JPH0984055A - Scanning conversion method for video signal and scanning converter for video signal used for it - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the cost for a scanning converter. SOLUTION: The converter is provided with a scanning conversion decoder 1 separating a video signal into luminance signal data and chrominance signal data, a multiplexer 4 multiplexing the luminance signal data and the chrominance signal data, a memory 2 storing the multiplexed data, a demultiplexer 5 demultiplexing the data in the memory 2 into the luminance signal data and the chrominance signal data, and a scanning conversion encoder 3 to put together the demultiplexed luminance signal data and the chrominance signal data to generate a video signal, a discrimination circuit 6 using the chrominance signal data to discriminate the presence of an overlay display and the multiplexer 6 multiplexes the data and the demultiplexer 4 demultiplexes the data based on the discrimination circuit 6.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a scan conversion method for displaying a video signal on a display device of a scan system different from the scan system and a scan converter used for the same, and particularly to a monochrome image signal. It is used for scan conversion of a video signal formed by superimposing information signals such as monochrome or color characters and figures.

[0002]

2. Description of the Related Art Conventionally, there are various scanning methods for display devices. For example, the color television broadcasting includes the NTSC system and the PAL system, and the computer system includes the VGA system and the SVGA system. In the presence of these various scanning methods, when the video signal and the scanning method of the display device for displaying the video signal are different from each other, the video signal is converted into the scanning method of the display device by a scan converter.

Conventionally, overlaying of characters, figures, etc. on the image has been performed in various measuring instruments and the like. In this case, superimpose information signals such as characters and figures to be overlaid on the image signal.
A superimposing device is used. Then, for example, when the video signal output from the superimposing device and the scanning system of the display device for displaying the video signal are different from each other, for example, the output video signal of the superimposing device is an NTSC video signal and the display device is a PAL system. In the case of inputting the above video signal, the above-mentioned scan converter is inserted between the superimposing device and the display device. 3 and 4 show an example of a conventional scan converter, and FIG.
RG using one color signal E _R , E _G , E _B (three-source color signal)
B system, FIG. 4 shows luminance signal E _Y and color difference signals E _U , E
_It is a YUV system that uses _V. The circuit configuration of each scan converter will be described below.

The RGB type scan converter of FIG. 3 converts an input NTSC video signal into three color signals E _R , E _G and E.
_The NTSC decoder A for decomposing into _B, and the digital color signal data D _R , D for the decomposed color signals E _R , E _G , E _B
G, and three A / D converter B that converts the D _B, and the color signal data D _R, D _G, 1 frame the respective D _B (or one field) three frame memories C to be recorded, Color signal data D _R , D _{G of} the frame memory C,
Converting D _B into analog color signals E _R , E _G , E _B 3
PAL encoder E that combines two D / A converters D and color signals E _R , E _G , and E _B as PAL video signals
A write control circuit F for controlling writing to the frame memory C by the A / D converter B;
A read control circuit G for controlling the reading from the frame memory C by the A converter D.

The YUV scan converter shown in FIG. 4 is an NTSC decoder A for decomposing an input NTSC video signal into one luminance signal E _Y and two color difference signals E _U and E _V.
And the decomposed luminance signal E _Y and color difference signals E _U and E _V into digital luminance signal data D _Y and color difference signal data D
_U, to the three A / D converter B that converts the D _V, luminance signal data D _Y and the color difference signal data D _U multiplexed in the multiplexer H, 1 frame the D _V (or one field) can be recorded Two frame memories C, and luminance signal data D _Y of the frame memory C and color difference signal data D _U and D _V decomposed by the demultiplexer I are converted into analog luminance signals E _Y and color difference signals E _U and E _V 3 D / A converter D and luminance signal E _Y and color difference signal E
_U, and PAL encoder E for synthesizing E _V in PAL video signal, a write control circuit F for controlling the writing into the frame memory C by the A / D converter B, and the frame memory C by the D / A converter D And a read control circuit G for controlling the read of the.

In recent years, a digital decoder has been put into practical use for a YUV scan converter. In this case, FIG.
Since the A / D converter B is arranged in front of the digital decoder A as shown in (3), only one A / D converter B is required for YUV.

