README.md
In jlmelville/coil20: Code to Download the COIL 20 Database of Object Images

coil20

coil20 is an R package to download the processed images from the COIL-20 database, and COIL-100 database using the R png package.

December 7th 2018 This package has now gained the ability to download the COIL-100 database. Plus, it's better about where it extracts the zip file and cleaning up after itself.

1440 128 x 128 grayscale images (20 objects with 72 poses each), with 16,384 features (the value of the 128 x 128 pixels). The pixel values (reals in the range 0-1) are in columns with name x1_y1, x1_y2, x1_y3 etc. The label representing the object is in the Label column (which is stored as a factor) and the row names store the object id (an integer between 1 and 20) and the pose id (an integer between 0 and 71) which represents the viewing angle of the object.

100 128 x 128 color images (100 objects with 72 poses each) and 49,152 features (the value of the 128 x 128 pixels in the red, green and blue channels). The pixel values (reals in the range 0-1) are in columns with name r_x1_y1, r_x1_y2, r_x1_y3 etc. for the red channel, g_x1_y1 and so on for the green channel, and b_x1_y1 for the blue channel. The label representing the object is in the Label column (which is stored as a factor) and the row names store the object id and the view angle in degrees (an integer between 0 and 355 in increments of 5). This is slightly different to the naming scheme for COIL-20, but follows the nomenclature of the COIL-20 and COIL-100 filenames.

# install.packages("devtools")
devtools::install_github("jlmelville/coil20")
library(coil20)

# fetch the data set from the COIL-20 website
# takes a little while so you might want some indication of what's going on
coil20 <- download_coil20(verbose = TRUE)

# view the zeroth pose of the fourth object
show_object(coil20, object = 4, pose = 0)

# Example of use: PCA
pca <- prcomp(coil20[, 1:128 ^ 2], retx = TRUE)
# plot the scores of the first two components
plot(pca$x[, 1:2], type = 'n')
text(pca$x[, 1:2], labels = coil20$Label, cex = 0.5,
  col = rainbow(length(levels(coil20$Label)))[coil20$Label])

# save data set to disk
save(coil20, file = "coil20.Rda")

# Fetch COIL-100
# Takes a long time to process all 7,200 images (a couple of hours)
coil100 <- download_coil100(verbose = TRUE)