java - 在android上实现离散小波变换

Question

我正在编写一个应用程序以在图像上应用离散小波变换，然后将其反转应用该算法的类将在 java 中运行，但是当我尝试将其转换为 android 平台时，图像不会出现我不不知道为什么这里是类和主要 Activity 的代码:

wtc 使用 haar 类:

import android.graphics.Bitmap;

/**
 * @author the-e_000
 */
public class haar {

    private final double w0 = 0.5;
    private final double w1 = -0.5;
    private final double s0 = 0.5;
    private final double s1 = 0.5;

    /// <summary>
    ///   Discrete Haar Wavelet Transform
    /// </summary>
    ///
    public void FWT(double[] data) {
        double[] temp = new double[data.length];

        int h = data.length >> 1;
        for (int i = 0; i < h; i++) {
            int k = (i << 1);
            temp[i] = data[k] * s0 + data[k + 1] * s1;
            temp[i + h] = data[k] * w0 + data[k + 1] * w1;
        }

        for (int i = 0; i < data.length; i++)
            data[i] = temp[i];
    }

    /// <summary>
    ///   Discrete Haar Wavelet 2D Transform
    /// </summary>
    ///
    public void FWT(double[][] data, int iterations) {
        int rows = data.length;
        int cols = data[0].length;
        double[] row = new double[cols];
        double[] col = new double[rows];
        for (int k = 0; k < iterations; k++) {
            for (int i = 0; i < rows; i++) {
                for (int j = 0; j < row.length; j++)
                    row[j] = data[i][j];
                FWT(row);
                for (int j = 0; j < row.length; j++)
                    data[i][j] = row[j];
            }
            for (int j = 0; j < cols; j++) {
                for (int i = 0; i < col.length; i++)
                    col[i] = data[i][j];
                FWT(col);
                for (int i = 0; i < col.length; i++)
                    data[i][j] = col[i];
            }
        }
    }

    /// <summary>
    ///   Inverse Haar Wavelet Transform
    /// </summary>
    ///
    public void IWT(double[] data) {
        double[] temp = new double[data.length];

        int h = data.length >> 1;
        for (int i = 0; i < h; i++) {
            int k = (i << 1);
            temp[k] = (data[i] * s0 + data[i + h] * w0) / w0;
            temp[k + 1] = (data[i] * s1 + data[i + h] * w1) / s0;
        }

        for (int i = 0; i < data.length; i++)
            data[i] = temp[i];
    }

    /// <summary>
    ///   Inverse Haar Wavelet 2D Transform
    /// </summary>
    ///
    public void IWT(double[][] data, int iterations) {
        int rows = data.length;
        int cols = data[0].length;
        double[] col = new double[rows];
        double[] row = new double[cols];
        for (int l = 0; l < iterations; l++) {
            for (int j = 0; j < cols; j++) {
                for (int i = 0; i < row.length; i++)
                    col[i] = data[i][j];
                IWT(col);
                for (int i = 0; i < col.length; i++)
                    data[i][j] = col[i];
            }
            for (int i = 0; i < rows; i++) {
                for (int j = 0; j < row.length; j++)
                    row[j] = data[i][j];
                IWT(row);
                for (int j = 0; j < row.length; j++)
                    data[i][j] = row[j];
            }
        }
    }

    public double Scale(double fromMin, double fromMax, double toMin, double toMax, double x) {
        if (fromMax - fromMin == 0) {
            return 0;
        }
        double value = (toMax - toMin) * (x - fromMin) / (fromMax - fromMin) + toMin;
        if (value > toMax) {
            value = toMax;
        }
        if (value < toMin) {
            value = toMin;
        }
        return value;
    }

    public void ApplyHaarTransform(boolean Forward, Bitmap img) throws Exception {

        int Iterations = 1;
        double[][] Red = new double[img.getWidth()][img.getHeight()];
        double[][] Green = new double[img.getWidth()][img.getHeight()];
        double[][] Blue = new double[img.getWidth()][img.getHeight()];
        int c;
        for (int j = 0; j < img.getHeight(); j++) {
            for (int i = 0; i < img.getWidth(); i++) {
                c = img.getPixel(i, j);
                Red[i][j] = (double) Scale(0, 255, -1, 1, (c >> 16) & 0x000000FF);
                Green[i][j] = (double) Scale(0, 255, -1, 1, (c >> 8) & 0x000000FF);
                Blue[i][j] = (double) Scale(0, 255, -1, 1, (c) & 0x000000FF);
            }
        }
        if (Forward) {
            FWT(Red, Iterations);
            FWT(Green, Iterations);
            FWT(Blue, Iterations);
        } else {
            IWT(Red, Iterations);
            IWT(Green, Iterations);
            IWT(Blue, Iterations);
        }
        for (int j = 0; j < img.getHeight(); j++) {
            for (int i = 0; i < img.getWidth(); i++) {
                int r = (int) Scale(-1, 1, 0, 255, Red[i][j]);// red component 0...255
                int g = (int) Scale(-1, 1, 0, 255, Green[i][j]);// green component 0...255
                int b = (int) Scale(-1, 1, 0, 255, Blue[i][j]);// blue component 0...255
                int col = (r << 16) | (g << 8) | b;
                img.setPixel(i, j, col);
            }
        }
    }
}

主要 Activity :

Bitmap img = BitmapFactory.decodeFile(imgDecodableString);
ImageView imgView = (ImageView) findViewById(R.id.imgView);
// take the image and add the transform
haar trans = new haar();
Bitmap img2 = null;
try {
    trans.ApplyHaarTransform(true, true, img);
} catch(Exception e) {
    Toast.makeText(this,e.getMessage(), Toast.LENGTH_LONG).show();
}
// Set the Image in ImageView after decoding the String
imgView.setImageBitmap(img2);

Answer 1

在您的代码中，您在 imageview 中放置了一个空图像:

Bitmap img2 = null;

在转换你的代码之后

imgView.setImageBitmap(img2);

但是

try {
    trans.ApplyHaarTransform(true, true, img);
} catch(Exception e) {
    Toast.makeText(this,e.getMessage(), Toast.LENGTH_LONG).show();
}

对img2没有影响所以你可以改用你的方法:

public void ApplyHaarTransform(boolean Forward, Bitmap img)

返回图像，现在是

public Bitmap ApplyHaarTransform(boolean Forward, Bitmap img)

在结束它的括号之前添加一行代码:

return img;

现在在您的 try catch 代码中，您的代码将是:

try {
    img2=trans.ApplyHaarTransform(true, true, img);
} catch(Exception e) {
    Toast.makeText(this,e.getMessage(), Toast.LENGTH_LONG).show();
}