Method and apparatus for selectively altering a televised video signal in real-time
The method and apparatus operates in a television receiver to identify unwanted broadcast segments, such as commercial advertisements, of a television signal in real-time for the purpose of selectively altering the television display during each unwanted segment. A signature pattern associated with each segment of the television signal is detected and compared to stored signature patterns representative of selected segments such as commercial advertisement segments. If the signature pattern matches one of the stored signature patterns, the segment is thereby immediately identified as being one of the selected segments and is processed in real-time to mute or otherwise alter the television signal during the segment. If the signature pattern of the segment does not match any of the stored signature patterns, the segment is analyzed to determine whether the segment is nevertheless a selected segment and, if so, its signature pattern is stored along with the stored signature patterns.
This is a continuation-in-part of co-pending application Ser. No. 09/452,040 filed Nov. 30, 1999, which is a continuation of application Ser. No. 08/742,983 filed Nov. 1, 1996, now U.S. Pat. No. 6,002,443.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention relates to television signal processing systems and in particular to television signal processing systems for detecting selected segments of a television signal such as commercial advertisement segments.
2. Description of Related Art
It has long been a desire of many television viewers to have a system which automatically detects selected segments of a television signal such as commercial advertisements or other unwanted broadcast segments in real-time during a television broadcast for the purposes of, for example, muting the audio portion of the television broadcast during the unwanted broadcast material. Although a wide variety of techniques have been developed for detecting selected segments of television signals, heretofore there have been no sufficiently effective and economical systems that automatically operate in real-time for muting the television signal during the selected segments or for similar purposes.
Examples of broadcast segment detection systems include systems for detecting commercial advertisements during the playback of a television program on a video cassette recorder (VCR) for the purpose of controlling the VCR to skip or scan over the commercial advertisements during playback such that a viewer may watch the recorded television program without significant commercial advertisement interruptions. One particularly effective system is described in U.S. Pat. No. 5,333,091 entitled “Method and Apparatus for Controlling a Videotape Player to Automatically Scan Past Recorded Commercial Messages” and sold under the trademark “Commercial Advance.” With the system of U.S. Pat. No. 5,333,091, an automatic editing device is coupled between a conventional VCR and a conventional television set. As a broadcast program is recorded on a videotape by the VCR, the editing device detects and records the timing and duration of selected events, such as black frames combined with low audio, that separate segments of the broadcast and creates a time-based map of the selected events. After the recording is completed, the editing device analyzes the time-based map and determines therefrom which segments are commercial advertisement segments and which are program segments. The editing device then records control signals on the videotape prior to and following the commercial advertisement segments. Upon playback, the control signals control the VCR to fast-scan over the commercial advertisement segments so that the recorded broadcast can be viewed substantially without interruption. Related techniques are described in U.S. Pat. No. 5,455,630 and in PCT application PCT/US94/00223 published as WO 94/16442.
Although the systems of U.S. Pat. Nos. 5,333,091 and 5,455,630 and PCT application PCT/US94/00223 are very effective in skipping over commercial advertisements and other unwanted broadcast material during the playback of a recorded broadcast program on a videotape, the systems do not operate in real-time during a received broadcast.
Other examples of broadcast segment detection systems include systems for detecting commercial advertisements during the recording of a television program on a VCR for the purposes of controlling the VCR to skip the commercial advertisements during recording such that a viewer may later watch the recorded television program without any commercial advertisement interruptions whatsoever. An example is a system described in U.S. Pat. No. 4,602,297 entitled “System for Editing Commercial Messages from Recorded Television Broadcasts” which stores and delays the output of a received broadcast signal to a VCR until it can determine whether the delayed portion of the broadcast signal includes commercial advertisements. To this end, the system detects commercial advertisements or groups of commercial advertisements within the delayed portion by detecting amplitude drops in the broadcast signal and determining whether time intervals between the amplitude drops correspond to normal durations of commercial advertisements or groups of commercial advertisements. The system then outputs only those portions of the delayed signal to the VCR that do not correspond to commercial advertisements of groups of commercial advertisements. Hence, the broadcast signal is recorded without commercial advertisements for future playback. However, the system does not operate in real-time to detect commercial advertisements within a received broadcast signal. Rather the system instead requires that the received broadcast signal be temporarily stored and delayed. Commercial advertisements may each be one minute or perhaps more in length thereby requiring a significant amount of storage for temporarily storing portions of the broadcast signal and thereby requiring a system which is not sufficiently economical for most purposes.
Other examples of systems for detecting commercial advertisements during the recording of a television program are described in U.S. Pat. No. 4,750,052 entitled “Apparatus and Method for Automatically Deleting Selected Program Intervals from Recorded Television Broadcasts” and U.S. Pat. No. 4,782,401 entitled “Editing Method and Apparatus for Commercials During Video Recording”, both of which also operate to detect commercial advertisements based upon intervals occurring between amplitude drops or other fades in a received broadcast signal. Rather than storing and deleting the received signals prior to output to a VCR, however, the systems of U.S. Pat. Nos. 4,750,052 and 4,782,401 record the signals on a videotape using a VCR and control the VCR to rewind at the end of each commercial advertisement or group of advertisements such that further program signals are recorded over the commercial advertisements. As with the previously described system, the systems of U.S. Pat. Nos. 4,750,052 and 4,782,401 do not operate in real-time and are not sufficiently economical for most purposes.
