JP2003022064A - Horizontal line correcting method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a horizontal line correcting method which can emphasize the edges of horizontal lines in a sequentially-scanned image obtained by sequentially scanning and converting an interlaced scanned image or an enlarged/ reduced image obtained through scaling processing and reduce aliasing crawling disturbance. SOLUTION: The horizontal line correcting method which corrects luminance values in horizontal lines in a processed image obtain from the original image through sequential scanning conversion or scaling processing comprises a 1st step for detecting a horizontal line in the processed image, a 2nd step for obtaining the maximum luminance level in the horizontal line from circumferential fields of the original image, and a 3rd step for correcting the luminance level in the vertical-width center of the horizontal line so that it closes up the maximum luminance level obtained in the 2nd step.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a horizontal line for correcting the brightness value of a horizontal line in a progressive scan image obtained by progressively converting an interlaced scan image or in a scaled image obtained by scaling processing. Regarding the correction method.

[0002]

2. Description of the Related Art Conventionally, as a typical method of generating an interpolation line when converting interlaced scanning to progressive scanning,
There are inter-field interpolation and intra-field interpolation.

Inter-field interpolation refers to the current field and 1
This is a method of simply performing interpolation between the preceding field and an interpolation line. What is intra-field interpolation?
This is a method of generating an interpolation line by performing inter-line interpolation or diagonal correlation in the current field.

Generally, when the image is a still image or when the image is a moving image but the motion is small, inter-field interpolation is adopted, and when the image is a moving image and the motion is large. In-field interpolation is adopted.

When the image is a moving image, motion compensation interpolation may be used in which the pixel value of the interpolation line is obtained from the past field based on the detected motion vector.

The problems of the conventional method will be described below with reference to FIGS.

FIG. 10 shows an original image. 11 shows an example of inter-field interpolation, FIG. 12 shows an example of inter-line interpolation (intra-field interpolation), and FIG. 13 shows an example of motion compensation interpolation.

In the original image, 0.75 [lin] is vertically downward.
It includes a horizontal white line created in CG that moves in e / field]. FIG. 10 shows the luminance levels of a part of the horizontal white line (x coordinate is fixed) over three fields. Here, the horizontal white line is one of the horizontal lines.
A line in which the brightness of a horizontal line is relatively higher than the brightness of its peripheral portion.

10 to 13, t represents time, a solid line represents a scanning line in the Odd field, a broken line represents a scanning line in the Even field, and a square represents a moving horizontal white line. Also, the numbers in FIGS. 11 to 13 represent the luminance values of pixels on the reference line, and the luminance values circled are the luminance values of the actual pixels (even field at times t-1 and t + 1, and at time t). Odd field), and the luminance value not circled represents the luminance value obtained by scanning line interpolation.

In inter-field interpolation (FIG. 11), time t
However, at time t + 1, the vertical width of the horizontal white line becomes thicker and the maximum brightness level of the horizontal white line decreases.

In the interline interpolation (FIG. 12), the vertical width of the horizontal white line is always thick. Also, the maximum brightness level of the horizontal white line varies depending on the field.

In the motion-compensated interpolation (FIG. 13), the selected interpolation pixel value is different and cannot be said to be the case at once. However, due to the accuracy of the motion vector, a phenomenon that appears in the inter-field interpolation or the inter-line interpolation occurs.

If the above-mentioned state occurs continuously, the lines in the image will flicker. That is, the vertical width of the horizontal white line becomes thicker or thinner at a certain cycle, and the maximum brightness of the horizontal white line becomes higher or lower. Although such a phenomenon is caused by aliasing, it more simply represents a phenomenon that a blurred horizontal line crawls, and is therefore referred to as aliasing and crawling interference in this specification.

In this example, the horizontal white line created by CG has been described as an example. However, in the image photographed by the CCD camera, the factor due to the structure of the camera is further added, and the vertical width of the horizontal white line becomes thicker. Become.

[0015]

SUMMARY OF THE INVENTION The present invention is capable of emphasizing the edges of horizontal lines in a progressive scan image obtained by progressively converting an interlaced scan image or in a scaled image obtained by a scaling process. It is an object of the present invention to provide a horizontal line correction method capable of reducing aliasing / crawling interference.

[0016]

According to a first aspect of the present invention, a horizontal line for correcting a luminance value in a horizontal line in a processed image obtained by subjecting an original image to sequential scanning conversion processing or scaling processing. In the correction method, a first step of detecting a horizontal line in the processed image, a second step of obtaining a maximum brightness level in the horizontal line from an original image of a peripheral field, and a brightness level in a vertical center of the horizontal line are set. , And a third step of performing correction so as to approach the maximum brightness level obtained in the second step.

