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Claims  |
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I claim:
1. Apparatus for color conversion of an input video signal, said input
video signal representing a plurality of frames defining a moving image,
comprising:
a. a first circuit path having first function means for color modifying
said input video signal according to a first predetermined function,
thereby producing a first color converted signal;
b. a second circuit path controlled independently of said first path,
comprising second function means for providing video color conversion
according to a second predetermined function, in combination with area
modifying means for video transformation which provides modification of an
area of the image defined by a video signal, said second function means
and said area modifying means being operatively combined to transform said
input video signal into a second area-modified color converted signal; and
c. combining means for combining said first and second signals.
2. The apparatus as described in claim 1, wherein said area modifying means
comprises an area signal generator for generating a video area signal
corresponding to said area, and a transfer function circuit for modifying
any video signals as a function of said area signal.
3. The apparatus as described in claim 2, wherein said area signal
generator comprises means for generating an area signal corresponding to a
moving area.
4. The apparatus as described in claim 2, wherein said area modifying means
has a transfer function of 0 which is applied to video signals which
represent images outside of said area and a predetermined constant
transfer function which is applied to said video signals which represent
images within said area.
5. The apparatus as described in claim 2, wherein said area signal
generator generates an area video signal representative of a soft edged
area.
6. The apparatus as described in claim 3, wherein said area signal
generator is controllable to generate a moving area video signal having
soft boundaries.
7. The apparatus as described in claim 1, comprising a plurality of primary
modifying paths, each of such primary paths having a plurality of
subpaths, at least one of said subpaths of each primary path containing a
respective one of said second function means for modifying video signals
according to a respective second function in combination with a said area
modifying means for jointly producing an area modified color converted
subpath signal, summing means for summing the outputs of said subpaths of
each primary path to provide primary color converted signals, and input
means for inputting path signals to each primary path, said path signals
being derived from said input video signal.
8. The apparatus as described in claim 7, wherein each of said second
function means is controllable for controlling the said respective second
function.
9. The apparatus as described in claim 7, wherein each of said primary
paths comprises a subpath having a respective first function means for
modifying said path signals according to a respective first function.
10. The apparatus as described in claim 9, wherein each of said first and
second function means contains logic circuitry for receiving digital
control signals, whereby each of said respective functions is controllable
in discrete steps.
11. The apparatus as described in claim 9, wherein each of said function
means contains analog control circuitry for enabling variation of each of
said functions.
12. The apparatus as described in claim 7, wherein each of said area
modifying means comprises an area signal generator, each of said area
signal generators being controllable to generate a respective area video
signal corresponding to a respective area of the image represented by said
path signals.
13. The apparatus as described in claim 10, comprising color program data
input means for inputting color program data to selected ones of said
function means.
14. The apparatus as described in claim 7, wherein said function means are
controllable by data inputted thereto, and comprising color program data
input means for inputting color program data to selected ones of said
function means.
15. The apparatus as described in claim 14, comprising storage means for
storing color program data and area signals inputted to said selected
function means and to corresponding ones of said area modifying means.
16. The apparatus as described in claim 7, wherein said primary paths
comprise a Luminance path, a Red path and a Blue path, and said primary
path is adjustable to pass said inputted video signals in an unchanged
state.
17. The apparatus as described in claim 12, wherein each of said area
generators comprises means for moving its respective area.
18. The apparatus as described in claim 7, comprising three of said primary
paths for generating signals containing information translatable to
standard Luminance, Red and Blue TV signals.
19. The apparatus as described in claim 7, wherein said primary paths
comprise a Luminance path, a Red path and a Blue path and said input means
inputs common video signals to said Red path and said Blue path, and
comprising a first color function circuit for first color conversion of
said common inputted video signals.
20. The apparatus as described in claim 7, wherein said input means
comprises a primary color conversion circuit for color conversion of said
input video signal prior to said primary paths.
21. The apparatus as described in claim 4, wherein said area modifying
transfer function varies gradually from 0 to said constant at the
boundaries of said area.
