SVD and Image Compression(by Shiny! Yes!) http://blog.supstat.com/2014/03/svd-and-image-compression/

ImgSVD.r

library(rARPACK);
library(jpeg);

factorize = function(m, k){
  r = svds(m[, , 1], k);
  g = svds(m[, , 2], k);
  b = svds(m[, , 3], k);
  return(list(r = r, g = g, b = b));
}

recoverimg = function(lst, k){
  recover0 = function(fac, k){
    dmat = diag(k);
    diag(dmat) = fac$d[1:k];
    m = fac$u[, 1:k] %*% dmat %*% t(fac$v[, 1:k]);
    m[m < 0] = 0;
    m[m > 1] = 1;
    return(m);
  }

  r = recover0(lst$r, k);
  g = recover0(lst$g, k);
  b = recover0(lst$b, k);
  m = array(0, c(nrow(r), ncol(r), 3));
  m[, , 1] = r;
  m[, , 2] = g;
  m[, , 3] = b;
  return(m);
}

rawimg = readJPEG("pic2.jpg");
lst = factorize(rawimg, 100);
neig = c(1, 5, 20, 50, 100);
for(i in neig){
  m = recoverimg(lst, i);
  writeJPEG(m, sprintf("svd_%d.jpg", i), 0.95);
}