JP2000244773A - Contour correcting device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To smooth and output the contour of video images even by a simple replacement processing. SOLUTION: Inputted video signals are delayed for one scanning each in delay circuits 1 and 2 and delayed for one dot in the delay circuits 3-8 and data for three lines of three dots per line are extracted. Then, whether or not nonlinear increase or decrease is present is judged for the respective lines in judgment circuits 9-11 and a judgment circuit 12 judges whether or not they are all the same. Also, a judgment circuit 13 judges whether or not increase or decrease is present among the three lines. A selector 19 performs output as a sampling dot under consideration as it is or decides and outputs one of dots at the same position in a horizontal direction on the lines in front and at the back or adjacent dots on the same line as a replacement pixel based on the judged results of the judgment circuits 12 and 13.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a contour correction device used for improving the sharpness of a video signal.

[0002]

2. Description of the Related Art A contour correction apparatus disclosed in Japanese Patent Application Laid-Open No. 6-46294 discriminates that data increases or decreases non-linearly at three consecutive points of a sampled video signal, and receives the discrimination result. And operates the central data of the three consecutive sampled points,
A replacement means for replacing and outputting the closest data of the preceding and following data is disclosed.

[0003] This apparatus will be described with reference to FIGS. 10 and 11. There are four patterns shown in FIGS. 10A to 10D in which three consecutive video data (referred to as luminance) S1, S2, and S3 in the horizontal direction increase or decrease in a non-linear manner.

That is, if S1 <S2 <S3, it is determined whether S2-S1 <S3-S2 holds or S2-S1>
Depending on whether S3-S2 is satisfied, two types of (1) and (2), S
If 1>S2> S3, S1-S2> S2-S3
Is satisfied or S1-S2 <S2-S3 (3),
There are two ways in (4), four in total.

The horizontal contour is emphasized only when the three consecutive data S1, S2, S3 increase or decrease linearly, and the central data S2 is compared with the preceding and succeeding data S1, S3, whichever is closer in value. This is done by replacing with the data of That is, regarding the increase pattern of FIG. 10, when the relationship of S2-S1 <S3-S2 is established for the difference data, the central data S2 is replaced with the preceding data S1,
If the relationship S2-S1> S3-S2 is established for the difference data, the central data S2 is replaced with the subsequent data S3. Regarding the decrease pattern of FIG. 10, when the relationship of S1-S2> S2-S3 is established for the difference data, the central data S2 is replaced by the following data S3, and the difference data is S1-S2 <S2-S3. When the following relationship is established, the central data S2 is replaced with the preceding data S1.

When the waveform shown in FIG. 11A is input to this contour correction device, the output is as shown in FIG. 11B, and the contour is corrected and output.

[0007]

However, in the above-mentioned conventional technique, when there is data at a position slightly changing from a straight line while changing substantially on a straight line as shown in FIG. If there is a diagonal edge on the screen as shown in FIG. 13 because it is replaced with a point, the eight data become the same value by four even though the original input signal gradually changes. There is a problem that the edge part is rattled (jaggy is conspicuous) due to conversion.

[0008]

SUMMARY OF THE INVENTION It is an object of the present invention to provide an outline correcting apparatus which can output a smoothed outline of an image even by a simple replacement process. Things.

In order to solve this problem, for example, the contour correction device of the present invention has the following configuration. That is, a contour correcting device for correcting a contour portion represented by a video signal, which receives a video signal sampled at a predetermined frequency as an input, and performs three consecutive samplings including a target sampling point and sampling points before and after the target sampling point. First determining means for determining whether the point data increases or decreases in a non-linear manner; and three consecutive sampling points one line before and one line after the three consecutive sampling points, respectively. A second determination unit that determines whether the sampling point increases or decreases in the same manner as three consecutive sampling points including the sampling point of interest; and three sampling points of the sampling point of interest, one line before and one line after the sampling point. Sampling point data increases monotonically or Includes a third determining means for determining that decreases monotonically, and a replacement means for replacing the data of the determination result received by attention sampling points of the first to third determination means,
The replacement means, when the second determination means determines that the data of three consecutive sampling points on each of the three lines similarly increases or decreases in a non-linear manner, According to the discrimination result, the noted sampling point, one line before and one line
The data at the three sampling points of the sampling point after the line monotonically increases or monotonically decreases, and one of the data at the sampling points one line before and one line after the sampling point of interest is determined before and after the sampling point of interest. If there is between the data of the sampling point closer to the target sampling point and the data of the target sampling point, select that point; otherwise, select the closer point of the preceding and following sampling points to select the target sampling point. And outputs the data.

