File:Incoherent sum of speckles.webm

Summary

Description
English: Coherent light passing through a scattering medium is scrambled into a speckle pattern. But if there are multiple sources incoherent with each other, the resulting pattern will be the incoherent sum of the speckle patterns generated by each source.
Date
Source https://twitter.com/j_bertolotti/status/1553005005304696832
Author Jacopo Bertolotti
Permission
(Reusing this file)
https://twitter.com/j_bertolotti/status/1030470604418428929

Mathematica 13.0 code

dim = 256;
texture = ExampleData[{"Texture", "Sand3"}];
color1[x_] := RGBColor[0.368417, 0.506779, 0.709798, x];
color2[x_] := RGBColor[0.922526, 0.385626, 0.209179, x];
speckle[] := 
  Abs[Fourier[
    RandomComplex[{-1 - I, 1 + I}, {dim, dim}]*
     GaussianMatrix[{dim/2, dim/30}][[1 ;; -2, 1 ;; -2]]]]^2;
tmp1 = speckle[]*
  GaussianMatrix[{dim/2, dim/4}][[1 ;; -2, 1 ;; -2]]; tmp1 = tmp1/
 Max[tmp1];
tmp2 = speckle[]*
  GaussianMatrix[{dim/2, dim/4}][[1 ;; -2, 1 ;; -2]]; tmp2 = tmp2/
 Max[tmp2];
tmp3 = speckle[]*
  GaussianMatrix[{dim/2, dim/4}][[1 ;; -2, 1 ;; -2]]; tmp3 = tmp3/
 Max[tmp3];
source1 = 
 RotateRight[
  GaussianMatrix[{dim/2, dim/40}][[1 ;; -2, 1 ;; -2]], {-50, 
   20}]; source1 = source1/Max[source1];
source2 = 
 RotateRight[
  GaussianMatrix[{dim/2, dim/40}][[1 ;; -2, 1 ;; -2]], {50, 
   80}]; source2 = source2/Max[source2];
source3 = 
 RotateRight[
  GaussianMatrix[{dim/2, dim/40}][[1 ;; -2, 
   1 ;; -2]], {20, -50}]; source3 = source3/Max[source3];

frames1 = Table[
   s = ArrayPlot[a*tmp1, DataReversed -> True, 
     ColorFunction -> "SunsetColors", ColorFunctionScaling -> False, 
     PlotRangePadding -> None];
   sourceplot = 
    ArrayPlot[a*source1, DataReversed -> True, 
     ColorFunction -> "SunsetColors", ColorFunctionScaling -> False, 
     PlotRangePadding -> None];
   Graphics3D[{
     Texture[texture], 
     Polygon[{{-1.5, 2, -1.5}, {-1.5, 2, 1.5}, {1.5, 2, 1.5}, {1.5, 
        2, -1.5}}, 
      VertexTextureCoordinates -> {{0, 0}, {1, 0}, {1, 1}, {0, 1}}],
     Texture[sourceplot], 
     Polygon[{{-1.5, 5, -1.5}, {-1.5, 5, 1.5}, {1.5, 5, 1.5}, {1.5, 
        5, -1.5}}, 
      VertexTextureCoordinates -> {{0, 0}, {1, 0}, {1, 1}, {0, 1}}]
     , Black, Thick, 
     Line[{{-1.5, 2, -1.5}, {-1.5, 2, 1.5}, {1.5, 2, 1.5}, {1.5, 
        2, -1.5}, {-1.5, 2, -1.5}}], 
     Texture[s], 
     Polygon[{{-1.5, -1, -1.5}, {-1.5, -1, 1.5}, {1.5, -1, 
        1.5}, {1.5, -1, -1.5}}, 
      VertexTextureCoordinates -> {{0, 0}, {1, 0}, {1, 1}, {0, 1}}]
     }, PlotRange -> {{-2, 2}, {-1.5, 5}, {-2, 2}}, 
    ViewPoint -> {-1.3, - 2.4, 2.}, Boxed -> False, 
    Lighting -> "Neutral", Background -> White]
   , {a, 0, 1, 0.1}];

