*EP B1* EP B1 (19) (11) EP B1 (12) EUROPEAN PATENT SPECIFICATION

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Note: Within nine months from the publication of the mention of the grant of the European patent, any person may give notice to the European Patent Office of opposition to the European patent granted. Notice of opposition shall be filed in

European Patent Office Office européen des brevets

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0 961 991

B1

*EP000961991B1*

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EP 0 961 991 B1

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EUROPEAN PATENT SPECIFICATION

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Date of publication and mention of the grant of the patent: 16.06.2004 Bulletin 2004/25

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Application number: 98955858.0

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Date of filing: 07.12.1998

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Int Cl.7:

G06T 5/50, H04N 5/14,

H04N 7/26

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International application number: PCT/IB1998/001966

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International publication number:

WO 1999/033024 (01.07.1999 Gazette 1999/26)

(54) METHOD AND ARRANGEMENT FOR CREATING A HIGH-RESOLUTION STILL PICTURE

VERFAHREN UND ANORDNUNG ZUR ERZEUGUNG EINES STANDBILDES MIT HOHER

AUFLÖSUNG

PROCEDE ET SYSTEME PERMETTANT DE CREER UNE IMAGE FIXE DE HAUTE RESOLUTION

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Designated Contracting States:

DE FR GB

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Priority: 22.12.1997 EP 97204055

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Date of publication of application:

08.12.1999 Bulletin 1999/49

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Proprietor: Koninklijke Philips Electronics N.V. 5621 BA Eindhoven (NL)

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Inventor: KLEIHORST, Richard, P. NL-5656 AA Eindhoven (NL)

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Representative:

Groenendaal, Antonius Wilhelmus Maria et al Philips

Intellectual Property & Standards P.O. Box 220

5600 AE Eindhoven (NL)

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References cited:

JP-A- 7 015 654 US-A- 5 341 174 US-A- 5 657 402 US-A- 5 696 848

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5 10 15 20 25 30 35 40 45 50 55 Description

FIELD OF THE INVENTION

[0001] The invention relates to a method of creating a high-resolution still picture, comprising the steps of: receiving a sequence of lower-resolution pictures; esti-mating motion in said sequence of lower-resolution pic-tures with sub-pixel accuracy; and creating the high-res-olution still picture from said sequence of lower-resolu-tion pictures and said estimated molower-resolu-tion. The invenlower-resolu-tion also relates to an arrangement for creating a high-res-olution still picture, for example, an electronic still-pic-ture camera.

BACKGROUND OF THE INVENTION

[0002] A prior-art method of creating a high-resolution still picture as defined in the opening paragraph is dis-closed in European Patent Application EP-A-0 731 600. In this prior-art method, one of the lower resolution pic-tures is selected as a reference picture, and the relative motion between the pixels of the reference picture and each one of the other pictures is estimated with sub-pixel accuracy. Using the motion thus estimated, the lower resolution pictures are scaled to the high-resolu-tion domain and combined to form the high-resoluhigh-resolu-tion picture. The relative motion is represented in the form of a mapping transform.

OBJECT AND SUMMARY OF THE INVENTION [0003] It is an object of the invention to provide a method of creating still pictures with advantageous ef-fects in terms of performance and practical implemen-tations.

[0004] To this end, the method in accordance with the invention comprises the steps of subjecting the se-quence of pictures to motion-compensated predictive encoding, thereby generating motion vectors represent-ing motion between successive pictures of said se-quence; decoding said encoded pictures; and creating the high-resolution picture from said decoded pictures and the motion vectors generated in said encoding step. [0005] The creation of a high-resolution picture from a sequence of lower-resolution pictures relies on the availability of sub-pixel motion information. Employing motion-compensated predictive encoding based on mo-tion between successive pictures (instead of momo-tion be-tween each picture and a fixed reference picture) in-creases the probability that motion vectors with sub-pix-el accuracy will be obtained. The performance of the method is thus considerably improved. The invention al-so has the advantage that the sequence of motion-com-pensated predictively encoded lower-resolution pic-tures is a compressed representation of the high-reso-lution still picture. Accordingly, the still picture can effi-ciently be stored and/or transmitted. Because the

mo-tion vectors are part of the stored data, the high-resolu-tion still picture can then be obtained without necessi-tating another motion estimator. A further advantage is that, upon reproduction, the user may select creation of the high-resolution still picture or playback of the original lower-resolution video sequence.

