Apparatus for inspecting containers having a dual optical transmission means, a dual light sensing means and a rotating head

Apparatus for inspecting containers that includes an inspection head positioned for rotation about a fixed axis adjacent to a container under inspection. A light source and a camera are carried by the head for directing illumination energy onto the container and receiving energy from the container after interaction with the container. The camera is connected to interface electronics for controlling camera operation and receiving data signals from the camera. The light source, camera and interface electronics are mounted on the head and rotate continuously, with the light source and interface electronics being connected by optical commutation to external control devices.

The present invention is directed to optical imaging apparatus having 
particular utility for inspection of containers, and more particularly to 
an apparatus and method for inspecting containers for commercial 
variations and other characteristics. 
BACKGROUND OF THE INVENTION 
Conventional technology for mass production of glass or plastic containers 
involves forming the containers in a multiplicity of molds. Various types 
of faults or checks, termed "variations" in the art, may occur. Variations 
that may affect commercial acceptability of the containers are called 
"commercial variations." It has heretofore been proposed to employ optical 
scanning techniques for inspecting such containers for variations that 
affect optical transmission characteristics of the containers. In U.S. 
Pat. Nos. 4,378,493, 4,378,494 and 4,378,495, all assigned to the assignee 
hereof, there are disclosed methods and apparatus in which glass 
containers are conveyed through a plurality of stations where they are 
physically and optically inspected. At one inspection station, a glass 
container is held in vertical orientation and rotated about its vertical 
axis. An illumination source directs diffused light energy through the 
container sidewall. A camera, which includes a plurality of light 
sensitive elements or pixels oriented in a linear array parallel to the 
vertical axis of rotation, is positioned to view light transmitted through 
a vertical strip of the container sidewall. The output of each pixel is 
sampled at increments of container rotation, and event signals are 
generated when adjacent pixel signals differ by more than a preselected 
threshold level. An appropriate reject signal is produced and the rejected 
container is sorted from the conveyor line. 
U.S. Pat. No. 4,701,612, assigned to the assignee hereof, discloses a 
method and apparatus for inspecting the finish of transparent containers, 
particularly glass containers, that include facility for directing 
diffused light energy laterally through the container finish as the 
container is rotated about its central axis. A camera includes a plurality 
of light sensitive elements or pixels disposed in a linear array angulated 
with respect to the container axis and coplanar therewith to view the 
external and internal finish wall surfaces, the latter through the open 
container mouth. Individual elements of the camera linear array are 
sampled by an information processor at increments of container rotation, 
and corresponding data indicative of light intensity at each element is 
stored in an array memory as a combined function of element number and 
scan increment. Such data is compared, following completion of container 
rotation, to standard data indicative of an acceptable container finish, 
and a reject signal is generated if such comparison exceeds an 
operator-adjustable threshold. 
U.S. Pat. No. 4,945,228, assigned to the assignee hereof, discloses a 
system for inspecting the finish of a container by directing light energy 
downwardly onto the container finish as the container is rotated, and 
receiving reflections from the container finish as a function of its 
structural characteristics and variations. A light source is positioned to 
direct light energy onto the container sealing surface as the container is 
held in stationary position and rotated about its central axis. A camera 
includes an array of light sensitive elements positioned and oriented with 
respect to the container axis of rotation to receive light energy 
reflected by the sealing surface. The camera array is scanned at 
increments of container rotation to develop information indicative of 
light intensity at each array element as a function of such increments, 
and commercial variations at the container sealing surface are detected as 
a function of such information. 
U.S. Pat. No. 4,958,223, also assigned to the assignee hereof, discloses 
apparatus for inspecting the finish of a container as the container is 
rotated about its central axis. A light source is positioned to direct 
diffused light energy onto the container finish, and a camera is 
positioned across the axis of the container from the light source. The 
camera comprises multiple arrays of light sensitive elements positioned 
with respect to the camera focusing elements on a common optical plane 
opposed to the light source to receive non-overlapping images of the 
container finish spaced from each other laterally of the container axis. 
