Table 3.

A Comparison Between Our Scheme and the Reviewed Schemes

Scheme	Objectives	Methodology			Capabilities			Characteristics
		ROI-based	Embedding technique	Block-based	Reversible	Taper localization	Tamper recovery	Robustness	Hiding capacity	Visual quality
Zain12,13	Authentication	✓	Spatial LSB	×	✓	×	×	Fragile	No Patient’s data are embedded. Only authentication data are embedded	Good
Zain23	Authentication	×	Spatial LSB	16 × 16	×	✓	Average of blocks	Fragile	No Patient’s data are embedded. Only authentication and recovery data are embedded. Hiding capacity = 0.44 bpp	Good
Zain24	Authentication	✓	Spatial LSB	4 × 4, 2 × 4	×	✓	Average of blocks	Fragile	No Patient’s data are embedded. Only authentication and recovery data are embedded	Good
Wu16 (1)	Authentication	×	Frequency DCT	Size is not fixed	✓	✓	Compressed form of each block	Robust (based on modulo 256 addition), but no test results provided by the authors.	No Patient’s data are embedded. Only authentication data are embedded	Good
Wu16 (1)	Authentication	✓	Frequency DCT	Size is not fixed	✓	✓	✓			Good
Chiang19 (1)	Authentication	✓	Modified DE	4 × 4	✓	✓	Average of blocks	Fragile	Low hiding capacity. No Patient’s data can be embedded. Moreover, it cannot be used for all image modalities since embedding is done in smooth blocks only.	Good
Chiang19 (2)		✓			✓	✓	✓	Fragile		Good
Anand18	Data Hiding	✓	Spatial LSB	✓	✓	✓	✓	Fragile	High embedding capacity up to 1 bpp	Good
Nayak21	Data Hiding	✓	Spatial LSB	✓	✓	✓	✓	Fragile	High embedding capacity up to 1 bpp	Good
Giakoimaki6–10	Authentication and Data Hiding	✓	Frequency DWT	×	×	×	×	The results show high robustness against JPEG compression. Not tested against other type of attacks.	For images of size m x n: Total size of patient data that can be embedded (with no ECC) = 21 mn/256 bits.With ECC it will be decreased to forth of that. Hiding capacity is 0.08 bpp without ECC and 0.02 bpp with ECC	Good
Woo22	Authentication and Data Hiding	×	DWT + LSB	×	×	×	×	Although the robustness wasn’t tested, it easy to figure out that the scheme is fragile as it is based on LSB. Only the data hid in the border may survive certain attacks.	Only the border of the image is used for embedding patient’s data. The size of the border is not determined but it quite small. This means low hiding capacity	Very good
Gou15	Authentication and Data Hiding	✓	Spatial + DE	4 × 4	✓	×	×	Fragile	Theoretically, 3 bits can be embedded into a block of 2 × 2, which means 0.75 bpp. However, the authors did not use the scheme for hiding patient’s data. It can be used for data hiding.	Very good
Our scheme	Authentication and Data Hiding	✓	Modified DE + Frequency DWT	16 × 16	Only ROI	✓	Compressed form of ROI	Shows some robustness against cropping and certain level of salt and pepper noise	The overall capacity is in the range 0.46–0.50 bpp	Very good