**2.2.3 Overflow/underflow issues**

An overflow/underflow can be occurred during bit embedding if a pixel value of the host image is a little either less than 255 or larger than 0. To overcome the overflow/underflow issues, a pixel-shifting approach can be performed in the spatial domain before data embedment. Namely, if a pixel value *p* in a host image satisfied either *p* <sup>1</sup> or , *p* <sup>2</sup> *p* can be adjusted to a new value by adding to 1 or subtracting from <sup>2</sup> . Both 1 and <sup>2</sup> are two predetermined threshold values.
