intervals angular, fixed, or at fixed intervals of time during which the rotational velocity of the container is constant. It is also possible for the inspection station 20 to include additional components, such as sensors to detect the presence of a container, other parts of the inspection equipment, etc. The optical inspection apparatus 32 is a non-contact optical inspection apparatus which primarily inspects the container support surface to verify the inclination of the container, but can also analyze other parameters such as the depth of the flute, the inclined necks of the container, chair-shaped surfaces or curved support surfaces, to name just a few of the cases The "tilt" of a container is generally measured by the determination of the deflection of support surfaces from a plane that is perpendicular to the axis of the container, if the deviation exceeds a predetermined amount, then the container can be considered as an "inclined bottle". The inspection apparatus 32 preferably includes two optical probes 46 and 48 (Figure 3), each having a light source 50, a lens system 52 and a light sensor 54, as well as an information processor 56 and a screen 58 for .- 'the operator. The light sensor 54 includes an array of sensors 102, which may be an array of CCD areas, or more preferably a linear array of CCD. A diode sensor with side effect can also be used. Although it is preferable that the inspection apparatus have two separate probes inspecting each a separate point on the support surface, it is possible, and is within the scope of the broader effects of the invention, to employ a unique optical probe that emits a beam of light large enough to inspect the two different points. The two points on the support surface are preferably located at the opposite ends of the diameter of the support surface, spaced 180 ° apart from each other, as best shown in Figure 3. For purposes of simplicity, Figures 1 and 2 show only an optical probe; however, the description of one probe applies equally to the other. It is also contemplated within the broader aspects of the invention, that a single probe 46 or 48 can be used, with the output thereof compared to the 180 ° rotation increments. Referring now to Figures 2A, 2B and 3, the portions of the optical inspection apparatus 32 are shown in greater schematic detail. The light source 50 emits an incident line of light energy 60 - that is, a light beam in the shape of a line - upward to an acute angle such that the same focus on and is reflected from the supporting surface 62 of the container. The light source 50 is preferably a structured light source comprising a laser diode 64 for generating a light beam, a lens array 66 for focusing the beam, and a generator for a line 68 for transforming the beam into a line. In an exemplary embodiment, the incident light line 60 is a narrow line of light having a width W where the beam intersects the container, approximately 1.9 cm (0.75 inches); see Figure 3. The incident light is at an angle of 45 ° to the axis A and thus forms an angle of 90 ° with respect to the reflected light beam 80. The lens system 52 (Figures 2A and 2B) is placed between the support surface 62 and a light sensor 54, such that it receives the reflected light beam 80, focus this beam and direct a focused light beam 82 towards the light sensor. The lens system 52 is preferably an anamorphic lens system, and preferably includes a cylindrical lens component 90 positioned adjacent to the component 92 of the spherical or Fresnel lens. The selection of the spherical or Fresnel lens is made, at least in part by its focal length that affects the position of the light sensor 54 with respect to the lens system. The lens system is designed to direct certain light components reflected from the support surface to the light sensor, while other components of the reflected light are directed away from the light sensor. That is, the light reflected from the line 60 of the incident light that is parallel to the primary optical axis (Figures 2A and 2B) of the reflected light beam 80 (Figure 3), even if the reflected light is spaced slightly from this optical axis. (figure 2B), it will be directed to the light sensor 54. In figure 2A, the reflected light beam 80 on the axis 82 is directed on the sensor 54, because the reflected beam 112 is parallel to that deviated from the axis 82. However, the beam 122 which is angled with respect to the axis 80, due to the pointed surface 120, is refracted on the sensor 54 in the same place as the beam 112 strikes the sensor. However, in FIG. 2B, the refracted spokes 81 parallel to the axis 82 are directed onto the array of sensors 102, while the rays on the paths 83, 85 not parallel to the axis 82 are directed away from the array of sensors 102. characteristic improves the insensitivity to the movement of the lateral vessel during the exploration. These and other optical properties improve the practical attributes of the optical inspection apparatus 32, because they allow small amounts of error in the lateral position etc., without rejecting an otherwise acceptable container. Of course, the lens system 52 may have additional features and / or components, such as non-reflective coatings, achromatic properties, etc. The light sensor 54 is positioned