[0007]

However, the above-mentioned scan converter has the following problems. Each of the scan converters described above is compatible with full color, and is equipped with a large amount of frame memories and the like for this, and is expensive. However, in a device used for normal measurement or the like, it is often sufficient if a character, a figure, or the like can be overlay-displayed on a monochrome image in monochrome or about 8 colors. In this case, an expensive scan converter is used even for a device that does not require full color, which is a waste.

The object of the present invention is to be suitable for use in a measuring instrument or the like which does not require full color, and it is possible to superimpose, for example, a color character graphic signal of up to 3 bits on a monochrome image at low cost. An object is to provide a simple scan conversion method and a scan converter.

[0009]

According to a first aspect of the present invention, there is provided a video signal scan conversion method, as shown in FIGS.
Writing data constituting a video signal, which is formed by superimposing an information signal such as monochrome or color characters and figures on a monochrome image signal, into the memory 2, and reading the written data from the memory 2 based on a predetermined scan conversion procedure. In the scan conversion method for converting the scanning method of the video signal into a different scanning method, the luminance signal data D _Y and the color signal data D _R , D _G and D _B forming the video signal are multiplexed to form one memory 2 To the luminance signal data D _Y and the color signal data D _R ,
It is characterized in that it is decomposed into D _G and D _B.

According to a second aspect of the present invention, in the video signal scanning conversion method, a video signal obtained by superimposing an information signal such as monochrome or color characters or figures on a monochrome image signal is decomposed into some data. A scan conversion method for converting the scanning method of the video signal into a different scanning method by writing the decomposed data to the memory 2 respectively, and reading the written data from the memory 2 based on a predetermined scanning conversion procedure and synthesizing the read data. , The video signal is decomposed into luminance signal data D _Y and three color signal data D _R , D _G , D _B , and the decomposed luminance signal data D _Y and color signal data D _R ,
D _G and D _B are multiplexed and written in one memory 2, and the data read from the memory 2 is decomposed into luminance signal data D _Y and color signal data D _R , D _G and D _B, and these luminance signal data The feature is that D _Y and color signal data D _R , D _G , and D _B are combined.

According to a third aspect of the present invention, the scan conversion method for a video signal is characterized in that the color signal data D _R , D _G , and D _B are each 1 bit.

According to the fourth aspect of the present invention, in the video signal scanning conversion method, the presence / absence of overlay display is determined using the color signal data D _R , D _G , D _B, and only when the overlay display is present. , The color signal data D _R , D _G , and D _B are multiplexed with the luminance signal data D _Y and written in the memory 2.

According to a fifth aspect of the present invention, in the video signal scan converter, a video signal obtained by superimposing an information signal such as a monochrome or color character or graphic on a monochrome image signal is passed through the scan conversion decoder 1. Decomposed into several data,
Each of these is written in the memory 2, and the written data is read from the memory 2 based on a predetermined scan conversion procedure and passed through the scan conversion encoder 3 to be combined, thereby converting the scanning method of the video signal into a different scanning method. In the video signal operation converter, the video signal is converted into luminance signal data D _Y and three color signal data D _R , D _G , D _B.
A scan conversion decoder 1 for decomposing into multiple parts, a multiplexer 4 for multiplexing the luminance signal data D _Y and the color signal data D _R , D _G , D _B , a memory 2 for writing the multiplexed data, and the same memory The demultiplexer 5 for decomposing the data No. 2 into luminance signal data D _Y and color signal data D _R , D _G , D _B, and the decomposed luminance signal data D _Y and color signal data D _R , D _G , D _B And a scanning conversion encoder 3 for synthesizing the two and generating a video signal.

A video signal scan converter according to a sixth aspect of the present invention is the video signal scan converter according to the fifth aspect.
A determination circuit 6 for determining the presence / absence of overlay display using the color signal data D _R , D _G , D _B is provided, and the data multiplexing of the multiplexer 4 and the data decomposition of the demultiplexer 5 are performed based on the determination circuit 6. It is a feature.

[0015]

First Embodiment FIGS. 1 and 2 are block diagrams showing an embodiment of a scan converter according to the present invention. FIG. 1 shows an outline of the circuit of the scan converter, and FIG. 2 shows its details.

