JP2000324393A - Signal generator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To generate a solid function signal representing a rectangle whose corners are rounded or a wipe effect of the shape as above by means of functional process. SOLUTION: The signal generator generates a solid function that is used for a wipe generator that displays a rectangle whose corners are rounded on a screen and this rectangle is suitably used for image switching processing by a wipe. The solid function signal generator is provided with ramp function signal generators 30, 32 that respectively generate ramp functions X, Y. Absolute processing 34, 36 are applied to signal values of the ramp functions X, Y and offset processing 38, 40 are applied and also limit processing 42, 44 are applied. A polar coordinate conversion processing section 46 convert signals Px, Py receiving the processing above into a polar coordinate form (R2)1/2=(Px2+ Py2)1/2. In the case of generating a wipe effect, it is preferred to change magnitude of the offset as the image area by the wipe is extended.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a video wipe
It relates to a signal generator used for a generator. A video wipe generator, also called a wipe effect generator, is used in a vision mixer to perform an image switching process from an image of one video source to an image of another video source in a wipe manner. I have.

[0002]

2. Description of the Related Art A description will now be given with reference to FIGS.

FIG. 1 is a diagram for explaining a well-known simple wipe-type image switching process for switching between an image of a video source X and an image of a video source Y. As the image switching by the wipe method progresses on the screen as shown by the arrow W, the image portion of the video source X is replaced with the image portion of the video source Y (inversely, the video source Y). The image part of the source Y can be replaced with the image part of the video source X). The screen switching process by the wipe effect is performed by mixing the video signal of the video source X and the video signal of the video source Y in accordance with the following equation: KX + (1−K) Y. Is a keying signal. This keying signal K is derived from the “solid function signal”. This will be described below with reference to FIGS.

A solid function signal is an electrical signal representing a three-dimensional surface having a desired shape. The solid function signal is composed of at least one ramp function signal, and is usually composed of a combination of two or more ramp function signals. Each lamp function signal constituting the solid function signal may be subjected to a modification process in advance. The solid function signal may take the form of a signal defined in a polar coordinate system, in which case the solid function signal is a signal representing a curved surface.

FIG. 2A shows a known concrete example of the solid function signal 125. The solid function signal 125 shown in FIG. 2 is composed of only one ramp function signal. As shown in FIGS.
Set the level 142. This clip level 142
Defines a plane that extends over the entire field or frame, and this plane 142 will be referred to herein as the clip plane. This clip plane 1
42 will be described in more detail later with reference to FIG. The method of deriving the keying signal K from the solid function signal is well known, that is, as shown in FIG. 2B, a signal obtained by amplifying the solid function signal with a high gain is subjected to limit processing. I just need. As a result, the keying signal is obtained as a two-level signal having one of the levels “0” and “1”. This keying signal is
At the point where the solid function signal crosses the clip plane 142, it transitions from one level to the other. As shown in FIG. 2C, by giving an offset to the solid function signal, the position where the solid function signal crosses the solid function signal can be changed, so that a wipe effect can be generated.

FIG. 3 is a block circuit diagram of a wipe generator of a vision mixer. This wipe generator is a solid function signal generator,
It includes a clip element, a gain element, a limiter, and a mixer. The mixer mixes the video source X and the video source Y in accordance with the keying signal K. The solid function signal generator generates a solid function signal, and the generated solid function signal is, for example, a ramp function signal as shown in FIG. 2A. The clipping element causes the ramp function represented by the ramp function signal to be offset by adding an offset to the ramp function signal.
The position of the intersection line intersecting with 42 is changed as shown in FIGS. The gain is applied to the gain function signal to the ramp function signal to which the offset is applied in this manner, and the signal obtained thereby is subjected to a limit process in a limiter, so that the keying signal K
Is obtained. As shown in FIG. 2B, by changing the magnitude of the applied gain, it is possible to change the gradient of the portion of the keying signal K that transitions between the upper limit and the lower limit.

