@luma.gl/effects/src/shader-modules/adjust-filters/denoise.js

Rendering and post-processing effects library for luma.gl

/**
 * @filter         Denoise
 * @description    Smooths over grainy noise in dark images using an 9x9 box filter
 *                 weighted by color intensity, similar to a bilateral filter.
 * @param exponent The exponent of the color intensity difference, should be greater
 *                 than zero. A value of zero just gives an 9x9 box blur and high values
 *                 give the original image, but ideal values are usually around 10-20.
 */

// Do a 9x9 bilateral box filter
const fs = `\
uniform float strength;

vec4 denoise_sampleColor(sampler2D texture, vec2 texSize, vec2 texCoord) {
  float adjustedExponent = 3. + 200. * pow(1. - strength, 4.);

  vec4 center = texture2D(texture, texCoord);
  vec4 color = vec4(0.0);
  float total = 0.0;
  for (float x = -4.0; x <= 4.0; x += 1.0) {
    for (float y = -4.0; y <= 4.0; y += 1.0) {
      vec4 sample = texture2D(texture, texCoord + vec2(x, y) / texSize);
      float weight = 1.0 - abs(dot(sample.rgb - center.rgb, vec3(0.25)));
      weight = pow(weight, adjustedExponent);
      color += sample * weight;
      total += weight;
    }
  }

  return color / total;
}
`;

const uniforms = {
  strength: {
    value: 0.5,
    min: 0,
    max: 0.1,
    adjust: strength => 0.53 + 200 * Math.pow(1 - strength, 4) // TODO - JS preprocessing
  }
};

export default {
  name: 'denoise',
  uniforms,
  fs,

  passes: [{sampler: true}, {sampler: true}]
};