Moreover, none of the aforementioned systems for detecting broadcast segments during the recording of a television program operate in real-time for the purpose of, for example, muting the audio during commercial advertisements or other broadcast segments.
Still other examples of broadcast segment detection systems include systems for detecting commercial advertisements in broadcast television signals for the purposes of verifying that selected commercial advertisements are being broadcast on the proper days and at the proper times. Examples include U.S. Pat. No. 5,504,518 entitled “Method and System for Recognition of Broadcast Segments” wherein stored digitized segments of broadcast signals are processed by an expert system to determine whether any particular segment corresponds to a selected segment of interest, such as a selected commercial advertisement. Segments that cannot be identified by the expert system, such as new or otherwise unknown segments, are routed to a human operator for verifying that the segment represents a commercial advertisement rather than a portion of a television program. Selected segment information such as the date and time of broadcast of the segments of interest are recorded and tabulated in a report for use by, for example, broadcast advertisers for verifying that the selected segments were broadcast on the proper dates and at the proper times. As part of its analysis of the segments, the expert system compares broadcast signatures with a database of signatures. A variety of techniques are described for defining and detecting signatures. The expert system also considers various cues including the lengths and relative groupings of segments and the intervals there between. No real-time analysis appears to be performed by the expert system or by the human operator.
Another system for commercial advertisement broadcast verification is described in Japanese Laid-Open Patent Application No. 1-174192, of Sony Corporation, entitled “Television Signal Processing Unit” wherein an entire days worth of broadcast programs are recorded on videotape. The recorded broadcasts are analyzed to identify commercial advertisement segments by intervals therebetween as detected by luminance signal considerations. The commercial advertisements, and only the commercial advertisements, are then output and recorded on a second videotape. The second videotape thereby contains a day's worth of commercial advertisements in extracted form that may be viewed by a human operator for broadcast verification purposes. Again, no real-time detection of commercial advertisements is performed.
Examples of systems for detecting broadcast segments, such as commercial advertisement segments, which have some real-time detection capability include U.S. Pat. Nos. 4,420,769 entitled “Device for the Automatic Editing, at the Receiver, of Unwanted Program Material from Broadcast Electrical Signals” and U.S. Pat. No. 4,750,213 entitled “Method and System for Editing Unwanted Program Material from Broadcast Signals”. U.S. Pat. No. 4,420,769 describes a system wherein a human operator identifies program segments to be eliminated from a broadcast signal causing a digital code word or signature for the segment to be stored in memory. Subsequently, if the same segment is encountered, the system automatically compares digitized portions of the received signal with the stored signatures to recognize the segment and then to blank out or otherwise eliminate the segment in real-time. One significant problem with this system is that a human operator must first detect program segments to be eliminated. Also, a significant amount of data processing is required to establish and compare the signatures in a reliable manner. U.S. Pat. No. 4,750,213, by the same inventor, sets forth improvements intended, in part, to reduce the processing time required. The system of U.S. Pat. No. 4,750,213 also includes a delay or other storage device for allowing a received signal to be delayed until a determination can be made by the human operator as to whether a particular segment of the received signal should be eliminated. If so, the received, delayed signal is output with the selected segment blanked out or otherwise eliminated. Although U.S. Pat. No. 4,750,213 may represent an improvement over U.S. Pat. No. 4,420,769, it shares the disadvantage that a human operator must detect program segments to be eliminated.
Another example of a system which has some real-time detection capability is U.S. Pat. No. 5,151,788 entitled “Method and Apparatus for Identifying and Eliminating Specific Material from Video Signals” wherein commercial advertisement broadcast segments are distinguished from program segments by the relative level of “activity” within the beginning of each segment. If the activity level is high, the segment is presumed to be a commercial advertisement. The system detects the amount of activity within the first few seconds of a segment following a blank frame and operates to mute or otherwise eliminate the remaining portions of the segment if the detected activity level is representative of a commercial advertisement. The system may control a VCR to stop recording for the remainder of the segment. The patent describes that the optimum time period during which the activity level should be detected is 8 seconds. One disadvantage of the system is that the detection of commercial advertisements based upon an activity level is likely to be unreliable for many broadcasts and, even when the system does correctly detect a commercial advertisement, that detection does not occur until 8 seconds into the commercial advertisement.