[0007] The mixer mixes the video source X and the video source Y according to the equation KX + (1-K) Y. According to this mixing method, when K = 1, the output signal is the video source X itself,
When K = 0, the output signal is video source Y
It becomes itself. When the gain given to the solid function signal is “1” and the offset amount of the clip plane is “0”, the solid function signal and the keying signal are the same signal.

In the specific examples shown in FIGS. 1 and 2, for simplicity of explanation, the generated solid function signal is constituted by only one ramp function signal.
Moreover, the solid function, that is, the ramp function, is a function of only the pixel position h on the scanning line, and generates a simple wipe effect. However, h on the screen
It is also possible to generate a solid function signal that varies as a function of both the coordinates (pixel position) and the v-coordinate (scan line number), thereby allowing a more complex wipe effect to be generated.

It is desired to generate a solid function signal that can display a rectangle with rounded corners on a screen. It is also desired to generate a wipe effect by a rectangle with rounded corners.

[0010]

As a method for generating such a solid function signal and such a wipe effect, a signal value necessary for generating the solid function signal is stored in a look-up table in advance. A method has been proposed so far. However, this method requires a large storage capacity and is inflexible.

It is an object of the present invention to generate a solid function signal representing a rectangle with rounded corners or a wipe effect of such a shape by a functional theory process.

[0012]

According to the present invention, there is provided a solid function signal generator, comprising: a first ramp function signal generator and a second ramp function signal generator. Wherein the first ramp function signal generator comprises a first
The signal value of the ramp function X is generated according to the formula: X = Ah + Bv + Cx, where h is the pixel count value in the scan line direction, v is the scan line count value, and A, B, and C is a coefficient each of which can take a positive or negative value, and the second ramp function signal generator has a slope direction of the first ramp function X
The signal value of the second ramp function Y orthogonal to the inclination direction of is generated according to the following equation: Y = Ah + Bv + Cy,
The signal values of the ramp function X and the second ramp function Y both pass a zero value, and the signal values representing the absolute values of the signal values of the first ramp function X and the second ramp function Y are Generating means for performing an offset process and a limit process on a signal value representing an absolute value of a signal value of the first ramp function X and the second ramp function Y, so that each of the ramp functions X and Y Has a 0-value area, and has a signal value representing the absolute value of the signal value of the first ramp function X and the signal value of the second ramp function Y, which has been subjected to offset processing and limit processing. A solid function signal generator comprising polar coordinate conversion processing means for generating a solid function signal by performing a polar coordinate conversion process.

[0013] Such a solid function signal generator comprises:
It is possible to generate a solid function signal representing a rectangle with rounded corners without using a look-up table.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in more detail with reference to the accompanying drawings in accordance with preferred embodiments. In order to supplement the description, the specification of the “lamp function signal generator” filed on the same day by the same applicant as this application is attached as Appendix A, and the entire contents thereof are incorporated. FIG. 4 shows a rectangle with rounded corners. Each of the four corners of this rectangle is formed by a quarter arc. Displaying this rectangle on the screen as a figure having a fixed shape is also one embodiment of the present invention. It is also one of the preferred embodiments of the present invention to generate a wipe effect of a rectangular shape with rounded corners. One of the wipe effects of such a shape
One specific example is to make the rectangle of this shape expand outward from the point O, as indicated by the arrow W. In that case, the lengths of the linear portions of the four sides of the rectangle can be increased.
The radius of curvature of one corner may be increased. Further, the rectangle need not be square, but can generally be either a square or a rectangle.

FIGS. 5 to 9 are diagrams showing signals used to generate a solid function signal that enables a rectangle having the shape shown in FIG. 4 to be displayed on a screen.

