US6370265B1
Expired / Lapsed
US
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Method for generating gray scale transfer functions for use in displaying a digital radiogram
Assignee: Direct Radiography Corp
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Filing: 1999-11-24
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Granted: 2002-04-09
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Expires: 2019-11-24
Abstract
Abstract A method for generating on demand a gray scale transfer curve for use in displaying an image comprised of a plurality of digital values representing pixel gray scale levels with a desired contrast and brightness. This is achieved by using a single sigmoid shaped function Y=f(X, a, b, c) resembling an H&D curve of a photographic film. The Y axis represents digital output values to be used in displaying an image, while the X axis represents input digital values representing captured image information. “a” is a number representing boundary conditions for X and Y, “b” is a first parameter controlling the location of the curve along the X axis and “c” is a second parameter controlling the slope of the curve slope. This function is used to derive a Look-Up-Table (LUT) representing a continuous GST curve having the desired contrast and brightness.
Inventors
- 👤 Jeffrey H. Bell
- 👤 Eric L. Gingold
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 12:55
CPC Classifications
G; G06; G06T; G06T5/00; G06T5/90; G06T5/92
Claims Analysis
Total Claims: 16
Claim 1
Independent Claim
131 words
A method for generating on demand a gray scale transfer (GST) curve for use in deriving a Look-Up-Table (LUT) for displaying an image comprised of a plurality of digital values representing pixel densities with a desired contrast and brightness, the method comprising using a single sigmoid function Y=f(X, a, b, c) wherein Y represents output values used in displaying an image, X represents input digital values representing captured image information, b=inv 1n (X max contrast *c) and is a first parameter controlling the location of the curve along the X axis, “c” is between 0.01% to 0.2% of X max value and is a second parameter controlling the curve slope and a=Y u *(1+b*e −cXu ) and wherein X u and Y u represent input and output digital data boundary conditions.
Claim 2
Independent Claim
131 words
A method for generating on demand a gray scale transfer (GST) curve for use in deriving a Look-Up-Table (LUT) for displaying an image comprised of a plurality of digital values representing pixel densities with a desired contrast and brightness, the method comprising using a single sigmoid function Y=f(X, a, b, c) wherein Y represents output values used in displaying an image, X represents input digital values representing captured image information, b=inv 1n (X max contrast *c) and is a first parameter controlling the location of the curve along the X axis, “c” is between 0.01% to 0.2% of X max value and is a second parameter controlling the curve slope and a=Y u *(1+b*e −cXu ) and wherein X u and Y u represent input and output digital data boundary conditions.
Claim 3
Independent Claim
135 words
A method for generating on demand a gray scale transfer (GST) curve for use in deriving a Look-Up-Table (LUT) for displaying an image comprised of a plurality of digital values representing pixel densities with a desired contrast and brightness, the method comprising using a single sigmoid function Y=f(X, a, b, c) wherein Y represents output values used in displaying an image, X represents input digital values representing captured image information, “b” is a first parameter controlling the location of the curve along the X axis, “c” is a second parameter controlling the curve slope and “a” is determined from boundary conditions wherein the function Y=f(X, a, b, c) is: Y=a/(1+b*e −cX ) where b=inv 1n (X max contrast *c); “c” is between 0.01% to 0.2% of X max value and: a=Y u *(1+b*e −cXu ).
Claim 4
Independent Claim
135 words
A method for generating on demand a gray scale transfer (GST) curve for use in deriving a Look-Up-Table (LUT) for displaying an image comprised of a plurality of digital values representing pixel densities with a desired contrast and brightness, the method comprising using a single sigmoid function Y=f(X, a, b, c) wherein Y represents output values used in displaying an image, X represents input digital values representing captured image information, “b” is a first parameter controlling the location of the curve along the X axis, “c” is a second parameter controlling the curve slope and “a” is determined from boundary conditions wherein the function Y=f(X, a, b, c) is: Y=a/(1+b*e −cX ) where b=inv 1n (X max contrast *c); “c” is between 0.01% to 0.2% of X max value and: a=Y u *(1+b*e −cXu ).
Claim 5
Dependent Claim
32 words
The method according to claim 1 wherein the parameters “b” and “c” are varied to produce a family of LUTs representing a family of GST curves having desired different contrast and brightness.
Claim 6
Dependent Claim
20 words
The method according to claim 2 wherein the input digital values for the X axis are normalized input digital values.
Claim 7
Dependent Claim
21 words
The method according to claim 4 wherein the output digital values from the Y axis are also normalized output digital values.
Claim 8
Dependent Claim
139 words
A program embodied in a machine readable medium for programming a control computer to generate on demand a gray scale transfer (GST) curve for use in deriving a Look-Up-Table (LUT) for displaying an image comprised of a plurality of digital values representing pixel densities with a desired contrast and brightness, using a single sigmoid function Y=f(X, a, b, c) wherein Y represents output values used in displaying an image, X represents input digital values representing captured image information, b=inv 1n (X max contrast *c) and is a first parameter controlling the location of the curve along the X axis, “c” is between 0.01% to 0.2% of X max value and is a second parameter controlling the curve slope and a=Y u *(1+b*e −cXu ) and wherein X u and Y u represent input and output digital data boundary conditions.
Claim 9
Dependent Claim
139 words
A program embodied in a machine readable medium for programming a control computer to generate on demand a gray scale transfer (GST) curve for use in deriving a Look-Up-Table (LUT) for displaying an image comprised of a plurality of digital values representing pixel densities with a desired contrast and brightness, using a single sigmoid function Y=f(X, a, b, c) wherein Y represents output values used in displaying an image, X represents input digital values representing captured image information, b=inv 1n (X max contrast *c) and is a first parameter controlling the location of the curve along the X axis, “c” is between 0.01% to 0.2% of X max value and is a second parameter controlling the curve slope and a=Y u *(1+b*e −cXu ) and wherein X u and Y u represent input and output digital data boundary conditions.
