MXPA99004896A - Inspection of containers through the use of a single area arrangement detector and selected light sources alternativame - Google Patents

Abstract

An apparatus for inspecting a container (12) including a first light source (14) for generating light energy of a first character and directing light energy over a predetermined portion (20) of a container under inspection and a second light source (22) for generating light energy of a second character different from the first character and directing said light energy on the same predetermined portion of the container under inspection. An area array detector (26) is arranged to receive a two-dimensional image of the portion of the vessel illuminated by the first and second light sources. The first and second light sources are selected sequences and alternatively and first and second two-dimensional images of the portion of the container under inspection are discharged from the detector. Commercial variations that affect the optical properties of the containers are identified by comparing the first and second two-dimensional images of the respective light sources explored by the detector. The detector preferably includes equipment (44, 46, 48) for scanning the two-dimensional images in sequential frames and the first and second images are obtained by scanning sequential frames of the detector during which the first and second light sources are selected alternatively.

Description

INSPECTION OF CONTAINERS BY THE USE OF ONLY SELECTED AREA ARRANGEMENT DETECTOR AND SOURCES OF LIGHT ALTERNATIVELY DESCRIPTION OF THE INVENTION The present invention is concerned with the inspection of containers in terms of commercial variations that affect the optical properties of the containers and more particularly with a method and apparatus for inspecting containers based on the comparison of two-dimensional images. (or two-dimensional) of the inspected portions of the container.

BACKGROUND AND OBJECTS OF THE INVENTION In the manufacture of transparent containers such as bottles and glass cylinders, various types of anomalies may occur in the side walls, heels, bottoms, shoulders and / or necks of the containers.

These anomalies, termed "commercial variations" in the art, can affect the commercial acceptance of the containers. It has been proposed so far to employ electro-optical inspection techniques to detect commercial variations that affect the optical properties of the containers. The basic principle is that a light source is positioned to direct the light energy over the container and a camera is positioned to receive a REF .: 30431 image of the portion of the container illuminated by the light source. The light source can be of uniform intensity or it can be configured to have an intensity that varies across a dimension of the light source. Commercial variations in the portion of the container illuminated by the light source are detected as a function of the intensity of the light in the image of the illuminated container received and stored in the chamber. U.S. Patent No. 4,945,228 assigned to the assignee hereby discloses an apparatus for inspecting the sealing surface of the finish of a container including a light source positioned to direct light energy onto the sealing surface of the container as the container The container is held in a stationary position and rotated about its central axis. A camera that includes a linear array or arrangement in matrix (area) of light-sensitive elements is positioned and oriented with respect to the axis of rotation of the vessel to receive the light energy reflected from the sealing surface, the camera has a field effective display limited to an angular portion less than the entire circumference of the sealing surface of the container. The camera array is passed in increments of container rotation to reveal information indicating the intensity of light in each element of the array as a function of such increments and commercial variations in the sealing surface of the vessel are detected as a function of such information. . The apparatus thus described is well adapted to detect commercial variations that affect the reflectivity of the sealing surface of the container, such as variations of finish on the line, blisters, stones and dirty finish of the container. U.S. Patent No. 5,489,987 also assigned to the assignee herein discloses an apparatus for inspecting the sealing surface area of a container that includes a light source positioned to direct a narrow beam of light energy at an acute angle over the surface area. of sealing a container as the container is rotated about its central axis. A light detector is arranged to receive the narrow beam of light energy reflected from the sealing surface area and provides an output signal that varies as a function of the incident position of the beam of light reflected on the detector. That is, the reflected light beam is incident on the detector in a position that varies with the height or level of the sealing surface with respect to the light source and the detector and the detector is characterized in that it provides an electrical output signal which varies as a function of the position of incidence of the beam of light reflected on the detector. Variations in the height in the area of the sealing surface are detected as a function of the output signal of the detector. In one embodiment, light source / detector pairs are arranged on diametrically opposite sides of the container axis and warping, immersion and / or inclinations in the incident position of the light