below the support surface 62 and near the focal point of the lens 92, in such a way that it receives the light beams from the lens system and transmits the electronic signals representative of the position of the lens. the support surface to the information processor 56. The light sensor 54 is preferably a camera that includes a sensor 102 of the linear array. The linear array sensor comprises an array of CCD sensor elements or pixels placed in a line, each of which registers the intensity of the light that hits this pixel by the assignment to the intensity of a numerical value. According to a preferred embodiment, sensor 102 includes 512 linearly aligned pixels. Alternatively, the light sensor 54 may include an array of the sensor area having one or more rows or columns that provide the information processing device with a two-dimensional image, as opposed to a one-dimensional line of the reflected light . This can be a particularly useful arrangement if the device inspects other parameters of the container. The light sensor 54 can be one of several types of cameras, but is preferably a linear scanning camera such as a high sensitivity linear scan camera of the Dalsa Orion series. The information processor 56 scans the linear array sensor at a predetermined constant interval, either a spatial or a temporal interval, to obtain an image of the light reflected from the support surface 62. The information processor 56 communicates with various components of the inspection station 2C and the total inspection machine, and is capable of analyzing the support surface based on the information received from the light sensor 54 of each probe 46, 48. Preferably, the processor of the The information includes one or more inputs and / or outputs for communicating with the container's rotation-30 controller, the light source 50 and the light sensor 54 of both probes 46, 48, and the operator's screen 58. The information processor also preferably includes first and second electronic processors 96, 98 and a camera controller, to name just a few of the possible components that could be included within the information processor. The first processor 96, also referred to as a pre-processor, comprises the data of the information provided by the light sensor (s) 54 by scanning this information in a range of the container rotation that is greater that the interval in which the processor explores the reflected light. This technique of selecting or compressing data will be explained subsequently in greater detail. The primary or secondary processor 98 receives the compressed information from the pre-processor 96, and executes the algorithms and other commands used by the optical inspection apparatus. Come will be appreciated by those of ordinary skill in the art, comparable electronic devices and combinations of electronic devices could be used instead of the general description of the information processor 56 provided above. In the general operation, each of the two probes 46, 48 emits the incident light line 60 which strikes at a different point on the support surface 62, and each of the probes records the position of the refracted light beams 82. incidents on their respective light sensors 54. A comparison of these two readings allows the inspection apparatus to determine whether or not the container is an "inclined bottle", as well as to determine other parameters of the container. For purposes of simplicity, the operation of only one of the two probes will be described, because they both operate in the same general manner. The incident light line 60 and the reflected light beam 80 shown in the Figures are aligned along what will be referred to as the "nominal optical axes", that is, the axes of the incident and reflected light under the ideal conditions in which the support surface is contained in a plane perpendicular to the axis of rotation A. The "nominal axes" of both incident and reflected light are angled at -45 ° with respect to an axis parallel to axis A. The axes Nominal optics lie in a plane parallel to the axis A. Accordingly, the light sensor 54 generates a stream of data representative of several reflections from the rotating support surface.This data stream is provided to the information processor 56 in the form of a sensor output signal which can be sent directly to the primary processor 98 for analysis, or it may be sent first to the pre-processor 96 for compression. The primary processor uses the signal output information from the sensor to analyze various parameters of the support surface, including the inclination of the container and the depth of the flute. If a container is found to have an unacceptable commercial variation, then this container is labeled as a reject and is removed from the manufacturing process at a downstream station. Referring now to Figures 4A-4D, the optical inspection apparatus 32 is being used to inspect a particular type of support surface 130, especially a fluted surface having a series of splines with peaks 134 and valleys 136. Typically, a The fluted surface is used on the support surface that extends around the circumference of the bottom of the container. When the container is rotated, there are only three sections of each flute that produce reflected beams that actually