22. The apparatus as described in claim 1, wherein said first circuit path
comprises a circuit for producing a continuous converted signal without
area modification.
23. A method for color conversion of video signals, comprising:
a. color converting said video signals according to a first function of
grey level alone to produce a first color converted signal;
b. performing upon said video signals the combined operation of color
converting according to a second function which is independent of said
first function and area modifying to modify an area of the image defined
by said video signals, to produce an area modified color converted signal;
and
c. combining said first color converted signal and said area modified color
converted signal to produce a composite color converted video signal
representing one or more frames having modified color conversion within a
selected area.
24. The method as described in claim 23, wherein said area modifying
comprises generating a video area signal corresponding to a selected area,
and area modifying video signals in accordance with an area transfer
function derived from said video area signal.
25. The method as described in claim 24, wherein said area transfer
function is substantially 0 corresponding to portions of said video
signals outside of said area and a predetermined constant corresponding to
portions within said area.
26. The method as described in claim 24, wherein said generated video area
signal corresponds to a moving area.
27. The method as described in claim 24, wherein said video area signal
generating step comprises generating a soft edged area signal.
28. The method as described in claim 24, comprising determining a portion
of the image defined by said video signals for color conversion, and
selecting the boundaries of said selected area to be outside of said
portion.
29. The method as described in claim 28, comprising choosing said second
function so that said combined operation color converts only video signals
corresponding to said determined portion, whereby no color conversion
takes place at said area boundaries.
30. The method as described in claim 28, comprising predetermining the
movement of a given image portion of said video signals over a
predetermined number of frames, and selecting said area boundaries to
embrace said movement.
31. The method as described in claim 23, wherein said second function is
negative at least in part.
32. The method as described in claim 23, wherein said composite signal
represents a first primary color signal, and synchronously generating at
least one additional respective like primary color signal.
33. The method as described in claim 32, wherein the generating of each of
said primary color signals comprises generating a plurality of respective
color converted signals and summing said plurality of signals.
34. The method as described in claim 33, comprising generating respective
area signals and area modifying selected ones of said plurality of color
converted signals with said area signals.
35. The method as described in claim 33, comprising controlling the
function by which each of said plurality of signals is color converted.
36. The method as described in claim 35, comprising generating color
program data representative of said function by which each of said
plurality of signals is color converted, and carrying out said controlling
in accordance with said program data.
37. The method as described in claim 36, comprising generating said program
data in successive steps, and editing and storing said program data and
said area signals.
38. The method as described in claim 32, wherein said first primary color
signal is a Red signal, an additional primary color signal is a Blue
signal, and comprising generating a Luminance signal from said video
signals.
39. The method as described in claim 38, wherein said generating of said
Luminance signal involved modification of said video signals with a
transfer function which is only a constant.
40. The method as described in claim 39, comprising first color converting
black and white video signals according to a predetermined color program
to generate said video signals.
41. Apparatus for selective color conversion of a video signal representing
a changing image, comprising:
a. means for modifying said video signal by continuously color converting
said video signal in accordance with a first function and modifying a
selected area of said signal in accordance with a second function, to
generate a color converted area modified video signal;
b. means for obtaining a Luminance video signal from said video signal; and
c. means for summing said color converted area modified video signal and
said Lumiance video signal.
42. The apparatus as described in claim 41, wherein said modifying means
comprises means for generating at least two independently color converted
signals and means for combining said at least two color converted signals.
43. The apparatus as described in claim 42, comprising three primary paths
for generating respectively said Luminance signal and two color converted
signals, and wherein each of said primary paths for producing color
converted primary signals comprises a plurality of subpaths for producing
color converted subpath signals and a summer for summing said subpath
signals.
44. The apparatus as described in claim 41, wherein said modifying means
comprises a single path, and comprising program data input means for
inputting to said modifying means a plurality of color conversion data
signals and at least an area signal, whereby said means color converts as
a function of said color conversion data signals and modifies said
selected area as a function of said area signal.