beams reflected on the detectors as the container rotates. Copending US Patent Application Serial No. 08 / 856,829 also assigned to the assignee of the present invention discloses a method and apparatus for inspecting the sealing surface of a container. In one embodiment, first and second light sources direct the light energy on the sealing surface of a container from different angles with respect to the container axis and the nominal plane of the sealing surface. The light energy reflected by the area of the sealing surface of the container of the first and second light sources is directed outward onto an area array detector, such that the detector effectively visualizes the sealing surface area from two. different angles corresponding to the lighting angles of the light sources. The different light sources are of different structure or nature to illuminate the sealing surface with light having different properties, as well as also different lighting angles to detect different physical and / or dimensional characteristics of the sealing surface of the container. The light sources are alternatively energized and the area array detector is passed to reveal two-dimensional sequential images indicating different sealing surface characteristics. Inaccuracies associated with the movement of the container between the sequential frame scans and the ambient light incident on the area array detector during each picture frame may arise. When the subject matter of this co-pending application is implemented in the so-called cold end of the container manufacturing process, in which the container is held in a stationary position and rotated about its central axis, the container will not only undergo a finite rotation between the sequential frame sweeps but also can be laterally undulated between the sequential frame sweeps. Also when implemented in the so-called hot end of the manufacturing process in which a container is moved in a direction transverse to its axis below the inspection apparatus, the sealing surface of the container (or other area that is inspected) will move a Finite distance between sequential frame sweeps. It is important, in obtaining reliable inspection information, to minimize the effects of vessel movement and ambient light during the inspection operation. It is a general object of the present invention to provide a method and apparatus for the inspection of a container in which one or both of these objectives are carried out.

BRIEF DESCRIPTION OF THE INVENTION An apparatus for inspecting a container according to a currently preferred embodiment of the invention includes a first light source for generating light energy of a first character and directing light energy over a predetermined portion of a low container. inspection and a second light source for generating light energy of a second character different from the first character and directing said light energy on the same predetermined portion of the container under inspection. An area array light detector is arranged to receive a two-dimensional (or two-dimensional) image of the portion of the container illuminated by the first and second light sources. The first and second light sources are energized sequentially and alternately and first and second dimension images of the portion of the container under inspection are discharged from the detector. Commercial variations that affect the optical properties of the containers are identified by comparing the first and second two-dimensional images of the respective light sources scanned from the detector. The detector preferably includes equipment for scanning two-dimensional images in sequential frames and the first and second images are obtained by scanning sequential frames of the detector during which the first and second light sources are alternately energized. The first and second light sources are selected during the associated scan frames in the area array detector. In some embodiments of the invention the first light source is selected at the end of a first scan frame and the second light source is selected at the start of a second scan frame, which minimizes the effects of the movement of the vessel between the frames . In other embodiments of the invention, the integration of the light energy in the individual pixel elements of the detector is controlled during the scanning frames to minimize the effects of ambient light. The first light source is selected at the end of the first frame and the second light source can be selected at the end of the second frame to minimize the effects of ambient light. Alternatively, the second light source can be selected at the beginning of the second frame to minimize the effects of the movement of the vessel and the pixel data can be desynchronized from the detector during the second frame, such that the effects of ambient light are " deteriorated "throughout the second frame picture. The effects of such fuzzy ambient light can be minimized by employing the so-called edge magnitude detection techniques to obtain the two-dimensional image of the second scan frame as a function of a comparison between the same signals of the pixel element in adjacent scanned lines. . A method for inspecting a container for variations that affect the commercial acceptance of the container according to another aspect of the invention includes the steps of alternately directing first and second light energies of different character over a portion of the container, obtaining first and second two-dimensional images of the container portion during illumination by the first