Bilateral filter can be used to smooth the texture while preserving significant edges / contrast.
Below shows a live demo in ShaderToy. Press mouse for comparison.
Thanks to mrharicot’s awesome bilateral filter: https://www.shadertoy.com/view/4dfGDH
With performance improvement proposed by athlete.
With gamma correction by iq: https://www.shadertoy.com/view/XtsSzH
Skin detection forked from carlolsson’s Skin Detection https://www.shadertoy.com/view/MlfSzn#
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// Bilateral Filter for Younger. starea. // URL: https://www.shadertoy.com/view/XtVGWG // Press mouse for comparison. // Filter forked from mrharicot: https://www.shadertoy.com/view/4dfGDH // Skin detection forked from carlolsson's Skin Detection https://www.shadertoy.com/view/MlfSzn# // With performance improvement by athlete #define SIGMA 10.0 #define BSIGMA 0.1 #define MSIZE 15 #define USE_CONSTANT_KERNEL #define SKIN_DETECTION const bool GAMMA_CORRECTION = true; float kernel[MSIZE]; float normpdf(in float x, in float sigma) { return 0.39894 * exp(-0.5 * x * x/ (sigma * sigma)) / sigma; } float normpdf3(in vec3 v, in float sigma) { return 0.39894 * exp(-0.5 * dot(v,v) / (sigma * sigma)) / sigma; } float normalizeColorChannel(in float value, in float min, in float max) { return (value - min)/(max-min); } void mainImage( out vec4 fragColor, in vec2 fragCoord ) { vec3 c = texture2D(iChannel0, (fragCoord.xy / iResolution.xy)).rgb; const int kSize = (MSIZE - 1) / 2; vec3 final_colour = vec3(0.0); float Z = 0.0; #ifdef USE_CONSTANT_KERNEL // unfortunately, WebGL 1.0 does not support constant arrays... kernel[0] = kernel[14] = 0.031225216; kernel[1] = kernel[13] = 0.033322271; kernel[2] = kernel[12] = 0.035206333; kernel[3] = kernel[11] = 0.036826804; kernel[4] = kernel[10] = 0.038138565; kernel[5] = kernel[9] = 0.039104044; kernel[6] = kernel[8] = 0.039695028; kernel[7] = 0.039894000; float bZ = 0.2506642602897679; #else //create the 1-D kernel for (int j = 0; j <= kSize; ++j) { kernel[kSize+j] = kernel[kSize-j] = normpdf(float(j), SIGMA); } float bZ = 1.0 / normpdf(0.0, BSIGMA); #endif vec3 cc; float factor; //read out the texels for (int i=-kSize; i <= kSize; ++i) { for (int j=-kSize; j <= kSize; ++j) { cc = texture2D(iChannel0, (fragCoord.xy+vec2(float(i),float(j))) / iResolution.xy).rgb; factor = normpdf3(cc-c, BSIGMA) * bZ * kernel[kSize+j] * kernel[kSize+i]; Z += factor; if (GAMMA_CORRECTION) { final_colour += factor * pow(cc, vec3(2.2)); } else { final_colour += factor * cc; } } } if (GAMMA_CORRECTION) { fragColor = vec4(pow(final_colour / Z, vec3(1.0/2.2)), 1.0); } else { fragColor = vec4(final_colour / Z, 1.0); } bool isSkin = true; #ifdef SKIN_DETECTION isSkin = false; vec4 rgb = fragColor * 255.0; vec4 ycbcr = rgb; ycbcr.x = 16.0 + rgb.x*0.257 + rgb.y*0.504 + rgb.z*0.098; ycbcr.y = 128.0 - rgb.x*0.148 - rgb.y*0.291 + rgb.z*0.439; ycbcr.z = 128.0 + rgb.x*0.439 - rgb.y*0.368 - rgb.z*0.071; if (ycbcr.y > 100.0 && ycbcr.y < 118.0 && ycbcr.z > 121.0 && ycbcr.z < 161.0) { isSkin = true; } #endif if (iMouse.z > 0.0 || !isSkin) { fragColor = vec4(texture2D(iChannel0, fragCoord.xy / iResolution.xy).xyz, 1.0); } } |
