image augmentations of a matrix, data frame, array or a list of 3-dimensional arrays

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Description

image augmentations of a matrix, data frame, array or a list of 3-dimensional arrays

Usage

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Augmentation(image, flip_mode = NULL, crop_width = NULL,
  crop_height = NULL, resiz_width = 0, resiz_height = 0,
  resiz_method = "nearest", shift_rows = 0, shift_cols = 0,
  rotate_angle = 0, rotate_method = "nearest", zca_comps = 0,
  zca_epsilon = 0, image_thresh = 0, threads = 1, verbose = FALSE)

Arguments

image

a matrix, data frame, array or list of 3-dimensional arrays

flip_mode

a character string ('horizontal', 'vertical')

crop_width

an integer specifying the new width of the image, after the image is cropped. Corresponds to the image-rows.

crop_height

an integer specifying the new height of the image, after the image is cropped. Corresponds to the image-columns.

resiz_width

an integer specifying the new width of the image, after the image is resized. Corresponds to the image-rows.

resiz_height

an integer specifying the new height of the image, after the image is resized. Corresponds to the image-columns.

resiz_method

a string specifying the interpolation method when resizing an image ('nearest', 'bilinear')

shift_rows

a positive or negative integer specifying the direction that the rows should be shifted

shift_cols

a positive or negative integer specifying the direction that the columns should be shifted

rotate_angle

an integer specifying the rotation angle of the image

rotate_method

a string specifying the interpolation method when rotating an image ('nearest', 'bilinear')

zca_comps

an integer specifying the number of components to keep by zca whitening, when svd is performed

zca_epsilon

a float specifying the regularization parameter by zca whitening

image_thresh

the threshold parameter, by image thresholding, should be between 0 and 1 if the data is normalized or between 0-255 otherwise

threads

an integer specifying the number of cores to run in parallel ( applies only in case that the image parameter is an array )

verbose

a boolean (TRUE, FALSE). If TRUE, then the total time of the preprocessing task will be printed.

Details

This function takes advantage of various methods to accomplish image augmentations. The order of the preprocessing steps, in case that all transformations are applied to an image, is : 1st flip image, 2nd crop image, 3rd resize image, 4th shift rows or columns, 5th rotate image, 6th zca-whitening and 7th image-thresholding.

Value

the output is of the same type with the input (in case of a data frame it returns a matrix)

Author(s)

Lampros Mouselimis

Examples

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# a matrix
object = matrix(1, 10, 10)

res = Augmentation(object, resiz_width = 8, resiz_height = 8, rotate_angle = 40)


# an array
object = array(0, dim = c(10, 10, 3))

res = Augmentation(object, resiz_width = 8, resiz_height = 8, rotate_angle = 30)


# an array (multiple matrices)
object = array(0, dim = c(10, 10, 10))

res = Augmentation(object, resiz_width = 8, resiz_height = 8, rotate_angle = 20)


# a list of 3-dimensional arrays
object = list(array(0, dim = c(10, 10, 3)), array(0, dim = c(10, 10, 3)))                

res = Augmentation(object, resiz_width = 8, resiz_height = 8, rotate_angle = 40)

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