jpegencoder.java

基于JPEG图像的数字密写方法 F5算法的JAVA程序

		    if (coeff[shuffledIndex] == 0) continue; // skip zeroes
		    _examined++;
		    if (coeff[shuffledIndex] > 0) {
			if ((coeff[shuffledIndex]&1) != nextBitToEmbed) {
			    coeff[shuffledIndex]--; // decrease absolute value
			    _changed++;
			}
		    } else {
			if ((coeff[shuffledIndex]&1) == nextBitToEmbed) {
			    coeff[shuffledIndex]++; // decrease absolute value
			    _changed++;
			}
		    }
		    if (coeff[shuffledIndex] != 0) {
			// The coefficient is still nonzero. We
			// successfully embedded "nextBitToEmbed".
			// We will read a new bit to embed now.
			if (availableBitsToEmbed==0) {
			    // If the byte of embedded text is
			    // empty, we will get a new one.
			    try {
				if (embeddedData.available()==0) break;
				byteToEmbed=embeddedData.read();
				byteToEmbed ^= random.getNextByte();
			    } catch (Exception e) {
				e.printStackTrace();
				break;
			    }
			    availableBitsToEmbed=8;
			}
			nextBitToEmbed = byteToEmbed & 1;
			byteToEmbed >>= 1;
			availableBitsToEmbed--;
			_embedded++;
		    } else _thrown++;
		}
	    }
if (_examined > 0)
    System.out.println(_examined+" coefficients examined");
System.out.println(_changed+" coefficients changed (efficiency: "
	    +(_embedded/_changed)+"."+(((_embedded*10)/_changed)%10)
	    +" bits per change)");
System.out.println(_thrown+" coefficients thrown (zeroed)");
System.out.println(_embedded+" bits ("+_embedded/8+" bytes) embedded");
	}
System.out.println("Starting Huffman Encoding.");
	// Do the Huffman Encoding now.
	shuffledIndex=0;
        for (r = 0; r < MinBlockHeight; r++) {
           for (c = 0; c < MinBlockWidth; c++) {
              for (comp = 0; comp < JpegObj.NumberOfComponents; comp++) {
                 for(i = 0; i < JpegObj.VsampFactor[comp]; i++) {
		    for(j = 0; j < JpegObj.HsampFactor[comp]; j++) {
			System.arraycopy(coeff, shuffledIndex, dctArray3, 0, 64);
			Huf.HuffmanBlockEncoder(outStream, dctArray3,
			    lastDCvalue[comp], JpegObj.DCtableNumber[comp],
			    JpegObj.ACtableNumber[comp]);
			lastDCvalue[comp] = dctArray3[0];
			shuffledIndex += 64;
                    }
                 }
              }
           }
        }

        Huf.flushBuffer(outStream);
    }

    public void WriteEOI(BufferedOutputStream out) {
        byte[] EOI = {(byte) 0xFF, (byte) 0xD9};
        WriteMarker(EOI, out);
    }

    public void WriteHeaders(BufferedOutputStream out) {
        int i, j, index, offset, length;
        int tempArray[];

// the SOI marker
        byte[] SOI = {(byte) 0xFF, (byte) 0xD8};
        WriteMarker(SOI, out);

// The order of the following headers is quiet inconsequential.
// the JFIF header
        byte JFIF[] = new byte[18];
        JFIF[0] = (byte) 0xff;	// app0 marker
        JFIF[1] = (byte) 0xe0;
        JFIF[2] = (byte) 0x00;	// length
        JFIF[3] = (byte) 0x10;
        JFIF[4] = (byte) 0x4a;	// "JFIF"
        JFIF[5] = (byte) 0x46;
        JFIF[6] = (byte) 0x49;
        JFIF[7] = (byte) 0x46;
        JFIF[8] = (byte) 0x00;
        JFIF[9] = (byte) 0x01;	// 1.01
        JFIF[10] = (byte) 0x01;
        JFIF[11] = (byte) 0x00;
        JFIF[12] = (byte) 0x00;
        JFIF[13] = (byte) 0x01;
        JFIF[14] = (byte) 0x00;
        JFIF[15] = (byte) 0x01;
        JFIF[16] = (byte) 0x00;
        JFIF[17] = (byte) 0x00;

        if (JpegObj.getComment().equals("JPEG Encoder Copyright 1998, James R. Weeks and BioElectroMech.  "))
		JFIF[10] = (byte) 0x00;	// 1.00
        WriteArray(JFIF, out);

