CN1282362C - Detecting method for 3:2 pull down film source - Google Patents

Abstract

The present invention relates to a detecting method for a 3: 2 pull down film source. Firstly, a source is received, and the field difference of two fields of the same type in the source is calculated; then, the mean field difference is calculated according to the field difference of at least one corresponding previous field in the source; and subsequently, whether a 3: 2 pull down identification mark exists in the source is detected according to the field difference and the mean field difference. In addition, broken editing points in the source are detected according to staggered vision lattice information of the source.

Description

The method for detecting in the film of leaving behind at 3: 2 source

Technical field

The invention relates to a kind of film source (Film Source) method for detecting, and be particularly to a kind ofly can consider that the difference between two fields (Field) and staggered (Interlaced) look the method for detecting in 3: 2 (3: 2 Pull-Down) films sources of leaving behind of lattice (Frame) information.

Background technology

On the practice, the dynamic picture sequence can rough classification be film source and video recording (Video) source.Film source to look the lattice speed of looking that lattice speed (Frame Rate) looks lattice NTSC video recording source for 24 of per seconds be that 30 of per seconds are looked lattice or 60 fields.Therefore, in order in the ntsc television system, to show film, the looking lattice speed and must be converted to 30 of film by 24.This looks lattice rate transition (or 2: the 3) program of leaving behind that is commonly referred to 3: 2.

Fig. 1 shows that one is applied to and has four 3: 2 program examples of leaving behind looking the vidclip of lattice (A, B, C and D).In this example, original film is looked lattice and is divided into three or two interlaced fields.Promptly look lattice A and see through and to duplicate it and be divided into three fields, and look lattice B and look lattice D and only be divided into two fields with looking lattice C.Therefore, look lattice speed by being looked 60 fields of per second that lattice are converted to the interlaced field sequence, and be converted to staggered 30 of per seconds looking the lattice sequence afterwards and look lattice by 24 of the per seconds of original film sequence.

Because being applicable on NTSC alternating expression TV, 3: 2 film sequence of leaving behind play, when the film sequence of leaving behind at 3: 2 is play on (Progressive) (scanning) TV or computer screen in proper order, looking the staggered lattice of looking that lattice merge by different films, as looking lattice " A+B " and looking some irritating irregularity situations of meeting existence in the lattice " B+C " among Fig. 1, as pectination lines noise (Comb Artifacts), jagged edges etc.In order to remove these unrestrained peaks processing, detect leaves behind film sequence and carry out anti-movie news (Inverse Telecine) program at 3: 2 left behind that to look lattice be very important for film that film sequence restores back and forth in so far 3: 2.Therefore, when using in different devices, leave behind at 3: 2 film sequence or interlace video sequence of identification and detecting is very important.

In addition, the reason of duplicating owing to the interlaced field film sequence of leaving behind at 3: 2 has a unique distinguishing mark (Signature).This distinguishing mark is shown in Fig. 2 and is illustrated in down.The fragment of this interlaced field sequence comprises 3: 2 leave behind film source.When same type (as, upper end (Top) or lower end (Bottom)) interlaced field when comparing, its comparison result is " 10000100001... ", wherein 1 expression comparison is consistent (Match), 0 representative comparison is inconsistent.Therefore, the detecting of leaving behind at 3: 2 between film sequence or interlace video sequence can be finished by the field of alternately comparing same type and the distinguishing mark of seeking in sequence " 10000100001... ".

Fig. 3 shows the method for detecting in known 3: the 2 film sources of leaving behind.With reference to figure 2 and Fig. 3, be illustrated in down simultaneously.At first, index (Field Index) n, pairing counter (Match Counter), be made as 0 (step S301) with mode counter (Mode Counter).Pairing counter is detected in order to record the how many times distinguishing mark " 10000 " of leaving behind at 3: 2, and mode counter is used to refer to whether 3: 2 distinguishing marks of leaving behind are correct.These two counters are 3: 2 crucial indicating devices of film source detecting of leaving behind, and will describe in more detail in following.

