Full Code of candycat1992/PencilDrawing for AI

Repository: candycat1992/PencilDrawing
Branch: master
Commit: bca965d1c92a
Files: 6
Total size: 8.2 KB

Directory structure:
gitextract__zisyvfe/

├── GenPencil.m
├── GenStroke.m
├── GenToneMap.m
├── PencilDrawing.m
├── README.md
└── demo.m

================================================
FILE CONTENTS
================================================

================================================
FILE: GenPencil.m
================================================
function T = GenPencil(im, P, J)
% ==============================================
%   Compute the pencil map 'T'
%  
%   Paras:
%   @im        : input image ranging value from 0 to 1.
%   @P         : the pencil texture.
%   @J         : the tone map.
%

    %% Parameters
    theta = 0.2;
    
    [H, W, ~] = size(im);

    %% Initialization
    P = imresize(P, [H, W]);
    P = reshape(P, H*W, 1);
    logP = log(P);
    logP = spdiags(logP, 0, H*W, H*W);
    
    J = imresize(J, [H, W]);
    J = reshape(J, H*W, 1);
    logJ = log(J);
    
    e = ones(H*W, 1);
    Dx = spdiags([-e, e], [0, H], H*W, H*W);
    Dy = spdiags([-e, e], [0, 1], H*W, H*W);
    
    %% Compute matrix A and b
    A = theta * (Dx * Dx' + Dy * Dy') + (logP)' * logP;
    b = (logP)' * logJ;
    
    %% Conjugate gradient
    beta = pcg(A, b, 1e-6, 60);
    
    %% Compute the result
    beta = reshape(beta, H, W);
    
    P = reshape(P, H, W);
    
    T = P .^ beta;
end

================================================
FILE: GenStroke.m
================================================
function S = GenStroke(im, ks, width, dirNum)
% ==============================================
%   Compute the stroke structure 'S'
%  
%   Paras:
%   @im        : input image ranging value from 0 to 1.
%   @ks        : kernel size.
%   @width     : width of the strocke
%   @dirNum    : number of directions.
%
    
    %% Initialization
    [H, W, ~] = size(im);
    
    %% Smoothing
    im = medfilt2(im, [3 3]);
    
    %% Image gradient
    imX = [abs(im(:,1:(end-1)) - im(:,2:end)),zeros(H,1)];
    imY = [abs(im(1:(end-1),:) - im(2:end,:));zeros(1,W)];  
    imEdge = imX + imY;

    %% Convolution kernel with horizontal direction 
    kerRef = zeros(ks*2+1);
    kerRef(ks+1,:) = 1;

    %% Classification 
    response = zeros(H,W,dirNum);
    for n = 1 : dirNum
        ker = imrotate(kerRef, (n-1)*180/dirNum, 'bilinear', 'crop');
        response(:,:,n) = conv2(imEdge, ker, 'same');
    end

    [~, index] = max(response,[], 3); 

    %% Create the stroke
    C = zeros(H, W, dirNum);
    for n = 1 : dirNum
        C(:,:,n) = imEdge .* (index == n);
    end

    kerRef = zeros(ks*2+1);
    kerRef(ks+1,:) = 1;
    for n = 1 : width
        if (ks+1-n) > 0
            kerRef(ks+1-n,:) = 1;
        end
        if (ks+1+n) < (ks*2+1)
            kerRef(ks+1+n,:) = 1;
        end
    end
    
    Spn = zeros(H, W, dirNum);
    for n = 1 : dirNum
        ker = imrotate(kerRef, (n-1)*180/dirNum, 'bilinear', 'crop');
        Spn(:,:,n) = conv2(C(:,:,n), ker, 'same');
    end

    Sp = sum(Spn, 3);
    Sp = (Sp - min(Sp(:))) / (max(Sp(:)) - min(Sp(:)));
    S = 1 - Sp;
end

================================================
FILE: GenToneMap.m
================================================
function J = GenToneMap(im)
% ==============================================
%   Compute the tone map 'T'
%  
%   Paras:
%   @im        : input image ranging value from 0 to 1.
%
    
    %% Parameters
    Ub = 225;
    Ua = 105;
    
    Mud = 90;
    
    DeltaB = 9;
    DeltaD = 11;
    
    % groups from dark to light
    % 1st group
    Omega1 = 42;
    Omega2 = 29;
    Omega3 = 29;
    % 2nd group
    Omega1 = 52;
    Omega2 = 37;
    Omega3 = 11;
    % 3rd group
    Omega1 = 76;
    Omega2 = 22;
    Omega3 = 2;
    
    %% Compute the target histgram
    histgramTarget = zeros(256, 1);
    total = 0;
    for ii = 0 : 255
        if ii < Ua || ii > Ub
            p = 0;
        else
            p = 1 / (Ub - Ua);
        end
        
        histgramTarget(ii+1, 1) = (...
            Omega1 * 1/DeltaB * exp(-(255-ii)/DeltaB) + ...
            Omega2 * p + ...
            Omega3 * 1/sqrt(2 * pi * DeltaD) * exp(-(ii-Mud)^2/(2*DeltaD^2))) * 0.01;
        
        total = total + histgramTarget(ii+1, 1);
    end
    histgramTarget(:, 1) = histgramTarget(:, 1)/total;

