Image Manipulation of the Lloyd's Building

kmeans_palette.R

library("ReadImages")

url <-"http://upload.wikimedia.org/wikipedia/commons/6/6a/6414A_1_copy.jpg"

download.file(url, "tempPicture.jpg", mode = "wb")  # Stash image locally
readImage <- read.jpeg("tempPicture.jpg")

dm <- dim(readImage)
rgbImage <- data.frame(
                    x=rep(1:dm[2], each=dm[1]),
                    y=rep(dm[1]:1, dm[2]),
                    r.value=as.vector(readImage[,,1]),
                    g.value=as.vector(readImage[,,2]),
                    b.value=as.vector(readImage[,,3]))

with(rgbImage, 
     plot(x, y, 
          col = rgb(rgbImage[c("r.value", "g.value", "b.value")]), 
          asp = 1, pch = "."))


# Cluster in color space:
kColors <- 5  # Number of palette colors
kMeans <- kmeans(rgbImage[, c("r.value", "g.value", "b.value")], centers = kColors)

plot(factor(kMeans$cluster), col=rgb(kMeans$centers),
     xlab="Cluster", ylab="Count")

approximateColor <- kMeans$centers[kMeans$cluster, ]

pdf("~/Desktop/LloydsBuilding.pdf")
with(rgbImage, plot(x, y, col = rgb(approximateColor), asp = 1, pch = ".",
                    axes=FALSE, ylab="", xlab="Lloyd's building"))
dev.off()

## Using data.table

pkgs <- c("ReadImages", "data.table")
lapply(pkgs, library, character.only = TRUE)

url <-"http://upload.wikimedia.org/wikipedia/commons/6/6a/6414A_1_copy.jpg"

download.file(url, "tempPicture.jpg", mode = "wb")  # Stash image locally
readImage <- read.jpeg("tempPicture.jpg")

dm <- dim(readImage)
rgbImage <- data.table(
                    x=rep(1:dm[2], each=dm[1]),
                    y=rep(dm[1]:1, dm[2]),
                    r.value=as.vector(readImage[,,1]),
                    g.value=as.vector(readImage[,,2]),
                    b.value=as.vector(readImage[,,3]))

with(rgbImage, 
     plot(x, y, 
          col = rgb(rgbImage[, list(r.value, g.value, b.value)]), 
          asp = 1, pch = "."))


# Cluster in color space:
kColors <- 5  # Number of palette colors
kMeans <- kmeans(rgbImage[, list(r.value, g.value, b.value)], centers = kColors)

plot(factor(kMeans$cluster), col=rgb(kMeans$centers),
     xlab="Cluster", ylab="Count")

approximateColor <- kMeans$centers[kMeans$cluster, ]

pdf("~/Desktop/LloydsBuilding.pdf")
with(rgbImage, plot(x, y, col = rgb(approximateColor), asp = 1, pch = ".",
                    axes=FALSE, ylab="", xlab="Lloyd's building"))
dev.off()