dwt.java

这是DWT和IDWT的源码. 离散小波的原始程式。

/*
 ****************************************************************************
 *
 *   Transform a grayscale image into a wavelet integer array
 *
 ****************************************************************************
 */
import java.io.*;

public class Dwt {

  public static void main(String[] args) {
    int  level, nrows, ncols;
    int  img[][], source[][], result[][];
    int  i, j, i1, j1, i2, j2, k;
    int  nr, nc, nr2, nc2;

    if (args.length != 5) {
      System.out.println(
        "Usage: Dwt <level> <nrows> <ncols> <img> <out_file>");
      System.exit(0);
    }
    // Command line processing:
    level = Integer.parseInt(args[0]);
    if (level <= 0) {
      System.out.println("Number of levels should be greater than 0.");
      System.exit(0);
    }
    nrows = nr = Integer.parseInt(args[1]);
    ncols = nc = Integer.parseInt(args[2]);
    img = new int[nrows][ncols];
    ArrayIO.readByteArray(args[3], img, nrows, ncols);
    source = new int[nrows][ncols];
    result = new int[nrows][ncols];

    for (i=0; i<nrows; i++)
      for (j=0; j<ncols; j++)
        source[i][j] = img[i][j];

    for (k=1; k<=level; k++, nr/=2, nc/=2) {
      // Horizontal processing:
      nc2 = nc/2;
      for (i=0; i<nr; i++) {
        for (j=0; j<nc; j+=2) {
          j1 = j+1;
          j2 = j/2;
          result[i][j2] = source[i][j] + source[i][j1];
          result[i][nc2+j2] = source[i][j] - source[i][j1];
        }
      }
      // Copy to source:
      for (i=0; i<nr; i++)
        for (j=0; j<nc; j++)
          source[i][j] = result[i][j];

      // Vertical processing:
      nr2 = nr/2;
      for (i=0; i<nr; i+=2) {
        for (j=0; j<nc; j++) {
          i1 = i+1;
          i2 = i/2;
          result[i2][j] = source[i][j] + source[i1][j];
          result[nr2+i2][j] = source[i][j] - source[i1][j];
        }
      }
      // Copy to source:
      for (i=0; i<nr; i++)
        for (j=0; j<nc; j++)
          source[i][j] = result[i][j];
    }
    ArrayIO.writeIntArray(args[4], result, nrows, ncols);
  }

}