According to a preferred embodiment of the present invention,
A video signal sampled at a predetermined frequency is input, and data of three consecutive sampling points including a sampling point of interest and sampling points before and after the same, and three consecutive sampling points one line before and one line after that In the case where each sampling point similarly increases or decreases in a non-linear manner, the data of the sampling point of interest is replaced with data closer to the preceding and following sampling points. At this time, the data at the three sampling points, that is, the sampling point of interest and the sampling points one line before and one line after that, are monotonically increasing or decreasing, and any one of the sampling points one line before or one line after. If the data is between the data of the sampling point to be replaced and the data of the sampling point of interest, the data of the sampling point of interest is replaced with the data of that point.

In this way, when correcting the contour of an oblique line, it is possible to correct the contour while avoiding that many of the same values are arranged in the vertical direction at the edge portion and preventing the oblique line from rattling.

[0012]

Embodiments of the present invention will be described below in detail with reference to the accompanying drawings.

[First Embodiment] FIG. 1 shows a block diagram of a contour correcting apparatus according to a first embodiment.

In the drawing, reference numerals 1 and 2 denote a delay circuit for delaying a video signal sampled at a predetermined frequency (each sampling point becomes one dot) for one line, and reference numerals 3 to 8 delay one dot. Delay circuit, 9-13
Is a decision circuit, 14 is a selector, 15 is a minimum value circuit, 16
Is a maximum value circuit, 17 is a maximum value circuit, 18 is a minimum value circuit,
19 is a selector. Hereinafter, the operation of the present embodiment will be described.

The input video signal is delayed one line at a time by a delay circuit 1 and a delay circuit 2, and further delayed by one sampling dot by delay circuits 3-8. As a result, the signals S1 to S9 are arranged as shown in FIG.

S1 to S3, S4 to S6, and S7 to S9 are input to the judgment circuit 10, the judgment circuit 9, and the judgment circuit 11, respectively. Note that the signal S2 is a target pixel, that is, a target sampling point.

The determination circuits 9 to 11 have the same configuration, and the configuration is as shown in FIG. 3 (here, the configuration of the determination circuit 10 for the pixel of interest).

In FIG. 1, reference numerals 20 and 21 denote adders, which perform calculations (subtraction) according to the reference numerals shown in the figure. 22, 2
3 is an absolute value circuit for obtaining the absolute value of the result calculated by the adders 20 and 21, 24 is a comparison circuit, 25 is a judgment table, and 26 is a sign judgment circuit.

In the adders 20 and 21, S
3-S2 and S1-S2 are calculated. These data are sent to the sign determination circuit 26, and S3-S2 is also sent to the absolute value circuit 22 and S1-S2 is also sent to the absolute value circuit 23. The sign judgment circuit 26 checks the signs of S3-S2 and S1-S2 and notifies the judgment table 25 of the state of both signs.

The absolute value circuit 22 and the absolute value circuit 23 take the absolute values of S3-S2 and S1-S2, respectively, and
Enter 4 | S3-S2 |, | S1
-S2 | is compared with the result, that is, information indicating whether the value of the target sampling point is closer to the value of the adjacent sampling point on the left or right.
Notify 6.

The determination table 25 is as shown in the table of FIG. 4, and the output is determined based on the inputs from the sign determination circuit 26 and the comparison circuit 24. That is, (1) of FIG.
A code indicating the pattern corresponding to (4)
In this embodiment, 1 to 4 are output, and “0” is output for other patterns.

Returning to FIG. 1, the judgment circuit 12
When the outputs have the same value, the values are output as they are, and when they are not the same, "0" is output. The output of the determination circuit 12 is defined as q.

The selector 14 selects and outputs one data from the inputs of S1, S2 and S3 based on the signal q from the determination circuit 12. The selection is performed as shown in the table of FIG. That is, (S1, S2, S3), (S4, S5, S
6) When three consecutive points on the three lines (S7, S8, S9) similarly increase or decrease in a non-linear manner, the data closer to S2 is selected and output from S1 and S3. At other times, the signal S2 of the target sampling point is output as it is.

On the other hand, the judgment circuit 13 has a configuration as shown in FIG.

In the figure, 27 and 28 are adders, and 29 is a sign judgment circuit. The adder 27 calculates S8-S2,
The adder 28 calculates S5−S2. The sign determination circuit checks the signs of these calculation results, and if they are different signs, and if the same sign or at least one of them is 0,
Outputs 0. That is, S8>S2> S5 or S8 <
If S2 <S5 is satisfied (the luminance increases or decreases in line order), “1” is output; otherwise, 0 is output.
The output of the determination circuit 13 is p.

