Classifications

• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
  • H04N7/00—Television systems
  • H04N7/01—Conversion of standards, e.g. involving analogue television standards or digital television standards processed at pixel level
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
  • H04N7/00—Television systems
  • H04N7/01—Conversion of standards, e.g. involving analogue television standards or digital television standards processed at pixel level
  • H04N7/0117—Conversion of standards, e.g. involving analogue television standards or digital television standards processed at pixel level involving conversion of the spatial resolution of the incoming video signal
  • H04N7/012—Conversion between an interlaced and a progressive signal

Definitions

• the invention relates to a method and device for de-interlacing image signals, and to a display apparatus comprising such a de-interlacing device.
• De-interlacing is a basic requirement for practically all video scanning format conversions. Since perfection under all circumstances is impossible to achieve, many different algorithms have been proposed, ranging from simple spatial de-interlacing methods to the advanced motion compensated (MC) ones.
• MC motion compensated
• the invention provides a de-interlacing method and device, as well as a display apparatus, as defined in the independent claims.
• Advantageous embodiments are defined in the dependent claims.
• a method of de-interlacing video data in accordance with a primary aspect of the present invention, at least three different de-interlacing algorithms are applied on the video data to obtain at least three de-interlaced signals, no majority of de-interlacing algorithms copying a single spatio-temporally neighboring pixel to the interpolated position, and the at least three de-interlaced signals are order statistical filtered to obtain an output signal.
• Fig. 1 illustrates the aperture of a three field de-interlacer
• Fig. 2 shows a general architecture of the method according to the invention.
• Fig. 3 shows a preferred embodiment of a display apparatus comprising a de- interlacing circuit in accordance with the present invention.
• the current invention provides the required robust alternative.
• the current invention uses a set of (simple) de-interlacing algorithms, which is chosen such that a majority of the algorithms has a certain strength, e.g. robustness, another majority has a strength in e.g. edge preservation, and a third majority is strong in e.g. detail preservation.
• a majority of the algorithms has a certain strength, e.g. robustness, another majority has a strength in e.g. edge preservation, and a third majority is strong in e.g. detail preservation.
• the output of a median filter that selects between these alternatives is, simply because the majority wins.
• Unique in this new design is the fact that motion vectors can be applied to improve its performance, even if the reliability of these vectors is very poor. In case no vectors are being used, the method outperforms all known non-motion compensated methods. Next generation Trimedia will be designed to support this algorithm.
• the output of the de-interlacer is defined by:
• Fig. 1 illustrates the aperture of a three field de-interlacer.
• the vertical position VP is indicated on the vertical axis, while the field number FN is indicated on the horizontal axis.
• the black dots A-D indicate original samples, while the open circle E indicates an interpolated sample to be obtained in accordance with the lower expressions in formulae 1, 6 or 7.
• the median filter operator MED(A, B, C) is defined by:
• the output of the vertical -temporal filter F VT is defined by:
• the Max(x) operator determines the maximum value of the variable x.
• the vertical-temporal filter was defined by:
• FIG. 3 A possible architecture of this invention is presented in Fig. 3.
• the output of the VT median is likely to be equal to the sample F(x, n - ⁇ ) , and therefore, either of the two is selected as the output.
• the VT median introduces alias by resulting in either E(3c - u ⁇ , ⁇ )or F(x + u ⁇ ,n) .
• the output of the linear vertical -temporal filter, E ⁇ (x, n) will resemble E(x, n + 1) . Therefore, either of these two samples is selected as the output sample, preserving vertical detail.
• the main difference can be observed for vertical moving objects containing vertical detail.
• the proposed de-interlacing algorithm is an order statistical filter with multiple inputs from different de-interlacing methods as shown in Fig. 2.
• Fig. 2 shows a general architecture of the method according to the invention.
