JP2000115720A - Scanning line interpolation device and scanning line interpolation method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve deterioration in image quality attended with interpolation by generating an interpolation signal from a combination where correlation among adjacent pixels in the vertical and oblique directions of upper and lower scanning lines in highest in a moving picture area and generating an interpolation signal from a signal of a just above field in a still picture in the case of converting an interlace signal into a noninterlace signal. SOLUTION: In the case of a moving picture, a 1st candidate set where a pixel point just above an interpolation point is made to a 1st point and pixel point just under the interpolation point is made to a 2nd point, a 2nd candidate set where a pixel point to the left and just above the interpolation point is made to a 1st point and a pixel point to the right and just under the interpolation point is made to a 2nd point, and a 3rd candidate set where a pixel point to the right of the interpolation point is made to a 1st point and a pixel point to the left and just under the interpolation point is made to a 2nd point are set. Furthermore, a set among the plural interpolation candidates where the correlation of the luminance between the 1st and 2nd points is higher is selected. Or a set where a difference of the luminance between the 1st and 2nd points is least is selected. Furthermore, a main value of the luminance of the 1st and 2nd points of the selected candidate set is made as the luminance of the interpolation point.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a case where an image signal is displayed on a display device in which the number of scanning lines of an image signal is different from the number of pixels, or where interpolation is performed between scanning lines of an interlaced scanning signal. The present invention relates to a scanning line interpolation method and a scanning line interpolation device to be used.

[0002]

2. Description of the Related Art Conventionally, a double-speed display CRT (Cathode
Ray Tube (cathode ray tube) display and LCD (Liquid)
d Crystal Display: liquid crystal display) or PD
Scan line interpolation is used for displaying an image on a P (Plasma Display Panel).

The scanning line interpolation generally used in the above-described display uses a separate scanning line interpolation method for a still image and a moving image, or uses a fixed scanning line interpolation method. That is, the normal scanning line interpolation or fixed scanning line interpolation employs writing twice or vertical interpolation using an average of vertical scanning lines.

[0004]

In the above twice writing, the same signal as the scanning line above (or below) the scanning line to be interpolated is used as the interpolation signal. In this case, the vertical sharpness is maintained to some extent, but the diagonal lines are jagged, and many folds occur during moving images.

[0005] On the other hand, in vertical interpolation, the jaggies of oblique lines are improved to some extent as compared with writing twice, but the vertical resolution is reduced. 8 and 9 are explanatory diagrams for explaining an example of such a conventional interpolation method. FIGS. 8 (a) and 9 (a) show a state where no interpolation is performed, and FIGS. (B) shows an example of vertical interpolation. In these figures, solid lines indicate main scanning lines, and broken lines indicate interpolation scanning lines.

Further, each of the bright points (pixels) constituting these scanning lines and interpolation scanning lines is shown by a circle, white circles are lit (brightness 100%), black circles are off (brightness 0), and hatched circles are halftones. Lighting (luminance 50%) is shown.

[0007] As shown in these figures, in the case of the vertical interpolation method, a bright point of halftone luminance which does not originally exist in the interpolation scanning line occurs. As a result, the edge of the figure is dull and jagged.

FIGS. 10 and 11 are explanatory diagrams showing an example of an interpolation result when a signal having a high vertical resolution is continuously input in the above-described prior art.
FIGS. 10A and 11A show a state where no interpolation is performed, and FIGS. 10B and 11B show an example where vertical interpolation is performed. As shown in these figures, when the scanning line interpolation is performed only in the moving image area, the vertical frequency characteristic is reduced by half, and the entire image is blurred.

The present invention has been made under such a background, and realizes a smooth oblique line by suppressing generation of oblique lines during scanning line interpolation in a moving image area, and realizes a vertical oblique line in a still image area. It is an object of the present invention to provide a scanning line interpolation device and a scanning line interpolation method that reduce a decrease in resolution.

