Warp Affine
warpAffine(img, M, R, C, threads = 1, verbose = FALSE)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
a matrix corresponding to the transformation matrix
a value corresponding to the destination number of rows
a value corresponding to the destination number of columns
an integer specifying the number of threads to run in parallel. This parameter applies only if the input "img" parameter is of type matrix.
a boolean. If TRUE then information will be printed in the console
either a matrix or a 3-dimensional array (where the third dimension is equal to 3)
https://github.com/OlehOnyshchak/ImageTransformations/blob/master/AffineTransformation.ipynb
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)
#> time to complete : 0.036 secs
# imageShow(res_2d)
#..............
# 3-dimensional
#..............
res_3d = warpAffine(img = img,
M = M_aff,
R = r,
C = c,
verbose = TRUE)
#> time to complete : 0.1354 secs
# imageShow(res_3d)