A novel methodology to represent the contents of a video sequence is presented. The representation is used to allow the user to rapidly view a video sequence in order to find a particular point within the sequence and/or to decide whether the contents of the sequence are relevant to his or her needs. This system, referred to as content-based browsing, forms an abstraction to represent each shot of the sequence by using a representative frame, or an Rframe, and it includes management techniques to allow the user to easily navigate the Rframes. This methodology is superior to the current techniques of fast forward and rewind because rather than using every frame to view and judge the contents, only a few abstractions are used. Therefore, the need to retrieve the video from a storage system and to transmit every frame over the network in its entirety no longer exists, saving time, expenses, and bandwidth.

This paper presents a novel approach to processing encoded video sequences prior to decoding.Scene changes may be easily detected using DCT coefficients in JPEG and MPEG encoded video sequences.In addition, by analyzing the DCT coefficients, regions of interest may be isolated prior to decompression, increasing efficiency of any subsequent image processing steps, such as edge detection.The results are currently used in a video browser, and are part of an ongoing research project in creating large video databases.The procedure is presented in detail and several examples are exhibited.

Two major structuring element decomposition techniques are compared, and the superiority of the two pixel decomposition techniques over the cellular decomposition technique is shown in terms of the number of pipeline stages. As for the general structuring function decomposition, to the authors' knowledge, there is no efficient algorithm that has been found. The difficulty can be overcome by using an adequate representation of the general gray-scale structuring function. Representing a gray-scale image as a specific 3-D set, i.e. an umbra, makes it easier to shift all morphological theorems from the binary domain to the gray-scale domain; however, a direct umbra representation is not appropriate for the general gray-scale structuring function decomposition. The authors also provide a morphologically realizable representation and decomposition for the general gray-scale structuring function and show recursive algorithms which are pipelineable for efficiently performing gray-scale morphological operations.>