JP2712303B2 - Wipe pattern generator - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for generating a wipe pattern signal used for special video effects.

[Summary of the Invention]

The present invention relates to an apparatus for generating a wipe pattern signal using a memory in which data of a wipe pattern is stored, wherein the contour of the wipe pattern is represented by polar coordinates, and a predetermined distance is defined between the contour of the wipe pattern and the origin of the polar coordinates. By adding a numerical value or a modulation signal, the shape of the wipe pattern can be easily changed.

[Conventional technology]

For example, on a television screen, there is a screen conversion technique in which a different screen is displayed on a wipe pattern of various shapes such as a square and a circle.

FIG. 9 is a diagram showing an example of a wipe pattern generator for digitally performing such a conversion technique, and FIG. 10 is an explanatory diagram of the example of FIG.

In the figure, a horizontal drive signal HD and a vertical drive signal VD are supplied to respective sawtooth wave generating circuits (1) and (2). From the sawtooth wave generating circuits (1) and (2), sawtooth waves H and V are obtained and supplied to a coordinate conversion circuit (3). In the coordinate conversion circuit (3), for example, a position on a screen is displayed. Coordinate data (x,
y). Then, the coordinate data (x, y) is supplied to the graphic memory (4).

In the graphic memory (4), for example, as shown in FIG.
Data indicating a cone C whose cross section is a square wipe pattern W is stored. That is, the height h of the weight C with respect to the rectangular coordinates (x, y) in the bottom surface B of the cone C is stored as data. For example, the height h ₁ is stored against the bottom surface B coordinates (x _1, y _1). Data indicating the height h with respect to the coordinates (x, y) obtained by the graphic memory (4) is supplied to one input terminal of the comparison circuit (5). The other input terminal of the comparison circuit (5) is supplied with a fader level L indicating a cross section at which height of the weight C, that is, a size of the wipe pattern W to be used. And
In the comparison circuit (5), the height h at the coordinates (x, y) is compared with the fader level L. For example, if the height h is equal to or higher than the fader level L, "1"; A signal which becomes "0" is output from the comparison circuit (5) as a wipe pattern output signal.

In the case of the example of FIG. 9, for example, by gradually decreasing the value of the fader level L, the wipe pattern W is gradually increased as shown in FIG. it can.

[Problems to be solved by the invention]

Now, in the conventional wipe pattern generator, the data indicating the weight C whose cross section is the wipe pattern W is very large, and the capacity of the figure memory (4) for storing the data is very large. I will. For example, if one of the resolution of 2 ¹⁰ kinds to indicate the height of the weight in Fig. 12, the resolution of the base of the spindle is required are two ^11. Thus changing the aspect ratio of the graphics such, and 4 times the base as shown for example by the dotted line, the bottom will be that of the resolution of 2 ¹³ kinds. In this case, assuming that the coordinates (x, y) are (13 bits, 13 bits), the address of the figure memory is 2 ¹³ × ²¹³ and the height data is 10 bits. 2 ¹³ × 2 ¹³ × 10 ≒ 640 Mbits, which is not practical.

Further, in the conventional wipe pattern generator, the thirteenth
As shown in FIG. 14 and FIG. 14, the contour of the contour is wavy, that is, a wipe whose contour changes in the x direction or the y direction as indicated by a solid line based on the circular wipe pattern W1 indicated by the broken line. When a pattern is generated, a sine wave signal corresponding to the wavy contour may be added to the sawtooth wave H or V supplied to the coordinate conversion circuit (3).

However, as shown in FIG. 15, in the case of obtaining a wipe pattern (shown by a solid line) whose contour changes in a wavy shape in the radial direction with respect to the reference circular wipe pattern W1, the circuit configuration becomes complicated.

[Means for solving the problem]

According to the present invention, the first distance data of the first angle data indicating the outline of the wipe pattern in the polar coordinate system and the first distance data corresponding to the first angle data corresponds to the first angle data. The storage means (10) stored at the address, second angle data indicating the position of each pixel on the display screen in the polar coordinate system, and second distance data are generated, and the second angle data is stored in the storage means. A pixel position data generating means (18) to be supplied to the storage means as data indicating an address;
(9) for adding predetermined numerical data to the first distance data read from the storage means when the angle data is supplied, and the first distance data and the pixel after addition output from the addition means. A wipe pattern data generating means (12) for generating wipe pattern data based on the magnitude relation of the second distance data output from the position data generating means.

[Action]

In accordance with the output signal of the polar coordinate conversion circuit (18), information on the outline of the wipe pattern is output from the wipe pattern memory (10). And this wipe pattern memory (10)
A predetermined numerical value or a modulation signal is added to the output signal, and a wipe pattern signal is generated according to this signal and the output signal of the polar coordinate conversion circuit (18).

