Video signal processing circuit
First Claim
1. A video signal processing circuit for performing error correction and error concealment on input video signal sample data, some of which contain errors and at least some of which are free of errors, comprising:
- error correcting means for correcting at least some of said errors and providing the resulting error corrected sample data, along with error flags indicating any sample data still containing errors at an output of said error correcting means;
one-dimensional error concealment means supplied with said error corrected sample data for performing one-dimensional error concealment using sample data which are on the same line as the sample data indicated to contain error,two-dimensional error concealment means supplied with output data from said one-dimensional error concealment means along with said error flags from said error correcting means, and operative for performing error concealment of said sample data indicated by said error flags to contain errors using other sample data in peripheral and/or time displaced relation to said sample data indicated to contain error, said one-dimensional error concealment means and said two-dimensional error concealment means together having a plurality of error concealment operating modes; and
operating mode selecting means for selecting one of said error concealment operating modes in dependence upon the state of the error flags for said peripheral and/or time displaced sample data.
1 Assignment
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Accused Products
Abstract
A video signal processing circuit carries out error correction, error concealment and weighted mean processing sequentially on video signals reproduced by a video tape recorder. One and two dimensional error concealment modes are provided respectively utilizing sample data on the same line as erroneous sample data to be concealed, and sample data in peripheral and/or time displaced relation to the erroneous sample data. One of a plurality of error concealment modes is selected depending upon the state of error flags for the peripheral and/or time displaced sample data. In certain advantageous embodiments, original sample data for which a gray code has been set, is compared with error concealed data and the original sample data is output in place of the error concealed data where such comparison indicates that the difference between the two is within a predetermined acceptance threshold.
Weighted mean sample data processing provides the capability of producing a first field of a video signal from a second field thereof by summing sample data from a plurality of lines of the second field to form the signals of the first field. In certain advantageous embodiments, the signals of the second field are multiplied by selectably variable coefficients, the selection of which is based on a detection that at least one of the line signals of the second field is outside an effective image information portion thereof.
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Citations
17 Claims
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1. A video signal processing circuit for performing error correction and error concealment on input video signal sample data, some of which contain errors and at least some of which are free of errors, comprising:
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error correcting means for correcting at least some of said errors and providing the resulting error corrected sample data, along with error flags indicating any sample data still containing errors at an output of said error correcting means; one-dimensional error concealment means supplied with said error corrected sample data for performing one-dimensional error concealment using sample data which are on the same line as the sample data indicated to contain error, two-dimensional error concealment means supplied with output data from said one-dimensional error concealment means along with said error flags from said error correcting means, and operative for performing error concealment of said sample data indicated by said error flags to contain errors using other sample data in peripheral and/or time displaced relation to said sample data indicated to contain error, said one-dimensional error concealment means and said two-dimensional error concealment means together having a plurality of error concealment operating modes; and operating mode selecting means for selecting one of said error concealment operating modes in dependence upon the state of the error flags for said peripheral and/or time displaced sample data. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. A video signal processing circuit for performing error correction and error concealment on input video signal sample data, some of which contain errors and at least some of which are free of errors, comprising:
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error correcting means for correcting at least some of said errors and providing the resulting error corrected sample data, along with error flags indicating any sample data still containing errors at an output of said error correcting means, and error concealment means supplied with said error-corrected sample data provided at said output and said error flags for performing error concealment of said sample data which are indicated by said error flags to contain errors using other sample data which are in peripheral and/or time displaced relation to said sample data indicated by said error flags to still contain errors; said error concealment means having a plurality of error concealment operating modes and including selectable recursive replacement error concealment means for error-concealing said sample data indicated to contain error by replacing said sample data with said other sample data which has replaced sample data indicated to contain error, counting means for producing a count signal representing the number of times that the other sample data has been used to conceal error, and selecting means for selecting one of said error concealment operating modes in dependence upon the state of the error flags for said peripheral and/or time displaced sample data, said selecting means being operative to select the recursive concealment means to error-conceal said sample data indicated to contain error based upon the count signal. - View Dependent Claims (10, 11, 12, 13, 14, 15, 16)
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17. A video signal processing circuit for performing error correction and error concealment on input video signal sample data, some of which contain errors and at least some of which are free of errors, comprising:
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error correction means for correcting at least some of said errors with the use of a product code employing at least a first and a second series of an error correction code of the input sample data and providing the resulting error corrected sample data, along with error flags indicating any sample data still containing errors at an output of said error correction means, said error correction means comprising gray flag producing means for setting a gray flag of the input sample data when the error correction capability of the error correction means using the second series of the error code is exceeded, and error concealment means supplied with said error corrected sample data provided at said output and said error flags for performing error concealment of said sample data which are indicated by said error flags to still contain errors using other sample data which are in peripheral and/or time displaced relation to said sample data indicated by said error flags to still contain errors, said error concealment means having a plurality of error concealment operating modes and including means for selecting one of said error concealment operating modes in dependence upon the state of the error flags for said peripheral and/or time displaced sample data; said error concealment means further including; comparison means for comparing the original sample data with error concealed data produced by the error concealment means to produce a difference signal representing a difference therebetween, and original sample data selection means for selecting the original sample data to be output in place of the error concealed data where the difference signal is within a predetermined acceptance threshold and the gray flag of said original sample data has been set.
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Specification