[0006] Preferably, the step of encoding the sequence of pictures comprises the use of an MPEG encoder which is arranged to produce an IPPP.. sequence of en-coded pictures. Cost-effective MPEG encoders with high compression ratios are readily available.

[0007] In an embodiment of the invention, the high-resolution still picture is created by recursively adding a current decoded picture to a previously created picture, said previously created picture being subjected to mo-tion-compensation in accordance with the motion vector which is associated with the current decoded picture. It is thereby achieved that the still picture is gradually built-up in a single picture memory.

[0008] The invention can also be used to create a high-resolution still picture from an already available (re-ceived or recorded) sequence of motion-compensated predictively encoded lower-resolution pictures, for ex-ample, an MPEG bitstream.

BRIEF DESCRIPTION OF THE DRAWINGS [0009]

Fig. 1 shows various pictures to illustrate the prior art method of creating a high-resolution picture. Fig.2 shows a block diagram of a system carrying out the method of creating a high-resolution picture in accordance with the invention.

Figs. 3 and 4 show various pictures to illustrate the operation of the system which is shown in Fig.2. DESCRIPTION OF EMBODIMENTS

[0010] Fig. 1 shows various pictures to illustrate the prior art method of creating a high-resolution picture. In this Figure, the pictures A1, A2and A3show three suc-cessive phases of a moving object. The pictures B1, B2

and B3denote the corresponding pixel values on a

low-resolution grid as generated by a low-low-resolution image sensor. Throughout this description, pixels will have a value in the range 0-100, the value 0 not being shown in the various picture diagrams.

[0011] In the prior art, amounts of motion are calcu-lated between the pixels of a fixed reference picture and each one of the subsequent pictures. In the example shown in Fig.1, picture B1is the reference picture. To simplify the example, it is assumed that all pixels of the object have the same amount of motion, so that a single motion vector is obtained for each subsequent picture. Accordingly, motion vector m12represents the amount

of motion between pictures B1and B2. The vector is

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by 1 pixel to the right andυ pixel upwards. Similarly, the motion vector m13indicates the amount of motion be-tween pictures B1and B3. This vector is assumed to

have the value m13=(1υ, υ).

[0012] The pictures C1, C2and C3are the respective versions of pictures B1, B2and B3on the high-resolution

grid. They are obtained by up-sampling. In this example, in which the motion estimation is carried out at half-pixel accuracy, the high resolution is twice the low resolution in both the horizontal and the vertical direction. The up-sampling is carried out by repeating each pixel four times.

[0013] The pictures D1, D2and D3are the pictures

ob-tained by moving back the pictures C1, C2 and C3

through a distance corresponding to their motion vec-tors. The respective motion vectors m'12and m'13in the

high-resolution domain are obtained by multiplying the original motion vectors m12and m13in the low-resolu-tion domain by the resolulow-resolu-tion enhancement factor -2. Thus, picture C2is shifted 2 pixels to the left and 1 pixel

downwards, and picture C3is shifted 3 pixels to the left and 1 pixel downwards.

[0014] Finally, picture E is the result of adding togeth-er the pictures D1, D2and D3, and dividing the sum by

3 (the number of pictures). As can be seen, picture E starts to reveal high-resolution details of the original ob-ject. The more further pictures are processed in this manner, the better the resemblance.

[0015] Fig.2 shows a block diagram of a system car-rying out the method in accordance with the invention. The system comprises an image sensor 1, a motion-compensated prediction encoder 2, a storage medium (or transmission channel) 3, a motion-compensated prediction decoder 4 and a processing circuit 5 for cating the high-resolution picture. The image sensor re-ceives images Aicorresponding to the pictures A1, A2

and A3shown in Fig. 1, and generates digitized

low-res-olution pictures Bicorresponding to the pictures B1, B2 and B3 shown in Fig.1.

[0016] The motion-compensated prediction encoder 2 (preferably a standard MPEG encoder such as the Philips integrated circuit SAA7650) encodes and com-presses the pictures in accordance with the MPEG2 coding standard. The encoder comprises a subtracter 21, an adder 22, a frame memory 23, a motion estimator 24 and a motion compensator 25. Elements which are not essential for understanding the invention, such as a discrete cosine transformer, a quantizer and a variable-length encoder have been omitted. The operation of the encoder will briefly be explained with reference to Fig. 3. In this Figure, the input images A1, A2and A3and their digital counterparts B1, B2and B3are the same as in Fig.1.

