JPS5831150B2 - Television standard format converter - Google Patents

Description

Detailed Description of the Invention Technical Field The present invention relates to a television standard format conversion device (hereinafter abbreviated as "TSC") that converts television signals of different television formats into standard television signals.

) relates to a device for determining whether a still image portion or a moving image portion of a television screen is displayed.

Problems with the Prior Art A television screen includes a still image portion and a moving image portion, but due to the characteristics of the human eye, resolution for still images is better than for moving images.

In order to match the characteristics of the eye, a method is used in TSC that distinguishes between the still image portion and the moving image portion of the television screen and performs interpolation appropriate for each. To do this well, a memory that can store four fields of image information is required.

Purpose of the Invention The present invention provides a television standard that uses a storage device that only stores video detection signals over one field, in addition to the conventional main storage device that stores three fields of image information, to discriminate video portions more accurately than the conventional TSC. The purpose is to provide a system conversion device.

Structure of the Invention The present invention compares image information between fields of the same type two fields apart, distinguishes between a still image portion and a moving image portion, and performs line inscription for the still image portion using information between different types of fields. , in a television standard format conversion device that performs line interpolation using information in the same type of field for a moving image portion, a moving image detection signal storage device that stores a moving image detection signal indicating the moving image portion over at least one field is read out from the main storage device. means for reading out the stored moving image detection signal in the next field following the stored field; and logic between the moving image detection signal read out in the next field and the moving image detection signal of the next field; 1. A television standard format conversion device characterized by comprising: means for calculating a sum.

Embodiment FIG. 1 is a block diagram showing an embodiment of a TSC according to the present invention.

1 is an input terminal, 2 is a synchronous separation circuit, 3 is an analog-digital conversion circuit, 4 is an input side buffer circuit, 5, 6.7
is the main memory, 8.9.10 is the output side buffer circuit, 1
1 is a switching circuit, 12.13 is a video line interpolation circuit, 1
4 is a still image interpolation circuit, 15 is a video detection circuit,
16 is a switching circuit, 17 is a field interpolation circuit, 18 is a switching circuit, 19 is a moving picture detection signal OR circuit, 20.21 is a moving picture detection signal storage device, 22 is a switching circuit, 23 is a digital-to-analog converter, 24 25 is an output terminal, 25 is an input side control circuit, 26 is a main memory control circuit, 27 is an output side control circuit, and 28 is an output side synchronization signal input terminal.

An input television signal is supplied to an input terminal 1, a synchronization signal is separated by a synchronization separation circuit 2, and the signal is supplied to an input side control circuit 25.

On the other hand, the television signal is converted into an 8-bit digital signal (hereinafter referred to as "data") by the analog-to-digital converter 3.

), each TSC with 1 field capacity
The input buffer circuit 4 has the function of arranging data in parallel in order to match the data speed to the write speed of the main memory devices 5, 6, and 7.

The operation during this time is shown in FIG.

F converts the input video signal into 1 with analog-digital converter 3.
This data is converted to 2MHz 8-bit data, and the data speed is fast, so it is stored in the main memory 5 as is.
．． Since it is not possible to write to 6 and 7, this serial data is decomposed into 12 phases in order to convert it into parallel data, and then the data is arranged as shown in H to become parallel data.

This H parallel data has a period 12 times that of F serial data.

Therefore, it is possible to match the slow write/read cycles of the main memories 5, 6, and 7.

In this example, the length of one piece of serial data F is 83 n sec, but the length of one piece of parallel data H is 1 μsec.

Assuming that the write and read cycle times of the main memories 5, 6, and 7 are 500 nsec, the time relationship between write W and read R when set on the write side (input side timing) of the main memory is shown in Figure 5 I. become that way.

However, since the timings on the write side (input side) and read side (output side) of the main memories 5, 6, and 7 are asynchronous, writing and reading are performed using the output side timing in the main memories 5, 6, and 7. I am having them do this.

