GPU Pro 4

218 III Image Space

//Return the missing chrominance (Co or Cg) of a pixel :

//a1-a4 are the four neighbors of the center pixel a0 .

float filter( vec2 a0 , vec2 a1, vec2 a2 , vec2 a3, vec2 a4)

{

vec4 lum = vec4( a1.x, a2.x , a3.x, a4.x);

vec4 w = 1.0 - step( THRESH, abs(lum - a0.x ));

float W = w.x + w.y + w.z + w.w;

//Handle the special case where all the weights are zero.

W = (W ==0.0)? W : 1.0/ W;

return (w.x*a1.y+w.y*a2.y+w.z*a3.y+w.w*a4.y)*W;

}

Listing 4.2. GLSL implementation of the edge-directed reconstruction filter.

ages, since the luminance is always correct, but they can become more pronounced

when motion is involved.

To eliminate these reconstruction ...