〔Example〕

Prior to the description of the embodiments, the principle of the present invention will be described below.

FIG. 3 is an explanatory diagram of a polar coordinate expression of a wipe pattern which is a principle of the present invention.

In the figure, W2 indicates a wipe pattern, and in this example, it is a case of a heart shape. Then, P ₀ is a reference point located in the wipe pattern W2, a straight line extending from the reference point P ₀ to the contour of the wipe pattern W2 are all in that it does not intersect only at the outline and one place of wipe pattern W2 is there. l is shown in FIG from the reference point P _0, which is a reference line extending in the right direction. P ₁ is straight l ₁ extending from the reference point P ₀ to the contour of the wipe pattern W2 is a point which intersects the contour of the wipe pattern W2. The polar coordinate data of the wipe pattern W2 is a straight line l ₁
, An angle θ formed with the reference line l, a reference point P ₀ and an intersection P ₁
And r.

Figure 4 is the angle θ shown in FIG. 3 as an address AD, a diagram illustrating a storage example of a polar coordinate data storing the distance r between the reference point P ₀ and the intersection P ₁ as data. The example of FIG. 4 is a case where the address AD is 2 ¹² = 4096.

In this case, the address AD is 2 ¹² address, the orthogonal coordinates as shown in FIG. 5 (x, y) is the (13-bit, 13-bit), data r is Expressed this in polar coordinates, 2 ¹³ × 2
^Since the radius of the circle inscribed in the square of size ¹³ is ¹³ , the data r is 12 bits. Therefore, the capacity of the graphics memory is 12 bits × 2 ¹² address ≒ 48k bits.

FIG. 1 is a block diagram showing an embodiment based on the principle of the present invention described above.

In the figure, the orthogonal coordinates (x, y) is the coordinate transformation circuit (6), the reference point P ₀ as described above are coordinate transformation such that the origin. The signals X and Y that have been subjected to the coordinate conversion are supplied to an angle calculation circuit (7) and a distance calculation circuit (8) that constitute a polar coordinate conversion circuit (18). Then, the angle calculation circuit (7) calculates the angle data θ _s = tan from the supplied signals X and Y.
^-1 (Y / X) is calculated. Then, the obtained angle data θ
_s is supplied to the addition circuit (9). In the addition circuit (9), when a figure is to be rotated, an address offset value which is information on the angle to be rotated is added. Then, through this addition circuit (9), the angle data θ _s is
It is supplied to the graphic memory (10) as address data.

This memory (10) has polar coordinate data (FIG. 4) as described above. Accordingly, the distance data r corresponding to the supplied angle theta _s is read from the graphic memory (10). Subsequently, the distance data r is multiplied by a predetermined constant in a multiplication circuit (15) and then supplied to an addition circuit (11), added to a constant R generated from a constant generation circuit (13), and added. The value (r + R) is supplied to one input terminal of the comparison circuit (12). To the other input terminal of the comparator circuit (12), the distance calculating circuit (8) the reference point P ₀ and the coordinates calculated by (X, Y) the distance between the points,
Ie Is supplied. Then, in the comparison circuit (12), “1” if r + R ≧ Z, “0” if r + R <Z
Is output.

In this configuration, it is assumed that the memory (10) stores distance data r that becomes a square wipe pattern WB as shown in FIG. 8 (B).

Then, when R = 0, the data r in the memory (10)
Is supplied to the comparison circuit (12) as it is, so that the wipe pattern output of the comparison circuit (12) becomes the pattern WB of FIG. 8 (B).

In this case, the distance data r is calculated by the multiplication circuit (15).
By changing the value of the coefficient k by which is multiplied, the size of the square pattern WB can be changed as shown in FIG.

When R> 0, as shown in FIG. 6, this constant R is added for each data r in the adding circuit (11), that is, as shown on the right side of FIG. θ
Regardless of _s , a constant value R (shown by a solid line) is added to data r (shown by a broken line), so that each side of the quadrilateral is curved outward as shown in FIG. 8 (C). This becomes the wipe pattern signal WC.

On the other hand, when R <0, this constant R is subtracted from each data r, and conversely to the case where R> 0, FIG.
As shown in FIG. 7, a thread-wound wipe pattern signal WA in which each side of the quadrilateral is curved inward.

In the case of R> 0 or R <0, if the ratio between the product kr of the coefficient k and the data r and the constant R is kept constant and the values of the constant R and the coefficient k are changed, the wipe pattern WC or WA becomes Only the size can be changed without changing the shape.