Information processing electronics are coupled to the camera arrays for 
indicating optical characteristics of the container finish as differing 
functions of light intensity incident on the elements of each array. 
Systems of the type disclosed in the noted patents have enjoyed substantial 
commercial success in conjunction with cylindrical containers that are 
symmetrical about their axes, but are not as well adapted for use in 
conjunction with non-circular containers such as salad dressing bottles. A 
general object of the present invention is to provide an apparatus and 
method for inspecting containers that are adapted to operate in 
conjunction with containers of any shape, including both round and 
non-round containers, and containers of any size or geometry. Another 
object of the present invention is to provide an apparatus and method of 
the described character that are adapted for inspecting any portion of a 
container--i.e., either the container body, the container finish or both. 
SUMMARY OF THE INVENTION 
Apparatus for inspecting containers in accordance with the present 
invention includes an inspection head for rotation about a fixed axis 
adjacent to, preferably coaxial with, a container. A light transmitter and 
a light receiver are carried by the head and oriented for directing 
illumination energy onto a container disposed adjacent to the head, and 
receiving at least a portion of such illumination energy following 
interaction with the container. Information processing electronics are 
coupled to the light receiver for detecting commercial variations in the 
container as a function of the optical characteristics thereof. Rotation 
of the head, and of the optical transmitter and receiver carried thereby, 
eliminates any need for rotating the container, which may thus be held in 
fixed position coaxial with the axis of rotation of the inspection head. 
In accordance with the preferred embodiment of the invention, a light 
source is disposed in fixed position adjacent to the head, and a first 
optical transmitter on the head is aligned with the light source for 
receiving illumination light energy from the source and projecting such 
energy onto the container. A first light sensor or detector on the head 
receives a portion of the light energy following interaction with the 
container, and generates first electrical signals as a function thereof. A 
second light transmitter on the head is responsive to such electrical 
signals for generating light energy, and a second light sensor is disposed 
in fixed position adjacent to the head in alignment with the second 
transmitter for receiving light energy generated by the second transmitter 
and generating corresponding second electrical signals as a function 
thereof. The information processing electronics is responsive to such 
second electrical signals for detecting commercial variations in the 
container. Thus, in accordance with this particular aspect of the 
invention, the head is continuously rotated about its axis, and all 
communications to and from the head components are accomplished by means 
of commutated light energy, thereby eliminating any need for electrical 
brushes or the like to transmitting signals to and from the optics on the 
rotating head. 
In accordance with another aspect of the invention in the first embodiment 
thereof, interface electronics is carried by the rotating head for 
receiving and processing the signals from the first detector. Interface 
control signals generated by the information processor are coupled to the 
interface electronics carried by the head through a third light 
commutator, again eliminating any need for electrical brushes or the like. 
In the preferred embodiment exemplifying this aspect of the invention, the 
interface electronics includes an annular array of light transmitters and 
receivers at fixed radius with respect to the axis of head rotation. An 
annular fiber optic array is aligned with the array of transmitters and 
receivers coaxial with the axis of rotation, and is connected to the 
information processor. Thus, the annular fiber optic array carries 
bidirectional communication between the information processor and the 
interface electronics for controlling operation of the latter, and between 
the interface electronics and the information processor for transmitting 
signals indicative of optical characteristics of the container.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
FIGS. 1-6 illustrate an apparatus or station 10 for inspecting the finish 
12 of glass containers 14. The term "container finish" generally refers to 
that portion of the container that defines the container mouth. In a glass 
bottle, for example, the finish includes that portion of the container 
neck having threads and/or shoulders for receiving the container cap, as 
well as the upper surface of the neck surrounding the container mouth 
against which the cap seats and seals. Containers 14 are presented in 
sequence by a suitable conveyor 16 (FIG. 6), and are held stationary at 
station 10 during the inspection process. Presence of a container 14 at 
station 10 is detected by a switch or the like 17 (FIG. 7). 