Main memory write W generated from output side timing
An example of a R' and read R' cycle is shown in FIG. 5J.

In order to write the parallel data H (1 to 12) in FIG. 5 to the main memory device 8, 9 or 10 in the write cycle W2' created based on the reading side, it is necessary to hold this parallel data for a longer time. Therefore, a buffer function is necessary.

In this way, the output data of the input buffer circuit 4, which has a serial-to-parallel conversion function and a buffer function, is stored in the main storage devices 5, 6.7.
It cycles through and writes to each input field.

This situation is shown in FIG. 6 (solid lines are writing, broken lines are reading).

). M is the field appearance of the input television signal.

The inputs of a, b, c, d... are the first field (1st
), 2nd field (2nd), 1st field (1s
t), second field (2nd), etc., and are configured in this order.

N stores the data of these input fields in the main memory 5,
6.7 indicates that the data is stored in order, and indicates that, for example, the main storage device 5 stores the data of the input field of atd.

When data is read from the main storage devices 5, 6.7, three fields of data are read simultaneously, and at the time of reading, the number of fields is converted and the horizontal scanning line (hereinafter referred to as "line") is read.
That's what it means.

) and convert the television system.

The result of simultaneous reading of the data of these three fields is the sixth field.
It is shown at P in the figure.

In the ■ field of P in Figure 6, the data of the input fields a, b, and c are read simultaneously, and in the ■ field, the input bp
This shows that data of three fields of cyd are being read simultaneously.

The data written in parallel in the main memory devices 5, 6.7 is converted back to serial data in the output side buffer circuits 8, 9.10.

This situation is shown by L in FIG.

For example, R created based on the output side timing of J
The data read in the read cycle 8' is parallel for 12 samples, similar to the write parallel data H, so the state of the data once stored in the buffer circuits 8, 9 and 10 is shown in Figure 5. It shows.

The output obtained by converting this data into serial data is indicated by L.

The three fields of data read out by the output buffer circuits 8, 9, and 10 are switched and outputted by the switching circuit 11 between the temporally newest field data, the next newest field data, and the oldest field data. .

For example, in the ■ field of P in FIG. 6, the newest data among the three fields of read data is from the C field, and the oldest data is from the a field.

Since the data in the newest field and the data in the oldest field are two fields apart in time, the sixth
The a field data and the C field data of field (■) in P in the figure are made to be the first field, and since they are data of the same type of field, moving image detection is performed between these two fields.

This circuit is the moving image detection circuit 15.

Among the three read fields, the newest data and the next newest data cause distortion in the output television signal due to conversion of the number of lines, so the video line interpolation circuit 12.13 corrects the distortion Each is supplied.

On the other hand, these data are also sent to the still image line interpolation circuit 1.
4 is also supplied.

This still picture line interpolation circuit 14 performs line interpolation between fields that are temporally different within one field, so this interpolation is used for the still picture portion.

The moving image line interpolation circuits 12 and 13 perform interpolation for moving image parts.

The outputs of the moving image line interpolation circuits 12 and 13 are supplied to a field interpolation circuit 17 to correct motion distortion caused by conversion of the number of fields.

On the other hand, since the output of the still image line interpolation circuit 14 interpolates the still image portion, field interpolation, which is interpolation for motion, is not used.
supplied to

The output of the field interpolation circuit 17 is also supplied to the switching circuit 18.

This switching circuit 18 is controlled by a signal from a moving image detection signal OR circuit 19 that determines whether a still image portion or a moving image portion is present.
Data from the still image line interpolation circuit 14 or data from the field interpolation circuit 17 is selected and supplied to the digital-to-analog converter 23, and the output of the digital-to-analog converter 23 is a standard television signal output. becomes.

On the other hand, a moving image detection circuit 15 detects a moving image portion, and since this moving image detection signal can be used to judge only between still images and moving images, the amount of information of 1 bit is sufficient as a signal for each judgment element.

On the other hand, in order to store a television signal, an amount of information of 8 bits is required for one sample (element).

