1 ###################################################################### |
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2 # Predictive online PDPS for optical flow with unknown velocity field |
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3 ###################################################################### |
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4 |
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5 __precompile__() |
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6 |
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7 module AlgorithmBothNL |
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8 |
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9 identifier = "pdps_unknown_nl" |
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10 |
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11 |
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12 using Printf |
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13 |
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14 using AlgTools.Util |
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15 import AlgTools.Iterate |
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16 using ImageTools.Gradient |
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17 |
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18 using ..OpticalFlow: ImageSize, |
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19 Image, |
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20 Gradient, |
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21 DisplacementConstant, |
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22 DisplacementFull, |
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23 pdflow!, |
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24 pointwise_gradiprod_2d!, |
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25 pointwise_gradiprod_2dᵀ!, |
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26 filter_hs |
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27 |
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28 using ..Algorithm: step_lengths |
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29 |
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30 ############# |
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31 # Data types |
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32 ############# |
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33 |
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34 struct Primal{DisplacementT} |
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35 x :: Image |
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36 u :: DisplacementT |
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37 end |
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38 |
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39 function Base.similar(x::Primal{DisplacementT}) where DisplacementT |
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40 return Primal{DisplacementT}(Base.similar(x.x), Base.similar(x.u)) |
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41 end |
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42 |
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43 function Base.copy(x::Primal{DisplacementT}) where DisplacementT |
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44 return Primal{DisplacementT}(Base.copy(x.x), Base.copy(x.u)) |
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45 end |
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46 |
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47 struct Dual |
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48 tv :: Gradient |
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49 flow :: Image |
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50 end |
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51 |
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52 function Base.similar(y::Dual) |
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53 return Dual(Base.similar(y.tv), Base.similar(y.flow)) |
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54 end |
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55 |
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56 function Base.copy(y::Dual) |
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57 return Dual(Base.copy(y.tv), Base.copy(y.flow)) |
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58 end |
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59 |
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60 ######################### |
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61 # Iterate initialisation |
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62 ######################### |
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63 |
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64 function init_primal(xinit::Image, ::Type{DisplacementConstant}) |
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65 return Primal{DisplacementConstant}(xinit, zeros(2)) |
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66 end |
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67 |
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68 function init_primal(xinit::Image, ::Type{DisplacementFull}) |
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69 return Primal{DisplacementFull}(xinit, zeros(2, size(xinit)...)) |
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70 end |
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71 |
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72 function init_rest(x::Primal{DisplacementT}) where DisplacementT |
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73 imdim=size(x.x) |
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74 |
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75 y = Dual(zeros(2, imdim...), zeros(imdim)) |
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76 Δx = copy(x) |
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77 Δy = copy(y) |
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78 x̄ = copy(x) |
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79 |
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80 return x, y, Δx, Δy, x̄ |
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81 end |
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82 |
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83 function init_iterates( :: Type{DisplacementT}, |
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84 xinit::Primal{DisplacementT}) where DisplacementT |
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85 return init_rest(copy(xinit)) |
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86 end |
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87 |
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88 function init_iterates( :: Type{DisplacementT}, xinit::Image) where DisplacementT |
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89 return init_rest(init_primal(copy(xinit), DisplacementT)) |
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90 end |
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91 |
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92 function init_iterates( :: Type{DisplacementT}, dim::ImageSize) where DisplacementT |
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93 return init_rest(init_primal(zeros(dim...), DisplacementT)) |
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94 end |
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95 |
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96 ############################################## |
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97 # Weighting for different displacements types |
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98 ############################################## |
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99 |
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100 norm²weight( :: Type{DisplacementConstant}, sz ) = prod(sz) |
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101 norm²weight( :: Type{DisplacementFull}, sz ) = 1 |
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102 |
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103 ############ |
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104 # Algorithm |
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105 ############ |
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106 |
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107 function solve( :: Type{DisplacementT}; |
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108 dim :: ImageSize, |
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109 iterate = AlgTools.simple_iterate, |
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110 params::NamedTuple) where DisplacementT |
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111 |
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112 ###################### |
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113 # Initialise iterates |
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114 ###################### |
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115 |
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116 x, y, Δx, Δy, x̄ = init_iterates(DisplacementT, dim) |
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117 init_data = (params.init == :data) |
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118 |
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119 # … for tracking cumulative movement |
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120 if DisplacementT == DisplacementConstant |
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121 ucumul = [0.0, 0.0] |
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122 else |
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123 ucumul = [NaN, NaN] |
