void nearestNeighbour(Pixels &pixels, int channel) {
for(int i=1; i<pixels.size(); i++) {
for(int j=1; j<pixels[i].size(); j++) {
if(i%2 == 0) {
if(j%2 == 0) {
if(channel == RED) {
pixels[i][j].setChannelWithPixel(channel, pixels[i-1][j-1]);
} else if(channel == GREEN) {
pixels[i][j].setChannelWithPixel(channel, pixels[i-1][j]);
}
} else {
if(channel == RED) {
pixels[i][j].setChannelWithPixel(channel, pixels[i-1][j]);
} else if(channel == BLUE) {
pixels[i][j].setChannelWithPixel(channel, pixels[i][j-1]);
}
}
} else {
if(j%2 == 0) {
if(channel == RED) {
pixels[i][j].setChannelWithPixel(channel, pixels[i][j-1]);
} else if(channel == BLUE) {
pixels[i][j].setChannelWithPixel(channel, pixels[i-1][j]);
}
} else {
if(channel == BLUE) {
pixels[i][j].setChannelWithPixel(channel, pixels[i-1][j-1]);
} else if(channel == GREEN) {
pixels[i][j].setChannelWithPixel(channel, pixels[i-1][j]);
}
}
}
}
}
}
SplineFunction::SplineFunction(Pixels& pixels, int direction, int i) :
pixels(pixels)
{
// si es vertical, las columnas serian las filas de la imagen
cols = direction == HORIZONTAL ? pixels[0].size() : pixels.size(); // saco los bordes
if(cols % 2 == 0) {
points_count = cols/2;
} else {
points_count = cols/2 - (i+1)%2; // si la fila es par hay un pixel verde menos
}
splines_count = points_count-1;
h = 2;
c_matrix = new vector<vector<double>>(points_count, vector<double>(points_count));
v = new vector<double>(points_count);
a.resize(points_count);
b.resize(points_count);
c.resize(points_count);
d.resize(points_count);
if(direction == HORIZONTAL) DoHorizontal(i);
else DoVertical(i);
delete(c_matrix);
delete(v);
}
void directional_interpolation(Pixels& pixels)
{
int rows = pixels.size();
int cols = pixels[0].size();
vector<SplineFunction*> horizontal_splines(rows);
vector<SplineFunction*> vertical_splines(cols);
horizontal_splines[0] = NULL;
for(int i = 1; i < rows-1; i++)
{
horizontal_splines[i] = new SplineFunction(pixels, HORIZONTAL, i);
}
horizontal_splines[rows-1] = NULL;
vertical_splines[0] = NULL;
for(int i = 1; i < cols-1; i++)
{
vertical_splines[i] = new SplineFunction(pixels, VERTICAL, i);
}
vertical_splines[cols-1] = NULL;
for(int i = 1; i < rows-1; i++)
{
for(int j = 1; j < cols-1; j++)
{
if((i % 2 == 0 && j % 2 == 1) || (i % 2 == 1 && j % 2 == 0)) continue; // avoid green locations
double gradient_v = (i >=2 && i <= rows-3) ? abs(pixels[i+2][j].green - pixels[i-2][j].green) : 0;
double gradient_h = (j >=2 && j <= cols-3) ? abs(pixels[i][j+2].green - pixels[i][j-2].green) : 0;
double value_v = vertical_splines[j]->eval(i);
double value_h = horizontal_splines[i]->eval(j);
double avg;
if(gradient_h == gradient_v)
avg = (value_h + value_v)/2;
else {
avg = value_h * (gradient_v / (gradient_h + gradient_v))
+ value_v * (gradient_h / (gradient_h + gradient_v));
}
pixels[i][j].green = MAX(0, MIN(255, round(avg)));
}
delete horizontal_splines[i];
}
for(int i = 1; i < cols-1; i++)
{
delete vertical_splines[i];
}
}
void bilinear(Pixels &pixels, int channel) {
int color;
for(int i=1; i<pixels.size()-1; i++) {
for(int j=1; j<pixels[i].size()-1; j++) {
if(i%2 == 0) {
if(j%2 == 0) {
if(channel == RED) {
color = (pixels[i-1][j-1].getChannel(channel) + pixels[i-1][j+1].getChannel(channel) +
pixels[i+1][j-1].getChannel(channel) + pixels[i+1][j+1].getChannel(channel)) / 4;
pixels[i][j].setChannelWithColor(channel, color);
} else if(channel == GREEN) {
color = (pixels[i-1][j].getChannel(channel) + pixels[i][j-1].getChannel(channel) +
pixels[i][j+1].getChannel(channel) + pixels[i+1][j].getChannel(channel)) / 4;
pixels[i][j].setChannelWithColor(channel, color);
}
} else {
if(channel == RED) {
color = (pixels[i-1][j].getChannel(channel) + pixels[i+1][j].getChannel(channel)) / 2;
pixels[i][j].setChannelWithColor(channel, color);
} else if(channel == BLUE) {
color = (pixels[i][j-1].getChannel(channel) + pixels[i][j+1].getChannel(channel)) / 2;
pixels[i][j].setChannelWithColor(channel, color);
}
}
} else {
if(j%2 == 0) {
if(channel == RED) {
color = (pixels[i][j-1].getChannel(channel) + pixels[i][j+1].getChannel(channel)) / 2;
pixels[i][j].setChannelWithColor(channel, color);
} else if(channel == BLUE) {
color = (pixels[i-1][j].getChannel(channel) + pixels[i+1][j].getChannel(channel)) / 2;
pixels[i][j].setChannelWithColor(channel, color);
}
} else {
if(channel == BLUE) {
color = (pixels[i-1][j-1].getChannel(channel) + pixels[i-1][j+1].getChannel(channel) +
pixels[i+1][j-1].getChannel(channel) + pixels[i+1][j+1].getChannel(channel)) / 4;
pixels[i][j].setChannelWithColor(channel, color);
} else if(channel == GREEN) {
color = (pixels[i-1][j].getChannel(channel) + pixels[i][j-1].getChannel(channel) +
pixels[i][j+1].getChannel(channel) + pixels[i+1][j].getChannel(channel)) / 4;
pixels[i][j].setChannelWithColor(channel, color);
}
}
}
}
}
}
void MHC(Pixels& pixels) // only supports green channel
{
int color, rhombus_sum;
double gradient;
bilinear(pixels, GREEN); // se arranca con la bilinear
for(int i=2; i<pixels.size()-2; i++) {
for(int j=2; j<pixels[i].size()-2; j++) {
if((i % 2 == 0 && j % 2 == 1) || (i % 2 == 1 && j % 2 == 0)) continue; // green locations
color = i % 2 == 0 ? BLUE : RED;
rhombus_sum = 0;
rhombus_sum += pixels[i][j-2].getChannel(color);
rhombus_sum += pixels[i][j+2].getChannel(color);
rhombus_sum += pixels[i-2][j].getChannel(color);
rhombus_sum += pixels[i+2][j].getChannel(color);
gradient = pixels[i][j].getChannel(color) - rhombus_sum / 4.0;
pixels[i][j].green += int(ALPHA * gradient);
pixels[i][j].green = MAX(0, MIN(255, pixels[i][j].green));
}
}
}
