Graph-cut and pairwise MRF












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I try to use graph-cut method but I got some trouble with it. I want to segment an image into foreground and background. For each pixel $x$, I got the probability that it belongs to the background $p(x|phi_b)$ and to the foreground $p(x|phi_f)$ by kernel density estimation (KDE). Here is the log-posterior :



$$ log p(mathcal{L}|x) = left( sum^N_{i=1} sum^N_{j=1} lambda(l_il_j + (1-l_i)(1-l_j)) right) + sum^N_{i=1} logleft( frac{p(x_i|phi_f)}{p(x_i|phi_b)} right) l_i $$



where $mathcal{L} = [l_1...L_N]$, $N$ is the number of pixel in the image.



If I understand, the first term is the pairwise cost, for smoothness and determine the weight on edges between a pixel and its neighbors. According to the equation, I put lambda as a weight on each edges.



The second term is the unary cost and determine the weight on edges between a pixel and the source and the sink. Here, the weight between a pixel and the source is the same that between the pixel and the sink ? Am I right ?



Thanks










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    1












    $begingroup$


    I try to use graph-cut method but I got some trouble with it. I want to segment an image into foreground and background. For each pixel $x$, I got the probability that it belongs to the background $p(x|phi_b)$ and to the foreground $p(x|phi_f)$ by kernel density estimation (KDE). Here is the log-posterior :



    $$ log p(mathcal{L}|x) = left( sum^N_{i=1} sum^N_{j=1} lambda(l_il_j + (1-l_i)(1-l_j)) right) + sum^N_{i=1} logleft( frac{p(x_i|phi_f)}{p(x_i|phi_b)} right) l_i $$



    where $mathcal{L} = [l_1...L_N]$, $N$ is the number of pixel in the image.



    If I understand, the first term is the pairwise cost, for smoothness and determine the weight on edges between a pixel and its neighbors. According to the equation, I put lambda as a weight on each edges.



    The second term is the unary cost and determine the weight on edges between a pixel and the source and the sink. Here, the weight between a pixel and the source is the same that between the pixel and the sink ? Am I right ?



    Thanks










    share|cite|improve this question











    $endgroup$















      1












      1








      1





      $begingroup$


      I try to use graph-cut method but I got some trouble with it. I want to segment an image into foreground and background. For each pixel $x$, I got the probability that it belongs to the background $p(x|phi_b)$ and to the foreground $p(x|phi_f)$ by kernel density estimation (KDE). Here is the log-posterior :



      $$ log p(mathcal{L}|x) = left( sum^N_{i=1} sum^N_{j=1} lambda(l_il_j + (1-l_i)(1-l_j)) right) + sum^N_{i=1} logleft( frac{p(x_i|phi_f)}{p(x_i|phi_b)} right) l_i $$



      where $mathcal{L} = [l_1...L_N]$, $N$ is the number of pixel in the image.



      If I understand, the first term is the pairwise cost, for smoothness and determine the weight on edges between a pixel and its neighbors. According to the equation, I put lambda as a weight on each edges.



      The second term is the unary cost and determine the weight on edges between a pixel and the source and the sink. Here, the weight between a pixel and the source is the same that between the pixel and the sink ? Am I right ?



      Thanks










      share|cite|improve this question











      $endgroup$




      I try to use graph-cut method but I got some trouble with it. I want to segment an image into foreground and background. For each pixel $x$, I got the probability that it belongs to the background $p(x|phi_b)$ and to the foreground $p(x|phi_f)$ by kernel density estimation (KDE). Here is the log-posterior :



      $$ log p(mathcal{L}|x) = left( sum^N_{i=1} sum^N_{j=1} lambda(l_il_j + (1-l_i)(1-l_j)) right) + sum^N_{i=1} logleft( frac{p(x_i|phi_f)}{p(x_i|phi_b)} right) l_i $$



      where $mathcal{L} = [l_1...L_N]$, $N$ is the number of pixel in the image.



      If I understand, the first term is the pairwise cost, for smoothness and determine the weight on edges between a pixel and its neighbors. According to the equation, I put lambda as a weight on each edges.



      The second term is the unary cost and determine the weight on edges between a pixel and the source and the sink. Here, the weight between a pixel and the source is the same that between the pixel and the sink ? Am I right ?



      Thanks







      graph-theory computer-science image-processing computer-vision






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      edited Dec 11 '18 at 18:08







      mnchapel

















      asked Dec 11 '18 at 8:44









      mnchapelmnchapel

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