我正在编写一个应用程序来使用LSB隐藏另一个图像中的图像。编码返回的图像与隐藏的图像不同，现在搜索问题已经有一段时间了，我认为在我的代码中我变得非常盲目。
如果有人可以看一看并给我一个提示，我会非常感激。下面的重要代码和整个项目（如果有人想测试它）在链接下：https://github.com/miassma/Steganography.git
public class SteganographyOperationsUtil {
/*checking if the image to hide can fit the hiding image
it returns the range of shades of gray that can be kept in the hiding image*/
public static int checkImages(ImageModel hiding, ImageModel toHide, ImageModel copyOfToHide){
int hidingSize = hiding.getWidth() * hiding.getHeight();
int toHideSize = toHide.getWidth() * toHide.getHeight();
int header = 40;
int value = 8;
while((toHideSize * value + header) > hidingSize){ //if doesnt fit, reducing one range, checking again
value--;
if(value==0){
break;
}
}
if(value == 0) return -1;
if(value<8) posterize(copyOfToHide, (int)pow(2, value)); //run the posterisation if needed
return (int)pow(2, value);
}
/* preparing the hiding image
we need zero on each LSB
*/
public static void prepareHidingImage(ImageModel imgModel){
for (int x = 0; x < imgModel.getWidth(); ++x) {
for (int y = 0; y < imgModel.getHeight(); ++y) {
int color = imgModel.getImage().getRaster().getPixel(x, y, new int[1])[0];
int temp = 254;
int newColor = color & temp;
int[] newColorPixel = {newColor};
imgModel.getImage().getRaster().setPixel(x, y, newColorPixel);
}
}
imgModel.imageChanged();
}
//fullfill by leading zeros with the lenght of the option
public static String fillString(String toFill, int option){
String zero = "0";
if (toFill.length() < option){
int temp = option - toFill.length();
do{
toFill = zero.concat(toFill);
}while(--temp >0);
}
return toFill;
}
/* fullfill the string to get the color matching the posterisation range
for example 1 will be 11111111 (2 ranges of gray)
101 will become 10110110 (3 ranges of gray)
1011 will become 10111011 (4 ranges of gray)
*/
public static String complete(String toComplete){
while (toComplete.length() < 9){
toComplete = toComplete+toComplete;
}
toComplete = toComplete.substring(0, 8);
return toComplete;
}
//hiding Image
public static void hidingOperation(ImageModel hiding, ImageModel toHide, int value){
prepareHidingImage(hiding);
String posterisation = Integer.toString(value-1, 2);
String hiddenWidth = Integer.toString(toHide.getWidth(), 2);
String hiddenHeight = Integer.toString(toHide.getHeight(), 2);
hiddenWidth = fillString(hiddenWidth, 16);
hiddenHeight = fillString(hiddenHeight, 16);
posterisation = fillString(posterisation, 8);
String header = hiddenWidth;
header = header.concat(hiddenHeight);
header = header.concat(posterisation);
int newColor;
int temp = 0;
int temp2 = 0;
int bitsToCheck = (int)logb(value, 2); //how many bits of each pixel we have to hide for given postarisation
int zero = 0;
int one = 1;
int i = 0;
int j = 0;
String colorOfToHideBinary = "";
outerLoop:
for (int x = 0; x < hiding.getWidth(); ++x) {
for (int y = 0; y < hiding.getHeight(); ++y) {
int color = hiding.getImage().getRaster().getPixel(x, y, new int[1])[0];
//filling header
if(temp < header.length()){
if(header.charAt(temp)== '0'){
newColor = color | zero;
}else{ newColor = color | one;
}temp++;
//hiding image
}else{
/*
getting the value of the next pixel of the image to hide, only if temp ==0,
what means that it is the first pixel or each needed bits by the posterisation range
has been already checked
*/
if(temp2 == 0){
int colorOfToHide = toHide.getImage().getRaster().getPixel(i, j, new int[1]) [0];
colorOfToHideBinary = Integer.toString(colorOfToHide, 2);
