WO1998043434A1 - Procede et ensemble pour l'evaluation assistee par ordinateur du mouvement d'un element d'une image a coder - Google Patents

Procede et ensemble pour l'evaluation assistee par ordinateur du mouvement d'un element d'une image a coder Download PDF

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Publication number
WO1998043434A1
WO1998043434A1 PCT/DE1998/000779 DE9800779W WO9843434A1 WO 1998043434 A1 WO1998043434 A1 WO 1998043434A1 DE 9800779 W DE9800779 W DE 9800779W WO 9843434 A1 WO9843434 A1 WO 9843434A1
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WO
WIPO (PCT)
Prior art keywords
image
rbe
reference picture
error measure
obe
Prior art date
Application number
PCT/DE1998/000779
Other languages
German (de)
English (en)
Inventor
Jürgen PANDEL
Albert Salai
Original Assignee
Siemens Aktiengesellschaft
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 Aktiengesellschaft filed Critical Siemens Aktiengesellschaft
Priority to JP54467598A priority Critical patent/JP2002501697A/ja
Priority to EP98925399A priority patent/EP0970586A1/fr
Publication of WO1998043434A1 publication Critical patent/WO1998043434A1/fr

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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
    • H04N19/50—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals using predictive coding
    • H04N19/503—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals using predictive coding involving temporal prediction
    • H04N19/51—Motion estimation or motion compensation
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N5/00—Details of television systems
    • H04N5/14—Picture signal circuitry for video frequency region
    • H04N5/144—Movement detection
    • H04N5/145—Movement estimation

