#Generate k random matrix points from image matrix
#The input object IMAGE is assumed to be your intensity matrix
#The output is a k x 2 matrix of coordinates for each of k coordinates

GENERATE <- function(IMAGE, k) { n <- nrow(IMAGE);
                                 m <- ncol(IMAGE);
                                 OUTPUT <- data.frame(Row = rep(0,k),
                                                      Column = rep(0,k));
                                 RAND <- sample(1:(n*m), size = k, replace = TRUE,
                                                prob = as.vector(IMAGE))
                                 OUTPUT$Row    <- 1 + RAND %/% n;
                                 OUTPUT$Column <- RAND %% n;
                                 OUTPUT }