The inspection apparatus includes a head 18 carried within a support 
bracket or collar 20 by spaced roller bearings 22, and coupled by a belt 
24 to an electric motor 26 for continuous rotation at constant speed about 
the axis 40 of head 18. Head 18 includes a hollow generally cylindrical 
collar 28 carried by bearings 22, and a radially extending flange or 
platen 30 disposed beneath support 20. A circumferential array of up to 
four optical fibers 32,34,36,38 extend through the hollow interior of head 
collar 28. At their upper ends, and as best seen in FIG. 2, the four 
optical fibers 32-38 terminate in a plane perpendicular to the axis 40 of 
rotation. Fiber 34 extends from the lower end of collar 28 along the 
underside of platen 30, and is operatively coupled to a projection lens 
system 42 carried beneath platen 30. Fibers 32 and 36-38 are orovided for 
later addition of projection lenses, if desired. Fibers 32-38 may be 
unitary fibers, or bundles of fibers. 
A camera 44 is also carried beneath platen 30. Lens system 42 and camera 44 
are mounted beneath platen 30 by the respective brackets 46,48. Each 
bracket 46,48 is mounted by a screw 50 beneath platen 30 for angular 
adjustment about axis 40. Lens system 42 and camera 44 are mounted to 
their respective brackets 46,48 by adjustable fittings 52 for angular 
adjustment in planes parallel to the axis of rotation of head 18. Thus, 
both lens system 42 and camera 44 are fully adjustable with respect to 
each other and with respect to containers 12 positioned therebeneath. In 
the particular arrangement shown in FIG. 1, lens system 42 is oriented to 
direct an illumination beam onto the exterior surface of the container 
finish 12, and camera 44 is diametrically opposed to lens system 42 for 
receiving reflections and refractions from the container finish. These 
lens and camera orientations are by way of example only. Camera 44 may 
comprise a single photocell, a linear array or line scan camera, or a 
matrix array sensor scanned by row and column. These types of cameras are 
exemplified by the patents noted above, and the particular type of camera 
44 employed is not per se part of the present invention. 
An interface electronics assembly 54 is mounted by a bracket 56 at the 
upper end of head collar 28 above support 20 for rotation with the collar 
and head. An electrical cable 58 connects interface electronics 54 with 
camera 44 for conveying control signals to the camera (if required) and 
obtaining data signals from the camera. A circuitboard assembly 60 is 
mounted by stand-offs 62 above the main interface electronics board. 
Circuitboard 60 includes an annular or circular array of plural light 
emitting diodes (LED's) 64 (FIG. 5) and photosensors 66. LED's 64 and 
photosensors 66 are disposed in a circular array at fixed radius from the 
axis of rotation 40. LED's 12 are connected to interface electronics 54 
for generating light signals under control of the electronics, and 
photosensors 66 are connected to the interface electronics for receiving 
and transmitting control signals to the interface electronics. 
A light source 68 is disposed in suitable fixed position spaced from 
rotating head 18. A cylindrical fiber optic cable or bundle 70 extends 
from light source 68 through a fixed support collar 74 into head collar 
28, and terminates in a plane spaced from and parallel to the planar ends 
of optical fibers 32-38. The diameter of fiber optic cable 70 is such as 
to overlie all of the ends of fibers 32-38, as best seen in FIG. 2. An 
annular fiber optic bundle 72 (FIGS. 1 and 5) is mounted by a bracket to 
fixed support collar 74, and opens in opposition to the circular array of 
LED's 64 and photosensors 66 at fixed radius from the axis of rotation. In 
the preferred embodiment illustrated in FIG. 1, the array of LED's and 
photosensors 64,66, and the annular fiber optic bundle 72, are at 
identical radius and axially opposed to each other. Fiber optic bundle 72 
is connected to information processing electronics 75. Annular bundle 72 
is of conventional type. The twelve LED's 64 and four photosensors 66 
illustrated in FIG. 5 (these numbers being by way of example only) are 
uniformly distributed about rotation axis 40. 
In operation of apparatus 10, best illustrated in the schematic diagram of 
FIG. 6, containers 14 are individually transported in sequence by conveyor 
16 and held in fixed position beneath head 18 coaxially with axis 40. 
