IOSR Journal of Electronics and Communication Engineering (IOSR-JECE) e-ISSN: 2278-2834,p- ISSN: 2278-8735.Volume 11, Issue 2, Ver. III (Mar-Apr .2016), PP 48-51 www.iosrjournals.org DOI: 10.9790/2834-1102034851 www.iosrjournals.org 48 | Page Different Methods of Mosaic Image Creation for Secure Data Transmission Gita Kumari, Dr. Shilpi Sharma PG Scholar, Dept. of ECE Bhopal Institute of Technology Bhopal, India Professor, Dept. of ECE Bhopal Institute of Technology Bhopal, India Abstract: Nowadays multimedia data from different sources are required to transmit through the web for very pertinent applications. This multimedia data may contain confidential data so they must be protected during transmission to avoid leakage. Multimedia data includes high percentage of images. The protection of this multimedia data is done by visual cryptography. There are so many different skilful techniques design to conduct for protection of this confidential image data from unauthorized access. One technique in visual cryptography is mosaic image creation, in which is a picture that has been divided into equal sized rectangular tiled sections, each of which is replaced with another photograph that matches the target photo. In this paper we study different method of creating mosaic image for secure image transmission. Keywords: Visual cryptography, mosaic images, color transformation, image encryption, mosaic image, secure image transmission. I. Introduction Visual cryptography technique allows the visual information to be encrypted in such a way that their decryption can be performed by human visual system. Visual cryptography was mainly introduced for the problem of secret sharing. Secret sharing is one of the major problems to be considered in cryptography. Secret sharing is one type of key establishment protocols [1]-[2]. Visual cryptography is introduced by first in 1994 Noar and Shamir [3]. They proposed visual secret sharing scheme, where an image is divided into n shares so that only someone with all n shares could decrypt the image, while someone with any n-1 shares can retrieve no information about the original image. Each share is printed on a different transparency and decryption is performed by overlaying the shares when all n shares are overlaid, the original image gets visible [4]. The main objective is to communicate securely in such a way that the secret message is not visible to the observer. That is unauthorized person should not be able to identify in any sense between target image and secret image. For the data hiding, visual cryptography and visible mosaic image creation plays a very important role. II. Mosiac Image Mosaics are one form of art in which a large image is formed by a gathering of small images called tiles. First target image is selected; the given secret image is then divided into rectangular tiles, which then are fit into similar blocks in the target image. Next, the colour characteristic of each tile image is transformed to be that of the corresponding block in the target image, resulting in a secret mosaic image which looks like the selected target image [5].Various mosaics can be created for an image depending on the choice of tiles and the restriction in their placement. Mosaicing of image can be classified broadly into two methods such as direct method and feature based method. Direct Method uses information from all pixels. It iteratively updates an estimate of homography so that a particular cost function is minimized. Direct methods [6] attempt to iteratively estimate the camera parameters by minimizing an error function based on the intensity differences in the area of overlap. But this type of methods needs initialization, either by correlation or by manually setting some corresponding points. Sometimes phase-correlation is used to estimate the a few parameters of the homography. Feature based methods [7] mosaic the images by first automatically detecting and matching the features in the source images, and then warping these images together. Feature Based Methods are in general more accurate. It can handle large disparities. The images are mosaic in the number of way. By creating mosaic image a new technique for secure image transmission is proposed, which transforms a secrete image into mosaic images which look like similar to target image. The transformation of the images is controlled by a secret key, and only the person recover the secret image which known about that image from the mosaic image. The type of mosaic image used to secure data called as secret fragment mosaic image. The mosaic image is the result of rearrangement of the fragments of a secret image in disguise of another image called the target image.