JP2622622B2 - Scan line number conversion control method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Overview] A simple configuration of a scanning line number conversion control system for mutually converting the number of scanning lines between various television standard systems such as the NTSC system and the PAL system and the common intermediate format system. In order to reduce the delay and to convert the number of scanning lines, a scanning line number conversion control method for converting the number of scanning lines from one of various television standard systems and a common intermediate format system to the other. A control unit for controlling the line memory and the selector, wherein the control unit sets the product of the number of pixels on one scanning line and the number of scanning lines in the one and the other systems to be equal, and The pixel data selected so that the number of pixels on one scanning line of the one and the other systems is equal to the memory is written into the memory, and the selector is driven by the selector at a period according to the ratio of the number of scanning lines of the one and the other systems. Performing insertion or deletion of scan lines, by reading the pixel data from the line memory, and configured to convert the number of scanning lines of the method of the one and the other.

[Industrial applications]

The present invention relates to a scanning line number conversion control system for mutually converting the number of scanning lines between various television standard systems such as an NTSC system and a PAL system and a common intermediate format system.

Television system NT in Japan, US, Canada, etc.
SC (National Television System Committee) method,
It has a configuration of 525 scanning lines, 60 fields, and 30 frames, and has a PAL (Phase Alternate) in Germany and the United Kingdom.
The Line) system and the SECAM system in France and the like have a configuration of 625 scanning lines, 50 fields, and 25 frames.

Such a common intermediate format (Common Intermediate
Format) was proposed by CCITT (International Telegraph and Telephone Consultative Committee). This common format (CIF) system is defined as having 288 effective scanning lines and a maximum frame number of 29.97 / sec. Therefore, to convert between various television standard formats and the Common Intermediate Format (CIF) format,
It is desired that the number of scanning lines can be converted easily and at high speed.

[Conventional technology]

As described above, since various television standard systems have different numbers of scanning lines, when mutually converting,
At least one frame of pixel data can be stored in the frame memory and converted by reading control of the frame memory, but the control configuration becomes complicated due to a difference in the number of pixels in one frame and the like.

As described above, a system for performing conversion via a common intermediate format (CIF) system without directly converting from one television standard system to another television standard system is going to be standardized as described above. Therefore, by transmitting the signal of the CIF system, the receiving side can relatively easily convert to an arbitrary television standard system. Since the number of scanning lines is also different in the conversion in this case, a configuration is adopted in which a frame memory for storing at least one frame of pixel data is provided, and the number of scanning lines is converted by reading control of the frame memory. [Problem to be Solved by the Invention] As described above, the conversion is started after at least one frame of pixel data is stored in the frame memory, and the scanning line is stored for the time required to store one frame. Number conversion will be delayed. For example, when converting from the NTSC system to the APL system, it is delayed by one frame to convert from the NTSC system to the CIF system, and is further delayed by one frame to convert from the CIF system to the PAL system. Minutes later. Thus, there is a disadvantage that the conversion processing delay is large.

SUMMARY OF THE INVENTION An object of the present invention is to convert the number of scanning lines with a simple configuration and with a reduced delay. [Means for Solving the Problems] The conversion of the number of scanning lines between the television standard system and the CIF system will be described with reference to FIG.

A control unit for controlling a line memory 1 and a selector 2 in a scanning line number conversion control system for converting the number of scanning lines from one of various television standard systems and a common intermediate format (CIF) system to the other. 3 and the control unit 3
Sets the number of pixels and the number of scanning lines so that the product of the number of pixels on one scanning line and the number of scanning lines in one and the other methods becomes equal. The pixel data of the smaller number of pixels on the scanning line is written to the line memory 1 and the pixel data is read from the line memory 1 so that the number of pixels on one scanning line of one and the other becomes the number of pixels on one scanning line. A configuration is provided in which the presence or absence of addition of invalid pixel data is selected, and the insertion or deletion of dummy scanning lines is controlled by the selector 2 in a cycle according to the ratio of the number of scanning lines in one system to that in the other system. .

