Television display system with reduced line-scan artifacts

Abstract

A flat-field television image having reduced visibility of horizontal scan lines is generated by receiving first and second fields of interlaced video and progressively generating a scanned image within a time for one incoming field. The progressively scanned image contains interstitial lines between the lines of one field, and consequently the line-scan structure is made less visible, but the flicker rate is undesirably decreased. In order to increase the flicker rate, additional progressively scanned images are generated at a rate equal to or greater than the incoming field rate.

What is claimed is: 
     
       1. A method for producing a flat-field representation of a line-scanned image, said method comprising the steps of:   producing scanned lines of video signals each of which is representative of a line scan .Iadd.of one field of interlaced fields comprising a frame .Iaddend.of the image information, which scanned lines of video signals, if displayed, produce an objectionable line-scan structure;   storing at least one line of said scanned lines of video signals .Iadd.but substantially less than the number of scanned lines of video signals per field .Iaddend.to provide stored video;   .[.comparing.]. .Iadd.combining .Iaddend.said stored video with at least one temporally adjacent scanned line of video to produce an estimated value of the video which would be produced by a line-scan of said image between said stored and adjacent lines, thereby producing an estimated line of video;   time-compressing said stored, estimated and adjacent lines by a factor related to the quotient of a sum and the number of scanned lines of video per frame, where said sum is the sum of the number of said estimated lines and said scanned lines of video per frame; and   displaying .Iadd.non-interlaced .Iaddend.fields of video by progressive scanning of said scanned lines of video alternated with said estimated lines of video.Iadd., each of said progressively scanned non-interlaced fields being derived from only one of said interlaced fields, .Iaddend.whereby said objectionable line-scan structure is made less visible.   
     
     
       2. A method for producing a flat-field representation of a line-scanned image, said method comprising the steps of: producing scanned lines of composite color television signals each of which is representative of a line scan .Iadd.of one field of interlaced fields comprising a frame .Iaddend.of the image information, which scanned lines of composite color television signals, if displayed, produce an objectionable line-scan structure;   storing at least one line of said scanned lines of composite color television signals .Iadd.but substantially less than the number of scanned lines of composite television signals per field .Iaddend.to produce stored video;   .[.comparing.]. .Iadd.combining .Iaddend.said stored video with at least one temporally adjacent scanned line of television signals to produce an estimated value of the video which would be produced by a line-scan of said image between said stored and adjacent lines, thereby producing an estimated line of video.[., said comparing step further comprising the step of separating the luminance component from the chrominance component of said composite video.].;   time-compressing said stored, estimated and adjacent lines by a factor related to the quotient of a sum and the number of scanned lines of composite color television lines per frame, where said sum is the sum of the number of said estimated lines and said scanned lines per frame; and   displaying .Iadd.non-interlaced .Iaddend.fields of video by progressive scanning of said scanned lines of color television signals alternated with said estimated lines of video.Iadd., each of said progressively scanned non-interlaced fields being derived from only one of said interlaced fields, .Iaddend.whereby said objectionable line-scan structure is made less visible.   
     
     
       3. A method according to claim 2 further comprising the steps of delaying a .[.said.]. component of said composite signal to form first, second and third delayed component samples relatively delayed with respect to a current component sample; and   summing together weighted values of said composite .[.segment.]. .Iadd.signal .Iaddend.and at least some of said delayed samples to form an interpolated signal representative of said estimated lines of video.   
     
     
       4. A method according to claim 2 wherein said number of scanned line of video per frame is 525, said number estimated lines is 525 and said factor is two. 
     
     
       5. A television display for producing a flat-field representation of a line-scanned image from video signals representative of scanned-line image information .Iadd.organized in interlaced fields of a frame .Iaddend.comprising: delay means for storing at least one line of the scanned-line video signals .Iadd.but substantially less than the number of line-scanned video signals per field .Iaddend.to produce .Iadd.a .Iaddend.stored video signal;   estimating means coupled to said delay means and with the source of said scanned-line video signals for .[.comparing.]. .Iadd.combining .Iaddend.said stored video signal with at least one temporally-adjacent line of said scanned-line video signals to produce an estimated value of the video which would be produced by a line-scan of said image at a path physically between the paths scanned to produce said stored and adjacent video signals, thereby producing lines of estimated video signals;   time-compressing means coupled to said estimating means and to said delay means for time-compressing said stored, adjacent and estimated video signals by a factor related to the quotient of a sum and the number of scanned lines of scanned-line image information per frame, where said sum is the sum of the number of said estimated lines and said scanned lines of scanned-line video signals per frame.[.,.]..Iadd.; .Iaddend.and   display means coupled to said time-compression means for displaying fields of video by progressive scanning of said lines of estimated video alternated with lines of said scanned-line video signals.Iadd., each of said progressively scanned fields being derived from only one of said interlaced fields. .Iaddend. .[.   
     
