The Study of Image Tampering Detection

• Main Authors: Chuang Lou Zou, 莊潤洲
• Other Authors: Chuang Chin chen
• Format: Others
• Language: en_US
• Published: 2000
• Online Access: http://ndltd.ncl.edu.tw/handle/58825581948530138596

碩士 === 國立中正大學 === 資訊工程研究所 === 88 === Nowadays, Internet has become more and more popular. However, images are most oftenly used in Internet. Images can be used as the trademarks of company symbolization, electronic commerce (EC), multimedia, etc. However, there are also some security issues of images. Among them, the illegal like illegal copy and modification of image is a popular security problem which oftenly occurs in our daily life. Therefore, how to protect the intellectual property of images is an important research topic. The thesis planes to use image authentication to protect the images. Based on the image authentication, the modified places of the images will be pointed out; thus the images can preserve the image integrity. This thesis proposes two new methods for image authentication. The first method uses the RSA signatures and quadtree structure to achieve the image integrity. Based on those digital signatures, we can claim the authorship of the image and detect efficiently whether the image has been modified or not. On the other hand, we use quadtree structure to organize digital signatures; thus the detection procedure will be more efficient. The traditional image authentication methods cannot allow JPEG lossy compression since the JPEG lossy compression may destroy the signatures embedded in images. However, JPEG lossy compression method is often required and popularly used everywhere. Thus, the JPEG lossy compression should be taken into consideration. To improve the traditional methods, we propose a new image authentication that not only can prevent images tampered with but also allow reasonable JPEG lossy compression. Our method will extract some significant DCT coefficients and set a compression tolerant range of them. An extracted DCT coefficient will be survived after the image is not further modified or lossily compressed.