The control unit 3 outputs a line counter and a pel counter that count up in synchronization with the frame synchronization signal, and outputs a control signal that controls the line memory 1 and the selector 2 by being accessed based on the count contents of the line counter and the pel counter. And a read-only memory.

[Action]

According to claim 1, when converting from a small number of scanning lines, for example, NTSC, to a large number of scanning lines, for example, CIF,
Assuming that the number of pixels on a scanning line is 858 for the NTSC system and 715 for the CIF system, the number of scanning lines is 525 for the NTSC system and 630 for the CIF system, so the product of the number of pixels and the number of scanning lines is 450 450. Become equal. The control unit 3 writes 715 pixel data, which is the same as the number of pixels on one scanning line of the CIF system, into the line memory 1 among the pixel data on one scanning line of the NTSC system, and sets a dummy scanning line by the selector 2 to the NTSC system and the CIF system. The period according to the ratio of the number of scanning lines to the method, that is, by inserting one dummy scanning line for every five scanning lines and reading from the line memory 1,
The number of scanning lines can be converted from NTSC to CIF without losing necessary information.

When converting from a CIF system with a large number of scanning lines to an NTSC system with a small number of scanning lines, for example, the CIF is stored in the line memory 1.
Pixel data is written, a period according to the ratio of the number of scanning lines, that is, one of the six scanning lines is deleted as a dummy scanning line, and one line of the NTSC system is deleted from the line memory 1.
By reading during a period corresponding to the difference between the number of pixels in the scanning line and the number of pixels in the CIF method, the number of pixels on one scanning line can be reduced to 85.
It can be converted to the NTSC system with 8 and 525 scanning lines.

According to a second aspect of the present invention, a write control signal or a read control signal according to a ratio of the number of scanning lines when converting from one system to the other system is stored in a read only memory, and a frame synchronization signal is stored in the read only memory. Synchronously, the writing and reading of pixel data to and from the line memory 1 are controlled for the scanning lines and pixels, and the selector 2 is controlled to insert or delete dummy scanning lines, thereby converting the number of scanning lines. be able to.

〔Example〕

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

FIG. 2 is a block diagram showing a main part of an embodiment of the present invention.
Is a line memory, 12 is a selector, 13 is a control unit, 14 is a line counter, 15 is a pel counter, 16 is a read only memory (ROM), SL is a selection control signal, RE is a read enable signal, RR is a read reset signal, WE is a write enable signal, WR is a write reset signal, and SYN is a frame synchronization signal.

The line memory 11 is configured by a first-in first-out (FIFO) memory, and image data is written when the write enable signal WE from the control unit 13 is set to “1”, and the read enable signal RE is set to “1”. It is read when it becomes 1 ". The selector 12 outputs the selection control signal SL
2 shows a common circuit when inserting a dummy scanning line of “0” and deleting a dummy scanning line. However, insertion and deletion of the dummy scanning line can realize both functions by changing the contents of the ROM. The line counter 14 and the pel counter 15 synchronize with the frame synchronizing signal SYN, count pixel data (sampling clock signal) by the pel counter 15, and indicate the pixel position on one scanning line by the count content. The content of the counter indicates the scanning line position, and the control signal is read by accessing the read-only memory 16 based on the count contents of the line counter 14 and the pel counter 15.

For example, in the NTSC system, when sampling is performed at a sampling frequency of 13.5 MHz, the product of the number of pixels on one scanning line and the number of scanning lines is 858 × 525 = 450450. The number of scanning lines is 630
Also in the CIF conversion signal format of this book, if the number of pixels on one scanning line is determined to be the same as this, the result is 715 including effective pixels. Therefore, as shown in FIG.
When converting from the C method to the CIF method, 715 pixel data including effective pixels are selected from 858 pixel data of each scanning line, and one dummy scanning line is inserted for every five scanning lines. When converting from the CIF system to the NTSC system, 143 invalid pixel data are added to 715 pixel data of each scanning line to make 858 pixel data, and one scanning line is converted from six scanning lines. This will be deleted as a dummy scanning line.

