statistic-on-air

# Sierra 2-4a dithering filter

Sierra24aConvolution <- function(a){

c <- matrix(0, nrow=dim(a)[1], ncol=dim(a)[2])

for(i in 2:(dim(a)[1]-2)){
for(j in 2:(dim(a)[2]-2)){
	P <- trunc(a[i,j]+0.5)
	e <- a[i,j] - P

statistic-on-air

# Jarvis-Judice-Ninke dithering

JJNConvolution <- function(a){

c <- matrix(0, nrow=dim(a)[1], ncol=dim(a)[2])

for(i in 2:(dim(a)[1]-2)){
for(j in 2:(dim(a)[2]-2)){
	P <- trunc(a[i,j]+0.5)
	e <- a[i,j] - P

statistic-on-air

# Bill Atkinson dithering

AtkinConvolution <- function(a){

c <- matrix(0, nrow=dim(a)[1], ncol=dim(a)[2])

for(i in 2:(dim(a)[1]-2)){
for(j in 2:(dim(a)[2]-2)){
	P <- trunc(a[i,j]+0.5)
	e <- a[i,j] - P

statistic-on-air

# Floyd-Steinberg dithering

# the 2-dimensional convolution function
FloydConvolution <- function(a){

c <- matrix(0, nrow=dim(a)[1], ncol=dim(a)[2])

for(i in 1:(dim(a)[1]-1)){
for(j in 1:(dim(a)[2]-1)){
	P <- trunc(a[i,j]+0.5)

statistic-on-air

# Floyd-Steinberg dithering

# the 2-dimensional convolution function
FloydConvolution <- function(a){

c <- matrix(0, nrow=dim(a)[1], ncol=dim(a)[2])

for(i in 1:(dim(a)[1]-1)){
for(j in 1:(dim(a)[2]-1)){
	P <- trunc(a[i,j]+0.5)

statistic-on-air

# the 2-dimensional convolution function
FloydConvolution <- function(a){

c <- matrix(0, nrow=dim(a)[1], ncol=dim(a)[2])

for(i in 1:(dim(a)[1]-1)){
for(j in 1:(dim(a)[2]-1)){
	P <- trunc(a[i,j]+0.5)
	e <- a[i,j] - P
	a[i,j] <- P