Method for obtaining a mega-frame image fingerprint for image fingerprint based content identification, method for identifying a video sequence, and corresponding device

A method for obtaining a mega-frame image fingerprint from a temporal section of a video sequence for fingerprint based identification of a video sequence, comprising:

• selecting a temporal section defined by boundary image frames in the video sequence, said boundary image frames delimiting a sequence of image frames in the video sequence;
• selecting a maximum of k stable image frames j in the selected temporal section, by computing a sum of similarity distances between a number of neighbor image frames of a candidate stable image frame j in the selected temporal section and determining the k minimum computed sums of similarity distances in the temporal section, while respecting an interspacing of at least n image frames between the stable image frames j;
• for each of the selected maximum k stable image frames j, selecting an image frame within a selection window of a width of M frames, the selection window being centered in the selected stable image frame j, the selected image frame replacing the selected stable image frame j;
• and
• for each of the selected maximum k stable image frames j, computing an image fingerprint, and constructing a mega-frame image fingerprint data structure that comprises the computed image fingerprints.

A method for identifying a video sequence, wherein it comprises:

• selecting a temporal section of the video sequence defined by boundary image frames in the video sequence, said boundary image frames delimiting a sequence of image frames in the video sequence;
• selecting a maximum of k stable image frames in the selected temporal section, by computing of a sum of similarity distances between a number of neighbor image frames of a candidate stable image frame j in the selected temporal section and determining the k minimum computed sums of similarity distances in the temporal section, while respecting an interspacing of at least n image frames between the stable image frames;
• for each of the selected maximum k stable image frames j, computing an image fingerprint, and constructing a mega-frame image fingerprint data structure that comprises the computed image fingerprints;
• for each of the selected maximum k stable image frames j, selecting an image frame within a selection window of a width of M frames, the selection window being centered in the selected stable image frame j, the selected image frame replacing the selected stable image frame j;
• comparing the constructed mega-frame image fingerprint data structure with mega-frame image fingerprint data structures from an image fingerprint data base;
• and
• said video sequence being identified by one of said data structures in said data base, if upon said comparing a data structure is found in said data base that corresponds to said constructed data structure.

A device for obtaining a mega-frame image fingerprint from a temporal section of a video sequence, comprising:

• a temporal section selector configured to select a temporal section of the video sequence, the temporal section being defined by boundary image frames in the video sequence, the boundary image frames delimiting a sequence of image frames;
• a stable frame selector configured to select a maximum of k stable image frames j in the selected temporal section, by computing of a sum of similarity distances between a number of neighbor image frames of a candidate stable image frame j in the selected temporal section and determining the k minimum computed sums of similarity distances in the temporal section, while respecting a interspacing of at least n image frames between the stable image frames j;
• a best frame selector configured to select, for each of the selected maximum k stable image frames j, an image frame within a selection window of a width of M frames, the selection window being centered in the selected stable image frame j, the selected image frame replacing the selected stable image frame j;
• a data structure constructor configured to compute an image fingerprint for each of the selected maximum k stable image frames j, and configured to construct a mega-frame image fingerprint data structure that comprises the computed image fingerprints.

A device for identifying a video sequence, the device comprising:

• a temporal section selector configured to select a temporal section of the video sequence defined by boundary image frames in the video sequence, said boundary image frames delimiting a sequence of image frames in the video sequence;
• a stable frame selector configured to select a maximum of k stable image frames in the selected temporal section, by computing a sum of similarity distances between a number of neighbor image frames of a candidate stable image frame j in the selected temporal section and determining the k minimum computed sums of similarity distances in the temporal section, while respecting an interspacing of at least n image frames between the stable image frames;
• a best frame selector configured to select, for each of the maximum k determined stable image frames, an image frame within a selection window of a width of M frames, the selection window being centered in the selected stable image frame j, the selected image frame replacing the selected stable image frame j;
• a data structure constructor configured to compute an image fingerprint for each of the determined maximum k stable image frames j, and for constructing of a mega-frame image fingerprint data structure that comprises the computed image fingerprints;
• a data structure comparator configured to compare the constructed mega-frame image fingerprint data structure with mega-frame image fingerprint data structures from an image fingerprint data base;
• and
• said video sequence being identified by one of said data structures in said data base, if upon said comparing a data structure is found in said data base that corresponds to said constructed data structure.