US5452338A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method and system for real time offset correction in a large area solid state x-ray detector
Assignee: General Electric Co
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Filing: 1994-07-07
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Granted: 1995-09-19
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Expires: 2014-07-07
Abstract
Abstract Offset signals are removed from an incoming x-ray image produced by a large area solid state x-ray detector. A sequence of incoming dark images from the detector, when the detector is not exposed to x-rays, is recursively filtered to generate a low-noise, continuously-updated offset image. This low-noise continuously-updated offset image is stored in an offset image memory. The image in memory is subtracted from the incoming x-ray image to create a corrected image when the detector is exposed to x-rays.
Inventors
- 👤 Paul R. Granfors
- 👤 Jean-Claude Morvan
- 👤 Michael A. Juhl
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 19:40
CPC Classifications
H; H04; H04N; H04N5/00; H04N5/30; H04N5/32; H04N5/3205; H04N23/00; H04N23/30; H04N25/00; H04N25/60; H04N25/67; H04N25/671; H04N25/673; H05; H05G; H05G1/00; H05G1/08; H05G1/60
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
88 words
A method for removing offset signals from an incoming x-ray image produced by a large area solid state x-ray detector, comprising the steps of: recursively filtering a sequence of incoming dark images from the detector, when the detector is not exposed to x-rays, to generate a low-noise, continuously-updated offset image; storing the low-noise continuously-updated offset image in an offset image memory; subtracting the image in memory from the incoming x-ray image to create a corrected image with the offset signals removed, when the detector is exposed to x-rays.
Claim 2
Independent Claim
88 words
A method for removing offset signals from an incoming x-ray image produced by a large area solid state x-ray detector, comprising the steps of: recursively filtering a sequence of incoming dark images from the detector, when the detector is not exposed to x-rays, to generate a low-noise, continuously-updated offset image; storing the low-noise continuously-updated offset image in an offset image memory; subtracting the image in memory from the incoming x-ray image to create a corrected image with the offset signals removed, when the detector is exposed to x-rays.
Claim 3
Dependent Claim
42 words
A method for continuously updating an offset image as claimed in claim 1 further comprising the step of combining subsequent incoming dark images with the low-noise continuously-updated offset image in the offset image memory, when the detector is not exposed to x-rays.
Claim 4
Dependent Claim
90 words
A method for continuously updating an offset image as claimed in claim 1 wherein the step of recursively filtering a sequence of incoming dark images comprises the steps of: multiplying pixel values in an image from the sequence of incoming dark images by a multiplier of 1/n to generate first multiplied values; multiplying pixel values stored in the offset image memory by a multiplier of (1-1/n) to generate second multiplied values; adding the first and second multiplied values and generating output pixel values for storage in the offset image memory.
Claim 5
Dependent Claim
32 words
A method for continuously updating an offset image as claimed in claim 3 wherein the value of n controls amount of noise reduction and speed of updating of the offset image memory.
Claim 6
Independent Claim
90 words
A system for removing offset signals from an incoming x-ray image produced by a large area solid state x-ray detector, comprising: a recursive filter for filtering a sequence of incoming dark images from the detector, when the detector is not exposed to x-rays, to generate a low-noise, continuously-updated offset image; an offset image memory for storing the low-noise continuously-updated offset image; means for subtracting the image in memory from the incoming x-ray image to create a corrected image with the offset signals removed, when the detector is exposed to x-rays.
Claim 7
Independent Claim
90 words
A system for removing offset signals from an incoming x-ray image produced by a large area solid state x-ray detector, comprising: a recursive filter for filtering a sequence of incoming dark images from the detector, when the detector is not exposed to x-rays, to generate a low-noise, continuously-updated offset image; an offset image memory for storing the low-noise continuously-updated offset image; means for subtracting the image in memory from the incoming x-ray image to create a corrected image with the offset signals removed, when the detector is exposed to x-rays.
Claim 8
Dependent Claim
41 words
A system for continuously updating an offset image as claimed in claim 5 further comprising means for combining subsequent incoming dark images with the low-noise continuously-updated offset image in the offset image memory, when the detector is not exposed to x-rays.
Claim 9
Dependent Claim
45 words
A system for continuously updating an offset image as claimed in claim 6 wherein the means for combining subsequent incoming dark images with the low-noise continuously-updated offset image in the offset image memory, when the detector is not exposed to x-rays, comprises the recursive filter.
Claim 10
Dependent Claim
90 words
A system for continuously updating an offset image as claimed in claim 7 wherein the recursive filter comprises: a first multiplier for multiplying pixel values in an image from the sequence of incoming dark images by a multiplier of 1/n to generate first multiplied values; a second multiplier for multiplying pixel values stored in the offset image memory by a multiplier of (1-1/n) to generate second multiplied values; an adder for adding the first and second multiplied values and generating output pixel values for storage in the offset image memory.
Claim 11
Dependent Claim
31 words
A system for continuously updating an offset image as claimed in claim 8 wherein the value n controls amount of noise reduction and speed of updating of the offset image memory.
References Cited (Backward Citations)
US5038369A
Cited
US5296937A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1998-09-18 | 1999-03-20 | 1999-09-19 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2002-09-18 | 2003-03-20 | 2003-09-19 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2006-09-18 | 2007-03-20 | 2007-09-19 | $7700.00 | Window Closed / Lapsed |