Method and apparatus for representing a group of images

1. A method of representing a group of images using at least one processor to process signals corresponding to the images, the method comprising:

obtaining, using a processor, an image descriptor which is an image dominant colour representation for each image in the group of images, where each of the image descriptors has one or more components including at least one image dominant colour value;

deriving, using a processor, a group descriptor which is a group dominant colour representation expressing the group of images in terms of one or more of dominant colour values by combining one or more components of a plurality of the image descriptors based on proximity of dominant colours in colour space; and

storing the group descriptor as a descriptor for the group of images, wherein said combining of components based on proximity comprises

retrieving first and second image descriptors, each of said first and second image descriptors including a plurality of dominant colour values,

determining the distance between each dominant colour value in said first image descriptor and each dominant colour value in said second image descriptor, to obtain a plurality of distance measurements,

selecting the smallest distance measurement,

selecting the dominant colour value in the first image descriptor and the dominant colour value in the second image descriptor corresponding to said smallest distance measurement, and

combining said selected dominant colour values to form a new dominant colour value in a new descriptor.

2. A method of claim 1 where each of the image dominant colour representations has one or more components including optionally for each dominant colour value, a variance indicating colour distribution variance of the image with respect to the dominant colour value, a weight indicating the influence of the dominant colour in the image, the number of dominant colours in the image, and spatial homogeneity of pixels corresponding to the dominant colours in the image.

3. A method as claimed in claim 1 involving temporally or spatially sub-sampling the group of images.

4. A method as claimed in claim 3 wherein images are omitted or included depending on their similarity to other images in the group.

5. A computer-readable storage medium storing computer-executable process steps for implementing a method as claimed in claim 1 .

6. A computer system comprising:

an image database storing images or groups of images;

a descriptor database storing descriptors for the images or groups of images in the image database;

a control unit configured to perform the method as claimed in claim 1 .

7. An apparatus comprising:

an image database storing images or groups of images;

a descriptor database storing descriptors for the images or groups of images in the image database; and

a processor configured to perform the method according to claim 1 .