Claims
- 1. A digital chrominance separating and processing system for enabling the digital reproduction of the four color fields of a composite color television signal from a selectively stored single color frame or field, wherein the chrominance signal is incompletely extracted from the stored video as at given color edges of the video picture, the combination comprising;
- digital chrominance conditioning means for receiving the extracted chrominance and for digitally rotating the phase thereof from the nominal on alternate repetitive reproductions of the stored video, the degree of chrominance de-saturation at the color edges of the television picture being commensurate with said rotation; and
- digital-recombining means for reconstituting the reproductions with blending color edges of the video picture on alternate reproductions.
- 2. The system of claim 1 wherein the conditioning means partially de-saturates the chrominance signal of the reproductions a selected degree by corresponding selective digital rotation of the chrominance signal.
- 3. The system of claim 2 wherein the phase is selectively rotated within a range of zero to 90.degree..
- 4. The system of claim 3 further including;
- means for digitally separating the luminance signal from the stored video;
- said chrominance signal being rotated relative to the luminance signal;
- said means for reconstituting including adder means for summing the luminance and the phase rotated chrominance to combine both frames of partially de-saturated chrominance with no visually noticeable saturation changes between frames.
- 5. The system of claim 4 wherein said digital chrominance conditioning means comprises a digital transversal filter with odd symmetry which rotates the phase of all frequency components of the chrominance signal 90.degree. over a given range of frequencies.
- 6. The system of claim 5 wherein the digital transversal filter advances the phase of the chrominance signal 90.degree. in the first frame, and retards the phase thereof 90.degree. in the alternate frame.
- 7. The system of claim 5 wherein the digital transversal filter rotates the phase of the chrominance signal 90.degree. with selected sign in the first frame, and in the alternate frame rotates the phase thereof 90.degree. with the same sign and then inverts the phase of the latter signal by 180.degree..
- 8. The system of claim 5 wherein said digital transversal filter further includes;
- at least three serially coupled one-sample period delays;
- first subtractor means coupled across the first and last one-sample delays;
- second subtractor means coupled after the first and before the last one-sample delay;
- multiplier means coupled to respective subtractor means;
- adder means coupled to the multiplier means for generating a chrominance signal selectively rotated 90.degree.; and
- inverting stage means coupled to the adder means for passing the selectively rotated chrominance signal in the first frame, and for inverting the signal 180.degree. in an alternate frame, said combining means being coupled to the inverting stage means and to the luminance signal.
- 9. The system of claim 1 wherein the time period is equal to a color frame and the phase is rotated within a range of zero to 180.degree..
- 10. The system of claim 9 further including;
- digital filter means for receiving the stored video signal and for digitally separating the chrominance signal therefrom;
- said digital chrominance conditioning means being coupled to the filter means for digitally rotating the phase of the extracted chrominance signal selectively from the nominal during alternate frames to optimize the degree of desaturation thereof at said color edges where incomplete chrominance separation occurs; and
- digital combining means coupled to the conditioning means for digitally reconstituting the successive frames of the composite color television signal to visually optimize the de-saturated chrominance at the color edges.
- 11. The system of claim 10 wherein;
- said digital filter means includes means for providing a one horizontal line delayed wideband signal;
- said chrominance conditioning means comprises a digital multiply-by-two means coupled to the bandpass filter for providing no output therefrom in the first non-inverted frame, and for digitally doubling the chrominance signal prior to passing same in the alternate inverted frame; and
- said combining means comprises subtractor means which passes the wideband signal in the non-inverted frame, and subtracts the doubled chrominance signal from the wideband signal in the inverted frame.
- 12. The system of claim 11 including;
- means for generating an invert enable signal;
- wherein the digital multiply-by-two means includes latching means responsive to the presence and absence of the invert enable signal to enable and disable the output thereof on successive frames, and wire connections shifted by one bit to provide the chrominance doubling process.
- 13. The system of claim 10 wherein;
- said ditital filter means includes a digital comb filter for separating the chrominance signal, and a digital bandpass filter coupled to the comb filter for passing the frequency band occupied by the chrominance information;
- digital means coupled to the comb filter and the bandpass filter for digitally separating a luminance signal from the stored video signal;
- said conditioning means comprises digital inverting means for selectively rotating the phase of the chrominance relative to the luminance signal to generate the selected de-saturation; and
- said combining means digitally re-constitutes the chrominance and luminance within the composite color television signal.
- 14. The system of claim 13, wherein;
- said inverting means comprises a digital inverter circuit for passing the chrominance signal from the bandpass filter in the first frame, and inverting the chrominance signal by 180.degree. prior to passing same in the alternate frame; and
- said combining means is coupled to receive the non-inverted and inverted chrominance signals, and the luminance signal.
- 15. The system of claim 13 wherein;
- said inverting means comprises a digital transversal filter with odd symmetry which rotates the phase of all frequency components of the chrominance signal 90.degree. with respect to the luminance signal over a given range of frequencies; and
- said digital combining means is disposed to receive the chrominance and the luminance signals.