[0017] The first picture B1of the sequence is autono-mously encoded. In MPEG coding, such a picture is usu-ally referred to as an I-picture. In Fig.3, picture D1shows

the pixel values of the autonomously encoded picture. The picture is applied to the encoder's output and also

stored in the frame memory 23.

[0018] The further pictures B2and B3are predictively encoded. In MPEG coding, they are usually referred to as P-pictures. To encode these pictures, the motion es-timator 24 calculates the amount of motion between the current picture Biand the stored previously encoded

pic-ture Bi-1. Usually, said motion estimation is carried out

on the basis of blocks of 16*16 pixels. Using the calcu-lated motion vector, the motion compensator 25 gener-ates a prediction picture Ciwhich is subtracted from the

picture Bito be encoded so as to form a difference output picture Di. The prediction image Ciand the encoded dif-ference Di are added by adder 22 and stored in the

frame memory 23.

[0019] Picture C2in Fig.3 is the motion-compensated prediction picture for encoding the picture B2. As in the

prior art, the relevant motion vector m12is assumed to

have the value (1,υ). Picture B2is thus encoded in the

form of a difference picture which is shown as D2in Fig. 3.

[0020] Similarly, picture C3is the motion-compensat-ed prmotion-compensat-ediction picture for encoding the picture B3. Note that the motion vector m23 is representative of the

amount of motion between pictures B2and B3. This is

in contrast to the prior art in which all motion vectors are calculated with respect to the same reference picture B1. In the present example, motion vector m23has the

value (υ,0). Picture B3is now encoded in the form of

difference picture D3.

[0021] With reference to Fig.2 again, the encoded pic-tures Dialong with the motion vectors m are stored on a storage medium 3 or transmitted through a transmis-sion channel. Subsequently, the original sequence of low-resolution pictures is decoded by the motion-com-pensated prediction decoder 4. Again, only the most rel-evant elements of this (MPEG) decoder are shown, i.e. an adder 41, a frame memory 42 and a motion-compen-sator 43 which receives the motion vectors m as pro-duced by the encoder.

[0022] After reconstructing the original low-resolution pictures, the high-resolution still picture is recursively created by the processing circuit 5. As shown in Fig.2, this processing circuit 5 comprises an up-sampler 51, a multiplier 52, an adder 53, a frame memory 54 and a motion compensator 55.

[0023] Fig.4 shows various pictures to illustrate the operation of the processing circuit. The pictures B1, B2

and B3are the decoded low-resolution pictures supplied by the prediction decoder 4. Apart from artefacts due with the imperfectness of the compression by the en-coder, they correspond with the pictures B1, B2and B3 shown in Figs. 1 and 3. Pictures E1, E2and E3are their versions in the high-resolution domain. They are sup-plied by up-sampler 51 by pixel repetition.

[0024] In a first iteration step, the processing circuit 5 outputs the first high-resolution picture G1and feeds it

into the frame memory 54. Because the first picture is an I-picture, the output picture G1is the same as input

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5 10 15 20 25 30 35 40 45 50 55 picture E1.

[0025] In a second iteration step, the next high-reso-lution picture E2and a motion-compensated previous

picture F2are added by adder 53. The

motion-compen-sated picture F2is obtained by shifting the stored picture G1two pixels to the right and one pixel upwards in

ac-cordance with motion vector m'12=(2,1) which is twice

the original motion vector m12. Picture G2is the result of this iteration step. The pixel values shown have been normalized, i.e. divided by 2 which is the number of pic-tures processed thus far. As can be seen, high-resolu-tion details start to appear in the vertical direchigh-resolu-tion. De-tails do not yet appear in the horizontal direction be-cause the original motion vector m12has a sub-pixel

component in the vertical direction only. The output pic-ture G2(without the normalization factor being applied)

is stored in frame memory 54.

[0026] In a third iteration step, the next high-resolution picture E3and a motion-compensated previous picture F3are added. The latter is obtained by shifting the stored

picture G2one pixel to the right in accordance with mo-tion vector m'23=(1,0). Picture G3is the result of this it-eration step. The pixel values shown are obtained after division by 3, which is the number of pictures processed thus far. As can be seen, high-resolution details now start to appear also in the horizontal direction, because the original motion vector m23has a sub-pixel

compo-nent in this direction.