[0010]

In order to solve the above-mentioned problems, according to the present invention, the first to second k (k is a positive integer) image in which image signals are sequentially delayed. Signal delay means, first and second scanning line storage means for storing and holding one scanning line of the image signal, and image signal for one scanning line stored in the first scanning line storage means. A second to first scanning line signal delay unit for sequentially delaying, and a first calculating unit for calculating a difference between the image signal value and the image signal value for one scanning line stored in the first scanning line storage unit. , A second subtraction means for calculating a difference between an output value of the first image signal delay means and an output value of the second k-th scanning line signal delay means, and the 2k image signal Calculating a difference between an output value of the delay unit and an output value of the first scanning line signal delay unit; A subtraction unit 2k + one, the first
Comparing means for comparing each of the absolute values of the differences calculated by the subtracting means from (k) to (k) with the image signal value and the image signal value for one scanning line stored in the first scanning line storage means. A first calculating means for calculating an average value of the first image signal delay means, and a second calculating means for calculating an average value of an output value of the first image signal delay means and an output value of the second k-th scanning line signal delay means. .. Based on a comparison result of the 2k + 1 arithmetic means for calculating an average value of the output value of the 2k image signal delay means and the output value of the first scanning line signal delay means, and the comparison means From the first calculation means, the second k +
A first selecting means for selectively selecting and outputting any one of the output values of the first calculating means, and a third means for storing and holding one scanning line of the output signal of the second scanning line storing means. Scanning line storage means, motion calculation means for calculating a difference between an output signal value of the third scanning line storage means and the image signal value, and a third output signal value calculated by the motion calculation means; A motion determining unit that detects a motion of the image signal based on a difference from an image signal value; an output signal of the first selecting unit and the second scanning line storing unit based on a determination result of the motion determining unit A second selecting means for selectively outputting any one of the output signals of the first and second output signals, and a fourth scanning line storing means for storing and holding one scanning line of the output signal of the second selecting means. The image signals for one scanning line stored in the first scanning line storage means are sequentially delayed. A first to a k-th interpolated scanning line signal delay unit, a fifth scanning line storage unit for storing and holding one scanning line of an output signal of the k-th interpolated scanning line signal delay unit, The output signal of the scanning line storage means of the fourth and the fifth
Switching means for alternately switching and outputting the output signal of the scanning line storage means. Also, in the invention according to claim 2, in the scanning line interpolation device according to claim 1, the motion determination unit includes the third output signal value calculated by the motion calculation unit and the image signal. When the difference between the third output signal value and the image signal value is determined to be a moving image, the difference between the third output signal value and the image signal value calculated by the motion calculation means is equal to or less than the predetermined value. Is determined as a still image. According to a third aspect of the present invention, in the scanning line interpolating apparatus according to any one of the first and second aspects, the second selecting unit may be configured so that the image signal is a moving image. Is the first
Selecting the output signal of the selection means and supplying the selected signal to the fourth scanning line storage means, and selecting the output signal of the second scanning line storage means if the image signal is a stop image, and selecting the output signal of the second scanning line storage means. 4
In the scanning line storage means. Also,
According to a fourth aspect of the present invention, in the scanning line interpolation apparatus according to any one of the first to third aspects, the comparing means is calculated by the first to the (2k + 1) th subtracting means. Detect the n-th in which the absolute value of the difference is the minimum,
The first selection means is configured to determine the second calculation result from the first calculation means corresponding to the n-th detected by the comparison means.
It is characterized in that any one of the output values of the (k + 1) calculating means is selectively output. According to a fifth aspect of the present invention, in the scanning line interpolation device according to any one of the first to fourth aspects, the first to 2k + 1
Calculating means for calculating the sum of the image signal value and the image signal value for one scanning line stored in the first scanning line storage means; and the first image signal Second adding means for calculating the sum of the output value of the delay means and the output value of the second k-th scanning line signal delay means;... The output value of the second k-th image signal delay means and the first scanning It is characterized by comprising a 2k + 1 adding means for calculating the sum of the output value of the line signal delay means and a dividing means for calculating a half of the output value of the first selecting means. Claim 6
In the invention described in (1), there is provided a scanning line interpolation method for interpolating between two adjacent horizontal scanning lines among a plurality of horizontal scanning lines constituting a two-dimensional image by an interpolation scanning line. , For each of the arbitrary interpolation points in each of the interpolation scan lines, the first of the first points in the horizontal scan line immediately above the interpolation scan line and the first in the horizontal scan line immediately below the interpolation scan line And a plurality of candidate interpolation sets are set with the second point that is located point-symmetrically at the interpolation point, and one of the plurality of candidate interpolation sets is selected,
When the plane image is a moving image, the luminance value of the interpolation point is calculated based on the luminance value of the first point and the luminance value of the second point that form the selected interpolation candidate set. It is characterized by the following. According to a seventh aspect of the present invention, in the scanning line interpolation method according to the sixth aspect, when the plane image is a stop image, the horizontal scanning line signal immediately above the interpolation scanning line is provided. The brightness value of an arbitrary point is set as the brightness value of the corresponding interpolation point. Claim 8
In the scanning line interpolation method according to any one of claims 6 and 7, the plurality of horizontal scanning lines and each of the plurality of interpolation scanning lines are mutually adjacent scanning lines. The left and right positions are composed of a plurality of corresponding pixels, and each of the first point, the second point, and the interpolation point is based on the pixel. According to the ninth aspect of the invention, in the scanning line interpolation method according to the eighth aspect, for each of the arbitrary interpolation points on each of the interpolation scanning lines, a pixel point immediately above the interpolation point is determined. A first interpolation candidate set in which the first point is the pixel point immediately below the interpolation point and the second point is the second point; and a pixel point on the left immediately above the interpolation point is the first point and the interpolation point is the first point. A second interpolation candidate set in which the pixel point immediately to the right of the interpolation point is the second point, and a pixel point immediately to the right of the interpolation point is the first point and the left pixel immediately below the interpolation point is the first point. A third interpolation candidate set having the next pixel point as the second point is set. According to the tenth aspect of the present invention, in the scanning line interpolation method according to any one of the sixth to ninth aspects,
One of the plurality of interpolation candidate sets having the highest correlation between the first point and the second point is selected. Also, in the invention according to claim 11, in the scanning line interpolation method according to any one of claims 6 to 10, the luminance of the first point in the plurality of interpolation candidate sets is determined. A set is selected in which the difference between the value and the luminance value of the second point is the smallest. According to a twelfth aspect of the present invention, in the scanning line interpolation method according to any one of the sixth to eleventh aspects, the luminance of the first point forming the selected interpolation candidate set is determined. The average value of the value and the luminance value of the second point is set as the luminance value of the interpolation point.