collide with the light sensor 54, because all the other reflected beams deviate from the sensor. These three scenarios are represented in Figures 4A-4C. In Figure 4A, the incident light 140 is emitted by a light source, reflected from the peak 134 in such a way that a reflected beam 142 is directed towards a light sensor. Because the incident light is reflected from the highest tip of peak 134, the light acts as if it had been reflected from a flat surface perpendicular to axis A. As shown in Figure 4B, the rotation of the container causes the incident light 140 now collides with the fluted surface in a fluted valley 136. As in the previous figure, the reflected beam 144 behaves as if it had been reflected from a plane-surface perpendicular to the axis A. However, the reflected beam 144 is spaced from the reflected beam 142 (shown as a dotted line) by a distance B, such that the reflected beam 144 strikes the light sensor at a point different from that of the reflected beam X42. Figure 4C shows the scenario in which the additional rotation of the container causes the incident light 140 to collide with the grooved surface 130 and cause a double reflection from the slopes of the attached grooves. In this case, the incident light 140 is first reflected from a downward slope of a first groove to an obtuse angle such that it strikes the upward slope of a second adjacent groove, thus causing a second reflection at an angle obtuse. After reflection from these two inclined surfaces, referred to as a double reflection, the reflected beam 146 is directed towards the light sensor and is separated from the beam 142 by a distance C. Again, the different paths taken by the reflected axes cause that the reflected beam 146 collides with the light sensor at a location different from that of the beam 142. If the incident beam hits a groove at any point other than these three points, it is reflected from the surface 130 of the groove in a direction that is deviated from the light sensor. Accordingly, the reflected light which is received by the light sensor 54 during the rotation of the container, is discontinuous, because it records three discrete reflections per flute. Figure 4D is a graph illustrating the output of one of the sensors 54. The points 160 are reflections from the peaks of the grooves (Figure 4A), the points 162 are reflections from the valleys of the grooves (Figure 4B), and points 164 are double reflections from the sides of the grooves (Figure 4C). Typical glass containers have under two flutes per support surface, even though only fifteen flutes are shown here. The distance 170 (FIG. 4D) represents the difference in height between the peak of the highest stria and the peak of the lowest stria of a particular support surface. The difference between the height of these two points is a measurement of the inclination of the container with respect to the average axis of rotation, which if divided by the diameter of the support surface and multiplied by the height of the container, can be used to determine the inclination of the container according to a technique referred to as the Min / Max method. The distance 172 (FIG. 4D) represents the distance between the peak and the valley of a particular groove, or the depth of the groove. The depth of the stria can be taken as a simple reading, or it can be averaged over a number of readings, etc. The double reflection images 164 are not used in the current implementation of the invention. Figure 5 is a schematic representation of a screen at 58 (Figure 1) corresponding to the optical inspections of Figures 4A-4D. More specifically, each of the marks on the graph correspond to a case where the incident light is reflected by the support surface and is received by the light sensor 54. With reference to figures 6 and 7, there a method of compressing the data collected by the light sensor 54 and illustrated in Figure 5 is described, in such a way that the excesses of the memory and processing on the system are minimized. The table of figure 6 is divided into columns and rows; at the intersection of each one is an individual pixel. The value associated with each individual pixel represents the light intensity of this pixel at a particular point in time. For example, in scan 1, pixel 1 of sensor 102 of the linear array recorded a "7", pixel 2 an "11", pixel 3 a "23", etc. The light intensity measurements for twenty-seven separate pixels of the linear array sensor were explored and constitute the first column of data in the table. The container is being rotated simultaneously by the motor roll 24 so that in a subsequent scan, the linear array sensor records a "6" for pixel 1, a "9" for pixel 2, a "0" for pixel three, and etc. This second exploration of the light sensor composes the contents of the second column. The interval 176 successively separates the scans by the light sensor 54, and may be based on either a predetermined amount of time or a predetermined angular amount of rotation of the container. Each row represents the light intensity of a single pixel of the linear array sensor 102 during a series of seven scans. In the duration of a larger interval 178, which happens to be seven scans in the present example, the pre-processor 106 selects the value of the highest light