and second light energies respectively and detect commercial variations in the container that affect the optical properties of the container by comparison of the first and second images. The first and second light energies are alternately directed over a single area array detector to develop the two-dimensional images of the illuminated portion of the vessel and scan or scan the two-dimensional images of the detector. Two-dimensional images are compared to detect commercial variations in the container by superimposing the images, preferably by using one of the images to predict areas of possible presence of variations in the other of the images. In the preferred embodiments of this aspect of the invention, the first and second two-dimensional images of the illuminated portion of the container are obtained by controlling the detector in sequential scan frames of equal duration of time, directing the first and second light energies on the vessel during first and second sequential associated scan frames in the detector and scanning the detector during the first and second scan frames to obtain the desired two-dimensional images of the illuminated portion of the vessel. More preferably, the first light source is selected to direct light energy over the vessel and the detector during a small portion of the first scan frame and the second light source is selected to direct light energy over the vessel and the detector during a small portion of the second scan frame. The first light source is preferably selected at the end of each first scan frame and the second light source can be selected either at the beginning or end of each second scan frame depending on the control technique and frame scan employed . The integration time of the first frame can be limited to the short selection time of the first light source, thus giving the integration of ambient light in the first frame. More preferably, the second light source is selected at the beginning of each second scan frame and the detector is controlled to integrate the light energy of the second light source during the entire second scan frame. The detector is scanned during the second scanning frame per pixel line in the detector, such that the effects of ambient light during scanning of the second frame are erased in all sequential pixel lines scanned from the detector. By employing edge magnitude detection techniques in which each pixel signal on each scanned line of the detector is compared to the same pixel signal on the next scanned line of the detector, the blurring effects of ambient light are minimized.

BRIEF DESCRIPTION OF THE DRAWINGS The invention, together with objects, features and additional advantages thereof will be better understood from the following description, the appended claims and the accompanying drawings in which: Figure 1 is a schematic diagram of the apparatus for inspecting the sealing surface of containers according to a currently preferred embodiment of the invention; Figure 2 is a fragmentary schematic diagram illustrating a modification to the embodiment of Figure 1; Figure 3 is a functional block diagram of a frame transfer CCD detector that can be employed in the camera of Figure 1; Figures 4A, 4B and 4C illustrate respective two-dimensional images of the container under inspection and are useful for describing the operation of the invention. Figures 5A, 5B, 5C and 5D illustrate respective two-dimensional images of the selected portion of the container of Figure 1 and they are useful for describing the operation of the invention and Figures 6, 7 and 8 are timing diagrams illustrating the scanning of the camera of Figure 1 according to three respective embodiments of the invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The description of the copending US patent application indicated above Serial No. 08 / 856,829 is incorporated herein by reference. The above-mentioned U.S. Patent No. 4,958,223 is incorporated herein by reference.

Figure 1 illustrates an apparatus 10 for inspecting a container 12 according to a currently preferred embodiment of the invention. A first light source 14, such as an LED transmitter 16, is disposed above the container 12 and is oriented to direct light energy through a diffuser 17 and a set of Fresnel lenses 18 downwardly on the surface of sealing 20 of the container 12. A second light source, such as a laser, is also disposed above the container 12 and is oriented to direct a light beam in the form of a narrow line downwardly on the sealing surface 20 in a position coincident with the LED light beam 16. The diffuse light of the LED light source 14 illuminates the entire radial portion and a portion of the circumferential dimension of the sealing surface, while the light beam in the form of a line of the laser light source 22 is oriented laterally or radially of the sealing surface. A camera 24 has an area arrangement detector 26 on which the light energy reflected from the sealing surface 20 is focused by the lens 27, 28. The camera 24 is positioned above the sealing surface 20 and oriented to receiving the light energy reflected by the sealing surface of the LED light source 14. That is, the camera 24 and the detector 26 are oriented with respect to the LED light source 14 such that the light energy of the LED 16 is normally reflected by the sealing surface 20 in the nominal flat position of the surface of sealing through the lenses 27, 28 on the detector 26. On the other hand, the laser light source 22 is oriented at a sharper angle to the sealing surface 20, such that the incident light