JPH08336072A - Wipe pattern generating device - Google Patents

Abstract

PURPOSE: To reduce the circuit scale and the cost by generating a specific wipe pattern inside a graphic ROM and using a data interpolation device to a less part than accessed part in the graphic ROM. CONSTITUTION: An address generator 11 generates continuously an orthogonal coordinate of a wipe pattern based on a picture element reference CLK, a horizontal reference pulse HD and a vertical reference pulse VD primarily and outputs the generated address to a graphic ROM 12. The graphic ROM 12 stores the wipe pattern as data and outputs graphic data corresponding to an address signal outputted from an address generator 11 to a data interpolation device 13. The data interpolation device 13 interpolates areas of the graphic ROM 12 less than the access time when the graphic data are used for a graphic on a television receiver to smooth edges and the resulting data are outputted to a comparator 14. The comparator 14 provides a wipe pattern with a different size by varying a threshold level outputted from a controller 15.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a special effect technique for an image, and more particularly to a wipe pattern generator for generating a graphic such as a heart shape which can be polar coordinates.

[0002]

2. Description of the Related Art Conventionally, a graphic generator capable of becoming polar coordinates is provided with a coordinate conversion circuit for converting rectangular coordinates into polar coordinates, an arithmetic circuit, and a graphic ROM, and a wipe pattern is realized by a parallel combination of them. There is. FIG. 6 shows the configuration of a conventional wipe pattern generator, which includes an address generator 1 for generating Cartesian coordinates, a coordinate conversion circuit 2 for converting Cartesian coordinates into polar coordinates, and arithmetic circuits 3, 4 for performing arithmetic operations.
And a graphic ROM 5 storing graphic data and a graphic R
It is provided with a comparator 6 for comparing the outputs of the OM 5 and the arithmetic circuit 4 to obtain an output figure.

[0003]

However, the above-mentioned conventional wipe pattern generator requires a plurality of arithmetic circuits according to the wipe pattern, and the more complicated the figure is, the more the arithmetic circuits need to be reconstructed. There is a problem in that the cost increases as the circuit scale increases.

An object of the present invention is to solve such conventional problems, and an object thereof is to provide a wipe pattern generator capable of reducing the circuit scale and the cost.

[0005]

In order to achieve the above object, the present invention comprises an address generator for generating Cartesian coordinates, and
A graphic ROM storing graphic data, a data interpolator for smoothing the graphic, and a comparator for varying the size of the graphic by varying a predetermined threshold value are provided.

[0006]

Therefore, according to the present invention, the wipe pattern is generated by providing the cubic ROM with the cubic function data based on the operation table consisting of the two terms of z = f (x, y). The data interpolator is used to interpolate the portion of the graphic ROM that is less than the access time,
By changing the above, a predetermined wipe pattern can be generated irrespective of the polar coordinate figure, and the circuit scale and cost can be reduced.

[0007]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows the configuration of a wipe pattern generator according to an embodiment of the present invention. In FIG. 1, 11
Is an address generator that generates rectangular coordinates, 12 is a figure ROM that stores figure data, 13 is a data interpolator that smooths the figure, and 14 is the size of the figure by varying a predetermined threshold value. , 15 is a controller for generating a predetermined threshold value.

Next, the operation of the above embodiment will be described.
The address generator 11 primarily and continuously generates orthogonal coordinates of the wipe pattern based on the pixel reference CLK, the horizontal reference pulse HD, and the vertical reference pulse VD, and outputs the generated address to the graphic ROM 12. The graphic ROM 12 stores the wipe pattern as data and outputs graphic data corresponding to the address signal output from the address generator 11 to the data interpolator 13. Data interpolator 13
When the graphic data output from the graphic ROM 12 is converted to a graphic on a television, the edge of the graphic ROM 12 is smoothed by interpolating a portion less than the access time, and the graphic data is output to the comparator 14. The comparator 14 continuously outputs the wipe patterns having different sizes by varying the threshold value output from the controller 15.

Next, a method of creating the graphic ROM 12 in this embodiment will be described. FIG. 2 shows a method of creating a graphic ROM in this embodiment. In FIG. 2, since the heart-shaped wipe pattern data is considered to be bilaterally symmetric, if the address signals are bilaterally symmetric, the pattern RO
As the data of M, one of the left and right data may be stored. The equation of the circle at the point (x ₁ , y ₁ ) moved by 30 degrees from the (x ₀ , y ₀ ) in the Cartesian coordinates with respect to the x axis by the radius r is (x−x ₁ ) ² + (y−y ₁ ) ² = r ² ... (1)

Therefore, the maximum address is 256 in the x direction,
If we derive the positive part of Cartesian coordinate y as the y direction 256, that is, the upper half of the heart shape from the equation, from the Pythagorean theorem, x ₁ = √3 / 2r, y ₁ = 128 + r / 2, and the height is When z is represented by r, assuming that the maximum is 256, r = (256-z) / √3 (2) Substituting x ₁ and y ₁ into the equation (1) gives (x−√3r / 2) ² + (y−128−r / 2) ² = r ² (3), so r = ( x ² + y ² -256y + 128) ² / (√3x + y-128) (4).

