An Efficient Image Watermarking Method Based on Discrete Cosine Transform

The security of information transmission is a field of extensive research due to its importance nowadays. Watermarking is one of the methods used to protect the originality of the carrier images/objects. It is also considered to be a method for transmitting certain information and an effective way of tracing information. However, despite efforts to protect the data through watermarking, maintaining the proper quality of both the watermark itself and the carrier image remains a significant challenge. It is therefore essential to develop watermarking methods that are capable of achieving acceptable results. In this study, we proposed a watermarking method based on Discrete Cosine Transform (DCT) that is capable of embedding and extracting the watermark without compromising the quality of the original watermark. The success of this system derives from the strategic application of the JPEG quantization table, specifically the luminance table. The proposed method was able to achieve satisfying results (NC=0.998, and PSNR=41.4099) despite the fact that the image was subjected to JPEG compression.