energy of the same on the sealing surface 20 is reflected on the detector 26 by means of the lens 28, 29, a mirror 31 and a beam splitter 33 disposed between the lenses 27, 28. A conveyor that normally includes a star wheel and a sliding plate is disposed and attached to a source 12 of containers for moving the successive containers through an arcuate path and bringing the successive containers to a position in the apparatus 10 between the light sources 14, 22 and the chamber 24. The device 10 is preferably available at a station of a starwheel conveyor vessel inspection system of the type shown in U.S. Pat. Nos. 4, 230,319 and 4,378,493, the description of which are incorporated herein by reference for the purpose of background. Thus, the successive containers 12 are held stationary below the light sources 14, 22 and the chamber 24 and rotated by a drive roller 30 or the like around the central axis of each container. An encoder 32 is coupled to the rotation mechanism of the container to provide signals indicative of increments of rotation of the container. Such increments may comprise either fixed angular rotation increments or fixed rotation increments in time at constant speed. An information processor 34 is coupled to the encoder 32, the camera 24 and the light sources 14, 22 to control the operation of the light sources 14, 22 and the scanning of the camera 24 as will be described. The information processor 34 is also coupled to a display or indicator 36 to provide an alphanumeric and / or graphic indication of vessel inspection information to an operator and a reject mechanism 38 to remove from the conveyor system vessels that do not pass the inspection . The embodiment of the invention illustrated in Figure 1 is particularly suitable for implementation in the so-called cold end of a glass manufacturing system after the containers have passed through an annealing furnace and in which the containers are sufficiently cold to be handled by a gear wheel and roller conveyor, drive. The principles of the invention can also be implemented in the so-called hot end of the manufacturing system between the glass making machine and the annealing furnace. The glass containers manufactured in a single-section machine, for example, are transferred on a linear conveyor 40 (Figure 2) onto which the containers are transported in line from the manufacturing machine to the annealing furnace. The conveyor 40 is coupled to a conveyor drive mechanism 42 which can provide the information processor 34 (Figure 1) with indications of increments of the movement of the container on the conveyor. The apparatus 10 in Figure 1 can be disposed above the conveyor 40 in such a way that a container 12 on the conveyor 40 passes under the light sources and the chamber for inspection of the sealing surface of the container as will be described. In this implementation, the camera can be passed through increments of linear movement of the conveyor transverse to the axis of the container. There are a variety of camera / scan options that can be used in applications where the vessel moves instead of turning under the light sources. For example, a high-resolution camera can be used to obtain a pair of images of the entire finished one. A rectangular area array detector can be used to obtain multiple "slices" of the finish as it moves under the inspection head. A low resolution camera can be used in combination with servo-driven mirrors to visualize the entire circumference of the finish as the container moves under the inspection head.

The containers are placed on the conveyor 40 by the manufacturing machine in a predetermined and continuous sequence according to the mold and the section of the machine. The information processor 34 can provide information indicating trade variations on the sealing surface of the container and / or implement adjustments or corrections in the manufacturing machine to correct any commercial variation noted. The area array detector 26 of the camera 24 comprises a plurality of CCD image elements or pixels arranged in a rectangular row and column arrangement. The pixel elements are characterized by the fact that they are sensitive to the incident light energy to provide an electrical signal indicating the amount of the total amount of incident light energy on the pixel element. In other words, when allowed to be put into operation, each pixel element effectively integrates the amount of incident light energy thereon. The detector according to the present invention preferably comprises a frame transfer CCD detector. In general, this type of CCD area array detector comprises an image section containing the multiplicity of pixel elements, a memory section to which signals from the pixel element can be transferred and a read-through register. of which the signals of the pixel element in the memory section are transported for their transfer from the detector. Figure 3 illustrates a frame transfer detector 26 that includes an image section 44 that contains the array of pixel elements. The image section 44 is connected to a frame memory section 46, which in turn is connected to a read register 48 for transporting image data to the information processor 34 (FIG. 1). The control signals of the information processor 34 for controlling the operation of the detector 26 include an integration enable input to the image section 44 and transfer control inputs to the image section 44, the frame memory section 46 and 48 reading recorder. In general, the frame transfer detector 26 transfers one frame one line at a time. Thus, a