Alternatively, the constant R is, for example, R <0 for each field.
If so increases to R> 0 from during the conversion of the screen, it is possible for example to from wipe pattern W _A of Figure 8 to the pattern W _B then patterned W _C will change the shape of the wire pattern .

Next, FIG. 2 shows an example of an apparatus in which a contour of a wipe pattern is given a wavy change in a radial direction as shown in FIG.

In the case of the example of FIG. 2, a modulation signal generating circuit (14) is provided instead of the constant generating circuit (13) of the example of FIG. Then, the angle data θ from the polar coordinate conversion circuit (18)
_s is supplied to a signal generation circuit (14) via an addition circuit (9), and a modulation signal αα = Asin nθ _s (where A and n are arbitrary constants) is extracted from the signal generation circuit (14). , which is supplied to the adding circuit (11), and, in the adder circuit (11), the modulated signal Asin n.theta _s and the distance data r from the figure memory (10) is added, the addition output comparator circuit (12) Supplied to

Therefore, assuming that the memory (10) stores, for example, distance data r that becomes a circular wipe pattern W4 as shown in FIG. 7, as shown in FIG.
Since a modulation signal α (also shown by a solid line) is added for each (shown by a broken line on the right side in the figure), as shown in the figure, a wiper in which the distance r + α between the contour and the reference point P ₀ changes periodically according to the angle A pattern W _mm can be obtained.

In this case, by changing the value of the coefficient k supplied to the multiplication circuit (15), the size of the wipe pattern W _mm can be changed.

Note that the wipe pattern W _mm shown in FIG. 7 is an example in which n is set to 4;

Further, n is not an integer but may be a number including a decimal part.
In this case, since 360 ° is not the end point of the cycle of the change of the modulation signal, wipe pattern W _mm can be rotated.

Further, by changing the value of the constant A, the magnitude of the wavy change of the contour of the wipe pattern can be changed.

The modulation signal to be added to the distance data r is not limited to a sine wave signal, but may be a triangular wave signal, a sawtooth wave signal, or the like.

Further, by combining the above-described FIG. 1 example and FIG. 2 example, a constant R and a modulation signal Asin n are added to the distance data r.
by adding theta _s, it may generate a wipe pattern.

According to the above-described embodiment, since the wipe pattern is represented by polar coordinates and the data indicating the wipe pattern is compressed, there is an effect that the capacity of the memory for storing the wipe pattern can be reduced.

Further, since the constant R is added to the distance data r of the polar coordinates, the contents of the graphic memory can be changed without changing the contents.
The shape of the wipe pattern can be easily changed.

Further, since a modulation signal such as a sine wave signal is added to the distance data r of the polar coordinates, it is possible to easily generate a wipe pattern whose contour changes in a wavy manner in the radial direction.

Furthermore, since the wipe pattern is expressed in polar coordinates, the wipe pattern can be rotated by simply adding an offset value to the angle θ _s and performing no complicated calculations using trigonometric functions as in the case of rectangular coordinates. can do.

[Effects of the Invention] According to the present invention, the wipe pattern is represented by polar coordinates, and the data indicating the wipe pattern is compressed, so that the memory capacity for storing the wipe pattern can be reduced. .

Further, since the numerical data is added to the distance data r of the polar coordinates, the shape of the wipe pattern can be easily changed without changing the contents of the graphic memory.

[Brief description of the drawings]

1 and 2 are block diagrams showing an embodiment of the present invention, FIGS. 3 to 5 are explanatory diagrams of the principle of the present invention, FIG. 6 is an explanatory diagram of the example of FIG. 1, and FIG. Is an explanatory view of the example in FIG. 2, and FIG.
FIG. 9 is a diagram showing a change in a wipe pattern, and FIGS. 9 to 15 are diagrams showing a conventional technique. (10) is a figure memory, (11) is an addition circuit, (13) is a constant generation circuit, (14) is a modulation signal generation circuit, and (18) is a polar coordinate conversion circuit.

Claims (2)

(57) [Claims] A first angle data indicating a contour of a wipe pattern in a polar coordinate system and the first distance data among the first distance data corresponding to the first angle data;
A storage unit stored at an address corresponding to the first angle data; and a second angle data and a second distance data indicating a position of each pixel on the display screen in the polar coordinate system. Pixel position data generating means for supplying the angle data of No. 2 to the storage means as data indicating the address of the storage means; and supplying the second angle data from the pixel position data generation means to the storage means. Adding means for adding predetermined numerical data to the first distance data read from the storage means, and first distance data after addition output from the adding means and output from the pixel position data generating means Above the second
And a wipe pattern data generating means for generating wipe pattern data based on the magnitude relationship of the distance data. 2. A wipe pattern generating apparatus according to claim 1, wherein said predetermined numerical data changes in size in accordance with a value of said second angle data.