[0027] The above described steps are repeated for each further picture in the sequence of decoded pic-tures. The more subsequent P-pictures are processed in this manner, the better the output picture will resemble the original object.

[0028] As will be appreciated, the invention offers the particular advantage that the motion vectors obtained in the encoding phase are also used in the still-picture cre-ation phase. It is not necessary to have another motion estimator. Neither is a memory for each picture required. Furthermore, the motion vectors refer to the immediate-ly preceding picture rather than to a fixed reference pic-ture. Because motion between successive pictures is relatively small, the probability of obtaining motion vec-tors with half-pixel accuracy (which is essential for res-olution doubling) is therefore considerably greater than in the prior art.

[0029] The invention also allows still pictures to be transmitted or stored as a sequence of compressed low-resolution pictures, which requires a moderate trans-mission or storage capacity. Widely available standard components (MPEG encoders and decoders) can be used, and the sequence of low-resolution pictures can optionally be reproduced in the form of motion video. [0030] In summary, a method and arrangement is dis-closed for creating a high-resolution still picture. A se-quence of lower-resolution pictures is subjected to mo-tion-compensated predictive encoding, preferably by an MPEG encoder producing an IPPP.. sequence of encod-ed pictures. The relatively small differences between

successive pictures, which are due to motion of the im-age sensor or motion in the scene, become manifest in motion vectors with sub-pixel accuracy. The high-reso-lution picture is then created from the decoded pictures and the motion vectors generated by the encoder. [0031] The invention is particularly applicable in elec-tronic still picture cameras with a storage medium. The MPEG encoder takes care of data compression, and the decoder also allows playback of the original moving vid-eo sequence.

Claims

1. A method of creating a high-resolution still picture, comprising the steps of:

receiving a sequence of lower-resolution pic-tures;

estimating motion in said sequence of lower-resolution pictures with sub-pixel accuracy; and

creating the high-resolution still picture from said sequence of lower-resolution pictures and said estimated motion;

characterized in that the method comprises the steps of:

subjecting the sequence of pictures to motion-compensated predictive encoding, thereby generating motion vectors representing motion between successive pictures of said sequence; decoding said encoded pictures; and

creating the high-resolution picture from said decoded pictures and the motion vectors gen-erated in said encoding step.

2. The method as claimed in claim 1, wherein the cre-ating step includes recursively adding, in the high-resolution domain, a current decoded picture to a previously created picture, said previously created picture being subjected to motion-compensation in accordance with the motion vector which is associ-ated with the current decoded picture.

3. The method as claimed in claim 1, further compris-ing the step of storcompris-ing the encoded pictures on a storage medium.

4. The method as claimed in claim 1, wherein the step of encoding the sequence of pictures comprises the use of an MPEG encoder which is arranged to pro-duce an IPPP.. sequence of encoded pictures. 5. A method of creating a high-resolution still picture

from a sequence of lower-resolution pictures re-ceived in the form of motion-compensated

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tively encoded pictures and motion vectors repre-senting motion between successive pictures of said sequence, comprising the steps of:

decoding said encoded pictures; and

creating the high-resolution picture from said decoded pictures and the received motion vec-tors.

6. The method as claimed in claim 5, wherein the cre-ating step includes recursively adding, in the high-resolution domain, a current decoded picture to a previously created picture, said previously created picture being subjected to motion compensation in accordance with the motion vector which is associ-ated with the current decoded picture.

7. The method as claimed in claim 5, wherein the se-quence of motion-compensated predictively encod-ed pictures and motion vectors is receivencod-ed in the form of an MPEG video bitstream comprising an IPPP.. sequence of encoded pictures.

8. An arrangement for creating a high-resolution still picture, comprising:

means (1) for receiving a sequence of lower-resolution pictures;

means for estimating motion in said sequence of lower-resolution pictures with sub-pixel ac-curacy; and

means (5) for creating the high-resolution still picture from said sequence of lower-resolution pictures and said motion vectors;

characterized in that the arrangement further comprises:

an encoder (2) for subjecting the sequence of pictures to motion-compensated predictive en-coding, including a motion estimator (24) for generating motion vectors representing motion between successive pictures of said sequence; a decoder (4) for decoding said encoded pic-tures;

the creating means (5) being arranged to create the high-resolution picture from said decoded pictures and the motion vectors generated by the encoder (2).