line or row of pixel signals is transferred from the image section 44 to the frame memory section 46, while a line or row of signals in the frame memory section 46 is transferred to the reading recorder. . This process continues until an entire frame is transferred. The frame transfer detector 26 is well known in the art. In general, the information processor 32 (Figure 1) alternately energizes the LED light source 14 (light emitting diode) and the laser light source 20 and scans associated two-dimensional images of the sealing surface of the detector vessel 26. of camera arrangement of the camera 24. By comparing the image in the camera of the LED light source 14 with the image in the camera of the laser light source 22, useful information can be obtained. For example, with reference to Figures 4A-4C, the information processor 34 can obtain from the camera 24 a two-dimensional image 52 of the segment of the sealing surface 20 illuminated by the LED light source 14. By employing this image 52, the information processor 34 determines the position of the sealing surface 20 and predicts a position 54 for any wire edge or overpressure that may be disposed in the drop area into the interior of the sealing surface. Then the information processor 34 analyzes the scanned image 56 of the detector 26 during illumination by the laser light source 22, from which two reflection areas 58 are noted. The reflection 58 is from the top of the sealing surface 20, while the reflection 60 is from the area of radially immediate descent into the interior of the sealing surface. By analytically superimposing the images 52, 56 and thereby develop a composite image 62, the information processor 34 can determine that the reflection 58 is associated with the sealing surface 20, while the reflection 60 is in the drop area 54 within which You can expect a wire edge or overpressure. Thus, the reflection 60, being within the wire edge area or overpressure 54, can be compared by its position with respect to the reflection 58 to determine if the wire edge is of sufficient height to constitute an overpressure condition that needs the rejection of the container and possible corrective action in the mold of the original manufacturing machine. This comparison can be carried out automatically inside the information processor 34 by means of a pixel in pixel comparison of the images 52, 56 or it can be carried out manually by an operator on the screen 36 in which the image is shown. Composite 62. Figures 5A-5D illustrate three sequential composite images 62a, 62b, 62c with respect to a sealing surface 20 of the container. That is, the information processor 34 (Figure 1) energizes each light source 14, 22 and scans the detector 26 as each light source is energized to obtain a composite image 62 at each increment of rotation of the container. Figures 5A-5D illustrate three such composite images 62a, 62b, 62c in three increments of container rotation. In each image the sealing surface 20 is clearly illustrated as illuminated by the LED light source 14. Within the image 62a, a variation of the finish on the line is indicated at 64 and a second variation of the finish on the line is indicated at 66a. However, because the image 62a only captures a portion of the termination variation 66a on the line, this variation could be omitted or ignored in the image processor. The full variation of the finish on the line is shown at 66b in the image 62b. Thus, by controlling the operation of the light sources 14, 22 and scanning the camera 24 to obtain the superimposition of the images 62a, 62b, 62c, a variation 66b of the termination on the line that could otherwise be omitted is detected. because it lies adjacent to the border between sequential frames. Other sources of light, such as a divided LED (crizzle LED) could be used in combination with the light sources 14, 22 as described in the copending patent application referenced above. Thus, in order to obtain two different images of the two light sources, a light source illuminates the container during a camera frame and the other light source illuminates the container during the next camera frame. The pictures of the camera are of equal duration. This sequence is repeated as the container is rotated (figure 1) or moved (figure 2). The pixel data accumulated in the camera detector can be downloaded from the pixel array, after which the individual pixels can integrate new image data. The normal method of taking two consecutive images with a single camera is to select the two light sources in two adjacent camera frames and therefore the acquisition of the two images would be separated by a frame time. In a 128 x 128 high-speed area array detector, the camera can be synchronized at 16 MHz, such that the time allocated for each frame would be 1 ms. For an inspection machine that operates at 360 bottles per minute (50% of the time used for inspection and each bottle rotates 1.5 times per inspection period) and with bottles that have a finished 2.5 cm (1 inch) diameter , the finish will rotate approximately 0.152 cm (0.060 inches) in 1 ms. If the handling of the bottle is less than optimal and the bottle is moved radially one part by two parts of circumferential movement in a short distance, then the finished one would move radially 0.076 cm (0.030 inches) in each frame time of 1 ms. This could easily move the reflection 58 from the sealing surface (Figures 4B and 4C) to the wire edge area 54, to cause for example a false detection of a wire edge or overpressure. In addition, the acceptance and integration of the