FIG. 5 shows a conical solid function. Here, for simplicity of explanation, X in FIG.
The Y plane corresponds to the frame of the video signal of the progressive scanning system, X is the scanning line direction (horizontal direction of the screen),
It is assumed that Y is the frame direction (vertical direction of the screen) orthogonal to the scanning line direction. The origin O is set at the center of the XY plane. A signal value of a ramp function signal is generated along each of all the active scanning lines of this frame, and a signal value of the generated ramp function is a signal value expressed in a two's complement form. It is also assumed that the dynamic range of the ramp function signal is from -M to + M. Therefore, the signal value of the ramp function signal passes through 0 at the center line extending vertically in the left and right centers of the frame. Such a ramp function is represented by X = Ah, where h is a count value of a pixel on a scan line (a value representing the number of pixels counted from the first pixel of the scan line), A is the slope of this ramp function.

A similar ramp function signal is also generated in the Y direction. The ramp function is represented by Y = Bv,
In this equation, v is the scan line count value (a value indicating the number of the scan line counting from the first scan line in the frame), and B is the slope of this ramp function.

The ramp function X thus generated,
FIG. 6 shows the signal value of the ramp function Y.

The conical solid function of FIG. 5 is represented by the signal value R generated according to the equation R ² = X ² + Y ² ,
By transforming this equation, R = (X ² + Y ² ) ^1/2 .

The signal values shown in FIG. 7 are signal values representing the absolute values of the signal values of the ramp function shown in FIG.

From the signals shown in FIGS. 6 and 7, a signal representing a conical function as shown in FIG. 5 is generated.
It should be noted that the ultimate goal is to generate a rectangle having four sides of a straight line and four rounded corners.

The conical function shown in FIG. 5 and the ramp function shown in FIGS. 6 and 7 both have X = 0 and Y = 0.
The value at the point represented by is 0. This point is hereinafter represented by (0, 0).

8 and 9, the signal values | X | and | Y | obtained by subjecting the signal values of the ramp functions X and Y to absolute value processing shown in FIG. 7 are further subjected to offset processing. By doing so, the signal values | X | and | Y | can both be 0 inside a certain rectangular area 20. When this offset processing is performed, the function which is conical as shown in FIG. 5 is deformed, and as shown in FIG. 9 by a line surrounding the outside of the rectangular area 20,
It is a function having a rectangular cross-sectional shape with rounded corners.
Outside the rectangular area 20, the signal values | X | and | Y | do not both become zero. In particular, the four regions 2 shown in FIG.
At 1, 22, 23, and 24, since X ² and Y ² both take non-zero values, the shape of the above function represented by the signal value generated according to the equation of R ² = X ² + Y ² Is
In these regions 21, 22, 23, and 24, the cross-sectional shape is a quarter-arc shape. Further, in the remaining four regions 25, 26, 27, and 28 shown in FIG. 9, one of the signal values X and Y becomes 0, so that a side formed of a straight line is generated.

Accordingly, as shown in FIG. 8, the corners are rounded by setting the height of the clip plane CP at a position higher than the zero level of the signal value of the ramp function subjected to the absolute value processing. A rectangle can be generated.

Therefore, as shown in FIG. 8, the magnitude of the offset given to the signal value of the ramp function subjected to the absolute value processing is fixed, and the clip plane CP is moved in the direction of W in FIG. Thus, a wipe effect as shown in FIG. 9 can be generated. When the wipe effect is generated in this manner, a rectangle obtained by rounding a corner that expands on the screen by the wipe effect has a constant linear portion of the four sides. Only the radius of curvature of one corner increases.

As another preferred embodiment of the present invention, when a rectangle with rounded corners is enlarged on a screen by a wipe effect, a straight line portion of four sides of the rectangle is formed. There are things that increase in length. To achieve this, the magnitude of the offset given to the signal value of the ramp function subjected to the absolute value processing shown in FIG. 8 is increased as the rectangle expands on the screen by the wipe effect. Then, the above-described rectangular area 20 is indicated by an arrow W in FIG.
What is necessary is just to make it expand as shown by 2.

FIG. 10 is a block circuit diagram of the wipe generator according to the embodiment of the present invention.

