The invention relates to a method for detecting and identifying
time-constant patterns in video signals of any video source, particularly
for automatically identifying advertising spots in television
broadcastings or the like transmissions by video signal analysis. The
invention further relates to a device for performing such a method and to
a special use of such a method. Regarding the method at least one
predetermined picture section of running-in video signals is written as
brightness matrix into a picture storage; the border courses of the actual
picture section are determined in the form of a directional field from the
brightness matrix and buffered as directional field matrix, and by
comparison of directional field matrixes of subsequent pictures of the
same picture section with the buffered matrix, time-constant portions are
identified wherein based on the time-constant portions of the directional
field a modified directional field matrix is determined for further
comparison measurements; if a sufficient time-constant pattern could not
be identified, it is switched over to further picture sections for further
reference measurements; after the successful determination of the
reference matrix by comparison of the directional field matrixes of
subsequent pictures of the same picture section with the reference matrix
by means of statistical methods information regarding the further presence
or absence of time-constant patterns can be derived.