This scan converter PAL receives an input NTSC video signal (NTSC composite video signal).
The video signal is converted into a video signal (PAL composite video signal) and output. In this case, the NTSC video signal is a monochrome image signal on which signals such as characters and figures for overlay display are superimposed, and the superimposed information is 3-bit color (monochrome is also possible).

The scanning conversion decoder 1 in FIG. 1 uses the above-mentioned NTSC video signal as a luminance signal E _Y for forming a monochrome image and 3 for forming an overlay display.
The color signals E _R , E _G , and E _B are separated and output. As shown in FIG. 2, the scanning conversion decoder 1 separates an NTSC video signal into a luminance signal E _Y and a color difference signal E _C by a Y / C separation circuit including a trap 10 and a high pass filter 11. Of these, the luminance signal E
_Y is output as it is, and the luminance signal E _Y and the color difference signal E _C are N
The TSC decoder IC12 uses the three color signals E _R , E _G , and E.
Output after separating to _B.

The A / D converter 13 in FIG. 1 has a resolution of 6 bits and converts the analog luminance signal E _Y into 6-bit digital luminance signal data D _Y and outputs it.

The comparator 14 in FIG. 1 has an analog color signal E _R output from the scan conversion decoder 1,
1-bit digital color signal data D binarized by comparing E _G and E _B with a comparison voltage generated separately.
_It outputs _R , D _G and D _B. Since the brightness of the overlay display is about 10% higher than the maximum brightness of the monochrome image, it is desirable to set the comparison voltage to an intermediate value between the overlay display brightness and the maximum brightness of the monochrome image.

The OR gate (decision circuit) 6 in FIG.
Is for determining whether or not the video signal has an overlay display. This OR gate 6 corresponds to the comparator 1
3 color signal data D _R , D _G , D _B
Is output, and the bit signal "1" is output when there is an overlay display, and the bit signal "0" is output when there is no overlay display. If the input video signal has an overlay display, there are three color signals E _R , E _G ,
Since at least one of E _B has the maximum brightness, and therefore, the bit signal is output from any one of the three comparators 14, the bit signal output from the OR gate 6 (hereinafter referred to as a switching signal VG). The presence or absence of overlay display can be determined by.

The multiplexer 4 in FIG. 2 inputs the luminance signal data D _Y of the A / D converter 13 and O
The color signal data D _R , D _G , and D _B of the R gate 6 are multiplexed. This multiplexing is performed based on the switching signal VG output from the OR gate 6, and based on the bit information of the signal VG, 6-bit luminance signal data D _Y and 3-bit color signal data D _R , D _G , D _B is switched and multiplexed. Specifically, in overlay display, a total of 4 bits of 3 bits from the three comparators 14 and 1 bit of the switching signal VG are written in the memory 2 described later, and in non-overlay display, the luminance signal data E _Y A total of 7 bits of 6 bits and 1 bit of the switching signal VG is written in the memory 2 described later.

Memory (frame memory) 2 in FIG.
Is a serial IN / serial OUT type. The frame memory 2 has a 7-bit data input port which is responsible for data input from the multiplexer 4 and a 7-bit data output port which is responsible for data output to the demultiplexer 5, and is also a port for inputting control signals. have. As the control signal, a write address reset signal RSTW and a data write clock WC are used.
There are K, a read address reset signal RSTR, and a data read clock RCT. The write side control signal is NT generated by the write control circuit 15 in FIG.
The signal is synchronized with the SC system. The read side control signal is a signal generated by the read control circuit 16 in FIG. 2 and synchronized with the PAL system. The frame memory 2 is ORed with the data from the multiplexer 4.
The switching signal VG from the gate 6 is written.

The demultiplexer 5 shown in FIG. 1 converts the data read from the frame memory 2 into 6-bit luminance signal data D _Y and 3-bit color signal data D _R , D _G in accordance with a switching signal VG included in the data. Decomposes into D _B. The output port of the demultiplexer 5 has an output of "φ" when it is not selected.

The D / A converter 17 in FIG. 1 converts 6-bit digital luminance signal data D _Y into an analog luminance signal E _Y.