9. The arrangement as claimed in claim 8, wherein the creating means include means (53,54) for resively adding, in the high-resolution domain, a cur-rent decoded picture to a previously created picture, said previously created picture being subjected to motion compensation (55) in accordance with the motion vector which is associated with the current decoded picture.

10. The arrangement as claimed in claim 8, further comprising a storage medium (3) for storing the en-coded pictures.

11. The arrangement as claimed in claim 8, wherein the encoder (2) is an MPEG encoder which is arranged to produce an IPPP.. sequence of encoded pictures. 12. An arrangement for creating a high-resolution still

picture, comprising:

means for receiving a sequence of lower-reso-lution pictures in the form of motion-compen-sated predictively encoded pictures and motion vectors representing motion between succes-sive pictures of said sequence;

a decoder (4) for decoding said encoded pic-tures; and

means (5) for creating the high-resolution pic-ture from said decoded picpic-tures and the re-ceived motion vectors.

13. An image recording and reproducing apparatus, comprising an arrangement as claimed in claim 10, and further comprising an image sensor (1) for ob-taining the lower-resolution pictures.

Patentansprüche

1. Verfahren zum Erzeugen eines Hochauflösungs-Standbildes, wobei dieses Verfahren die nachfol-genden Verfahrensschritte umfasst:

- das Empfangen einer Sequenz von Bildern mit einer niedrigeren Auflösung;

- das Schätzen von Bewegung in der genannten Sequenz von Bildern mit einer niedrigeren Auf-lösung mit Sub-Pixelgenauigkeit; und

- das Erzeugen eines Standbildes mit hoher Auf-lösung aus der genannten Sequenz von Bildern mit niedrigerer Auflösung und mit der genann-ten geschätzgenann-ten Bewegung;

dadurch gekennzeichnet, dass das Verfahren die nachfolgenden Verfahrensschritte umfasst: - das Aussetzen der Sequenz von Bildern einer

bewegungskompensierten prädiktiven Codie-rung, wobei Bewegungsvektoren erzeugt wer-den, die eine Bewegung zwischen aufeinander folgenden Bildern der genannten Sequenz dar-stellen;

- das Decodieren der genannten codierten Bil-der; und

- das Erzeugen des Hochauflösungsbildes aus den genannten decodierten Bildern und den in dem genannten Codierungsschritt erzeugten

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5 10 15 20 25 30 35 40 45 50 55 Bewegungsvektoren.

2. Verfahren nach Anspruch 1, wobei der Erzeugungs-schritt die rekursive Addierung, in einer Hochauflö-sungsdomäne, eines aktuellen decodierten Bildes zu einem vorher erzeugten Bild umfasst, wobei das vorher erzeugte Bild einer Bewegungskompensati-on ausgesetzt wird, und zwar entsprechend dem Bewegungsvektor, der mit dem aktuellen decodier-ten Bild assoziiert ist.

3. Verfahren nach Anspruch 1, wobei dieses Verfah-ren weiterhin den VerfahVerfah-rensschritt der Speiche-rung der codierten Bilder auf einem Speichermedi-um Speichermedi-umfasst.

4. Verfahren nach Anspruch 1, wobei der Verfahrens-schritt der Codierung der Sequenz von Bildern die Verwendung eines MPEG-Codierers umfasst, der zum Erzeugen einer IPPP..-Sequenz codierter Bil-der vorgesehen ist.

5. Verfahren zum Erzeugen eines Hochauflösungs-Standbildes aus einer Sequenz von Niederauflö-sungsbildern, empfangen in Form bewegungskom-pensierter, prädiktiv codierter Bilder und aus Bewe-gungsvektoren, die Bewegung zwischen aufeinan-der folgenden Bilaufeinan-dern aufeinan-der genannten Sequenz dar-stellen, wobei dieses Verfahren die nachfolgenden Verfahrensschritte umfasst:

- das Decodieren der genannten codierten Bil-der; und

- das Erzeugen des Hochauflösungsbildes aus den genannten decodierten Bildern und den empfangenen Bewegungsvektoren.

