图像处理之霍夫变换圆检测算法.docx

图像处理之霍夫变换圆检测算法一:霍夫变换检测圆的数学原理根据极坐标,圆上任意一点的坐标可以表示为如上形式, 所以对于任意一个圆, 假设中心像素点p(x0, y0)像素点已知, 圆半径已知,则旋转360由极坐标方程可以得到每个点上得坐标同样,如果只是知道图像上像素点, 圆半径,旋转360则中心点处的坐标值必定最强.这正是霍夫变换检测圆的数学原理.二:算法流程该算法大致可以分为以下几个步骤三:运行效果图像从空间坐标变换到极坐标效果, 最亮一点为圆心.图像从极坐标变换回到空间坐标,检测结果显示:四:关键代码解析个人觉得这次注释已经是非常的详细啦,而且我写的还是中文注释javaview plaincopy1. /*2. *霍夫变换处理-检测半径大小符合的圆的个数3. *1.将图像像素从2D空间坐标转换到极坐标空间4. *2.在极坐标空间中归一化各个点强度，使之在0255之间5. *3.根据极坐标的R值与输入参数(圆的半径)相等，寻找2D空间的像素点6. *4.对找出的空间像素点赋予结果颜色(红色)7. *5.返回结果2D空间像素集合8. *returnint9. */10. publicintprocess()11. 12. /对于圆的极坐标变换来说，我们需要360度的空间梯度叠加值13. acc=newintwidth*height;14. for(inty=0;yheight;y+)15. for(intx=0;xwidth;x+)16. accy*width+x=0;17. 18. 19. intx0,y0;20. doublet;21. for(intx=0;xwidth;x+)22. for(inty=0;yheight;y+)23. 24. if(inputy*width+x&0xff)=255)25. 26. for(inttheta=0;theta360;theta+)27. t=(theta*3.14159265)/180;/角度值02*PI28. x0=(int)Math.round(x-r*Math.cos(t);29. y0=(int)Math.round(y-r*Math.sin(t);30. if(x00&y00)31. accx0+(y0*width)+=1;32. 33. 34. 35. 36. 37. 38. /nownormaliseto255andputinformatforapixelarray39. intmax=0;40. 41. /Findmaxaccvalue42. for(intx=0;xwidth;x+)43. for(inty=0;ymax)46. max=accx+(y*width);47. 48. 49. 50. 51. /根据最大值，实现极坐标空间的灰度值归一化处理52. intvalue;53. for(intx=0;xwidth;x+)54. for(inty=0;yheight;y+)55. value=(int)(double)accx+(y*width)/(double)max)*255.0);56. accx+(y*width)=0xff000000|(value16|value8|value);57. 58. 59. 60. /绘制发现的圆61. findMaxima();62. System.out.println(done);63. returnoutput;64. 完整的算法源代码, 已经全部的加上注释javaview plaincopy1. packagecom.gloomyfish.image.transform.hough;2. /*3. *4. *传入的图像为二值图像，背景为黑色，目标前景颜色为为白色5. *authorgloomyfish6. *7. */8. publicclassCircleHough9. 10. privateintinput;11. privateintoutput;12. privateintwidth;13. privateintheight;14. privateintacc;15. privateintaccSize=1;16. privateintresults;17. privateintr;/圆周的半径大小18. 19. publicCircleHough()20. System.out.println(HoughCircleDetection.);21. 22. 23. publicvoidinit(intinputIn,intwidthIn,intheightIn,intradius)24. r=radius;25. width=widthIn;26. height=heightIn;27. input=newintwidth*height;28. output=newintwidth*height;29. input=inputIn;30. for(inty=0;yheight;y+)31. for(intx=0;xwidth;x+)32. outputx+(width*y)=0xff000000;/默认图像背景颜色为黑色33. 34. 35. 36. 37. publicvoidsetCircles(intcircles)38. accSize=circles;/检测的个数39. 40. 41. /*42. *霍夫变换处理-检测半径大小符合的圆的个数43. *1.将图像像素从2D空间坐标转换到极坐标空间44. *2.在极坐标空间中归一化各个点强度，使之在0255之间45. *3.根据极坐标的R值与输入参数(圆的半径)相等，寻找2D空间的像素点46. *4.对找出的空间像素点赋予结果颜色(红色)47. *5.返回结果2D空间像素集合48. *returnint49. */50. publicintprocess()51. 52. /对于圆的极坐标变换来说，我们需要360度的空间梯度叠加值53. acc=newintwidth*height;54. for(inty=0;yheight;y+)55. for(intx=0;xwidth;x+)56. accy*width+x=0;57. 58. 59. intx0,y0;60. doublet;61. for(intx=0;xwidth;x+)62. for(inty=0;yheight;y+)63. 64. if(inputy*width+x&0xff)=255)65. 66. for(inttheta=0;theta360;theta+)67. t=(theta*3.14159265)/180;/角度值02*PI68. x0=(int)Math.round(x-r*Math.cos(t);69. y0=(int)Math.round(y-r*Math.sin(t);70. if(x00&y00)71. accx0+(y0*width)+=1;72. 73. 74. 75. 76. 