Luminance/color signal separation filter

Claim 2

A luminance/color signal separation filter comprising: converter means for sampling an analog composite video signal at a frequency four times as large as a color subcarrier frequency for converting the same into a digital signal (1); and vertical/horizontal filter means including delay means, (61, 62, 71, 72, 73) multiplier means (91, 92), adder means (81, 81) and subtractor means (101, 102) for removing luminance signal components included in said digital signal outputted from said converter means, said vertical/horizontal filter means including means for changing filter characteristics by employing a sampled point included in said analog composite signal and sampled values of points upwardly or downwardly separated by two horizontal scanning lines from said sampled point and precedingly or subsequently separated by two sampling points from said sampled point in which color subcarrier phases are inverted (61, 62, 71, 72, 73).

Claim 3

A luminance/color signal separation filter comprising: converter means for sampling an analog composite video signal at a sampling frequency four times as large as a color subcarrier frequency for converting the same into a digital signal (1); a horizontal filter including first delay means (24), first adder means (81), first subtractor means (101) and first multiplier means (91) for outputting high frequency components of a horizontal luminance signal based on said digital signal outputted from said converter means; a vertical filter including second delay means (23), second adder means (82), second subtractor means (102) and second multiplier means (92) for outputting high frequency components of a vertical luminance signal based on said digital signal outputted from said converter means; and switching means for switching said horizontal filter and said vertical filter in response to said digital signal outputted from said converter means based on a sampled point on a screen and sampled values of points vertically or horizontally in the vicinity of said sampled point on said screen in which color subcarrier phases are inverted (16).

Claim 4

A luminance/color signal separation filter comprising: converter means for sampling an analog composite video signal at a sampling frequency four times as large as a color subcarrier frequency for converting the same into a digital signal (1); a horizontal filter including first delay means (24), first adder means (81), first subtractor means (101) and first multiplier means (91) for outputting high frequency components of a horizontal luminance signal based on said digital signal outputted from said converter means; a vertical filter including second delay means (23), second adder means (82), second subtractor means (102) and second multiplier means (92) for outputting high frequency components of a vertical luminance signal based on said digital signal outputted from said converter means; and switching means for switching said horizontal filter and said vertical filter in response to said digital signal outputted from said converter means based on a sampled point on a screen and sampled values of points vertically or horizontally in the vicinity of said sampled point on said screen in which color subcarrier phases are inverted (16).

Claim 5

A luminance/color signal separation filter comprising: converter means for sampling an analog video signal at a sampling frequency four times as large as a color subcarrier frequency for converting the same into a digital signal (1); sample signal generator means receiving said digital signal outputted from said converter means for outputting a separated signal, a first sample signal advanced by two sampled points from said separated signal, a second sample signal delayed by two sampled points from said separated signal, a third sample signal advanced by two horizontal scanning periods from said separated signal and a fourth sample signal delayed by two horizontal scanning periods from said separated signal (20, 21, 22, 23, 24) first signal outputting means receiving said first and second sample signals for outputting a TH signal as difference value of the horizontal direction (104, 142); second signal outputting means receiving said third and fourth sample signals outputted from said sample signal generator means for outputting a TV signal as difference value of the vertical direction (103, 141); comparator means comparing said signal of high frequency components of said vertical luminance signal outputted from said first signal outputting means and said signal of high frequency components of said horizontal luminance signal outputted from said second signal outputting means for outputting said first signal when said signal of high frequency components of said vertical luminance signal is smaller than said signal of high frequency components of said horizontal luminance signal as well as outputting said second signal when said signal of high frequency components of said horizontal luminance signal is smaller than said signal of high frequency components of said vertical luminance signal (15); horizontal color signal generator means-for outputting a horizontal color signal based on said first and second sample signals and said separated signal outputted from said sample signal generator means (81, 91, 101); vertical color signal generator means for outputting a vertical color signal based on said third and fourth sample signals and said separated signal outputted from said sample signal generator means (82, 92, 102); switching means receiving said horizontal color signal outputted from said horizontal color signal generator means, said vertical color signal outputted from said vertical color signal generator means and said first and second signals outputted from said comparator means for outputting said vertical color signal as the color signal upon receiving said first signal as well as outputting said horizontal color signal as the color signal upon receiving said second signal (16); and luminance signal generator means for outputting a luminance signal based on said color signal outputted from said switching means and said separated signal outputted from said sample signal generator means (5).

