EP1157557A1 - Procede et dispositif pour la transformation d'une zone d'image - Google Patents

Procede et dispositif pour la transformation d'une zone d'image

Info

Publication number
EP1157557A1
EP1157557A1 EP00906176A EP00906176A EP1157557A1 EP 1157557 A1 EP1157557 A1 EP 1157557A1 EP 00906176 A EP00906176 A EP 00906176A EP 00906176 A EP00906176 A EP 00906176A EP 1157557 A1 EP1157557 A1 EP 1157557A1
Authority
EP
European Patent Office
Prior art keywords
transformation
image area
horizontal
vertical
image
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP00906176A
Other languages
German (de)
English (en)
Inventor
Andre Kaup
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Siemens AG
Original Assignee
Siemens AG
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Siemens AG filed Critical Siemens AG
Publication of EP1157557A1 publication Critical patent/EP1157557A1/fr
Withdrawn legal-status Critical Current

Links

Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N19/00—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals
    • H04N19/60—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals using transform coding
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N19/00—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals
    • H04N19/10—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals using adaptive coding
    • H04N19/102—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals using adaptive coding characterised by the element, parameter or selection affected or controlled by the adaptive coding
    • H04N19/12—Selection from among a plurality of transforms or standards, e.g. selection between discrete cosine transform [DCT] and sub-band transform or selection between H.263 and H.264
    • H04N19/122—Selection of transform size, e.g. 8x8 or 2x4x8 DCT; Selection of sub-band transforms of varying structure or type
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N19/00—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals
    • H04N19/10—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals using adaptive coding
    • H04N19/134—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals using adaptive coding characterised by the element, parameter or criterion affecting or controlling the adaptive coding
    • H04N19/136—Incoming video signal characteristics or properties
    • H04N19/14—Coding unit complexity, e.g. amount of activity or edge presence estimation