According to a second aspect of the present invention, in the horizontal line correcting method according to the first aspect, when the luminance level at the center of the vertical width of the horizontal line is corrected by the third step, the center of gravity of the horizontal line and the total luminance do not change. As described above, the method is characterized by including the fourth step of correcting the luminance level of the other portion in the horizontal line.

[0018]

DETAILED DESCRIPTION OF THE INVENTION

[1] Description of Configuration of Scan Conversion Circuit

FIG. 1 shows the configuration of the scan conversion circuit.

In this scan conversion circuit, a circuit for correcting a horizontal white line is added after the conventional scan conversion circuit that adaptively switches between inter-field interpolation and intra-field interpolation depending on the degree of motion. The RY and BY signal components, which are the other components of the video signal, are not shown for convenience of explanation, but it is assumed that they do not conflict with the phase of the Y signal at the time of output.

The 2: 1 interlaced scan image signal (input image signal) is sent to the motion vector detection circuit 1, the first field memory 2, the inter-field interpolation section 3 and the intra-field interpolation section 4.

The data stored in the first field memory 2 (data one field before) is sent to the inter-field interpolating unit 3, the second field memory 5 and the horizontal line correction circuit 7.

The data stored in the second field memory 5 (data two fields before) is sent to the motion vector detection circuit 1 and the horizontal line correction circuit 7.

The motion vector detection circuit 1 detects a motion vector between both fields based on the data of the current field and the data two fields before from the second field memory 5. From the motion vector detection circuit 1 to the mixing circuit 6, a signal indicating the presence or absence of motion and the degree of motion is sent. From the motion vector detection circuit 1 to the horizontal line correction circuit 7, the horizontal direction vector Vx and the vertical direction vector Vy indicating the amount of movement from the current field to the field two fields before are displayed.
And are sent.

The inter-field interpolation unit 3 performs inter-field interpolation processing based on the data of the current field and the data of the previous field from the first field memory 2. The output of the inter-field interpolation unit 3 (inter-field interpolated progressive scan signal) is sent to the mixing circuit 6.

The intra-field interpolation unit 4 performs intra-field interpolation processing based on the data of the current field. The output of the intra-field interpolator 4 (inter-field interpolated progressive scan signal) is sent to the mixing circuit 6. The mixing circuit 6 weights and adds the inter-field interpolated progressive scan signal and the inter-field interpolated progressive scan signal, for example, according to the degree of motion sent from the motion vector detection circuit 1. On this occasion,
The greater the degree of motion, the greater the weight value of the inter-field interpolated progressive scan signal.

The adaptive progressive scan image signal output from the mixing circuit 6 is sent to the horizontal line correction circuit 7.

The horizontal line correction circuit 7 detects a horizontal white line in the adaptive progressive scan image, and concentrates the brightness at the upper and lower central positions of the horizontal white line while maintaining the total brightness and the center of gravity of the detected horizontal white line. So that the brightness in the horizontal white line is corrected.

[2] Description of Configuration of Horizontal Line Correction Circuit 7

FIG. 2 shows the configuration of the horizontal line correction circuit 7.

[2-1] Line memory unit 11

The adaptive progressive scan image signal output from the mixing circuit 6 is input to the line memory unit 11. As shown in FIG. 3, the line memory unit 11 has a structure in which a plurality of 1H line memories are connected in a ring buffer shape.

Of all the areas in the line memory unit 11, a search area is an area (a line memory group not hatched in FIG. 3) excluding the line memory in which the adaptive sequential scanning image signal is being input from the mixing circuit 6. I will decide. As will be described later, in the search area, the horizontal line detection circuit 13 searches for a horizontal white line, and the brightness value in the searched horizontal white line is written by the line drawing circuit 15.

For the pixels for which the correction values have already been written by the line drawing circuit 15, the horizontal line detection circuit 1
As shown in FIG. 3, each pixel value storage area in the line memory unit 11 is composed of a luminance data unit and a 1-bit drawing completion determination flag unit so that the same processing is not performed again by the third unit. The drawn determination flag is set when the adaptive sequential scanning image signal output from the mixing circuit 6 is written.
It becomes "0" and becomes "1" when the correction value is written from the line memory drawing circuit 15.