Then, as step S302, receive two have the field of same type and compare they whether because duplicate former thereby identical.This comparison is to see through calculated field poor (FieldDifference) FieldDiff to finish (S303), and its formula is as follows:

$\mathrm{FieldDiff}=\underset{y=0}{\overset{M-1}{\mathrm{\Σ}}}\underset{x=0}{\overset{N-1}{\mathrm{\Σ}}}|F(x,y,n)-F(x,y,n+2)|,$

Wherein, M and N are respectively the Gao Yukuan of field.If a difference is less than a threshold value Fi_th (step S304 is), as step S305, these two fields are considered as that comparison is consistent, pairing counter increase by 1 and mode counter be clearly 0 to represent the beginning of distinguishing mark " 10000 ".Otherwise greater than threshold value Fi_th (step S304 denys), as step S306, the inconsistent and mode counter increase by 1 of comparison is looked in these two fields as if a difference.

Afterwards, come the pattern of source sequence to judge according to the value of pairing counter that in Fig. 2, shows and mode counter.When pairing counter greater than 1 and mode counter when equaling 0 (step S307 is), as step S308, flag (Flag)-film mode (FilmMode) is set as 1 and represents 1: 2 film sequence of leaving behind detect.Otherwise the value of mode counter can be used for judging whether that sequence meets distinguishing mark " 10000 ".If mode counter is less than or equal to 4 (step S309 denys), represent film mode not change (step S310).Yet, if mode counter is greater than 4 (step S309 is), represent that this sequence has no longer met 3: 2 and leave behind distinguishing mark " 10000 ", as step S311, film mode is set as 0 and represents that this sequence is not one 3: 2 film sequence of leaving behind.

In order to prevent overflow (Overflow), when mode counter surpasses a set maximum (step S312 is), as step S313, mode counter is set as this maximum.This handles flow process along with the input of sequence repeats dynamically to monitor 3: 2 distinguishing marks of leaving behind (step S315 and get back to step S302) up to EOS (step S314 is) always.

Yet prior art method has two shortcomings: the first, and owing to digital recording compression and processing cause information loss, perhaps the field difference between the duplicate field can surpass threshold value Fi_th.Therefore, only utilize a difference to judge that with threshold value whether duplicate field is consistent is accurate inadequately.The second, the detecting of bad in-edit (Bad Editing Point) is not have efficient.For instance, in Fig. 4,3: 2 sequences of leaving behind comprise good and bad in-edit.Because good in-edit is to observe the order of leaving behind at 3: 2, therefore, distinguishing mark " 10000 " is still to keep.Otherwise if bad in-edit is violated the order of leaving behind at 3: 2, distinguishing mark will can not observed " 10000 " again.Yet so bad in-edit will just can be detected above 4 o'clock up to mode counter.Therefore, at bad in-edit and the dump movie between the point when detecting bad editor look lattice will be used anti-movie news program and rebuild mistakenly.Promptly there are two to look lattice, cause serious reconstruction errors by field " H " that merges and " I " reconstruction.

Summary of the invention

In view of this, the method for detecting of main purpose of the present invention for providing difference and staggered 3: 2 of looking lattice information between a kind of field that can consider two comparisons to leave behind the films source.

Another object of the present invention is to utilize and check the staggered detecting validity that lattice information is improved bad in-edit of looking.

In order to reach above-mentioned purpose of the present invention, the method for detecting in the film of can leaving behind by 3: 2 provided by the present invention source is reached.

Method for detecting according to 3: 2 films of leaving behind of the embodiment of the invention are originated at first, receive a source, and coefficient correlation is initially set zero.Coefficient comprise an index n, pairing counter, mode counter, accumulation (Accumulated) difference accDiff, with mean field difference aveDiff.

Then, calculate two field difference FieldDiff with field of same type, and with field difference FieldDiff and one first threshold value Fi_th and change (Adaptive) threshold value Adap_th.If a difference is less than Fi_th and Adap_th, pairing counter increases by 1 and mode counter, accDiff, be made as 0 with aveDiff.Otherwise if a difference is not less than Fi_th or Adap_th, mode counter increases by 1, FieldDiff adds to accDiff and aveDiff equals accDiff divided by mode counter.Wherein, Adap_th equals aveDiff and is multiplied by a COEFFICIENT K.

At last, when pairing counter greater than 1 and mode counter when equaling 0, the source is detected as 3: the 2 film source of leaving behind, and when pairing counter greater than 4 the time, the source is detected as non-3: 2, and the film of leaving behind is originated.