     
       6.  A method for producing an image of a scene which is line-scanned in an interlaced manner for successively generating first and second fields of interlaced line-scan video signals each frame of which is representive of the scene, the method comprising the steps of: storing in a memory at least a full frame of said video signals;   displaying a frame of line-scan video signals from said memory in a progressive noninterlaced manner for decreasing the visibility of the line-scan structure of the image, whereby the flicker rate objectionably decreases; and   repeating said displaying step from old image information whereby the objectionable low flicker rate increases..]. .[.7. A method according to claim 6 further comprising the steps of time-compressing said video signals by a factor depending upon the number of said repetitions..]. .[.8. A method according to claim 7 wherein said factor is the sum of one plus the number of said repetitions..]. .[.9. A method according to claim 6 further comprising the steps of storing at least one of said line-scan video signals from said memory to produce a stored line of video; comparing said stored line of video with at least one spatially adjacent scanned line of video to produce an estimate of the value of the video which would be produced by a line scan of the scene between the lines of the frame, thereby producing estimated lines of video; and displaying said estimated lines of video alternately with said line-scan video signals from said memory for further decreasing the visibility of said line-scan   
     
     
        structure of the image..]. .[.10.  A television display apparatus for producing an image of a scene which is represented by first and second fields of interlaced lines of video signals comprising: memory means coupled to the source of video signals for controllably storing at least one frame of said video signals;   writing control means coupled to said memory means and to said source of video signals for controlling the writing of said video signals into said memory means for storing at least one full frame of said video signals in said memory means; and   reading control means coupled to said memory means for reading in a time-compressed manner from said memory means alternate odd and even lines of said video signals; and   display means coupled to said memory means and to said reading control means for progressively displaying said odd and even lines of video signals..]. .[.11. A method for producing an image of a scene which is line-scanned in an interlaced manner for successively generating first and second fields of interlaced line-scan video signals each frame of which is representative of the scene, the method comprising the steps of:   storing in a memory a field of said video signals to form stored video signals;   time-compressing said first video signals to form time-compressed first video signals;   time-compressing said stored video signals to form time-compressed stored video signals;   time-division multiplexing said time-compressed first and stored video signals together to produce multiplexed video signals; and   displaying said multiplexed video signals in a progressive noninterlaced manner for decreasing the visibility of the line-scan structure of the image..]. .[.12. A method according to claim 11 wherein said multiplexing step is performed on a line-to-line basis for creating alternate lines of said first and stored video signals..]. .[.13. A method for producing an image of a scene which is line-scanned in an interlaced manner for successively generating first and second fields of interlaced line-scanned video signals each frame of which is representative of the scene;   the method comprising the steps of:   storing in a memory at least a field of said video signals to form delayed line-scan video signals;   displaying a frame of line-scan video signals in a progressive noninterlaced manner alternating between lines of said video signals and lines of said delayed video signals whereby successive frames displayed   
     
     
        are comprised of even and odd adjacent fields..]. .Iadd.14.  An image display system, comprising: a source of an interlaced television signal organized in interlaced fields which occur successively in time, each of said fields of said interlaced television signal including a number of received lines;   converting means including a memory with a line storage capacity substantially less than the number of received lines in each of said fields of said interlaced television signal for generating a progressive television signal organized in successive fields from said interlaced television signal, each field of said progressive television signal including lines representative of said received lines of a respective field of said interlaced television signal alternating in time with interstitial lines derived from ones of said received lines of the same field of said interlaced television signal without contribution from another field of said interlaced television signal; and   display means responsive to said progressive television signal for scanning an image in non-interlaced fields, each of said scanned non-interlaced fields being derived from only one of said non-interlaced fields. .Iaddend. .Iadd.15. An image display system as recited in claim 14, wherein:   said converting means includes time-compressing means for producing said lines of said progressive television signal in time-compressed form in relation to said received lines of said interlaced television signal in which said lines of said progressive television signal have a duration less than the duration of said lines of said interlaced television signal; and   said display means scans said lines of said progressive television signal at a rate which is greater than the line rate of said interlaced   
     