45. The apparatus as described in claim 43, wherein each of said subpaths
comprises a controllable transfer function circuit for modifying the video
signal inputted thereto by a selected function.
46. The apparatus as described in claim 43, comprising a plurality of area
signal generators, and wherein at least a plurality of said subpaths
comprise area modifying circuits in combination with respective ones of
said area signal generators for modifying selected areas in said subpath
circuits.
47. The apparatus as described in claim 45, comprising means for generating
color program data signals for controlling said controllable transfer
function circuits and program means for selectively inputting color
program data signals to said transfer function circuits.
48. Apparatus for area selective color conversion of a black and white
video signal, comprising:
a. a plurality of area signal generating means, each having an area signal
generator for generating an area signal corresponding to a respective area
of said video signal;
b. means for modifying said video signal to obtain a plurality of color
converted area modified signals, said modifying means having a plurality
of circuit paths, each path having function circuit means with a
respective selected transfer function for providing color conversion and
area modifying circuit means for receiving a respective one of said area
signals and providing modification of a respective selected area of said
video signal; and
c. summing means for summing said plurality of color converted area
modified signals.
49. The apparatus as described in claim 48, comprising function means for
deriving a signal from said video signal which is modified only as a
function of grey level, and combining means for combining said grey level
modified signal and said color converted area modified signals to provide
a primary signal.
50. The apparatus as described in claim 49, comprising a plurality of such
apparatus combinations, each respectively color converting said video
signal to provide a plurality of respective primary signals.
51. The apparatus as described in claim 48, wherein said area signal
generators generate area signals corresponding to soft edged areas.
52. A method for color converting a video signal which defines a changing
image, comprising:
a. monitoring said changing image while continuously color converting said
video signal according to a first function;
b. selecting for additional color conversion a first area of said changing
image;
c. selecting a larger area enveloping said first selected area;
d. color converting said video signal within said larger area according to
a different function, whereby said larger area receives additional color
conversion; and
e. selecting succeeding larger areas of said changing image which track
said first area as it moves, and additionally color converting said video
signal within said succeeding larger areas according to said different
function while also continuously color converting all of said video signal
according to said first function.
53. The method as described in claim 52, comprising selecting a plurality
of said first areas of additional color conversion, selecting a plurality
of respective said larger areas, and additionally color converting in
accordance with respective different conversion functions within said
larger areas.
54. The method as described in claim 52, wherein said selected area moves
in succeeding time portions, and said larger area is selected to
continuously envelope said selected area, and additionally color
converting said video signal according to said different function within
said larger area for said succeeding time portions.
55. The method as described in claim 52, wherein said color converting is
performed only on grey levels found within said video signal is initially
a black and white television signal, and said selected first area.
56. The method as described in claim 52, wherein said additionally color
converting corresponds to a selected different function, and changing said
different function during succeeding respective time portions of said
video signal.
57. The method as described in claim 56, wherein said changing is performed
between frames of said video signal.
58. Apparatus for color conversion of a video signal defining a moving
image, comprising:
a. input means for providing color program data signals time coordinated
with said video signal;
b. area signal means for providing at least one area video signal synced
with said initial video signal; and
c. circuit means for transforming said initial video signal by color
converting certain selected portions of said video signal which produce
selected respective areas of the total image produced by said video
signal, said circuit means including means for varying at least one of
said portions with time to track a predetermined one of said areas as it
moves, and means for carrying out said color converting under control of
said color program data signals; and
d. said circuit means comprising a plurality of paths, and said input means
having means for inputting a color program data signal to each of said
paths. |
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Claims |
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Description |
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BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to video color synthesizers and, more particularly,
to apparatus and techniques for transforming black and white video signals
to corresponding color signals, the transformed color signals containing
operator-controlled localized area color components which supplement the
overall color transformation of the video signal.