According to the present invention, in a portion where an interlaced (interlaced scanning) signal is converted into a non-interlaced signal, in the moving image area, the correlation between adjacent pixels in the vertical and oblique directions of the upper and lower scanning lines is detected and detected. An interpolation signal is created from the combination having the highest correlation, and in a still image area, an interpolation signal is created from the immediately above field signal.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below. FIG. 1 is a block diagram showing a configuration of a scanning line interpolation device according to one embodiment of the present invention. In the present embodiment, 1 and 16, 17, 22, and 26 are scanning line memories for storing and holding one of the scanning lines constituting the screen, 2-1 and 2-2 (2), 4- 1, 4-2 (4) and 12 are delay circuits for delaying only one pixel (bright point) on one scanning line.

The above-described scanning line memories 1, 16, 17, 22
And 26 are for delaying the digitally converted video signal by one scanning line period.
It has a (First In First Out) register, and sequentially outputs input data. Further, the delay circuits 2-1 and 2-2, 4-1 and 4-2 and 12 are, for example, D-FFs.
(D flip-flop).

6-1, 6-2 and 6-3 (6) are subtractors, 9
-1, 9-2, 9-3 (9) are adders. And 18 is a comparison circuit, 19, 21 and 25 are switching circuits,
Reference numeral 20 denotes a computing unit that computes a half.

In such a configuration, the input video signal Svi is used as a scanning line memory 1 for storing and holding one scanning line, a scanning line memory 26 for motion detection, and a delay circuit 4-2.
The horizontal tap signals of the upper and lower scanning lines are generated by the delay circuits 2-1, 2-1 and 4-1.

The signals in the moving image area are subtracted by subtracters 6-1, 6-2, 6
-3 and processed by adders 9-1, 9-2, 9-3,
Further, the switching circuit 19 is controlled based on the result of the comparison circuit 18 and outputs an interpolation signal Cmp.

After the signal level of the interpolation signal Cmp is halved by the arithmetic unit 20, the signal becomes one input of a switching circuit 25 controlled by a motion determination circuit 24, which will be described later. Is selected.
The signal output from the switching circuit 25 is input to the scanning line memory 17 for double speed conversion, and is compressed in the time axis direction.

Similarly, the video signal Svi is also compressed in the time axis direction by the scanning line memory 16 for double speed conversion, these are alternately selected by the switching circuit 21, and
Output as vo.

On the other hand, the signal in the inhibited image area is
6 and the other input of the switching circuit 25 described above. Further, the difference from the video signal Svi is obtained by being input from the scanning line memory 26 to the subtractor 23 via the scanning line memory 22.

