spc4sts (version 0.6.3)

sarGen: Stochastic Autoregressive Image Generator

Description

Generates a 2D stochastic AR(1) image.

Usage

sarGen(phi1 = .6, phi2 = .35, sigma = .01, m = 250, n = 250, border = 200)

Value

The generated image in the matrix format.

Arguments

phi1

the parameter phi1 of the process.

phi2

the parameter phi2 of the process.

sigma

the parameter sigma of the process.

m

the number of rows of the generated image.

n

the number of columns of the generated image.

border

the number of top rows/left columns to be cut off from the generated image. This helps reduce the effect of the starting condition.

Author

Anh Bui

Details

The pixel y(i,j) of the 2D AR(1) process satisfies: y(i,j) = phi1*y(i-1,j) + phi2*y(i,j-1) + e(i,j), where e(i,j) follows a zero-mean Gaussian distribution with standard deviation of sigma. The process is then rescaled to [0, 255] to produce a greyscale image.

References

Bui, A.T. and Apley., D.W. (2018a) "A Monitoring and Diagnostic Approach for Stochastic Textured Surfaces", Technometrics, 60, 1-13.

See Also

imposeDefect

Examples

## generate an image without defects
img <- sarGen(m = 100, n = 100, border = 50)
image(img,col=gray(c(0:32)/32))