Claim 6

A luminance/color signal separation filter comprising: converter means for sampling an analog video signal at a sampling frequency four times as large as a color subcarrier frequency for converting the same into a digital signal (1); sample signal generator means receiving said digital signal outputted from said converter means for outputting a separated signal, a first sample signal advanced by two sampled points from said separated signal, a second sample signal delayed by two sampled points from said separated signal, a third sample signal advanced by two horizontal scanning periods from said separated signal and a fourth sample signal delayed by two horizontal scanning periods from said separated signal (20, 21, 22, 23, 24) first signal outputting means receiving said first and second sample signals for outputting a TH signal as difference value of the horizontal direction (104, 142); second signal outputting means receiving said third and fourth sample signals outputted from said sample signal generator means for outputting a TV signal as difference value of the vertical direction (103, 141); comparator means comparing said signal of high frequency components of said vertical luminance signal outputted from said first signal outputting means and said signal of high frequency components of said horizontal luminance signal outputted from said second signal outputting means for outputting said first signal when said signal of high frequency components of said vertical luminance signal is smaller than said signal of high frequency components of said horizontal luminance signal as well as outputting said second signal when said signal of high frequency components of said horizontal luminance signal is smaller than said signal of high frequency components of said vertical luminance signal (15); horizontal color signal generator means-for outputting a horizontal color signal based on said first and second sample signals and said separated signal outputted from said sample signal generator means (81, 91, 101); vertical color signal generator means for outputting a vertical color signal based on said third and fourth sample signals and said separated signal outputted from said sample signal generator means (82, 92, 102); switching means receiving said horizontal color signal outputted from said horizontal color signal generator means, said vertical color signal outputted from said vertical color signal generator means and said first and second signals outputted from said comparator means for outputting said vertical color signal as the color signal upon receiving said first signal as well as outputting said horizontal color signal as the color signal upon receiving said second signal (16); and luminance signal generator means for outputting a luminance signal based on said color signal outputted from said switching means and said separated signal outputted from said sample signal generator means (5).

Claim 7

A luminance/color signal separation filter in accordance with claim 3, wherein said sample signal generator means includes: first delay means delaying said digital signal outputted from said converter means by two horizontal scanning periods for outputting said third sample signal (20), fourth delay means delaying said third sample signal outputted from said first delay means by two sampled points for outputting said separated signal (22), second delay means delaying said separated signal outputted from said fourth delay means by two horizontal scanning periods for outputting said second sample signal (24) , third delay means delaying said digital signal outputted from said converter means by two sampled points for outputting said first sample signal (21), and fifth delay means delaying said separated signal outputted from said fourth delay means by two sampled points for outputting said fourth sample signal (23).

Claim 8

A luminance/color signal separation filter in accordance with claim 3, wherein said horizontal color signal generator means includes: first adder means for outputting the sum of said first and second sample signals outputted from said sample signal generator means (81), first multiplier means for multiplying the summed signal outputted from said first adder means by 1/4 (91), third multiplier means for multiplying said separated signal outputted from said sample signal generator means (93), and first subtractor means for outputting difference between said multiplied signal outputted from said first multiplier means and the multiplied signal outputted from said third multiplier means as said horizontal color signal (101).

Claim 9

A luminance/color signal separation filter in accordance with claim 3, wherein said vertical color signal generator means includes: second adder means for outputting the sum of said third and fourth sample signals outputted from said sample signal generator means (82), second multiplier means for multiplying the summed signal outputted from said second adder means by 1/4 (92), and second subtractor means for outputting difference between the multiplied signal outputted from said second multiplier means and the multiplied signal outputted from said third multiplier means (102).

