JP3216271B2 - Scan converter - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a scanning converter for converting a scanning standard of an input signal into a different scanning standard and outputting the same.
The present invention relates to a conversion device .

[0002]

2. Description of the Related Art In recent years, various video media have appeared, and in addition to television signals, video signals of various scanning standards such as personal computers and workstations have been used. In addition, there is an increasing need for a scan conversion device for displaying images on a display device of a single scanning standard. This scan converter converts the horizontal frequency or vertical frequency of an input video signal into
This is a device for converting to a different horizontal or vertical frequency. Here, when converting the vertical frequency,
That is, a case where the number of scanning lines is converted will be described as an example.

In the conversion of the number of scanning lines, a method of obtaining video signal data matching the scanning line position of an output video signal by interpolation based on an input video signal is generally used. Conventionally, a method called linear interpolation has been used. Here, a scan conversion apparatus using this linear interpolation will be described as a conventional example.

[0004] A conventional scan conversion apparatus will be described below with reference to FIGS. FIG. 5 is a block diagram of a conventional scan conversion device, and FIG. 6 is a waveform diagram showing the operation of the conventional scan conversion method. Reference numeral 1 denotes an input video signal, which is a binary video signal of a background color and a character color. 2 and 3 are delay circuit units. Here, for the sake of explanation, delay circuit units 2 and 3
Are delay circuits for delaying the video signal by one scanning line, and are line memories having a storage function. 4 is a video signal delayed by one scanning line with respect to the input signal 1, and 6 is a video signal further delayed by one scanning line. 7, a control unit for controlling the delay circuit units 2, 3, and 5 a control signal.
8 is a subtraction unit for subtracting the data 6 from the delayed data 4;
9 is the data after the subtraction, and 15 is the interpolation position information indicating the position of the scanning line to be interpolated. 10 is a multiplication unit that multiplies the data 9 after the subtraction by the interpolation position information 15, 11 is the data after the multiplication, 12 is an addition unit that adds the data 11 after the multiplication and the data 6 after the delay, 35 is a threshold value, 36 is a level comparison unit for comparing the threshold value with the output of the addition unit 12, and 40 is a binary output video signal obtained as a result.

[0005] The operation of the scanning conversion apparatus configured as described above will be described below. Input video signal 1
Is delayed by one scanning line by the delay circuit unit 2. The delayed data 4 is further delayed by one scanning line by the delay circuit unit 3 to become delayed data 6. The reason why two delay circuits are provided is that when two or more interpolated scanning lines are obtained between the original scanning lines, it is necessary to use the original video signal data twice or more, and this is controlled. This is the control unit 7 and the control signal 5.

When the original video signal data is used twice or more, the control unit 7 generates a control signal 5 to the delay circuit units 2 and 3 so as to stop updating by rewriting data. The subtraction unit 8 subtracts the data 4 and the data 6 having a delay difference of one scanning line from the data 4 to obtain difference data 9. The multiplication unit 10 multiplies the difference data 9 by the interpolation position information 15 to obtain multiplication data 11. The interpolation position information 15 is information indicating a scanning line position of the output video signal 40 with respect to each scanning line of the original input video signal 1, that is, a position of a scanning line to be newly created by interpolation.

[0007] The delayed data 6 is added to the multiplied data 11 in an adder 12, and the result of the addition is compared with a threshold 35 in a level comparator 36 to obtain a result output video signal 40. The above operation will be described in more detail with reference to FIG.

FIG. 6A shows the luminance level of each scanning line of the input video signal 1, and reference numeral 41 denotes an interpolation line for interpolation. 21a is a time interval of each scanning line of the input video signal 1. FIG. 6B shows an output signal of the adder 12, FIG. 6C shows a luminance level of each scanning line of the output video signal 40, and 22a shows a time interval of each scanning line. Is shown. FIG. 6 shows a case where the number of scanning lines is enlarged 1.8 times. The interpolation position information 15 in FIG. 5 indicates that the output signal scanning line position 2 with respect to the input signal scanning line interval 21 a
2a, and the ratio of the output signal scanning line position 22b to the input signal scanning line interval 21b when obtaining the interpolation scanning line 42. However, in this case,
21a and 22b are equal, but 22a and 22b are not necessarily equal.

Therefore, the interpolation position information 15 has a value ranging from 0 to 1. From these, the interpolation position information 15
Multiplying the difference data 9 by the multiplication unit 10 and adding the obtained multiplication data 11 to the delay data 6 by the addition unit 12, ie, by setting the interpolation line 41 to the luminance level of each scanning line of the input video signal 1. Is connected by a straight line,
For this reason, it is called linear interpolation.

