src/test/scripts/functions/parfor/parfor_image_brightness.R

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args = commandArgs(TRUE)
options(digits=22)
library("Matrix")

adjustBrightness = function(M, val, chan_max) {
  out = pmax(0, pmin(M + val, chan_max))
  out = matrix(out, nrow(M), ncol(M), byrow=FALSE)
  return(out)
}

images = as.matrix(readMM(paste(args[1], "A.mtx", sep="")))
width = as.integer(args[3])
height = as.integer(args[4])
brightness_adjustments = as.matrix(readMM(paste(args[1], "brightness_adjustments.mtx", sep="")))
num_augmentations = nrow(brightness_adjustments)
augmented_images = matrix(0, num_augmentations * nrow(images), ncol(images))
max_value=255

for (idx in 0:(nrow(images)-1)) {
  i = idx + 1

  image2d = matrix(images[i,], width, height, byrow=TRUE)

  for(a in 1:num_augmentations) {
    # do augmentation
    img_out = adjustBrightness(image2d, as.integer(brightness_adjustments[a,1]), max_value)
    
    # reshape and store augmentation
    augmented_images[idx*num_augmentations+a,] = matrix(t(img_out), 1, width * height, byrow=TRUE)
  }
}

writeMM(as(augmented_images, "CsparseMatrix"), paste(args[2], "B", sep=""))