The motion judging circuit 24 detects a motion in the video signal Svi based on the difference signal. That is, if the value of the difference signal exceeds a predetermined value set in advance, it is determined that the image is a moving image, and if it is less than the predetermined value, it is determined that the image is a stop image. Thus, in the case of the signal of the still image area, the signal from the scanning line memory 26 is input to the scanning line memory 17 for double speed conversion via the switching circuit 25.

FIG. 2 is an explanatory diagram for explaining the operation of the present embodiment. Generally, as shown in FIG. 2, a plurality of horizontal scanning lines 30-1, 30-2,..., 30-n-1, 30-n (hereinafter referred to as necessary) (Hereinafter simply referred to as a scanning line 30 in accordance with).

Note that the number of the scanning lines 30 greatly differs depending on the broadcasting system, the number of pixels constituting an image, and the like, and a description thereof will be omitted. Each of the plurality of scanning lines 30 further includes a plurality of bright spots 30a-1,
30a-n (hereinafter, simply referred to as bright spots 30a as necessary).

In the present embodiment, one interpolated scanning line 32 is inserted between each two adjacent scanning lines 30. In this case, an interpolation scanning line 32-1 is inserted between the scanning line 30-1 and the scanning line 30-2 ... between the scanning line 30-n-1 and the scanning line 30-n. The interpolation scanning line 32-n is inserted. Note that each of the above-described plurality of interpolation scanning lines 32 also has a plurality of bright spots 32a, 32a,.
・ Consists of

Hereinafter, a method of interpolating between the scanning line 30-y and the scanning line 30-y + 1 will be described with reference to the bright spot 30a on the scanning line 30-y.
The relationship between (x, y) and the bright spot 30a (x, y + 1) on the scanning line 30-x + 1 corresponding to the horizontal position will be described as an example.

In this case, the bright spot 32 on the interpolation scanning line 32-y
The scanning line 30-y and the scanning line 30-y + 1 are interpolated by a (x, y), and the correction value Cm (x, y) which is the luminance at the bright spot 32a (x, y) is scanned. The bright spot 30a (x, y) on the line 30-y and its adjacent bright spots 30a (x-1, y) and bright spots 3
0a (x + 1, y) (Br (x, y), Br (x-1,
y), Br (x + 1, y)), and bright spot 3 on scan line 30-y + 1
0a (x, y + 1) and its adjacent bright spot 30a (x-1, y +
1) and the brightness value (Br (x,
y + 1), Br (x + 1, y + 1), and Br (x-1, y + 1)).

In FIG. 1, an input video signal Svi
Are supplied to the scanning line memory 1, the scanning line memory 12, and the delay circuit 4-2. The output of the scanning line memory 1 is input to the delay circuit 2-1 and the output is input to the delay circuit 2-2. Similarly, the output of the delay circuit 4-2 is
Is input to

The output of the scanning line memory 1 is the scanning line 3
The output value of the delay circuit 2-1 corresponds to the brightness value Br (x, y) on the scanning line 30-y.
The output of the delay circuit 2-2 is a luminance value B on the scanning line 30-y.
r (x + 1, y).

Similarly, the input video signal Svi corresponds to the luminance value Br (x, -1y) +1 on the scanning line 30-y + 1, and the output of the delay circuit 4-2 is the scanning line 30-y. +1 corresponding to the luminance value Br (x, y + 1). The output of the delay circuit 4-1 is the scanning line 30-y
+1 corresponding to the luminance value Br (x + 1, y + 1).

The subtractor 6-1 calculates the luminance value B on the scanning line 30-y.
A difference value between r (x−1, y) and the luminance value Br (x + 1, y + 1) on the scanning line 30-y + 1 (relationship with the dashed line A in FIG. 2) is obtained. The value is input to the comparison circuit 18.

Similarly, the subtractor 6-2 outputs the luminance value Br (x, y) on the scanning line 30-y and the luminance value Br (x, y + 1) on the scanning line 30-y + 1.
(Represented by the dashed-dotted line B in FIG. 2), and the subtractor 6-3 calculates the luminance value Br (x + 1, y) on the scanning line 30-y and the scanning line 30-y + 1. The difference value from the above luminance value Br (x-1, y + 1) (FIG.
The relationship between the one-dot chain line C in FIG.
To enter.

