warpAffine: Warp Affine

In mlampros/OpenImageR: An Image Processing Toolkit

Warp Affine

Description

Warp Affine

Usage

warpAffine(img, M, R, C, threads = 1, verbose = FALSE)

Arguments

img	either a matrix or a 3-dimensional array (where the third dimension is equal to 3) with a range of values between 0 and 255
M	a matrix corresponding to the transformation matrix
R	a value corresponding to the destination number of rows
C	a value corresponding to the destination number of columns
threads	an integer specifying the number of threads to run in parallel. This parameter applies only if the input "img" parameter is of type matrix.
verbose	a boolean. If TRUE then information will be printed in the console

Value

either a matrix or a 3-dimensional array (where the third dimension is equal to 3)

References

https://github.com/OlehOnyshchak/ImageTransformations/blob/master/AffineTransformation.ipynb

Examples

require(OpenImageR)

path = system.file("tmp_images", "landscape.jpg", package = "OpenImageR")
img = readImage(path)
img = img * 255

#.............................
# compute the affine transform
#.............................

r = ncol(img)
c = nrow(img)
offset = 50

original_points = matrix(data = c(0, 0, r, 0, 0, c),
                         nrow = 3,
                         ncol = 2,
                         byrow = TRUE)

transformed_points = matrix(data = c(offset, 0, r, offset, 0, c-offset),
                            nrow = 3,
                            ncol = 2,
                            byrow = TRUE)

M_aff = getAffineTransform(original_points = original_points,
                           transformed_points = transformed_points)

#..............
# 2-dimensional
#..............

img_2d = rgb_2gray(img)

res_2d = warpAffine(img = img_2d,
                    M = M_aff,
                    R = r,
                    C = c,
                    threads = 1,
                    verbose = TRUE)

# imageShow(res_2d)

#..............
# 3-dimensional
#..............

res_3d = warpAffine(img = img,
                    M = M_aff,
                    R = r,
                    C = c,
                    verbose = TRUE)

# imageShow(res_3d)

mlampros/OpenImageR documentation built on July 30, 2023, 1:17 a.m.