Claim 10

A luminance/color signal separation filter in accordance with claim 3, wherein said first signal generator means includes: third subtractor means for outputting difference between said first sample signal and said second sample signal generated from said sample signal generator means (103), and first absolute value operator means operating the absolute value of the difference signal outputted from said third subtractor means for outputting said TH signal (141).

Claim 11

A luminance/color signal separation filter in accordance with claim 3, wherein said second signal generator means includes: fourth subtractor means for outputting difference between said third sample signal and said fourth sample signal outputted from said sample signal generator means (104), and second absolute value operator means operating the absolute value of the difference signal outputted from said fourth subtractor means for outputting said TV signal (142).

Claim 12

A luminance/color signal separation filter in accordance with claim 3, wherein said second signal generator means includes: fifth subtractor means for outputting difference between said first sample signal and said second sample signal outputted from said sample signal generator means (103), third absolute value operator means for operating the absolute value of the difference signal outputted from said fifth subtractor means (141), constant generator means for generating a predetermined constant (17), and third adder means for outputting the sum of said absolute value signal generated from said third absolute value operator means and the predetermined constant signal outputted from said constant generator means as said signal of said high frequency components of said vertical luminance signal (18).

Claim 13

A luminance/color signal separation filter in accordance with claim 3, wherein said first signal generator means includes: fifth subtractor means for outputting difference between said third sample signal and said fourth sample signal outputted from said sample signal generator means (104), and fourth absolute value operator means operating the absolute value of the difference signal outputted from said fifth subtractor means for outputting said signal of high frequency components of said horizontal luminance signal (142).

Claim 14

A luminance/colour signal separation filter in which a digital composite video signal having a component modulated at an even submultiple of the digital sampling frequency is separated by; comparing a sample value (S(i,j)) with one or more comparison sample values (S(i-2,j), S(i+2,j), S(i,j-2), S(i,j+2)) from nearby parts of the video scene, the comparison sample(s) having been taken at instant(s) when the modulation value applied to the said component was 180° out of phase from its value when the said sample value was taken, thereby to derive a value (C) for the said modulated component; and comparing the values (C) thus obtained for the said modulated component with the values (S) of the digital composite signal to derive values (Y) for the other component, characteristed in that sample values separated in a first direction are compared to derive a first value (H C ) for the said modulated component and a first value (T H ) for the difference in the said other component between sample values, and sample values separated in a second direction transverse to the first are compared to derive a second value (V C ) for the said modulated component and a second value (T V ) for the difference in the said other component between sample values, the value (H C or V C ) for the modulated component associated with the lower absolute value ( |T H | or |T V |) of the difference in the said other component being selected as the value (C) for the modulated component.

Claim 15

A luminance/colour signal separation filter in which a digital composite video signal having a component modulated at an even submultiple of the digital sampling frequency is separated by; comparing a sample value (S(i,j)) with one or more comparison sample values (S(i-2,j), S(i+2,j), S(i,j-2), S(i,j+2)) from nearby parts of the video scene, the comparison sample(s) having been taken at instant(s) when the modulation value applied to the said component was 180° out of phase from its value when the said sample value was taken, thereby to derive a value (C) for the said modulated component; and comparing the values (C) thus obtained for the said modulated component with the values (S) of the digital composite signal to derive values (Y) for the other component, characteristed in that sample values separated in a first direction are compared to derive a first value (H C ) for the said modulated component and a first value (T H ) for the difference in the said other component between sample values, and sample values separated in a second direction transverse to the first are compared to derive a second value (V C ) for the said modulated component and a second value (T V ) for the difference in the said other component between sample values, the value (H C or V C ) for the modulated component associated with the lower absolute value ( |T H | or |T V |) of the difference in the said other component being selected as the value (C) for the modulated component.