[2-2] Horizontal line detection circuit 13

The horizontal line detection circuit 13 combines a plurality of general filters for detecting horizontal white lines in an image, such as a Prewitz filter, and as shown in FIG. While scanning to
A horizontal white line with a high brightness level included in the search area is detected.

That is, upper and lower lines (for example, Lev [1] and Le
v [2] line) and one skipped upper and lower lines (eg
From the relationship between the Lev [1] and Lev [3] lines), pixels with a higher brightness level than the surrounding pixels are extracted. Horizontal line detection circuit 13
Then, only when the vertical width of the detected pixel set is 4 lines or less, the detected pixel set is regarded as a horizontal white line.

That is, when a white line having a width of 4 lines or less is detected from a state where a white line having a vertical width of 4 lines or less is not detected, it is considered that the left end (start point) of the horizontal white line has been detected, and the horizontal white line is detected. The right end (end) of the horizontal white line is searched for in the right direction of the start point. Then, it is assumed that the end of the horizontal white line is detected when the white line being searched for is interrupted. If a white line whose vertical width exceeds 4 lines is detected during scanning after finding the left end of the white line, or if the detected vertical width of the white lines exceeds 4 lines in total, It is regarded as an oblique line, and the line end scanning is stopped.

FIG. 5A shows the case where the vertical width of the set of detected pixels having high luminance is 4 lines or less.
(B) shows a case where the vertical width of a set of detected high-intensity pixels exceeds 4 lines in total.

After detecting the end of the horizontal line, the horizontal line detection circuit 13 detects the starting point coordinates (indicated by 1 in FIGS. 4 and 5A) and the ending point coordinates (FIGS. 4 and 5) of the detected horizontal white line.
(Indicated by 2 in (a)) is sent to the line luminance calculation circuit 14.

In the horizontal line detection circuit 13, the x coordinate (starting point x coordinate) defined at the left end of the detected horizontal white line is changed to the x coordinate (end point x coordinate) defined at the right end of the horizontal white line. Between the scanning lines in the search area of the line memory unit 11, the luminance sum for each scanning line is calculated, and the luminance sum for each scanning line is then added to the number of luminances in one scanning line (end point x coordinate). -Starting point x coordinate +
Average brightness level l for each scan line by dividing by 1)
Find ev. Then, the calculated average luminance level lev for each scanning line is sent to the line luminance calculation circuit 14.

Further, the horizontal line detection circuit 13 sends the detection end signal of the horizontal line end and the coordinate information (line search information) of the detected horizontal white line to the line maximum brightness detection circuit 12. Note that this coordinate information is absolute coordinates (coordinates of the adaptive progressive scan conversion image) for both x and y coordinates.

[2-3] Line maximum brightness detection circuit 12

The line maximum brightness detection circuit 12 determines the brightness level of the upper and lower center of the horizontal white line detected by the horizontal line detection circuit 13. Here, the vertical center of the horizontal white line refers to the central scanning line of the scanning lines forming the horizontal white line.

The line maximum luminance detection circuit 12 first uses the motion vectors Vx and Vy obtained two fields before with the current field as a reference, and the detected horizontal white line is 1
It is calculated which of the part before the field and the part before the two fields corresponds to. Then, the corresponding portion is scanned to detect the highest luminance value (hereinafter referred to as the maximum line luminance) among the luminance values in the portion corresponding to the horizontal white line. Note that this maximum brightness value is assumed to be sufficiently smoothed in the horizontal direction so that a noise component like spike noise is not mistakenly recognized as the maximum brightness.

The line maximum brightness Vmax thus obtained is sent to the line brightness calculation circuit 14.

Further, in the line maximum brightness detection circuit 12,
Motion vector value V used when obtaining the maximum line brightness
The presence or absence of movement of the horizontal white line detected by the horizontal line detection circuit 13 is confirmed by x and Vy. | Vx | + | Vy
If | is greater than or equal to a predetermined value, it is determined that there is movement, and the fact is notified to the line drawing circuit 15.

[2-4] Line luminance calculation circuit 14

The line luminance calculation circuit 14 receives the average luminance level lev for each scanning line from the horizontal line detection circuit 13.
After receiving [i] and a signal indicating that a horizontal white line has been detected, the following series of processing is performed. The line brightness calculation circuit 14 does nothing if the horizontal line detection circuit 13 does not detect a horizontal white line.