A moving image detection signal output from the moving image detection circuit 15 is supplied to a moving image detection signal OR circuit 19 and a switching circuit 16.

The switching circuit 16 selects the moving image detection signal storage device 20 or 21 for each field, and stores the moving image detection signal in the moving image detection signal storage device 20 or 21.

The switching circuit 22 also selects the moving image detection signal storage device 20 or 21 for each field and reads out the moving image detection signal.

The selections of the moving image detection signal storage devices 20 and 21 made by the two switching circuits 16 and 22 are always contradictory and controlled so that reading and writing do not coincide.

The moving image detection signal read from the moving image detection signal storage device 20 or 21 is supplied to the moving image detection signal OR circuit 19,
Take a logical OR with the video detection signal from the video detection circuit 15,
The switching circuit 18 is controlled by the output of the moving image detection signal OR circuit 19.

Note that the input side control circuit 25 generates signals for controlling the synchronization separation circuit 2, the analog-to-digital converter 3, the input side buffer circuit 4, and the main memory control circuit 26.

The main memory control circuit 26 controls writing to and reading from the main memory devices 5, 6.7.

The output side control circuit 27 has main storage devices 5, 6 . Each circuit on the read side of γ and the main memory control circuit 26 are controlled.

Fig. 2 is a diagram showing the input television signal projected on the television screen, and the diagonal lines from a to b indicate that the television signal contains such bright diagonal information, and m is the line number of the first field, m
' indicates the line number of the second field, and its value is the same.

Currently, this television signal has 525 lines/frame and 60 fields/second (hereinafter referred to as "52576").
0 method".

), and this signal is a TSC television system with 625 lines/frame and 50 fields/second (hereinafter abbreviated as "J625150 system").

), it is only necessary to convert 525 lines of input into 625 lines, so the method of converting 5 lines of input into 6 lines is used, and when this conversion is performed, one of the conversion outputs is The section is shown in FIG.

In Fig. 3, n indicates the line number of the first field of the 625150 television signal, and m p m+1 p m+2 p m+3 indicated by a white circle in the figure is the line number m + of the first field of Fig. 2. m+1 pm
+2 line is output n y n + 1 s n +
It shows that the data is read out on two lines, and the output line numbers n + 5 and n + 6 show that the number of read lines is converted by continuing m + 5, but this part is indicated by a white circle. The distortion is within the diagonal lines.

Note that the diagonal line indicated by the white circle on the left side indicates the case where the diagonal line indicated by the white circle on the right side is delayed by one line.

Note that line numbers such as m' indicated by black circles indicate that the line indicated by line number m' in the second field in Fig. 2 is read out as the output line. Similarly, the black circle on the left is a signal delayed by one line from the signal indicated by the black circle on the right.

In this way, in order to correct the distortion caused by using one line twice in succession and obtain a smooth diagonal line as shown by the broken line in Figure 3, for example, on the n + 2 line of the output. By adding the lines of the m+1 white circle and m+2 white circle at a ratio of 1:3, it appears as if part of the diagonal line is located at the position of the X mark.

This is called line interpolation.

On the other hand, the position of the X mark can be obtained by adding the lines m'+2 and m+2 at a ratio of 3=1.

However, it is clear that the latter method reduces the vertical spread by half compared to the former method.

However, interpolation between lines m'+2 and m+2 is interpolation between different fields, so in the case of a video, if interpolation between these different fields is performed, the information on lines m'+2 and m+2 will be significantly different. Therefore, interpolation between different types of fields is not performed for moving images, but interpolation within the same type of fields is used for moving images, as shown in m+1 and m+2 shown above.

Interpolation between different fields is used for still images.

The moving image detection signal OR circuit 19 shown in FIG. 1 selects the interpolated signal for the moving image and the interpolated signal for the still image.

FIG. 4 shows how moving image detection is performed between fields of the same type separated by two fields.