Definitions

  • the invention relates to the computer-based motion estimation of an element of an image to be encoded.
  • a method for image coding is known from [5], in which motion vectors are determined for an image and from the motion vectors an optimal motion vector is selected from the motion vectors with regard to the actual motion of an image block.
  • a further block-based image coding method is known from [6], in which a statistical distribution of the differential image signal is determined. Depending on the statistical distribution, a decision is made as to whether an image block to be encoded is encoded or not.
  • a motion estimation is carried out in both the block-based and the object-based image coding using conventional methods.
  • an element of an image to be coded is attempted to determine whether a before encoded image contains an area that matches the area to be encoded so well that it is sufficient with sufficient picture quality to encode only a reference to the already encoded area instead of encoding the entire element to be encoded. Since the respective element is usually shifted between successive images, the reference is made in the form of a so-called motion vector, which describes the shift of the area from the previous image to the element m of the image to be coded.
  • block matching method is usually used for block-based image compression methods. It is based on the fact that the picture block to be coded is compared with blocks of the same size of a previous picture.
  • the previous image is referred to below as the reference image.
  • One of the reference picture blocks is in the same position as the picture block to be coded, the other reference blocks are shifted in relation to this.
  • fill search a full search
  • matchmgs a corresponding number of block comparisons
  • coding information is understood to mean, for example, luminance information or chrominance information associated with the respective pixel.
  • the so-called spiral search method is also known as a search strategy.
  • all search positions are again processed, but in a spiral, ie starting from the so-called zero shift, ie from the same position as the block to be coded.
  • the search positions are selected on a spiral curve around the zero shift, the search positions being always further away from the zero shift.
  • the motion vector is assigned to that search position in which the sum of the absolute differences in the coding information of the image block to be coded and the corresponding image block m is minimal in the reference image.
  • the invention is based on the problem of specifying a method for motion estimation with which the motion characteristics of elements of digitized images in a moving image sequence are better taken into account in the context of image coding than is possible with known methods.
  • the method uses components of motion vectors or motion vectors of previously processed image elements, i.e. a frequency distribution was determined for picture elements for which a motion estimation had already been carried out.
  • a frequency distribution was determined for picture elements for which a motion estimation had already been carried out.
  • at least one search position is determined.
  • a reference picture element is determined at the search position.
  • An error measure is determined for the original picture element, the error measure being used to describe the similarity between the original picture element and the reference picture element.
  • the location of the reference picture element determines the search position.
  • an image block BB as an image element which has, for example, 8x8 pixels.
  • macro blocks which usually consist of 4 or 6 image blocks.
  • a picture element is to be understood as an elementary unit of any shape and size, in which the picture B is divided and for which the respective coding method takes place.
  • a search strategy for a new motion vector is proposed for the first time, which is adapted to the vector statistics of motion vectors already found or components of motion vectors in the same image or to the vector statistics of the images in the past.
  • the picture coding is thus better adapted to the movement characteristics of the moving picture sequence, which reduces the computation effort required for the movement estimation.
  • an image memory for storing the digitized images and a processor unit are provided with which the individual method steps of the method are carried out.
  • the arrangement also has the above-mentioned advantages of the method compared to the known method for motion estimation.
  • the error measure which can be formed by a sequence of accumulations of difference values, which Abort determination of the error measure with respect to a reference picture element if the value of the error measure with respect to the respectively examined reference picture element is greater than a predeterminable threshold value.
  • This procedure avoids unnecessary additional computing operations, which leads to a saving in the computing power required for the arrangement when carrying out the method.
  • the threshold value is of variable design and the threshold value is assigned the value of the error measure of the image element considered to be optimal in the previous method. In this way, a further reduction in required arithmetic operations is achieved.
  • the frequency distribution of the motion vectors or the components of motion vectors is taken into account very advantageously, since in the event that frequently occurring motion vectors are used to determine search positions in which the reference picture elements are preferably at an early stage Phase of the method are compared, a very good error measure and thus a very small threshold value is determined statistically very early, which, when the error measure is further determined with respect to further reference picture elements in the context of motion estimation, leads to the accumulations of the differences in the coding information in the further procedures can be terminated early. This saves a considerable amount of computing time compared to known methods for estimating movement.
  • FIG. 1 shows a computer arrangement with two computers, one
  • Camera and a transmission medium shows a sequence of digitized images which are stored in a memory of a computer
  • the camera K can be, for example, any analog camera K that records images of a scene and either digitizes these images in the camera K or also transmits them analogously to a computer R1, which then either processes the digitized images or digitizes the analog images Images are converted and the digitized images are processed.
  • the computer R1 has a processor unit P, with which the method step of motion estimation or motion compensation described in the following and possibly further method steps, for example for image coding, are carried out.
  • the processor unit P is coupled, for example, via a bus BU to a memory SP, in which the image data are stored.
  • the computer R1 will perform the image coding and, after the compressed image data has been transmitted via a transmission medium UM to another computer R2, the other computer R2 will perform the image decoding.
  • the further computer R2 has, for example, the same structure as the first computer R1, that is to say the memory SP, which is coupled to the processor unit P via the bus BU.
  • the digitized images or the reconstructed images can either be displayed on a first screen BS1, which is coupled to the first computer R1, or on a second screen BS2, which is coupled to the second computer R2.
