Novel Variants of a Histogram Shift-Based Reversible Watermarking Technique for Medical Images to Improve Hiding Capacity

Table 2

Comparison of the hiding capacity for novel variants with the classical histogram shift technique.

Image	Image size	Hiding capacity in bits (histogram shift)	Block-wise histogram shift in bits (4 × 4)	Block-wise histogram shift in bits (8 × 8)	Block-wise histogram shift in bits (16 × 16)	Embedding in non-ROI in bits
Cover1	900 × 854	44,417	48,164	46,201	45,367	44,494
Cover2	1002 × 1132	36,947	42,258	39,567	38,253	37,103
Cover3	544 × 304	37,651	43,784	41,211	39,499	37,862