Computer graphics processing and selective visual display system – Display peripheral interface input device
Reexamination Certificate
1998-06-18
2001-07-10
Jankus, Almisa R. (Department: 2674)
Computer graphics processing and selective visual display system
Display peripheral interface input device
C345S004000
Reexamination Certificate
active
06259429
ABSTRACT:
This invention relates to multi-channel visual display apparatus.
Multi-channel visual display apparatus is known. Such apparatus is used in simulators/trainers for aircraft flight, ship's bridge, vehicle driving, large and small bore weapons, and in entertainment/information/advertising such for example as video walls.
The known multi-channel visual display apparatus utilises raster or calligraphic scan techniques. The apparatus is viewed by one or more observers and it is such that each individual display channel covers a designated field of view in relation to each display and an observer's viewing position. The displayed field of view for each individual display channel is arranged so that together the display channels provide the appearance of one continuous display which is free from discontinuities in picture geometry, brightness or colour at the boundaries.
The presentation of displayed field of view data can be provided by a graphics computer or a television source. The observer or observers view the multi-channel display as a projection on a front or rear projection screen, or directly on the face of a monitor. Alternatively, viewing is effected from projectors or TV monitors, through optical collimating devices such as collimating mirrors and/or lenses.
In multi-channel visual display apparatus, it is desirable to create an effect in which the data from the various channels are optically, mechanically and electronically aligned and adjusted so as to create the effect of a continuous signal display without noticeable geometric, brightness or colour mis-matches at the common boundaries between individual displays. These boundaries can either be butt joined or blended into each other over a few degrees of field of view overlap, or leave a small gap. In order to assist in geometric, brightness and colour matching, known apparatus employs micro computer technology incorporated in a remote control unit, whereby a maintenance engineer can remotely adjust each channel whilst observing the display.
When addressing the problem of matching adjacent display channels in terms of their colour chromaticity, current known practice is to ensure that the cathode ray tubes in adjacent displays are from the same manufacturer and are of the same type number. If monitors and projectors of different types and designs are used, for example liquid crystal display projectors and 3-cathode ray tube projectors, then current known practice is for their phosphor type numbers/colour filters to be the same. This is not always possible without incurring major design changes to the equipment. Other methods which are currently used are optical correction filters and, if liquid cooling or coupling is employed between cathode ray tube and lens, to add colour correction dyes to the liquid.
WO 92/08319 describes multi-channel display apparatus with a separate brightness adjustment control for each primary colour of each display channel. A primary colour is displayed in adjacent display channels with the same drive signal and the appropriate channel brightness adjustment controls are adjusted to minimise the brightness difference between the adjacent channels. This is then repeated for the other primary colour or colours. This procedure will enable a reasonable brightness match to be obtained between adjacent channels of a multi-channel display, but will not provide colour continuity across the boundary between adjacent channels unless the adjacent channel primary colours are inherently well matched.
An aim of the present invention is to provide multi-channel visual display apparatus having electronic means for compensating and correcting for colour mis-matching between adjacent channels.
Accordingly, in one non-limiting embodiment of the present invention there is provided multi-channel visual display apparatus comprising electronic means which is such that adjacent visual displays in a multi-channel display configuration are matched in colour in 2-and 3-primary colour systems.
The apparatus of the invention may be one in which the electronic means utilises additive mixing of red, green and blue video signals within each channel in order to achieve the matching. Alternatively, the apparatus may be one in which the electronic means utilises subtractive mixing of red, green and blue video signals in order to achieve the matching.
The apparatus of the invention may be one in which mixing of colour drive signals is in the form:
R
Drive
=R
IN
+S.G
IN
+T.B
IN
G
Drive
=U.R
IN
+G
IN
+V.B
IN
B
Drive
=W.R
IN
+X.G
IN
+B
IN
where S, T, U, V, W and X are constants.
The apparatus of the invention may alternatively be one in which mixing of colour drive signals is in the form:
R
Drive
=R
IN
+S.G
IN
+T.B
IN
G
Drive
=U.R
IN
+G
IN
+V.B
IN
B
Drive
=W.R
IN
+X.G
IN
+B
IN
where S, T, U, V, W and X are variables.
The variables may be a function of the position within a channel picture. The variables may be a function of horizontal and/or vertical scan timing. The variables may be controlled by a television camera viewing display channels. The variables may alternatively be controlled by a 3-primary colour sensor viewing display channels.
The apparatus of the invention may utilise raster scan formats and calligraphic scan formats.
The apparatus of the invention may be used with two or more projectors including liquid crystal display projectors, cathode ray tube projectors and light valve projectors.
The apparatus may utilise real image displays and collimated displays.
The apparatus of the invention may include television or graphics monitors.
The apparatus of the invention may include sensing means for sensing required correction values for the additive mixing or the subtractive mixing, the sensing means utilizing a 3-colour television camera or a 3-colour sensor, or other sensor providing colour information.
The apparatus of the invention may include tracking and adjustment means for tracking and adjusting the sensing of the required correction values in accordance with horizontal and vertical timing scan signals.
The apparatus of the invention may be applied to 2-colour projector and television/graphics monitor displays.
The apparatus of the invention may be such that the colour mis-matching in an edge-butted or blended multi-channel display is addressed by pre-selection of cathode ray tubes or by optical correction means.
The colour matching between adjacent displays may be achieved by electronic means by cross-mixing pre-determined percentages of video signals of the three primary colours of red, green and blue within a channel in such a way as to reposition any or all three corners in that display's colour triangle's corners to new x-y coordinates to coincide or at least move closer to the corners of any adjacent channel's colour triangle.
To achieve the shift of either one or all of the red, green and blue corners in the colour triangle of a particular channel's display, each primary colour's input signal has specific percentages of the other input signals added to it, according to the equations below.
R
out
=R
in
+p
rg
.G
in
+p
rb
.B
in
G
out
=p
gr
.R
in
+G
in
+p
gb
.B
in
B
out
=p
br
.R
in
+p
bg
.G
in
+B
in
where p
rg
. . . p
bg
are the colour mixing percentages, which may be constants or vary with position in the channel, and R
out
etc are the corrected drive signals to the channel's display device (CRT/LCD etc).
This cross-mixing of primary colours can be employed in all channels as required to achieve best colour match. It will be appreciated that in order to maintain colour match over a range of luminance levels, the mixing should be done at a point in the signal chain where the signal is linear with brightness, otherwise the mixing percentages should be gamma corrected in the same way as the signals.
The above described technique can be employed in display devices employing only two primary colours, examples of such displ
Iandiorio & Teska
Jankus Almisa R.
SEOS Displays Limited
Tran Henry N.
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