Back to results
US 2003/0118246 A1Published application
Biased curve indicator random field filters for enhancement of contours in images
OwnerJonas Augustinventor
Life of this patent
Estimating the term…
Abstract
Enhancement of contours in images that are noisy or otherwise corrupted is important in medical imaging, scanning for weapons detection, and many other fields. Here, the Curve Indicator Random Field (CIRF) is used as a model of uncorrupted images of contours for constructing filters with biased CIRF posterior mean approximations involving a coupled nonlinear system of equations with a number of adjustable parameters.
Claims23
A method of enhancing contours in a noisy image, said method comprising the steps of:
- a) capturing said noisy image as a first distribution m of spatially distributed intensity values
- b) transforming said intensity values of said first distribution m into a second distribution U of spatially distributed intensity values representing an enhanced image having enhanced contours therein, by using a transformation model that is defined by:
- U=U(r)={tilde over (N)}fb={tilde over (N)}f(r)b(r)
- and a pair of equations:
- Qf+c·f+v=0 Q*b+c·b+μ=0
- where:
- U=U(r) comprises an estimate of the probability that a contour passes through location r;
- Ñ is a parameter defining an expected number of contours associated with said noisy image;
- μ comprises an expected distribution of starting points for said contours;
- v comprises an expected distribution of end points for said contours;
- the operation “·” indicates the taking of a componentwise product of two functions, wherein s·v evaluated at location r is the product of the two values s(r) and v(r), where s and v are each functions of r;
- c=c(r) comprises a function of said first distribution m of intensity values;
- f=f(r) comprises an estimate of the probability that a contour continues from location r in a forward direction along a contour;
- b=b(r) comprises an estimate of the probability that a contour continues from location r in a backward direction along a contour;
- Q equals −G−1, the negative of the inverse of the linear operator G=G(r1,r2), where G comprises a matrix of probabilities, each entry of said matrix representing the probability that a contour passing through location r1 passes through location r2 in said forward direction;
- and
- Q* equals −(G*)−1, the negative of the inverse of the linear operator G*=G*(r1,r2), where G* comprises a matrix of probabilities, each entry of said matrix representing the probability that a contour passing through location r1 passes through location r2 in said backward direction.
14 more elements
A computer readable medium including computer instructions for carrying out a method of enhancing contours in a noisy image, said method comprising the steps of:
- a) capturing said noisy image as a first distribution m of spatially distributed intensity values
- b) transforming said intensity values of said first distribution m into a second distribution U of spatially distributed intensity values representing an enhanced image having enhanced contours therein, by using a transformation model that is defined by:
- U=U(r)=Ñfb=Ñf(r)b(r)
- and a pair of equations:
- Qf+c·f+v=0 Q*b+c·b+μ=0
- where:
- U=U(r) comprises an estimate of the probability that a contour passes through location r;
- Ñ is a parameter defining an expected number of contours associated with said noisy image;
- μ comprises an expected distribution of starting points for said contours;
- v comprises an expected distribution of end points for said contours;
- the operation “·” indicates the taking of a componentwise product of two functions, wherein s·v evaluated at location r is the product of the two values s(r) and v(r), where s and v are each functions of r;
- c=c(r) comprises a function of said first distribution m of intensity values;
- f=f(r) comprises an estimate of the probability that a contour continues from location r in a forward direction along a contour;
- b=b(r) comprises an estimate of the probability that a contour continues from location r in a backward direction along a contour;
- Q equals −G−1, the negative of the inverse of the linear operator G=G(r1,r2), where G comprises, a matrix of probabilities, each entry of said matrix representing the probability that a contour passing through location r1 passes through location r2 in said forward direction;
- and
- Q* equals −(G*)−1, the negative of the inverse of the linear operator G*=G*(r1,r2), where G* comprises a matrix of probabilities, each entry of said matrix representing the probability that a contour passing through location r1 passes through location r2 in said backward direction.
14 more elements
A system for enhancing contours in a noisy image, said system comprising:
- a) a camera for capturing said noisy image as a first distribution m of spatially distributed intensity values
- b) a computer for transforming said intensity values of said first distribution m into a second distribution U of spatially distributed intensity values representing an enhanced image having enhanced contours therein, by using a transformation model that is defined by:
- U=U(r)=Ñfb=Ñf(r)b(r)
- and a pair of equations:
- Qf+c·f+v=0 Q*b+c·b+μ=0
- where:
- U=U(r) comprises an estimate of the probability that a contour passes through location r;
- Ñ is a parameter defining an expected number of contours associated with said noisy image;
- μ comprises an expected distribution of starting points for said contours;
- v comprises an expected distribution of end points for said contours;
- the operation “·” indicates the taking of a componentwise product of two functions, wherein s·v evaluated at location r is the product of the two values s(r) and v(r), where s and v are each functions of r;
- c=c(r) comprises a function of said first distribution m of intensity values;
- f=f(r) comprises an estimate of the probability that a contour continues from location r in a forward direction along a contour;
- b=b(r) comprises an estimate of the probability that a contour continues from location r in a backward direction along a contour;
- Q equals −G−1, the negative of the inverse of the linear operator G=G(r1,r2), where G comprises a matrix of probabilities, each entry of said matrix representing the probability that a contour passing through location r1 passes through location r2 in said forward direction;
- and
- Q* equals −(G*)−1, the negative of the inverse of the linear operator G*=G*(r1,r2), where G* comprises a matrix of probabilities, each entry of said matrix representing the probability that a contour passing through location r1 passes through location r2 in said backward direction.
14 more elements
Dependencies are inferred from the claim text.