Facsimile and static presentation processing – Facsimile – Specific signal processing circuitry
Patent
1988-08-01
1990-01-30
Chin, Tommy P.
Facsimile and static presentation processing
Facsimile
Specific signal processing circuitry
359140, 359167, H04N 701
Patent
active
048977160
DESCRIPTION:
BRIEF SUMMARY
BACKGROUND OF THE INVENTION
This invention relates to a method of and apparatus for the display of conventional video signals at high field rate without complex pre-processing.
Conventional television systems, particularly those based on a field rate of 50 Hz, tend to suffer from flicker in large bright areas of the picture. Such flicker can be especially noticeable on large area displays, when it is perceived by the viewer's peripheral vision. Large area flicker can be reduced by increasing the field rate at the display; one simple method of achieving this would be to display each picture at twice the normal rate. This requires the use of a system of storage into which incoming signals are written and from which they are read twice over at twice the conventional scanning frequency. This simple method would remove large area flicker but would also provoke an annoying judder on moving objects, whose edges and fine detail would be portrayed as having discontinuous movement.
However, the display of moving parts of the picture in accordance with conventional scanning standards does not give rise to appreciable judder, assuming that the original scene was similarly scanned, e.g. in a conventional television camera. Moreover, the presence of movement will tend to prevent the perception of large area flicker.
SUMMARY OF THE INVENTION
We have appreciated that large area flicker might be removed without incurring the penalty of movement judder if moving areas of the picture are displayed conventionally, e.g. at the 625/50/2:1 standard, while stationary areas are displayed at a higher field rate, e.g. at 625/100/2:1.
With this arrangement the two types of area have differing numbers of lines per unit time, giving rise to differing displayed intensities. In a second embodiment of the invention this is overcome by displaying moving areas with a 625/50/1:1 standard.
All these figures are those appropriate to a 625 line 50 field per second based system by means of which it is convenient to illustrate the invention but the invention is not limited thereto.
The invention is more particularly defined in the appended claims.
BRIEF DESCRIPTION OF THE DRAWINGS
The invention will be described by way of example with reference to the drawings in which:
FIG. 1 is a vertical/temporal diagram showing possible positions of scanned lines and those displayed in areas of motion and in stationary areas;
FIG. 2 is a schematic block diagram of a video display device operating in accordance with the principles of FIG. 1 and embodying the invention;
FIG. 3 is a simplified version of the circuit diagram of FIG. 2;
FIGS. 4 and 5 are vertical/temporal diagrams similar to FIG. 1 showing lines displayed in the stationary mode and in the motion mode respectively in a second embodiment of the invention;
FIGS. 6 and 7 illustrate simple algorithms for generating the content of the output lines shown in the stationary and motion modes respectively as defined by FIGS. 4 and 5;
FIG. 8 illustrates an arrangement of field stores for providing access to the signals for the algorithms of FIGS. 6 and 7;
FIG. 9 illustrates the timing of the field store cycles and the operation of the switches S1 to S5 in the circuit of FIG. 8;
FIG. 10 is a circuit diagram of the temporal interpolator used in the second embodiment;
FIG. 11 is a circuit diagram of the time re-distributor used in association with the circuit of FIG. 10;
FIG. 12 is a circuit diagram of the spatial interpolator and tiem re-distributor of the second embodiment;
FIG. 13 is a circuit diagram of a possible form of cross-fader circuit; and
FIG. 14 is a timing diagram illustrating the timing of line store cycles and the operation of switches S6 to S8.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
We have appreciated that to implement a display based on the above concept successfully, it may be necessary to provide a number of facilities and solve a number of problems. These may be listed as follows:
(a) It is necessary to distinguish between stationary and moving areas in the picture. A n
REFERENCES:
patent: 4057835 (1977-11-01), Kinuhata et al.
patent: 4635114 (1987-01-01), Wendland et al.
patent: 4731648 (1988-03-01), Bernard et al.
patent: 4731651 (1988-03-01), Matsumoto et a.
patent: 4745458 (1988-05-01), Hirano et al.
patent: 4785351 (1988-11-01), Ishikawa
Drewery John O.
Jones Arthur H.
British Broadcasting Corporation
Chin Tommy P.
Kostak Victor R.
O'Connell Robert F.
LandOfFree
Method and apparatus for adaptively displaying video signals does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Method and apparatus for adaptively displaying video signals, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Method and apparatus for adaptively displaying video signals will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-1926837