  Reversible data hiding continues to attract significant attention in recent
years. In particular, an increasing number of authors focus on the higher
significant bit (HSB) plane of an image which can yield more redundant space.
On the other hand, the lower significant bit planes are often ignored for
embedding in existing schemes due to their harm to the embedding rate. This
paper proposes an efficient reversible data hiding scheme via a double-peak
two-layer embedding (DTLE) strategy with prediction error expansion. The higher
six-bit planes of the image are assigned as the HSB plane, and double
prediction error peaks are applied in either embedding layer. This makes fuller
use of the redundancy space of images compared with the one error peak
strategy. Moreover, we carry out the median-edge detector pre-processing for
complex images to reduce the size of the auxiliary information. A series of
experimental results show that our DTLE approach achieves up to 83% higher
embedding rate on real-world datasets while guaranteeing better image quality.