Fig. 4 is an explanatory diagram of the format.
The conversion signal format and the number of scanning lines (vertical axis) and the number of pixels (horizontal axis) are shown. In the NTSC system, the number of effective scanning lines in the effective data area of the odd field and the even field constituting one frame is 240, and the number of effective pixels on one scanning line is 704. The number of effective scanning lines in the effective data area of the odd field and the even field of the signal format for CIF conversion is 288, and the number of pixels on one scanning line of the NTSC system is 8 pixels.
From 58, when the number of pixels on one scanning line of the CIF conversion signal format is set to 715, the number of effective pixels of the NTSC system is more than 704, so the necessary image information is held and the number of scanning lines is converted. It can be carried out.

5A and 5B are diagrams for explaining the NTSC / CIF conversion operation of the embodiment of the present invention. FIG. 5A shows a write enable signal WE, and FIG. 5B shows a write reset signal W at a timing corresponding to a horizontal synchronization signal.
R, (c) is an input signal of the NTSC system, (d) is pixel data to be written to the line memory 11, (e) is pixel data read from the line memory 11, and (f) is a read enable signal R.
E and (g) show an example of the read reset signal RR.

When converting the number of scanning lines from the NTSC system to the CIF system, the write enable signal WE shown in (a), the write reset signal WR shown in (b), and (f)
, A read reset signal RR shown in (g), and a selection control signal (not shown) for inserting the dummy scanning line DL. In this case, the read-only memory 16 is accessed and read based on the count contents of the line counter 14 and the pel counter 15.

When the pixel data of the scanning lines L5 to L9 of the NTSC system is added to the line memory 11 composed of a FIFO memory as shown in FIG. 3C, after the first 124 pixels of the 858 pixels of each scanning line L5 to L9, As shown in (a), the write enable signal WE is "1".
Since it becomes “0” 19 pixels before the tail of 858 pixels, 7
Data of 15 pixels is written into the line memory 11 as shown in FIG. Also, the read enable signal RE becomes "0" as shown in (f) in synchronization with the beginning of the scanning line L5, reading from the line memory 11 is stopped, and the selector 12 is controlled by the selection control signal SL. Selectively outputs “0”. That is, dummy scanning lines DL for 715 pixels are output as shown in FIG.

After the output of the dummy scanning line DL, the read enable signal
RE becomes "1", reading from the line memory 11 is started, and pixel data on the scanning line L5 is read. In addition, the selector 12 is controlled by the selection control signal SL to selectively output the pixel data read from the line memory 11. At that time, the pixel data of the scanning line L5 written in the line memory 11 is read with a delay of 591 pixels from the head of the scanning line L5.

After that, the read enable signal RE becomes “1”
, Sequentially from the line memory 11 to the scanning lines L6 to
The pixel data of L9 is read. In that case, line memory
448, respectively from the beginning of each scanning line L6 to L9 written to 11
The pixel data of each of the scanning lines L6 to L9 is read out with a delay of 305, 162, and 19 pixels. After the pixel data of the scanning line L9 is read out, the dummy scanning line DL is inserted. That is, one dummy scanning line DL is inserted for every five scanning lines, and the number of NTSC / CIF scanning lines is changed as shown in FIG. The conversion of the number of scanning lines is performed with a delay.

6A and 6B are views for explaining the CIF / NTSC conversion operation according to the embodiment of the present invention. FIG. 6A shows a write enable signal WE, FIG. 6B shows a write reset signal WR, and FIG.
Pixel data of the F system, (d) pixel data read from the line memory 11, (e) pixel data converted to the NTSC system, (f) an example of the read enable signal RE, and (g) an example of the read reset signal RR. Is shown.

From the read-only memory 16 of the control unit 13, a write enable signal WE shown in (a), a write reset signal WR shown in (b), a read enable signal RE shown in (f),
The read reset signal RR shown in (g) is read. Each such signal is sent to the line counter 14 and pel counter 15
Since the read-only memory 16 is accessed and read based on the contents of the count, it is sufficient to provide the read-only memory 16 corresponding to the method to be converted.