Light from source 68 is transmitted along fiber optic cable 70 and 
radiated from the end thereof toward the four fiber optic bundles 32-38 
(FIG. 3). Fibers 32 and 36-38 are not employed in this embodiment of the 
invention. Light entering the upper end of fiber bundle 34 is conducted to 
lens system 42, which thus receives the illumination energy from light 
source 68 and projects such energy onto the finish 12 of container 14. 
Since the radius of fiber 34 from the axis of rotation is within the 
overall radius of fiber 70, such transmission of illumination energy is 
constant and continuous independent of rotation of head 28. Camera 44 
receives the illumination energy following interaction with container 14, 
and provides corresponding data signals along electrical cable 58 to 
interface electronics 54. 
The interface electronics process the camera data signals as appropriate. 
The circular array of LED's 64 and photosensors 66 cooperate with annular 
fiber optic bundle 72 to provide bidirectional data communication with 
information processor 75 through an optical communication coupler 73. That 
is, information processor 75 may download control and command signals to 
interface electronics 54 by means of LED 64 in coupler 73, fiber optic 72 
and photosensors 66 on board 60, and may receive data and other 
information from interface electronics 54 by means of LED's 64 on board 
60, fiber optic 72 and photosensor 66 in coupler 73. In this connection, 
it will be appreciated that disposition of the annular fiber optic bundle 
in axially aligned opposition to the circular array of LED's and 
photosensors provides for continuous bidirectional communication (in one 
direction at a time) independent of rotation of head 18 and the interface 
electronics. This provides a number of advantages. There is no need for 
variable resistors, capacitors or other adjustment means on interface 
electronics 54. All thresholds, parameters and other control information 
is sent from information processor 75. This permits adjustments to be made 
during operation--i.e., without terminating rotation of head 18. 
Electronic transmission and storage of control information also avoids 
instabilities due to vibration or the like. Exemplary details of interface 
electronics 54, information processor 75, and camera control and data 
handling algorithms are set forth in the above-noted patents, and do not 
per se form part of the present invention. 
FIG. 7 illustrates another system 80 in which the illumination light source 
42a comprises an electronically controlled light source directly connected 
by suitable electrical conductors to interface electronics 54a. Camera 44 
is also directly connected to interface electronics 54a, which is not 
mounted on head 18a. A finger 82 extends from the upper end of head 18a, 
and is positioned to engage at least one, and preferably a pair of 
angularly spaced limit switches 84,86. Limit switches 84,86 are connected 
to the control electronics for motor 26a. 
In operation, containers 14 are again conveyed in sequence and held beneath 
head 18 coaxially with axis 40. Head 18a and platen 30 rotate about axis 
40 back and forth between predetermined angular positions defined by the 
positions of limit switches 84,86 with respect to the axis of rotation. 
Light source 42a and camera 44 thus sweep the finish 12 of container 14 as 
head 18 is rotated. Since head 18a sweeps back and forth with respect to 
container 14, as distinguished from continuously rotating at constant 
speed in a given direction as in the embodiment of FIGS. 1-6, light source 
42a and camera 44 may be connected directly to electronics 54a rather than 
through light commutation arrangements as in the previous embodiment. 
Limit switches 84,86 preferably are adjustable for setting the angular 
limits of head rotation. More than one light source 42a and/or camera 44 
may be carried by platen 30. Preferably, rotation of head 18a is 
coordinated with intermittent motion of conveyor 16 so that head 18a 
sweeps in one direction for one container, stops as that container is 
removed and a new container is positioned, and then sweeps the second 
container in the reverse direction. 
Although the preferred embodiments of the invention have been illustrated 
and described hereinabove in connection with measuring optical 
characteristics of the finish 12 of containers 14, it will be appreciated 
that the basic principles of the invention can be applied equally as well 
to inspection of other portions of the container, such as the container 
shoulder and/or side wall, by repositioning or re-orienting the light 
source and camera so that the illumination beam of the light source and 
the field of view of the camera sweep the desired portion or portions of 
the container positioned at the inspection station.