圖檔銳化

/**
 * 圖檔銳化（拉普拉斯變換）
 * @param bmp
 * @return
 */
private Bitmap sharpenImageAmeliorate(Bitmap bmp)
{
    long start = System.currentTimeMillis();
    int[] laplacian = new int[] { -1, -1, -1, -1, 9, -1, -1, -1, -1 };

    int width = bmp.getWidth();
    int height = bmp.getHeight();
    Bitmap bitmap = Bitmap.createBitmap(width, height, Bitmap.Config.RGB_565);

    int pixR = 0;
    int pixG = 0;
    int pixB = 0;

    int pixColor = 0;

    int newR = 0;
    int newG = 0;
    int newB = 0;

    int idx = 0;
    float alpha = 0.3F;
    int[] pixels = new int[width * height];
    bmp.getPixels(pixels, 0, width, 0, 0, width, height);
    for (int i = 1, length = height - 1; i < length; i++)
    {
        for (int k = 1, len = width - 1; k < len; k++)
        {
            idx = 0;
            for (int m = -1; m <= 1; m++)
            {
                for (int n = -1; n <= 1; n++)
                {
                    pixColor = pixels[(i + n) * width + k + m];
                    pixR = Color.red(pixColor);
                    pixG = Color.green(pixColor);
                    pixB = Color.blue(pixColor);

                    newR = newR + (int) (pixR * laplacian[idx] * alpha);
                    newG = newG + (int) (pixG * laplacian[idx] * alpha);
                    newB = newB + (int) (pixB * laplacian[idx] * alpha);
                    idx++;
                }
            }

            newR = Math.min(255, Math.max(0, newR));
            newG = Math.min(255, Math.max(0, newG));
            newB = Math.min(255, Math.max(0, newB));

            pixels[i * width + k] = Color.argb(255, newR, newG, newB);
            newR = 0;
            newG = 0;
            newB = 0;
        }
    }

    bitmap.setPixels(pixels, 0, width, 0, 0, width, height);
    long end = System.currentTimeMillis();
    return bitmap;
}