Nested Quantization Index Modulation for Reversible Watermarking and Its Application to Healthcare Information Management Systems

Figure 16

The watermarked images (a), the reconstructed images (b), and the extracted watermarks ((c) and (d)) with the quantization steps 𝑞₁=30 and 𝑞₂=30.

(a)

(b)

(c)

(d)