colorOfToHideBinary = fillString(colorOfToHideBinary, 8);
}
//i check each value of the color in binary, but only as much as needed by the posterisation range
if (colorOfToHideBinary.charAt(temp2) == '0'){
newColor = color | zero;
}else { newColor = color | one;}
temp2++;
if (temp2 == bitsToCheck){
temp2 = 0;
j++;
if(j == toHide.getHeight()){
j = 0;
i++;
}
}
}
int[] newColorPixel = {newColor};
hiding.getImage().getRaster().setPixel(x, y, newColorPixel);
if(i == toHide.getWidth()){
break outerLoop;
}
}
}
hiding.imageChanged();
}
//decrypting image
public static ImageModel encodingOperation(ImageModel imgModel){
int i = 0;
int j = 0;
String widthB = "";
String heightB = "";
String posterisationB = "";
int temp = 0;
int one = 1;
/* loop for taking values from the header, seems to work pretty fine */
outerLoop:
for (int x = 0; x < imgModel.getWidth(); ++x) {
for (int y = 0; y < imgModel.getHeight(); ++y) {
int color = imgModel.getImage().getRaster().getPixel(x, y, new int[1])[0];
if(temp<16){
if ((color & one) == one) widthB = widthB.concat("1");
else widthB = widthB.concat("0");
}else if(temp < 32){
if ((color & one) == one) heightB = heightB.concat("1");
else heightB = heightB.concat("0");
}else if(temp <40){
if ((color & one) == one) posterisationB = posterisationB.concat("1");
else posterisationB = posterisationB.concat("0");
}else{
break outerLoop;
}temp++; j++;
}i++;
}
int width = Integer.parseInt(widthB, 2);
int height = Integer.parseInt(heightB, 2);
int posterisation = Integer.parseInt(posterisationB, 2);
int bitsToCheck = (int)logb(posterisation+1, 2);
int temp2 = 0;
String colorInBinary = "";
//preparing the canvas for the encoded image, width and height from the header
ImageModel encryptedImage = ImageModel.fromHidden(width, height);
int a = 0;
int b = 0;
/* encoding the image
starting after the point after the header, saved in the variables i,j
*/
outerLoop:
for (int x = i; x < imgModel.getWidth(); ++x) {
for (int y = j; y < imgModel.getHeight(); ++y) {
int color = imgModel.getImage().getRaster().getPixel(x, y, new int[1])[0];
/* pixel by pixel reading color of the hidden image
temp2 checks, where to stop - how many LSB of the hiding image keeps information bout one pixel of the hidden img
*/
if ((color & one) == one) colorInBinary = colorInBinary.concat("1");
else colorInBinary= colorInBinary.concat("0");
temp2++;
if (temp2 == bitsToCheck){
temp2 = 0;
//fullfilling the color to the right by the given posterisation range
colorInBinary = complete(colorInBinary);
int newColor = Integer.parseInt(colorInBinary, 2);
colorInBinary = "";
int[] newColorPixel = {newColor};
encryptedImage.getImage().getRaster().setPixel(a, b, newColorPixel);
b++;
if(b == height){
a++;
b=0;
}if (a == width){
break outerLoop;
}
}
}
}
return encryptedImage;
}
public static double logb( double a, double b ){
return Math.log(a) / Math.log(b);
}
public static void posterize(ImageModel imgModel, int value) {
int[] lut = new int[256];
float param1 = 255.0f / (value - 1);
float param2 = 256.0f / (value);
for (int i = 0; i < 256; ++i) {
lut[i] = (int)((int)(i / param2) * param1);
}
useLUT(imgModel, lut);
}
public static void useLUT(ImageModel imgModel, int[] lut) {
for (int x = 0; x < imgModel.getWidth(); ++x) {
for (int y = 0; y < imgModel.getHeight(); ++y) {
int color = imgModel.getImage().getRaster().getPixel(x, y, new int[1])[0];
int[] newColorPixel = {lut[color]};
imgModel.getImage().getRaster().setPixel(x, y, newColorPixel);
}
}
imgModel.imageChanged();
}