In the line luminance calculation circuit 14, the average luminance level l for each scanning line obtained from the horizontal line detection circuit 13
From ev [i] and the line maximum brightness Vmax obtained from the line maximum brightness detection circuit 12, one scan line at the upper and lower central portions of the horizontal white line detected by the horizontal line detection circuit 13 is close to the horizontal line maximum brightness Vmax. And the brightness value in the horizontal white line is changed so that the center of gravity and the total brightness of the horizontal white line do not change.

FIG. 6 shows the overall processing procedure by the line luminance calculation circuit 14.

The line brightness calculation circuit 14 generates a work array pattern, performs a selection process (step 1), a compensation process for the upper and lower center brightness levels of horizontal white lines (step 2), a centering process for the brightness levels (step 3), and An instruction (step 4) is given to the line drawing circuit.

(1) Step 1: Work array pattern generation and selection processing

Two kinds of work array patterns used to change the average luminance value of each scanning line within the detected horizontal white line are created. The average brightness level L for each scanning line from the y coordinate that is one less than the starting y coordinate to the ending y coordinate
Generating a first work array pattern having ev as an element and a second work array pattern having an average brightness level Lev for each scanning line from the start y coordinate to the y coordinate that is one greater than the end y coordinate as an element To do.

As in the example shown in FIG. 4, if the starting point y-coordinate of the detected horizontal white line is "2" and the ending point y-coordinate is "5", the first work arrangement pattern becomes the pattern A of FIG. , The second work array pattern is pattern B in FIG.

Of the two work arrangement patterns, one having a luminance centroid close to 3 is selected. The total brightness S, the moment M, and the center of gravity G are obtained by the following equation (1).

[0058]

[Equation 1]

In the above equation (1), N is the number of elements (= 5) in the work array pattern. Li represents each element (average brightness value). The subscript i represents the coordinates (relative y-coordinates) of the elements of the work array pattern, where element 1 is 1, element 2 is 2 ,. ． ． , Element 5 is 5.

In FIG. 7, lev [1], lev
[2], lev [3], lev [4], lev [5],
The values of lev [6] are 97, 121, 140, and
Assuming 144, 118 and 90, the center of gravity of pattern A is 3.1 and the center of gravity of pattern B is 2.6. Therefore, the pattern A whose center of gravity is close to 3 is selected.

(2) Step 2: Compensation process for upper and lower central luminance levels of horizontal white line

In step 2, the brightness at the vertical center position (center of gravity position) of the horizontal white line whose brightness level value has decreased is obtained by the line maximum brightness V obtained from the line maximum brightness detection circuit 12.
Perform processing to approach max. At this time, processing is performed so that the total brightness and the center of gravity of the work array pattern do not change.

FIG. 8 shows the case where the pattern A is selected.
The processing procedure of step 2 is shown.

Before explaining each step of FIG.
The concept of the process of step 2 will be described.

When the brightness L [3] at the center of gravity is smaller than the maximum line brightness Vmax, the brightness level 3V to be added to L [3] is determined. In order not to change the total luminance and the center of gravity (moment) when 3V is added to L [3], 2V is subtracted from L [2] and L [5] is set.
It is necessary to subtract 1V from L, or 1V from L [1] and 2V from L [4].

At this time, in order to ensure that the lowest luminance in the work arrangement pattern does not change, the element (L [5] or L [1]) minus 1V is the element having the lowest luminance. You need to select the element on the opposite end. In addition, a condition that L [3] does not necessarily have to be the maximum brightness Vmax is added so that the element drawn by subtracting 1V does not have the minimum brightness. 8 un
The derflow condition compensates for this.

Each step of FIG. 8 will be described.

First, it is determined whether or not the brightness L [3] at the position of the center of gravity is smaller than the maximum brightness Vmax (step 1
1). When the brightness L [3] at the position of the center of gravity is equal to or higher than the maximum brightness Vmax, this process ends.

The brightness L [3] at the center of gravity is the maximum brightness Vm.
If smaller than ax, V = {(Vmax-L
V is calculated by [3]) / 3} (step 1
2).

Next, in order to determine which of L [1] and L [5] has the lowest luminance, it is determined whether L [1] is smaller than L [5] (step 13). .

When L [1] is smaller than L [5],
It is determined whether the result of subtracting 1V from L [5] is smaller than L [1] (step 14).

The result of subtracting 1 V from L [5] is L [1].
If it does not become smaller, proceed to step 6 without changing the value of V. If the result of subtracting 1V from L [5] is smaller than L [1], V = (L [5] −L
After changing the value of V by [1]) (step 1
5) Go to step 16.

In step 16, it is determined whether or not the result of subtracting 2V from L [2] is smaller than L [1].