Figure 4 shows that when squares with uniform brightness are moving in the order of A, B, C, and D on each field on a television screen, moving image detection is treated as a change in brightness, and If moving image detection is performed between fields containing information, the black level of the portion I is the same and no moving image detection signal is output, and the portion marked ■ also has uniform brightness, so moving image detection will not be performed.

Therefore, if conventional video detection is performed using only the D and B fields, and this video detection signal is used to switch interpolation between the video and still image parts, the interpolation of the ■ and field parts will be the still image interpolation. becomes.

In particular, when the I part is still image interpolation, line interpolation is performed between the D and C fields in the still image interpolation, so in addition to the D area, the I area is added to the interpolation output television screen. A bright portion of brightness will remain.

To prevent this, the TSC has a memory capacity of 4 fields, always reads the data of 4 fields, performs video detection between D and B and C and A, and uses the logical sum of these video detections to determine the video part and still image. If the image parts are separated, the part I between C and A will be determined to be a video, so highly accurate video detection will be performed, but it will require one extra field of storage compared to conventional devices. becomes.

On the other hand, since moving image detection is performed between C and A before one field in which moving image detection is performed between D and B, the moving image detection signal at this time is stored in the moving image detection signal storage device 20 or 21.

Video detection signal between D and B and the stored C and A
If the moving image portion and the still image portion are separated by the logical sum of the moving image detection signals in between, it is possible to detect a moving image with the same high accuracy as when using the four storage capacity fields.

Since this moving image detection signal may have an information content of 1 bit, the capacity of the moving image detection storage device 20, 21 for one field may be 1/8 of the capacity for storing one field of television signals.

In addition, if there is a moving image part on the television screen, even if the moving image part is interpolated to a range larger than that moving image part, a screen of sufficient quality can be obtained as a television screen, so all the moving image detection signals are memorized. If instead, one field is divided into blocks and a moving image detection signal is stored for each block, the capacity of the moving image detection signal storage devices 20 and 21 will be further reduced.

As is clear from the above explanation, the TSC is performed by storing the video detection signal over one field, reading out its contents in the next field, and separating the still image part and the video part by ORing with the video detection signal in this field.
It is possible to detect moving images with higher accuracy without increasing the capacity of the main memory of the device.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing an embodiment of a television standard format conversion device according to the present invention, FIG. 2 is a diagram showing a television screen of an input television signal of the television standard format conversion device, and FIG. A diagram of the television output signal after converting the number of lines; Figure 4 is a diagram in which the square screen moves for each field; Figure 5 is the operation of the input side buffer circuit and main memory device, and the output side buffer circuit. FIG. 6 is a time chart explaining the operation of the main memory. 1... Television signal input terminal, 2...
...Synchronization separation circuit, 3...Analog-to-digital converter. 4... Input side buffer circuit, 5, 6, 7...
... Main storage device, 8, 9, 10 ... Output side buffer circuit, 11 ... Switching circuit, 12, 13.
... Line interpolation circuit for moving pictures, 14... Line interpolation circuit for still images. 15... Video detection circuit, 16, 18, 22...
. . . Switching circuit, 17 . . . Field interpolation circuit, 19 . . . Video detection signal OR circuit, 20.
21... Video detection signal storage device, 23...
...Digital-analog converter, 24...Television signal output terminal, 25...Input side control circuit, 26...Main memory control circuit, 27...
...Output side control circuit, 28...Internal synchronization signal input terminal.

Claims (1)

[Claims] The image information is compared between fields of the same type separated by 12 fields, the still image part and the moving image part of the image are divided, line interpolation is performed using the information between the different fields for the still image part, and the same type field is used for the moving image part. In a television standard format conversion device that performs line interpolation using information in
A moving image detection signal storage device for storing over a field is provided on the reading side of the main storage device, means for reading out the stored moving image detection signal in a next field following the stored field, and means for reading out the stored moving image detection signal in a next field following the stored field; 1. A television standard format conversion device comprising means for calculating the logical sum of a moving image detection signal and a moving image detection signal of the next field.