  • the method for motion estimation can be used both in the context of so-called block-based image coding methods and in the context of object-based image coding methods.
  • a sequence of digitized images ZVB, EVB, OB is shown symbolically in FIG. 2 and is stored in the memory SP.
  • This representation is merely a symbolic representation, since in most image coding methods it is not the case that several successive images are completely stored in the memory SP. This representation therefore only serves to illustrate the method.
  • the aim of the motion estimation is to carry out an image coding for an original image OB of the image sequence.
  • the processed picture element BBE is already coded and thus already transmitted.
  • sufficiently similar means that it is sufficient with only a slight reduction in the image quality is to insert the processed picture element BBE with a possible shift, which takes place between the processed picture element BBE m the first preceding picture EVB and the element OBE of the original picture OB, in the picture decoding m the picture to be decoded, with which a complex coding of the element OBE des Origmalsentes OB no longer required
  • the displacement of the processed picture element BBE between the first preceding picture EVB and the respective element OBE of the original picture OB is referred to as the motion vector BV.
  • a motion vector BV is determined for each image block of an image or even just a so-called macro block, which has, for example, 4 or 6 image blocks, and is assigned to the image block or macro block.
  • FIG. 2 shows processed image elements BBE, each of which has been assigned a motion vector BV.
  • a frequency distribution of motion vectors BV of image elements BBE that have already been processed is determined. Any number of picture elements BBE that have already been processed can be within the original picture OB or within a Any number of previous pictures, for example the first previous picture EVB or also a second previous picture ZVB or further previous pictures are taken into account in the picture sequence.
  • the motion vector BV usually has a first component BV X and a second component BVy in the 2-dimensional space. Both components together form the motion vector BV.
  • a frequency distribution F of the motion vectors BV is shown as an example in FIG. 3c. It is the number for each component of the motion vector BV that occurs
  • ABV xy is shown, with which the frequency of the occurrence of the respective motion vector BV is described. This results in a 2-dimensional area F in a 3-dimensional space, which is spanned by the first component BV X , the second component BV y and the number ABV X y.
  • Fig. 3c it is shown as an example that the motion vector (2,1) occurred 6 times in the processed image elements BBE considered, which were used to determine the frequency distribution.
  • the motion vector (6,6) has occurred 5 times in this example.
  • a search position for the element OBE in the original image OB with respect to at least one reference image element RBE in the first preceding image EVB is determined depending on the frequency distribution F.
  • an error measure is also determined for the original picture element OBE. This is done, for example, by comparing the coding information in the first preceding picture EVB at the search position with the reference picture element RBE which contains the search position. mation, which contains the reference picture element RBE or the element OBE of the original picture OB, respectively.
  • the error measure takes place, for example, by forming the difference between the coding information of the individual pixels of the element OBE and the reference pixel RBE.
  • the sum of the quadratic differences is used.
  • search positions can be determined and thus also several difference picture elements RBE, each of which contains at least one search position.
  • the formation of the error measure is carried out in each case for a reference picture element RBE and the element OB of the original picture OB. That reference picture element RBE is selected and used in the context of the motion estimation as the reference picture element RBE most similar to the element OBE, which of the reference picture elements RBE taken into account, the element OB of the original picture OB has the greatest correspondence with the element OB of the original picture OB with regard to the error measure.
  • the order in which the individual reference picture elements RBE are examined depends on the frequency distribution of the motion vectors BV.
  • a predeterminable threshold value is also taken into account as part of this method.
  • the error measure is determined as long, i.e. the individual differences in the coding information are added up until the value of the error measure exceeds the threshold value.
  • Fig. 4 the method is shown summarized its individual method steps in a flow chart.
  • a frequency distribution of motion vectors BV and / or components of motion vectors BV X , BVy of processed image elements BBE of previous images EVB, ZVB, ... is determined.
  • At least one search position in a reference image EVB is determined as a function of the frequency distribution.
  • an error measure of the coding information of the element OBE of the original picture OB with respect to a reference picture element RBE at the search position is determined (403) as part of the motion estimation, the error measure being used to determine the similarity between the element OBE and the reference picture element RBE is described.
  • the camera K can, for example, also be a digital camera K, with which directly digitized images B are recorded and fed to the computer R1 for further processing.
  • the computer R1 can also be designed as an independent arrangement that carries out the method steps described, for example as an independent computer card that is installed in a computer.
  • the method can, however, also be used without any problems for object-based image coding methods.
  • object-based image coding methods it is only necessary that image objects of approximately the same shape and size are compared with one another as part of the motion estimation, since otherwise the result of the motion estimation could possibly be incorrect.
  • FIG. 3a shows that the first component BV X with a value 4 occurred 8 times in the processed picture elements BBE taken into account.
  • the first component BV X with a value of 1 has occurred twice, for example.
  • Such a frequency distribution for the second components BVy is shown in FIG. 3b.
  • the order in which the individual reference picture elements RBE are examined is selected in this case depending on the frequency distribution of the components BV X and BVy of the motion vectors BV.
  • the error measure can also be determined, for example, by summing the absolute difference between the pixels of the element OBE and the reference picture element RBE. Further options for forming the error measure are sufficiently ongoing and can be used without limitation within the scope of this procedure.
  • the threshold value i.e. in each case to set the threshold value to a new value if the error measure has been taken into account after taking into account all pixels in the respective elements OBE, RBE and the error measure is less than the previous threshold value.
  • the value of the error measure is assigned to the value of the threshold value.
  • the threshold value is carried out to the “optimal” value of the error measure when the method is carried out iteratively for a plurality of reference picture elements RBE.

