X-ray generating apparatus and associated method

• US 5,202,932 A
• Filed: 08/20/1991
• Issued: 04/13/1993
• Est. Priority Date: 06/08/1990
• Status: Expired due to Fees

• Current Assignee: Cintex of America
• Original Assignee: Catawa Pty Limited
• Inventors: Pasiak, David, Cambier, James L.
• Primary Examiner(s): Moore, David K.
• Assistant Examiner(s): Fox, David
• Application Number:
  US07/750,450
• Time in Patent Office: 602 Days
• Field of Search: 378/95, 378/57, 378/58, 378/101-107, 382/8, 382/47, 382/34, 382/56, 358/106, 356/237
• US Class Current: 382/142
• CPC Class Codes: G01N 23/043 using fluoroscopic examination, with visual observation or video transmission of fluoroscopic images
• CPC Class Codes: G01V 5/22 Active interrogation, i.e. by irradiating objects or goods using external radiation sources, e.g. using gamma rays or cosmic rays
• CPC Class Codes: H05G 1/26 Measuring, controlling or protecting measuring X-ray radiation G01T
• CPC Class Codes: H05G 1/56 Switching-on; Switching-off
• CPC Class Codes: H05G 1/60 Circuit arrangements for obtaining a series of X-ray photographs or for X-ray cinematography

Abstract

An X-ray generator and associated method are disclosed. The X-ray generator and method are provided for inspection of objects which are conveyed into an inspection station which includes an X-ray device and image processing device. The X-ray device directs high-energy, short-pulse X-rays toward an object as the object moves into a desired position. This X-ray radiation is received by a video camera and the resulting image is then digitized and transmitted to an image processing device which analyzes the information and determines whether or not the object conforms to a predetermined standard threshold. One aspect of the apparatus includes a rejection device which will remove objects which do not pass inspection thresholds.

Claims

1. A method of inspecting an object comprising the steps of

generating an external signal in response to said object being in a predetermined optimal position;

generating a high energy short x-ray pulse in response to said external signal and causing said x-ray pulse to impinge upon said object to provide information for creating an x-ray image of said object;

converting x-ray radiation passing through said object into a visible light image;

converting said visible light image into digital image information;

resampling said digital image information by selecting minimum pixel intensity values from a plurality of pixel portions of said digital image signal;

analyzing said digital image information using a pixel-by-pixel comparison of said signal to a predetermined condition and determining whether a departure from said condition has occurred

analyzing said digital image information using the steps of

selecting said minimum pixel intensity values from a plurality of pixel blocks of said digital image information;

using said selected minimum pixel intensity values to represent said digital image information in said resampled output image;

convolving said resampled output image with a first mask to enhance irregularities;

convolving said resampled and enhanced output image with a second mask to reduced noise;

searching said resampled and enhanced output image to find an overall minimum pixel intensity value;

comparing said overall minimum pixel intensity value of said resampled output image with a predetermined threshold value; and

generating a command signal responsive to said comparison of said overall minimum pixel intensity value with said threshold value.

2. The method of claim 1 including selecting said predetermined threshold value for said overall minimum pixel intensity value by

processing a predetermined number of known acceptable objects, and determining a minimum value for each, and

performing a statistical analysis of said minimum values, and selecting a predetermined threshold value based upon said statistical analysis.

3. The method of claim 1, including conveying a plurality of objects in sequence and continuously generating and directing said x-ray pulses toward and impinging said pulses upon said objects and effecting said analyzing of said digital image with digital information representative of each said object.

4. The method of claim 3, including

generating and directing said X-ray pulses at said objects when said objects are in a position to receive said X-ray pulse.

5. The method of claim 1, including

generating said X-ray pulses each having a duration of between about 0.5 and 5.0 milliseconds.

6. The method of claim 1, including

selecting as said first mask to enhance irregularities a mask having dimensions of between about 1×

1 to 5×

5.

7. The method of claim 1, including

selecting as said second mask to reduce noise a mask having dimensions of between about 1×

1 to 5×

5.

8. A method of inspecting an object comprising the steps of

generating an external signal in response to said object being in a predetermined optimal position;

generating a high energy short x-ray pulse in response to said external signal and causing said x-ray pulse to impinge upon said object to create an x-ray image of said object;

converting said x-ray image into a digital output image;

convolving said output image with at least one mask;

searching said output image to find an overall minimum pixel intensity value;

comparing said overall minimum pixel intensity value of said output image with a predetermined threshold value and generating a responsive signal when the comparison results in the conclusion that a departure from said predetermined threshold value has been sensed.

9. The method of claim 8 including

convolving said output image with a first mask to enhance irregularities;

and

convolving said enhanced output image with a second mask to reduce electrical noise.

10. The method of claim 8 including

selecting minimum pixel intensity values from a plurality of pixel blocks of said digital output image;

and

using said selected minimum pixel intensity values to represent said digital image information in a resampled output image.

11. The method of claim 8 including selecting said predetermined threshold value for said overall minimum pixel intensity value by

processing a predetermined number of known acceptable objects, and determining a minimum value for each, and

performing a statistical analysis of said minimum values, and selecting a predetermined threshold value based upon said statistical analysis.

12. The method of claim 10, including

conveying a plurality of objects in sequence and continuously generating and directing said x-ray pulses toward and impinging said pulses upon said objects and analyzing digital image information representative of each said object.

13. The method of claim 12, including

generating and directing said x-ray pulses at said objects when said objects are in a position to receive said x-ray pulse.

14. The method of claim 8, including

generating said x-ray pulses each having a duration of between about 0.5 and 5.0 milliseconds.

15. The method of claim 9, including

selecting as said first mask to enhance irregularities a mask having dimensions of between about 1×

1 to 5×

5.

16. The method of claim 9, including

selecting as said second mask to reduce noise a mask having dimensions of between about 1×

1 to 5×

5.