The result of subtracting 2V from L [2] is L [1].
If it does not become smaller, proceed to step 18 without changing the value of V. When the result of subtracting 2V from L [2] is smaller than L [1], V = {(L [2]
After changing the value of V by -L [1]) / 2} (step 17), the process proceeds to step 18.

In step 18, the values of L [2], L [3] and L [5] are changed based on the following equation (2).

[0076]

In step 13 above, L [1] is L
When it is equal to or more than [5], it is determined whether or not the result of subtracting 1V from L [1] is smaller than L [5] (step 19). The result of subtracting 1V from L [1] is L
If it does not become smaller than [5], the process proceeds to step 21 without changing the value of V. If the result of subtracting 1V from L [1] is smaller than L [5], V = (L
After changing the value of V by [1] -L [5]) (step 20), the process proceeds to step 21.

In step 11, it is determined whether or not the result of subtracting 2V from L [4] is smaller than L [5].

The result of subtracting 2V from L [4] is L [5].
If it does not become smaller, the process proceeds to step 23 without changing the value of V. If the result of subtracting 2V from L [4] is smaller than L [5], V = {(L [4]
After changing the value of V by -L [5]) / 2} (step 22), the process proceeds to step 23.

In step 21, the values of L [1], L [3] and L [4] are changed based on the following equation (3).

[0081]

(3) Step 3: Centering of brightness levels

In step 23, the brightness level is concentrated at the center of gravity of the horizontal white line, and the vertical width of the horizontal white line is narrowed and emphasized. Also in step 3, the brightness in the horizontal white line is adjusted so that the maximum brightness in the horizontal white line does not exceed the line maximum brightness Vmax and the center of gravity and the total brightness do not change.

FIG. 9 shows the detailed processing procedure of step 3.

First, in order to determine which of the luminance levels L [2] and L [4] adjacent to the center of gravity is to be raised, L [1] is calculated from L [5]. It is determined whether or not it is small (step 31).

When L [1] is smaller than L [5],
W is calculated by W = {(L [5] -L [1]) / 2} (step 32).

It is determined whether or not the result of adding 3 W to L [4] is larger than the luminance L [3] at the position of the center of gravity (step 33). If the result of adding 3W to L [4] does not become larger than L [3], the process proceeds to step 35 without changing the value of W. The result of adding 3W to L [4] is L
If it is larger than [3], W = {(L [3] -L
After changing the value of W by [4]) / 3} (step 34), the process proceeds to step 35.

In step 35, it is determined whether or not the result of subtracting W from L [2] is smaller than L [1].

If the result of subtracting W from L [2] does not become smaller than L [1], the process proceeds to step 37 without changing the value of W. The result of subtracting W from L [2] is L
If smaller than [1], W = (L [2] −L
After changing the value of W by [1]) (step 3
6) and then to step 37.

At step 37, the values of L [2], L [4] and L [5] are changed based on the following equation (4).

[0091]

In step 31, L [1] is L
When [5] or more, W = {(L [1] -L
[5]) / 2} to calculate W (step 3
8).

It is determined whether or not the result of adding 3 W to L [2] is larger than the luminance L [3] at the position of the center of gravity (step 39). If the result of adding 3W to L [2] does not become larger than L [3], the process proceeds to step 41 without changing the value of W. The result of adding 3W to L [2] is L
If it is larger than [3], W = {(L [3] -L
After changing the value of W by [2]) / 3} (step 40), the process proceeds to step 41.

In step 41, it is determined whether the result of subtracting W from L [4] is smaller than L [5].

If the result of subtracting W from L [4] does not become smaller than L [5], the process proceeds to step 43 without changing the value of W. The result of subtracting W from L [4] is L
When it is smaller than [5], W = (L [4] −L
After changing the value of W by [5]) (step 4)
2) Go to step 43.

In step 43, the values of L [1], L [2] and L [4] are changed based on the following equation (5).

[0097]

(4) Step 4: Instruction to the line drawing circuit The element (average brightness value) in the work array pattern obtained in steps 1 to 3 is written in the corresponding position of the line memory unit 11. .

In the line drawing circuit 15, only when the information on the presence / absence of movement of the horizontal white line obtained from the line maximum luminance detection circuit 12 indicates the presence of movement, the line luminance calculation circuit 14 follows the instruction to the horizontal white line. Draw the brightness correction value. Therefore, when the information on the presence / absence of movement of the horizontal white line obtained from the line maximum luminance detection circuit 12 indicates that there is no movement, the line drawing circuit 15 does nothing. It should be noted that the line drawing circuit 15 sets a written flag to the pixel for which the correction value has been written, as described in the line memory unit 11.