Claim 10
Dependent Claim
144 words
A program embodied in a machine readable medium for programming a control computer to generate on demand a gray scale transfer (GST) curve for use in deriving a Look-Up-Table (LUT) for displaying an image comprised of a plurality of digital values representing pixel densities with a desired contrast and brightness, using a single sigmoid function Y=f(X, a, b, c) wherein Y represents output values used in displaying an image, X represents input digital values representing captured image information, “b” is a first parameter controlling the location of the curve along the X axis, “c” is a second parameter controlling the curve slope and “a” is a number representing boundary conditions, wherein the function Y=f(X, a, b, c) is: Y=a/(1+b*e −cX ) where b=inv 1n (X max contrast *c); “c” is between 0.01% to 0.2% of X max value and: a=Y u *(1+b*e −cXu ).
Claim 11
Dependent Claim
144 words
A program embodied in a machine readable medium for programming a control computer to generate on demand a gray scale transfer (GST) curve for use in deriving a Look-Up-Table (LUT) for displaying an image comprised of a plurality of digital values representing pixel densities with a desired contrast and brightness, using a single sigmoid function Y=f(X, a, b, c) wherein Y represents output values used in displaying an image, X represents input digital values representing captured image information, “b” is a first parameter controlling the location of the curve along the X axis, “c” is a second parameter controlling the curve slope and “a” is a number representing boundary conditions, wherein the function Y=f(X, a, b, c) is: Y=a/(1+b*e −cX ) where b=inv 1n (X max contrast *c); “c” is between 0.01% to 0.2% of X max value and: a=Y u *(1+b*e −cXu ).
Claim 12
Dependent Claim
18 words
The computer program according to claim 7 wherein the output values are digital output values representing a radiogram.
Claim 13
Independent Claim
146 words
A method for displaying an image comprised of a plurality of digital values representing pixel densities with a desired contrast and brightness, the method comprising: deriving a Look-Up-Table (LUT) by generating on demand a gray scale transfer (GST) curve using a single sigmoid function Y=a/(1+b*e −cX ), wherein Y represents output values used in displaying said image, X represents input digital values representing captured image information and wherein: b=inv 1n (X max contrast *c) and is a first parameter controlling the location of the curve along the X axis, “c” is between 0.01% to 0.2% of X max value and is a second parameter controlling the curve slope and a=Y u *(1+b*e −cXu ) wherein X u and Y u represent input and output digital data boundary conditions; and using the derived LUT to modify said plurality of input digital values prior to displaying said image.
Claim 14
Independent Claim
146 words
A method for displaying an image comprised of a plurality of digital values representing pixel densities with a desired contrast and brightness, the method comprising: deriving a Look-Up-Table (LUT) by generating on demand a gray scale transfer (GST) curve using a single sigmoid function Y=a/(1+b*e −cX ), wherein Y represents output values used in displaying said image, X represents input digital values representing captured image information and wherein: b=inv 1n (X max contrast *c) and is a first parameter controlling the location of the curve along the X axis, “c” is between 0.01% to 0.2% of X max value and is a second parameter controlling the curve slope and a=Y u *(1+b*e −cXu ) wherein X u and Y u represent input and output digital data boundary conditions; and using the derived LUT to modify said plurality of input digital values prior to displaying said image.
Claim 15
Dependent Claim
196 words
A program embodied in a machine readable medium for programming a control computer to generate on demand a gray scale transfer (GST) curve for use in deriving a Look-Up-Table (LUT) for modifying a plurality of digital image values representing pixel densities with a first contrast and brightness to modified digital values having desired contrast and brightness, wherein said Look-Up-Table (LUT) is derived by generating on demand a gray scale transfer (GST) curve using a single sigmoid function Y=a/(1+b*e −cX ), and wherein Y represents output values used in displaying said image, X represents input digital values representing captured image information, b=inv 1n (X max contrast *c) and is a first parameter controlling the location of the curve along the X axis, “c” is between 0.01% to 0.2% of X max value and is a second parameter controlling the curve slope, and a=Y u *(1+b*e −cXu ) wherein X u and Y u represent input and output digital image data boundary conditions; and wherein the program further comprises modifying said plurality of input digital image values using said derived LUT and using said modified digital image values to display an image having a desired contrast and brightness.
Claim 16
Dependent Claim
196 words
A program embodied in a machine readable medium for programming a control computer to generate on demand a gray scale transfer (GST) curve for use in deriving a Look-Up-Table (LUT) for modifying a plurality of digital image values representing pixel densities with a first contrast and brightness to modified digital values having desired contrast and brightness, wherein said Look-Up-Table (LUT) is derived by generating on demand a gray scale transfer (GST) curve using a single sigmoid function Y=a/(1+b*e −cX ), and wherein Y represents output values used in displaying said image, X represents input digital values representing captured image information, b=inv 1n (X max contrast *c) and is a first parameter controlling the location of the curve along the X axis, “c” is between 0.01% to 0.2% of X max value and is a second parameter controlling the curve slope, and a=Y u *(1+b*e −cXu ) wherein X u and Y u represent input and output digital image data boundary conditions; and wherein the program further comprises modifying said plurality of input digital image values using said derived LUT and using said modified digital image values to display an image having a desired contrast and brightness.
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| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
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| 3.5 Years (Year 4) | 2005-04-08 | 2005-10-08 | 2006-04-09 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2009-04-08 | 2009-10-08 | 2010-04-09 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2013-04-08 | 2013-10-08 | 2014-04-09 | $7700.00 | Window Closed / Lapsed |