As a result of the linear interpolation, the interpolated scanning lines 42,
43 is obtained, and thereafter, the same processing is performed for each scanning line, and the output of the adder 12 becomes a signal as shown in FIG. The output of the adder 12 is output to the level comparator 36.
When the output signal level of the adder 12 is lower than the level of the threshold 35 as compared with the threshold 35, the level of the adder 12 becomes equal to the level of the background color of the input 1 When the output signal level of Twelve is higher or equal, the binary output video signal 40 is obtained by converting it to a level equal to the character color of input 1. In the case of FIG.
The threshold value 35 is set to a level almost close to the character color level.

[0011]

However, in the above configuration, especially when a video signal of a computer is scan-converted, it is represented at a binary level, for example, a black background color and a white character like character information. On the screen, after the interpolation, that is, the output signal of the adding unit 12 is not always at the same level as the character color of the input 1, and therefore, depending on the threshold level, as shown in FIG. Had a problem of being missing.

In view of the above problems, the present invention provides a scanning line conversion apparatus that does not cause data loss due to interpolation processing, and further provides a scanning conversion apparatus that improves the quality of an output video according to the output data interval. Things.

[0013]

According to the present invention, there is provided a scan conversion apparatus including a multiplication coefficient generation section and a comparison section for interpolation position information. In addition, output data
In order to obtain an optimum image quality according to the data interval, an area comparison data generator or a threshold controller is provided.

[0014]

According to the present invention, the image quality at the time of scan conversion can be improved by realizing not the linear interpolation but the polygonal line interpolation by the above-described configuration, and the optimum image quality can be obtained according to the output data interval. be able to. Furthermore, by setting the threshold value arbitrarily, an output video signal of an appropriate binary level can be obtained.

[0015]

【Example】

(Embodiment 1) A scan conversion apparatus according to an embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram showing an embodiment, and FIG.
FIG. 3 is a waveform diagram showing a broken line interpolation operation realized by the configuration of FIG. Reference numeral 31 denotes output data interval information, 19 denotes a comparison unit for comparing the output data interval information 31 with the interpolation position information 15, 17 denotes an area signal indicating which area the interpolation position is in, 16 denotes the area signal 17 and the interpolation signal Location information 15
A multiplication coefficient generation unit 14 for obtaining a coefficient from and is coefficient data for the multiplication unit 10. 20 is an output video signal.

FIG. 2A shows an input video signal 1
Indicates the luminance level of each scanning line. Reference numeral 24 denotes an interpolation line at the time of interpolation. As shown in the figure, a polygonal line connects each luminance level of the input scanning line. Reference numeral 21 denotes a time interval between each scanning line of the input video signal 1. FIG. 2B shows an output signal of the adding unit 12 obtained using the interpolation line 24. FIG. 2C shows an output obtained as a result of comparing the output of the adder 12 with the threshold 35 in the level comparator 36 when the level of the threshold 35 is made equal to the character color of the input 1. 3 shows a luminance level of each scanning line of the video signal 20. FIG. 2 shows a case where the number of scanning lines is enlarged 1.8 times.

Reference numerals 23a and 23b denote each area when the time interval 21 of the input scanning line is divided into two areas. The width of the region 23a is equal to the data output interval 31.

The operation of the scanning conversion device configured as described above will be described below. By comparing the interpolation position information 15 and the data output interval 31 with the comparison unit 19, it is determined whether the interpolation scanning line 20a falls into one of the regions 23a and 23b, and a signal 17 indicating the region is obtained. In this example, the area 23a is entered. In the multiplication coefficient generator 16, the interpolation scanning line 20 a is converted into the area 23 a by the area signal 17.
If it is in the area 23b, the coefficient 14 is output as 0, and if it is in the area 23b, the coefficient is obtained from the interpolation position information 15 in the same manner as in linear interpolation, and the coefficient 14 is output. I do. In this example, since the interpolation scanning line 20a enters the area 23a, the coefficient 14 outputs a value of 0. Interpolated scanning lines are similarly obtained for the subsequent scanning lines. Further, when the level of the threshold 35 is selected to be the same as the level of the character color of the input 1, as a result of comparison in the level comparing section 36, FIG.
A binary output video signal 20 shown in the lower part of FIG.

As described above, according to the present embodiment, by providing the multiplication coefficient generation unit and the comparison unit of the interpolation position data, the output video signal 20 has a scanning level equal to the luminance level of each scanning line of input 1. Since one line can always be obtained, no loss of data due to the interpolation process occurs regardless of the threshold value set.

Embodiment 2 Next, a scan conversion apparatus according to another embodiment of the present invention will be described with reference to the drawings.

FIG. 3 is a block diagram of the scan conversion device .
FIG. 4 is a waveform diagram showing the operation of broken line interpolation realized by the configuration of FIG. In FIG. 3, reference numeral 18 denotes area comparison data, and 30 denotes area comparison data 1 corresponding to an output data interval.
8 is an area comparison data generation unit that generates the data No. 8. In FIG. 4, (a) shows the luminance level of each scanning line of the input video signal 1. Numeral 34 denotes an interpolation line for complementation. As shown in FIG. Tied. The area 23a has a width twice as large as the output data interval 31.

