JIP_V1_N3_RP2 N. Harathi V. Meenakshi C.H. Suneetha Journal on Image Processing 2349-6827 1 3 23 32 DCT, DWT, DTT, PSNR, Image watermarking The proliferation of digitized media due to the rapid growth of networked multimedia systems has created an urgent need for copyright enforcement technologies that can protect copyright. In this paper implementation of three different watermarking algorithms in the frequency domain is presented. The first algorithm is based on the Discrete Cosine Transform (DCT), the second one is based on the Discrete Wavelet Transform (DWT) and the third algorithm is based on the Discrete Tchebichef Transform (DTT).Embedding the watermark is done by modifying the coefficients of the middle frequency band so that the visibility of the image and diagnosis capability will not be affected. All schemes are tested using images and the simulation results are compared and the comparison shows the best scheme. July - September 2014 Copyright © 2014 i-manager publications. All rights reserved. i-manager Publications http://www.imanagerpublications.com/Article.aspx?ArticleId=2961