Other references that relate to systems for detecting selected segments of a broadcast signal such as commercial advertisement segments of a television signal are described in the following references: U.S. Pat. No. 3,919,479 entitled “Broadcast Signal Identification System”; U.S. Pat. No. 4,229,765 entitled “Remote Audio and Brightness Control System for a Television”; U.S. Pat. No. 4,230,990 entitled “Broadcast Program Identification Method and System”; U.S. Pat. No. 4,259,689 entitled “Television Advertising Editing System”; U.S. Pat. No. 4,333,110 entitled “Television Editing System”; U.S. Pat. No. 4,390,904 entitled “Automatic Circuit and Method for Editing Commercial Messages from Television Signals”; U.S. Pat. No. 4,667,466 entitled “Broadcast Program Identification Method and Apparatus”; U.S. Pat. No. 4,697,209 entitled “Methods and Apparatus for Automatically Identifying Programs Viewed or Recorded”; U.S. Pat. No. 4,739,398 entitled “Method, Apparatus and System for Recognizing Broadcast Segments”; U.S. Pat. No. 4,752,834 entitled “Reciprocating Recording Method and Apparatus for Controlling a Video Recorder so as to Edit Commercial Messages from a Recorded Television Signal”; U.S. Pat. No. 5,019,899 entitled “Electronic Data Encoding and Recognition System” and European Patent Application Publication No. 0161512 entitled “Program Identification System”.
Hence various techniques have been developed for detecting selected broadcast segments such as commercial advertisements within a television signal. None of the techniques described above, however, are effective for reliably and automatically detecting broadcast segments in real-time without the need of a human operator. Accordingly, it would be desirable to provide a simple, inexpensive system which reliably detects selected segments of a broadcast signal without requiring a human operator and wherein, either immediately or after some period of time, all or most selected segments can be detected in real-time.
SUMMARY OF THE INVENTION
In accordance with the invention, a method and apparatus is provided to identify selected segments of a television broadcast signal in real-time for the purpose of muting or otherwise altering the video and/or audio portions of the signal during the selected segments. Hereinafter “selected segment” refers to any selected portion of a broadcast signal including, for example, unwanted broadcast segments such as commercial advertisement segments. In one embodiment, the method includes the steps of detecting a signature pattern associated with the beginning of a received segment of the television signal and comparing the signature pattern to stored signature patterns representative of selected segments. If the signature pattern matches one of the stored signature patterns, the received segment is thereby immediately identified as being one of the selected segments and can be processed accordingly in real-time to, for example, mute the audio and video portions of the received segment.
If the signature pattern of the received segment does not match any of the stored signature patterns, the received segment may be analyzed to determine whether it is nevertheless one of the selected segments and, if so, its signature pattern is stored along with the stored signature patterns. The analysis to determine whether the received segment is one of the selected segments even though its signature does not match any of the stored signatures may be performed by, for example, detecting the length of the received segment upon its completion and then determining whether the length of the received segment matches any of a pre-determined set of permissible lengths for selected segments. If so, the segment is identified as being a selected segment and its signature pattern is stored along with the other stored signature patterns such that, the next time the same segment is received, its signature will then match one of the stored signatures and therefore the received segment will be identified promptly as a selected segment. A segment may also be manually designated as a selected segment, which likewise results in the corresponding signature being stored.
In one implementation, no stored signatures are initially provided. Hence, the first time any particular selected segment is encountered, it is not immediately identified as being a selected segment and therefore the segment will not be muted. However, the next time the same segment is encountered, the segment will be immediately and automatically muted. As more and more selected segments are encountered and their respective signature patterns stored, the more and more likely it becomes that any particular selected segment encountered while watching a television program will be promptly detected based upon its stored signature and automatically muted. Hence, even though no stored signatures are initially provided, a database of signatures is soon developed. Also, the selected segment detection method may be performed even while the television set is otherwise not in use to thereby detect and store segment signatures in a background mode to quickly develop a database of signatures. Alternatively, a database of the signatures of common segments, such as common commercial advertisement segments, may be initially provided at the time of manufacture or subsequently downloaded such that the common segments are thereby automatically muted even the first time they are encountered.
For many television broadcast systems, commercial advertisements appear in groups of two or more. When used in connection with such systems, the method of the invention may operate to not only mute the detected commercial advertisements of a commercial advertisement group but rather to mute the entire group, including other unwanted broadcast segments appearing within the group, such as station breaks, news bulletins, public service announcements, etc.
Depending upon the implementation, the method identifies the beginning of a segment by detecting pre-determined event markers which separate segments. When implemented for use in North America, the method may, for example, identify a period of one or more black frames combined with low audio as being an event marker representative of the beginning of a segment. When implemented for use in Europe, the method may instead identify periods of one or more colored frames, such as blue frames, combined with low audio as being an event marker. When implemented for use in Japan, the method may instead identify a frame break combined with a period of low audio as being an event marker. In any case, once an event marker denoting the beginning of a broadcast segment is detected, the method promptly extracts a signature from the segment for comparison against stored signatures. The signature may, for example, be a binary hash code representative of whether selected lines of a selected frame near the beginning of the segment exceed pre-determined luminance threshold levels. By extracting the signature near the beginning of the segment, a matching signature may be detected and the segment muted or otherwise altered before a significant portion of the segment has been displayed. Preferably, the signature is based on frames appearing during the first one second of the segment.