2. Description of the Prior Art
Video coloring apparatus and techniques, whereby black and white video
signals are transformed into color video signals, have been available for
some time. However, such prior art devices and techniques are based
predominantly, if not solely, upon techniques for transformation of grey
levels of the black and white signal into corresponding color signals. By
this technique, the incoming black and white video signal is effectively
digitized, with amplitudes which fall within a predetermined number of
discrete levels on the white to black scale being assigned corresponding
colors. However, this technique of color transformation, or color
conversion, carries the basic deficiency that the signal which is being
processed simply does not carry information corresponding to the color
components. In making a direct transformation from black and white to
color, as is done in the prior art, no new information is in fact added to
the color converted signal. Thus, all signals within a given grey level
range are transformed into the same corresponding color, whereas in fact
such grey levels may originally have been produced from distinctly
different colors having the same shades of brightness. For this reason,
unless and until additional information is put into the composite signal
it remains virtually impossible to perfect a straight color conversion
from black and white to color. Typical of the product which results from
prior art color converting techniques is the color picture where a certain
portion of the overall picture is well optimized, but another portion or
another feature stands out as being poorly converted. For example, in an
outdoor scene, bright portions of the frame may have a very excellent
color, while shady portions have a poor color. Likewise, it frequently
occurs that the background of a frame may have very excellent color,
whereas the face of an individual may be clearly untrue in its coloring.
The problem is acute, inasmuch as if any one sensitive portion of the
frame is poorly color converted, the viewer senses this immediately and
records displeasure with the entire scene. Color viewing is very
subjective, and generally the viewer is sensitive to the coloring of
certain features in an area or areas of the overall picture, to the
relative exclusion of others. If the coloring of such color sensitive
areas can be fine tuned without affecting the remaining portions, a highly
acceptable final picture is achieved.
There currently exists a very strong demand to obtain a satisfactory
technique for color converting black and white TV recordings and films.
There exist large libraries and quantities of film and TV recordings in
their original black and white state. If such films, which can be
converted to black and white video signals by conventional means, and
other video recordings, were available in satisfactory color, their value
would increase manyfold. However, prior attempts to provide such color
conversion have simply not been commercially acceptable, either because
the end product was not artistically acceptable or because the operation
was too expensive. This is evidenced by the fact that large numbers of
prior films and recordings which were made in black and white simply are
not utilized by the TV networks which show virtually no programs which are
not in color.
SUMMARY OF THE INVENTION
It is an object of this invention to provide apparatus for improved and
inexpensive color conversion of black and white video signals.
It is another object of this invention to provide improved color conversion
apparatus whereby an operator may easily and efficiently provide artistic
input to the color conversion procedure.
It is another object of this invention to provide a method of color
conversion which is easily performed by an operator of ordinary skill in
the art of color animation.
It is another object of this invention to provide apparatus which may be
manually and/or automatically controlled to provide improved color
conversion of black and white video signals, the control including
inputting selected color information which may be variable for different
frames and for different areas of any given frame.
It is another object of this invention to provide improved means and an
improved method for color conversion of black and white video signals, and
to provide for animated area control of the color conversion.
It is another object of this invention to provide a low cost and
commercially feasible technique of color conversion, which technique
provides a substantial improvement over prior art grey level to color
transforming techniques.
It is another object of this invention to provide a relatively low cost
system, utilizing conventional components, which enables an operator or
ordinary skill in animation to animate desired colors to coordinate with
selected moving images of the video signal.
It is a still further object of this invention to provide color conversion
apparatus for transforming black and white video signals to color video
signals, and incorporating means for soft edged area modification of the
color composition of the video signal.
It is a still further object of this invention to provide a device and
method for producing a color converted video signal from an original black
and white signal, which color converted signal may contain as a component
thereof the original black and white signal as the luminance signal.
It is still further object of the invention to provide a system for
generating color converted video signals, which system may be used in
combination with conventional film to video and video to film apparatus.
It is a still further object of the invention to provide a system for real
time area modified color converting of video signals.
