A Novel Reversible Data Hiding Method with Contrast Enhancement Based on Order and Brightness Preservation

With the widespread adoption of the Internet and smart devices, protecting digital information during transmission has become increasingly important. Reversible Data Hiding (RDH) enables secret data to be embedded into digital images while allowing both the hidden data and the original image to be recovered losslessly. To improve image quality, Contrast Enhancement (CE) techniques have been integrated into RDH methods to enhance image details and features. However, existing CE-RDH methods often suffer from excessive enhancement and visual distortion at high embedding rates, resulting in unnatural brightness variation and degradation of visual quality. Therefore, this study proposes a novel reversible data hiding method with contrast enhancement based on order and brightness preservation. An adaptive histogram bin merging strategy and histogram stretching technique are employed during preprocessing to improve embedding capacity and contrast enhancement performance while preserving pixel order and reducing intensity mismatch artifacts. In the data embedding stage, a brightness-preserving embedding mechanism is adopted to adaptively adjust the embedding direction according to image brightness, preventing over-enhancement and maintaining visual consistency. Experimental results on the USC-SIPI and Kodak datasets demonstrate that the proposed method increases embedding capacity by 5–40% while maintaining Relative Mean Brightness Error (RMBE) above 0.99, Peak Signal-to-Noise Ratio (PSNR) above 24.2 dB, and Structural Similarity Index Measure (SSIM) above 0.882, outperforming existing CE-RDH methods in brightness preservation, visual quality, and contrast enhancement performance.