Watermarking-Based Blind QoS Assessment for Wireless Image Communication

This paper presents a novel scheme to blindly estimate the quality of an image communication link by means of an unconventional use of digital watermarking. The watermarking technique is usually employed for digital media copyright protection and authenticity verification. However, watermarking is here adopted as a method to provide a blind assessment of the quality of service (QoS) in wireless image communication. First, a compressed-domain watermarking scheme is proposed. Each 8×8 block in a JPEG compressed image is first processed by entropy decoding, and then the parity of the number of non-zero alternating current (AC) coefficients in each quantized discrete cosine transform (DCT) block is modified to embed the watermark. Second, the performances of the proposed watermarking scheme have been tested. Finally, the proposed watermarking scheme is applied to estimate the QoS of an image communication link based on the assessment factor which is associated with the errors between the extracted watermark and the original. Experimental results show the proposed scheme can evaluate the QoS of wireless image communication channels exactly without increasing the bit rate transmission. Moreover, the quality of the carrier image has not been affected. 