Method of and device for estimating the extent of motion in a picture element of a television picture

Claim 1

A method of estimating the extent of motion in a picture element (pixel) of a television picture, said method being based on picture signal value comparisons between pixels in successive television pictures in which, starting with a present pixel in a present television picture, the picture signal value of said present pixel is compared with that of a corresponding pixel in a previous and/or subsequent television picture, and with that of a plurality of surrounding pixels in the present television picture, and in which the extent of motion in said present pixel is established dependent on a number of comparison results exceeding or not exceeding a threshold value, said number being obtained by means of the picture signal value comparisons, characterized in that said method comprises the steps: comparing the difference between the picture signal values of said present pixel and said corresponding pixel with a first threshold value, motion being indicated by said difference exceeding said first threshold value; comparing the difference between the picture signal values of said present pixel and each of said surrounding pixels with a second threshold value, motion only being indicated by all of said differences exceeding said second threshold value; storing the results of the above comparing steps as a first and a second comparison result signifying no motion and motion, respectively, for the pixels of the television picture; repeating the above comparing and storing steps for a sub-region of a number of pixels surrounding said present pixel thereby forming a matrix of first and second comparison results; separately determining the number of first and second comparison results indicating no motion and motion and dividing each of the four determined numbers by the number of pixels in said sub-region; comparing the two determined numbers for the first comparison results with a first threshold number and comparing the two determined numbers for the second comparison results with a second threshold number; and deciding the extent of motion at said present pixel dependent on the combinations of the first and the second threshold numbers be exceeded or not exceeded by said determined numbers.

Claim 2

A method of estimating the extent of motion in a picture element (pixel) of a television picture, said method being based on picture signal value comparisons between pixels in successive television pictures in which, starting with a present pixel in a present television picture, the picture signal value of said present pixel is compared with that of a corresponding pixel in a previous and/or subsequent television picture, and with that of a plurality of surrounding pixels in the present television picture, and in which the extent of motion in said present pixel is established dependent on a number of comparison results exceeding or not exceeding a threshold value, said number being obtained by means of the picture signal value comparisons, characterized in that said method comprises the steps: comparing the difference between the picture signal values of said present pixel and said corresponding pixel with a first threshold value, motion being indicated by said difference exceeding said first threshold value; comparing the difference between the picture signal values of said present pixel and each of said surrounding pixels with a second threshold value, motion only being indicated by all of said differences exceeding said second threshold value; storing the results of the above comparing steps as a first and a second comparison result signifying no motion and motion, respectively, for the pixels of the television picture; repeating the above comparing and storing steps for a sub-region of a number of pixels surrounding said present pixel thereby forming a matrix of first and second comparison results; separately determining the number of first and second comparison results indicating no motion and motion and dividing each of the four determined numbers by the number of pixels in said sub-region; comparing the two determined numbers for the first comparison results with a first threshold number and comparing the two determined numbers for the second comparison results with a second threshold number; and deciding the extent of motion at said present pixel dependent on the combinations of the first and the second threshold numbers be exceeded or not exceeded by said determined numbers.

Claim 7

A device for estimating the extent of motion in a picture element (pixel) of a television picture, said estimation being based on picture signal value comparisons between pixels in successive television pictures in which, starting with a present pixel in a present television picture, the picture signal value of said present pixel is compared with that of a corresponding pixel in a previous and/or subsequent television picture, and with that of a plurality of surrounding pixels in the present television picture, and in which the extent of motion in said present pixel is established dependent on a number of comparison results exceeding or not exceeding a threshold value, said number being obtained by means of the picture signal value comparisons, said device comprising at least one memory device for storing or delaying the picture signal values of the pixels of a television picture, and at least a first and a second signal comparison-and-threshold circuit coupled to the memory device for performing the picture signal value comparisons between said present pixel, said corresponding pixel and the plurality of surrounding pixels, respectively, characterized in that said device further comprises: a further memory device which is coupled to outputs of at least the first and second signal comparison-and-threshold circuits for storing at least the first and second comparison results, respectively, per pixel for a sub-region of a plurality of pixels surrounding said present pixel, said further memory device having at least a first and a second group of a number of outputs associated with the matrix of the pixels of the sub-region; a first and a second accumulator circuit coupled, respectively, to said first and second groups of outputs of said further memory device, for, each time, accumulating the number of pixels signifying no motion and signifying motion, respectively; and third and fourth comparison-and-threshold circuits coupled, respectively, to outputs of said first and second accumulator circuits, operating in accordance with said relation, at least one output of the third comparison-and-threshold circuit and one output of the fourth comparison-and-threshold circuit conveying the combination as a code.

Claim 8

A device for estimating the extent of motion in a picture element (pixel) of a television picture, said estimation being based on picture signal value comparisons between pixels in successive television pictures in which, starting with a present pixel in a present television picture, the picture signal value of said present pixel is compared with that of a corresponding pixel in a previous and/or subsequent television picture, and with that of a plurality of surrounding pixels in the present television picture, and in which the extent of motion in said present pixel is established dependent on a number of comparison results exceeding or not exceeding a threshold value, said number being obtained by means of the picture signal value comparisons, said device comprising at least one memory device for storing or delaying the picture signal values of the pixels of a television picture, and at least a first and a second signal comparison-and-threshold circuit coupled to the memory device for performing the picture signal value comparisons between said present pixel, said corresponding pixel and the plurality of surrounding pixels, respectively, characterized in that said device further comprises: a further memory device which is coupled to outputs of at least the first and second signal comparison-and-threshold circuits for storing at least the first and second comparison results, respectively, per pixel for a sub-region of a plurality of pixels surrounding said present pixel, said further memory device having at least a first and a second group of a number of outputs associated with the matrix of the pixels of the sub-region; a first and a second accumulator circuit coupled, respectively, to said first and second groups of outputs of said further memory device, for, each time, accumulating the number of pixels signifying no motion and signifying motion, respectively; and third and fourth comparison-and-threshold circuits coupled, respectively, to outputs of said first and second accumulator circuits, operating in accordance with said relation, at least one output of the third comparison-and-threshold circuit and one output of the fourth comparison-and-threshold circuit conveying the combination as a code.