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124 end |
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125 |
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126 ############################################# |
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127 # Extract parameters and set up step lengths |
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128 ############################################# |
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129 |
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130 α, ρ, λ, θ, T = params.α, params.ρ, params.λ, params.θ, params.timestep |
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131 R_K² = max(∇₂_norm₂₂_est², ∇₂_norm₂∞_est²*params.dynrange^2) |
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132 γ = min(1, λ*norm²weight(DisplacementT, size(x.x))) |
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133 τ, σ, σ̃, ρ̃ = step_lengths(params, γ, R_K²) |
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134 |
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135 kernel = params.kernel |
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136 |
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137 #################### |
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138 # Run the algorithm |
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139 #################### |
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140 |
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141 b_next_filt=nothing |
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142 |
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143 v = iterate(params) do verbose :: Function, |
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144 b :: Image, |
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145 🚫unused_v_known :: DisplacementT, |
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146 b_next :: Image |
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147 |
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148 #################################### |
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149 # Smooth data for Horn–Schunck term |
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150 #################################### |
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151 |
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152 b_filt, b_next_filt = filter_hs(b, b_next, b_next_filt, kernel) |
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153 |
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154 ############################ |
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155 # Construct K for this step |
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156 ############################ |
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157 |
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158 K! = (yʹ, xʹ) -> begin |
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159 # Optical flow part |
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160 @. yʹ.flow = b_filt |
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161 flow!(yʹ.flow, Δx.x, xʹ.u) |
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162 @. yʹ.flow = yʹ.flow - b_next_filt |
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163 # TV part |
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164 ∇₂!(yʹ.tv, xʹ.x) |
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165 end |
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166 Kᵀ! = (xʹ, yʹ) -> begin |
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167 # Optical flow part: ∇b_k ⋅ y |
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168 # |
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169 # TODO: This really should depend x.u, but x.u is zero. |
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170 # |
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171 pointwise_gradiprod_2dᵀ!(xʹ.u, yʹ.flow, b_filt) |
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172 # TV part |
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173 ∇₂ᵀ!(xʹ.x, yʹ.tv) |
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174 end |
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175 |
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176 ################## |
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177 # Prediction step |
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178 ################## |
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179 |
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180 if init_data |
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181 x .= b |
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182 init_data = false |
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183 end |
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184 |
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185 pdflow!(x.x, Δx.x, y.tv, Δy.tv, y.flow, Δy.flow, x.u, params.dual_flow) |
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186 |
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187 # Predict zero displacement |
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188 x.u .= 0 |
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189 if params.prox_predict |
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190 K!(Δy, x) |
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191 @. y.tv = (y.tv + σ̃*Δy.tv)/(1 + σ̃*(ρ̃+ρ/α)) |
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192 proj_norm₂₁ball!(y.tv, α) |
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193 @. y.flow = (y.flow+σ̃*Δy.flow)/(1+σ̃*(ρ̃+1/θ)) |
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194 end |
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195 |
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196 ############ |
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197 # PDPS step |
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198 # |
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199 # NOTE: For DisplacementConstant, the x.u update is supposed to be with |
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200 # respect to the 𝟙^*𝟙 norm/inner product that makes the norm equivalent |
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201 # to full-space norm when restricted to constant displacements. Since |
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202 # `OpticalFlow.pointwise_gradiprod_2dᵀ!` already uses this inner product, |
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203 # and the λ-weighted term in the problem is with respect to this norm, |
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204 # all the norm weights disappear in this update. |
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205 ############ |
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206 |
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207 Kᵀ!(Δx, y) # primal step: |
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208 @. x̄.x = x.x # | save old x for over-relax |
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209 @. x̄.u = x.u # | |
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210 @. x.x = (x.x-τ*(Δx.x-b))/(1+τ) # | prox |
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211 @. x.u = (x.u-τ*Δx.u)/(1+τ*λ) # | |
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212 @. x̄.x = 2x.x - x̄.x # over-relax |
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213 @. x̄.u = 2x.u - x̄.u # | |
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214 K!(Δy, x̄) # dual step: y |
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215 @. y.tv = (y.tv + σ*Δy.tv)/(1 + σ*ρ/α) # | |
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216 proj_norm₂₁ball!(y.tv, α) # | prox |
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217 @. y.flow = (y.flow+σ*Δy.flow)/(1+σ/θ) |
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218 |
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219 if DisplacementT == DisplacementConstant |
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220 ucumul .+= x.u |
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221 end |
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222 |
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223 ######################################################## |
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224 # Give function value and cumulative movement if needed |
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225 ######################################################## |
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226 v = verbose() do |
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227 K!(Δy, x) |
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228 value = (norm₂²(b-x.x)/2 + θ*norm₂²(Δy.flow) |
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229 + λ*norm₂²(x.u)/2 + α*γnorm₂₁(Δy.tv, ρ)) |
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230 |
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231 value, x.x, ucumul, nothing |
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232 end |
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233 |
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234 return v |
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235 end |
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236 |
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237 return x, y, v |
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238 end |
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239 |
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240 end # Module |
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241 |
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242 |
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