X-ray automatic synchronous inspection system

• US 5,097,494 A
• Filed: 10/05/1989
• Issued: 03/17/1992
• Est. Priority Date: 12/09/1985
• Status: Expired due to Fees

• Current Assignee: X-Ray Industries, Inc. (Applus Services SA)
• Original Assignee: X-Ray Industries, Inc. (Applus Services SA)
• Inventors: Bergeron, Mark M., Schreckendgust, Jay G., Pantelleria, James B.
• Primary Examiner(s): Westin, Edward P.
• Assistant Examiner(s): WONG, DON KITSUN
• Application Number:
  US07/417,367
• Time in Patent Office: 894 Days
• Field of Search: 378/91, 378/95, 378/97, 378/98, 378/101, 378/109, 378/110, 378/57, 378/56, 378/68, 378/4, 378/8, 378/10, 378/108
• US Class Current: 378/110
• CPC Class Codes: G11B 15/67565 of the cassette with holder

Abstract

An X-ray inspection apparatus and method allow inspection of the contents of containers moving rapidly past an inspection station. The system includes an X-ray source pulsed by control logic, an image amplifier for converting an X-ray image of the container contents to a visible image and a solid-state camera for converting the visible image into video signals which are processed by a computer-controlled image processor. Clear images are produced of the contents of rapidly moving containers by pulsing the X-ray source. Control logic and a reject mechanism eject containers having foreign contaminants. Image illuminance stability is enhanced by feedback signals from the vision computer which operate a motorized camera lens.

Claims

1. X-ray inspection apparatus% of the type having an X-ray source for inspecting the contents of each of a plurality of containers moving through an inspection station, comprising:

means for generating a position signal related to the movement of one of said containers through said inspection station;

circuit means responsive to said position signal for generating a trigger signal;

means responsive to said trigger signal for generating a control signal possessing a waveform having a predefined amplitude contour which is used to control the intensity of radiation emitted from said X-ray source;

means coupled to said circuit means for controlling electrical current delivered through said X-ray source in proportion to the amplitude contour of said control signal, said current through said X-ray source causing said X-ray source to irradiate said container with X-rays and creating an X-ray image of the contents of said container;

means for capturing said X-ray image; and

means coupled with said capturing means for analyzing said X-ray image.

2. The apparatus of claim 1, wherein said control signal generating means is coupled between said circuit means and said electrical current controlling means.

3. The apparatus of claim 2, including a source of DC power, and wherein said electrical current is a direct current produced by said DC power source.

4. The apparatus of claim 3, further including means coupled to said central signal generating means for controlling a direct current delivered through said X-ray source and produced by said source of DC power in inverse to the amplitude contour of the signal generated said control signal generating means.

5. The apparatus of claim 4, further including means for enabling said proportional current controlling means and said inversely proportional current controlling means.

6. The apparatus of claim 5, wherein said enabling means alternates in response to the position signal between enabling said proportional current controlling means and enabling said inversely proportional current controlling means.

7. The apparatus of claim 1, wherein said capturing means includes a camera for recording said X-ray image and a light restriction means disposed in the optical path of said camera for restricting the intensity of said X-ray image captured by said camera.

8. The apparatus of claim 7, wherein said analyzing means derives a brightness correction value by comparing a value proportional to the brightness of said captured X-ray image to a preselected value.

9. The apparatus of claim 8, wherein said analyzing means converts said brightness correction value into a first set of pulses when said X-ray image brightness value is above said preselected value and converts said brightness correction value into a second set of pulses when said X-ray image brightness value is below said preselected value.

10. A method of inspecting the contents of each of a plurality of containers moving through an inspection station, comprising the steps of:

(A) sensing the presence of a container moving through said inspection station;

(B) generating, in response to sensing a container in step (A), a waveform having a predefined amplitude contour;

(C) controlling a direct current delivered to an X-ray source in proportion to the amplitude contour of the waveform generated in step (B), said direct current causing said X-ray source to irradiate the container sensed in step (A) with X-rays, thereby creating an X-ray pattern representing the contents of said container;

(D) capturing said X-ray pattern; and

(E) analyzing said X-ray pattern.

11. The method of claim 10, further including the steps of:

(F) comparing the intensity of said X-ray pattern to a preselected intensity level; and

(G) limiting the amount of radiation in the X-ray pattern which is captured in step (D) based on the comparison performed in step (F).

12. The method of claim 11, further including the step of controlling, in alternating sequence with step (C), a direct current through said X-ray source in inverse proportion to the amplitude contour of the waveform generated in step (B).

13. The method of claim 12, wherein said alternating between said current proportional to said waveform contour generated in step (B) and said current inversely proportional to said waveform contour is a function of the container sensed in step (A).

14. X-ray apparatus for inspecting the contents of a plurality of moving containers moving through an inspection station, comprising:

means for detecting the of one of said containers at said inspection station;

a trigger circuit responsive to said detecting means for generating a trigger pulse;

a pulse generating circuit responsive to said trigger pulse for generating a control pulse having a predefined amplitude contour;

an X-ray generating means responsive to said amplitude contour of said control pulse for irradiating one of said containers with X-rays to produce an X-ray image of said container, wherein the intensity of said X-rays is directly related to the amplitude contour of said control pulse;

means for capturing the X-ray image;

processor means coupled with said capturing means for analyzing the X-ray image to determine the contents of said container; and

an adjustable iris disposed in the optical path of said camera and responsive to a command signal from said processor for attenuating the intensity of the X-ray image received by said capturing means.

15. The apparatus of claim 14, wherein said X-ray generating means further includes a first and second amplifier responsive to the amplitude contour of the control pulse and an X-ray source coupled to said first and second amplifier.

16. The apparatus of claim 15, wherein said first amplifier further includes a first enabling circuit coupled with a first power transistor circuit and said second amplifier further includes a second enabling circuit coupled with a second power transistor circuit, said first and second enabling circuits responsive to said triggering means for alternatively enabling said first and second power transistor circuits.

17. The apparatus of claim 16, wherein said X-ray generating means further includes a direct current source of electrical power and said first amplifier controls the direct current through said X-ray source in direct proportion to the amplitude contour of the control pulse, and said second amplifier controls the direct current through said X-ray source in inverse proportion to the amplitude contour of the control pulse.

18. The apparatus of claim 14, wherein said adjustable iris includes a stepper motor.

19. The apparatus of claim 14, wherein said pulse generator includes an op-amp configured with a twin-tee feedback network.

20. The apparatus of claim 14, comprising means for limiting the duration of the control pulse to between 0.1 and 10 milliseconds.