书籍翻拍展平方案

• 畸变校正基本原理
  • 畸变校正的关键在于确定基点和畸变方程
  • 基点：书本畸变是水平方向的畸变，以书本中间的分界线为基点
  • 畸变方程：用书本的边界线来确定

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• 书籍翻拍特征分析
• 书本的颜色信息有各种各样的，会影响二值化信息
• 书本厚薄会影响边界分界点的表现形式
  • 厚书两边会有梯度
  • 薄书中间位置会有最大最小值或是平行直线
• 书本的摆放角度会影响最终的表达式

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• 执行方案流程
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• 代码实现
  1. 获取图像并灰度化

     %read image to cache
     imgSrc=imread('G:\01_work_project\06book_image\01source\厚薄\PIC_0005_Left.jpg');
     %grayscale image with Max(R,G,B)
     [srcrow srccol]=size(imgSrc);
     for i=1:srcrow
         for j=1:srccol/3
             imgGray(i,j)=max(imgSrc(i,j,1),max(imgSrc(i,j,2),imgSrc(i,j,3)));
         end
     end
     imwrite(imgGray,'E:\01灰度图.jpg');
     figure(2);subplot(111);imshow(imgGray);title('灰度图');
     

     　　

  2. 二值化

     %二值化
     thresh=30/255;
     imgbw=im2bw(imgGray,thresh);
     imgbw=medfilt2(imgbw,[7 7]);
     imwrite(imgbw,'E:\02二值图.jpg');figure(3);subplot(111);imshow(imgbw);title('二值图');
     

     　　

  3. 边缘检测

     imgEdge=edge(imgbw,'canny');
     imwrite(imgEdge,'E:\03canny边缘检测.jpg');figure(4);subplot(111);imshow(imgEdge);title('canny算子边缘检测');
     imgsmalledeg=bwmorph(imgEdge,'thin',Inf);
     imwrite(imgsmalledeg,'E:\04骨架.jpg');figure(5);subplot(111);imshow(imgsmalledeg);title('imgsmalledeg');
     

     　　

  4. 确界曲线

     [row col]=size(imgsmalledeg);
     imgconfine=zeros(row,col);
     ytop(col)=0;
     ybot(col)=0;
     for j=20:col-20
     	for i=20:row/4
     		if imgsmalledeg(i,j)==1
     			imgconfine(i,j)=255;
     			ytop(j)=i;
     			break;
     		end
     	end
     	for i=row-20:-1:row/4*3
     		if imgsmalledeg(i,j)==1
     			imgconfine(i,j)=255;
     			ybot(j)=i;
     			break;
     		end
     	end
     end
     imwrite(imgconfine,'E:\05结构点.jpg');figure(5);subplot(111);imshow(imgconfine);title('imgconfine');
     

     　　

  5. 寻找中间分界线

     %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
     %寻找右角点
     %求出数值统计信息——————1.平均值2.变化率3.变化绝对值4.
     top_dvalue(col-500)=0;
     top_mvalue(col-500)=0;
     top_ratevalue(col-500)=0;
     bot_ratevalue(col-500)=0;
     top_5poing(col-500)=0;
     for i=col-25:-1:col-500
       top_mvalue(i)=(ytop(i)+ytop(i-1)+ytop(i-2)+ytop(i+1)+ytop(i+2))/5;
       top_ratevalue(i)=abs((ytop(i+5)-ytop(i))-(ytop(i)-ytop(i-5)));
       bot_ratevalue(i)=abs((ybot(i+5)-ybot(i))-(ybot(i)-ybot(i-5)));
       top_5poing(i)=ytop(i)-ytop(i-5);
     end
     for i=col-25:-1:col-500
      top_dvalue(i)=ytop(i)-top_mvalue(i);
     end
     figure(7);subplot(221),bar(top_mvalue);
     figure(7);subplot(222),bar(top_5poing);
     figure(7);subplot(223),bar(top_ratevalue);
     figure(7);subplot(224),bar(top_dvalue);
     %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

     %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
     Maxratetop=0;
     Maxratebot=0;
     for i=col-25:-1:col-500
      if top_ratevalue(i)>Maxratetop
       Maxratetop=top_ratevalue(i);
       Mattateitop=i;
      end
      if bot_ratevalue(i)>Maxratebot
       Maxratebot=bot_ratevalue(i);
       Mattateibot=i;
      end
     end

     imgright=imgconfine;
     for j=1:col
      for i=1:row
       if j==Mattateitop
        imgright(i,j)=255;
       end
       if j==Mattateibot
        imgright(i,j)=64;
       end
      end
     end
     imwrite(imgright,'E:\06右上点.jpg');
     figure(8);subplot(111);imshow(imgright);title('imgright');
     %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

     　　

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• 测试调整