1. Method for classifying an image in two or more dimensions, where an N-dimensional dataset comprising elements is caused to represent the image by at least two of the N dimensions constituting respective image axes, so that a certain pixel in the image corresponds to a certain element in the dataset, and by each element being associated with M numerical values each representing a measure of a property of the element in question, whereof at least one property represents image information in one respective sampled channel, characterized in that the method comprises identifying firstly a certain predetermined, variable geometric structure, the extension of which in at least two of the N dimensions in the dataset is determined in relation to a single element in the dataset and by at least one variable parameter, and secondly at least one geometric measure associated with said variable geometric structure, which geometric measure is arranged to measure a geometric property of a specific geometric structure in relation to other specific such geometric structures, and in that the method also comprises the steps that a computer or several interconnected computers a) is or are caused to store the dataset on a digital storage medium ( 101 ); b) for at least each element that corresponds to a pixel in the image, and for at least one of the M element properties, firstly is or are caused to determine a specific geometric structure ( 13 ; 23 ; 33 ; 43 ; 54 ; 64 ) which may be obtained in relation to the element ( 12 ; 22 ; 32 ; 42 ; 53 ; 63 ) in question and by choices of parameter value or values, for which specific geometric structure at least one of the said geometric measures is maximal at the same time as it is geometrically limited by individual elements or groups of elements the element property in question of which fulfills a certain predetermined criterion, and secondly is or are caused to calculate at least one of said geometric measures for the said specific geometric structure ( 102 ); c) in a database is or are caused to store an association between each element and the at least one calculated geometric measure for the element for each property for which a specific geometric structure has been calculated in the step b) ( 103 ); d) is or are caused to carry out a main classification of the dataset, which main classification is caused to be based upon a comparative measure between the respective sets of associated geometric measures of two elements, whereby each element is caused to be associated with a certain class in a main set of classes; ( 104 ) and e) on a digital storage medium is or are caused to store the image classified in the step d) in the form of a set of pixels with the same dimensions as the image, where each pixel is associated with the class in the main set of classes with which the element corresponding to the pixel in the image has been associated in the step d) ( 105 ); and in that the said variable geometric structure, measure and criterion are not selected so that the measure calculated in the step b) only constitutes a measure of the smallest distance between the element in question and the closest element which is associated with the element property in question.