6. Verfahren nach Anspruch 5, wobei der Erzeugungs-schritt eine rekursive Addierung, in der Hochauflö-sungsdomäne, eines aktuellen decodierten Bildes zu einem vorher erzeugten Bild umfasst, wobei das genannte vorher erzeugte Bild einer Bewegungs-kompensation entsprechend dem Bewegungsvek-tor ausgesetzt wird, der mit dem aktuellen decodier-ten Bild assoziiert ist.

7. Verfahren nach Anspruch 5, wobei die Sequenz be-wegungskompensierter prädiktiv codierter Bilder und Bewegungsvektoren in Form eines MPEG-Vi-deo-Bitstroms mit einer IPPP..-Sequenz codierter Bilder empfangen wird.

8. Anordnung zum Erzeugen eines Hochauflösungs-Standbildes, wobei diese Anordnung die nachfol-genden Elemente umfasst:

- Mittel (1) zum Empfangen einer Sequenz von Niederauflösungsbildern;

- Mittel zum Schätzen von Bewegung in der ge-nannten Sequenz von Niederauflösungsbil-dern mit Sub-Pixel-Genauigkeit; und

- Mittel (5) zum Erzeugen des Hochauflösungs-Standbildes aus der genannten Sequenz von Niederauflösungsbildern und den genannten Bewegungsvektoren;

dadurch gekennzeichnet, dass die Anordnung weiterhin die nachfolgenden Elemente umfasst: - einen Codierer (2) um die Sequenz von Bildern

einer bewegungskompensierten, prädiktiven Codierung auszusetzen, wobei dieser Codierer einen Bewegungsschätzer (24) aufweist zum Erzeugen von Bewegungsvektoren, die Bewe-gung zwischen aufeinander folgenden Bildern der genannten Sequenz darstellen;

- einen Decoder (4) zum Decodieren der ge-nannten codierten Bilder;

wobei die Erzeugungsmittel (5) vorgesehen sind zum Erzeugen des Hochauflösungsbildes aus den genannten decodierten Bildern und den von dem Codierer (2) erzeugten Bewegungsvektoren. 9. Anordnung nach Anspruch 8, wobei die

Erzeu-gungsmittel Mittel (53, 54) umfassen zum rekursi-ven Addieren, in der Hochauflösungsdomäne, ei-nes aktuellen decodierten Bildes zu einem vorher erzeugten Bild, wobei das vorher erzeugte Bild ei-ner Bewegungskompensation (55) ausgesetzt wird, und zwar entsprechend dem Bewegungsvektor, der mit dem aktuellen decodierten Bild assoziiert ist. 10. Anordnung nach Anspruch 8, weiterhin mit einem

Speichermedium (3) zur Speicherung der codierten Bilder.

11. Anordnung nach Anspruch 8, wobei der Codierer (2) ein MPEG-Codierer ist, der zum Erzeugen einer IPPP..-Sequenz codierter Bilder vorgesehen ist. 12. Anordnung zum Erzeugen eines

Hochauflösungs-Standbildes, wobei diese Anordnung die nachfol-genden Elemente umfasst:

- Mittel zum Empfangen einer Sequenz von Nie-derauflösungsbildern in Form bewegungskom-pensierter, prädiktiv codierter Bilder und Bewe-gungsvektoren, die Bewegung zwischen auf-einander folgenden Bildern der genannten Se-quenz darstellen;

- einen Decoder (4) zum Decodieren der ge-nannten codierten Bilder; und

- Mittel (5) zum Erzeugen des Hochauflösungs-bildes aus den genannten decodierten Bildern und den empfangenen Bewegungsvektoren.

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13. Bildaufzeichnungs- und -wiedergabeanordnung mit einer Anordnung nach Anspruch 10, und weiterhin mit einem Bildsensor (1) zum Erhalten der Nieder-auflösungsbilder.

Revendications

1. Procédé pour créer une image fixe de haute réso-lution, comprenant les étapes suivantes consistant à:

recevoir une séquence d'images de plus basse résolution;

estimer un mouvement dans ladite séquence d'images de plus basse résolution avec une précision de sous-pixel; et

créer l'image fixe de haute résolution à partir de ladite séquence d'images de plus basse ré-solution et dudit mouvement estimé;

caractérisé en ce que le procédé comprend les étapes suivantes consistant à:

soumettre la séquence d'images à un codage prédictif à compensation de mouvement, de ce fait générant des vecteurs de mouvement re-présentant un mouvement entre des images successives de ladite séquence;

décoder lesdites images codées; et

créer l'image de haute résolution à partir des-dites images décodées et des vecteurs de mouvement qui sont générés dans ladite étape de codage.