The comparison circuit 18 to which the difference values are inputted from each of the subtracters 6-1, 6-2, and 6-3 takes the absolute value of each of the three inputted difference values, and calculates the minimum value among them. Detect things.

On the other hand, the adder 9-1 outputs the luminance value Br (x-1, y) on the scanning line 30-y and the luminance value Br (x + 1, y +) on the scanning line 30-y + 1.
The value (1) is added to (1), and is input to the switching circuit 19.

Similarly, the adder 9-2 outputs the luminance value Br (x, y) on the scanning line 30-y and the luminance value Br (x, y + 1) on the scanning line 30-y + 1.
(Relationship with the chain line B in FIG. 2), and the adder 9-3 calculates the luminance value Br (x + 1, y) on the scanning line 30-y and the scanning line 30-y + 1. An addition value with the above luminance value Br (x−1, y + 1) is obtained, and input to the switching circuit 19, respectively.

The switching circuit 19 to which the added value has been input from each of the adders 9-1, 9-2 and 9-3 is connected to the comparison circuit 1 described above.
8 is selected as an addition value corresponding to the combination indicating the minimum difference value detected.

The signal level of the interpolation signal Cmp selectively output from the switching circuit 19 is halved by the arithmetic circuit 20 and input to the scanning line memory 17 for double speed conversion.
The scanning line memory 17 for double-speed conversion compresses the time axis by half by reading it out with a clock signal (both not shown) having a frequency twice as high as the write clock.

Similarly, the output of the delay circuit 12 is input to the scanning line memory 16 for double-speed conversion, and the content of the scanning line memory 16 is read out with a clock signal having a frequency twice as high as the write clock, thereby shifting the time axis. Compress by half.

Finally, the switching circuit 21 switches the output of the scanning line memory 16 for double-speed conversion and the output of the scanning line memory 17 for double-speed conversion for each horizontal scanning line period and outputs it. The output of the scanning line memory 16 for double speed conversion is an output on the original signal side, and the output of the scanning line memory 17 for double speed conversion is an output on the interpolation signal side.

As described above, the absolute value of the difference between the luminance values of the pixels located in the vertical and diagonal directions (diagonal direction, point symmetry direction) on the scanning lines above and below the pixel forming the interpolation signal. Is determined, and the one with the smallest difference value is determined as the combination having the highest correlation, and the average value of the luminance between the pixels is set as the interpolation value.

As a result, a decrease in the vertical resolution at the time of scanning line interpolation, particularly a decrease in the oblique resolution, is reduced, and the occurrence of jagged oblique lines is suppressed. As a result, a smooth oblique line is realized.

FIGS. 3 and 4 are explanatory diagrams for explaining an example of interpolation of a restricted image area in the interpolation processing according to the present embodiment. FIGS. 3 (a) and 4 (a) show a state where no interpolation is performed. 3B and FIG. 4B show examples in which the interpolation processing according to the present embodiment has been performed. In these figures, solid lines indicate main scanning lines, and broken lines indicate interpolation scanning lines.

Further, each of the bright spots (pixels) constituting these scanning lines and interpolation scanning lines is indicated by a circle, white circles are lit (luminance 100%), black circles are unlit (luminance 0), and hatched circles are halftones. Lighting (luminance 50%) is shown. As shown in these figures, in the present embodiment, correlation in an oblique direction is used, and ideal interpolation is performed.

FIGS. 5 and 6 are explanatory diagrams for explaining an example of interpolation of a moving image area in the interpolation processing according to the present embodiment. FIGS. 5 (a) and 6 (a) show a state where no interpolation is performed. FIG. 5B and FIG. 6B show examples in which the interpolation processing according to the present embodiment has been performed. Also in these figures, solid lines indicate main scanning lines, and broken lines indicate interpolation scanning lines.

As described above, in the present embodiment, when a still image area is detected, the signal of the previous field is used as an interpolation signal, thereby obtaining the signal shown in FIG. 5B or FIG.
Are obtained, and an image without blur can be obtained even in a still image area.

In the above-described embodiments, the number of combinations in the horizontal direction for detecting the correlation is set to three, but any number larger than this is within the scope of the present invention. That is, the interpolation step according to the present invention is represented by k (k = 1, 2,.
3, 4, ...), the number of comparison target combinations is 2k
It becomes +1.