intensity for each pixel on these scans.; a process referred to as "sub-exploration". The data contained in the last column entitled "transferred data" is the only data that is sent to the primary processor 108. Accordingly, the light sensor 54 makes successive scans of the light reflected in the first interval 176, while the The preprocessor makes successive scans of the output of the light sensor in a second interval 17-8 that is greater than the first interval. The optical inspection apparatus of the present invention is capable of determining the inclination of the container with only a fraction of the data that might otherwise be required, and because the higher intensity value is sent, there is no appreciable reduction in the accuracy of the inspection. As an alternative in the selection of the maximum values for each pixel on the scanning interval 178, the pre-processor could calculate the average intensity of the pixel, etc. The selection of seven scans for the compression of the data in a similar way is not critical. A graph representing the sub-scanned information sent by the pre-processor 106 according to this method is observed in Figure 7. The graph of Figure 7 is a compressed version of the graph of Figure 5. More specifically, the marks that are broken in the various bands 160, -164 of figure 5 have been removed, thus leaving the uninterrupted bands 180-184, condensed, of figure 7. Because most of the data that are removed correspond to spots, there is no loss of significant data and therefore there is no appreciable loss in accuracy. In the example of a 504-line image, each vessel is scanned 504 times during a single revolution of the vessel, or approximately every 0.71 °. If the data is transferred after every 7 / a. scanning, then only 72 lines of data are actually sent to the primary processor 108, instead of 504 lines. An object of this method, therefore, is to compress the data for analysis while retaining enough information to perform exactly the inspection. As previously mentioned, the interval between the scans by either the light sensor or the preprocessor may be based on either a predetermined rotational displacement of the container, such as 0.71 °, or a predetermined amount of time. This method provides many benefits to the optical inspection apparatus 32, including but not limited to, a tilted, false, low bottle deformation speed, a high defect capture rate, a faster, faster edge detection time. , and lower memory requirements. With reference to Figure 8, another method that can be used by the optical inspection apparatus 32 to analyze the support surface was described. This method uses a technique referred to as the least squares adjustment technique. An object of this method is to derive a mathematical expression of the support surface 62 that matches the measured data taken with respect to a plane 22a (which may be the surface of the slide plate 22), and to determine whether the container it is or not a bottle inclined from this expression. The mathematical expression used here represents the differential height between two points on the supporting surface, as a function of the angular position. The two positions correspond to the positions where the probes 46 and 48 strike the support surface with the incident light.

The container 200 has a support surface 62, and two points 204, 206 that are located on the support surface at a 180 ° separation. The height or axial extension of the points 204 and 206, with respect to the reference plane 22a, is referred to as h2 and hi, respectively. When the container 200 is rotated about its axis A, the distances hi and h2 change according to the angular position of the container. In mathematical terms, the difference between the heights hi and h2 can be represented by the following sinusoidal expression: .- ._ and (I) = h2 (I) - h? (I) = a0 + * sin (2pI / N +? 0) (Equation 1); where ao is the average axial runoff of the support surface from the plane, a is the amplitude of the sine wave and is the primary variable for which it is resolved, N is the sine wave cycle, and? 0 is the initial phase of the sine wave. Therefore, an object of this method is to use the post-least squares adjustment technique to calculate a value for "a" so that the previous expression better models the measured data provided by the light sensor 54. A linearization of the expression (1) it makes it easier to apply the least squares adjustment technique with respect to the measured data, and provides the value of a: y (I) = a0 + a * sin (2pI / N +? 