多張影像的低儲存快速解碼分享與比例顯像分享；被壓縮影像在頻率域的驗證與修復；多功能的混合型視覺加密分享
Abstract
本計畫為期三年，其目的是提出影像分享、修復及視覺加密技術。本年(第一年)的主題是多張影像的「低儲存空間快速解碼型」分享與「比例顯像型」分享。在第一主題中，我們提出以下系統：在單一編碼過程中分享掉多張影像，要求具有以下兩個時空並進的優點: (1).空間優勢：影像總輸入的大小與影像總輸出的大小比例（I/O size ratio）提高為1，亦即 1:1；(2).時間優勢：重建每個像素都只要常數次的運算，亦即O(1) ，因而不受影像張數影響。第一年第二個主題是多張影像的比例顯像型分享。在本主題中，我們希望設計出一種漸進式解碼方式，當取得t1份的JPEG偽裝碼時，可以解回第1群的所有影像。當取得t2（＞t1）份的JPEG偽裝碼時，可以解回第1群和第2群的所有影像。我們提出的多張影像分享法，同時擁有漸進式解碼、無失真還原(當收集到大部份的偽裝碼時)、以及儲存空間小的優點，所以非常適合將分享後之分存隱藏至偽裝媒體(stego media)，不會對要被藏入資料的媒體影像品質有顯著的影響。
This project is the first part of a three-year project. In Year 1, we deal with the following two topics: Topic A: design a space-saving fast-decoding sharing method for multiple images. This lossless method has two advantages simultaneously: (i) space: I/O size ratio is as high as 1:1；(ii) speed: reconstructing a pixel only needs a constant number of operations； and the number is independent of the number of secret images. (No reported lossless sharing method owns these two advantages simultaneously.) Topic B: design a multiple-images sharing method which has image by image security-dependent progressive decoding, lossless reconstruction of secret (when most of the shadows are collected), and compact size of shadows. An application of this topic is that, in a meeting, if some people are late, once the number of attendance has reached a threshold, some less important images can be decoded and discussed. When more and more people attend the meeting, the more important images can be decoded and discussed.
This project is the first part of a three-year project. In Year 1, we deal with the following two topics: Topic A: design a space-saving fast-decoding sharing method for multiple images. This lossless method has two advantages simultaneously: (i) space: I/O size ratio is as high as 1:1；(ii) speed: reconstructing a pixel only needs a constant number of operations； and the number is independent of the number of secret images. (No reported lossless sharing method owns these two advantages simultaneously.) Topic B: design a multiple-images sharing method which has image by image security-dependent progressive decoding, lossless reconstruction of secret (when most of the shadows are collected), and compact size of shadows. An application of this topic is that, in a meeting, if some people are late, once the number of attendance has reached a threshold, some less important images can be decoded and discussed. When more and more people attend the meeting, the more important images can be decoded and discussed.