- 16. The system of claim 15 wherein said digital transversal filter advances the phase of the chrominance signal 90.degree. in the first frame, and retards the phase thereof 90.degree. in the alternate frame.
- 17. The system of claim 15 wherein said digital transversal filter advances the phase of the chrominance signal in the first frame, and in the alternate frame advances the phase thereof 90.degree. and then inverts the phase of the latter signal by 180.degree..
- 18. The system of claim 15 wherein said digital transversal filter retards the phase of the chrominance signal 90.degree. in the first frame, and in the alternate frame retards the phase thereof 90.degree. and then inverts the phase of the latter signal by 180.degree..
- 19. The system of claim 1 wherein the time period is equal to a field, wherein the chrominance signal is selectively rotated 90.degree. in each of the successive four playbacks of the stored field.
- 20. The system of claim 19 wherein the stored video signal is formed of single fields;
- said digital inverting means further includes a digital inverter circuit, and a digital transversal filter with odd symmetry, selectively coupled with respect to the chrominance signal on successive fields to effect the 90.degree. phase rotation therebetween on four successive playbacks of the field.
- 21. The system of claim 20 wherein;
- the digital transversal filter is coupled to the bandpass filter; and
- the circuit further includes digital switch means selectively intercoupling the chrominance signal with respect to the transversal filter and the inverter circuit to provide the four playbacks of the stored field with the 90.degree. phase rotation of the chrominance signal in the successive playbacks.
- 22. The system of claim 21 wherein the digital switch means further includes;
- a first digital switch having switch inputs numbers two and three and coupled at its output to the inverter circuit;
- a second digital switch having switch inputs one, two, three and four and coupled at its output to the digital combining means;
- said inverter circuit being connected to the number two and three inputs of the second digital switch;
- wherein in the first playback of the stored field, the number one input of the digital switch is coupled directly to the bandpass filter to pass the chrominance signal to the combining means with zero phase rotation;
- in the second playback of the field, the number two input of the first digital switch is coupled between the transversal filter and the number two input of the second digital switch via the inverter circuit to rotate the chrominance +270.degree.;
- in the third playback, the number three input of the first digital switch is coupled to the third input of the second digital switch via the inverter circuit to rotate the chrominance +180.degree.; and
- in the fourth playback, the number four input of the second digital switch is coupled to the transversal filter to rotate the chrominance +90.degree., thereby providing the four fields of the composite color television signal.
- 23. The system of claim 22 wherein the first and second digital switches are intercoupled to provide phase rotations of zero, -90.degree., -180.degree., -270.degree. for the four playbacks respectively of the stored field.
- 24. A process for digitally reproducing both frames of a composite color television signal from a signal stored field or frame, wherein the chrominance signal has been incompletely extracted from the stored video signal at the vertical transitions of the television picture, comprising the steps of;
- digitally conditioning the phase of the extracted chrominance signal to provide a selected condition of chrominance desaturation in given reproduced frames of the composite color television signal at said vertical transitions of the picture; and
- digitally re-combining the frames to generate the composite color television signal with visually improved variation in chrominance saturation at the vertical transitions of the television picture.
- 25. The process of claim 24 wherein the step of digitally conditioning further includes;
- digitally rotating the phase of the chrominance signal selectively from the nominal during playback to optimize the degree of chrominance de-saturation at the vertical transitions.
- 26. The process of claim 25 wherein the phase is digitally rotated 0.degree. in one frame and 180.degree. on the alternate frame.
- 27. The process of claim 25 wherein the phase is rotated +90.degree. in one frame, and -90.degree. in the alternate frame.
- 28. The process of claim 25 wherein the phase is rotated 90.degree. with selected sign in one frame, and in the alternate frame is rotated 90.degree. with the selected sign and then inverted 180.degree..
- 29. The process of claim 25 further including;
- providing a one horizontal line delayed wideband signal;
- wherein the step of digitally rotating includes;
- passing the wideband signal in one frame;
- doubling the chrominance signal in the alternate frame; and
- subtracting the doubled chrominance signal from the wideband signal during the alternate frame.
- 30. In a digital chrominance separating and processing system for digitally reproducing a composite color television signal from a selectively stored color frame or field, including filter means for separating the chrominance signal from the stored video, and re-combining means for reconstituting the composite color television signal, the improvement comprising;
- digital circuit means for digitally effecting an inversion of the separated chrominance on alternate repetitive reproductions of the stored video.
- 31. The system of claim 30 wherein the digital circuit means digitally rotates te chrominance during selected repetitive reproductions to effect said inversion.
- 32. The system of claim 31 wherein the digital rotation in selected reproductions defines a predetermined chrominance de-saturation commensurate with a visual likeness between frames at said color edges.
Parent Case Info
This is a continuation of the application Ser. No. 763,251, filed Jan. 26, 1977 and now abandoned.
US Referenced Citations (1)
Number |
Name |
Date |
Kind |
4007486 |
Inaba et al. |
Feb 1977 |
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Continuations (1)
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Number |
Date |
Country |
Parent |
763251 |
Jan 1977 |
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