frames2 = Table[
   s = ArrayPlot[a*tmp2, DataReversed -> True, 
     ColorFunction -> "SunsetColors", ColorFunctionScaling -> False, 
     PlotRangePadding -> None];
   sourceplot = 
    ArrayPlot[a*source2, DataReversed -> True, 
     ColorFunction -> "SunsetColors", ColorFunctionScaling -> False, 
     PlotRangePadding -> None];
   Graphics3D[{
     Texture[texture], 
     Polygon[{{-1.5, 2, -1.5}, {-1.5, 2, 1.5}, {1.5, 2, 1.5}, {1.5, 
        2, -1.5}}, 
      VertexTextureCoordinates -> {{0, 0}, {1, 0}, {1, 1}, {0, 1}}],
     Texture[sourceplot], 
     Polygon[{{-1.5, 5, -1.5}, {-1.5, 5, 1.5}, {1.5, 5, 1.5}, {1.5, 
        5, -1.5}}, 
      VertexTextureCoordinates -> {{0, 0}, {1, 0}, {1, 1}, {0, 1}}]
     , Black, Thick, 
     Line[{{-1.5, 2, -1.5}, {-1.5, 2, 1.5}, {1.5, 2, 1.5}, {1.5, 
        2, -1.5}, {-1.5, 2, -1.5}}], 
     Texture[s], 
     Polygon[{{-1.5, -1, -1.5}, {-1.5, -1, 1.5}, {1.5, -1, 
        1.5}, {1.5, -1, -1.5}}, 
      VertexTextureCoordinates -> {{0, 0}, {1, 0}, {1, 1}, {0, 1}}]
     }, PlotRange -> {{-2, 2}, {-1.5, 5}, {-2, 2}}, 
    ViewPoint -> {-1.3, - 2.4, 2.}, Boxed -> False, 
    Lighting -> "Neutral", Background -> White]
   , {a, 0, 1, 0.1}];

frames3 = Table[
   s = ArrayPlot[a*tmp3, DataReversed -> True, 
     ColorFunction -> "SunsetColors", ColorFunctionScaling -> False, 
     PlotRangePadding -> None];
   sourceplot = 
    ArrayPlot[a*source3, DataReversed -> True, 
     ColorFunction -> "SunsetColors", ColorFunctionScaling -> False, 
     PlotRangePadding -> None];
   Graphics3D[{
     Texture[texture], 
     Polygon[{{-1.5, 2, -1.5}, {-1.5, 2, 1.5}, {1.5, 2, 1.5}, {1.5, 
        2, -1.5}}, 
      VertexTextureCoordinates -> {{0, 0}, {1, 0}, {1, 1}, {0, 1}}],
     Texture[sourceplot], 
     Polygon[{{-1.5, 5, -1.5}, {-1.5, 5, 1.5}, {1.5, 5, 1.5}, {1.5, 
        5, -1.5}}, 
      VertexTextureCoordinates -> {{0, 0}, {1, 0}, {1, 1}, {0, 1}}]
     , Black, Thick, 
     Line[{{-1.5, 2, -1.5}, {-1.5, 2, 1.5}, {1.5, 2, 1.5}, {1.5, 
        2, -1.5}, {-1.5, 2, -1.5}}], 
     Texture[s], 
     Polygon[{{-1.5, -1, -1.5}, {-1.5, -1, 1.5}, {1.5, -1, 
        1.5}, {1.5, -1, -1.5}}, 
      VertexTextureCoordinates -> {{0, 0}, {1, 0}, {1, 1}, {0, 1}}]
     }, PlotRange -> {{-2, 2}, {-1.5, 5}, {-2, 2}}, 
    ViewPoint -> {-1.3, - 2.4, 2.}, Boxed -> False, 
    Lighting -> "Neutral", Background -> White]
   , {a, 0, 1, 0.1}];

frames4 = Table[
   s = ArrayPlot[a*(tmp1 + tmp2 + tmp3), DataReversed -> True, 
     ColorFunction -> "SunsetColors", ColorFunctionScaling -> False, 
     PlotRangePadding -> None];
   sourceplot = 
    ArrayPlot[a*(source1 + source2 + source3), DataReversed -> True, 
     ColorFunction -> "SunsetColors", ColorFunctionScaling -> False, 
     PlotRangePadding -> None];
   Graphics3D[{
     Texture[texture], 
     Polygon[{{-1.5, 2, -1.5}, {-1.5, 2, 1.5}, {1.5, 2, 1.5}, {1.5, 
        2, -1.5}}, 
      VertexTextureCoordinates -> {{0, 0}, {1, 0}, {1, 1}, {0, 1}}],
     Texture[sourceplot], 
     Polygon[{{-1.5, 5, -1.5}, {-1.5, 5, 1.5}, {1.5, 5, 1.5}, {1.5, 
        5, -1.5}}, 
      VertexTextureCoordinates -> {{0, 0}, {1, 0}, {1, 1}, {0, 1}}]
     , Black, Thick, 
     Line[{{-1.5, 2, -1.5}, {-1.5, 2, 1.5}, {1.5, 2, 1.5}, {1.5, 
        2, -1.5}, {-1.5, 2, -1.5}}], 
     Texture[s], 
     Polygon[{{-1.5, -1, -1.5}, {-1.5, -1, 1.5}, {1.5, -1, 
        1.5}, {1.5, -1, -1.5}}, 
      VertexTextureCoordinates -> {{0, 0}, {1, 0}, {1, 1}, {0, 1}}]
     }, PlotRange -> {{-2, 2}, {-1.5, 5}, {-2, 2}}, 
    ViewPoint -> {-1.3, - 2.4, 2.}, Boxed -> False, 
    Lighting -> "Neutral", Background -> White]
   , {a, 0, 1, 0.1}];