// Comment Header
        String comment = new String();
        comment = JpegObj.getComment();
        length = comment.length();
	if (length != 0) {
		byte COM[] = new byte[length + 4];
		COM[0] = (byte) 0xFF;
		COM[1] = (byte) 0xFE;
		COM[2] = (byte) ((length >> 8) & 0xFF);
		COM[3] = (byte) (length & 0xFF);
		java.lang.System.arraycopy(JpegObj.Comment.getBytes(), 0, COM, 4, JpegObj.Comment.length());
		WriteArray(COM, out);
	}

// The DQT header
// 0 is the luminance index and 1 is the chrominance index
        byte DQT[] = new byte[134];
        DQT[0] = (byte) 0xFF;
        DQT[1] = (byte) 0xDB;
        DQT[2] = (byte) 0x00;
        DQT[3] = (byte) 0x84;
        offset = 4;
        for (i = 0; i < 2; i++) {
                DQT[offset++] = (byte) ((0 << 4) + i);
                tempArray = (int[]) dct.quantum[i];
                for (j = 0; j < 64; j++) {
                        DQT[offset++] = (byte) tempArray[jpegNaturalOrder[j]];
                }
        }
        WriteArray(DQT, out);

// Start of Frame Header
        byte SOF[] = new byte[19];
        SOF[0] = (byte) 0xFF;
        SOF[1] = (byte) 0xC0;
        SOF[2] = (byte) 0x00;
        SOF[3] = (byte) 17;
        SOF[4] = (byte) JpegObj.Precision;
        SOF[5] = (byte) ((JpegObj.imageHeight >> 8) & 0xFF);
        SOF[6] = (byte) ((JpegObj.imageHeight) & 0xFF);
        SOF[7] = (byte) ((JpegObj.imageWidth >> 8) & 0xFF);
        SOF[8] = (byte) ((JpegObj.imageWidth) & 0xFF);
        SOF[9] = (byte) JpegObj.NumberOfComponents;
        index = 10;
        for (i = 0; i < SOF[9]; i++) {
                SOF[index++] = (byte) JpegObj.CompID[i];
                SOF[index++] = (byte) ((JpegObj.HsampFactor[i] << 4) + JpegObj.VsampFactor[i]);
                SOF[index++] = (byte) JpegObj.QtableNumber[i];
        }
        WriteArray(SOF, out);

// The DHT Header
        byte DHT1[], DHT2[], DHT3[], DHT4[];
        int bytes, temp, oldindex, intermediateindex;
        length = 2;
        index = 4;
        oldindex = 4;
        DHT1 = new byte[17];
        DHT4 = new byte[4];
        DHT4[0] = (byte) 0xFF;
        DHT4[1] = (byte) 0xC4;
        for (i = 0; i < 4; i++ ) {
                bytes = 0;
                DHT1[index++ - oldindex] = (byte) ((int[]) Huf.bits.elementAt(i))[0];
                for (j = 1; j < 17; j++) {
                        temp = ((int[]) Huf.bits.elementAt(i))[j];
                        DHT1[index++ - oldindex] =(byte) temp;
                        bytes += temp;
                }
                intermediateindex = index;
                DHT2 = new byte[bytes];
                for (j = 0; j < bytes; j++) {
                        DHT2[index++ - intermediateindex] = (byte) ((int[]) Huf.val.elementAt(i))[j];
                }
                DHT3 = new byte[index];
                java.lang.System.arraycopy(DHT4, 0, DHT3, 0, oldindex);
                java.lang.System.arraycopy(DHT1, 0, DHT3, oldindex, 17);
                java.lang.System.arraycopy(DHT2, 0, DHT3, oldindex + 17, bytes);
                DHT4 = DHT3;
                oldindex = index;
        }
        DHT4[2] = (byte) (((index - 2) >> 8)& 0xFF);
        DHT4[3] = (byte) ((index -2) & 0xFF);
        WriteArray(DHT4, out);