ambient light in a frame time of 1 ms would produce an undesirable signal-to-noise ratio in the camera. It is preferable to select the light sources 14, 22 for a very short time, such as of the order of 15 microseconds. The container will only rotate approximately 0.0025 cm (0.001 inches) during this time, which reduces motion blur. In addition, the integration time can be limited to a duration of 15 microseconds of the selection of each light source. Figure 6 illustrates a light source and frame sweeping control technique that can be employed. The LED light source 14 is selected at the end of the frame 1 and the laser light source 22 is selected at the beginning of the frame 2. The pixel data is transferred from the image section to the memory section during the periods of interframe and are downloaded from the detector readout recorder to the image processor during the subsequent frame. (It will be appreciated, of course, that "Table 1" and "Table 2" in Figure 6 and Figures 7-8 alternate continuously during the operation. Thus, Table 1 and Table 2 in Figure 6 may be associated with the composite image 62a in figure 5A for example, the next sequence of frame 1 - frame 2 would then be associated with the composite image 62b, etc.). By selecting the LED light source 14 at the end of the frame 1 and the laser light source 22 at the beginning of the frame 2, the time delay between the illuminations by the light sources is minimized, in such a way that the container does not it will have moved significantly between obtaining the two-dimensional images associated with tables 1 and 2. This technique minimizes the problem of container movement between frame scans, but does not address the problem of ambient light falling on single camera detectors . The pixels in the detector 26 will receive and integrate the ambient light for the entirety of both frames 1 and 2 in Figure 6 and the data associated with this ambient light will be transferred to the image processor. Figures 7 and 8 illustrate light source and scan or frame scan techniques that make use of an available capacity in many area array detectors to allow integration into the individual pixel elements by means of a control signal that enables the integration, coming from the information processor 34. Thus, the pixel elements in the detector array will be enabled to integrate the incident light thereon by the duration of the enable signal, but they must transfer data during the signal of enabling or pixel data will be lost. When they are not enabled, the pixels are effectively neutralized. Figure 7 illustrates another technique that makes use of this feature. The integration of the pixel is enabled at the end of frame 1 and at the end of frame 2. The LED light source 14 is selected at the end of frame 1 and the laser light source 22 is selected at the end of frame 2. The data pixel values are transferred during the interframe periods immediately following tables 1 and 2 and are downloaded by means of the read logger during the subsequent frame period. The technique illustrated in Figure 7 effectively solves the problem of ambient light incident on the pixels by enabling integration into the pixel elements only at the time when the associated light source is selected. However, a significant movement of the container under inspection between the image scan periods and the end of frames 1 and 2 will be performed. Figure 8 illustrates a light source and frame scanning control technique that is currently preferred. The integration of pixel data is enabled at the end of table 1, during which time the LED light source 14 is selected as previously described. Then the pixel data is downloaded during the interframe period between Table 1 and Table 2. The accumulation of ambient light during Table 1 is thereby minimized. The integration of the pixel data is again enabled at the beginning of frame 2 and the laser light source 22 is selected at the beginning of frame 2. This minimizes the effect of movement in the vessel between the times when the light sources They are selected. At this point both images of the source 14 and the source 22 are completely on the detector 26 at the same time. The data transfer is started immediately after the laser light source is selected. However, the integration must remain enabled by the data transfer period of the image section 44 to the storage section 46 or 50 (Figures 3A and 3B) in such a way that this data is not lost. This allows some ambient light to enter into frame 2 during the time when the pixel element data is desynchronized from the area array detector. Thus, the data (from Table 1) are desynchronized from the image section of the detector at the same time that the data (from Table 2) is out of synchrony with the reading logger. The image section of the detector will continue to integrate the light until it is synchronized in the storage section. The first line synchronized to the storage section will have a very short integration time. However, the last line synchronized to the storage section will have a full picture of ambient light integration time. This has the effect of scattering or "erasing" ambient light throughout the frame. The last line of image data is first integrated into the upper part of the image and continues to integrate the ambient light as the data is transferred one line at a time in the image section of the array. The data line moves through the image section of the array throughout the integration time. The data line integrates different ambient light at each point of the image and therefore