0) = a0 + a * cos? 0 * sin (2pI / N) + a * sin? 0 * cos (2pI / N) = a0 + a1 * sin (2pI / N) + a2 * cos (2pI / N) (Equation 2) a = V (a? 2 + a22) (Equation 3). Once the amplitude a of the sine wave is known, the inclination of the container can be calculated by the following equation: Tilt = a * Container Height / diameter (Equation 4). If the calculated inclination exceeds a predetermined amount, then the container is considered a "tilted bottle" and is rejected. The use of the previous least-squares technique requires some initial knowledge of the sine wave, such as "the N-cycle of the sine." The calculations and the least squares analysis of the resulting sine wave described above are often times-long consumers, especially if an exhaustive search of the N-cycle of the breast is supplemented In an effort to minimize the amount of calculation time required, an additional technique referred to as a gold section search technique can be employed. a linear search method to achieve the fast and accurate search of the N-cycle of the breast, and is only necessary during the establishment for the inspection of the design of a particular bottle.Once the N-cycle of the breast is found, then the same It becomes a known parameter in equation 1. For any vessel, the initial estimates of the sine-cycle are can do based on the revolutions by size and the number of scan lines in the image- (for example, 72 scan lines in the previous example) ". Once the initial estimates are made, a linear search that has a golden search relation of 0.168 is performed over a closed interval. An object of this search is to use multiple interactions to determine a N-cycle of the sine that provides a minimum adjustment error. For example, a first iteration of the linear search involves the search for a first range of possible N values that includes points from the golden section i and N2. This first interval starts at a "start" value, extends along a line through points N2 and i of the golden section, in this order, and ends at a "final" value. The adjustment error in i referred to as Q (N?), Is compared with the adjustment error in N2 referred to as Q (N2). If Q (N?) Is > Q (N2), then the optimum N value lies along the line between the starting point and the golden section point Nx; if Q (N?) is < Q (N2), then the optimal N value lies along the line between point N2 of the golden section and the end point. Therefore, the second interval of the linear search 'is above either the start interval-Ni or N2-end, both of which are smaller intervals than the first interval. The second iteration of the linear search requires the selection of new points of the golden section, because the values of Ni and N2 are not longer in the middle part of the search interval. In the case where the interval of the second search iteration is from the beginning-Ni, the new points N3 and N4 of the golden section are selected in such a way that they are within this interval and the point N4 is equal to N2 Again, the adjustment errors Q (N3) and Q (N4) are calculated for each of the new points of the golden section; but because point N4 is equal to point N2, only Q (N3) needs to be calculated. If Q (N3) is > Q (N2), then the optimal N value lies along the line between points N3 and i of the golden section; if Q (N3) is < Q (N2), then the optimal N value lies along the line between the starting point and point N2 of the golden section. In this way, each iteration of the search is above a smaller and smaller interval until the process converges on an optimal N value that minimizes the adjustment error. Another technique that can be used by the optical inspection apparatus of the present invention to improve the least squares adjustment method involves the use of the Min / Max values. Not all the points measured by the optical inspection apparatus are necessary to solve equation 1, because this equation can be solved exactly by selecting only those points within a certain distance of a Min / Max value. In effect, the calculation of the least squares algorithm is faster with fewer data points. For example, if a point A represents the maximum point for the height differential curve expressed in equation 1 and point B represents the minimum point, then this technique selects only those points that fall within a predetermined range, say within 15 % of the difference - between points A and B. The method of least square squares can then be performed on only these points. If this fails to provide sufficient points to prove accuracy, simply increase the percentage to a level that supplies enough points. Thus, an optical inspection apparatus and method has been described for inspecting the support surface of a container, which fully satisfies all the objects and goals previously described. Several alternatives and modifications have been described. Other alternatives and modifications will be easily suggested by themselves for people of ordinary experience in the art. For example, the pre-processor 106 is shown to be included within the information processor 56, however, the pre-processor could only be easily incorporated into the light sensor 54 or other appropriate component. Also, the incident light line 60 is described as a line of light having a predetermined width W, but it is possible for the light source 50 to emit an incident light beam instead. Most of the above description pertains to the inspection of grooved surfaces, however, smooth or no-groove bearing surfaces could easily be inspected. In the case of a smooth support surface, either with or without a set ring, the reflected light beam, received by the light sensor, could be a continuous beam. The invention is proposed to encompass all such alternatives and modifications that fall within the spirit and broad scope of the amended claims. It is noted that in relation to this date, the best method known to the applicant to carry out the aforementioned invention, is that which is clear from the present description of the invention.

