Apparatus for discriminating a moving region and a stationary region in a video signal

• US 4,667,233 A
• Filed: 09/17/1985
• Issued: 05/19/1987
• Est. Priority Date: 09/17/1984
• Status: Expired due to Fees

• Current Assignee: NEC Corporation
• Original Assignee: NEC Corporation
• Inventors: Furukawa, Akihiro
• Primary Examiner(s): Britton, Howard W.
• Application Number:
  US06/777,033
• Time in Patent Office: 609 Days
• Field of Search: 358/140, 358/105, 358/11, 358/135, 358/136
• US Class Current: 375/240.12
• CPC Class Codes: G06T 2207/10016 Video; Image sequence
• CPC Class Codes: G06T 7/223 using block-matching
• CPC Class Codes: H04N 19/503 involving temporal prediction adaptive coding with adaptive selection between spatial and temporal predictive coding H04N19/107; adaptive coding with adaptive selection among a plurality of temporal predictive coding modes H04N19/109

Abstract

An apparatus for discriminating a region that contains motion from a region that does not contain motion in a video signal, particularly for use in an inter-frame predictive coding apparatus. The apparatus bridges across different portions of a moving region or of a stationary region to avoid small isolated regions of either type that would cause spurious responses by the encoding circuit and a resulting degradation of picture quality. The apparatus determines for each picture element a frame difference, which is the brightness difference for that picture element from one frame to the next. The picture elements are divided into a predetermined plurality of blocks. Then a first evaluation value is produced by an adder (14, 14'"'"'), which may be alternatively the sum of the absolute values of the frame differences in each block, or the number of picture elements within each block for which the absolute value of the frame difference is greater than a predetermined threshold. In certain embodiments (FIGS. 4 and 5), a comparator (15, 15'"'"') determines whether the first evaluation value exceeds a predetermined threshold, and in response outputs a first moving/stationary region signal. The first moving/stationary region signal is stored in a memory (22) and processed by a decision circuit (23) which generates a final moving/stationary region signal which has been compensated to eliminate errors due to noise. The compensation by the decision circuit can follow either of two alternative methods, namely, spatial correlation between a block and the neighboring blocks; or time correlation between the status of a given block at particular points in time. The final moving/stationary region information signal employed to control an encoding circuit. In other embodiments (FIGS. 10 and 11) the first evaluation value is weighted by weighting factors to produce a second evaluation value. The weighting is based on the first evaluation values of blocks that are close to the given block either in time sequence or in location.

Claims

1. An apparatus for discriminating a moving region and a stationary region in an input video signal which is divided into time frames, each time frame including a plurality of time fields, and spatially divided into a plurality of picture elements, a plurality of mutually adjacent blocks of picture elements being defined therein, comprising:

means for storing said input video signal for at least one field to deliver a delayed video signal;

means for extracting an amplitude difference for each of said picture elements between said delayed video signal and said input video signal;

means for summing the extracted amplitude differences for the picture elements belonging to each of a plurality of blocks to deliver a first evaluation value for each of said plurality of blocks;

means for comparing said first evaluation value with a predetermined value to deliver a first moving/stationary region signal for each block of said plurality of blocks; and

means for compensating said first moving/stationary region siganl for said each block in response to at least one other first moving/stationary region signal corresponding to a block adjacent to said each block to deliver a final moving/stationary region signal as an output of said apparatus.

2. An apparatus for discriminating a moving region and a stationary region in an input video signal which is divided into time frames, each time frame including a plurality of time fields, and spatially divided into a plurality of picture elements, a plurality of mutually adjacent blocks of picture elements being defined therein, comprising:

means for storing said input video signal for at least one field to deliver a delayed video signal;

means for extracting an amplitude difference for each of said picture elements between said delayed video signal and said input video signal;

means for summing the extracted amplitude differences for the picture elements belonging to each of a plurality of blocks to deliver a first evaluation value for each of said plurality of blocks;

means for comparing said first evaluation value with a predetermined value to deliver a first moving/stationary region signal for each block of said plurality of blocks; and

means for compensating said first moving/stationary region signal for said each block in response to at least one previous said first moving/stationary region signal for the same block to deliver a final moving/stationary region signal as an output of said apparatus.

3. An apparatus for discriminating a moving region and a stationary region in an input video signal which is divided into time frames, each time frame including a plurality of time fields, and spatially divided into a plurality of picture elements, a plurality of mutually adjacent blocks of picture elements being defined therein, comprising:

means for storing said input video signal for at least one field to deliver a delayed video signal;

means for determining an amplitude difference for each of said picture elements between said delayed video signal and said input video signal;

first comparing means for comparing said amplitude difference with a first predetermined value to deliver a significance signal for each of said picture elements when said amplitude difference is greater than said first predetermined value;

means for counting the number of significance signals for the picture elements belonging to each of said plurality of blocks;

second comparing means for comparing said number of said significance signals with a second predetermined value to deliver a first moving/stationary region signal for each block of said plurality of blocks; and

means for compensating said first moving/stationary region signal for said each block in response to at least one other first moving/stationary region signal corresponding to a block adjacent to said each block to deliver a final moving/stationary region signal as an output of said apparatus.