In addition, when mode counter equal 3 and mode counter equal one of the corresponding interlaced field in 3 places look lattice meet 3: 2 film sources of leaving behind in proper order with the interlaced field order time, a bad in-edit is detected in the source.In other words, promptly when interlaced field is the field, lower end, judge that whether this looks lattice is one staggeredly to look lattice, and when interlaced field is the field, upper end, judge that whether this looks lattice is one to look lattice in proper order.

In addition, when the associative mode counter equals 3 field when the field, lower end, if the associative mode counter equals 3 and 4 two in proper order respectively, then a bad in-edit is detected in the source.

Description of drawings

Fig. 1 shows that one is applied to and has four 3: 2 program examples of leaving behind looking the vidclip of lattice (A, B, C and D);

Fig. 2 shows 1: 2 leave behind film source and its distinguishing marks;

Fig. 3 is that a flow chart is the method for detecting that shows known 3: the 2 film sources of leaving behind;

Fig. 4 shows 3: 2 sequences of leaving behind having good and a bad in-edit respectively;

Fig. 5 is that a flow chart is the operating process that shows the method for detecting of originating according to 3: 2 films of leaving behind of the embodiment of the invention;

Fig. 6 shows a bad in-edit detecting example according to the embodiment of the invention.

The figure number explanation:

A, B, C, D, E, A+B, B+C-look lattice;

N-field index;

The FieldDiff-field is poor;

AccDiff-accumulation field is poor;

The aveDiff-mean field is poor;

The Fi_th-threshold value;

Adap_th-changes threshold value;

The K-coefficient;

S301, S302 ..., the S315-operating procedure;

S501, S502 ..., the S517-operating procedure.

Embodiment

The present invention roughly makes the threshold value Fi_th of use difference FieldDiff and known use judge whether that duplicate field is found.Yet the present invention also utilizes a temporary transient local threshold value to decide that a poor FieldDiff is whether enough to judge that two comparisons match for a short time.Above-mentioned based on be assumed to be and no matter compress or handle cause wrong much in film sequence, the difference between two duplicate field always can be less than other unmatched two.Yet because difference is the content that is relevant to strongly in the film sequence, the limiting field difference compares with a temporary transient local vidclip will be more accurate.Therefore, in the present invention, an extra threshold value can by the front court difference comparison result and dynamically upgrade.

In addition, the invention provides by detecting with reference to the staggered bad in-edit of looking lattice information.The above-mentioned actual conditions that are based on the film order of leaving behind at 3: 2, the staggered lattice of looking that merge in leave behind film sequence at 3: 2 have another unique distinguishing mark " PIIPP ", wherein " P " expression in proper order and " I " expression staggered.In other words, one group of staggered looking in the lattice of leaving behind at 3: 2, first looks lattice in proper order, and second and the 3rd is looked lattice is to interlock, and latter two looks lattice in proper order.This distinguishing mark can be known in the example of Fig. 1 and learns.Therefore, if the staggered lattice of looking in the film order of leaving behind at 3: 2 are not observed this distinguishing mark, then necessarily there is bad in-edit in this source, and takes place for fear of reconstruction errors, the also not all right execution of the anti-movie news program video display lattice of sending a telegram in reply back and forth.

Fig. 5 shows the operating process according to the method for detecting in 3: 2 film sources of leaving behind of the embodiment of the invention.At first, as step S501, receive a source, and as step S502, the coefficient correlation that uses in the detecting is initially set zero.These coefficients comprise an index n, pairing counter, mode counter, accumulation field difference accDiff, with mean field difference aveDiff.Similarly, pairing counter is to be used for recording the how many times distinguishing mark " 10000 " of leaving behind at 3: 2 to be detected in the source, and mode counter is used to refer to whether 3: 2 distinguishing marks of leaving behind are correct.