Definitions

  • the invention relates to a method and an arrangement for transforming an image area
  • Such a method with an associated arrangement is known from [1].
  • the known method serves as a coding method in the MPEG standard and is essentially based on the hybrid DCT (Discrete Cosine Transformation) with motion compensation.
  • a similar procedure is used for video telephony with nx 64kbit / s (CCITT recommendation H.261), for TV contribution (CCR recommendation 723) with 34 or 45Mbit / s and for multimedia applications with 1.2Mbit / s s (ISO-MPEG-1) is used.
  • the hybrid DCT consists of a temporal processing stage, which takes advantage of the relationship between successive images, and a local processing stage, which uses correlation within an image.
  • the local processing essentially corresponds to the classic DCT coding.
  • the image is broken down into blocks of 8x8 pixels, each of which is transformed into the frequency domain using DCT.
  • the result is a matrix of 8x8 coefficients, which approximately reflect the two-dimensional spatial frequencies in the transformed image block.
  • a coefficient with frequency 0 (DC component) represents an average gray value of the image block.
  • a second step of data reduction takes the form of an adaptive quantization, by means of which the amplitude accuracy of the coefficients is further reduced or by which the small amplitudes are set to zero.
  • Quantization depends on the fill level of the output buffer: If the buffer is empty, fine quantization takes place, so that more data is generated, while if the buffer is full, it is coarser, which reduces the amount of data.
  • variable-length coding VLC
  • the time differences are only small, even if the movements in the picture are small. If, on the other hand, the movements in the picture are large, large differences arise, which in turn are difficult to code. For this reason, the picture-to-picture movement is measured (motion estimation) and compensated before the difference is formed (motion compensation).
  • the motion information is transmitted with the image information, usually only one motion vector per macro block (e.g. four 8x8 image blocks) is used.
  • the coder also has a temporal recursion loop, because the predictor must calculate the prediction value from the values of the (coded) images already transmitted.
  • An identical time recursion loop is in the decoder, so that the encoder and decoder are completely synchronized.
  • I-pictures No temporal prediction is used for the I-pictures, ie the picture values are transformed and encoded directly, as shown in picture 1. I-pictures are used to complete the decoding process without knowledge of the time
  • a temporal prediction is made on the basis of the P-pictures, the DCT is applied to the temporal prediction error.
  • B-pictures With the B-pictures the temporal bidirectional prediction error is calculated and then transformed.
  • the bidirectional prediction works basically adaptively, i.e. forward prediction, backward prediction or interpolation is permitted.
  • a picture sequence is divided into so-called GOPs (Group Of Pictures), n pictures between two I-pictures form a GOP.
  • the distance between the P-pictures is denoted by m, where there are m-1 B-pictures between the P-pictures.
  • the encoder or column-by-line transformation is preferred ...
  • the type of transformation is the same for all image data, which is disadvantageous for certain image data.
  • the object of the invention is to transform an image area, the order of vertical and horizontal transformation depends on predetermined conditions that are specifically taken into account.
  • a clear improvement in the image quality can be achieved.
  • a method for transforming an image area in which a decision unit first carries out a vertical transformation of the image area and then a horizontal transformation of the image area or vice versa, first the horizontal transformation and then the vertical transformation.
  • a further development consists in the fact that the image area has an irregular structure.
  • the order of the transformations can be determined depending on a predetermined or a determined value in the decision unit or on the decision unit.
  • the order of horizontal and vertical transformation can be predetermined by the decision unit in such a way that the best possible result is achieved with regard to the compression of the image area.
  • the order of the transformations is crucial, since after each vertical or horizontal transformation the pixels of the irregular image area are re-sorted and thereby one Correlation of the pixels in the local area can be lost.
  • Such a rearrangement can in particular be an alignment along a horizontal or a vertical axis (line).
  • the decision unit preferably determines the sequence of the transformations on the basis of special features or a special feature of the image area, its type of transmission or a feature characteristic of it.
  • One embodiment consists in that the image area is aligned along a horizontal line or that the alignment takes place along a vertical line. Pixels of the rows of the image area are aligned on the vertical line or pixels of the columns of the image area are aligned on the horizontal line. In particular, there is a corresponding alignment after each transformation (vertical or horizontal). By alignment, i.e. the shifting of rows or columns of the image area, a correlation in the local area may be lost (in the case of an irregular structure for the image area), since pixels that are next to one another will no longer necessarily be next to one another after alignment (e.g. correlation in
  • This information is used in particular to make the decision about the order of the transformations within the decision unit in such a way that the correlation of pixels lying next to one another in the local or time range is optimally used.
  • One embodiment also consists in the decision unit taking into account at least one of the following mechanisms for determining the sequence of vertical and horizontal transformation: a) With interlaced transmission, only every second line of an image is displayed (and transmitted). By alternating the other two lines, images are created with a time delay, which represent moving images, with the lines of two images that follow one another in time complementing one another to form a full image. In the decision unit, for example, the image header is used to determine whether there is such an interlaced transmission. If there is an interlace method, the horizontal and then the vertical transformation is carried out first. This takes advantage of the fact that in the interlaced method only every second line is transmitted and the correlation of pixels within a line is therefore higher than along a column.
  • an additional dimension is taken into account in the transformation, this additional dimension being examined with regard to the correlation of the pixels in the additional dimension.
  • the additional dimension is a time axis (3D transformation).
  • the decision unit generates side information in which the order of the transformations is contained.
  • the side information corresponds to a signal which is preferably transmitted to a receiver (decoder) and on the basis of which this receiver is able to extract the information about the sequence of the ⁇ transformations. This sequence must be taken into account accordingly in the inverse operation of the decoding.
  • the horizontal transformation results in the vertical transformation by performing a mirroring on a 45 ° axis before the transformation. Accordingly, a horizontal transformation emerges from the vertical transformation. Due to the mirroring, the transformation order is (virtually) exchanged.
  • the method is suitable for use in a coder for compressing image data, e.g. an MPEG picture encoder.
  • a corresponding decoder is preferably expanded to include an evaluation option for the side information signal in order to be able to carry out the correct sequence of vertical and horizontal transformation (or the inverse operation in each case) when decoding the image area.
  • Coders and decoders preferably operate according to an MPEG standard or an H.26x standard.
  • the transformation is a DCT transformation or an inverse IDCT transformation.