effectively "erases" the ambient light image. The image of the selected light source is not deleted. In theory, this improves the integration of ambient light by an average factor of two. However, in practice, ambient light when the camera focuses on a container is not uniform throughout the entire image. If the ambient light is centered in the frame and is one tenth of the total height, then any pixel line at most will be in front of this environmental image on the array for only one tenth of the total frame time, to reduce the amplitude maximum by a factor of ten. Thus the ambient light is effectively zero in the first scanned line of the image section and in the full amplitude of one tenth in the last scanned line of the image section. It is preferred to employ edge magnitude detection techniques to develop each scan image. This technique involves comparing each pixel element data of each line with the data of the corresponding pixel in the preceding line and the input of image data as a function of the difference between them. The comparison threshold can be adjusted to accommodate the blur of ambient light, such that only a true image border will be detected. This light control and frame scanning technique takes advantage of the architecture of commercially available CCD detectors and non-expensive cameras, although the synchronization logic in the camera must be modified as described. 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 (30)

1. Claims Having described the invention as above, the content of the following claims is claimed as property: 1. An apparatus for inspecting a container, characterized in that it comprises: a first light source for generating light energy of a first character that includes means for directing light energy from the first source on a predetermined portion of a container under inspection, a second light source for generating light energy of a second character different from the first character, including means for directing light energy from the second character source to the same predetermined portion of the container under inspection, an area arrangement light detector arranged to receive a two-dimensional image of the portion of the container illuminated by the first and second sources, means for sequentially and alternately energizing the first and second sources of light and download the detector the first and s Two alternate two-dimensional images of the container portion as illuminated by the first and second sources respectively and means for comparing the first and second two-dimensional images to identify commercial variations that affect the optical characteristics of the container.
2. 2. The apparatus in accordance with the claim 1, characterized in that the detector includes means for scanning dimensional images on it in sequential frames and wherein the first and second images are obtained by scanning sequential frames of the detector during which the first and second light sources are illuminated respectively from alternative way.
3. 3. The apparatus in accordance with the claim 2, characterized in that it further comprises means for selecting the first light source during the first associated frames in the detector and means for selecting the second light source during second associated frames in the detector.
4. 4. The apparatus in accordance with the claim 3, characterized in that the first light source is selected at the end of the first frame and the second light source is selected at the beginning of the second frame.
5. 5. The apparatus of compliance with the claim 3, characterized in that the area array detector has a plurality of individual detector pixels adapted to integrate the incident light energy thereon and to provide pixel signals as a function of the integrated light energy and wherein the apparatus further comprises means for controlling pixel integration during at least one of the first and second frames to reduce the effects of ambient light during pixel integration.
6. The apparatus according to claim 5, characterized in that the first light source is selected at the end of the first frame and the detector is controlled to integrate the light energy of the first source at the end of the first frame.
7. The apparatus according to claim 6, characterized in that the second light source is selected at the end of the second frame and the detector is controlled to integrate the light energy of the second source at the end of the second frame.
8. The apparatus according to claim 7, characterized in that the second light source is selected at the beginning of the second frame and the detector is controlled to integrate the light energy of the second source during the entire second frame.
9. The apparatus according to claim 8, characterized in that the pixels are arranged in multiple lines in the array and where the detector is scanned per pixel line, such that the effects of ambient light during the scan of the second frames are erased in all sequential pixel lines scanned from the detector.
10. 10. The apparatus according to claim 9, characterized in that the means for comparing the images comprises means for comparing each signal of each pixel in each scanned line of the detector to the same pixel signal of the next scanned line of the detector to minimize the effects of the ambient light during the second frame.
11. 11. The apparatus according to any of the preceding claims, characterized in that the first light source comprises a light emitting diode (LED) light source and the second light source comprises a laser line light source.
