A histogram-based segmentation of images in a video signal via color moments is initialized by a user defining regions in objects of interest from one or more images, key frames or pictures of the video signal. For each rectangle a normalized average color moment and associated co-variance matrix are determined which define a color class for that rectangle. From the normalized average color moment and associated co-variance garbage parameters are generated. Segmentation is then performed on a block basis on each image of the video sequence, a normalized color moment being generated for each block. Using a log likelihood test the closest color class for the block is determined. Based upon the closest color class and the garbage parameters for that color class a final determination is made in a two stage test as to whether the block belongs to the closest class or to a "garbage" class. All the continguous blocks that belong to a specific color class form the segmented object, and all of the objects are segmented in this manner.

A histogram-based segmentation of an image, frame or picture of a video signal into objects via color moments is initiated by defining a relatively large area within the object. The defined area is characterized by its color information in the form of a limited set of color moments representing a color histogram for the area. Based upon the set of color moments, color moments generated for small candidate blocks within the image, an automatically generated weighting vector, distance measures for the blocks from a central block in the object and a tolerance the area is grown to encompass the object to the extent of its boundaries. The initial set of color moments are then updated for the entire object. Those candidate blocks within the object serve to segment the object from the image.

Methods are provided for extracting color distortion data from multimedia data in a content-based multimedia search and for searching multimedia data based on the extracted color distortion data. A method is also provided for generating multimedia data to be used in the content-based multimedia search. The color distortion data includes hues of the distorted color identifying which color affected such a distortion and intensity data representing how much color distortion data affected such a distortion.

The present invention is a method for presenting the content of images, in which, out of images that include at least moving images and can be segmented into a plurality of scenes, groups of two or more key images included in the individual scenes are extracted, and a digest screen of the images, which include the groups of key images, is organized. The method is characterized in that a scene segmenting step of generating individual segmented scenes and the following three steps for each scene are provided: a key-image extracting step, a preceding-and-following-key-image extracting step of extracting at least one still image time-oriented preceding the key image and/or at least one still image time-oriented following the key image, and a key-image weighting step of assigning a weight to the key image on the basis of a predetermined measure. Moreover, at least, a scene organizing step of disposing the preceding and following key images in the neighborhood of the corresponding key images, and enabling or disabling the display of the key images and expanding or contracting the key images according to the corresponding weights to organize a digest screen and a screen displaying step of displaying the digest screen are provided.

The frequency of the dot clock in an image display device is adjusted by calculating a first image characteristic from the differences between adjacent picture elements, varying the phase of the dot clock, determining whether the frequency of the dot clock is correct from the way the first image characteristic varies according to the phase of the dot clock, and changing the frequency if it is incorrect. The first image characteristic is, for example, the maximum difference, the histogram distribution of the differences, or a ratio calculated from the histogram. The phase of the dot clock may be adjusted according to a second image characteristic, such as the difference between a single pair of pixel values, which is also measured over a range of dot-clock phase settings.