4. An apparatus for discriminating a moving region and a stationary region in an input video signal which is divided into time frames, each time frame including a plurality of time fields, and spatially divided into a plurality of picture elements, a plurality of mutually adjacent blocks of picture elements being defined therein, comprising:

means for storing said input video signal for at least one field to deliver a delayed video signal;

means for determining an amplitude difference for each of said picture elements between said delayed video signal and said input video signal;

first comparing means for comparing said amplitude difference with a first predetermined value to deliver a significance signal for each of said picture elements when said amplitude difference is greater than said first predetermined value;

means for counting the number of significance signals for the picture elements belonging to each of said plurality of blocks;

second comparing means for comparing said number of said significance signals with a second predetermined value to deliver a first moving/stationary region signal for each block of said plurality of blocks; and

means for compensating said first moving/stationary region signal for said each block in response to at least one previous said first moving/stationary region signal for the same block to deliver a final moving/stationary region signal as an output of said apparatus.

5. An apparatus for discriminating a moving region and a stationary region in an input video signal which is divided into time frames, each time frame including a plurality of time fields, and spatially divided into a plurality of picture elements, a plurality of mutually adjacent blocks of picture elements being defined therein, comprising:

means for storing said input video signal for at least one field to deliver a delayed video signal;

means for extracting an amplitude difference for each of said picture elements between said delayed video signal and said input video signal;

means for summing the extracted amplitude differences for the picture elements belonging to each of a plurality of blocks to deliver a first evaluation value for each block;

means for weighting said first evaluation value for each block and other said first evaluation values for blocks adjacent to said each block by respective predetermined weighting factors and for summing said weighted first evaluation values to produce a second evaluation value; and

means for comparing said second evaluation value with a predetermined value to deliver a moving/stationary region signal as an output of said apparatus.

6. An apparatus for discriminating a moving region and a stationary region in an input video signal which is divided into time frames, each time frame including a plurality of time fields, and spatially divided into a plurality of picture elements, a plurality of mutually adjacent blocks of picture elements being defined therein, comprising:

means for storing said input video signal for at least one field to deliver a delayed video signal;

means for determining an amplitude difference for each of said picture elements between said delayed video signal and said input video signal;

first comparing means for comparing said amplitude difference with a first predetermined value to deliver a significance signal for each of said picture elements when said amplitude difference is greater than said first predetermined value;

means for counting the number of significance signals for the picture elements belonging to each of said plurality of blocks to deliver a first evaluation value;

means for weighting said first evaluation value for each block and other said first evaluation values for blocks adjacent to said each block by respective predetermined weighting factors and for summing said weighted first evaluation values to produce a second evaluation value; and

second comparing means for comparing said second evaluation value with a second predetermined value to deliver a moving/stationary region signal as an output of said apparatus.

7. An apparatus for discriminating a moving region and a stationary region in an input video signal which is divided into time frames, each time frame including a plurality of time fields, and spatially divided into a plurality of picture elements, a plurality of mutually adjacent blocks of picture elements being defined therein, comprising:

means for storing said input video signal for at least one field to deliver a delayed video signal;

means for extracting an amplitude difference for each of said picture elements between said delayed video signal and said input video signal;

means for summing the extracted amplitude differences for the picture elements belonging to each of a plurality of blocks to deliver at a given time a first evaluation value for each of said plurality of blocks;

means for weighting said first evaluation value for each block by weighting a plurality of said first evaluation values for said each block delivered at other times than said given time by respective weighting factors and by summing said weighted first evaluation values to produce a second evaluation value; and

means for comparing said second evaluation value with a predetermined value to deliver a moving/stationary region signal as an output of said apparatus.

8. An apparatus for discriminating a moving region and a stationary region in an input video signal which is divided into time frames, each time frame including a plurality of time fields, and spatially divided into a plurality of picture elements, a plurality of mutually adjacent blocks of picture elements being defined therein, comprising:

means for storing said input video signal for at least one field to deliver a delayed video signal;

means for determining an amplitude difference for each of said picture elements between said delayed video signal and said input video signal;

first comparing means for comparing said amplitude difference with a first predetermined value to deliver a significance signal for each of said picture elements when said amplitude difference is greater than said first predetermined value;

means for counting the number of significance signals for the picture elements belonging to each of said plurality of blocks to deliver a first evaluation value at a given time;

means for weighting said first evaluation value for each block by weighting a plurality of said first evaluation values for said each block delivered at times other than said given time by respective weighting factors and by summing said weighted first evaluation values to produce a second evaluation value; and

second comparing means for comparing said second evaluation value with a second predetermined value to deliver a moving/stationary region signal as an output of said apparatus.

9. An apparatus for discriminating a moving region and a stationary region in an input video signal which is divided into time frames, each time frame including a plurality of time fields, and spatially divided into a plurality of picture elements, a plurality of mutually adjacent blocks of picture elements being defined therein, comprising:

means for delaying said input video signal by at least one field period to deliver a delayed video signal;

means for calculating an amplitude difference for each picture element by subtracting said delayed video signal from said input video signal;

means for computing a first value for each of said blocks in response to said amplitude differences for each picture element contained in each respective block; and

means for determining whether each block is a moving region or a stationary region by taking a correlation of said first values for blocks adjacent to said block to deliver a second value indicating whether said block is a moving region or a stationary region.

10. An apparatus for discriminating a moving region and a stationary region in an input video signal which is divided into time frames, each time frame including a plurality of time fields, and spatially divided into a plurality of picture elements, a plurality of mutually adjacent blocks of picture elements being defined therein, comprising:

means for delaying said input video signal by at least one field period to deliver a delayed video signal;

means for calculating an amplitude difference for each picture element by subtracting said delayed video signal from said input video signal;

means for computing a first value for each of said blocks in response to said amplitude differences for each picture element contained in each respective block; and

means for determining whether each block is a moving region or a stationary region by taking a time transition correlation of said first value of said block to deliver a second value indicating whether said block is a moving region or a stationary region.