In accordance with the above objectives, there is provided a color
converting system which receives a black and white video signal as a first
input and is adapted to enable an operator to produce therefrom a color
converted composite signal containing color components, adapted for color
TV. The system generates, independently of the black and white video
signal, one or more area signals for modifying the video signal
corresponding to preselected areas of the overall picture. The black and
white signal is first modified by a matrix of function generators under
operator control to provide a plurality of color converted signals, which
signals are further modified under operator control by the area signals,
to provide the composite color signal. In carrying out the process of this
invention, the operator makes choices of the function modifications
applied to the black and white signal, as well as the area modifications
and animation of the area modification signals, thereby providing the
operator's own artistic input to the composite color video signal. It is
the additional information and the ease and speed with which it is
logically introduced into the signal by the area signals, as well as the
artistic input of the operator in selecting the area modifications, which
provides the primary advantages of the system of this invention over the
prior art. The system produces a color video signal which may contain the
original unmodified luminance signal and thus is fully compatible for
black and white as well as color modification.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a block diagram illustrating the main logic portion of the
apparatus of this invention, whereby additional color function and area
signal inputs are provided to convert the black and white video signal.
FIG. 2 is another block diagram showing different features of the function
generator portion of the apparatus of this invention and its relation to
the overall system.
FIG. 3A is a more detailed schematic representation of the function
generator logic of the apparatus of this invention.
FIG. 3B is a schematic representation of the color program control inputs
to the function generator logic circuitry of this invention.
FIG. 4A is a schematic representation of a first means for generating an
area signal for use in the apparatus and method of this invention.
FIG. 4B is a second schematic representation of a second means for
generating an area signal for use in the system and method of this
invention.
FIG. 4C is a third schematic representation of a third means for generating
an area signal for use in the apparatus and method of this invention.
FIG. 5 shows 4 function graphs which illustrate area modification and color
conversion transfer functions as used in the apparatus and method of this
invention.
FIG. 6 is a block diagram showing an arrangement for editing and storing a
color program for color conversion of a black and white video signal in
accordance with the process of this invention.
FIG. 7A is a simplified block diagram of a 2 path system for generating an
area modified color converted video signal.
FIG. 7B is a simplified block diagram of a 1 path system which is the
function equivalent of the 2 path system of FIG. 7A.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
Referring now to FIG. 1, there is shown a first block diagram which
illustrates the primary components of the system of this invention. The
black and white video signal is inputted to an amplifier 40 of
conventional design, which may contain an amplitude and black level
correction portion. At the output of amplifier 40, the amplified black and
white signal may optionally be passed through a signal correcting circuit
42. Signal correcting circuit 42 is a conventional circuit containing
standard function generator circuitry for providing an initial overall
transformation of the black and white signal. As stated, this circuit is
optional, and the reason for including the circuit is discussed
hereinbelow at the portion of the specification where the overall system
operation is reviewed. The signal, whether or not processed by circuit 42,
is then connected to a plurality of function generator circuits 50-52,
60-62, and 70-72 as shown. These function generator circuits, which are
described in more detail in connection with FIGS. 2, 3A and 3B, provide
for alteration of the input signal by a predetermined function, as is
conventional in the art. It is to be noted that these function circuits
are illustrated as being in 3 groups, which groups correspond to the L, or
luminance path, the R-Y, or Red path and the B-Y, or Blue path. Although 3
generator circuits are shown for each of these paths, it is noted that in
the system of this invention each path may contain any number of such
function subpaths, the number being anywhere between 0 and whatever the
desired upper limit might be chosen to be. Each of these function circuits
provides a straight line type modification of the incoming signal, as is
well known in the art. Each such circuit may be a conventional shelf item,
or these circuits may be combined in a matrix as disclosed more fully in
connection with FIG. 3A.
Located between the inputs to the function circuits 50-52 of the first
path, and the inputs to the function circuits of the second and third
paths, is a second overall function generator circuit 44. As with circuit
42, this function generator is optional. As is evident, the modification
of the signal which is inputted to circuit 44 is applied to both of the
color paths, but not to the black and white path. It is seen that this
circuit actually has the effect of shifting the breakpoints on the input
axis of the R-Y and B-Y functions and provides a rough, or gross color
conversion to the two color paths, which conversion is not applied to the
luminance path.