The wipe generator shown in FIG.
A ramp function signal generator 30 for generating a signal value of the ramp function X and a ramp function signal generator 32 for generating a signal value of the ramp function Y are included. These ramp function signal generators 30 and 32 may have the same configuration as the ramp function signal generator described in Appendix A, for example.

The ramp function signal generators 30, 32 generate, for example, ramp function signals as shown in FIG. Then, the absolute value processing (processing for obtaining the absolute value) is performed on each of the ramp function signals in the absolute value processing circuits 34 and 36, so that the absolute values of the signal values of the ramp function as shown in FIG. The signals | X | to | Y | representing the values are generated. Subsequently, the clipping circuits 38 and 40 perform offset processing (processing to add an offset) to the signal values of the ramp function that have been subjected to the absolute value processing. This is done as a subtraction. The signal values of the ramp function that have been subjected to the absolute value processing and the offset processing are then subjected to limit processing in the limiters 42 and 44, and as a result of this limit processing, as shown in FIG. Is set to 0. The signal values Px and Py of the ramp function that have been subjected to the absolute value processing, the offset processing, and the limit processing are supplied to the polar coordinate conversion processing unit 46. Since the configuration of the polar coordinate conversion processing unit 46 is a known general one, the description of the configuration is omitted. The polar coordinate conversion processing unit 46 executes a calculation process according to the formula (R ² ) ^1/2 = (Px ² + Py ² ) ^1/2 , whereby a function having a sectional shape as shown in FIG. 9 is obtained. Is obtained.

The signal value (R ² ) ^1/2 obtained in this way is
It is supplied to a keying signal generator 48, which has, for example, a configuration as shown in FIG.

To generate a wipe effect, a wipe control signal W is supplied from the wipe control unit 50 to the keying signal generator 48. The wipe control unit 50 further supplies a value representing the magnitude of the offset to be added to the signal value representing the absolute value of the ramp function to the clipping circuits 38 and 40. When the wipe control signal W is transmitted, the value representing the magnitude of the offset is changed according to the value of the wipe control signal W, so that the rectangle with rounded corners is enlarged on the screen by the wipe. When going, the lengths of the linear portions of the four sides of the rectangle can be changed.

In the above description, the inclination direction of the ramp function X is adjusted to the scanning line direction which is the horizontal direction of the screen, and the inclination direction of the ramp function Y is adjusted to the frame direction which is the vertical direction of the screen. However, it is necessary to make the inclination direction of the ramp function X and the inclination direction of the ramp function Y orthogonal,
It is not always necessary to match those inclination directions with the scanning line direction and the frame direction. By not matching the inclination directions of these ramp functions with the scanning line direction and the frame direction, a rectangular wipe area rotated with respect to the scanning line direction and the frame direction can be generated.

The wipe generator of FIG. 10 also includes components for generating a solid function having a curved surface having a shape different from that of the solid function described above. explain.

The selector 52 is controlled by the selection signal SEL, and outputs the ramp function signals of the ramp functions X and Y to the components 34, 36, 38, 40, and 4 described above.
The signals are supplied to the above-mentioned polar coordinate conversion processing unit 46 without any processing being applied to those signals, bypassing the subsystem 54 composed of the components 2 and 44.

The polar coordinate conversion processing section 46 generates a signal represented by the following equation by a known signal conversion method. (R ² ) ^1/2 = (X ² + Y ² ) ^1/2 , and θ = arctan (| Y | / | X |)

By using the signal θ generated in this way and changing the value of (R ² ) ^1/2 according to the angle θ, a solid function having a non-circular curved surface can be obtained. Can be generated. Signal modification processing for that is performed in the signal modification processing circuit 56. To generate the above-described rectangle with rounded corners, the selection signal SE
The signal modification processing circuit 56 may be disabled by L.

Although the specific example of the present invention described above is the case where the present invention is applied to a frame of a progressive scanning system, the present invention is also applicable to an interlaced field.