• An ordered statistical filter OSF supplies an interpolated line Fo based on n different de-interlaced outputs DIO- 1 , DIO-2, ... , DIO-n obtained by n different de-interlacing methods.
• the de-interlacing methods need not be all different.
• a majority of the de- interlacing methods is strong on a first quality aspect (e.g. edge preservation).
• Another majority is strong on a second quality aspect (e.g. detail preservation), and so on. Since the order statistical filter selects the input belonging to the overall majority, the resulting de- interlacing algorithm combines the strengths of the input algorithms.
• Fig. 3 shows a preferred embodiment of a display apparatus comprising a de- interlacing circuit in accordance with the present invention.
• An input image signal F is applied to a first field memory FM1, an output of which is coupled to a second field memory FM2.
• Inputs of cache memories CMl, CM2 and CM3 are connected to the input of the field memory FM1 and to the outputs of the field memories FM1 and FM2, respectively.
• the cache memory CMl supplies the sample A from field n+1 to a first median filter MEDl, while the cache memory CM2 supplies the samples B and C to the first median filter MEDl .
• Outputs of the cache memories CMl and CM2 are coupled to respective inputs of a vertical-temporal filter VTF.
• a second median filter MED2 receives the sample D from field n-1 from the cache memory CM3, the median of A, B and C from the first median filter MEDl, and a filter output F VT from the vertical-temporal filter FVT, to supply the interpolated line E.
• the cache memory CM2 outputs the original line F.
• An insertion circuit IC inserts the interpolated lines E between the original lines F to obtain a display signal Fo that is displayed by a display device DD.
• De- interlacing is the process required to convert interlaced video into a progressive format.
• Many algorithms including high performance motion compensated methods and low cost solutions are available from the literature.
• a set of simple de-interlacing algorithms is used, which is chosen in such a manner, that a majority of the algorithms is robust, another majority is good in edge preservation, and a third majority is strong in detail preservation.
• the output of a median filter that selects between these alternatives is, simply because the majority wins.
• Unique in this new design is the fact that motion vectors can be applied to improve its performance, even if the reliability of these vectors is very poor. In case no vectors are being used the method outperforms all known non- motion compensated methods.
• Preferred aspects of the invention provide a method, and an apparatus realizing this method, for de-interlacing video data, characterized in that the interpolated pixels are calculated with an order statistical filter using at its input the N outputs of a number of N de- interlacers, where different majorities of these algorithms share individual strengths, and there exist no majority of de-interlacing algorithms that copy a single spatio-temporally neighboring pixel to the interpolated position.
• N 3
• the order statistical filter has the following inputs: the output of a first de-interlacing algorithm that is strong on a first and a second criterion (e.g. robustness and edge preservation), but weak on a third criterion (e.g.
• the order statistical filter is a median filter.
• the first de-interlacing algorithm is a vertical-temporal median filter.
• the third de-interlacing algorithm is a (motion compensated) field insertion, inserting either a pixel from the previous or from the next input video field.
• the second de-interlacing algorithm is a linear vertical-temporal filter.

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• Engineering & Computer Science (AREA)
• Computer Graphics (AREA)
• Multimedia (AREA)
• Signal Processing (AREA)
• Television Systems (AREA)

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• 2000
  • 2000-05-04 WO PCT/EP2000/004305 patent/WO2000072585A1/en not_active Ceased
  • 2000-05-04 DE DE60040517T patent/DE60040517D1/de not_active Expired - Lifetime
  • 2000-05-04 EP EP00931204A patent/EP1101354B1/en not_active Expired - Lifetime
  • 2000-05-04 JP JP2000619924A patent/JP2003500944A/ja active Pending
  • 2000-05-04 KR KR1020017001114A patent/KR100731523B1/ko not_active Expired - Fee Related
  • 2000-05-04 CN CNB008009384A patent/CN1157053C/zh not_active Expired - Fee Related
  • 2000-05-22 US US09/575,604 patent/US6618094B1/en not_active Expired - Lifetime

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