%     %% Smoothing
%     im = medfilt2(im, [5 5]);
    
    %% Histgram matching
    J = histeq(im, histgramTarget);
    
    %% Smoothing
    G = fspecial('average', 10);
    J = imfilter(J, G,'same');
end

================================================
FILE: PencilDrawing.m
================================================
function I = PencilDrawing(im, ks, width, dirNum, gammaS, gammaI)
% ==============================================
%   Generate the pencil drawing I based on the method described in
%   "Combining Sketch and Tone for Pencil Drawing Production" Cewu Lu, Li Xu, Jiaya Jia 
%   International Symposium on Non-Photorealistic Animation and Rendering (NPAR 2012), June, 2012
%  
%   Paras:
%   @im        : the input image.
%   @ks        : the length of convolution line.
%   @width     : the width of the stroke.
%   @dirNum    : the number of directions.
%   @gammaS    : the darkness of the stroke.
%   @gammaI    : the darkness of the resulted image.
%

    %% Read the image
    im = im2double(im);
    [H, W, sc] = size(im);

    %% Convert from rgb to yuv when nessesary
    if (sc == 3)
        yuvIm = rgb2ycbcr(im);
        lumIm = yuvIm(:,:,1);
    else
        lumIm = im;
    end

    %% Generate the stroke map
    S = GenStroke(lumIm, ks, width, dirNum) .^ gammaS; % darken the result by gamma
%     figure, imshow(S)

    %% Generate the tone map
    J = GenToneMap(lumIm) .^ gammaI; % darken the result by gamma
%     figure, imshow(J)

    %% Read the pencil texture
    P = im2double(imread('pencils/pencil0.jpg'));
    P = rgb2gray(P);

    %% Generate the pencil map
    T = GenPencil(lumIm, P, J);
%     figure, imshow(T)

    %% Compute the result
    lumIm = S .* T;

    if (sc == 3)
        yuvIm(:,:,1) = lumIm;
    %     resultIm = lumIm;
        I = ycbcr2rgb(yuvIm);
    else
        I = lumIm;
    end
end



================================================
FILE: README.md
================================================

# Introduction

Implement the algorithm presented in [1]. You can use the code like below to get a pencil drawing production:

```C++
I = PencilDrawing(im, ks, width, dirNum, gammaS, gammaI);
```

See demo.m for example.

# Parameters

I added some more parameters for better control of the final image.

* **width**

	Control the width of the strokes. See Figure 1 for example.

	![alt text](https://github.com/candycat1992/PencilDrawing/blob/master/results/width0.png) ![alt text](https://github.com/candycat1992/PencilDrawing/blob/master/results/width1.png)

	**Figure 1**: Width of the strokes. left: width = 0; right: width = 2.

* **gammaS**

	Control the darkness of the strokes. See Figure 2 for example.

	![alt text](https://github.com/candycat1992/PencilDrawing/blob/master/results/stroke_dark0.png) ![alt text](https://github.com/candycat1992/PencilDrawing/blob/master/results/stroke_dark1.png)

	**Figure 2**: Gamma of the strokes. left: gammaS = 1.0; right: gammaS = 2.0.

* **gammaI**

	Control the darkness of the final image. See Figure 3 for example.

	![alt text](https://github.com/candycat1992/PencilDrawing/blob/master/results/image_dark0.png) ![alt text](https://github.com/candycat1992/PencilDrawing/blob/master/results/image_dark1.png)

	**Figure 3**: Gamma of the final image. left: gammaI = 1.0; right: gammaI = 0.4.

## Tone Transfer Weights

The paper presented three groups of weights for tone map generation.

1. ![alt text](https://github.com/candycat1992/PencilDrawing/blob/master/project_images/Tex2Img_1448535264.jpg)

2. ![alt text](https://github.com/candycat1992/PencilDrawing/blob/master/project_images/Tex2Img_1448535306.jpg)

3. ![alt text](https://github.com/candycat1992/PencilDrawing/blob/master/project_images/Tex2Img_1448535007.jpg)

These weights will determine the histogram of the tone map. I use the third group by default, which makes the final image lighter. You can change to other groups in GenToneMap.m.

# Folder Organization

* **inputs**

	Include some test images from <a href="http://www.cse.cuhk.edu.hk/leojia/projects/pencilsketch/pencil_drawing.htm" target="_blank">the website </a> of the publishers and other images.

* **pencils**
	
	Include 5 pencil textures for demonstration. I use “pencils/pencil0.jpg” by default. You can change it in PencilDrawing.m.

* **results**

	Include the results generated by my code. Each image may use different parameters.

* **resultsFromPaper**

	Include the results of the paper for comparison. I grabbed them in <a href="http://www.cse.cuhk.edu.hk/leojia/projects/pencilsketch/pencil_drawing.htm" target="_blank">their website</a>.

# Reference

[1] Lu C, Xu L, Jia J. Combining sketch and tone for pencil drawing production[C]//Proceedings of the Symposium on Non-Photorealistic Animation and Rendering. Eurographics Association, 2012: 65-73.


================================================
FILE: demo.m
================================================

im = imread('inputs/15--298.jpg');

I = PencilDrawing(im, 8, 1, 8, 1.0, 1.0);

figure, imshow(I)