Substituting equation (4) into equation (2) to make it a function of z = f (x, y),

[Equation 1] Allows the upper half of the heart shape to be derived by two Cartesian coordinate variables x and y.

For the lower half of the heart shape, that is, the portion where y is negative, the intersection (x ₂ , y ₂ ) of the circle from (x ₁ , y ₁ )
Along by 4r radius (x _4, y ₄₎ of the circle in equation ^{_{(x-x 4) 2 +}} (y-y 4) 2 = a ^{(4r) 2 ··· (6)} , 2 quadratic equation Then, the solution of r = [-(2√3x-2y + 512) + {(2√3-2y + 512) ² +36 (x ² + y ² -256y + 16284)} ^1/2 ] /-18 (7) From z = 256-√3r,

[Equation 2] Can be guided by.

FIG. 3 shows a formula for creating heart-shaped data. Using the equations (5) and (8) above, two variables x and y are obtained from a calculation table in a computer or the like, and the result is converted from DECIMIN to HEX to create data to be stored in the graphic ROM 12. You can

In this embodiment, the heart shape is described as an example, but the spiral wipe pattern data can be created by the arctangent function of each of x and y. A new pattern can be realized only by changing the graphic ROM without construction.

Next, the data interpolator 13 in this embodiment.
Will be described. FIG. 4 shows the configuration of the horizontal data interpolator in the data interpolator 13. In FIG. 4, 21 is a D flip-flop, 22 and 23 are adders, and 24, 25 and 26 are selectors. The D flip-flop 21 latches data at the second bit (H _{1 −} ) from the bottom of the address of the graphic ROM 12. Since the figure ROM data is decided 150 to 250 ns after the address is decided, the adders 22 and 23 delay so that three data are interpolated between about 4 times the pixel reference CLK 70 ns, that is, the figure ROM data. The averaged data and the original data. By adding two data and then bit-shifting, 1: 1, 3/4: 1/4,
It is possible to obtain data with a ratio of 1/2 to 1/2 and 1/4 to 3/4.
By arranging in the order of OM addresses, horizontal linear interpolation can be realized.

FIG. 5 shows the configuration of the vertical data interpolator in the data interpolator 13. In FIG.
Reference numeral 31 is a 1H delay device, 32 is an adder, and 33 is a selector. The 1H delay device 31 is a means for obtaining data delayed by one line, and in order to interpolate the data from the graphic ROM 12 between vertical frames, the lower 2nd bit (V ₁ ) of the V address sequentially By switching the data averaged by the adder 32 between two lines by the selector 33, it is possible to perform vertical interpolation at a ratio of 1/2 of each of the two lines.

When the graphic ROM 12 is converted to a graphic on a television, the horizontal and vertical data interpolators shown in FIGS. 4 and 5 are connected in series to interpolate a portion of the graphic ROM 12 which is shorter than the access time. This makes it possible to smooth the edge portion of the figure.

[0018]

As is apparent from the above embodiment, the present invention realizes the coordinate conversion circuit and the arithmetic circuit by the ROM regardless of the polar coordinate figure, and does not reconstruct a new arithmetic circuit. In addition, a new pattern can be realized only by changing the ROM, and the circuit scale can be reduced as compared with the conventional one, so that the cost can be reduced.

[Brief description of drawings]

FIG. 1 is a block diagram of a wipe pattern generator according to an embodiment of the present invention.

FIG. 2 is a ROM calculation diagram of a figure for a heart-shaped wipe pattern in one embodiment of the present invention.

FIG. 3 is a ROM stand-up diagram of a figure for a heart-shaped wipe pattern in one embodiment of the present invention.

FIG. 4 is a block diagram of a horizontal data interpolator according to an embodiment of the present invention.

FIG. 5 is a block diagram of a vertical direction data interpolator according to an embodiment of the present invention.

FIG. 6 is a block diagram of a wipe pattern generator in a conventional example.

[Explanation of symbols]

 11 address generator 12 graphic ROM 13 data interpolator 14 comparator 15 controller 21 D flip-flop 22, 23 adder 24, 25, 26 selector 31 1H delay device 32 adder 33 selector

Claims (4)

[Claims] 1. An address generator for generating Cartesian coordinates,
A graphic ROM for storing the graphic data and outputting the graphic data corresponding to the address signal from the address generator;
A data interpolator for smoothly interpolating the graphic data output from the graphic ROM so as to be suitable for display, and a comparison for varying the size of the graphic from the data interpolator by changing a predetermined threshold value. Pattern generating device with a container. 2. The graphic ROM formulates a graphic in which the solution of the equation is a pole by a cubic function of z = f (x, y), and converts the data resulting from the solution of the equation into DECIMAL to HEX. The wipe pattern generator according to claim 1, wherein the wipe pattern generator stores the wipe pattern. 3. The wipe pattern generator according to claim 1, wherein the data interpolator smoothes an edge portion by interpolating a portion less than the access time of the graphic ROM. 4. The wipe pattern generator according to claim 3, wherein the data interpolator comprises a horizontal data interpolator and a vertical data interpolator connected in series.