Returning to FIG. 1, the minimum value circuit 14 and the maximum value circuit 15 output the smaller value and the larger value of S5 and S8, respectively. The output of the minimum value circuit 14 is input to the maximum value circuit 16 and is compared with the output t of the selector 14 and the larger one is output. The output of the maximum value circuit 15 is input to the minimum value circuit 17 and compared with the output t of the selector 14 and the smaller one is output.

The selector 18 outputs the output u of the maximum value circuit 16,
The output v of the minimum value circuit 17 and the output t of the selector 14 are input, and one of t, u, and s is selected and output according to the signal p from the determination circuit 13 and the signal q from the determination circuit 12.
FIG. 9 shows the operation of the selector 18 if it is understood or indicated by s.

The case where the value of the output p of the judgment circuit 13 is 0 will be described. In this case, the selector 19
Is output as it is. That is, (S1, S2,
S3), (S4, S5, S6), (S7, S8, S9)
If the three points on each of the three consecutive lines increase or decrease in a non-linear manner, the value of the sampling point S2 of interest is replaced with the closer value of S1 and S3.

Next, the operation of the selector 19 when the output p of the decision circuit 13 is 1 will be described in detail with reference to FIG.

When the value of the decision circuit q is 0, the selector 19
Outputs the output t of the selector 14 as it is. When q is 0, the output t of the selector 14 is S2.
The value of 2 is output without replacement.

When the value of the judgment circuit q is 1, the output u of the maximum value circuit is selected. At this time, the output t of the selector 14 is S
Since it is 1, the smaller value r of S6 and S8 and the larger value of S1 are output. S5, S
2. Since S8 is monotonically increasing or decreasing, the smaller value r of S6 and S8 is smaller than S2. S2 when q is 1
> S1, the larger value of r and S1 means that r is output if r is between S2 and S1,
If not, S1 is output.

When the value of the judgment circuit q is 2, the output v of the minimum value circuit is selected. At this time, the output t of the selector 14 is S
Since it is 3, the larger value s of S5 and S8 and the smaller value of S3 are output. S5, S
2. Since S8 is monotonically increasing or monotonically decreasing, the larger value s of S5 and S8 is larger than S2. When q is 2, S
Since 2 <S3, the smaller value of S1 and S3 means that if s exists between S2 and S3, s is output, and if not, S3 is output.

When the value of the decision circuit q is 3, the output u of the maximum value circuit is selected. At this time, the output t of the selector 14 is S
Since it is 3, the smaller value r of S5 and S8 and the larger value of S3 are output. S6, S
2. Since S8 is monotonically increasing or monotonically decreasing, the smaller value r of S5 and S8 is smaller than S2. When q is 3, S
Since 2> S3, r is output if r exists between S2 and S3, and S3 is output if r does not exist. When the value of the judgment circuit q is 4, the output v of the minimum value circuit is selected. At this time, since the output t of the selector 14 is S1, S5
The smaller value of S and S1 is output. Since S5, S2, and S8 are monotonically increasing or monotonically decreasing, the larger value s of S8 and S8 is larger than S2.

Since S2 <S1 when q is 4, s is output if S exists between S2 and S1, and S1 is output if S does not exist.

As described above, (S1, S2, S
3) Data of the sampling point S2 to be noted when three consecutive points on the three lines (S4, S6, S6) and (S7, S8, S9) similarly increase or decrease in a non-linear manner. Before and after sampling points S1, S
3 is replaced with the closer data. At this time, the data at the three sampling points, the sampling point S2 of interest, the sampling point S8 one line before and the sampling point S5 one line after it, monotonically increases or monotonically decreases. Is located between the data of the sampling point where the sampling point S2 of interest is to be replaced and the data of S2, the data of S2 is replaced with the data of that point.

In this manner, the vertical contour as shown in FIG. 8 is corrected in the same manner as in the prior art.
Further, as shown in FIG. 9, an oblique edge such as that shown in FIG. 13 is obtained. Can be.

In the embodiment, a 3 × 3 matrix has been described, but this is preferable for the embodiment. The reason for this is that if a larger size matrix is used, the sampling points to be replaced with the target sampling points will be separated from each other in terms of distance, and conversely, image quality will likely be degraded.

As described above, according to the present embodiment,
A video signal sampled at a predetermined frequency is input, and data of three consecutive sampling points including a sampling point of interest and sampling points before and after the same, and three consecutive sampling points one line before and one line after that In the case where all the sampling points similarly increase or decrease in a non-linear manner, the data of the sampling point of interest is replaced with the closer one of the preceding and following sampling points. At this time, the data at the three sampling points, that is, the sampling point of interest and the sampling points one line before and one line after that, are monotonically increasing or decreasing, and any one of the sampling points one line before or one line after. If the data is between the data of the sampling point to be replaced and the data of the sampling point to be replaced, the data of the sampling point to be replaced is replaced with the data of that point, thereby forming an oblique line. When the contour is corrected, it is possible to correct the contour while avoiding that many of the same values are arranged in the vertical direction at the edge portion and preventing the diagonal lines from rattling.