  • an arrangement for transforming an image area is specified with a decision unit by means of which a vertical transformation of the image area and then a horizontal transformation of the image area or vice versa, first the horizontal transformation and then the vertical transformation of the image area can be carried out.
  • Fig.l is a sketch showing steps of transforming an image area
  • FIG. 3 is a sketch illustrating a transmitter and receiver for image compression
  • 5 shows a possible form of the decision unit in the form of a processor unit.
  • Step 101 shows the irregular structure of the image area in an interlaced method, indicated by every other occupied line.
  • the image area is composed of lines 105, 106, 107 and 108.
  • step 102 the image that is actually shown in the interlace method is shown, which in turn has lines 105 to 108. The correlation of this
  • Image area with an irregular structure is particularly high along the lines. Accordingly, in the interlacing method, the lines are first transformed after they have previously been aligned along a vertical line 109. The alignment results in a column-related shift of adjacent pixels. The vertical transformation takes place in the Step 103. A horizontal alignment along a horizontal line 110 is carried out beforehand.
  • Step 101 are also interpreted as a representation of a plurality of lines 105 to 108 or a plurality of image areas 105 to 108 which are scanned along a time axis 111 at different times in each case.
  • the location information in the respective lines 105 to 108 or the respective image areas 105 to 108 is high, whereas the correlation between the individual lines 105 to 108 or image areas 105 to 108 is lower due to the scanning along the time axis 111 in the direction of the time dimension.
  • FIG. 2 represents a decision unit and the signals / values generated therefrom.
  • An input signal or a plurality of input signals 200 are used by the decision unit 201 to determine which of several transformations (horizontal, vertical, temporal) are to be carried out in which order in order to make the best possible use of the correlations in the local or time domain, ie to take high correlations into account in this way that an associated transformation is performed first.
  • the interlaced method discussed in FIG. 1 is used as an example, by means of which the decision unit 201 carries out the horizontal transformation before the vertical transformation.
  • the actual transformations are carried out in a unit 202, in which the image areas are also aligned.
  • the resulting coefficients 203 are the result of the transformation unit 202 (see also illustration in step 104). Furthermore, the decision unit 201 generates side information 203 which contains the sequence of the transformations to be carried out.
  • the arrangement shown in Figure 2 is in particular part of a transmitter (encoder) 301, as shown in Figure 3.
  • Image data 303 preferably in compressed form, is transmitted from the transmitter 301 to a receiver (decoder) 302.
  • the page information 203 described in FIG. 2 is also transmitted (here identified by a connection 304) from the transmitter 301 to the receiver 302.
  • the page information 304 is decoded there and the information about the order of the transformations is obtained therefrom.
  • Transformation emerges by mirroring the image area on a 45 ° axis (top left to bottom right). Due to the mirroring, the transformation order is (virtually) exchanged. Accordingly, the mirroring operation on the part of the receiver 302 must be taken into account.
  • FIG. 1 shows an image or with an associated image decoder in a higher degree of detail (block-based image coding method according to the H.263 standard).
  • a video data stream to be encoded with chronologically successive digitized images is fed to an image coding unit 201.
  • the digitized images are divided into macro blocks 202, each
  • Macroblock has 16x16 pixels.
  • the macro block 202 comprises 4 picture blocks 203, 204, 205 and 206, each picture block 8x8 Contains pixels to which luminance values (brightness values) are assigned.
  • each macroblock 202 comprises two chrominance blocks 207 and 208 with chrominance values (color information, color saturation) assigned to the pixels.
  • luminance value, first chrominance value and second chrominance value are referred to as color values.
  • the image blocks are fed to a transformation coding unit 209.
  • a transformation coding unit 209 In the case of differential image coding, values to be coded from image blocks of temporally preceding images are subtracted from the image blocks to be currently coded; only the difference formation information 210 is supplied to the transformation coding unit (Discrete Cosine Transformation, DCT) 209.
  • the current macroblock 202 is communicated to a motion estimation unit 229 via a connection 234.
  • Spectral coefficients 211 are formed in the transformation coding unit 209 for the picture blocks or difference picture blocks to be coded and fed to a quantization unit 212.
  • This quantization unit 212 corresponds to the quantization device according to the invention.
  • Quantized spectral coefficients 213 are supplied to both a scan unit 214 and an inverse quantization unit 215 in a reverse path.
  • a scanning method for example a "zigzag" scanning method
  • entropy coding is carried out on the scanned spectral coefficient 232 in an entropy coding unit 216 provided for this purpose.
  • the entropy-coded spectral coefficients are transmitted as coded image data 217 to a decoder via a channel, preferably a line or a radio link.
  • An inverse quantization of the quantized spectral coefficients 213 takes place in the inverse quantization unit 215.
  • Spectral coefficients 218 obtained in this way are fed to an inverse transformation coding unit 219 (inverse discrete cosine transformation, IDCT).
  • IDCT inverse discrete cosine transformation
  • Reconstructed coding values (also differential coding values) 220 are fed to an adder 221 in the differential image mode.
  • the adder 221 also receives coding values of an image block, which result from a temporally preceding image after motion compensation has already been carried out.
  • Reconstructed image blocks 222 are formed with the adder 221 and stored in an image memory 223.
  • Chrominance values 224 of the reconstructed image blocks 222 are fed from the image memory 223 to a motion compensation unit 225.
  • an interpolation takes place in an interpolation unit 227 provided for this purpose.
  • the number of brightness values contained in the respective image block is preferably doubled on the basis of the interpolation.
  • All brightness values 228 are supplied to both the motion compensation unit 225 and the motion estimation unit 229.
  • the motion estimation unit 229 also receives the image blocks of the macro block to be coded in each case (16 ⁇ 16 pixels) via the connection 234. In the motion estimation unit 229, the motion is estimated taking into account the interpolated brightness values (“motion estimation on a half-pixel basis”).
  • motion estimation on a half-pixel basis Preferably at
  • Motion estimation of absolute differences between the individual brightness values in the macro block 202 currently to be coded and the reconstructed macro block is determined from the previous image.
  • the result of the motion estimation is a motion vector 230 through which a local shift of the selected one Macroblocks from the temporally preceding picture to the macroblock 202 to be encoded is expressed.
  • Both brightness information and chrominance information relating to the macroblock determined by the motion estimation unit 229 are shifted by the motion vector 230 and subtracted from the coding values of the macroblock 202 (see data path 231).
  • FIG. 5 shows a processor unit PRZE which is suitable for carrying out transformation and / or
  • the processor unit PRZE comprises a processor CPU, a memory SPE and an input / output interface IOS, which is used in different ways via an interface IFC: an output is visible on a monitor MON and / or on a printer via a graphic interface PRT issued. • An entry is made via a mouse MAS or a keyboard TAST.
  • the processor unit PRZE also has a data bus BUS, which ensures the connection of a memory MEM, the processor CPU and the input / output interface IOS.
  • additional components can be connected to the data bus BUS, for example additional memory, data storage (hard disk) or scanner.