BRIEF DESCRIPTION OF THE DRAWINGS
The features, objects, and advantages of the present invention will become more apparent from the detailed description set forth below when taken in conjunction with the drawings in which like reference numerals identify correspondingly throughout and wherein:
DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS
Referring to the Figures, exemplary embodiments of the invention are described for use with a television set for detecting “unwanted segments”, such as commercial advertisements, in a television broadcast signal. Unwanted segments may also include other segments designated by a viewer, such as segments that may be deemed by a parent to be inappropriate for viewing by children. Upon detection of an unwanted segment, the audio and video components of the received broadcast signal may be muted. Alternatively, a secondary signal source may be substituted for viewing during the unwanted segment. Initially, an overview is provided with reference to the block diagrams and timing diagrams of
Detection of commercial advertisement segments is achieved as follows. Within detecting and muting system 108, the television signal is first routed through a broadcast segment event marker and signature detector 110 which detects event markers separating broadcast segments of the television signal and, for each segment, detects a signature. A broadcast segment may be a commercial advertisement segment or a portion of a television program, movie, news show, “infomercial” etc. hereinafter referred to as program segments. As noted, the broadcast segments are separated by event markers. In the exemplary implementation which is for use in North America, an event marker is a period of one or more black frames combined with low audio. When implemented for use in Europe, the event marker may also be a period of one or more colored frames, such as blue frames, combined with low audio. When implemented for use in Japan, an event marker is a frame break combined with a period of low audio extending from slightly before to slightly after the frame break.
Each unique broadcast segment has a unique signature. The signature may be any unique characteristic of the segment that can be used to distinguish one segment from another. As will be described below, in one exemplary implementation, the signature may be a bit string hash code representative of whether each of a set of selected lines of a selected frame of a received segment has an average luminance level that exceeds a pre-determined threshold. The selected frame may be, for example, the tenth frame following the completion of the event marker marking the beginning of the segment. The selected lines may be, for example, the first 64 odd lines of the frame beginning at line 23. Other signatures may alternatively be employed.
Referring again to
Hence, the system mutes the output signal during a detected commercial advertisement segment. Additionally, the system may continue the mute throughout an entire commercial advertisement group containing the detected commercial advertisement segment. To this end, the system determines when the commercial advertisement group began and continues muting for at least some minimum predetermined time period, such as two minutes, following the beginning of the group. In this manner, non-commercial advertisements of the group are muted as well as any commercial advertisements of the group not having a previously stored signature. The manner by which the system determines the beginning of a commercial advertisement group for the purposes of muting the entire group will be described below.
In some implementations, “muting” means that the amplitudes of the audio and luminance components of the output signal are reduced such that the viewer of monitor 104 sees a dimmed image and hears reduced audio levels. In more general terms, “muting” is used to refer to any alteration of the broadcast signal. Such alteration may include, in addition to reducing audio and video levels, switching to an alternate signal source.
Referring again to
Hence, commercial advertisement detecting and muting system 108 operates to mute in real-time any broadcast segment having a signature matching one of the signatures of memory unit 128. Naturally, commercial advertisements will be received for which a signature was not previously recorded in memory unit 128 and the commercial advertisement will therefore not be muted (unless it is part of an entire group of commercial advertisements being muted). The library of signatures in memory unit 128 may be built up in various ways. One approach automatically adds a new signature when a commercial advertisement is detected with a signature not already in the library. Detecting and muting system 108 may be provided with a means for determining whether a broadcast segment, having a signature that does not match any signature recorded in the database, nevertheless is a commercial advertisement segment. Once a determination is made that a broadcast segment is a commercial advertisement segment or other selected segment, the signature of the segment is added to the database such that the segment can be muted in real-time the next time it is encountered.
Another approach adds a new signature upon receipt of an operator command. This “manual” approach allows the television viewer to designate a particular commercial advertisement or other broadcast segment for muting whenever it is re-broadcast. The remote control unit for television set 100 may be provided with a button or other control that effectively operates as a “kill this commercial” switch. Of course, the manual and automatic signature capturing process are not mutually exclusive.
Signatures may also be pre-stored in memory unit 128 prior to delivery of television set 100 to the consumer or may be downloaded periodically from a central storage unit. Signatures may be downloaded on an otherwise unused broadcast channel or may be encoded within an active broadcast channel, such as in the vertical blanking interval. Signatures may also be downloaded via a telephone connection or via a dedicated communications connection.
Automatic Addition of Signatures to Library
In some implementations of the invention, commercial advertisement segments may be distinguished from program segments automatically for the purpose of creating a library of signatures. The automatic recognition process relies on the observation that commercial advertisement segments almost always appear in groups of two or more and are each of one or more relatively short pre-determined lengths such as 15 seconds, 30 seconds and 60 seconds. The groups are typically at least two minutes long.
The automatic determination of whether a broadcast segment is a commercial advertisement segment or other selected segment, assuming that its signature does not match a stored signature, is achieved as follows. As noted above, and as illustrated in
Hence, if a second marker occurs, for example, 15, 30 or 60 seconds following a first event marker, a determination is made that the segment between the first and second event markers is therefore probably a commercial advertisement or other selected segment and the signature detected following the first event marker is added to the signatures stored in memory unit 128 (
In practice, for North American broadcast systems, the lengths of commercial advertisements often deviate slightly from the standard 15, 30 and 60 second durations. Accordingly, the system searches for subsequent event markers within a range of time centered around each expected event marker time. For a 30 second commercial advertisement, the system may search, for example, for event markers occurring 28 to 32 seconds following a previous event marker.