The scan conversion encoder 3 in FIG.
As shown in FIG. 2, a PAL encoder IC 18 and a superimpose IC 19 are provided, and the PAL encoder I
C18 is a PA of monochrome image for the input luminance signal E _Y.
The L composite video signal is converted and output, and the superimposing IC 19 outputs the color signal data D _R , D _G , D _B.
If there is, the PAL composite video signal is superimposed on the color signal data D _R , D _G and D _B to output the PAL composite video signal for overlay display.

Next, an example of the scan conversion method of the video signal of the present invention will be described with reference to the scan converter. The NTSC video signal with the overlay display is input to the scan converter of FIG. 2 and the video signal is decomposed by the scan conversion encoder 1 into one luminance signal E _Y and three color signals E _R , E _G and E _B. To do. The brightness signal E _Y is converted into brightness signal data D _Y by the A / D converter 13, and the color signals E _R , E _G and E _B are converted into color signal data D _R , D _G and D _B by the comparator 14.
The obtained color signal data D _R , D _G , D _B are OR gates 6.
Then, the OR gate 6 generates a switching signal VG indicating the presence / absence of overlay display. The luminance signal data D _Y and the color signal data D _R , D _G , D _B are input to the multiplexer 4, and the luminance signal data D is generated by the switching signal VG.
These signals are multiplexed while switching _Y and color signal data D _R , D _G , and D _B. The multiplexed luminance signal data D _Y and color signal data D _R , D _G , D _B are written in the frame memory 2 together with the switching signal VG. This writing is controlled by the synchronization signal of the writing control circuit 15. When there is no overlay display, the luminance signal data D _Y and the switching signal VG are written in the frame memory 2.

The data written in the frame memory 2 is read in synchronization with the sync signal of the read control circuit 16. The read data is separated by the demultiplexer 5 into a digital luminance signal D _Y and digital color signals D _R , D _G and D _B based on the switching signal VG. The digital brightness signal D _Y is converted into an analog brightness signal E _Y by the D / A converter 17, and is input to the scan conversion decoder 3 together with the digital color signals D _R , D _G and D _B. Analog luminance signal E _Y
Is converted into a monochrome video PAL composite video signal by the scan conversion decoder 3, and digital color signal D _R ,
If D _G and D _B are present, they are superimposed to form a PAL composite video signal for overlay display.

[0028]

Embodiment 2 The scan conversion method of the present invention and the scan converter used for the same are the same as those of an NTSC video signal to a PA.
It can be applied to other than the scan conversion into the L video signal. For example, scanning method conversion between color televisions such as conversion from NTSC to SECAM, conversion from PAL to SECAM, conversion from VGA to NTSC, conversion from VGA to PAL, and scanning between color television and computer display. It can also be applied to method conversion and the like. In this case, the video signal input / output system encoder, decoder, write control circuit, and read control circuit can be easily replaced by appropriate circuits.

[0029]

Third Embodiment The scan conversion method of the present invention and the scan converter used therefor can be applied even when the video signal is a digital signal. For example, it can be applied to scan conversion between a full digital camera and a full digital. In this case, the video signal is the luminance signal data D _Y ,
The color signal data D _R , D _G , and D _B are transmitted to the data bus. Therefore, the scan conversion decoder 1, the scan conversion encoder 3, and the A / D converter 1 shown in FIGS.
3, the D / A converter 17 and the like are unnecessary. In this case, a circuit including the multiplexer 4, the frame memory 2, the demultiplexer 5, the write control circuit 15, the read control circuit 16 and the like can be directly connected to the image data bus.

[0030]

The scan conversion method of the present invention has the following effects. . Since the luminance signal data and the color signal data are multiplexed and recorded in the memory, it is possible to reduce the memory, the A / D converter, the D / A converter and the like. Therefore, when the scan converter is configured, the cost of the converter can be reduced. . Therefore, the cost of the device can be suppressed by using it for a measuring device or the like which does not require full color display. . In the scan conversion method of the third aspect, since the color signal data is 1 bit, the memory can be made smaller, and since the amount of information is small, the scan conversion speed does not impair the real-time property. . According to the scan conversion method of the fourth aspect, since the color signal data is not multiplexed when there is no overlay display, efficient scan conversion can be performed with a small memory.

