目的 分析常见的旋转操作对数码照片的原始性和Exif信息的影响。方法 选用佳能5DII单反数码相机拍摄的数码照片,在相机内部对照片进行旋转,并选用Windows照片查看器、ACDSee 17、光影看图、Picasa 3、和Lightroom5等5种常用图像浏览软件对数码照片进行旋转操作,对操作前后数码照片的MD5值和Exif信息进行对比。结果 佳能5DII相机内部的旋转操作,以及Windows照片查看器、ACDSee 17和光影看图对照片的旋转操作修改了照片Exif的部分信息,照片的原始性发生了变化,而Picasa 3和Lightroom5看图软件对照片的旋转操作没有改变照片的原始性。结论 旋转操作容易造成数码照片Exif部分信息的改变,破坏数码照片的原始性,在司法鉴定和法庭科学领域中对重要照片的保存和浏览需要采取恰当的方式和措施以确保照片的原始性不被改变。

For digital photos to be browsed, rotating the photos is often operated to facilitate watching them. However, such an operation is likely to modify the information of the photo and destroy its aboriginality, being adverse to preserve and identify those important ones. This paper analyzes the influence of rotation on the aboriginality and Exif information of digital photos. A digital photo, shot by a Canon 5D II digital SLR camera, serves as the original photo, being rotated inside the camera with its rotation function and also by each of the five popular kinds of image browsing software: Microsoft Windows Photo Viewer, ACDSee 17, Neoimage, Picasa 3 and Lightroom 5. Through analysis of MD5 and Exif information of the photo before and after rotation, the result shows that the MD5 has changed and Exif information modified when the rotation was taken inside the camera or by Microsoft Windows Photo Viewer, ACDSee 17 and Neoimage, yet not been influenced by Picasa 3 and Lightroom 5 because these two software usually use extra files to record the rotation process rather than directly manipulate the photo. Therefore, rotation is able to make the digital photo’s Exif information changed, destroying the photo’s aboriginality. In the judicial expertise and forensic practice, it is necessary to adopt right methods and measures to ensure the aboriginality of a photo when preserving and browsing it, especially for important ones.