DIGITAL RADIOGRAPHY DETECTOR IMAGE READOUT SYSTEM AND PROCESS

• US 20150131785A1
• Filed: 11/06/2014
• Published: 05/14/2015
• Est. Priority Date: 11/08/2013
• Status: Active Grant

• Current Assignee: CareStream Health Incorporated
• Original Assignee: CareStream Health Incorporated
• Inventors: Topfer, Karin, Hawver, Jeffrey R., DeHority, John
• Granted Patent: US 10,039,516 B2
• Time in Patent Office: Days
• US Class Current: 378/98
• CPC Class Codes: A61B 6/4233 using matrix detectors
• CPC Class Codes: A61B 6/5205 involving processing of raw data to produce diagnostic data
• CPC Class Codes: A61B 6/5258 involving detection or reduction of artifacts or noise
• CPC Class Codes: G06T 2207/10116 X-ray image
• CPC Class Codes: G06T 2207/20182 Noise reduction or smoothing in the temporal domain; Spatio-temporal filtering
• CPC Class Codes: G06T 5/70 Denoising; Smoothing
• CPC Class Codes: H04N 25/626 Reduction of noise due to residual charges remaining after image readout, e.g. to remove ghost images or afterimages
• CPC Class Codes: H04N 25/63 applied to dark current
• CPC Class Codes: H04N 5/32 Transforming X-rays cameras or camera modules for generating image signals from X-rays H04N23/30; circuitry of SSIS for transforming X-rays into image signals H04N25/30

Abstract

A radiographic imaging system and digital detector detect extraneous signals during DR detector image readout and compensate or remove extraneous signal artifacts from radiographic images. Novel capture and post processing procedures prevent undesirable noise artifacts from appearing in final radiographic images.

Claims

1. A method of image correction for a digital radiographic detector, the method comprising:

obtaining at least one dark frame;

obtaining at least one dark leakage frame, wherein the at least one dark leakage frame is different from the at least one dark frame;

obtaining at least one image data frame;

obtaining at least one exposure leakage frame;

obtaining at least one image lag data frame;

dark correcting the at least one image data frame and the at least one image lag data frame using the at least one dark frame;

dark correcting the at least one exposure leakage frame using the at least one dark leakage frame;

correcting the at least one dark corrected image lag data frame with a noise correction process;

correcting the at least one dark corrected exposure leakage frame with the noise correction process; and

combining the noise corrected, dark corrected at least one exposure leakage frame, the at least one noise corrected, dark corrected image lag data frame, and the at least one dark corrected image data frame to obtain a corrected image frame.

2. The method of claim 1, further comprising continuously averaging N dark frames to obtain the at least one dark frame, where N is an integer greater than 1, and continuously averaging M dark leakage frames to obtain the at least one dark leakage frame, where M is an integer greater than 1.

3. The method of claim 1, wherein the at least one image data frame is each frame wherein an X-ray beam is incident on the detector and a single succeeding image data frame.

4. The method of claim 1, further comprising correcting the at least one dark corrected image lag data frame with a first noise correction process and correcting the at least one dark corrected exposure leakage frame with a second noise correction process, and wherein the second noise correction process is different from the first noise correction process

5. The method of claim 4, wherein the first noise correction process and the second noise correction process are related to a SNR, responsive to a SNR or proportional to a SNR, related to an image content amount, responsive to the image content amount or proportional to the image content amount.

6. The method of claim 1, further comprising correcting a pre-exposed portion, an exposed portion and a post-exposed portion of the dark corrected at least one exposure leakage frame.

7. The method of claim 1, wherein the at least one image data frame comprises an X-ray beam start or comprises the X-ray beam start and X-ray beam stop.

8. The method of claim 1, wherein the combining comprises adding the at least one noise corrected, dark corrected image lag data frame and the at least one dark corrected image data frame to obtain a corrected image frame while subtracting the noise corrected, dark corrected at least one exposure leakage frame.

9. The method of claim 1, further comprising applying gain and defect correction to the corrected image frame.

10. The method of claim 1, further comprising generating in real time the corrected image frame or processing the corrected image frame at the detector.

11. The method of claim 1, further comprising obtaining row by row from the detector the at least one dark frame, the at least one dark leakage frame, the at least one image data frame, the at least one exposure leakage frame and the at least one image lag data frame.

12. A method of image correction for a digital radiographic detector, the method comprising:

obtaining at least one dark frame;

obtaining at least one dark leakage frame, wherein the at least one dark leakage frame is different from the at least one dark frame;

obtaining at least one image data frame;

obtaining at least one exposure leakage frame;

dark correcting the at least one image data frame using the at least one dark frame;

dark correcting the at least one exposure leakage frame using the at least one dark leakage frame; and

combining the dark corrected at least one exposure leakage frame and the at least one dark corrected image data frame to obtain a corrected image frame.

13. The method of claim 12, further comprising identifying in real time at least three of the at least one dark frame, the at least one dark leakage frame, the at least one image data frame, and the at least one exposure leakage frame.

14. The method of claim 12, further comprising determining x-ray beam on or x-ray beam off using frame-to-frame comparison of the same row.

15. The method of claim 12, further comprising determining x-ray beam off using differences between two image data frames or between two exposure leakage frames.

16. A method of image correction for a digital radiographic detector, the method comprising:

obtaining at least one dark corrected image data frame;

obtaining at least one dark corrected exposure leakage frame; and

combining the at least one exposure leakage frame, and the at least one image data frame to obtain a corrected image frame.

17. The method of claim 16, further comprising:

correcting the at least one dark corrected exposure leakage frame with a noise correction process; and

combining the noise corrected, dark corrected at least one exposure leakage frame to obtain the corrected image frame.

18. The method of claim 16, further comprising obtaining at least one dark corrected image lag data frame, and wherein the combining comprises combining the at least one dark corrected image lag data frame to obtain the corrected image data frame.

19. The method of claim 16, further comprising determining x-ray beam on or x-ray beam off using frame-to-frame comparison of the same row.

20. The method of claim 16, further comprising applying gain and defect correction to the corrected image frame.