Image Compression: Are Our Eyes Deceiving Us?
Digital compression of video images is a common occurrence. There are legitimate and laudatory reasons for such compression. Among those reasons are the fact that more data can be stored in a smaller amount of storage space, data can be easily transmitted electronically, and data can be searched more readily. However, the first...
Editing of Images: When Do You Cross the Line?
Related to concerns with authentication, one of the most pervasive suspicions regarding digital image evidence is that the images have been surreptitiously edited in such a manner as to present a false picture of what really happened. Such editing may include deletion or insertion of images, changing the order in which images appear,...
Image Accuracy: Why the Correct Aspect Ratio Matters
Part of the process of authenticating a video image is to show that the image is an accurate depiction of what the camera recorded. One important technical issue bearing upon image accuracy that must be considered is aspect ratio (the height to width ratio of the image). It is not uncommon to see...