If I add the colors of all surrounding texels using a 3x3 kernel, then write the average, shouldnt the entire image move torwards an average color over many iterations of such a filter?
Heres my 3x3 averaging filter:
float4 Average( float2 UV : TEXCOORD0 ) : COLOR0{ float TexelSize = 1.0f / imageWidth; float3 color = 0.0f; color += tex2D( sourceRT, UV + float2( 0.0f, 0.0f )); // get the color of the texel color += tex2D( sourceRT, UV + float2( -TexelSize, 0.0f )); // add the color of the texel to left color += tex2D( sourceRT, UV + float2( TexelSize, 0.0f )); // add the color of the texel to right color += tex2D( sourceRT, UV + float2( 0.0f, -TexelSize )); // add the color of the texel below color += tex2D( sourceRT, UV + float2( 0.0f, TexelSize )); // add the color of the texel above color += tex2D( sourceRT, UV + float2( -TexelSize, -TexelSize )); // add the color of the texel lower left color += tex2D( sourceRT, UV + float2( TexelSize, -TexelSize )); // add the color of the texel lower right color += tex2D( sourceRT, UV + float2( -TexelSize, TexelSize )); // add the color of the texel upper left color += tex2D( sourceRT, UV + float2( TexelSize, TexelSize )); // add the color of the texel upper right float3 average = color / 9.0f; // divide by 9 to get the average of the 9 samples return float4(average, 1.0f); }
On the left is unprocessed. On the right with 10 iterations of the filter.
I would think this would produce an image containing colors moving toward the average of all the colors in the original after a few iterations. But after 10, I only get a very slight blur.
What gives?
[Edited by - josiah7 on June 25, 2008 7:46:58 PM]