In this case, the number of scanning lines is converted by deleting one of the six scanning lines as a dummy scanning line. Therefore, pixel data is input to the line memory 11 via a selector. Although pixel data corresponding to the dummy scanning line can be deleted, this embodiment shows a case where the dummy scanning line is deleted by the write enable signal WE.

The write enable signal WE is applied to the scanning line as shown in FIG.
"1" is set for L5 to L9, but the next is the dummy scanning line DL.
Is set to “0”. Therefore, the line memory 11 has
As shown in (c), data of 715 pixels on each of the scanning lines L5 to L9 is written, and no pixel data is written during a period corresponding to the dummy scanning line DL. Then, as shown in (f), the read enable signal RE becomes "1" with a delay of 19 + 124 pixels from the head of the scanning line L5 to be written into the line memory 11, so as shown in (d), The pixel data of L5 to L9 is read. Then, by inserting invalid pixel data of 19 + 124 pixels, it is possible to convert to the number of NTSC scanning lines of 858 pixels per scanning line shown in (e). Also in this case, when the reading of the pixel data of the scanning line L9 is completed, the NTSC scanning line L9 is formed. Accordingly, the number of scanning lines is converted with a delay of at most one scanning line.

The above embodiment shows the case of NTSC → CIF conversion and its inverse conversion, in which filtering is performed after conversion of the number of scanning lines. In other television standard systems, the present invention can be applied to conversion of the number of scanning lines. Control unit
13 can have other logical configurations, for example,
The read only memory 16 is a random access memory,
The number of scanning lines can be converted by writing a control signal corresponding to the conversion method in advance by a higher-level processor or the like.

〔The invention's effect〕

As described above, according to the present invention, the product of the number of pixels on one scanning line and the number of scanning lines in one system and the other system is set to be equal to each other, and the line memory 1 having the larger number of scanning lines is stored in the line memory 1. By writing pixel data of the number of pixels on a scanning line, inserting or deleting a dummy scanning line at a period according to the ratio of the number of scanning lines, and reading out the pixel data, the conversion of the number of scanning lines is performed. Since the capacity of the line memory 1 is sufficient for about two scanning lines, there is an advantage that the circuit scale is reduced. Further, there is an advantage that the conversion processing can be performed with a delay corresponding to the maximum scanning line and the control thereof is easy.

[Brief description of the drawings]

FIG. 1 is a diagram for explaining the principle of the present invention, FIG. 2 is a block diagram of a main part of an embodiment of the present invention, FIG. 3 is a diagram for explaining scanning line conversion, FIG. 4 is a diagram for explaining format, and FIG. Example of NTSC
FIG. 6 illustrates the CIF / NT conversion operation according to the embodiment of the present invention.
FIG. 4 is an explanatory diagram of an SC conversion operation. 1 is a line memory, 2 is a selector, and 3 is a control unit.

 ────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Kiichi Matsuda 1015 Kamiodanaka, Nakahara-ku, Kawasaki City, Kanagawa Prefecture Inside Fujitsu Limited (56) References JP-A-3-285483 (JP, A)

Claims (2)

(57) [Claims] A line memory (1) and a selector (2) in a scanning line number conversion control system for converting the number of scanning lines from one of various television standard systems and a common intermediate format system to the other. And a control unit (3) for controlling the operation of the first and second methods.
The number of pixels and the number of scanning lines are set so that the product of the number of pixels on the scanning line and the number of scanning lines are equal. Is written to the line memory (1), and the pixel data is read from the line memory (1), so that the number of pixels on one scanning line in the one and the other system is obtained.
A configuration in which the presence or absence of addition of invalid pixel data is selected, and the insertion or deletion of dummy scanning lines is controlled by the selector (2) at a period according to the ratio of the number of scanning lines of the one and the other types. A scanning line number conversion control method, comprising: 2. The control section (3), wherein a line counter and a pel counter which count up in synchronization with a frame synchronization signal, and which are accessed by the count contents of the line counter and the pel counter, write and read pixel data. 2. The scanning according to claim 1, further comprising: a read-only memory that outputs a control signal for controlling the line memory that performs the read operation and the selector that performs insertion or deletion of the dummy scanning line. Line number conversion control method.