Examining the function generator group 50-52 of the luminance path, it is
seen that generator 50, which provides a function f.sub.L0, i.e., f.sub.L0
is its transfer function, produces an output which is directly connected
to a summing amplifier 56, the output of which provides the overall
luminance signal designated "L". The outputs of function generator
circuits 51 and 52, which introduce separate functions f.sub.L1 and
f.sub.L2, are inputted to multipliers 53 and 54 respectively, the outputs
of which are also connected to the summing amplifier. Multiplier circuits
53 and 54 take respective second inputs from area generator blocks 81 and
82. The area generators 81 and 82 may be any source, external to the
source of the black and white signal, which provides an off-on type video
signal corresponding to a predetermined area within the total area of the
video frame or picture. Thus, by way of example, if area 1 was desired to
be the upper left hand quadrant of the frame, area 1 signal generator 81
would produce a signal which, as a first simplification, would be a black
and white video signal which would carry a level 1 corresponding to all
portions of each line of the frame covering the upper left hand quadrant,
and a level 0 corresponding to all other areas of the frame. In addition,
as will be discussed in more detail in connection with FIGS. 4A-4C, the
area signal is preferably "soft edged", meaning that the transition at the
area boundaries from 1 to 0 or from 0 to 1 is gradual, or continuous over
a predetermined range, rather than being discrete or discontinuous.
As is illustrated in FIG. 1, there may be any number of area signal
sources, depending upon the number desired for the system application. The
separate area signals are shown as being outputted onto lines 201 and 202,
which connect respectively to multipliers 53 and 54. Since each multiplier
is multiplying the function signal inputted thereto by a value between 0
and 1, it is seen that at the output of each multiplier is a signal which
has been twice multiplied, namely first in accordance with the function in
circuit 51 or 52, and second in accordance with the area signal. Thus, the
output of multiplier 53 provides a signal component, which is added to the
overall luminance signal in summing amplifier 56, which is non-zero only
within the predetermined area 1. Likewise, the output from multiplier
circuit 54 is summed into the composite L signal, which summed component
is non-zero only within area 2. It is thus seen that the composite L
signal contains separate area modification components, such that within
the predetermined separate areas the color component is modified in
accordance with the chosen function, e.g., f.sub.L1 or f.sub.L2. Note also
that the different area signals may overlap if desired, or there may be no
area modification whatsoever.
The operation of the Red and Blue paths, which produce signals outputted
from summing amplifiers 66 and 76 respectively, is the same as that
explained above for the luminance path. Each signal may be modified by one
or more area signals. Since each area signal is connected to a multiplier
in each path, and each path has at least one function circuit the output
of which is not modified by an area signal, it is seen that maximum
flexibility is provided to the system operator in choosing the manner of
deriving the overall composite signal. In the simplest case, as where no
area modification is required, no area signals are generated. In such a
case, if plural function components such as f.sub.R0, f.sub.R1, f.sub.R2,
etc. are needed, the corresponding area signals are clamped to 1.
Alternately, the multiplier circuits may be adjustable to provide a fixed
multiplication of any value between +1 and -1, as by adjustment of a pot.
Usually, however, where no area signal is employed, the function
multiplier level is introduced within the function circuit, as explained
below in connection with FIG. 3. In many applications the black and white
signal will be connected straight through to summing amplifier 56 in an
unmodified form, i.e., f.sub.L0 has a simple transfer function (L=aV where
a=1), meaning that the signal is unmodified.