In any case, if a determination is made that a broadcast segment is a commercial advertisement, then the next time the same commercial advertisement segment is received the following occurs. The signature of the commercial advertisement segment is again detected by detector 110 and compared against those stored in memory unit 128. Upon determining that the newly detected signature matches the previously stored signature, the commercial advertisement segment is muted in real-time. In this manner, the system builds a database of commercial advertisement segment signatures and each commercial advertisement segment is typically displayed only once in its un-muted form. Thereafter, as long as the signature of the commercial advertisement segment remains in the database, the segment is detected and muted in real-time. Hence, even if the signature database of memory unit 128 is initially empty, a database of commercial advertisement signatures is developed and soon all or most commercial advertisements that are commonly shown are detected and muted. Of course, it is possible for a non-commercial segment of a desired television program to be 15, 30 or 60 seconds long such that its signature will be added to the database along with those of commercial advertisements. Hence, the next time the same television program is received the segment will be muted under the assumption that it is a commercial advertisement. This is not a particularly significant problem. The viewer merely over-rides the mute and continues to view the program. Moreover, television programs are not typically viewed repeatedly and, as will be described below, the system may be configured to erase signatures not frequently encountered such that, the next time the same television program is viewed, the signature of that segment of the program may have already been erased. Also, it is possible for news bulletins, public service announcements etc. to also be 15, 30 or 60 seconds long such that their signatures will be added to the database for future muting. Again, this is not a significant problem. Indeed, if the news bulletins, public service announcements etc. are broadcast frequently, the viewer may consider their subsequent muting to be quite advantageous.
As noted, a determination of whether a segment constitutes a commercial advertisement segment even though its signature does not match a stored signature is performed based upon the time periods separating event markers.
With further reference to
Thus, by detecting various event marker times, the system can determine whether a segment, which does not have a matching stored signature, is nevertheless a commercial advertisement segment. Hence, each received commercial advertisement is detected either immediately via a signature match or at the end of the segment via an event marker analysis. Once a commercial advertisement is detected, the system determines whether it represents the beginning of a new commercial advertisement group and, if so, muting is maintained for at least two minutes thereafter, regardless of whether the subsequent segments have matching signatures in the database. In one implementation, this is achieved as follows. For any detected commercial advertisement segment, if no other commercial advertisement segment preceded it during the previous 60 seconds, or some other predetermined minimum period of time, then the system identifies the detected commercial advertisement segment as being the first of a new group. If it were not the first of a new group, then a previous commercial advertisement segment of the same group would at least have terminated at some point during the preceding 60 seconds. (This assumes that no two consecutive commercial advertisement segments of a common group are ever separated by more than 60 seconds of non-commercial advertisement segments such as station breaks etc. In most cases, this assumption is correct.) Once the system identifies the first commercial advertisement of the group, muting is initiated and maintained for at least two minutes, or some other predetermined minimum group time period, from the beginning of that commercial advertisement. Notably, this determination is made regardless of whether the commercial advertisement was detected via signature match or event marker analysis. If detected by signature match, the determination is made during the reception of the commercial advertisement. If detected via event marker analysis, the determination is not made until the end of the segment. In either case, the duration of continuous muting is calculated based on the beginning of the first commercial advertisement segment of the group. As noted, muting is maintained for some predetermined period of time representative of the minimum duration of a group of commercial advertisements such as two-minutes. Any particular group may be longer in duration and continuous group-based muting may therefore end during the group. Signature-based muting, however, will continue for any remaining commercial advertisements of the group that have matching signatures in the database. Hence, the remaining advertisements of the group will not necessarily be un-muted. Other techniques for detecting the beginnings and predicting the endings of commercial advertisement groups may alternatively be employed.
Manual Addition of Signatures to Library
Instead of or in addition to the above-described process of automatically adding signatures of detected commercial advertisement segments to memory unit 128, a signature may be added by an operator command. While viewing a television broadcast, a commercial advertisement segment or other unwanted segment may be encountered that does not already have a stored signature and, therefore, is not muted. If the viewer wishes to have future airings of this unwanted segment muted, the viewer need only press an appropriate button or other control on the remote control unit for television set 100. The signature associated with the most recent event marker is then added to memory unit 128. Thereafter, a re-broadcast of the same segment will be detected and muted as previously described.
Methods of Operation
With reference to the remaining Figures, further details of exemplary and alternative method and apparatus embodiments of the invention will be described.
Steps 200-206 are repeatedly performed to search the television signal for additional event markers. Each newly detected event marker triggers a separate broadcast segment signature evaluation process for the broadcast segment beginning at that event marker. If part of the system performing the method of
Beginning at step 210, one broadcast segment evaluation process triggered at step 208 is set forth. Step 210 is shown connected to step 208 by a dashed line to indicate that the broadcast segment evaluation process proceeds independently of, and contemporaneously with, steps 200-206. At step 212, the signature corresponding to the current broadcast segment is read from the television signal. Additional details of step 212 are step forth in
At step 224, in addition to storing the signature for the current broadcast segment, the system also stores the length of the commercial advertisement and other pertinent information such as the latest date and time of day (date/time) of the broadcast of the segment. The length is used to determine how long to mute the output signal if the same commercial advertisement is again encountered. The latest date/time of broadcast can be employed to selectively erase signatures from the database based upon how recently the signatures had been encountered. More information regarding the content and purpose of information stored in the database along with the signature will be described in greater detail below. After the database is updated at step 224, step 225 is performed to determine whether the detected commercial advertisement is the first of a group and if so continuous group-based muting, described above, is performed until at least the end of the minimum pre-determined group time period, assuming no user over-ride. Then, step 222 is executed to end the current broadcast segment evaluation process.
