Description Usage Arguments Value References See Also Examples
This function can be used to analyze a continuous image in .png or .jpeg format, or an image represented as a list object in the format of parnormobs.
1 2 |
image |
This may be a string representing the path to a .png or .jpeg file, or a list object in the same format as par2obs output, with intensity, r.obs, theta.obs, and center the required list contents. |
gamma.fun |
This is a function, like triangle2 or ellipse, denoting the true boundary. It is optional and only used when the image input refers to a .png or .jpeg file. |
center |
This is required if the image input refers to a .png or .jpeg file, otherwise it is unused. |
inimean |
a constant to specify the initial mean functions in the Bayesian estimation. |
nrun |
the number of MCMC samples to keep for estimation. |
nburn |
the number of initial MCMC samples to discard. |
J |
truncation number of the Gaussian process kernel. The number of eigenfunctions is 2J + 1. |
ordering_mu |
Indicates which Gaussian distribution has larger mean intensity: "I", the Gaussian distribution inside the boundary; "O", the Gaussian distribution outside the boundary; "N", no ordering information is available. |
ordering_sigma |
Indicates which Gaussian distribution has larger intensity variance: "I", the Gaussian distribution inside the boundary; "O", the Gaussian distribution outside the boundary; "N", no ordering information is available. |
mask |
Logical vector (same length as obs$intensity) to indicate region of interest. Should this data point be included in the analysis? |
slice |
boolean where TRUE means that slice sampling will be used to sample Fourier basis function coefficients and FALSE means that Metropolis-Hastings will be used instead. |
outputAll |
boolean controlling the amount of output produced, see value below. |
output |
If outputAll is FALSE,
estimate |
Posterior mean estimate of image boundary at theta values. |
theta |
A grid of 200 values on [0,2π] at which to retrun the estimated boundary. |
lower, upper |
The lower and upper bounds of a 95\% uniform credible band for the image boundary. |
If outputAll is TRUE, same as above, and additionally,
musig.smp |
posterior samples of μ_1, μ_2, σ_1, and σ_2. |
coef.smp |
posterior samples of Fourier basis function coefficients. |
image |
the input image passed to fitContImage. |
obs |
the processed image data passed to BayesBDnormal. |
Li, M. and Ghosal, S.(2015) "Bayesian Detection of Image Boundaries." arXiv 1508.05847.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 | ## Not run:
set.seed(12345)
gamma.fun = ellipse(a = 0.35, b = 0.25)
norm.obs = parnormobs(m = 100, mu.in = 4, mu.out = 1,
sd.in = 1.5, sd.out = 1, design = 'J',
center = c(0.5,0.5), gamma.fun)
norm.samp = fitContImage(image = norm.obs, nrun = 1000, nburn = 0,
J = 10,ordering_mu = "I",ordering_sigma = "I", slice = FALSE, outputAll = FALSE)
par(mfrow = c(1,3))
plotBD(norm.samp, 1)
plotBD(norm.samp, 2)
plotBD(norm.samp, 3)
## End(Not run)
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