FIG. 7 is a block diagram showing the configuration of a scanning line interpolation apparatus according to an application of the present invention. In FIG. 7, parts corresponding to the respective parts shown in FIG. 1 are given the same reference numerals, and descriptions thereof will be omitted.

In the example shown in FIG. 7, in order to determine the smoothness of interpolation of an oblique line in a direction close to horizontal, n delay circuits 2 and 4 (n = 2k) and delay circuit 12 are m
(M = k) and are enlarged in the horizontal direction. Correspondingly, L subtractors 6 and adders 9 (L = n + 1)
Provide.

Then, the comparison circuit 18a to which the difference values have been input from each of the subtracters 6-1, 6-2,..., 6-L obtains the absolute value D for each of the input L sets of difference values. . That is, when obtaining the interpolation value I at the point (x, y) on the screen, the calculation of each absolute value D can be represented by the following equation.

(Equation 1)

Further, the comparison circuit 18a calculates the minimum values of Br (x + Min, y + 1) and Br (
x-Min, y) is detected (Min takes an integer between -k and k).

On the other hand, the switching circuit 19a, to which the added value is input from each of the adders 9-1, 9-2,..., 9-L, forms a combination indicating the minimum difference value detected by the comparison circuit 18a. Select the corresponding sum.

The signal level of the interpolation signal Cmp selectively output from the switching circuit 19a in this manner is
The data is input to the scanning line memory 17 for double speed conversion. Here, the correction value I output from the arithmetic circuit 20 is
It can be represented by the following equation. I = (Br (x + Min, y + 1) + Br (x-Min, y)) / 2 (2)

In each of the above embodiments, smooth scanning line interpolation is realized by the physical configuration. However, similar processing can be performed by software by using, for example, a digital signal processor or the like. is there.

[0052]

As described above, according to the present invention, for each of the arbitrary interpolation points on each of the interpolation scanning lines, the arbitrary first point on the horizontal scanning line immediately above the interpolation scanning line and the interpolation scanning are obtained. In the horizontal scanning line immediately below the line, a plurality of interpolation candidate sets are set in which the first point and the second point located point-symmetrically at the interpolation point are set, and one of the plurality of interpolation candidate sets is set.
When a set is selected and the plane image is a moving image, the luminance value of the interpolation point is calculated based on the luminance value of the first point and the luminance value of the second point that form the selected candidate interpolation set. . When the plane image is a stop image, the luminance value of an arbitrary point of the horizontal scanning line signal immediately above the interpolation scanning line is set as the luminance value of the corresponding interpolation point. Further, each of the plurality of horizontal scanning lines and the plurality of interpolation scanning lines is constituted by a plurality of pixels whose left and right positions correspond to the adjacent scanning lines, and each of the first point, the second point, and the interpolation point is a pixel. Is the unit. Further, for each of the arbitrary interpolation points in each of the interpolation scanning lines, a first interpolation candidate set in which a pixel point immediately above the interpolation point is a first point and a pixel point immediately below the interpolation point is a second point, A second interpolation candidate set in which the pixel point on the left immediately above the interpolation point is the first point and the pixel point on the right immediately below the interpolation point is the second point; A third interpolation candidate set is set in which the pixel point is the first point and the pixel point immediately to the left immediately below the interpolation point is the second point. Further, one of the plurality of interpolation candidate sets having the highest correlation between the first point and the second point is selected. Further, from among the plurality of interpolation candidate sets, one set having the smallest difference between the luminance value of the first point and the luminance value of the second point is selected. In addition, since the average value of the luminance value of the first point and the luminance value of the second point forming the selected interpolation candidate set is set as the luminance value of the interpolation point, in the moving image area, the diagonal line at the time of scanning line interpolation is used. The effect of realizing a scanning line interpolation device and a scanning line interpolation method that realizes a smooth oblique line by suppressing the occurrence of jaggedness and reduces a decrease in vertical resolution in a still image area can be obtained.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a configuration of a scanning line interpolation device according to an embodiment of the present invention.

FIG. 2 is an explanatory diagram illustrating an operation of the embodiment.

FIG. 3 is an explanatory diagram illustrating an example of interpolation of a restrained image area in the interpolation processing according to the embodiment;

FIG. 4 is an explanatory diagram illustrating an example of interpolation of a restrained image area in the interpolation processing according to the embodiment;

FIG. 5 is an explanatory diagram illustrating an example of interpolation of a moving image area in the interpolation processing according to the embodiment;

FIG. 6 is an explanatory diagram illustrating an example of interpolation of a moving image area in the interpolation processing according to the embodiment;

FIG. 7 is a block diagram showing a configuration of a scanning line interpolation device according to an application example of the present invention.