Hence steps beginning at step 218 are performed only if the signature of the current broadcast segment does not match any in the database as determined at step 216. If there is a signature match at step 216 indicating that the current broadcast segment is a commercial advertisement, the system first determines whether the commercial advertisement is the first of a group, step 226, and then begins muting the output television signal, step 227, by using a mute control signal in the manner described above with reference to
With reference to
As noted, step 212 of
Hence, a bit string signature is evaluated based upon the average luminance level of selected lines of one selected frame following the event marker. Any bit string of suitable length may be employed. If too few test signature lines are selected yielding a short bit string, the bit string may not have sufficient bits to uniquely identify the broadcast segment. Accordingly, it is preferred that at least 32 signature test lines are selected yielding a bit string of at least 32 bits. With 32 bits, it is reasonably unlikely that test frames from different program segments will have the same bit string and hence, the bit string can be used to uniquely identify each unique broadcast segment. Also, a test frame occurring fairly promptly after the event marker should be selected. If a test frame is selected that occurs too late after the event marker, the system will not be able to promptly determine whether the signature of the test frame matches any of the recorded signatures and will therefore not be able to promptly begin real-time muting. Hence, it is preferred that the test frame occur no longer than about one second after the event marker. In alternative implementations, signature test lines may be drawn from two or more separate test frames.
If the television signal is digital, average luminance levels need not be employed. Rather, the signature may be simply based on selected bits within one or more selected digital frames. Skew and other related problems are also avoided or more easily overcome.
As noted, step 218 of
In the manual mode, the segment length can be determined in one of two ways. First, in a purely manual mode, the operator may designate the end of the segment with another command. The interval between the corresponding event markers preceding each of the two commands is then stored as the length of the segment. This is particularly useful for designating segments that do not have standardized lengths. Secondly, event markers may be processed as in the automatic mode, which is described next. In this case, the manual designation command is treated as a flag to ensure that a segment is classified as a commercial advertisement. Returning to step 251, if the automatic mode is enabled, the process proceeds to step 253 where a set of predetermined time periods based on standard commercial advertisement lengths are read from a memory. Examples include 15 seconds, 30 seconds, 60 seconds. At step 254, the system sets appropriate timers to begin waiting each of the pre-determined time periods. At step 256, the system determines whether a second event marker occurs at any of the pre-determined time periods following the first event marker. For example, the system first waits 15 seconds from the time of the first event marker and detects whether the television signal includes an event marker at that point in time. If not, the system waits until 30 seconds from the first event marker and so on. If a second event marker is detected at any of the predetermined times, step 258, then step 260 is performed wherein the broadcast segment beginning at the first event marker is identified as a commercial advertisement. At step 262, the system determines the length of the commercial advertisement by comparing the time the second event marker was detected with that of the first marker. Execution thereafter returns through step 264 to step 218 of
Step 224 of
As another example, the system may overwrite whichever signature simply has the least number of encountered broadcasts as represented by the number of broadcasts counter. To ensure that newly stored signatures are not immediately overwritten, the system may also look at the earliest time of broadcast and overwrite a signature only if it was recorded some minimum amount of time earlier.
If the system is configured to search for commercial advertisements even while the television set is not otherwise in use, the system may be configured to overwrite signatures encountered during times that the television was not otherwise in use first before overwriting signatures encountered while the television set was in use. This has the advantage of eliminating signatures that correspond to commercial advertisements not ordinarily encountered while the viewer of the television set typically watches television. In this regard, whenever a signature is first encountered, the system simply determines whether the television set is on and if so, sets the in-use bit to 1 if the set is on and 0 otherwise. Thereafter, if the signature is encountered while the in-use bit is set to 0 and while the television set is on, the in-use bit is re-set to 1. Once the in-use bit is set to 1 it is not reset to 0 until the record is erased. Hence, the in-use bit indicates whether the signature has been encountered at least once while the television set was on. In any case, if a signature record needs to be overwritten, records having in-use bits set to 0 are overwritten first before any records having in-use bits is set to 1.
In yet another example, the system may overwrite whichever entry was first written to the database as indicated by the first date/time of broadcast information. If such is the case, the memory is preferably implemented, as illustrated in
In yet another implementation, illustrated in
As noted above, in one implementation the system is configured to operate in a background mode to detect commercial advertisements and record the corresponding signatures even while the television set is not otherwise in use. This is provided in part to allow the system to quickly build a database of commercial advertisement signatures such that, when the television set is in use, there is a higher probability that commercial advertisements encountered will be muted. The background mode is particularly advantageous for use when the system is initially activated with few, if any, pre-stored signatures.
