An Efficient Image Watermarking Method Based on Fast Discrete Cosine Transform Algorithm

Table 2

Validation of the watermarking method, where the watermarked image remains in excellent quality with PSNR ≥ 30 dB and the retrieved watermark with perfect NC = 1.0.

The original image of size 256 × 256 and the watermark of size 64 × 64.
The watermarked image using middle frequency coefficients (6, 11, 12, and 14 in Figure 2) with PSNR = 31.256 dB, and NC = 1.0.