DE4308263B4 - Method for adaptive quantization in digital subband coding - Google Patents

Method for adaptive quantization in digital subband coding Download PDF

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DE4308263B4
DE4308263B4 DE4308263A DE4308263A DE4308263B4 DE 4308263 B4 DE4308263 B4 DE 4308263B4 DE 4308263 A DE4308263 A DE 4308263A DE 4308263 A DE4308263 A DE 4308263A DE 4308263 B4 DE4308263 B4 DE 4308263B4
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subband
activity
arrangement according
measured
activity measure
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Hamed Dr. Amor
Joachim Dr.-Ing. Dr. Wietzke
Bernd Schmale
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Robert Bosch GmbH
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    • 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
    • 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
    • H04N19/124—Quantisation
    • H04N19/126—Details of normalisation or weighting functions, e.g. normalisation matrices or variable uniform quantisers
    • 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
    • H04N19/169—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals using adaptive coding characterised by the coding unit, i.e. the structural portion or semantic portion of the video signal being the object or the subject of the adaptive coding
    • H04N19/17—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals using adaptive coding characterised by the coding unit, i.e. the structural portion or semantic portion of the video signal being the object or the subject of the adaptive coding the unit being an image region, e.g. an object
    • H04N19/176—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals using adaptive coding characterised by the coding unit, i.e. the structural portion or semantic portion of the video signal being the object or the subject of the adaptive coding the unit being an image region, e.g. an object the region being a block, e.g. a macroblock
    • 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
    • H04N19/60—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals using transform coding
    • H04N19/61—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals using transform coding in combination with predictive 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
    • H04N19/60—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals using transform coding
    • H04N19/63—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals using transform coding using sub-band based transform, e.g. wavelets
    • 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
    • H04N19/115—Selection of the code volume for a coding unit prior to 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
    • H04N19/134—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
    • H04N19/146—Data rate or code amount at the encoder output
    • 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
    • H04N19/146—Data rate or code amount at the encoder output
    • H04N19/149—Data rate or code amount at the encoder output by estimating the code amount by means of a model, e.g. mathematical model or statistical model
    • 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
    • H04N19/146—Data rate or code amount at the encoder output
    • H04N19/15—Data rate or code amount at the encoder output by monitoring actual compressed data size at the memory before deciding storage at the transmission buffer

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  • Multimedia (AREA)
  • Signal Processing (AREA)
  • Image Processing (AREA)
  • Compression Or Coding Systems Of Tv Signals (AREA)

Abstract

Verfahren zur adaptiven Quantisierung in der Teilbandcodierung, dadurch gekennzeichnet, daß zur Auswahl der Quantisierungskennlinie in einem Teilband ein Aktivitätsmaß des eigenen Teil bandes und ein Aktivitätsmaß des übergeordneten Bandes oder Teilbandes ausgewertet wird.method for adaptive quantization in subband coding, characterized in that for selection the quantization characteristic in a subband an activity measure of their own Part bandes and an activity measure of the parent Band or subband is evaluated.

Figure 00000001
Figure 00000001

Description

Für die Übertragung von digitalen Videosignalen werden Quellencodierverfahren eingesetzt, um die erforderliche Datenrate zu reduzieren. Ein dafür immer wichtiger werdendes Verfahren in der Video-Quellencodierung ist die Teilband-Codierung [1]. Hier wird das digitale Eingangsvideosignal durch Filterbänke in zwei oder mehr Kanäle zerlegt, die dann die verschiedenen Frequenzbereiche des Signals beschreiben. Die Teilbandcodierung hat u.a. den Vorzug, daß die verschiedenen Teilbänder in unterschiedlicher Weise codiert werden können, entsprechend den charakteristischen Pixel-Statistiken des jeweiligen Bandes. Es gibt verschiedene übliche Strukturen zur Teilbandzerlegungen, einige sind in den Bildern 1a-c gezeigt.For the transmission of digital video signals, source coding methods are used, to reduce the required data rate. One for it always more important method in the video source coding is the subband coding [1]. Here is the digital input video signal through filter banks in two or more channels decomposed, which then describe the different frequency ranges of the signal. The subband coding has i.a. the advantage that the various subbands in different ways, according to the characteristic Pixel statistics of the respective band. There are several common structures for subband decompositions, some are shown in pictures 1a-c.