It should be noted that the contour correction device in the embodiment may be incorporated in a display device, for example, or may be incorporated in a single device separate from the display device or in an external device.

[0040]

As described above, according to the present invention, it is possible to output an image with smooth outlines even by a simple replacement process.

[Brief description of the drawings]

FIG. 1 is a block diagram of an embodiment of the present invention.

FIG. 2 is a diagram showing an arrangement of sampling points in the embodiment.

FIG. 3 is a block diagram of a determination circuit 10 in FIG. 1;

4 is a diagram showing a relationship between an input and an output of a determination circuit 10 in FIG.

FIG. 5 is a diagram showing a relationship between an input and an output of a selector 14 in FIG. 1;

FIG. 6 is a block diagram of a determination circuit 13 in FIG. 1;

FIG. 7 is a diagram showing an input / output relationship of a selector 19 in FIG. 1;

FIG. 8 is a signal waveform diagram for explaining the operation of the embodiment.

FIG. 9 is a signal waveform diagram for explaining the operation of the embodiment.

FIG. 10 is a signal waveform diagram for explaining a conventional operation.

FIG. 11 is a signal waveform diagram for explaining a conventional operation.

FIG. 12 is a diagram showing a conventional problem.

FIG. 13 is a diagram showing a conventional problem.

 ────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yukio Masuda 3-30-2 Shimomaruko, Ota-ku, Tokyo F-term in Canon Inc. (reference) 5C021 PA53 PA56 PA62 PA83 RA02 SA22 SA25 XB03 XB07

Claims (2)

[Claims] 1. A contour correcting device for correcting a contour portion represented by a video signal, comprising a video signal sampled at a predetermined frequency as input, and three sampling points including a sampling point of interest and sampling points before and after it. First determining means for determining whether data at consecutive sampling points increases or decreases in a non-linear manner; and three consecutive samplings one line before and one line after the three consecutive sampling points Second determining means for determining whether the point increases or decreases in the same manner as three consecutive sampling points including the noted sampling point; and the noted sampling point and sampling points one line before and one line after the noted sampling point Data at three sampling points increase monotonically A third discriminating unit for discriminating that the addition or the monotonous decrease is performed, and a replacing unit for replacing data of the sampling point of interest in response to the discrimination result of the first to third discriminating units, When it is determined that the data of three consecutive sampling points on each of the three lines similarly increases or decreases in a non-linear manner by the second determination means, the target value is determined based on the determination result of the third determination means. The data at the three sampling points of the sampling point to be processed and the sampling points one line before and one line after it monotonically increases or decreases, and any one of the data at the sampling points one line before and one line after the target sampling point Is the target of the sampling points before and after the target sampling point. If there is between the data closer to the sampling point and the data of the sampling point of interest, then select that point; otherwise, select the closer point of the preceding and following sampling points and replace the data of the sampling point of interest and output A contour correcting device. 2. A contour correction device for inputting a video signal and outputting a video signal in which a contour portion represented by the video signal is corrected, comprising three consecutive pixels of a pixel of interest on a horizontal scanning line and two adjacent pixels before and after the pixel of interest. Whether the luminance distribution of the pixel increases or decreases in a non-linear manner, and whether the luminance distribution of each of the three pixels on the two lines before and after the line of the pixel of interest is non-linear Discriminating means for discriminating whether or not all three lines are non-linearly increasing or decreasing. If the first discriminating means determines that all three lines increase or decrease in a non-linear manner, If it is determined that an adjacent pixel close to the luminance of the target pixel is other than that, first selection means for selecting the pixel of interest as a first replacement candidate pixel; A second determining means for determining whether the luminance distribution of the pixel is increasing or decreasing; and a second determining means for determining whether the luminance distribution of the pixel is larger or smaller on a preceding or succeeding adjacent line and the first replacement candidate pixel selected by the first selecting means. And a second selecting means for selecting a smaller one as a second replacement candidate pixel between the first and second replacement candidate pixels selected by the first selecting means. A second selecting means for selecting a larger one as a third replacement candidate pixel, and an increase in luminance between three lines by the second discriminating means;
If it is determined that the brightness is not any of the reductions, the first replacement candidate pixel is selected. If the brightness between the three lines is in either the increase or decrease state by the second determination means, the first replacement candidate pixel is selected. A contour correction device comprising: a replacement pixel selection unit that selects and outputs one of the second and third replacement candidate pixels.