FIG. 8 is an explanatory diagram illustrating an example of a conventional interpolation method.

FIG. 9 is an explanatory diagram illustrating an example of a conventional interpolation method.

FIG. 10 is an explanatory diagram showing an example of an interpolation result when a signal having a high vertical resolution is continuously input in the related art.

FIG. 11 is an explanatory diagram showing an example of an interpolation result when a signal having a high vertical resolution is continuously input in the related art.

[Explanation of symbols]

1. Scanning line memory (first scanning line storage means) 2-1 2-2 ... 2-n delay circuit (scanning line signal delay means) 4-1 4-2 ... 4-n delay circuit (Image signal delay means) 6-1, 6-2 ... 6-L subtractor (subtraction means) 9-1, 9-2 ... 9-L Adder (addition means) 12-1, 12- 2 ... 12-m delay circuit (interpolated scanning line signal delay means) 16 scanning line memory (fifth scanning line storage means) 17 scanning line memory (fourth scanning line storage means) 18, 18a comparison circuit ( 19, 19a Switching circuit (first selecting means) 20 Computing unit (division means) 21 Switching circuit (switching means) 22 Scanning line memory (third scanning line storing means) 23 Subtractor (motion calculating means) 24 motion determination circuit (motion determination means) 25 switching circuit (second selecting means) 26 scanning line memory (second scanning line storage means) 30, 30-1, 30-2 ... 30-n scanning lines (horizontal scanning lines) 30-y, 30-y + 1 scanning lines 30a, 30a-1, 30a-2 ... 30a-n bright spots 32, 32-1, 32-2 ... 32-n-1 Interpolated scanning line 32a ... Bright point (interpolated point)

 ──────────────────────────────────────────────────続 き Continued on front page F-term (reference)

Claims (12)

