Image composite authentication using a single shadow observation

作     者：CAO XiaoChun ZHAO HanDong WANG Chuan ZHANG Wei 

作者机构：State Key Laboratory of Information Security Institute of Information Engineering Chinese Academy of Sciences 

出 版 物：《Science China(Information Sciences)》 (中国科学:信息科学(英文版))

年 卷 期：2015年第58卷第9期

页      面：122-134页

核心收录：

学科分类：08[工学] 080203[工学-机械设计及理论] 0802[工学-机械工程] 

基　　金：supported by National Natural Science Foundation of China(Grant Nos.61422213,61332012) 100 Talents Programme of the Chinese Academy of Sciences 

主　　题：image forensics solar shadow sun elevation exchangeable image file geometry-based technique 

摘      要：The paper presents a novel method for image composite authentication based on a single shadow in an outdoor image. Existing methods based on the shadow geometry consistency involve more than two shadow observations. We relax the requirement of two shadow observations in the same scene. As a trade-off,we use the information in EXIF(Exchangeable Image File) based on which the ground truth sun elevation is calculated. We also estimate the sun elevation based on geometric constraints the scene provides, whose consistency serves as the cue to authenticate image forgery. It is the first attempt, to our best knowledge, to make use of sun elevation with shadow of one object to authenticate outdoor images. Also, the novel use of GPS(Global Positioning System), and Date and Time data of captured image makes image forensics possible even in one image containing a single shadow. Experimental results on both the synthetic data and visually plausible images demonstrate the performance of the proposed method.