SIGN IN

True color pansharpening can be implemented in Custom script in the following way:

weight = (B04 + B03 + B02 * 0.4) / 2.4;
if (weight == 0) {
  return [0, 0, 0];
}
ratio = B08/weight * 2.5;
return [B04*ratio, B03*ratio, B02*ratio];

If one wants to pansharpen just RED band, it goes along the similar way:

weight = (B04 + B03 + B02 * 0.4) / 2.4;
if (weight == 0) {
  return [0, 0, 0];
}
ratio = B08/weight * 2.5;
return [B04*ratio];