System for reducing beat type impairments in a TV signal

DETAILED DESCRIPTION We claim: 1.
A system for reducing impairments in real time from a television transmission comprising digitizing frames to produce digitized frames containing pixels each having their respective original grey scale intensity value (v) digitized to a corresponding digitize grey scale value (v.
sub.
(i,j)), processing said digitized frame for each pixel for which said impairments are to be reduced by applying spatial filter to a block of said pixels containing said pixel (P.
sub.
(i,j)) then being processed by determining the pixel (P.
sub.
max) in said block having the maximum grey scale intensity value (v.
sub.
(max)) and the pixel (P.
sub.
min) in said block having the minimum grey scale intensity value (v.
sub.
(min)) and comparing v.
sub.
(max) minus v.
sub.
(min) to a threshold value (v.
sub.
(T)), if v.
sub.
(max) -v.
sub.
(min) >v.
sub.
(T) a resultant value v.
sub.
(R-i,j) for the pixel P.
sub.
(i,j) being processed is said value (v.
sub.
(i,j)) for the pixel being processed and if v.
sub.
(max) -v.
sub.
(min) .
notgreaterthan.
v.
sub.
(T) the resultant value v.
sub.
(R-i,j) for the pixel P.
sub.
(i,j) being processed is determined by finding a weighted average intensity value v.
sub.
(av.
) of the pixels in the group after applying a minimum weighting value (W.
sub.
(min)) to v.
sub.
(max) and to v.
sub.
(min) and using the weighted average value v.
sub.
(av.
) to define the resultant intensity value v.
sub.
(R-i,j) for the pixel P.
sub.
(i,j) being processed, and reconstructing said frames to provide corrected frames using applied values v.
sub.
(a-i,j) derived from said resultant value v.
sub.
(R-i,j) as grey scale value for its respective pixel in said reconstructed frame.
2.
A system as defined in claim 1 wherein said minimum weighting value W.
sub.
(min) is zero (0).
3.
A system as defined in claim 1 wherein said block is defined by an odd number of adjacent pixels of between three to seven pixels along a row of pixels.
4.
A system as defined in claim 1 wherein said block is defined by an odd number of adjacent pixels of between three and seven pixels along a column of pixels