Landscapes

  • Engineering & Computer Science (AREA)
  • Multimedia (AREA)
  • Signal Processing (AREA)
  • Physics & Mathematics (AREA)
  • Discrete Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Compression Or Coding Systems Of Tv Signals (AREA)
  • Compression, Expansion, Code Conversion, And Decoders (AREA)

Abstract

L'invention concerne un procédé pour la transformation d'une zone d'image, selon lequel une unité de décision effectue tout d'abord une transformation verticale puis une transformation horizontale de la zone d'image, ou vice-versa.
EP00906176A 1999-02-01 2000-02-01 Procede et dispositif pour la transformation d'une zone d'image Withdrawn EP1157557A1 (fr)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
DE19903859 1999-02-01
DE19903859A DE19903859A1 (de) 1999-02-01 1999-02-01 Verfahren und Anordnung zur Transformation eines Bildbereichs
PCT/DE2000/000278 WO2000046998A1 (fr) 1999-02-01 2000-02-01 Procede et dispositif pour la transformation d'une zone d'image

Publications (1)

Publication Number Publication Date
EP1157557A1 true EP1157557A1 (fr) 2001-11-28

Family

ID=7895990

Family Applications (1)

Application Number Title Priority Date Filing Date
EP00906176A Withdrawn EP1157557A1 (fr) 1999-02-01 2000-02-01 Procede et dispositif pour la transformation d'une zone d'image

Country Status (6)

Country Link
EP (1) EP1157557A1 (fr)
JP (1) JP2002536926A (fr)
KR (1) KR20010101916A (fr)
CN (1) CN1339225A (fr)
DE (1) DE19903859A1 (fr)
WO (1) WO2000046998A1 (fr)

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE102013107719B4 (de) 2013-07-19 2015-08-13 Deutsche Telekom Ag Verfahren und Vorrichtung zur blockbasierten Dekorrelation von Bildsignalen
US10904563B2 (en) * 2019-01-02 2021-01-26 Tencent America LLC Method and apparatus for improved zero out transform