If at step 302, the database is not complete, either because the system is newly installed and has not yet built up a complete database or because the user has cleared the database, execution proceeds to step 322 where the system determines whether the user has activated the television monitor and if so execution proceeds to step 306 and following for non-background commercial advertisement detection processing as already described. If the user has activated the television monitor, execution instead proceeds immediately to step 324 where background processing begins. (It should be noted that step 322 differs from step 304 where the system waits for the user to activate the television monitor. With step 322, the system does not wait for the user to activate the television monitor but immediately triggers either background or non-background processing.)
Background processing begins at step 324 wherein broadcast signals are received. As with the basic method of
If the database remains incomplete and the television monitor remains deactivated, the background processing mode of steps 302-330 is performed in a loop to build a signature database. In this regard, every time a broadcast segment evaluation process is triggered at step 328 which detects a commercial advertisement, the signature for the advertisement is added to the database in the manner described above with reference to
As noted, a system employing the above-described techniques may be implemented either as a plug-in module or as an external device. If a plug-in module, the module is interconnected between an output of a tuner portion of the television set and an input to an audio/video display portion of the television set to output selectively muted or otherwise altered audio and video signals. If external, the system may be interconnected to a television set as shown in
A selective muting unit 400 is connected to audio 402 and video 404 output jacks of a television set 406. The audio and video output jacks are connected internally to a tuner portion (not separately shown) of the television set. Selective muting unit 400 receives the audio and video signals from the tuner via the audio and video output jacks and determines, using the techniques described above, when to initiate and terminate muting. An infrared muting transmitter 408 receives an electrical muting signal from muting unit 400 and outputs an infrared signal to an infrared input 410 of the television set. The infrared muting signal is set to emulate the infrared signal normally received by the television set from an infrared remote control unit (not separately shown) when a user presses a mute button on the remote control. In this manner, the audio is muted during detected commercial advertisements or other unwanted broadcast material as described above. The mute signal is transmitted at the beginning of a detected commercial advertisement and a second un-mute signal is transmitted either at the end of the commercial advertisement or at the end of a group of commercial advertisements.
If the television set is provided with a video mute capability triggered by a video mute infrared signal from a remote control unit, then infrared muting transmitter 408 additionally transmits the video mute signal to thereby provide both video and audio muting. Other television functions responsive to infrared input control may be additionally or alternatively exploited. Also, if the television set is provided with audio and video input jacks along with the audio and video output jacks, muting unit 400 may be configured to output muted audio and video signals into the audio and video input jacks of the television set. In such an embodiment, the television set is set to a mode for outputting signals received via the tuner of the television set through the audio and video output jacks and for displaying signals received through the audio and video input jacks. Hence, selectively muted television signals are display in the same manner as if the muting unit were mounted internally within the television set.
Thus far, the invention has been described with respect to exemplary embodiments employing television sets.
PCTV 500 is provided with hardware or software or both (not separately shown) for selectively muting the audio and video of television signals while operating in television mode in the same manner as described above. Hence, commercial advertisements or other unwanted broadcast material are selectively muted. When implemented via hardware, a plug-in module as described above is provided. The plug-in module either has its own memory for storing signatures and other information or is configured to employ a disk drive or other storage unit 512 of the PCTV for such purposes. Signatures may be stored temporarily during processing with a RAM (not shown) of the PCTV to expedite processing. If implemented in software, the software may, for example, run on a microprocessor of the PCTV to process digitized portions of the television signal (provided by an analog to digital converter not separately shown) for muting purposes, again using a disk drive or other storage unit 512 for storing signatures and the like. If the PCTV is configured to receive digitized television signals, then no tuner or analog to digital converter may be needed.
When in PC mode, the PCTV does not operate to perform any muting, unless the PC simultaneously displays the television signals within a window of monitor 506. Principles of the invention may be additionally applied to detect and selectively process other types of incoming data signals besides television signals to mute or otherwise alter unwanted portions of the signals, including signals otherwise processed only in PC mode including, for example, advertisement portions of input web pages.
What has been described are methods and apparatus for detecting commercial advertisements in real-time by comparing signatures of received broadcast segments with a database of stored signatures corresponding to known commercial advertisements. Segments having a signature matching any of the stored signatures may be muted or otherwise altered. For segments having signatures not found in the database, the system may nevertheless determine whether the segment is a commercial advertisement and, if so, add the signature to the database. This latter determination may be based upon known characteristics of commercial advertisements. In one exemplary embodiment, the determination is based upon the assumption that commercial advertisements are always preceded and followed by black frame/low audio event markers and are always 15, 30 or 60 seconds in length. This appears to be a fairly universal rule at least with television signals broadcast in the United States. However, if employed in connection with a television broadcast system wherein commercial advertisements are typically of different lengths, the system of the invention may be pre-programmed with those different lengths. In other implementations, other appropriate rules or characteristics of commercial advertisements or other selected segments may employed either additionally or alternatively for distinguishing the selected segments from other broadcast segments.
