Abstract: A scene to be monitored (e.g., at a remote location or at a later time) is captured as a series of still images. These images are digitally encoded and stored in a digital memory for subsequent retrieval and viewing. If the scene includes a moving object (e.g., the side of a moving freight train), the images may be taken so that they are substantially mutually exclusive and collectively exhaustive of the moving object. During playback, two or more adjacent images may be displayed adjacent to one another so that any feature partly present in adjacent images is visible as a whole. If the observer is at a location remote from the point at which the images are taken, various techniques can be used to facilitate transmission of the image information (preferably in digital form) via relatively low-cost transmission links such as voice-grade telephone lines.

Abstract: To speed the transmission of video images via transmission lines which can be of relatively low grade (e.g., voice-grade telephone transmission lines), each video image is encoded as a plurality of pixels, and the bits for each pixel are transmitted in order of significance (i.e., the most significant bits for all pixels are sent first, then the next most significant bits for all pixels are sent, and so on). At the receiver the image is displayed as it is received, and transmission is terminated as soon as the observer of the display has sufficient information about the image. Although many other applications are possible, the illustrative embodiment is a remote railroad freight car identification system.