In the embodiment of the present invention described above, a rectangle is generated at the center of a frame or a field. However, a rectangle can be generated at any position of a frame or a field. The rectangle occurs because of the ramp function X in the frame or field.
And the point where the signal value of Y is 0. Therefore, by adding the offsets Cx and Cy to the ramp function signal values to be generated in the ramp function signal generators 30 and 32, it is possible to move the rectangular generation position.
In this case, if the inclination directions of the ramp functions X and Y are adjusted to the scanning line direction and the frame direction, the ramp functions X and Y are represented by X = Ah + CxY = Bv + Cy.

Further, the ramp X and Y functions are more generally expressed by the formulas X = Ah + Bv + C ′ x and Y = Ah + Bv + C ′ y as described in Appendix A. In order to carry out the invention, it is further required that the inclination directions of the ramp functions X and Y are orthogonal to each other, as described above.

[Brief description of the drawings]

FIG. 1 is a diagram showing a specific example of a wipe effect.

FIG. 2 is a diagram showing a solid function together with a keying signal.

FIG. 3 is a block circuit diagram of a wipe generator.

FIG. 4 is a diagram showing a specific example of a rectangle with rounded corners.

FIG. 5 is a diagram showing a conical solid function having a circular cross section.

FIG. 6 is a diagram showing a ramp function.

FIG. 7 is a diagram showing a ramp function subjected to absolute value processing;

FIG. 8 is a diagram showing a ramp function subjected to an absolute value process and an offset process;

FIG. 9 is a diagram showing a cross-sectional shape of a solid function generated according to the present invention.

FIG. 10 is a block circuit diagram of a wipe generator according to the present invention.

[Explanation of symbols]

20 ‥‥ rectangular area, 30, 32 ‥‥ ramp function signal generator, 34, 36 ‥‥ absolute value processing circuit, 38, 40
{Clip circuit, 42, 44} Limiter, 46}
Polar coordinate conversion processing unit, 48 ° keying signal generator, 50 ° wipe control unit

Claims (5)

[Claims] 1. A solid function signal generator comprising: a first ramp function signal generator and a second ramp function signal generator, wherein the first ramp function signal generator outputs a signal value of a first ramp function X; Ah + Bv + Cx, where h is the pixel count value in the scan line direction, v is the scan line count value, and A, B and C are coefficients that can each be positive or negative. Wherein the second ramp function signal generator generates a signal value of a second ramp function Y whose inclination direction is orthogonal to the inclination direction of the first ramp function X according to the following equation: Y = Ah + Bv + Cy. The signal values of the first ramp function X and the second ramp function Y both pass a zero value. And means for generating a signal value representing the absolute value of the signal value of the first ramp function X and the signal value of the second ramp function Y. The signal value of the first ramp function X and the signal value of the second ramp function Y Means for performing an offset process and a limit process on a signal value representing an absolute value of the first and second ramp functions X and Y so that each of the first and second ramp functions X and Y has a zero-value area. (2) polar coordinate conversion processing means for generating a solid function signal by performing a polar coordinate conversion process on a signal value obtained by performing an offset process and a limit process on a signal value representing an absolute value of a signal value of the ramp function Y; Features solid function signal generator. 2. The solid function signal generator according to claim 1, further comprising a keying signal generator for generating a keying signal based on the solid function. 3. The solid function signal generator according to claim 2, wherein said keying signal generator includes means for generating a wipe effect by applying an offset to said solid function signal. 4. The magnitude of the offset given to the signal value representing the absolute value of the signal value of the first ramp function X and the signal value of the second ramp function Y depends on the magnitude of the offset given to the solid function signal. 4. The solid function signal generator according to claim 3, wherein said signal is varied by changing said value. 5. Substantially the same as described in the specification with reference to FIG. 10 of the accompanying drawings, or substantially further modified according to FIG. 3 of the accompanying drawings. Identical solid function signal generator.