Then, as step S503, two fields (F (n) and F (n+2)) with same type are received, and as step S504, calculate F (n) and the poor FieldDiff in the field of F (n+2).Similarly, the formula of a difference is as follows:

$\mathrm{FieldDiff}=\underset{y=0}{\overset{M-1}{\mathrm{\Σ}}}\underset{x=0}{\overset{N-1}{\mathrm{\Σ}}}|F(x,y,n)-F(x,y,n+2)|,$

Wherein, M and N are respectively the Gao Yukuan of field.Afterwards, as step S505, field difference FieldDiff and two threshold values are compared.First threshold value is Fi_th, its be defined in haply two be consistent the field between admissible maximum field poor.Second threshold value is a change threshold value Adap_th, and it is poor that its content and temporarily upgrading in the reference field sequence decides two maximums that are consistent to allow.In the present embodiment, Adap_th be the front field comparison mean field difference aveDiff some (Fraction) and be:

Adap_th＝aveDiff×K

Wherein, K is the real number at 0 to 1, and aveDiff is:

aveDiff＝accDiff/ModeCounter。

If have the content of high activity in being assumed to be of this sequence on the scene, the mean field difference will be than higher, and in the same manner, a poor accDiff that adds up also can be than higher.Therefore, admissible difference will be than higher between duplicate field.Yet if having the content of low activity in the sequence on the scene, the mean field difference will be lower, and in the same manner, a poor accDiff that adds up also can be lower.Therefore, admissible difference will be lower between duplicate field.It should be noted that threshold value Adap_th should than Fi_th come little, and Fi_th and K can decide according to different application or film types, and normally learn with experience.

If present field difference FieldDiff is less than Fi_th and Adap_th (step S505 is), a F (n) is considered to be consistent with a F (n+2) and a F (n+2) is the duplicate field of F (n).Afterwards, as step S506, pairing counter increases by 1 and mode counter, accDiff, be made as 0 with aveDiff.Otherwise, if a difference is not less than Fi_th or Adap_th (step S505 denys), F (n) does not meet with a F (n+2) on the spot, then as step S507, mode counter increases by 1, FieldDiff adds to accDiff, aveDiff and equals accDiff divided by mode counter, and Adap_th equals aveDiff and is multiplied by COEFFICIENT K.

Afterwards, come the pattern of source sequence can be according to judging as the pairing counter that shows among Fig. 2 and the value of mode counter.When pairing counter greater than 1 and mode counter when equaling 0 (step S508 is), as step S509, flag-film mode (FilmMode) is set as 1 and represents 1: 2 film sequence of leaving behind detect.Otherwise the value of mode counter is used to judge whether this sequence observes distinguishing mark " 10000 ".If pairing counter was greater than 4 o'clock (step S510 was), this sequence is no longer observed 3: 2 distinguishing marks of leaving behind " 10000 ", and as step S511, film mode is set as 0 and represents that this sequence is not one 3: 2 film sequence of leaving behind.Yet, if pairing counter little with or equal at 4 o'clock (step S510 not), staggeredly look lattice information and be used to detect bad in-edit.This is staggered looks lattice information can to point out to look lattice is one in proper order or the staggered lattice of looking.The detail operations of bad in-edit detecting will be illustrated in down.

Fig. 6 shows the bad in-edit detecting example according to the embodiment of the invention.The checkpoint that is used for detecting bad in-edit in Fig. 6 is 3 interlaced field for the corresponding modes counter.In first checkpoint, interlaced field " B " is field, a lower end.Therefore, the staggered lattice " A+B " of looking according to 3: 2 its correspondences of order of leaving behind should all be the staggered lattice of looking with the next staggered lattice " B+C " of looking.Therefore, if one of them be not staggered look lattice then this checkpoint be a bad in-edit.Similarly, second checkpoint, interlaced field " D " is field, a upper end and should is to look lattice in proper order according to the staggered lattice " D " of looking of its correspondence of order of leaving behind at 3: 2.If look lattice " D " be not look in proper order lattice then this checkpoint be a bad in-edit.

At the corresponding modes counter is that the reason that 3 interlaced field is chosen as the checkpoint is can not be had bad in-edit in this generation if duplicate field can detect.Therefore, bad in-edit only can take place when mode counter is 3 or 4, and the preference pattern counter is 3 to be to be detecting ahead of time, but is not restricted to this.

If bad in-edit is not detected (step S512 is),, represent film mode not change as step S513.Yet if detect bad in-edit (step S512 not), as step S511, film mode is set as 0 and represents that this sequence is not one 3: 2 film sequence of leaving behind, and pairing counter is set as 0.