Referring now to FIG. 2, there is shown a somewhat expanded version of the
portions of the system by which function modifications are made in
generation of the Luminance, Red and Blue signals. The black and white
video signal, after being amplified in amplifier 40, is connected to
breakpoint bias circuit 89. This circuit contains conventional circuit
components for providing breakpoint DC bias inputs to limiter amplifiers
91-95, which in turn may be conventional items which limit the output at a
predetermined value, as is well known in the art. By biasing the inputs
with the breakpoint bias circuitry 89, the linear range of each of the
amplifiers 91-95 is predetermined. The outputs of amplifiers 91-95, being
amplitude segments 1-5, designated AS1-AS5, are inputted to function
select circuitry 96. This circuitry chooses, corresponding to each of the
function generator blocks 50-52, 60-62, and 70-72 shown in FIG. 1, the
desired amplitude segments which are combined to provide the respective
functions. Block 96 also comprises the multipliers 53, 54, 63, 64, 73 and
74, and with the inputs from the spot, or area video blocks 81, 82 and the
input from program control source 97, provides the respective component
signals which are inputted to summing amplifiers 56, 66 and 76 for
generation of the Luminance, Red and Blue signals. The output from program
control circuit 97, which is shown as being communicated on line 197, goes
to each of the function generator circuits as additional input by which
the operator controls selection of the various amplitude segment signals,
as is explained further in connection with FIGS. 3A and 3B.
The system as illustrated in FIG. 2 contains a conventional Genlock type
sync generator 79, which receives the initial black and white video
signal. The sync generator output is connected through to the spot video
sources 81, 82, test generator 186, and the standard color TV encoder 78
which receives the L, R-Y and B-Y signals and combines them to provide the
composite color video output signal. It is understood that the matrix of
logic circuitry within dashed block 99 may be arranged to produce standard
Red, Green and Blue signals, or any other desired combination. The system
is unlimited in its ability to handle high resolution video signals or any
plural signal format as desired for any end application such as TV, films,
etc. Test generator 186 provides a test output which may be used by the
operator as an aid in determining the different colors which are produced
by different function generator settings. A program storage device 98 is
also provided, in connection with program control 97, for providing
frequently used color information program signals.
Referring now to FIG. 3A, the amplitude segment inputs, which are
illustrated in the upper left hand portion of the figure, are inputted to
logic circuit blocks 101, 102 and 103 respectively, which are coupled to
multipliers 53, 54 and 63. Each of logic circuit blocks 101-103 contains,
in this illustration, five logic circuits for either passing the amplitude
segment (+1), blocking it (0) or inverting it (-1). These logic functions
are conventional circuitry, and indeed circuits 101-103 are available
commercially as conventional integrated circuits. The output of each of
the +1/0/-1 logic circuits is inputted to the respective multiplier
circuit 53, 54, 63, 64, 73 or 74, the outputs of which are summed in the
summing amplifiers. Thus, focusing on the Luminance channel, the f.sub.L1
function, as shown being generated in block 51 of FIG. 1, is derived by
summing the outputs from logic circuit block 101. These outputs constitute
operator selected amplitude segments, thus providing a 5 segment function
generator. The respective outputs are summed at a summing point at the
input to multiplier 53, which may suitably comprise a standard operational
amplifier. It is thus seen that by making one of the 3 logic selections
for each of the 5 logic components of logic circuit 101, the operator is
able to select a specific one of a large number of possible functions for
modification of the signal. It is to be understood that, while a 5 segment
function generator is illustrated, any number of segments may be utilized,
in accordance with design considerations. In practice, it has been found
that the amplitude segment components of a function will not necessarily
be equally spaced on the input axis. However, the exact manner of
generating each function is a matter of choice, and is not limiting
insomuch as the scope of this invention is concerned.
Still referring to FIG. 3A, inputs 197 are shown going into each of the
logic circuit portions 101, 102 and 103. These inputs, there being 5 for
each of the logic circuit blocks of each of the 3 paths, carry signals for
making the logic selection of +1, 0 or -1. These logic signals, as
generated in program control block 97, are the means by which the operator
actually makes the selections of the precise functions. As is well
understood, the logic circuits may be replaced with equivalent devices,
such as continuously adjustable pots giving logic functions that multiply
by a constant within a continuous range of +1 to -1 when fed by the signal
and its inversion at its ends. In that case, the functions are set
manually by the operator. For more automatic control, the signals on lines
197 may be digital signals inputted from any desired source, such as
magnetic tape, etc., which control a four quadrant multiplier. There is,
as is understood, no limitation in the manner of generating the program
control signals.