The scan converter of the present invention has the following effects. . By using this scan converter, the price can be reduced in a device that does not require full-color display.

[Brief description of drawings]

FIG. 1 is a block diagram of an embodiment of a scan conversion method for a video signal of the present invention and a scan converter for a video signal used therefor, which is schematically shown.

FIG. 2 is a block diagram of an embodiment of a video signal scan conversion method of the present invention and a video signal scan converter used therefor, showing in detail.

FIG. 3 is a block diagram showing an example of a conventional scan converter.

FIG. 4 is a block diagram showing another example of a conventional scan converter.

FIG. 5 is a block diagram showing still another example of a conventional scan converter.

[Description of Codes] 1 Decoder for scan conversion 2 Memory 3 Encoder for scan conversion 4 Multiplexer 5 Demultiplexer 6 Judgment circuit

Claims (6)

[Claims] 1. Data for forming a video signal, which is formed by superimposing a monochrome or color information signal such as characters or figures on a monochrome image signal, is written in a memory (2), and the written data is based on a predetermined scan conversion procedure. The memory (2)
In the scan conversion method of converting the scanning method of the video signal into a different scanning method by reading from the above, the luminance signal data D _Y and the color signal data D forming the video signal
_R , D _G , D _B are multiplexed and written in one memory (2), and the data read from the memory (2) is decomposed into luminance signal data D _Y and color signal data D _R , D _G , D _B. A method for scanning and converting a video signal, characterized in that. 2. A video signal obtained by superimposing a monochrome or color information signal such as characters or figures on a monochrome image signal is decomposed into some data, and the decomposed data is written and written in the memory (2) respectively. In a scan conversion method for converting the scanning method of the video signal into a different scanning method by reading data from the memory (2) based on a predetermined scanning conversion procedure and synthesizing the data, the video signal is converted into luminance signal data D _Y. Three color signal data D _R , D _G , D
_The divided luminance signal data D _Y and the divided color signal data D _R , D _G , and D _B are multiplexed and written in one memory (2), and the data read from the memory (2) is the luminance signal data. D _Y and color signal data D _R , D _G , D _B are decomposed into luminance signal data D _Y and color signal data D _R ,
A scan conversion method for video signals, characterized in that D _G and D _B are combined. 3. The color signal data D _R , D _G , D _B are each 1
2. The scan conversion method for video signals according to claim 1, wherein the scan signals are bits. Wherein said color signal data D _R, D _G, using D _B determines whether the overlay display, only when there is an overlay display, the color signal data D _R, D _G, luminance signal D _B 4. The scan conversion method for video signals according to claim 1, 2 or 3, wherein the data is multiplexed with the data D _Y and written in the memory (2). 5. A video signal formed by superimposing an information signal such as monochrome or color characters or figures on a monochrome image signal is passed through a scanning conversion decoder (1) to be decomposed into some data, which are respectively stored in a memory. The scanning method of the video signal is written in (2), and the written data is read from the memory (2) based on a predetermined scan conversion procedure and is passed through a scan conversion encoder (3) to be combined, thereby changing the scanning method of the video signal to a different scanning method. In the video signal operation converter that converts to
A scan conversion decoder (1) for decomposing the video signal into luminance signal data D _Y and three color signal data D _R , D _G , D _B , luminance signal data D _Y and color signal data D _R ,
A multiplexer (4) for multiplexing D _G and D _B , a memory (2) for writing the multiplexed data, and data of the memory (2) for the luminance signal data D _Y and the color signal data D
Demultiplexer for decomposing into _R , D _G and D _B (5)
And the decomposed luminance signal data D _Y and color signal data D
A scan converter for video signals, comprising a scan converter encoder (3) for synthesizing _R , D _G and D _B to generate a video signal. 6. A scan converter for video signals according to claim 5,
A determination circuit (6) for determining the presence / absence of overlay display using the color signal data D _R , D _G , D _B is provided, and the data multiplexing and demultiplexer (5) of the multiplexer (4) is based on the determination circuit (6). ). A video signal scan converter characterized by performing data decomposition of (1).