In der Codierung der Teilbänder finden sich zumeist Quantisierungs-Einheiten, in denen die dargestellten Daten abhängig von einem Aktivitätsmaß vergröbert werden, um damit das Datenaufkommen zu verringern. Die Quantisierungseinheiten sind im Bild 1c durch die Blöcke Q1, Q2, ... dargestellt. Daran schließen sich normalerweise Funktionsblöcke zur Lauflängenbestimmung (RLC) und zur Codierung mit variabler Länge (VLC) an.In the coding of the subbands are mostly quantization units, in which the illustrated Data dependent be coarsened by an activity measure, in order to reduce the data traffic. The quantization units are in the picture 1c through the blocks Q1, Q2, ... shown. This is normally followed by functional blocks for determining the run length (RLC) and for variable length coding (VLC).

Das sogenannte Aktivitätmaß wird bestimmt, indem in einem Datenblock z.B. die Summe der absoluten Differenzen zwischen benachbarten Pixelwerten von einer Recheneinheit (Funktionsblock AK in Bild 1c) gemessen und berechnet wird. Es gibt damit ein Maß für die Struktur und den Kontrast in einem Bildbereich an. Eine andere Meßmethode zur Bestimmung der Aktivität ist die Summation der quadrierten Differenzen zwischen benachbarten Pixelwerten. Diese Aktivität entspricht dann dem statistischen Maß der Varianz.The so-called activity measure is determined by in a data block e.g. the sum of the absolute differences between adjacent pixel values from a computing unit (function block AK in Figure 1c) is measured and calculated. It gives a measure of the structure and the contrast in an image area. Another method of measurement to determine the activity is the summation of the squared differences between adjacent ones Pixel values. This activity then corresponds to the statistical measure of variance.

Eine dritte Meßmethode zur Bestimmung der Aktivität ist die Summation der absoluten Pixelbeträge. Diese Methode eignet sich vor allem für, in einer oder mehrere Richtungen, hochpaßgefilterte Teilbänder, da hier die Differenzbildung zwischen benachbarten Pixeln bereits implizit in der Hochpaßfilterung steckt.A third method of measurement to determine the activity is the summation of the absolute pixel amounts. This method is suitable especially for, in one or more directions, high pass filtered subbands, since here the difference between adjacent pixels already implicit in high-pass filtering.

In der Quantisierungs-Einheit wird üblicherweise in Abhängigkeit des gemessenen Aktivitätswertes in einem Band eine Quantisierungskennlinie für den entsprechenden Datenblock ausgewählt. Damit kann auf die Besonderheiten der visuellen Wahrnehmung eingegangen werden, die in kontrastreichen Bildbereichen hoher Aktivität eine gröbere Quantisierung der Daten ohne wahrnehmbare Qualitätseinbußen zuläßt.In the quantization unit becomes common dependent on the measured activity value in a band a quantization characteristic for the corresponding data block selected. With this, we can discuss the peculiarities of visual perception in high-contrast image areas of high activity a coarser quantization the data allows without perceptible loss of quality.

Problematisch sind allerdings Bildvorlagen mit feinen Strukturen, in denen in den niederfrequenten Bändern nur wenig Kontraste zu finden sind, in denen aber zugleich aufgrund der feinen Strukturen in den höheren Bändern hohe Aktivitäten gemessen werden.Problematic are, however, picture templates with fine structures in which the low frequency bands only a few contrasts can be found, but at the same time due to the fine structures in the higher ones bands high activities be measured.

Erfindungsgemäß wird nun deshalb nicht nur die gemessene Aktivität innerhalb des Bandes zur Adaption der Quantisierung herangezogen, sondern auch die Aktivität des in der Hierarchie der Teilbandzerlegungen darüberliegenden Bandes. Dies ist in Bild 2 beispielhaft für eine Struktur dargestellt. Mit derartigen Anordnungen lassen sich die Maskierungseffekte der visuellen Wahrnehmung besser ausnutzen, wodurch ein zusätzlicher Codiergewinn erreicht werden kann.According to the invention will now therefore not only the measured activity within the band for adaptation the quantization, but also the activity of the the hierarchy of subband decompositions overlying band. This is in picture 2 exemplarily for a structure is shown. With such arrangements can be make better use of the masking effects of visual perception, whereby an additional Coding profit can be achieved.