2. Procédé selon la revendication 1, dans lequel l'éta-pe de création comprend l'addition récursive, dans le domaine de haute résolution, d'une image déco-dée actuelle à une image précédemment créée, la-dite image précédemment créée étant soumise à une compensation de mouvement suivant le vec-teur de mouvement qui est associé à l'image déco-dée actuelle.

3. Procédé selon la revendication 1, comprenant en-core l'étape consistant à stocker les images codées sur un support de mémoire.

4. Procédé selon la revendication 1, dans lequel l'éta-pe consistant à coder la séquence d'images com-prend l'utilisation d'un codeur MPEG qui est agencé de manière à produire une séquence IPPP d'ima-ges codées.

5. Procédé pour créer une image fixe de haute réso-lution à partir d'une séquence d'images de plus bas-se résolution qui sont reçues sous forme d'images à codage prédictif à compensation de mouvement

et de vecteurs de mouvement représentant un mou-vement entre des images successives de ladite sé-quence, comprenant les étapes suivantes consis-tant à:

décoder lesdites images codées; et

créer l'image de haute résolution à partir des-dites images décodées et des vecteurs de mouvement reçus.

6. Procédé selon la revendication 5, dans lequel l'éta-pe de création comprend l'addition récursive, dans le domaine de haute résolution, d'une image déco-dée actuelle à une image précédemment créée, la-dite image précédemment créée étant soumise à une compensation de mouvement suivant le vec-teur de mouvement qui est associé à l'image déco-dée actuelle.

7. Procédé selon la revendication 5, dans lequel la sé-quence d'images à codage prédictif à compensa-tion de mouvement et de vecteurs de mouvement est reçue sous forme d'un train de bits vidéo MPEG comprenant une séquence IPPP d'images codées. 8. Montage pour créer une image fixe de haute

réso-lution, comprenant:

des moyens (1) pour recevoir une séquence d'images de plus basse résolution;

des moyens pour estimer un mouvement dans ladite séquence d'images de plus basse réso-lution avec une précision de sous-pixel; des moyens (5) pour créer l'image fixe de haute résolution à partir de ladite séquence d'images de plus basse résolution et desdits vecteurs de mouvement;

caractérisé en ce que le montage comprend en-core:

un codeur (2) pour soumettre la séquence d'images à un codage prédictif à compensation de mouvement, comprenant un estimateur de mouvement (24) pour générer des vecteurs de mouvement représentant un mouvement entre des images successives de ladite séquence; un décodeur (4) pour décoder lesdites images codées;

les moyens de création (5) étant agencés de manière à créer l'image de haute résolution à partir desdites images décodées et des vec-teurs de mouvement qui sont générés par le co-deur (2).

9. Montage selon la revendication 8, dans lequel les moyens de création comprennent des moyens (53, 54) pour l'addition récursive, dans le domaine de

(8)

5 10 15 20 25 30 35 40 45 50 55

haute résolution, d'une image décodée actuelle à une image précédemment créée, ladite image pré-cédemment créée étant soumise à une compensa-tion de mouvement (55) suivant le vecteur de mou-vement qui est associé à l'image décodée actuelle. 10. Montage selon la revendication 8, comprenant en-core un support de mémoire (3) pour stocker les images codées.

11. Montage selon la revendication 8, dans lequel le co-deur (2) est un coco-deur MPEG qui est agencé de ma-nière à produire une séquence IPPP d'images co-dées.

12. Montage pour créer une image fixe de haute réso-lution, comprenant:

des moyens pour recevoir une séquence ges de plus basse résolution sous forme d'ima-ges à codage prédictif à compensation de mou-vement et de vecteurs de moumou-vement repré-sentant un mouvement entre des images suc-cessives de ladite séquence;

un décodeur (4) pour décoder lesdites images codées; et

des moyens (5) pour créer l'image de haute ré-solution à partir desdites images décodées et des vecteurs de mouvement reçus.

13. Appareil d'enregistrement et de reproduction d'ima-ge, comprenant un montage selon la revendication 10, et comprenant encore un détecteur d'image (1) pour obtenir les images de plus basse résolution.

(9)
(10)
(11)
(12)

Figure

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References

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