Image quality monitoring using spread spectrum watermarking

An improved blind image quality assessment scheme that is based on the Watson´s just noticeable difference (JND) modulated spread spectrum watermarking, is proposed. For the purpose of quality monitoring, a watermark is embedded into the original image. The image quality is estimated based on the detected watermark at the receiver side. In terms of the peak signal-to-noise ratio (PSNR), the proposed method is shown to be more robust and less perceptible than simple spread spectrum watermarking. This is due to several factors: an optimum detector is used for watermark detection, the watermark is appropriately selected from a set and the detector parameter is adjusted accordingly to closely yield an empirical ideal quality curve. The proposed method was tested by finding the quality estimates of different images compressed with different quality factors. The results indicate that the method can accurately estimate the quality of the received images based on the detected watermark power.