# Converting pictures into numerical values

I am working to make my first trained model for image recognition, using the programming language R.

First I am attempting to make a function that takes a PNG-image as input, resizes it to 128x128 pixels, and converts it into a row-vector of numbers representing the colours in each pixel. I then want to add this to a file that contains my training-set and labels (the image bank).

I am having some trouble with this, being a beginner in R, as the numerical values I get out from the following code does not make sense to me - often I get a large amount of 1's, and the pictures appear to be completely white if I try to export and look at the image.

Is there any obvious mistake here? I assume it must be where I convert to numerical values. Alternatively, is there an alternative approach to this task that would be better?

load_png_to_image_bank <- function(wd, input_file, label) {

# Remembers old working directory
oldwd <- wd

# Sets input wd to file location
setwd(wd)

library(imager)

# Imports file and resizes to 128x128 pixels
image <- resize(image,128,128)

# Finds numerical values for each pixel
rasterized_vector <- as.data.frame(as.vector(image))
rasterized_vector <- as.data.frame(t(rasterized_vector))

# Adds label defined by input variable
rasterized_vector <- as.data.frame((cbind(1, rasterized_vector)))
names(rasterized_vector)[1] <- label

# Sets wd to predetermined place for image bank file
setwd(" ... ")

# Writes vector to file
write.table(rasterized_vector,
output_file,
row.names=F,
na="NA",
append = T,
quote= FALSE,
sep = ";",
col.names = F)

# Resets working directory to initial state
setwd(oldwd)

}

• Maybe it's better to submit this kind of questions to programming forums, such as Stack Overflow or R dedicated forum. It's more an R question rather than an AI question. – rursw1 Aug 27 '17 at 8:37