In this paper a new blind technique using one dimensional Walsh coding to improve the robustness of image watermarking is presented. The algorithm uses 1-D Walsh coding to embed mobile phone digits in color images captured by a still image camera. The new technique inserts the coded binary bits of the phone digits in the discrete cosine transform (DCT) blocks of the green channel of the digital color image. The use of the green channel produced better results compared to the previous DCT algorithms using the Y-Channel. Also, the Walsh coding has improved robustness against JPEG compression, cropping and some filtering attacks.