A value parity combination based scheme for retinal images watermarking

In order to improve the security of images exchanged in telemedicine, we propose in this paper, 2 watermarking schemes for retinal image protection; each scheme will be declined into 2 variants. The integration of the watermark will be performed by combining the parity of the successive values; each variant will represent a different combination. These approaches will be implemented in the three insertion domains: spatial, frequency and multi-resolution domain. For the spatial domain, the watermark will be integrated into the R, G and B values of the image. In the frequency domain, the watermark bits will be substituted to the DCT coefficient’s least significant bit. For the multi-resolution domain insertion, after calculating a DWT, the obtained LL sub-band coefficients will be used for the integration process. After comparing our approaches to the different recent works in the three domains; the obtained results demonstrate that our first proposed approach offers a good imperceptibility for the frequency and spatial domains insertion. However, using 512 × 512 images for our experiments considerably reduces the capacity of our approach in the frequency domain.