Histogramme d'une image

hist_img <- function(img){

  red <- as.vector(img[,,1])*255

 green <- as.vector(img[,,2])*255

 blue <- as.vector(img[,,3])*255

 densite_red <- density(red)

 densite_green <- density(green)

 densite_blue <- density(blue)

 y_max <- max(c(densite_red$y,densite_blue$y,densite_green$y))

plot(red,type="n",xlim=c(0,255),ylim=c(0,y_max),ylab="Fréquence",xlab="Intensité",main=names(img))

 lines(densite_red, col = "red",lwd=3) # Superposer la ligne rouge

 lines(densite_green, col = "green",lwd=3) # Superposer la ligne verte

 lines(densite_blue, col = "blue",lwd=3) # Superposer la ligne bleue

 grid() }

library("png") ; img1<-readPNG("png.png")

hist_img(img1)