Family Cites Families (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5126962A (en) * 1990-07-11 1992-06-30 Massachusetts Institute Of Technology Discrete cosine transform processing system
DE4437827A1 (de) * 1994-10-14 1996-04-18 Hertz Inst Heinrich Schaltungsanordnung für ein Fernsehsystem, das transformationskodierte digitale Bilddaten verwendet

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
See references of WO0046998A1 *

Also Published As

Publication number Publication date
JP2002536926A (ja) 2002-10-29
DE19903859A1 (de) 2000-09-21
KR20010101916A (ko) 2001-11-15
WO2000046998A1 (fr) 2000-08-10
CN1339225A (zh) 2002-03-06

Similar Documents

Publication Publication Date Title
DE69735838T2 (de) Videokodierer mit Transformationskoeffizientenprädiktion
DE69535228T2 (de) Bildumsetzungsvorrichtung
DE69738494T2 (de) Videokodierungs- und Videodekodierungsvorrichtung
DE60027955T2 (de) Verfahren und Vorrichtung zur kontextbasierten Inter/Intra Kodierungsmodeauswahl
EP1025708B1 (fr) Procede et dispositif pour le traitement d'une image numerique
DE4442643B4 (de) Verfahren zum Abschätzen der Bewegung in einem Bewegtbild
EP1774790B1 (fr) Procede et dispositif de codage et de decodage
DE69915843T2 (de) Teilbandkodierung/-dekodierung
DE10196431B4 (de) Alternative Blockreihenfolgen zur besseren Vorhersage
DE19717608B4 (de) Wahrnehmungsfehlerbearbeitungsverfahren und Bildkodierungsvorrichtung, welche dieses Verfahren verwendet
EP0346637B1 (fr) Procédé pour le traitement et la transmission d'une séquence d'images
DE10022520A1 (de) Verfahren zur örtlichen skalierbaren Bewegtbildcodierung
EP1285537B1 (fr) Procede et agencement pour le codage et le decodage d'une suite d'images
EP1110407B1 (fr) Procede et dispositif pour le codage et le decodage d'une image numerisee faisant appel a un vecteur de deplacement total
WO2000008601A1 (fr) Procede et dispositif d'evaluation du mouvement dans une image numerisee possedant des pixels
DE69909880T2 (de) Dekodierung eines komprimierten digitalen Bildsignals
WO2000019373A1 (fr) Procede et systeme de traitement d'une image numerisee dotee de points d'images
EP0346636B1 (fr) Procédé pour le traitement et la transmission d'une séquence d'images
WO2000046998A1 (fr) Procede et dispositif pour la transformation d'une zone d'image
DE69923725T2 (de) Verfahren und Gerät für die Herausziehung von Farbkonturinformation aus Videohalbbildern
WO2001062009A1 (fr) Procede et dispositif de codage, ou de codage et decodage d'une suite de nombres
WO2001049038A1 (fr) Procede, dispositif et produit programme informatique servant a effectuer une prediction lors du codage d'une image divisee en blocs d'image
DE3726601A1 (de) Voraussehendes kodiersystem fuer fernsehsignale
DE10219640A1 (de) Verfahren zum Codieren und Decodieren von Videosequenzen und Computerprogrammprodukt
DE19944300C2 (de) Verfahren, Anordnung und Computerprogrammerzeugnis zur Bewegungsschätzung bei der Codierung von einem Bildobjekt in einem Bild

Legal Events

Date Code Title Description
PUAI Public reference made under article 153(3) epc to a published international application that has entered the european phase

Free format text: ORIGINAL CODE: 0009012

17P Request for examination filed

Effective date: 20010605

AK Designated contracting states

Kind code of ref document: A1

Designated state(s): AT BE CH CY DE DK ES FI FR GB GR IE IT LI LU MC NL PT SE

GRAH Despatch of communication of intention to grant a patent

Free format text: ORIGINAL CODE: EPIDOS IGRA

STAA Information on the status of an ep patent application or granted ep patent

Free format text: STATUS: THE APPLICATION IS DEEMED TO BE WITHDRAWN

18D Application deemed to be withdrawn

Effective date: 20020902