Claims (20)

1. CLAIMS Having described the invention as above, the content of the following claims is claimed as property. An apparatus for inspecting the inclination of a container having a container support surface, characterized in that it includes: means for maintaining a container in position and rotating the container around an axis, a light source placed under the container for directing the light energy on the container support surface in said means, a light sensor placed under the container to receive portions of the light energy from the source reflected from the container support surface, and an information processor coupled to the light sensor to determine, as a combined function "of the reflected light energy and the rotation of the container, the deviation of the supporting surface of the container from a plane perpendicular to the axis 2. The apparatus in accordance with the claim 1, characterized in that the container includes a grooved portion around the support surface of the container, and the image processor acts in response to the reflected light energy to determine the depth of the groove. The apparatus according to claim 1 or 2, characterized in that the information processor includes a pre-processor to scan the light sensor in first increments of rotation of the container-, and a main processor to receive the data. of exploration from the pre-processor in second increments of the rotation of the container, greater than the first increments. The apparatus according to claims 1, 2, or 3, characterized in that the means for holding the container in position and rotating the container about an axis include spaced backing rollers for externally coupling the container, and a roller motor for coupling and turning the container while holding the container against the backing rolls to define an average axis (A) of rotation as a function of the geometry of the container and the spacing between the backing rolls. 5. The apparatus according to claims 1, 2,. 3 or 4, characterized in that it comprises two of the light sources and two of the light sensors placed in pairs on the diametrically opposite sides of the axis, the information processor functions in response to the compression of the outputs of the sensors of. light to indicate the inclination of a container. The apparatus according to any preceding claim for inspecting a support surface having a plurality of grooves, characterized in that the source of the light and the sensor are such that the grooves cause the light sensor to receive non-continuous reflections from a peak of the stria and a valley of the stria. The apparatus according to claim 6, characterized in that the output signal of the sensor includes at least first outputs that represent the reflections from the peak of the groove and second outputs that represent the reflections from the valley of the groove. The apparatus according to claim 7, characterized in that the information processor is adapted to use the first outputs to determine the inclination of the container. The apparatus according to claims 7 or 8, characterized in that the information processor is adapted to use both the first and the second outputs to determine the depth of the groove. 10. The apparatus according to any of the preceding claims, characterized in that the information processor is adapted to generate a sinusoidal expression representative of the difference in altitude between two positions spaced on the support surface. 11. The apparatus according to claim 10, characterized -because the information processor uses a least squares adjustment technique to derive the values for one or more variables of the sinusoidal expression. 12. The apparatus according to claim 11, characterized in that the derived values are used to determine the inclination of the container. The apparatus according to claim 11 or 12, characterized in that the information processor uses an iterative search method to determine a sinusoidal cycle for the sinusoidal expression. The apparatus according to claim 13, characterized in that the iterative search method is a search of the golden section. 15. The apparatus in accordance with the claim 11, characterized in that the information processor also uses a selection process involving the Min / Max data points to improve the efficiency of the least squares adjustment technique. 16. A method for inspecting a support surface of a container, characterized in that it comprises the steps of: (a) providing _. a light source generally turned toward the support surface, (b) providing a light sensor generally turned towards the support surface, (c) rotating the container about an axis (A), (d) causing the light source emits light that is reflected out of a position on the support surface, (e) causing the light sensor to register the position over which the reflected light hits the light sensor, and (f) Analyze the position data, the deviation of the support surface from a plane perpendicular to the axis. 17. The method according to claim 16, characterized in that the support surface which is inspected is a grooved surface. 18. The method according to claim 16, characterized in that step (e) includes the compression of the data from the recorded position data. The method according to claim 16, characterized in that step (f) includes the use of a sinusoidal expression to model the support surface of the container. 20. The method according to claim 16, characterized in that one or more variables of the. Sinusoidal expression are solved using a least squares adjustment technique.