how to hide a binary image within grayscale image using lsb ...pls help me by matlab code

i create a saliency map of a grayscale image.after that i classify that image i.e. image's black color portion value is '0',gray color portion value is '100' and white color portion value is '255'.now i want to hide a binary image by changing the bit position of the classified image's. i.e. changing last two bit of the black color portion and only changing the last bit of the gray color portion and white remain fixed by comparing with the binary image.

[Walter Roberson]

http://www.mathworks.com/matlabcentral/answers/6200-tutorial-how-to-ask-a-question-on-answers-and-get-a-fast-answer

[Walter Roberson]

Is the strategy "insert data in the black portions first, and if there are still more bits that need added, put them in the gray part" ?

[sridip sahoo]

my goal is to watermark in the black region and gray region...do not watermark in the white region...at first check the binary image's bit value...suppose it is '1' in 1st row 1st colom. then check the thresholded image's bit value on 1st row and 1st colom..if it is close or equal to 100 then it should be gray region...and then go to the saliency image's bit value matrix and change the last bit of 1st row and 1st colom...that means convert 100 into binary form and add 1...for '0' it convert to binary that means 00000000 then add 1 on last two bit..that means it becomes 00000011.then the actual bit value becomes '3'....[n.b. I think the bit position of saliency image and thresholded image are same...]

Answer 1

[Image Analyst]

For what it's worth, attached is my LSB watermarking demo. Feel free to adapt it if it doesn't do exactly what you want.