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  • Engineering & Computer Science (AREA)
  • Multimedia (AREA)
  • Signal Processing (AREA)
  • Compression Or Coding Systems Of Tv Signals (AREA)

Abstract

Une première phase (401) de l'évaluation d'un mouvement consiste à calculer une distribution de fréquences de vecteurs de mouvements et/ou de composantes de vecteurs de mouvements d'une image. En fonction de la distribution de fréquences, au moins une position de recherche est déterminée (402) dans une image de référence. A la position de recherche considérée, un élément est déterminé pour un élément d'une image à coder puis une mesure d'erreurs est déterminée (403) pour l'élément ainsi déterminé. La mesure d'erreurs permet de décrire la similitude entre l'élément de l'image à coder et l'élément de l'image de référence.
PCT/DE1998/000779 1997-03-26 1998-03-16 Procede et ensemble pour l'evaluation assistee par ordinateur du mouvement d'un element d'une image a coder WO1998043434A1 (fr)

Priority Applications (2)

Application Number Priority Date Filing Date Title
JP54467598A JP2002501697A (ja) 1997-03-26 1998-03-16 符号化しようとする画像の画像要素のコンピュータ支援動き予測方法および装置
EP98925399A EP0970586A1 (fr) 1997-03-26 1998-03-16 Procede et ensemble pour l'evaluation assistee par ordinateur du mouvement d'un element d'une image a coder

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE19712785A DE19712785C1 (de) 1997-03-26 1997-03-26 Verfahren und Anordnung zur rechnergestützten Bewegungsschätzung eines Elements eines zu codierenden Bildes
DE19712785.1 1997-03-26

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WO1998043434A1 true WO1998043434A1 (fr) 1998-10-01

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EP (1) EP0970586A1 (fr)
JP (1) JP2002501697A (fr)
CN (1) CN1244992A (fr)
DE (1) DE19712785C1 (fr)
WO (1) WO1998043434A1 (fr)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2000070879A1 (fr) * 1999-05-13 2000-11-23 Stmicroelectronics Asia Pacific Pte Ltd. Estimateur de mouvement adaptatif

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP1110407B1 (fr) 1998-08-18 2002-05-08 Siemens Aktiengesellschaft Procede et dispositif pour le codage et le decodage d'une image numerisee faisant appel a un vecteur de deplacement total
EP1361541B1 (fr) * 2002-04-09 2011-06-22 STMicroelectronics Srl Procédé et processus d'éstimation de mouvement globale dans une série d'images, par exemple pour souris optiques

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EP0414113A2 (fr) * 1989-08-24 1991-02-27 Deutsche Thomson-Brandt Gmbh Procédé pour la compensation de mouvement dans un codeur ou un décodeur des images mouvantes
EP0557007A2 (fr) * 1992-02-15 1993-08-25 Sony Corporation Dispositif de traitement d'image
WO1995030310A1 (fr) * 1994-04-29 1995-11-09 Motorola, Inc. Procede permettant d'estimer le mouvement dans une sequence video
JPH08307880A (ja) * 1995-03-03 1996-11-22 Kokusai Denshin Denwa Co Ltd <Kdd> 動画像符号化装置

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US5028996A (en) * 1989-06-26 1991-07-02 Matsushita Electric Industrial Co., Ltd. Picture coding method
US5565921A (en) * 1993-03-16 1996-10-15 Olympus Optical Co., Ltd. Motion-adaptive image signal processing system

Patent Citations (4)

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Publication number Priority date Publication date Assignee Title
EP0414113A2 (fr) * 1989-08-24 1991-02-27 Deutsche Thomson-Brandt Gmbh Procédé pour la compensation de mouvement dans un codeur ou un décodeur des images mouvantes
EP0557007A2 (fr) * 1992-02-15 1993-08-25 Sony Corporation Dispositif de traitement d'image
WO1995030310A1 (fr) * 1994-04-29 1995-11-09 Motorola, Inc. Procede permettant d'estimer le mouvement dans une sequence video
JPH08307880A (ja) * 1995-03-03 1996-11-22 Kokusai Denshin Denwa Co Ltd <Kdd> 動画像符号化装置

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
PATENT ABSTRACTS OF JAPAN vol. 097, no. 003 31 March 1997 (1997-03-31) *

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2000070879A1 (fr) * 1999-05-13 2000-11-23 Stmicroelectronics Asia Pacific Pte Ltd. Estimateur de mouvement adaptatif
US7551673B1 (en) 1999-05-13 2009-06-23 Stmicroelectronics Asia Pacific Pte Ltd. Adaptive motion estimator

Also Published As

Publication number Publication date
DE19712785C1 (de) 1998-07-16
CN1244992A (zh) 2000-02-16
EP0970586A1 (fr) 2000-01-12
JP2002501697A (ja) 2002-01-15

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