在 2009年10月6日星期二UTC+8下午8时18分02秒，Sandeep 写道：
> Hi all,
>
> I am trying to implement a shadow removal algorithm in matlab. I follow the paper
> written by Mr.Graham.Finalyson i.e, "Shadow removal using Entropy minimization".
> First of all i am trying to get 1-D illuminant invariant image by assuming that we
> know the projection angle. I took some known images from the above mentioned
> paper so that i know the projection angle and there is no need of entropy calculation.
> The program which wrote works with some images and seems to be failed with some images. Please help me if some one has some experience with this algorithm. I am appending small part of my matlab code which is written to produce a 1-D illumination invariant image.
> ------------------------------------------------------------------------------------------------------------------
>
> I = imread('file1.tiff');
> J = im2double(I);
>
> R = J(:,:,1);
> G = J(:,:,2);
> B = J(:,:,3);
>
> [len,wid] = size(R);
>
> % Generation of 2-D Log Chromaticity Image.
> for i = 1:len
> for j = 1:wid
> if ((R(i,j)*G(i,j)*B(i,j))~= 0)
> c1(i,j) = R(i,j)/((R(i,j)*G(i,j)*B(i,j))^(1/3));
> c2(i,j) = G(i,j)/((R(i,j)*G(i,j)*B(i,j))^(1/3));
> c3(i,j) = B(i,j)/((R(i,j)*G(i,j)*B(i,j))^(1/3));
> else
> c1(i,j) = 1;
> c2(i,j) = 1;
> c3(i,j) = 1;
> end
> end
> end
>
> rho1 = mat2gray(log(c1));
> rho2 = mat2gray(log(c2));
> rho3 = mat2gray(log(c3));
>
> X1 = mat2gray(rho1*1/(sqrt(2)) - rho2*1/(sqrt(2))); %(1/sqrt(2); -1/sqrt(2); 0)
> X2 = mat2gray(rho1*1/(sqrt(6)) + rho2*1/(sqrt(6)) - rho3*2/(sqrt(6))); %(1/sqrt(6); 1/sqrt(6); -2/sqrt(6))
>
> theta = 120;
>
> InvariantImage = cos(theta*pi/180)*X1 + sin(theta*pi/180)*X2;
>
> -----------------------------------------------------------------------------------------------------
>
> Thank you all,
> Sandeep P
Hi to all,
I am working on a shadow removal experiment, so I'm wondering if you know where to download the images in the paper you mentioned? Many thanks.![]()
> Hi all,
>
> I am trying to implement a shadow removal algorithm in matlab. I follow the paper
> written by Mr.Graham.Finalyson i.e, "Shadow removal using Entropy minimization".
> First of all i am trying to get 1-D illuminant invariant image by assuming that we
> know the projection angle. I took some known images from the above mentioned
> paper so that i know the projection angle and there is no need of entropy calculation.
> The program which wrote works with some images and seems to be failed with some images. Please help me if some one has some experience with this algorithm. I am appending small part of my matlab code which is written to produce a 1-D illumination invariant image.
> ------------------------------------------------------------------------------------------------------------------
>
> I = imread('file1.tiff');
> J = im2double(I);
>
> R = J(:,:,1);
> G = J(:,:,2);
> B = J(:,:,3);
>
> [len,wid] = size(R);
>
> % Generation of 2-D Log Chromaticity Image.
> for i = 1:len
> for j = 1:wid
> if ((R(i,j)*G(i,j)*B(i,j))~= 0)
> c1(i,j) = R(i,j)/((R(i,j)*G(i,j)*B(i,j))^(1/3));
> c2(i,j) = G(i,j)/((R(i,j)*G(i,j)*B(i,j))^(1/3));
> c3(i,j) = B(i,j)/((R(i,j)*G(i,j)*B(i,j))^(1/3));
> else
> c1(i,j) = 1;
> c2(i,j) = 1;
> c3(i,j) = 1;
> end
> end
> end
>
> rho1 = mat2gray(log(c1));
> rho2 = mat2gray(log(c2));
> rho3 = mat2gray(log(c3));
>
> X1 = mat2gray(rho1*1/(sqrt(2)) - rho2*1/(sqrt(2))); %(1/sqrt(2); -1/sqrt(2); 0)
> X2 = mat2gray(rho1*1/(sqrt(6)) + rho2*1/(sqrt(6)) - rho3*2/(sqrt(6))); %(1/sqrt(6); 1/sqrt(6); -2/sqrt(6))
>
> theta = 120;
>
> InvariantImage = cos(theta*pi/180)*X1 + sin(theta*pi/180)*X2;
>
> -----------------------------------------------------------------------------------------------------
>
> Thank you all,
> Sandeep P
Hi to all,
I am working on a shadow removal experiment, so I'm wondering if you know where to download the images in the paper you mentioned? Many thanks.