JP2743775B2 - Digital special effects device coordinate conversion circuit - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a coordinate conversion circuit, and more particularly to a coordinate conversion circuit of a digital special effect device for processing a digitized video signal in real time.

[0002]

2. Description of the Related Art An example of a conventional digital special effect device is shown in FIG. In the figure, 1 is an input video signal,
Reference numeral 2 denotes an input processing unit for inputting and processing the input video signal 1;
Is a video memory for storing the processed video signal, 4 is an output processing unit for processing the output from the video memory, 5 is an output video signal output from the output processing unit 4, and 6 is a write address in the video memory 3. A write address generator for output,
Reference numeral 7 denotes a read address generator for outputting a read address to the video memory 3, 9 an address modifier for modifying the read address, 8 a basic address generator for generating the read address, and the read address generator 7 comprises an address. It comprises a decoration unit 9 and a basic address generation unit 8. An effect control unit 10 controls the read address generation unit 7.

An input video signal 1 is first applied to an input processing section 2. The input processing unit 2 performs PCM digitization of an analog signal and separates a luminance signal and a chrominance signal. The output data digitized by the input processing unit 2 is written to the video memory 3 in accordance with the addresses sequentially generated by the write address generation unit 6 in synchronization with the input video. The video data written in the video memory 3 is read in accordance with a read address to be described later, and the output processing unit 4 performs synthesis of a background image signal, synthesis of a luminance signal and a chrominance signal, etc.
Is output as

[0004] Of the above, the respective configurations of the input processing unit 2, the video memory 3, the write address generation unit 6, and the output processing unit 4 are not directly related to the present invention, and any configuration can be used.

In general, a special effect is realized by causing the read address generation unit 7 to generate addresses in a different order from the write address. That is, in FIG. 5, if the output of the basic read address generating section 8 for generating a sequential address similar to the write address is used as it is for the read address of the video memory 3 (not shown), the output video becomes the same as the input video. By changing this using the read address modification unit 9, a video output different from the input can be obtained. The effect control unit 10 is a control unit that determines the operation of the read address modification unit 9 described above.

Conventionally, a coordinate conversion circuit having a configuration shown in FIG. 2 is known as an example of this type of address modification unit.

This circuit realizes a bilinear transformation in which an affine transformation and a perspective transformation are combined in a three-dimensional space. According to the coordinate transformation circuit having this configuration, enlargement / reduction / translation / rotation Can be arbitrarily performed, and perspective transformation and transformation to an oblique coordinate system can be performed in combination.

In FIG. 2, a, b, c, d, e, f,
The twelve parameters p, q, r, s, t, and u are constants, and Xi and Yi are input coordinate values. These constants and coordinate values are multiplied by multipliers 101-108 and adders 109-108.
116, to obtain output coordinate values Xo, Yo by calculation by dividers 117 to 118.

In general, in a digital special effect device, the time allowed for calculation in units of one pixel is usually 70 to 7 times.
4 ns, and a dedicated multiplier or adder is essential for the operation. Therefore, the twelve constant parameters are calculated by a microprocessor or the like in a field time unit (16.7 ms in the case of the NTSC system) and set in the coordinate conversion circuit within the vertical blanking period, so that the coordinates are set in the display period. The conversion circuit is configured to perform the operation for each pixel. This seeks to solve both arbitrary coordinate transformation and high speed.

[0010]

According to the prior art described above, the constant parameter is changed on a field-by-field basis, and therefore, the same conversion is performed for all the pixels constituting one screen. However, there is a drawback that the effect is monotonous. You can also split one screen,
In order to apply different conversions to each of the divided parts, it is necessary to provide a dedicated conversion circuit in addition to the address conversion circuit, and there is a disadvantage that the circuit becomes complicated.

Further, even if a different conversion operation is to be performed for each pixel, it is necessary to perform the operation in a period of 70 to 74 ns per pixel. . Even if the conversion is not as fine as the conversion in pixel units, for example, even when a plurality of conversions (several sets to about several tens of sets) are realized in one screen, the pixel switching part takes the period of 70 to 74 ns. It doesn't matter what you have to do.

The present invention has been made in view of such circumstances, and provides a coordinate conversion circuit of a digital special effect device capable of implementing a plurality of coordinate conversions within one screen by a simple circuit. With the goal.

[0013]

In order to achieve the above object, a coordinate conversion circuit of a digital special effect device according to the present invention comprises:
Parameter memory for storing a plurality of sets of constant parameters; effect control means for calculating a plurality of sets of constant parameters required for one field period;
Parameter selection calculation means for calculating selection data for giving the effect of rotation about the axis, and parameter address control for selecting and outputting constant parameters stored in the parameter memory using the selection data Means and coordinate conversion means for inputting a coordinate value of a pixel of a predetermined image as an input signal and applying a selected constant parameter to perform coordinate conversion on a pixel basis, and by changing a constant parameter stored in a parameter memory, It is characterized in that the effect to be obtained is changed.