[Claims] 1. A first and a second means for sequentially delaying an image signal.
k (k is a positive integer) image signal delay means (4-1, 4-2
... 4-n), first and second scanning line storage means (1, 26) for storing and holding one scanning line portion of the image signal, and the first and second scanning line storage means stored in the first scanning line storage means. 2k to first scanning line signal delay means (2-n... 2-2, 2-1) for sequentially delaying image signals for one scanning line, the image signal value and the first scanning line First subtraction means (6-1) for calculating a difference between the image signal value for one scanning line stored in the storage means, and an output value of the first image signal delay means and the 2k scan Second subtraction means (6-2) for calculating the difference between the output value of the line signal delay means and the output value of the 2k image signal delay means and the output of the first scanning line signal delay means A 2k + 1 subtraction means (6-L) for calculating a difference between the absolute value and the absolute value of the difference calculated by the first to the 2k + 1 subtraction means. Comparison means for comparing (18, 18a)
First arithmetic means for calculating an average value of the image signal value and the image signal value for one scanning line stored in the first scanning line storage means; and first image signal delay means A second calculating means for calculating an average value of the output value of the second k-th scanning line signal delay means and the output value of the second k-th scanning line signal delay means, and the output value of the second k-th image signal delay means and the first scanning line A second (k + 1) th calculating means for calculating an average value with an output value of the signal delaying means; and one of the output values of the second (k) th calculating means from the first calculating means based on a comparison result by the comparing means.
First selecting means (19, 19) for selectively outputting one of
a), a third scanning line storage means (22) for storing and holding one scanning line of the output signal of the second scanning line storage means, and an output signal value of the third scanning line storage means and A motion calculating means (23) for calculating a difference between the image signal value and a motion of the image signal based on a difference between the third output signal value and the image signal value calculated by the motion calculating means; A motion judging unit (24), and selectively one of an output signal of the first selecting unit and an output signal of the second scanning line storing unit based on a judgment result of the motion judging unit. A second selecting means (25) for selectively outputting, a fourth scanning line storing means (17) for storing and holding one scanning line of the output signal of the second selecting means, and a first scanning line storage Means for sequentially delaying the image signal for one scanning line stored in the means. Inter-scanning-line signal delay means (12-1, 12-2,..., 12-m); and fifth scanning for storing and holding one scanning line of the output signal of the k-th interpolated scanning-line signal delay means. Line storage means (16)
And a switching unit (21) for alternately switching and outputting an output signal of the fourth scanning line storage unit and an output signal of the fifth scanning line storage unit. apparatus. 2. The motion judging means judges that the image is a moving image if a difference between the third output signal value calculated by the motion calculating means and the image signal value exceeds a predetermined value set in advance. 2. The image processing apparatus according to claim 1, wherein if the difference between the third output signal value calculated by the motion calculation unit and the image signal value is equal to or less than the predetermined value, the image is determined to be a still image. Scan line interpolator. 3. The image processing apparatus according to claim 1, wherein the second selection unit selects an output signal of the first selection unit and supplies the output signal to the fourth scanning line storage unit when the image signal is a moving image. 3. The method according to claim 1, wherein when the signal is a stop image, an output signal of the second scanning line storage unit is selected and supplied to the fourth scanning line storage unit.
The scanning line interpolation device according to any one of the above. 4. The comparing means detects an n-th one in which the absolute value of the difference calculated by the first to the (2k + 1) -th subtracting means is the smallest, and the first selecting means includes 4. The method according to claim 1, wherein one of the output values of the (2k + 1) th arithmetic means is selectively output from the first arithmetic means corresponding to the detected n-th arithmetic means. The scanning line interpolation device according to any one of the above. 5. The first to 2k + 1 calculation means calculates a sum of the image signal value and the image signal value for one scanning line stored in the first scanning line storage means. Adding means (9-1), and second adding means (9-2) for calculating a sum of an output value of the first image signal delay means and an output value of the second k-th scanning line signal delay means. ... 2k + 1 adding means (9-L) for calculating a sum of an output value of the 2k image signal delay means and an output value of the first scanning line signal delay means; 5. A scanning line interpolation apparatus according to claim 1, further comprising a dividing means for calculating a half of an output value of said selecting means. 6. A scanning line interpolation method for interpolating between two adjacent horizontal scanning lines among a plurality of horizontal scanning lines (30) constituting a plane image by an interpolation scanning line (32). An arbitrary interpolation point (32a) in each of the interpolation scanning lines
In each of the above, an arbitrary first point on the horizontal scanning line immediately above the interpolation scanning line and the first point on the horizontal scanning line immediately below the interpolation scanning line are located point-symmetrically at the interpolation point. A plurality of interpolation candidate sets are set as a pair with the second point to be set, and one of the plurality of interpolation candidate sets is selected. When the plane image is a moving image, the selected interpolation is performed. A scanning line interpolation method, wherein a brightness value of the interpolation point is calculated based on a brightness value of the first point and a brightness value of the second point which form a candidate set. 7. When the planar image is a stop image, a luminance value of an arbitrary point of the horizontal scanning line signal immediately above the interpolation scanning line is set as a luminance value of the corresponding interpolation point. The scanning line interpolation method according to claim 6, wherein 8. Each of the plurality of horizontal scanning lines and the plurality of interpolation scanning lines is composed of a plurality of pixels whose left and right positions correspond to adjacent scanning lines, and wherein the first point and the second point are provided. 7. The method according to claim 6, wherein each of said interpolation points is based on said pixel.
8. A scanning line interpolation method according to claim 7. 9. For each of the arbitrary interpolation points on each of the interpolation scanning lines, a pixel point immediately above the interpolation point is defined as the first point, and a pixel point immediately below the interpolation point is defined as the second point. A first interpolation candidate set to be performed, and a second interpolation in which a pixel point on the left immediately above the interpolation point is the first point and a pixel point on the right immediately below the interpolation point is the second point. A candidate set and a third interpolation candidate set in which the pixel point on the right immediately above the interpolation point is the first point and the pixel point on the left immediately below the interpolation point is the second point are set. 9. The method according to claim 8, wherein
3. The scanning line interpolation method according to item 1. 10. The method according to claim 6, wherein one of the plurality of interpolation candidate sets having the highest correlation between the first point and the second point is selected. The scanning line interpolation method according to any one of the above. 11. The method according to claim 6, wherein one of the plurality of interpolation candidate sets having the smallest difference between the luminance value of the first point and the luminance value of the second point is selected. The scanning line interpolation method according to any one of claims 1 to 10. 12. The brightness value of the interpolation point, wherein an average value of a brightness value of the first point and a brightness value of the second point, which form the selected interpolation candidate set, is used as the brightness value of the interpolation point. The scanning line interpolation method according to any one of claims 6 to 11.