As shown in FIG. 3B, the output of program control circuit 97 comprises 5
leads for each of the function logic blocks such as 101-103. If each of
the 3 main paths contains N function paths, and the logic circuit block
for each subpath contains X of the +1/0/-1 logic control circuits, then a
total of 3 NX control signal paths emanate from program control block 97.
Program control block 97 may suitably contain a keyboard for entry of
logic signals, switches, or any other conventional means by which the
operator can communicate with it. Program control 97 may be adapted to
receive a signal from the sync generator 79, not shown, for use in
automatically inserting the color program data in combination with program
storage device 98.
Summarizing at this point, each path produces a combined signal as follows:
L = f.sub.L0 (V) + A.sub.L1 f.sub.L1 (V) + . . . A.sub.LN f.sub.LN (V)
r-y = f.sub.R0 (V) + A.sub.R1 f.sub.R1 (V) + . . . A.sub.RN f.sub.RN (V)
b-y = f.sub.B0 (V) + A.sub.B1 f.sub.B1 (V) + . . . A.sub.BN f.sub.BN (V)
where V is the inputted video signal and the A functions are area
modification functions.
The functions may include positive or negative values out for positive
values of V in. Thus, adding the modifying functions can, if desired,
cancel the output of the other functions.
FIGS. 1-3 illustrate a system employing a plurality of subpaths for making
up each function and area-modified primary signal, which system permits
real time modification of a video signal. It is to be noted that other
equivalent techniques may be used. For example, any of the signals may be
generated with one path. Thus, in generating the L signal, the data
corresponding to f.sub.F0, f.sub.L1, . . . f.sub.LN, plus data
representing the A.sub.L1, A.sub.L2, . . . A.sub.LN functions may all be
inputted to a hard-wired or programmed computer which calculates the L
signal according to the above formula. It is not necessary that the video
signal be altered by separate transfer functions in separate circuits to
produce separate signals that are then summed. Instead, the different
color converting transfer functions and area transfer functions may be
logically combined to directly modify the video signal so as to generate
the desired color converted area modified resultant signal. Likewise, it
is to be understood that the time sequence of performing the functions
called for is a matter of choice. Thus, the video signal may first be
modified by the area signal and then be modified in accordance with the
transfer functions and vice versa, or both modifications can be carried
out together. In summary, although the embodiment of FIGS. 1-3 is
presently preferred from a hardware point of view, as well as for ease of
operation, the system embraces equivalent analog and digital circuitry and
accompanying input/output equipment, for performing the same essential
steps of color conversion and area modification.
By way of example of the foregoing, FIGS. 7A and 7B illustrate dual path
and single path variations. FIG. 7A illustrates a portion of FIG. 1,
showing two subpaths which are combined to modify the video signal in
accordance with the equation E.sub.0 = f.sub.0 (V) + Af.sub.1 (V). Color
program data P.sub.0 is inputted to block 50 to establish the transfer
function f.sub.0, while data P.sub.1 is inputted to block 51 to establish
the transfer function f.sub.1. In FIG. 7B, there is illustrated a single
circuit block 250 which modifies the input in accordance with transfer
function f.sub.c. However, f.sub.c in turn is established by program data
P.sub.c from circuit block 251, and P.sub.c in turn is obtained by
combining the P.sub.1 and P.sub.2 data inputs in accordance with the
inputted area signal A. Where A varies from 0 to 1, P.sub.c is modified in
accordance with the illustrated formula P.sub.c = AP.sub.1 + (1-A)P.sub.0,
such that function f.sub.c effectively varies from f.sub. 0 to f.sub.0 +
f.sub.1 so as to produce the same E.sub.0 as in the arrangement of FIG.
7A. Note that in the arrangement of FIG. 7B, the combination circuit may
operate upon the program parameters in any desired manner to modify the
program data. Additionally, the arrangement of FIG. 7 may be further
modified so that all function modification takes place in one box, e.g., a
digital computer, which receives the video input, the area signal input,
and the color parameter input, and produces the color conv | | |