12. 12. The apparatus according to any of the preceding claims, characterized in that the light detector comprises a frame-coupled charge device (CCD) detector.
13. 13. A method for inspecting a container for variations that affect the commercial acceptance of the container, characterized in that it comprises the steps of: (a) alternatively directing first and second light energies of different character on a portion of the container; (b) obtaining first and second two-dimensional images of the portion of the container illuminated in step (a) during illumination by the first and second light energies respectively and (c) detecting commercial variations in the container that affect the optical properties of the container by comparison of the first and second images.
14. The method-in accordance with claim 13, characterized in that step (b) comprises the steps of: (bi) directing the first and second light energies alternatively in a single area array detector to develop two-dimensional images of the Illuminated portion of the vessel in the detector and explore the two-dimensional images of the detector.
15. The method according to claim 1 or 2, characterized in that step (c) comprises the step of comparing the two-dimensional images associated with the first and second light energies.
16. 16. The method of compliance with the claim 15, characterized in that the step of comparing the images is carried out by superimposing the images.
17. 17. The method of compliance with the claim 16, characterized in that the step of superimposing the images is carried out by using one of the images to predict areas of presence of variations in the other of the images.
18. 18. The method according to any of the preceding claims, characterized in that the step (bii) is carried out when: (biia) controlling the detector in sequential scan frames of equal duration, (biib) directing the first and second energies light to the vessel during first and second sequential scan frames in the detector and (biic) scan the detector during the first and second scan frames to obtain the two-dimensional images.
19. 19. The method according to the claim 18, characterized in that step (a) comprises the steps of: (ai) selecting a first light source to direct the first light energy to the container during the first frame and (aii) selecting a second light source to direct the second light energy to the container during the second frame.
20. The method according to claim 19, characterized in that the first light source is selected at the end of the first frame and the second light source is selected at the beginning of the second frame.
21. 21. The method according to the claim 19, characterized in that the area array detector has a plurality of individual detector pixels adapted to integrate the incident light energy thereon and to provide pixel signals as a function of such integrated light energy and wherein the stage (b) ) comprises the additional step of: (biii) controlling pixel integration during at least one of the first and second frames 4 to reduce the effects of ambient light during pixel integration.
22. 22. The method of compliance with the claim 21, characterized in that the first light source is selected in step (ai) at the end of the first frame and the detector is controlled in step (biii) to integrate the light energy of the first source at the end of the first frame.
23. The method according to claim 22, characterized in that the second light source is selected in step (aii) at the end of the second frame and the detector is controlled in step (biii) to integrate the light energy of the second source at the end of the second frame.
24. 24. The method of compliance with the claim 22, characterized in that the second light source is selected in step (aii) at the beginning of the second frame and the detector is controlled in step (biii) to integrate the light energy of the second source during the entire second frame.
25. 25. The method according to claim 24, characterized in that the pixels are arranged in multiple lines in the array and where the detector is scanned in the stage (biic) per pixel line, such that the effects of light environment during scanning of the second frame are erased in all sequential pixel lines scanned from the detector.
26. The method according to claim 25, characterized in that step (c) comprises the step of comparing each signal of each pixel on each scanned line of the detector with the same pixel signal of the next scanned line of the detector to reduce the effects of ambient light during the second frame.
27. 27. The method according to any of the preceding claims 13-26, for inspecting a sealing surface of the container, characterized in that the first light source is such as to obtain in the detector a two-dimensional image of reflected light energy of the sealing surface against a dark background and the second light source is such as to obtain in the detector a two-dimensional image of the light energy reflected from the high points on the sealing surface against a dark background.
28. 28. The method according to any of the preceding claims 13-27, characterized in that it comprises the additional step of (d) moving the container in relation to the light sources and the detector and wherein the step (b) is carried out in increments of container movement.
29. 29. The method according to claim 28, characterized in that step (c) comprises the step of rotating the container about its axis.
30. 30. The method according to claim 28, characterized in that step (d) comprises the step of moving the container in a direction transverse to its axis.