// Start of Scan Header
        byte SOS[] = new byte[14];
        SOS[0] = (byte) 0xFF;
        SOS[1] = (byte) 0xDA;
        SOS[2] = (byte) 0x00;
        SOS[3] = (byte) 12;
        SOS[4] = (byte) JpegObj.NumberOfComponents;
        index = 5;
        for (i = 0; i < SOS[4]; i++) {
                SOS[index++] = (byte) JpegObj.CompID[i];
                SOS[index++] = (byte) ((JpegObj.DCtableNumber[i] << 4) + JpegObj.ACtableNumber[i]);
        }
        SOS[index++] = (byte) JpegObj.Ss;
        SOS[index++] = (byte) JpegObj.Se;
        SOS[index++] = (byte) ((JpegObj.Ah << 4) + JpegObj.Al);
        WriteArray(SOS, out);

    }

    void WriteMarker(byte[] data, BufferedOutputStream out) {
        try {
                out.write(data, 0, 2);
        } catch (IOException e) {
                System.out.println("IO Error: " + e.getMessage());
        }
    }
        
    void WriteArray(byte[] data, BufferedOutputStream out) {
        int i, length;
        try {
                length = (((int) (data[2] & 0xFF)) << 8) + (int) (data[3] & 0xFF) + 2;
                out.write(data, 0, length);
        } catch (IOException e) {
                System.out.println("IO Error: " + e.getMessage());
        }
    }
}

// This class incorporates quality scaling as implemented in the JPEG-6a
// library.

 /*
 * DCT - A Java implementation of the Discreet Cosine Transform
 */

class DCT
{
    /**
     * DCT Block Size - default 8
     */
    public int N        = 8;

    /**
     * Image Quality (0-100) - default 80 (good image / good compression)
     */
    public int QUALITY = 80;

    public Object quantum[] = new Object[2];
    public Object Divisors[] = new Object[2];

    /**
     * Quantitization Matrix for luminace.
     */
    public int quantum_luminance[]     = new int[N*N];
    public double DivisorsLuminance[] = new double[N*N];

    /**
     * Quantitization Matrix for chrominance.
     */
    public int quantum_chrominance[]     = new int[N*N];
    public double DivisorsChrominance[] = new double[N*N];

    /**
     * Constructs a new DCT object. Initializes the cosine transform matrix
     * these are used when computing the DCT and it's inverse. This also
     * initializes the run length counters and the ZigZag sequence. Note that
     * the image quality can be worse than 25 however the image will be
     * extemely pixelated, usually to a block size of N.
     *
     * @param QUALITY The quality of the image (0 worst - 100 best)
     *
     */
    public DCT(int QUALITY)
    {
        initMatrix(QUALITY);
    }
                        

    /*
     * This method sets up the quantization matrix for luminance and
     * chrominance using the Quality parameter.
     */
    private void initMatrix(int quality)
    {
        double[] AANscaleFactor = { 1.0, 1.387039845, 1.306562965, 1.175875602,
                                    1.0, 0.785694958, 0.541196100, 0.275899379};
        int i;
        int j;
        int index;
        int Quality;
        int temp;

// converting quality setting to that specified in the jpeg_quality_scaling
// method in the IJG Jpeg-6a C libraries

        Quality = quality;
        if (Quality <= 0)
                Quality = 1;
        if (Quality > 100)
                Quality = 100;
        if (Quality < 50)
                Quality = 5000 / Quality;
        else
                Quality = 200 - Quality * 2;