In general, almost any set of rules or characteristics of broadcast signals that serve to distinguish commercial advertisements or other selected segments from program segments may be employed to determine whether or not a broadcast segment, for which there is no signature match, is nevertheless a commercial advertisement. The rules are merely programmed or otherwise incorporated within system 108 of
Although described with reference to exemplary systems which operate to mute a television signal, almost any other desired action may alternatively be triggered. For example, the television set may completely cut off the broadcast video and audio feed and replace the video feed with, for example, a screen presenting an appropriate logo representative of the commercial determination system such as the tradename or trademark of the system. As another example, the television set may change the reception channel upon detection of a commercial advertisement then return to the same channel upon completion of the advertisement or group of advertisements. Such requires a two-tuner system, which is common for television sets with picture-in-picture (PIP) capability. Thus, when a commercial advertisement or other unwanted segment is detected, the television set will display the signal from an alternate channel, which may be specified by the viewer. The signal for the primary channel may be displayed in a PIP window, if desired, so that the viewer can monitor the signal in the event that the desired program resumes before the expected end of the unwanted segment. Upon return to the primary channel, the PIP window is removed or, if desired, the PIP window may then display the alternate channel.
Also, as described above, the system may merely record the date and time of each commercial advertisement for broadcast verification purposes. As can be appreciated, a wide range of alternative implementations are available consistent with the general principles of the invention.
The preceding description of exemplary embodiments is provided to enable any person skilled in the art to make or use the invention. It should be appreciated that not all components necessary for a complete implementation of a practical system are illustrated or described in detail. Rather, only those components necessary for a thorough understanding of the invention have been illustrated and described. Furthermore, it should be understood that the exemplary embodiments of the invention described herein are merely illustrative of general principles of the invention which can be applied to other applications, to achieve other ends, and to remedy other problems not specified herein. Accordingly, the scope of the invention should not be limited to the exemplary embodiments described herein
1. A method of operating a television receiver comprising:
- receiving a television signal in a television receiver;
- detecting a first event in the television signal;
- capturing a signature associated with a first segment of the television signal following the first event;
- comparing the captured signature to stored signatures;
- if the captured signature matches one of the stored signatures, controlling the television receiver to alter a display of the television signal;
- if the captured signature does not match any of the stored signatures, storing the captured signature in a temporary storage location;
- adding the captured signature to the stored signatures if a second event in the television signal is detected within a predetermined window of time following the first event.
2. The method of claim 1 wherein controlling the television receiver to alter the display of the television signal comprises muting an audio portion of the television signal.
3. The method of claim 1 wherein controlling the television receiver to alter the display of the television signal comprises muting a video portion of the television signal.
4. The method of claim 1 wherein controlling the television receiver to alter the display of the television comprises providing an alternate video signal to replace the received television signal.
5. The method of claim 4 wherein the received television signal is displayed in a window within a display of the alternate video signal.
6. The method of claim 1 wherein at least some of the stored signatures are stored in response to a user request.
7. A method of operating a television receiver comprising:
- receiving a television signal in a television receiver;
- detecting a first event in the television signal;
- capturing a signature associated with a first segment of the television signal following the first event;
- comparing the captured signature to stored signatures;
- if the captured signature matches one of the stored signatures, controlling the television to alter a display of the television signal;
- if the captured signature does not match any of the stored signatures, storing the captured signature in a temporary storage location;
- monitoring a signal receiver for a user input signal;
- adding the captured signature to the stored signatures if the user input signal is received prior to detection of a next event in the television signal.
8. The method of claim 7 wherein controlling the television receiver to alter the display of the television signal comprises muting an audio portion of the television signal.
9. The method of claim 7 wherein controlling the television receiver to alter the display of the television signal comprises muting a video portion of the television signal.
10. The method of claim 7 wherein controlling the television receiver to alter the display of the television comprises providing an alternate video signal to replace the received television signal.
11. The method of claim 10 wherein the received television signal is displayed in a window within a display of the alternate video signal.
12. A television set comprising:
- a television signal receiver;
- means for detecting a first event in the television signal;
- means for capturing a signature associated with a first segment of the television signal following the first event;
- means for comparing the captured signature to stored signatures;
- means for altering the display of the television signal if the captured signature matches one of the stored signatures;
- means for storing the captured signature in a temporary storage location if the captured signature does not match any of the stored signatures;
- means for adding the captured signature to the stored signatures if a second event in the television signal is detected within a predetermined window of time following the first event.
13. The television set of claim 12 wherein the means for altering the display of the television signal comprises means for muting an audio portion of the television signal.
14. The television set of claim 12 wherein the means for altering the display of the television signal comprises means for muting a video portion of the television signal.
15. The television set of claim 12 wherein the means for altering the display of the television signal comprises means for replacing the received television signal with an alternate video signal.
16. The television set of claim 15 further comprising a picture-in-picture processor to display the received television signal in a window within a display of the alternate video signal.
17. The television set of claim 12 further comprising a manually-operated user control to store at least some of the stored signatures.
Filed: Aug 2, 2004
Publication Date: Jan 20, 2005
Inventor: Jerry Iggulden (Los Angeles, CA)
Application Number: 10/910,128