rotate.matrix: Image Rotation by Bilinear Interpolation

In wvtool: Image Tools for Automated Wood Identification

Description

Three methods to execute rotation by 1) assuming values to destination, 2) obtaining values from the source image by inverse rotation with "nearest neighbor (NN)", 3) previous procedure together with "bilinear interpolation". The default is a rotation with "bilinear Interpolation".

Usage

 
rotate.matrix(x, angle, method="bilinear")

Arguments

x	A raster image or a matrix
angle	Plus(>0) value to request clockwise rotation, while minus for anticlockwise rotation.
method	"simple" assumes values to destination', "NN" obtains values from the source image by inverse rotation with "nearest neighbor", and "bilinear" performs the same but with "bilinear interpolation" of the source image. value to request clockwise rotation.

Details

Assuming 8-bit grayscale image as an input.

Value

A matrix after rotation

See Also

rgb2gray

Examples

data(camphora)
par(mfrow=c(2,2))
r1 <- rotate.matrix(camphora,15, method="simple")
image(rot90c(r1),asp=1,col=grey(c(0:255)/255), main= "simple", 
useRaster=TRUE, axes=FALSE)
r2 <- rotate.matrix(camphora,25, method="NN")
image(rot90c(r2),asp=1,col=grey(c(0:255)/255), main="nearest neighbour", useRaster=TRUE, axes=FALSE)
r3 <- rotate.matrix(camphora,35, method="bilinear")
image(rot90c(r3),asp=1,col=grey(c(0:255)/255),main="bilinear interpolation", 
useRaster=TRUE, axes=FALSE)

Example output

wvtool documentation built on May 1, 2019, 10:27 p.m.