// Creating the luminance matrix

        quantum_luminance[0]=16;
        quantum_luminance[1]=11;
        quantum_luminance[2]=10;
        quantum_luminance[3]=16;
        quantum_luminance[4]=24;
        quantum_luminance[5]=40;
        quantum_luminance[6]=51;
        quantum_luminance[7]=61;
        quantum_luminance[8]=12;
        quantum_luminance[9]=12;
        quantum_luminance[10]=14;
        quantum_luminance[11]=19;
        quantum_luminance[12]=26;
        quantum_luminance[13]=58;
        quantum_luminance[14]=60;
        quantum_luminance[15]=55;
        quantum_luminance[16]=14;
        quantum_luminance[17]=13;
        quantum_luminance[18]=16;
        quantum_luminance[19]=24;
        quantum_luminance[20]=40;
        quantum_luminance[21]=57;
        quantum_luminance[22]=69;
        quantum_luminance[23]=56;
        quantum_luminance[24]=14;
        quantum_luminance[25]=17;
        quantum_luminance[26]=22;
        quantum_luminance[27]=29;
        quantum_luminance[28]=51;
        quantum_luminance[29]=87;
        quantum_luminance[30]=80;
        quantum_luminance[31]=62;
        quantum_luminance[32]=18;
        quantum_luminance[33]=22;
        quantum_luminance[34]=37;
        quantum_luminance[35]=56;
        quantum_luminance[36]=68;
        quantum_luminance[37]=109;
        quantum_luminance[38]=103;
        quantum_luminance[39]=77;
        quantum_luminance[40]=24;
        quantum_luminance[41]=35;
        quantum_luminance[42]=55;
        quantum_luminance[43]=64;
        quantum_luminance[44]=81;
        quantum_luminance[45]=104;
        quantum_luminance[46]=113;
        quantum_luminance[47]=92;
        quantum_luminance[48]=49;
        quantum_luminance[49]=64;
        quantum_luminance[50]=78;
        quantum_luminance[51]=87;
        quantum_luminance[52]=103;
        quantum_luminance[53]=121;
        quantum_luminance[54]=120;
        quantum_luminance[55]=101;
        quantum_luminance[56]=72;
        quantum_luminance[57]=92;
        quantum_luminance[58]=95;
        quantum_luminance[59]=98;
        quantum_luminance[60]=112;
        quantum_luminance[61]=100;
        quantum_luminance[62]=103;
        quantum_luminance[63]=99;

        for (j = 0; j < 64; j++)
        {
                temp = (quantum_luminance[j] * Quality + 50) / 100;
                if ( temp <= 0) temp = 1;
                if (temp > 255) temp = 255;
                quantum_luminance[j] = temp;
        }
        index = 0;
        for (i = 0; i < 8; i++) {
                for (j = 0; j < 8; j++) {
// The divisors for the LL&M method (the slow integer method used in
// jpeg 6a library).  This method is currently (04/04/98) incompletely
// implemented.
//                        DivisorsLuminance[index] = ((double) quantum_luminance[index]) << 3;
// The divisors for the AAN method (the float method used in jpeg 6a library.
                        DivisorsLuminance[index] = (double) ((double)1.0/((double) quantum_luminance[index] * AANscaleFactor[i] * AANscaleFactor[j] * (double) 8.0));
                        index++;
                }
        }


// Creating the chrominance matrix

        quantum_chrominance[0]=17;
        quantum_chrominance[1]=18;
        quantum_chrominance[2]=24;
        quantum_chrominance[3]=47;
        quantum_chrominance[4]=99;
        quantum_chrominance[5]=99;
        quantum_chrominance[6]=99;
        quantum_chrominance[7]=99;
        quantum_chrominance[8]=18;
        quantum_chrominance[9]=21;
        quantum_chrominance[10]=26;
        quantum_chrominance[11]=66;
        quantum_chrominance[12]=99;
        quantum_chrominance[13]=99;
        quantum_chrominance[14]=99;
        quantum_chrominance[15]=99;
        quantum_chrominance[16]=24;
        quantum_chrominance[17]=26;
        quantum_chrominance[18]=56;
        quantum_chrominance[19]=99;
        quantum_chrominance[20]=99;
        quantum_chrominance[21]=99;
        quantum_chrominance[22]=99;
        quantum_chrominance[23]=99;
        quantum_chrominance[24]=47;
        quantum_chrominance[25]=66;
        quantum_chrominance[26]=99;
        quantum_chrominance[27]=99;
        quantum_chrominance[28]=99;
        quantum_chrominance[29]=99;
        quantum_chrominance[30]=99;
        quantum_chrominance[31]=99;
        quantum_chrominance[32]=99;
        quantum_chrominance[33]=99;
        quantum_chrominance[34]=99;
        quantum_chrominance[35]=99;
        quantum_chrominance[36]=99;