It should be noted that in the checkpoint 1 bad in-edit detecting can also by check the corresponding modes counter be 3 and 4 " B " and gradualness (Progressiveness) finish.Order is for correct if the result in proper order, was then left behind in these 3: 2, otherwise this checkpoint is a bad in-edit.

After film mode was judged and looked the bad in-edit detecting of lattice F (n), in order to prevent overflow, when mode counter surpasses a set maximum (step S514 is), as step S515, mode counter was set as maximum.In addition, local movable when reacting the station of movie contents in order to keep change threshold value Adap_th, accDiff and aveDiff are set as 0, and will recomputate (S517 and get back to S503) when next looks lattice (F (n+1)) when inspection.

This handles leave behind along with the input of sequence repeats dynamically to monitor 3: 2 always source and check that bad in-edit is up to EOS (step S516 is) of flow process.

Therefore, the method for detecting in the film of leaving behind by 3: 2 provided by the present invention source can consider that two differences between the field look lattice information whether detect the source be 3: 2 film sources of leaving behind with staggered.In addition, the present invention is by checking that the staggered lattice information of looking provides bad more accurately in-edit method for detecting in contingent place.

Claims (11)

1. the 3:2 method for detecting in film source of leaving behind comprises the following steps:

Receive a source;

Calculate a difference of two fields that have same type in this source;

According at least two differences in this source, it is poor to calculate a mean field; And

According to more next two field difference whether less than this mean field difference to produce comparative result, utilize this comparative result whether to have the 3:2 distinguishing mark of leaving behind to be present in this source with inspection.

2. the leave behind method for detecting in film source of 3:2 according to claim 1 more comprises according to one of this source and staggeredly looks lattice information and detect a bad in-edit.

3. the leave behind method for detecting in film source of 3:2 according to claim 2, wherein should staggered looking lattice information, to indicate the corresponding lattice of looking be one in proper order or the staggered lattice of looking.

4. the 3:2 method for detecting in film source of leaving behind comprises the following steps:

Receive a source;

Initial setting plural number coefficient is zero, this coefficient comprise an index n, a pairing counter, a mode counter, an accumulation difference accDiff, with a mean field difference aveDiff;

Calculate the poor FieldDiff of two field F (n) of having same type in this source and F (n+2);

This is differed from FieldDiff and one first threshold value Fi_th and a change threshold value Adap_th compares;

If FieldDiff is less than this Fi_th and this Adap_th for this difference, with this pairing counter increase by 1 and with this mode counter, this accDiff, and this aveDiff be made as 0;

If a difference is not less than this Fi_th or this Adap_th, this mode counter is increased by 1, this FieldDiff is added to this accDiff, this aveDiff equals this accDiff divided by this mode counter, and this Adap_th equals this aveDiff and is multiplied by a COEFFICIENT K; And

When this pairing counter greater than 1 and this mode counter when equaling 0, detect this source and be the 3:2 film source of leaving behind.

5. the leave behind method for detecting in film source of 3:2 according to claim 4, more comprise when this pairing counter greater than 4 the time, this source is detected as the non-3:2 film of leaving behind and originates.

6. the leave behind method for detecting in film source of 3:2 according to claim 4 more comprises by judgement comprising that mutually whether lattice are looked in a video recording that should mode counter equals 3 video recording field is one to look lattice in proper order or the staggered lattice of looking are detected leave behind bad in-edit in the film sequence of 3:2.

7. the leave behind method for detecting in film source of 3:2 according to claim 6, when this video recording be field, a lower end and this video recording to look lattice be not to be one to interlock when looking lattice, this bad in-edit is detected in this source.

8. the leave behind method for detecting in film source of 3:2 according to claim 6 is when this video recording is that adjacent after lattice are looked in field, a lower end and any one this video recording looked lattice and this to look lattice be not that this bad in-edit is detected in this source when looking lattice for interlocking.

9. the leave behind method for detecting in film source of 3:2 according to claim 6, when this video recording field be field, a upper end and this video recording to look lattice be not to be one when looking lattice in proper order, this bad in-edit is detected in this source.

10. the leave behind method for detecting in film source of 3:2 according to claim 4 more comprises by judging respectively mutually whether should mode counter be 3 and 4 two is the bad in-edit of detecting in proper order in this source.

The method for detecting in film source 11. 3:2 according to claim 10 is left behind, wherein to should mode counter be 3 this be field, a lower end.

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