Ein etwas geringerer Codiergewinn kann erzielt werden, indem statt der Aktivität des darüberliegenden Bandes das niederfrequente Band der gleichen Hierarchieebene mit ausgewertet wird. Eine solche Anordnung, die im Bild 3 beispielhaft dargestellt ist, kann gegebenenfalls mit geringerem Aufwand realisierbar sein.One a slightly lower coding gain can be achieved by replacing the activity of the overlying Bandes the low-frequency band of the same hierarchical level with is evaluated. Such an arrangement, the example in Figure 3 can be realized, if necessary, with less effort feasible be.

Literaturliterature

  • [1] Digital Image Compression Techniques; Rabbani, Majid; Jones, Paul W; SPIE Optical Engineering Press, Washington 1991, ISBN 0-8194-0648-1[1] Digital Image Compression Techniques; Rabbani, Majid; Jones, Paul W; SPIE Optical Engineering Press, Washington 1991, ISBN 0-8194-0648-1

Claims (5)

Verfahren zur adaptiven Quantisierung in der Teilbandcodierung, dadurch gekennzeichnet, daß zur Auswahl der Quantisierungskennlinie in einem Teilband ein Aktivitätsmaß des eigenen Teil bandes und ein Aktivitätsmaß des übergeordneten Bandes oder Teilbandes ausgewertet wird.Method for adaptive quantization in the subband coding, characterized in that for the selection of the quantization characteristic in a subband an activity measure of the own subband and an activity measure of the superordinate band or subband is evaluated. Anordnung nach Anspruch 1, dadurch gekennzeichnet, daß zur Schaltungsvereinfachung statt des Aktivitätsmaßes des übergeordneten Bandes oder Teilbandes das Aktivitätsmaß des niederfrequenten Teilbandes der gleichen Aufspaltungsebene ausgewertet wird.Arrangement according to claim 1, characterized that to Circuit simplification instead of the activity measure of the higher band or subband the activity measure of the low-frequency subband evaluated at the same level of division. Anordnung nach Anspruch 1 und/oder 2, dadurch gekennzeichnet, daß zur Bestimmung der Aktivität in einem Datenblock die Summe der absoluten Differenzen zwischen benachbarten Pixelwerten gemessen und berechnet wird.Arrangement according to claim 1 and / or 2, characterized that to Determination of activity in a data block the sum of the absolute differences between adjacent pixel values are measured and calculated. Anordnung nach Anspruch 1 und/oder 2, dadurch gekennzeichnet, daß zur Bestimmung der Aktivität in einem Datenblock die Summe der quadrierten Differenzen zwischen benachbarten Pixelwerten gemessen und berechnet wird.Arrangement according to claim 1 and / or 2, characterized in that for determining the Ak In a data block, the sum of the squared differences between adjacent pixel values is measured and calculated. Anordnung nach Anspruch 1 und/oder 2, dadurch gekennzeichnet, daß zur Bestimmung der Aktivität in einem Datenblock die Summe der absoluten Pixelwerte gemessen und berechnet wird.Arrangement according to claim 1 and / or 2, characterized that to Determination of activity measured in a data block, the sum of the absolute pixel values and is calculated.
DE4308263A 1993-03-16 1993-03-16 Method for adaptive quantization in digital subband coding Expired - Fee Related DE4308263B4 (en)

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US5870434A (en) * 1994-12-29 1999-02-09 Sony Corporation Apparatus and method for quantizing a digital signal based on quantizing steps including odd-numbered steps
GB2351407B (en) * 1999-06-21 2003-06-11 Sony Uk Ltd Video data compression

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RABBANI, Majid; JONES, Paul W.: Digital Image Compression Techniques, SPIE Optical Engineering Press, Washington 1991, S. 180 *

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