FIG. 4B shows an output signal of the adder 12 when the interpolation processing is performed using the interpolation line 34. FIG. 4C shows the output 20 when the level of the threshold 35 is equal to the level of the character color of the input 1. FIG. 4
Shows the case where the number of scanning lines is increased 3.6 times.

The operation of the scanning conversion device configured as described above will be described below. The area comparison data generator 30 changes the width of the area 23a according to the output data 31. In the present embodiment, the area 23a indicates a double that is set to twice the output data interval 31. In this case, the output signal of the adder 12 obtained as a result of the interpolation, that is, FIG.
The signals shown in the middle row always include two interpolated scanning lines equal to the level of each original input 1 scanning line. The output 20 obtained as a result of comparing the output of the adder 12 with a threshold 35 equal to the level of the original input 1 character color includes:
Naturally, two or more scanning lines of the same level as the scanning line of the character color level of the input 1 are included.

As described above, according to the present embodiment, by providing the area comparison data generating section, the area comparison data corresponding to the output data interval is generated, and as a result, the input signal has the same level as each scanning line. A plurality of scanning lines after interpolation can be obtained, so that not only data is not lost due to the interpolation process in the output, but also control can be performed to obtain an optimum image quality with respect to the output data interval.

Further, by providing the threshold value control section 32, the level of the threshold value 35 can be set to any value between the background color and the character color, so that the output video image quality can be changed to a desired appearance. Can be set.

[0027]

As described above, according to the scan conversion apparatus of the present invention, the multiplication coefficient generation section and the comparison section of the interpolation position data are provided, so that the polygonal line interpolation is realized and the interpolation processing at the time of scan conversion is performed. Data can be eliminated.

Further, according to the scan conversion apparatus of the present invention, by providing the area comparison data generation section for changing the area comparison data to the comparison section according to the output data interval, the same level as each scanning line of the input signal is provided. It is possible to obtain a plurality of scanning lines after the interpolation, not only to prevent data loss due to the interpolation processing in the output, but also to obtain an optimum image quality according to the output data interval.

Since the threshold level can be set to any value between the background color and the character color by providing the threshold control unit, the output image quality can be set to a desired appearance. Becomes possible.

[Brief description of the drawings]

FIG. 1 is a block diagram of a scan conversion device according to an embodiment of the present invention.

2A is a waveform diagram illustrating the operation of the scan conversion device according to one embodiment of the present invention; FIG. 2B is a waveform diagram illustrating the operation of the scan conversion device according to one embodiment of the present invention; FIG. 3 is a waveform diagram illustrating the operation of the scan conversion device according to one embodiment.

FIG. 3 is a block diagram of a scan conversion device according to another embodiment of the present invention.

[4] (a) a waveform diagram illustrating the operation of the scan conversion apparatus in an embodiment of the waveform (b) the present invention described scan conversion apparatus <br/> operation in an embodiment of the present invention (c FIG. 4 is a waveform chart for explaining the operation of the scan conversion apparatus according to one embodiment of the present invention.

FIG. 5 is a block diagram of a conventional scan conversion device.

FIG. 6 is a waveform diagram illustrating the operation of a conventional scan conversion device.

[Explanation of symbols]

 2, 3 delay circuit section 8 subtraction section 10 multiplication section 12 addition section 16 multiplication coefficient generation section 36 level comparison section 19 comparison section 30 area comparison data generation section 32 threshold value control section

Claims (3)

(57) [Claims] An input video signal corresponding to one scanning line or two scanning lines;
A delay circuit portion of the video signal to scanning line delay, between the accessory and the subtraction unit for calculating a difference of the video signal before and after the delay, a multiplication unit for multiplying the coefficient to the difference, between the scanning lines and the scanning lines of the video signal From the interpolation position information indicating the position to output the scanning line and the output data interval indicating the interval between each scanning line in the final output after interpolation, the interpolation scanning line is located between the scanning line of the video signal and the scanning line. An area with an interval longer than the output data interval
A comparison unit that determines which of the two types of regions is included in the remaining region and outputs a region signal indicating the result, and disconnects the output of the comparison unit and the output of the interpolation position information from the comparison unit.
Linear interpolation when two areas are separated and belong to the first half
Signal that does not perform
A multiplication coefficient generation unit for calculating an interpolated coefficient; and adding the delayed video signal to the multiplied video signal.
And an interpolation unit that outputs an interpolation result with a luminance equal to or higher than a certain level in the input video signal.
And a level comparator for comparing an output level of the adder with a threshold level to determine an output video signal level. 2. The image quality after interpolation processing can be adjusted as desired.
The cut in accordance with the output data interval to the ability
2. The scanning conversion apparatus according to claim 1, further comprising an area comparison data generating section for arbitrarily setting the widths of the two areas and inputting them to the comparison section as area comparison data. 3. The scanning conversion apparatus according to claim 1, further comprising a threshold control section for arbitrarily setting a threshold level.