Motion adaptive interpolation of television image sequences

• US 4,651,207 A
• Filed: 03/05/1985
• Issued: 03/17/1987
• Est. Priority Date: 03/05/1984
• Status: Expired due to Term

• Current Assignee: Ant Nachrichtentechnik GmbH
• Original Assignee: Ant Nachrichtentechnik GmbH
• Inventors: Musmann, Hans-Georg, Bergmann, Hans C.
• Primary Examiner(s): NOT, DEFINED
• Assistant Examiner(s): NOT, DEFINED
• Application Number:
  US06/708,458
• Time in Patent Office: 742 Days
• Field of Search: 358/105, 358/133, 358/135, 358/136, 364/518, 364/521
• US Class Current: 375/240.12
• CPC Class Codes: H04N 19/577 Motion compensation with bidirectional frame interpolation, i.e. using B-pictures

Abstract

In order to effect motion adaptive interpolation of nontransmitted television image sequences, each based on at least two transmitted television image sequences, the transmitted sequences are received and segmentally divided into stationary and moving components, and the displacement of the moving components is determined by picture elements. These operations are carried out by electronically segmentally dividing each sequence into background regions which are to become visible and background regions which are to become hidden due to the movement of each moving component and deriving characteristic segment information having four possible values; deriving a set of filter coefficients from the character segment information and from information obtained as a result of determining displacement; and applying the filter coefficients to a motion adaptive interpolation filter for causing the filter to generate the nontransmitted image sequences.

Claims

1. In a method for the motion adaptive interpolation of nontransmitted television image sequences, each based on at least two transmitted television image sequences, by receiving the transmitted sequences and segmentally dividing the received sequences into stationary and moving components, and determining the displacement of the moving components by picture elements, the improvement comprising:

electronically segmentally dividing each sequence into background regions which are revealed and background regions which are to become hidden due to the movement of each moving component and deriving characteristic segment information having four possible values;

deriving a set of filter coefficients from the character segment information and from information obtained by said step of determining; and

applying the filter coefficients to a motion adaptive interpolation filter for causing the filter to generate the nontransmitted image sequences.

2. A method as defined in claim 1 wherein said step of determining is carried out:

by recursively deriving estimated displacement values, each value being derived by combining a correction value with the previously derived estimated displacement value; and

by deriving the correction value by a mathematical division operation in which the divisor is the average of a first value obtained by cross-correlation of the currently received image sequence with a previously received image sequence, and a second value obtained by autocorrelation of the currently received image sequence.

3. A method as defined in claim 1 wherein the nontransmitted image sequences are reconstructions of image sequences previously eliminated from the transmitted sequences.

4. A method as defined in claim 3, carried out for removing flicker during playback of standard television images by increasing the image repetition rate in that the generated image sequences are displayed on a playback monitor between the transmitted image sequences, displayed in the standard manner.

5. A method as defined in claim 1 wherein the interpolated image sequences form a new image sequence with a converted standard with an image repetition rate which is different from the input image sequence.

6. A method as defined in claim 1 for the suppression of noise during playback of transmitted television image sequences.

7. A method as defined in claim 6 wherein the transmitted sequences are transmitted from a videorecorder.

8. A circuit arrangement including a motion adaptive interpolator for generating television image sequences from transmitted image sequences depicting a scene, each generated sequence being derived from at least two transmitted sequences and being inserted, at a video display terminal, between two of the transmitted sequences from which it is derived, said circuit arrangement being constructed to generate an output signal containing successive representations of successive picture elements of an image sequence being generated, with each picture element being representative of an element of the scene depicted by the transmitted sequences, and further comprising means for deriving, from transmitted image sequences, indications relating to the locus, on the associated image, of each successive picture element of a sequence being generated, which indications include a first set of locus indications representative of the difference between the locus of each picture element of the sequence being generated and the integral number of picture element positions in an estimated displacement of the scene element represented by that picture element between the sequence being generated and a transmitted sequence from which that sequence is being generated, and a second set of locus indications representative of the addition of the locus of each picture element of the sequence being generated and such integral number of picture element positions;

and said interpolator comprising;

a first image sequence memory connected to receive and store representations of the picture elements of a transmitted image sequence from which an image sequence is being generated and which precedes the image sequence being generated, said first image sequence memory having address inputs connected to receive the first set of locus indications and four data outputs for supplying representations of respective ones of four successive picture elements of the transmitted image sequence stored in said first memory;

a second image sequence memory connected to receive and store representations of the picture elements of a transmitted image sequence from which the image sequence is being generated and which follows the image sequence being generated, said second image sequence memory having address inputs connected to receive the second set of locus indications and four data outputs for supplying representations of respective ones of four successive picture elements of the transmitted image sequence stored in said second memory;

first and second bilinear interpolators each having four data inputs connected to said four data outputs of a respective one of said image sequence memories, two additional inputs connected to receive indications of any fractional part of each estimated displacement, and an output for supplying representations of a characteristic of each picture element of a sequence being generated;

two controllable coefficient evaluators each having a data input connected to said output of a respective one of said bilinear interpolators, a control input connected to receive an indication of the movement being experienced by the scene element depicted by each picture element of the image sequence being generated, and an output for supplying representations of the representations applied to its associated data input in dependence on the indications applied to its associated control input; and

summing means having summing inputs connected to said outputs of said coefficient evaluators and an output for providing a signal constituting the image sequence being generated.