77. 78. /nownormaliseto255andputinformatforapixelarray79. intmax=0;80. 81. /Findmaxaccvalue82. for(intx=0;xwidth;x+)83. for(inty=0;ymax)86. max=accx+(y*width);87. 88. 89. 90. 91. /根据最大值，实现极坐标空间的灰度值归一化处理92. intvalue;93. for(intx=0;xwidth;x+)94. for(inty=0;yheight;y+)95. value=(int)(double)accx+(y*width)/(double)max)*255.0);96. accx+(y*width)=0xff000000|(value16|value8|value);97. 98. 99. 100. /绘制发现的圆101. findMaxima();102. System.out.println(done);103. returnoutput;104. 105. 106. privateintfindMaxima()107. results=newintaccSize*3;108. intoutput=newintwidth*height;109. 110. /获取最大的前accSize个值111. for(intx=0;xwidth;x+)112. for(inty=0;yresults(accSize-1)*3)117. 118. /addtobottomofarray119. results(accSize-1)*3=value;/像素值120. results(accSize-1)*3+1=x;/坐标X121. results(accSize-1)*3+2=y;/坐标Y122. 123. /shiftupuntilitsinrightplace124. inti=(accSize-2)*3;125. while(i=0)&(resultsi+3resultsi)126. for(intj=0;j3;j+)127. inttemp=resultsi+j;128. resultsi+j=resultsi+3+j;129. resultsi+3+j=temp;130. 131. i=i-3;132. if(i=0;i-)142. drawCircle(resultsi*3,resultsi*3+1,resultsi*3+2);143. 144. returnoutput;145. 146. 147. privatevoidsetPixel(intvalue,intxPos,intyPos)148. /output(yPos*width)+xPos=0xff000000|(value16|value8|value);149. output(yPos*width)+xPos=0xffff0000;150. 151. 152. /drawcircleatxy153. privatevoiddrawCircle(intpix,intxCenter,intyCenter)154. pix=250;/颜色值，默认为白色155. 156. intx,y,r2;157. intradius=r;158. r2=r*r;159. 160. /绘制圆的上下左右四个点161. setPixel(pix,xCenter,yCenter+radius);162. setPixel(pix,xCenter,yCenter-radius);163. setPixel(pix,xCenter+radius,yCenter);164. setPixel(pix,xCenter-radius,yCenter);165. 166. y=radius;167. x=1;168. y=(int)(Math.sqrt(r2-1)+0.5);169. 170. /边缘填充算法，其实可以直接对循环所有像素，计算到做中心点距离来做171. /这个方法是别人写的，发现超赞，超好！172. while(xy)173. setPixel(pix,xCenter+x,yCenter+y);174. setPixel(pix,xCenter+x,yCenter-y);175. setPixel(pix,xCenter-x,yCenter+y);176. setPixel(pix,xCenter-x,yCenter-y);177. setPixel(pix,xCenter+y,yCenter+x);178. setPixel(pix,xCenter+y,yCenter-x);179. setPixel(pix,xCenter-y,yCenter+x);180. setPixel(pix,xCenter-y,yCenter-x);181. x+=1;182. y=(int)(Math.sqrt(r2-x*x)+0.5);183. 184. if(x=y)185. setPixel(pix,xCenter+x,yCenter+y);186. setPixel(pix,xCenter+x,yCenter-y);187. setPixel(pix,xCenter-x,yCenter+y);188. setPixel(pix,xCenter-x,yCenter-y);189. 190. 191. 192. publicintgetAcc()193. returnacc;194. 195. 196. 测试的UI类:javaview plaincopy1. packagecom.gloomyfish.image.transform.hough;2. 3. importjava.awt.BorderLayout;4. importjava.awt.Color;5. importjava.awt.Dimension;6. importjava.awt.FlowLayout;7. importjava.awt.Graphics;8. importjava.awt.Graphics2D;9. importjava.awt.GridLayout;10. importjava.awt.event.ActionEvent;11. importjava.awt.event.ActionListener;12. importjava.awt.image.BufferedImage;13. importjava.io.File;14. 15. importjavax.imageio.ImageIO;16. importjavax.swing.BorderFactory;17. importjavax.swing.JButton;18. importjavax.swing.JFrame;19. importjavax.swing.JPanel;20. importjavax.swing.JSlider;21. importjavax.swing.event.ChangeEvent;22. importjavax.swing.event.ChangeListener;23. 