java - 无法提取隐写术中的文本

Question

我有一个代码，可以使用此处的代码在 C# 中使用速记将字符串值放在图像上

http://www.codeproject.com/Tips/635715/Steganography-Simple-Implementation-in-Csharp

现在我必须在 Android 端提取字符串。这是我用于文本提取的 Android 端代码

   private String extractText(Bitmap bmp) {
        // TODO Auto-generated method stub
        int colorUnitIndex = 0;
        int charValue = 0;

        // holds the text that will be extracted from the image
        String extractedText ="";

        for(int w=0;w<bmp.getHeight();w++)
        {
            for(int h=0;h<bmp.getWidth();h++)
            {
                int color=bmp.getPixel(h, w);
                green=Color.green(color);
                blue=Color.blue(color);
                red=Color.red(color);

                bred=(byte)red;
                bgreen=(byte)green;
                bblue=(byte)blue;

                // for each pixel, pass through its elements (RGB)
                for (int n = 0; n < 3; n++)
                {
                    switch (colorUnitIndex % 3)
                    {
                        case 0:
                            {
                                // get the LSB from the pixel element (will be pixel.R % 2)
                                // then add one bit to the right of the current character
                                // this can be done by (charValue = charValue * 2)
                                // replace the added bit (which value is by default 0) with
                                // the LSB of the pixel element, simply by addition
                                charValue = charValue * 2 + bred % 2;
                            } break;
                        case 1:
                            {
                                charValue = charValue * 2 + bgreen % 2;
                            } break;
                        case 2:
                            {
                                charValue = charValue * 2 + bblue % 2;
                            } break;
                    }

                    colorUnitIndex++;

                    // if 8 bits has been added, then add the current character to the result text
                    if (colorUnitIndex % 8 == 0)
                    {
                        // reverse? of course, since each time the process happens on the right (for simplicity)
                        charValue = reverseBits(charValue);

                        // can only be 0 if it is the stop character (the 8 zeros)
                        if (charValue == 0)
                        {
                            return extractedText;
                        }

                        // convert the character value from int to char
                        char c = (char)charValue;

                        // add the current character to the result text
                        extractedText += String.valueOf(c);
                    }
                }

            }

        }
        return extractedText;


    }

    private int reverseBits(int n) {
        // TODO Auto-generated method stub


         int result = 0;

            for (int i = 0; i < 8; i++)
            {
                result = result * 2 + n % 2;

                n /= 2;
            }

            return result;
    }

};

但我在 Android 端没有得到正确的字符串。不知道是什么问题。任何人都可以帮忙吗？提前致谢。

Answer 1

终于找到解决办法了只需在每个位的循环上使用此代码，我就可以提取文本。

               result[b] = (byte)((result[b] << 1) | (buff[offset] & 1));

谢谢大家。