A Novel Encryption Frame for Medical Image with Watermark Based on Hyperchaotic System

Table 2

Capacity and PSNR of medical images with size of 256×256 with block size of 16×16.

Images	Im21	Im22	Im23	Im24	Im25	Im26	Im27	Im28
Capacity (bit)	4073	3919	4000	4627	4360	3419	3819	3635
PSNR (dB)	56.78	56.88	56.97	56.65	56.87	56.61	57.58	57.68
ROI blocks number	93	89	89	89	89	74	75	76
Threshold	100	100	100	100	100	100	100	100