     
        television signal. .Iaddend. .Iadd.16.  An image display system as recited in claim 15, wherein: said converting means includes estimating means including said memory for generating said interstitial lines;   said time-compressing means receives said received lines of said interlaced television signal and said interstitial lines for forming time-compressed versions thereof; and   said converting means includes inserting means for inserting said time-compressed versions of said interstitial lines in time between time compressed versions of said received lines. .Iaddend. .Iadd.17. An image display system as recited in claim 14, wherein:   said interstitial lines are representative of the average of respective pairs of said representative lines adjacent in time to said interstitial lines. .Iaddend. .Iadd.18. An image display system, comprising:   a source of an interlaced television signal organized in interlaced fields which occur successively in time, each field of said interlaced television signal including a number of scan-line video signals corresponding to respective scanning lines of an image;   memory means with a line storage capacity which is substantially less than the number of scan-line video signals in each of said fields of said interlaced television signal for storing said scan-line video signals of said interlaced television signal;   estimating means incorporating said memory means for generating, for each field of said interlaced television signal, estimated video signals corresponding to interstitial lines occurring in space between said scanning lines of said field of said interlaced television signal derived from scan-line video signals of the same field of said interlaced television signal;   display means for scanning an image in non-interlaced fields in response to said scan-line and estimated video signals, each of said scanned non-interlaced fields including scanning lines corresponding to the scanning lines of a respective one of said interlaced television signals and scanning lines corresponding to interstitial lines of the same field occurring alternately, in both time and space, in progressive fashion and   
     
     
        without contribution from another field. .Iaddend. .Iadd.19.  The image display system recited in claim 18 further including: time compression means coupled to said source of said interlaced television signal and to said estimating means for providing time-compressed versions of said scan-line and estimated video signals which have a duration less than the duration of said scan-line video signals of said interlaced television signal to said display means; and wherein   said display means scans said scanning lines of said non-interlaced fields in response to said time-compressed versions of said scan-line and estimated video signals at a rate greater than the rate of said scan-line video signals of said interlaced television signal. .Iaddend. .Iadd.20. The image display system recited in claim 18 wherein:   said estimating means comprises averaging means for averaging pairs of scan-line video signals of said interlaced television signal adjacent in time to respective ones of said estimated video signals. .Iaddend.   
     
     
        .Iadd.  .  The image display system recited in claim 18 wherein: said memory means delays said scan-line video signals of said interlaced television signal to produce a plurality of delayed versions of said scan-line video signals; and   said estimating means includes weighting means for weighting said delayed versions of said scan-line video signals to produce delayed and weighted versions of said scan-line video signals; and summing means for combining said scan-line video signals with delayed and weighted version of scan-line video signals to produce said estimated video signals. .Iaddend. .Iadd.22. The image display system recited in claim 18 wherein:   said line-scan video signals and said estimated video signals are composite color television signals including respective chrominance components and respective luminance components; and   said display means includes decoder means for separating said chrominance and luminance components from said line-scan video signals and estimated video signals. .Iaddend. .Iadd.23. An image display system, comprising:   a source of an interlaced television signal organized in interlaced fields which occur successively in time, each field of said interlaced television signal including a number of scan-line video signals corresponding to respective scanning lines of an image;   memory means with a line storage capacity which is substantially less than the number of scan-line video signals in each of said fields of said interlaced television signal for storing said scan-line video signals of said interlaced television signal;   estimating means incorporating said memory means for generating, for each field of said interlaced television signal, estimated video signals corresponding to interstitial lines occurring in space between respective pairs of said scanning lines of said field of said interlaced television signal by averaging respective pairs of scan-line video signals of the same field of said interlaced television signal;   time compression means coupled to said source of said interlaced television signal and to said estimating means for providing time-compressed versions of said scan-line and estimated video signals which have a duration less than the duration of said scan-line video signals of said interlaced television signal; and   display means for scanning an image in non-interlaced fields in response to said time-compressed versions of said scan-line and estimated video signals at a rate greater than the rate of said scan-line video signals of said interlaced television signal, each of said scanned non-interlaced fields including scanning lines corresponding to the scanning lines of a respective one of said interlaced television signals and scanning lines corresponding to interstitial lines of the same field occurring alternately, in both time and space, in progressive fashion and without   
     
     
        contribution from another field. .Iaddend. .Iadd.24.  An image display system, comprising: a source of an interlaced television signal organized in interlaced fields which occur successively in time, each field of said interlaced television signal including a number of scan-line video signals corresponding to respective scanning lines of an image, each of said scan-line video signals being a composite color television signal including chrominance and luminance components;   memory means with a line storage capacity which is substantially less than the number of scan-line video signals in each of said fields of said interlaced television signal for storing said scan-line video signals of said interlaced television signal;   estimating means incorporating said memory means for generating, for each field of said interlaced television signal, estimated video signals corresponding to interstitial lines occurring in space between said scanning lines of said field of said interlaced television signal derived from scan-line video signals of the same field of said interlaced television signal, each of said estimated video signals being a composite color television signal including chrominance and luminance components;   display means including decoder means for separating said chrominance and luminance components from said scan-line video signals and said estimated video signals and scanning means for scanning an image in noninterlaced fields in response to said chrominance and luminance components of said scan-line and estimated video signals, each of said scanned noninterlaced fields including scanning lines corresponding to the scanning lines of a respective one of said interlaced television signals and scanning lines corresponding to interstitial lines of the same field occurring alternately, in both time and space, in progressive fashion and without contribution from another field. .Iaddend.