24. publicclassHoughUIextendsJFrameimplementsActionListener,ChangeListener25. /*26. *27. */28. publicstaticfinalStringCMD_LINE=LineDetection;29. publicstaticfinalStringCMD_CIRCLE=CircleDetection;30. privatestaticfinallongserialVersionUID=1L;31. privateBufferedImagesourceImage;32. /privateBufferedImagehoughImage;33. privateBufferedImageresultImage;34. privateJButtonlineBtn;35. privateJButtoncircleBtn;36. privateJSliderradiusSlider;37. privateJSlidernumberSlider;38. publicHoughUI(StringimagePath)39. 40. super(GloomyFish-ImageProcessDemo);41. try42. Filefile=newFile(imagePath);43. sourceImage=ImageIO.read(file);44. catch(Exceptione)45. e.printStackTrace();46. 47. initComponent();48. 49. 50. privatevoidinitComponent()51. intRADIUS_MIN=1;52. intRADIUS_INIT=1;53. intRADIUS_MAX=51;54. lineBtn=newJButton(CMD_LINE);55. circleBtn=newJButton(CMD_CIRCLE);56. radiusSlider=newJSlider(JSlider.HORIZONTAL,RADIUS_MIN,RADIUS_MAX,RADIUS_INIT);57. radiusSlider.setMajorTickSpacing(10);58. radiusSlider.setMinorTickSpacing(1);59. radiusSlider.setPaintTicks(true);60. radiusSlider.setPaintLabels(true);61. numberSlider=newJSlider(JSlider.HORIZONTAL,RADIUS_MIN,RADIUS_MAX,RADIUS_INIT);62. numberSlider.setMajorTickSpacing(10);63. numberSlider.setMinorTickSpacing(1);64. numberSlider.setPaintTicks(true);65. numberSlider.setPaintLabels(true);66. 67. JPanelsliderPanel=newJPanel();68. sliderPanel.setLayout(newGridLayout(1,2);69. sliderPanel.setBorder(BorderFactory.createTitledBorder(Settings:);70. sliderPanel.add(radiusSlider);71. sliderPanel.add(numberSlider);72. JPanelbtnPanel=newJPanel();73. btnPanel.setLayout(newFlowLayout(FlowLayout.RIGHT);74. btnPanel.add(lineBtn);75. btnPanel.add(circleBtn);76. 77. 78. JPanelimagePanel=newJPanel()79. 80. privatestaticfinallongserialVersionUID=1L;81. 82. protectedvoidpaintComponent(Graphicsg)83. if(sourceImage!=null)84. 85. Graphics2Dg2=(Graphics2D)g;86. g2.drawImage(sourceImage,10,10,sourceImage.getWidth(),sourceImage.getHeight(),null);87. g2.setPaint(Color.BLUE);88. g2.drawString(原图,10,sourceImage.getHeight()+30);89. if(resultImage!=null)90. 91. g2.drawImage(resultImage,resultImage.getWidth()+20,10,resultImage.getWidth(),resultImage.getHeight(),null);92. g2.drawString(最终结果,红色是检测结果,resultImage.getWidth()+40,sourceImage.getHeight()+30);93. 94. 95. 96. 97. ;98. this.getContentPane().setLayout(newBorderLayout();99. this.getContentPane().add(sliderPanel,BorderLayout.NORTH);100. this.getContentPane().add(btnPanel,BorderLayout.SOUTH);101. this.getContentPane().add(imagePanel,BorderLayout.CENTER);102. 103. /setuplistener104. this.lineBtn.addActionListener(this);105. this.circleBtn.addActionListener(this);106. this.numberSlider.addChangeListener(this);107. this.radiusSlider.addChangeListener(this);108. 109. 110. publicstaticvoidmain(Stringargs)111. 112. StringfilePath=System.getProperty(user.home)+/Desktop/+zhigang/hough-test.png