In terms of contour-based image retrieval, distance histogram  is a method commonly applied for shape description, but it cannot reflect the spatial distribution of contour pixels and different shapes may be with the same distance histogram; so it will lead to a higher false retrieval rate.
Hence, for images polluted by noise, relatively higher false retrieval rate will be resulted in by adopting the DCV algorithm or IDCV algorithm.
Other features of the Claims database include Standardized Assignee names for each patent; annual updating of all Classification changes made by the USPO reflecting current and retrospective changes; and removal of all punctuation found in the Inventor name section, which will help eliminate false retrieval
Taken to its logical conclusion, these deficiencies will mean false retrievals
or missed searches or failure to provide catalog users with optimum search and retrieval conditions.
The superimposed coding system can cause false retrievals
when the superposition of several terms produces patterns that are identical to the codes of other assignable terms.