[0014]

In the coordinate conversion circuit of the digital special effect device according to the present invention, a necessary set of constant parameters held in the parameter memory is selected by using the selection data of the selection result of the parameter selection calculation means, and the coordinate conversion is performed. The coordinate conversion is performed by the means. Thereby, a plurality of different coordinate conversions can be performed in one screen according to the pixel address.

[0015]

FIG. 1 shows an embodiment of the present invention. In FIG. 1, 119 is a coordinate conversion unit, and 120 is a parameter memory. The coordinate transformation unit 119 has a configuration as shown in FIG. 2, and includes multipliers 101 to 108, adders 109 to 116,
It has dividers 117-118. Coordinate converter 119
Are the outputs of the parameter memory 120, a, b, c,
The input coordinate values Xi, Yi are coordinate-transformed using twelve parameters d, e, f, p, q, r, s, t, and u to obtain output coordinate values Xo, Yo.

The parameter address control unit 121 uses the selection result output S of the parameter selection calculation unit 122 to select a required set of constant parameters stored in the parameter memory 120 and to output the selected set from the parameter memory 120. I do.

The effect control unit 123 calculates a plurality of parameter sets required for one field period and stores them in the parameter memory 120 during the vertical blanking period. In the calculation of the parameter sets, generally, by using a high-performance microprocessor, there is no problem at all in calculating several to ten or more parameter sets within one field period.

FIG. 3 shows an example of the parameter selection operation section 122. In FIG.
2 is a divider. This configuration provides the effect of dividing the screen and performing different rotations about the X axis as shown in FIG. In FIG. 4, reference numeral 124 denotes a divided screen. When the parameter selection operation unit 122 has a configuration as shown in FIG. 3, the parameter selection operation unit 122 performs an operation of S = X / n on the selected data S based on the X coordinate and outputs the result. However, the division is performed by integer division, and N is an integer indicating the number to be divided (for example, 8 as shown in the figure), and n = (horizontal axis in the X direction ÷ N).

In this case, the selection data S changes stepwise between O and N-1 according to the value of the X coordinate. On the other hand, the parameter memory 120 stores a parameter in which the rotation angle A about the X axis is set as A = 360 degrees × S / N according to S = O to N−1. Output in response to S.

As a result, as shown in FIG. 4, the screen is divided into N pieces according to the X coordinate, and the effect of performing different rotations is obtained.

According to this embodiment, it is possible to perform a plurality of different coordinate conversions in one screen according to the pixel address, not only to obtain a special effect such as screen division, but also to obtain a parameter selection operation unit. It is very economical because special effects can be changed only by changing the software of the microprocessor of the effect control unit 123 and the effect control unit 123.

[0022]

As described above, according to the present invention, coordinate conversion means for inputting a coordinate value of a pixel, giving a constant parameter, and performing coordinate conversion on a pixel-by-pixel basis; Since it has a parameter memory for storing and a parameter selection calculating means for selecting and controlling a constant parameter stored in the parameter memory according to the coordinate value of a pixel, a plurality of coordinate conversions can be realized within one screen by a simple circuit. it can.

[Brief description of the drawings]

FIG. 1 is a block diagram showing an embodiment of a coordinate conversion circuit according to the present invention.

FIG. 2 is a diagram illustrating a coordinate conversion unit in FIG. 1;

FIG. 3 is a block diagram illustrating an example of a parameter selection calculation unit in FIG. 1;

FIG. 4 is a conceptual diagram illustrating an effect obtained by an example of the parameter selection calculation unit in FIG. 1;

FIG. 5 is a block diagram illustrating an example of a coordinate conversion circuit according to the related art.

[Explanation of symbols]

 Xi, Yi Input coordinate values Xo, Yo Output coordinate values a to f, p to u Constant parameters 119 Coordinate conversion unit 120 Parameter memory 121 Parameter address control unit 122 Parameter selection calculation unit 123 Effect control unit

Claims (2)

(57) [Claims] A parameter memory for storing a plurality of sets of constant parameters; an effect control means for calculating a plurality of sets of constant parameters required for one field period; and performing rotation about the X axis from X coordinate data. Parameter selection calculation means for calculating selection data for providing the effect, parameter address control means for controlling selection and output of a constant parameter stored in the parameter memory using the selection data, Coordinate conversion means for inputting a coordinate value of a pixel of an image as an input signal, applying the selected constant parameter and performing coordinate conversion on a pixel-by-pixel basis, and changing the constant parameter stored in the parameter memory. A coordinate conversion circuit for a digital special effect device, wherein an effect is changed. 2. The method according to claim 1, wherein the coordinate conversion means includes a, b, c, d,
e, f, p, q, r, s, t and u are constant parameters, X
Let i and Yi be input coordinate values and output coordinate values (Xo, Yo)
The coordinate transformation circuit according to claim 1, wherein: Xo = (aXi + bYi + c) / (cXi + dYi + e) Yo = (pYi + qYi + r) / (sXi + tYi + u).