The line drawing circuit 15 is provided in the line memory unit 11.
The data written from 1 to 1 are sequentially output closer to the output end as the input data is updated, and are eventually output.

In the above embodiment, the case where the horizontal white line in the progressive scan image obtained by performing the sequential scan conversion of the interlaced scan image is corrected has been described. It can also be applied when correcting a horizontal white line in an image.

In the above embodiment, the correction is performed on the horizontal white line in which the brightness value of the horizontal line is relatively higher than the brightness value of the peripheral portion, but the brightness value of the horizontal line is The horizontal black line, which is relatively lower than the luminance value of the peripheral portion, can be corrected by the same method.

To correct the horizontal black line, a first brightness inverting circuit for inverting the brightness level of the 2: 1 interlace signal (input image signal) is added to FIG. The signal whose brightness has been inverted by is sent to the motion vector detecting circuit 1, the first field memory 2, the inter-field interpolating section 3 and the intra-field interpolating section 4, and the horizontal line correction circuit 7 is followed by a horizontal line. A second brightness inverting circuit for inverting the brightness level of the output signal of the correction circuit 7 may be added.

[0104]

According to the present invention, horizontal line edges can be emphasized in a progressive scan image obtained by progressively converting an interlaced scan image or in a scaled image obtained by scaling processing, and aliasing can be performed.・ It becomes possible to reduce crawling interference.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of a scan conversion circuit.

FIG. 2 is a block diagram showing a configuration of a horizontal line correction circuit 7.

FIG. 3 is a schematic diagram showing a configuration of a line memory unit.

FIG. 4 is a schematic diagram for explaining a method for searching a horizontal white line.

FIG. 5 shows an example in which the vertical width of a set of pixels with high brightness detected by a horizontal line detection circuit is 4 lines or less;
FIG. 7 is a schematic diagram showing an example in which the vertical width of a set of detected pixels with high brightness exceeds four lines in total.

FIG. 6 is a flowchart showing an overall processing procedure by the line luminance calculation circuit 14.

FIG. 7 is a schematic diagram showing a work array pattern.

FIG. 8 is a flowchart showing a processing procedure of step 2 in FIG.

9 is a flowchart showing a processing procedure of step 3 in FIG.

FIG. 10 is a schematic diagram showing an original image.

FIG. 11 is a schematic diagram showing an image obtained by inter-field interpolation.

FIG. 12 is a schematic diagram showing an image obtained by interline interpolation (intrafield interpolation).

FIG. 13 is a schematic diagram showing an image obtained by motion compensation interpolation.

[Explanation of symbols]

7 Horizontal line correction circuit 11 line memory section 12-line maximum brightness detection circuit 13 Horizontal line detection circuit 14 line brightness calculation circuit 15 line drawing circuit

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Toshiya Iinuma             2-5-3 Keihan Hondori, Moriguchi City, Osaka Prefecture             Within Yo Denki Co., Ltd. (72) Inventor Masahiko Yoshiyama             2-5-3 Keihan Hondori, Moriguchi City, Osaka Prefecture             Within Yo Denki Co., Ltd. F term (reference) 5B057 AA01 CA08 CA12 CA16 CB08                       CB12 CB16 CD06 CH01 CH11                       DA16                 5C063 AA01 AA06 AB03 AC01 BA04                       BA09 BA10 BA12 CA05 CA07                 5C082 AA02 BA12 BA41 BC16 BC19                       BD09 CA81 CA84 DA76 MM10

Claims (2)

[Claims] 1. A horizontal line correction method for correcting a luminance value in a horizontal line in a processed image obtained by subjecting an original image to sequential scanning conversion processing or scaling processing, wherein the horizontal line in the processed image is corrected. The first step of detecting the horizontal brightness, the second step of acquiring the highest brightness level in the horizontal line from the original image of the surrounding fields, and the brightness level at the center of the vertical width of the horizontal line to the highest brightness level acquired in the second step. A horizontal line correction method, comprising: a third step of correcting so as to bring them closer to each other. 2. In the third step, when correcting the brightness level at the center of the vertical width of the horizontal line, the brightness levels of other parts in the horizontal line are corrected so that the center of gravity of the horizontal line and the total brightness do not change. The horizontal line correction method according to claim 1, further comprising a fourth step.