1. A method of indexing digitized non-text entities in a data collection comprising: retrieving basic information pertaining to at least one distinctive feature and at least one locator for each digitized non-text entity in a set of entities from the data collection using an indexing input device, using an index generator of the indexing input device to generate searchable index information related to the entities in the set on the basis of the basic information and storing the index information in an index database of a storage device, wherein the index information for a particular digitized non-text entity is generated by the index generator on the basis of at least one rank parameter derived from the basic information, the at least one rank parameter being indicative of a degree of relevance for at least one distinctive feature with respect to the digitized non-text entity, wherein the at least one rank parameter is based on a first rank component that is generated by ranking individual distinctive features related to the digitized non-text entity on the basis of a relative occurrence of the individual distinctive features with respect to multiple copies of the digitized non-text entity in the data collection, and wherein the at least one rank parameter is further based on a second rank component that is generated by ranking at least one individual distinctive feature related to the digitized non-text entity on the basis of a position of the least one individual distinctive feature in a descriptive field associated with the digitized non-text entity, wherein the generating of the rank parameter involves a combination of the first rank component with the second rank component, and wherein the first rank component and the second rank component are combined according to the expression: ( α ⁢ ⁢ Γ ⁢ ) 2 + ( β ⁢ ⁢ Π ) 2 α 2 + β 2 where Γ represents the first rank component, π represents the second rank component, α represents a first merge factor and β represents a second merge factor.