time1 = Sum[
   UnitStep[t - \[Tau]] E^(-0.5 (t - \[Tau])), {\[Tau], 
    Evaluate[
     Accumulate@RandomVariate[ExponentialDistribution[0.1], {20}]]}];
timeseries1 = Table[time1, {t, 1, 100, 1}];
time2 = Sum[
   UnitStep[t - \[Tau]] E^(-0.5 (t - \[Tau])), {\[Tau], 
    Evaluate[
     Accumulate@RandomVariate[ExponentialDistribution[0.1], {20}]]}];
timeseries2 = Table[time2, {t, 1, 100, 1}];
time3 = Sum[
   UnitStep[t - \[Tau]] E^(-0.5 (t - \[Tau])), {\[Tau], 
    Evaluate[
     Accumulate@RandomVariate[ExponentialDistribution[0.1], {20}]]}];
timeseries3 = Table[time3, {t, 1, 100, 1}];

frames5 = Table[
   s = ArrayPlot[(timeseries1[[t]]*tmp1 + timeseries2[[t]]*tmp2 + 
       timeseries3[[t]]*tmp3), DataReversed -> True, 
     ColorFunction -> "SunsetColors", ColorFunctionScaling -> False, 
     PlotRangePadding -> None];
   sourceplot = 
    ArrayPlot[(timeseries1[[t]]*source1 + timeseries2[[t]]*source2 + 
       timeseries3[[t]]*source3), DataReversed -> True, 
     ColorFunction -> "SunsetColors", ColorFunctionScaling -> False, 
     PlotRangePadding -> None];
   Graphics3D[{
     Texture[texture], 
     Polygon[{{-1.5, 2, -1.5}, {-1.5, 2, 1.5}, {1.5, 2, 1.5}, {1.5, 
        2, -1.5}}, 
      VertexTextureCoordinates -> {{0, 0}, {1, 0}, {1, 1}, {0, 1}}],
     Texture[sourceplot], 
     Polygon[{{-1.5, 5, -1.5}, {-1.5, 5, 1.5}, {1.5, 5, 1.5}, {1.5, 
        5, -1.5}}, 
      VertexTextureCoordinates -> {{0, 0}, {1, 0}, {1, 1}, {0, 1}}]
     , Black, Thick, 
     Line[{{-1.5, 2, -1.5}, {-1.5, 2, 1.5}, {1.5, 2, 1.5}, {1.5, 
        2, -1.5}, {-1.5, 2, -1.5}}], 
     Texture[s], 
     Polygon[{{-1.5, -1, -1.5}, {-1.5, -1, 1.5}, {1.5, -1, 
        1.5}, {1.5, -1, -1.5}}, 
      VertexTextureCoordinates -> {{0, 0}, {1, 0}, {1, 1}, {0, 1}}]
     }, PlotRange -> {{-2, 2}, {-1.5, 5}, {-2, 2}}, 
    ViewPoint -> {-1.3, - 2.4, 2.}, Boxed -> False, 
    Lighting -> "Neutral", Background -> White]
   , {t, 1, 100, 1}];

Export["path/filename.mp4",
 Join[frames1, Reverse[frames1], frames2, Reverse[frames2], frames3, 
  Reverse[frames3], frames4, Reverse[frames4], frames5]
 , "AnimationRepetitions" -> \[Infinity], "DisplayDurations" -> 0.1]

Licensing

I, the copyright holder of this work, hereby publish it under the following license:
Creative Commons CC-Zero This file is made available under the Creative Commons CC0 1.0 Universal Public Domain Dedication.
The person who associated a work with this deed has dedicated the work to the public domain by waiving all of their rights to the work worldwide under copyright law, including all related and neighboring rights, to the extent allowed by law. You can copy, modify, distribute and perform the work, even for commercial purposes, all without asking permission.

Category:CC-Zero#Incoherent%20sum%20of%20speckles.webm
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