Question

我是面向对象编程的新手，它正在显示！

这就是我希望我的程序要做的事情：

显示像这样的黑白图像，除了白色而不是粉红色： [ This is the image I'm using, except white instead of pink ]

使用链代码通过创建blob /链来跟踪图像。每个链是坐标对的ArrayList（坐标对是名为Point2d的类的实例）。每个链的ArrayList都被命名为chain [0]，链1等等。
按S将这些链逐个保存到另一个名为chainlist的ArrayList中。
按R打印出每个链的所有坐标对。

不幸的是，我有两个问题。

每次我将单个链（例如chain[2]）保存到我的链表中时，它会保存所有其他链。所以我只想保存chain[2]中的点数，但这些完全相同的点会被放入chain[1]和chain[0]。
由于“等待数据包134”或其他一些数据包，我的草图不断崩溃。经过很多谷歌，我仍然不知道是什么导致了这一点。

我很遗憾我的代码可能有多乱。我从未接受过正规训练，只是想学习。

// Computes "chain code" to trace edge of a blob.
// This code only traces the first blob found,
// Where "first" is defined as "having a pixel with a lower index" (i.e. higher and to the left).
// For multi-blobs, additional code would be needed to label connected blobs first.
// (See "connected component labelling" or "clustering").
// Note that the code does not find interior (nested) contours.

Point2d firstPixel;
PImage img;
int N=1;

//a class for single coordinate pairs that we will feed into a chain
class Point2d {
  int x, y;
  Point2d (int inx, int iny) {
    x = inx;
    y = iny;
  }
}


ArrayList<ArrayList<Point2d>> chainlist = new ArrayList<ArrayList<Point2d>>();
ArrayList<Point2d>[] chain = (ArrayList<Point2d>[])new ArrayList[5];


//===============================================
void setup() {
  img = loadImage("ex1.png");
  size(img.width, img.height);
  firstPixel = new Point2d(0, 0);
  chain[0] = new ArrayList<Point2d>();

}



//===============================================
void draw() {
  background(255);
  image(img,0,0);

  loadPixels();
  findFirstBlobPixel();
  compute8NeighborChainCode (firstPixel.x, firstPixel.y);

  drawChainCode();
  drawAnnotations();
}



//===============================================
void drawSomeWhiteBlobs() {
  noStroke();
  fill(0);
  ellipse(mouseX, mouseY, 140, 150);
  ellipse(230, 200, 100, 70);
  ellipse(280, 190, 70, 140);
  rect(300, frameCount%height, 50, 50);
}

//===============================================
void findFirstBlobPixel() {
  boolean foundFirst = false;
  for (int y=mouseY; y<height; y++) {
    for (int x=mouseX; x<width; x++) {
    //all pixels in the display window are kept in an array called pixels[]
    //we check the color of the current pixel
      color val = pixels[y*width + x];
      //we check for a black pixel
      if (!foundFirst && brightness(val) < 255) {
        firstPixel.x = x;
        firstPixel.y = y;
        foundFirst = true;
      }
    }
  }
}

//===============================================
/*  Compute the chain code of the object beginning at pixel (i,j).
    Return the code as NN integers in the array C.          */
void compute8NeighborChainCode (int i, int j) {
  int val, n, m, q, r, ii, d, dii;
  int lastdir, jj;
  chain[0].clear();

  // Table given index offset for each of the 8 directions.
  int di[] = {
    0, -1, -1, -1, 0, 1, 1, 1
  };
  int dj[] = {
    1, 1, 0, -1, -1, -1, 0, 1
  };


  val = pixels[j*width+i]; 
  n = 0; /* Initialize for starting pixel */
  q = i;   
  r = j; 
  lastdir = 4;

  do {
    m = 0;
    dii = -1;  
    d = 100;
    for (ii=lastdir+1; ii<lastdir+8; ii++) {     /* Look for next */
      jj = ii%8;
      if (isPixelLocationLegal (di[jj]+q, dj[jj]+r)) {
        if ( pixels[(dj[jj]+r)*width + (di[jj]+q)] == val) {
          dii = jj;
          m = 1;
          break;
        }
      }
    }

    if (m != 0) { /* Found the next pixel ... */
      Point2d P = new Point2d(q, r);
      chain[0].add(P);

      q += di[dii];
      r += dj[dii];
      lastdir = (dii+5)%8;
    }
    else {
      break;    /* NO next pixel */
    }
  }
  while ( (q!=i) || (r!=j) );   /* Stop when next to start pixel */
}

//===============================================
void drawChainCode() {
  noFill();
  strokeWeight(3);
  stroke(255, 0, 0);
  /* beginShape();
  for (int i=0; i<chain.size(); i++) {
    Point2d P = (Point2d)chain.get(i);
    vertex(P.x, P.y);
  }
  endShape(); */

  for (int C=0; C<chainlist.size(); C++) {
      ArrayList<Point2d> currchain = chainlist.get(C);
      beginShape();
      //print all point pairs in that chain
      for (int i=0; i<currchain.size(); i++) {
      Point2d P = (Point2d)currchain.get(i);
      vertex(P.x, P.y);
      }
      endShape();
    }

}

//===============================================
void drawAnnotations() {
  fill(#8BC0FF);
  String heading = "BITMAP-TO-VECTOR BLOB TRACER\n";
  heading       += "This app extracts the contour (red) of the topleft-most blob,\n";
  heading       += "using an 8-neighbor connected chain code.\n";
  heading       += "# Contour points: " + chain[0].size();
  heading       += "# Chains saved: " + chainlist.size();
  text(heading, 15, 20);
}


//===============================================
boolean isPixelLocationLegal (int x, int y) {
  if (x < 0 || x >= width)  return false;
  if (y < 0 || y >= height) return false;
  return true;
}

void keyPressed() {
    if (key == 's'){ 
    println("Saving pointchain in slot "+N);
    chain[N] = new ArrayList<Point2d>();
    println("the chain we're saving is this big: "+chain[0].size());
    chain[N] = chain[0];
    chainlist.add(chain[N]);
    println("A new pointchain "+chain[N].size() + " points long has been added.");
    for (int B=0; B<N; B++){
      println("Pointchain "+B+" is "+chain[B].size() + " points long.");
    }
    N ++;
   println("You now have "+ chainlist.size() +" chains saved.");
    }
    if (key == 'p'){
    //select each chain and print it
    println("Printing chains. You have "+chainlist.size()+".");
    for (int C=0; C<chainlist.size(); C++) {
      println("Chain " +C+ ", which is "+chain[C].size()+" points long, printing.");
        for (int i=0; i<chain[C].size(); i++) {
          Point2d D = (Point2d)chain[C].get(i);
          println(D.x, D.y);
        }
    }
    }
}

Answer 1

我目前无法解决OOP问题，但如果您只想显示白色背景而不是粉红色的图像，那么您可以做的一件事就是简单地应用{{1} } filter()将您的彩色图像转换为二进制图像（黑白）：

THRESHOLD

“等待数据包”崩溃和ArrayList问题

1 个答案: