JP2002209191A - Video signal converting device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve overall image quality by reducing an image quality difference between a moving picture and a still picture being displayed in a video signal converting device. SOLUTION: This video signal converting device is provided with the pixels number converting part 20 for receiving an interlaced scanning video signal, converting the interlaced scanning video signal into the number of pixels being more than that of an input video signal with a prescribed ratio and outputting the number of pixels and a sequential scanning converting part 10 for converting an output signal of the pixels number converting part into a sequential scanning line signal suitable for image movement.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a video signal converter, and more particularly, to an NTSC system, a PAL system, and a SECAM.
The present invention relates to a video signal conversion device for converting an interlaced scanning line signal having an interlaced scanning structure, such as an HDTV system or an HDTV system, into a desired number of pixels and converting from interlaced scanning to sequential scanning in order to display it on a display.

[0002]

2. Description of the Related Art As conventional video signal converters, Japanese Patent Application Laid-Open Nos. 10-126748 and 10-145817.
Japanese Patent Application Laid-Open Publication No. HEI 9-163, etc. are known.

FIG. 9 is a block diagram showing a configuration example of a conventional video signal conversion device. In FIG. 9, input terminal 1
From, for example, interlaced scanning of the NTSC system
scanning) (hereinafter sometimes abbreviated as 525i. Here, the number “525” indicates the number of scanning lines, and the letter “i” indicates interlaced scanning). The video signal (525i) input from the input terminal 1 is supplied to the progressive scan conversion circuit 10,
0 generates a signal of a scanning line which is skipped by the interlaced scanning with respect to the input video signal of the interlaced scanning by motion adaptive interpolation processing, and doubles the input scanning line signal and the interpolated scanning line signal.
An output signal from the progressive scan conversion circuit 10 is supplied to a pixel number conversion circuit 20, and the pixel number conversion circuit 20 performs signal processing of reducing or enlarging in the horizontal direction or reducing or enlarging in the vertical direction the video signal of the progressive scan. . The signal from the pixel number conversion circuit 20 is output to the output terminal 2.

FIG. 10 is a block diagram showing the internal configuration of the progressive scan conversion circuit 10 of FIG. In FIG. 10, an input video signal is supplied to a motion detection circuit 11, an intra-field interpolation circuit 12, an inter-field interpolation circuit 13, and a speed-doubling circuit 15, respectively.

First, the motion detection circuit 11 detects video motion information from a difference signal component between one field or one frame, and supplies it to a mixing circuit 14.

In the intra-field interpolation circuit 12, a signal of an interpolated scanning line is generated from signals of scanning lines at vertical positions before and after the same field. FIG. 11 shows an example of the frequency characteristics of the interpolation filter used in the intra-field interpolation circuit 12.

The inter-field interpolation circuit 13 generates an interpolated scanning line signal from the scanning line signal at the same vertical position in the preceding and succeeding fields.

Output interpolation signals from the intra-field interpolation circuit 12 and the inter-field interpolation circuit 13 are supplied to a mixing circuit 14. As shown in FIG. 10, the mixing circuit 14 uses the motion coefficient k of the motion detection circuit 11 to calculate the motion adaptation from the signal output Xm of the interpolation scanning line of the intra-field interpolation circuit 12 and the output Xs of the inter-field interpolation circuit 13. Generates an interpolated signal Xa. The motion-adaptive interpolation signal Xa is represented by (Equation 1) Xa = k × Xm + (1−k) × Xs (0 ≦ k ≦ 1). Here, the motion coefficient k is “0” for a still image.
, And “1” in the moving image portion.

The interpolation signal and the input video signal of the mixing circuit 14 are supplied to a speed doubling circuit 15. The doubling circuit 15 alternately selects the interpolation signal and the input video signal of the mixing circuit 14 at a period twice as long as the horizontal scanning frequency, and sequentially scans 525 scanning lines sequentially converted from 525i (progressive scanning).
scanning) (hereinafter sometimes abbreviated as 525p. Here, the number “525” indicates the number of scanning lines, and the alphabet “p” indicates sequential scanning). The sequential scanning line signal of the speed doubling circuit 15 is supplied to the pixel number conversion circuit 20 of FIG.

Here, in the pixel number conversion circuit 20, 5
A sequential scanning line signal (525p) having 25 scanning lines is a sequential scanning line signal (78p) having 787.5 scanning lines.
An example of a case where the data is enlarged (3/2 times) to 7.5p) will be described with reference to FIGS.

FIG. 12 is a block diagram showing an internal configuration of the pixel number conversion circuit 20 of FIG. In addition, FIG.
FIG. 13D shows a frequency spectrum of a signal in each unit in FIG.

The pixel number conversion circuit 20 is supplied with a sequential scanning line signal (525p) having a frequency spectrum as shown in FIG. This sequential scanning line signal is supplied to the zero interpolation circuit 21. In the zero interpolation circuit 21, the sampling frequency fvs in the vertical direction = 525 [cph].
(Cycle per height), two data “0, 0” are inserted between the scanning lines, and the sampling frequency becomes 3f.
vs. data (FIG. 13B). Zero interpolation circuit 21
Is supplied to the V-LPF circuit 22. VL
In the PF circuit 22, the vertical frequency fvs / 2 to 3fvs
/ 2 data is sufficiently attenuated around the center to reduce DC harmonics and DC aliasing components as much as possible (FIG. 13).
(C)). The output signal of the V-LPF 22 is output to a thinning circuit 23.
Supplied to In the thinning circuit 23, the obtained data is sub-sampled every two data to obtain data of a sampling frequency fvs = 787.5 [cph] (FIG. 1).
3 (d)). The output signal of the thinning circuit 23 is output to the output terminal 2
Supplied to

In such a conventional video signal converter,
The progressive scan conversion circuit 10 can efficiently suppress the aliasing component of the still image and the aliasing component of the moving image by the motion adaptive interpolation, and can perform the progressive scan conversion without interference by interlace scanning. Further, the pixel number conversion circuit 20 at the subsequent stage can perform conversion into a predetermined format suitable for the number of pixels of the video display unit.

[0014]

However, in the conventional video signal conversion device, for example, when a moving image according to the NTSC system is input from the input terminal 1, the motion coefficient k from the motion detection circuit 11 becomes "1". And the motion adaptive interpolation signal Xa becomes Xa = Xm, and only the output signal of the intra-field interpolation circuit 12 is used as the interpolation signal in the mixing circuit 1.
4 is output. That is, the frequency characteristic at the time of moving image depends on the interpolation filter in the intra-field interpolation circuit 12, and the interpolation filter has a frequency characteristic as shown in FIG. In FIG. 11, for example, the pass band of the moving image up to the cutoff frequency at which the gain is reduced to 0.7 is approximately 90
[Cph]. The reproducible band of a moving image in the NTSC system is fvs / 4 = 131.25 [cph].
It is.

Therefore, 131.25 at the time of a moving image
Despite being able to transmit up to [cph] band,
It can be seen that in the conventional progressive scan conversion circuit 10, the pass band is reduced by about 30% as compared with the reproducible band of the moving image.

Further, even if the progressive scan line signal of the progressive scan conversion circuit 10 is enlarged and converted by the pixel number conversion circuit 20, the frequency characteristic at the time of the moving image is maintained, but no improvement is made.

From the above results, it can be seen that it is difficult for the conventional video signal conversion device to expand the pass band at the time of moving images. That is, when the pixel number conversion is performed after the sequential scan conversion, a sufficient pass band cannot be secured at the time of a moving image, so the image quality difference between a still image and a moving image becomes remarkable,
There is a problem that the image quality is deteriorated as a whole.

An object of the present invention is to solve the above-mentioned problem, and an object of the present invention is to provide a video signal conversion apparatus which reduces a difference in image quality when displaying a moving image and a still image and improves overall image quality. To provide.

[0019]

In order to achieve the above object, a first video signal converter according to the present invention receives an interlaced video signal and increases the number of pixels from the input video signal by a predetermined ratio. It is characterized by comprising a pixel number conversion unit for converting and outputting, and a progressive scanning conversion unit for converting an output signal of the pixel number conversion unit into a sequential scanning line signal adapted to the motion of an image.

In the first video signal conversion device, the progressive scan conversion unit includes a motion detection unit that detects a motion of an image based on an output signal of the pixel number conversion unit, and a motion detection unit based on an output signal of the pixel number conversion unit. An intra-field interpolation unit that generates an interpolated scanning line signal using at least a scanning line signal in the same field as the interpolated scanning line, and scans at least a field different from the interpolated scanning line based on an output signal of the pixel number conversion unit. The output signal of the intra-field interpolation unit and the output signal of the inter-field interpolation unit are adaptively mixed according to the motion according to the output signal of the motion detection unit and the inter-field interpolation unit that generates the interpolation scanning line signal using the line signal. It is preferable to include a mixing unit for performing the operation, and a speed-doubling unit that alternately switches the output signal of the mixing unit and the output signal of the pixel number conversion unit at a double speed to sequentially obtain scanning line signals.

According to the first video signal conversion device, the input video signal is enlarged by the pixel number conversion unit, the sampling frequency is increased, and then the progressive scan conversion unit sequentially scan-converts the input video signal, thereby achieving intra-field interpolation. The pass band of the section can be expanded, and the resolution of the moving image can be improved. Furthermore, by reducing the image quality difference between still images and moving images,
Overall image quality can be improved.

In order to achieve the above object, a second video signal conversion device according to the present invention comprises a pixel which receives an interlaced scanning video signal, converts the interlaced scanning video signal into a larger number of pixels than an input video signal at a predetermined ratio, and outputs the converted pixel number. A number conversion unit; and a progressive scan conversion unit that converts an output signal of the pixel number conversion unit into a progressive scan line signal adapted to the motion of an image from which isolated points have been removed.

In the second video signal conversion device, the progressive scan conversion unit includes a motion detection unit that detects a motion of an image based on an output signal of the pixel number conversion unit, and a motion isolated from the output signal of the motion detection unit. An isolated point removing unit for removing points,
Based on the output signal of the pixel number conversion unit, based on the output signal of the pixel number conversion unit, an intra-field interpolation unit that generates an interpolation scanning line signal using at least the scanning line signal in the same field as the interpolation scanning line An inter-field interpolation unit that generates an interpolated scanning line signal using at least a scanning line signal of a field different from the interpolated scanning line, and an output signal of an intra-field interpolation unit and an inter-field interpolation according to an output signal of an isolated point removing unit. A mixing unit that mixes the output signals of the units in accordance with the movement, and a speed-doubling unit that alternately switches the output signal of the mixing unit and the output signal of the pixel number conversion unit at double speed to sequentially obtain the scanning line signal. Is preferred.

It is preferable that the isolated point removing unit sets the maximum value of the motion data of at least the upper, lower, left, and right peripheral pixels surrounding the target pixel of the interpolation scanning line as the motion data of the target pixel.

According to the second video signal conversion device, after the number of scanning lines of the input video signal is increased by the pixel number conversion unit,
By generating an interpolated pixel based on the pixel information of the predetermined image area in the isolated point removing unit in the progressive scan conversion unit, for example, compared with a case where the number of pixels is converted after the progressive scan conversion,
Since the target pixel for removing the isolated point of the motion of the video is enlarged, it is possible to reduce the deterioration of the image quality when the motion detection unit erroneously detects the motion.

In order to achieve the above object, a third video signal conversion device according to the present invention comprises a pixel which receives an interlaced video signal, converts the interlaced video signal into a larger number of pixels than the input video signal at a predetermined ratio, and outputs the converted pixel number. A number conversion unit, a motion detection unit that detects image motion based on an output signal of the pixel number conversion unit, and a scanning line signal in at least the same field as the interpolation scanning line based on the output signal of the pixel number conversion unit. And an inter-field interpolating unit that generates an interpolated scanning line signal by using an inter-field interpolating unit that generates an interpolated scanning line signal using at least a scanning line signal of a field different from the interpolated scanning line based on an output signal of the pixel number conversion unit. An interpolation unit, a mixing unit that mixes the output signal of the intra-field interpolation unit and the output signal of the inter-field interpolation unit according to the motion in accordance with the output signal of the motion detection unit, and the output signal of the mixing unit and the pixel. A speed reduction unit for obtaining a progressive scanning line signal is switched alternately output signal of the converter unit at double speed, characterized by comprising a contour correcting unit that corrects the contour portion of the output signal of the speed reduction unit.

In the third video signal conversion device, it is preferable that the contour correction unit performs at least vertical contour correction on the output signal of the speed-doubling unit.

Further, the third video signal conversion device includes a motion information extension unit for generating, from the output signal of the motion detection unit, the output signal of the speed-doubling unit, the motion information of the scanning line having no corresponding motion information. It is preferable that the contour correction unit controls the correction amount according to the output signal of the motion information expansion unit.

According to the third video signal conversion device, the input video signal is enlarged by the pixel number conversion unit, the sampling frequency is increased, and then the sequential scan conversion unit performs the sequential scan conversion. By applying contour correction to the scanning lines sequentially in the section, the pass band of the intra-field interpolation section can be expanded, and a sufficient contour correction effect can be obtained even in a gentle contour portion, and the resolution of the moving image Can be improved.

[0030]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below with reference to the drawings.

(Embodiment 1) FIG. 1 is a block diagram showing a configuration example of a video signal conversion device according to Embodiment 1 of the present invention. The pixel number conversion circuit 20 and the progressive scan conversion circuit 10 in FIG. 1 have the same configurations as the circuits shown in FIGS. 12 and 10 described in the conventional example, respectively. In FIG. 1, a video signal (525i) of interlaced scanning of, for example, the NTSC system is input from an input terminal 1. The video signal (525i) input from the input terminal 1 is supplied to the pixel number conversion circuit 20, and the pixel number conversion circuit 20 performs horizontal reduction / expansion processing or vertical reduction / reduction on the interlaced input video signal. Perform enlargement processing. Pixel number conversion circuit 2
The output signal from 0 is supplied to the progressive scan conversion circuit 10,
The progressive scan conversion circuit 10 generates a signal of the scanning line that has been skipped by the interlaced scanning by motion adaptive interpolation processing, and doubles the output scanning line signal of the pixel number conversion circuit 20 and the interpolation scanning line signal. The signal from the progressive scan conversion circuit 10 is output to the output terminal 2.

Here, in the pixel number conversion circuit 20, 5
An interlaced scanning line signal having 25 scanning lines (525
The same figure as described in the conventional example, in a case where i) is vertically enlarged (3/2 times) converted into an interlaced scanning line signal (787.5i) having 787.5 scanning lines as an example. This will be described with reference to FIGS.

The pixel number conversion circuit 20 is supplied with an interlaced scanning line signal (525i) having a frequency spectrum as shown in FIG. This interlaced scanning line signal is supplied to the zero interpolation circuit 21. In the zero interpolation circuit 21, the vertical sampling frequency fvs = 525 [c]
ph], two data “0,
0 "is inserted to make the data have a sampling frequency of 3 fvs (FIG. 13B). The output signal of the zero interpolation circuit 21 is supplied to the V-LPF circuit 22. The V-LPF circuit 22
Then, the data of the vertical frequencies fvs / 2 to 3fvs / 2 are sufficiently attenuated at the center, and the harmonic components of DC and the aliasing component to DC are reduced as much as possible (FIG. 13C). V-LP
The output signal of F22 is supplied to the thinning circuit 23. In the thinning circuit 23, the obtained data is sub-sampled every two data, so that the sampling frequency fvs = 787.
The data is set to 5 [cph] (FIG. 13D). The output signal (787.5i) of the thinning circuit 23 is supplied to the sequential scan conversion circuit 10.

The interlaced scanning line signal (787.5i) from the pixel number conversion circuit 20 is supplied to the motion detection circuit 11 shown in FIG.
, The inter-field interpolation circuit 12, the inter-field interpolation circuit 13, and the speed-doubling circuit 15.

First, the motion detection circuit 11 detects video motion information based on a difference signal component between one field or one frame, and supplies it to the mixing circuit 14. The intra-field interpolation circuit 12 generates an interpolated scanning line signal from the scanning line signals at the vertical positions before and after the same field by using an interpolation filter having the frequency characteristics shown in FIG. Here, the coefficient value of the interpolation filter of the intra-field interpolation circuit 12 is the same as that of the conventional example. In addition, the inter-field interpolation circuit 13 generates an interpolated scanning line signal from the scanning line signal at the same vertical position in the preceding and succeeding fields.

Output interpolation signals from the intra-field interpolation circuit 12 and the inter-field interpolation circuit 13 are supplied to a mixing circuit 14. As shown in FIG. 13, the mixing circuit 14 uses the motion coefficient k of the motion detection circuit 11 to calculate the motion adaptation from the signal output Xm of the interpolation scanning line of the intra-field interpolation circuit 12 and the output Xs of the inter-field interpolation circuit 13. Generates an interpolated signal Xa. The motion-adaptive interpolation signal Xa is expressed by the above equation (1). Here, it is assumed that the motion coefficient k approaches “0” in a still image and approaches “1” in a moving image portion.

The interpolated scanning line signal of the mixing circuit 14 and the interlaced scanning line signal (787.5i) from the pixel number conversion circuit 20
Is supplied to the speed-doubling circuit 15. In the double speed circuit 15,
The interpolated scanning line signal from the mixing circuit 14 and the interlaced scanning line signal (787.5i) from the pixel number conversion circuit 20 are alternately selected at twice the cycle of the horizontal scanning frequency, and 787.5i.
, To 787.5p. The sequential scanning line signal of the speed doubling circuit 15 is supplied to the output terminal 2.

Here, in the configuration of the video signal converter shown in FIG. 1, for example, the input terminal 1 is connected to the NTSC system (525).
When the moving image i) is input, the motion coefficient k from the motion detection circuit 11 becomes “1”, and the motion adaptive interpolation signal Xa
Becomes Xa = Xm, and only the output signal of the intra-field interpolation circuit 12 is output from the mixing circuit 14 as an interpolation signal. That is, the frequency characteristics at the time of moving image depend on the interpolation filter of the intra-field interpolation circuit 12, and the interpolation filter has the frequency characteristics shown in FIG.

In FIG. 2, for example, the pass band of the moving image up to the cutoff frequency at which the gain drops to 0.7 is about 130
[Cph]. The reproducible band of a moving image in the NTSC system is fvs / 4 = 131.25 [cph].
It is. Therefore, it can be seen that the reproducible band of the moving image in the NTSC system is secured with almost no attenuation during the moving image. Further, as can be seen from comparison with FIG. 11 of the conventional example, the passband of the moving image is expanded even though the coefficients of the interpolation filter used in the processing at the time of the moving image are the same in the present embodiment and the conventional example. You can see that it is doing.

As described above, according to the present embodiment, for example, when an NTSC video signal (525i) is converted into an enlarged and sequentially scanned video signal (787.5p), the input video signal is converted to a pixel signal. 787.5i in the number conversion circuit 20
After increasing the sampling frequency and sequentially performing scan conversion to 787.5p by the progressive scan conversion circuit 10, the pass band of the intra-field interpolation circuit 12 can be expanded, and the resolution of the moving image can be reduced. Can be improved. Furthermore, the overall image quality can be improved by reducing the difference in image quality between the still image and the moving image.

(Embodiment 2) FIG. 3 is a block diagram showing a configuration example of a video signal conversion apparatus according to Embodiment 2 of the present invention. Note that the pixel number conversion circuit 20 in FIG. 3 has the same configuration as the circuit shown in FIG. 12 described in the conventional example and the first embodiment, and a description thereof will be omitted. Embodiment 2
The difference from the first embodiment is that the progressive scan conversion circuit 4 having an isolated point removal circuit 41 instead of the progressive scan conversion circuit 10 is used.
0 is provided.

FIG. 4 is a block diagram showing the internal configuration of the progressive scan conversion circuit 40 of FIG. Progressive scan conversion circuit 40
, An output signal from the motion detection circuit 11 is supplied to an isolated point removal circuit 41 for removing an isolated point of a video motion, and an output signal from the isolated point removal circuit 51 is supplied to the mixing circuit 14.
Supplied to

Next, the operation of the video signal converter configured as described above will be described. In FIG. 3, for example, a video signal (525i) of interlaced scanning of the NTSC system is input from an input terminal 1. This input video signal is
It is supplied to the pixel number conversion circuit 20. Pixel number conversion circuit 20
In the example, the interlaced scanning line signal (525i) having 525 scanning lines is vertically enlarged to the interlaced scanning line signal (787.5i) having 787.5 scanning lines (3/3).
2). The 787.5i interlaced scanning line signal enlarged and converted by the pixel number conversion circuit 20 is supplied to the sequential scanning conversion circuit 40.

In the progressive scan conversion circuit 40, the interlaced scan line signal (787.5i) from the pixel number conversion circuit 20
Are the motion detection circuit 11, the intra-field interpolation circuit 12, the inter-field interpolation circuit 13, and the speed-doubling circuit 15 shown in FIG.
And supplied to. The video motion information of the motion detection circuit 11 is supplied to the isolated point removal circuit 41.

The isolated point removal circuit 41 calculates the motion coefficient k of the target pixel to be interpolated based on the motion information of a plurality of pixels in a predetermined area centered on the target pixel.
The motion coefficient k of the target pixel is obtained. For example, when obtaining the motion information of the target pixel (P) to be interpolated as shown in FIG. 5, the isolated point removal circuit 41 uses, for example, three vertical (V) lines and three horizontal (H) video lines. By generating an interpolated pixel based on the pixel information in the pixel area, the motion detection circuit 11 is unlikely to use the motion information of a single pixel of the motion detection circuit 11 as the motion coefficient of the pixel of interest. In addition, it is possible to reduce the image quality deterioration that occurs when the motion detection is erroneous, for example, when a certain target pixel is determined to be a motion and still is determined to be still.

The motion coefficient k from the isolated point removing circuit 41 is
The signal is supplied to the mixing circuit 14, and the mixing circuit 14 uses the signal output Xm of the interpolation scanning line of the intra-field interpolation circuit 12 and the output Xs of the inter-field interpolation circuit 13 to perform motion adaptation as shown in Expression 1. An interpolated signal Xa is generated.

The interpolation scanning line signal Xa from the mixing circuit 14 and the scanning line signal (787.5i) from the pixel number conversion circuit 20
Is supplied to the speed-doubling circuit 15. The doubling circuit 15 alternately selects the interpolated scanning line signal Xa from the mixing circuit 15 and the scanning line signal (787.5i) from the pixel number conversion circuit 20 at a cycle twice the horizontal scanning frequency. 5i
, To 787.5p. The sequential scanning line signal of the speed doubling circuit 15 is supplied to the output terminal 2.

As described above, according to this embodiment, after the number of scanning lines is increased by enlarging and converting an input video signal by pixel number conversion, isolated points of video motion are removed. This increases the number of pixels of interest from which isolated points are removed, and can reduce image quality degradation due to erroneous video motion detection.

More specifically, for example, when converting an NTSC video signal (525i) into an enlarged and sequentially scanned video signal (787.5p), the pixel number conversion circuit 20 converts the input video signal into 787.5i. After increasing the number of scanning lines up to that point, the isolated point removing circuit 4 in the sequential scan conversion circuit 40
By generating the interpolated pixels based on the pixel information of the predetermined video area at 1, the isolated points of the motion of the video can be compared with the conventional example shown in FIG. Since the target pixel to be removed is enlarged, it is possible to reduce the image quality degradation in the event that the motion detection circuit 11 makes a wrong motion detection.

(Embodiment 3) FIG. 6 is a block diagram showing a configuration example of a video signal conversion apparatus according to Embodiment 3 of the present invention. The progressive scan conversion circuit 10 and the pixel number conversion circuit 20 of FIG. 6 have the same configurations as the circuits shown in FIGS. 10 and 12 described in the conventional example, respectively, and description thereof will be omitted.

The third embodiment is different from the first embodiment in that a motion detection circuit 11
And a point where a contour correction circuit 60 controlled on the output side of the progressive scan conversion circuit 10 according to the output signal of the motion information expansion circuit 70 is provided. is there.

The motion information expansion circuit 70 expands and generates, based on the motion coefficient k from the motion detection circuit 11, the motion information of the scanning line having no corresponding motion information with respect to the output signal of the speed-doubling circuit 15.

FIG. 7 is a block diagram showing the internal configuration of the contour correction circuit 60 of FIG.

In FIG. 7, the contour correction circuit 60 supplies a sequential scanning line signal (7) having a waveform as shown in FIG.
87.5p) is input and delayed by one horizontal scanning period (1H) one after another by the delay units 61a to 61d. The output signal from each delay unit is supplied to a maximum value detection circuit 62 and a minimum value detection circuit 63.

The maximum value detection circuit 62 detects the maximum value of the amplitude value from a plurality of scanning lines near the target scanning line (in the example of FIG. 7, two lines before and after the target scanning line output from the delay unit 61b). To detect. The minimum value detection circuit 63 detects the minimum value of the amplitude value from a plurality of scanning lines near the target scanning line.

In the average value circuit 65, the maximum value detection circuit 62
The average value is detected from the maximum value signal of the minimum value signal and the minimum value signal of the minimum value detection circuit 63.

The subtractor 66 subtracts the detection signal of the averaging circuit 65 from the target scanning line which is the output of the delay unit 61b.

In the gain adjusting circuit 67, the arithmetic processing circuit 6
For the output signal of No. 4, desired gain adjustment is performed according to the motion information extension signal 1 of the motion information extension circuit 70.

The adder 68 adds the output scanning line signal of the delay unit 61b and the output signal of the gain adjustment circuit 67.
The output signal of the adder 68 and the output signal of the maximum value detection circuit 62 are supplied to a non-linear processing circuit 69.

In the nonlinear processing circuit 69, the adder 68
Is used as a reference signal, the signal level does not become larger than the output signal of the maximum value detection circuit 62, and
By controlling so as not to be smaller than the output signal of the minimum value detection circuit 63, a video signal whose contour is corrected as shown in FIG. 8B is obtained and output from the output terminal 2.

As described above, according to the present embodiment, for example, the video signal (525i) of the NTSC system is expanded to 787.5i by the pixel number conversion circuit 20, the sampling frequency is increased, and then the sequential scanning is performed. 78 in conversion circuit 10
By performing the progressive scan conversion to 7.5p, the pass band of the intra-field interpolation circuit 12 in the progressive scan conversion circuit 10 can be expanded. Further, the contour correction circuit 60 sequentially performs the contour correction on the scanning lines according to the amount of motion of the video, so that a sufficient contour correction effect can be obtained even in a gentle contour portion, and the resolution of the moving image can be improved. And a difference in resolution between a still image and a moving image can be reduced.

In the first, second, and third embodiments, the input video signal is of the NTSC system (525i). However, the present invention is not limited to this. For example, an HDTV (1125i) having an interlaced scanning line structure is used. It is needless to say that the image quality of a moving image can be improved even if the video signal is

In the first, second, and third embodiments, the enlargement ratio of the pixel number conversion circuit 20 is set to 3/2 times. However, the present invention is not limited to this. Needless to say, the effect of improving the image quality can be obtained.

Further, in Embodiments 1, 2, and 3,
Although the enlargement direction of the pixel number conversion circuit 20 is set to the vertical direction, the effect of the present invention is not affected even when the pixel number conversion in the horizontal direction is performed at the same time.

[0065]

As described above, according to the present invention,
By improving the resolution of moving images, it is possible to reduce the difference in image quality between still images and moving images and improve overall image quality.
It has a special effect.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a configuration example of a video signal conversion device according to a first embodiment of the present invention.

FIG. 2 is a diagram illustrating frequency characteristics of an interpolation filter used in an intra-field interpolation circuit 12 included in the progressive scan conversion circuit 10 of FIG. 1;

FIG. 3 is a block diagram showing a configuration example of a video signal conversion device according to a second embodiment of the present invention.

FIG. 4 is a block diagram showing an internal configuration of a progressive scan conversion circuit 40 of FIG. 3;

FIG. 5 is a diagram schematically showing a target pixel and peripheral pixels for explaining the operation of the isolated point removing circuit 41 of FIG. 4;

FIG. 6 is a block diagram showing a configuration example of a video signal conversion device according to a third embodiment of the present invention.

7 is a block diagram showing an internal configuration of the contour correction circuit 60 in FIG.

8 is a waveform diagram showing an input signal (a) and an output signal (b) of the contour correction circuit 60 in FIG.

FIG. 9 is a block diagram showing a configuration of a conventional video signal conversion device.

FIG. 10 is a block diagram showing the internal configuration of the progressive scan conversion circuit 10 of FIG. 9;

11 is a diagram showing frequency characteristics of an interpolation filter used in the intra-field interpolation circuit 12 included in the progressive scan conversion circuit 10 of FIG.

FIG. 12 is a block diagram showing an internal configuration of a pixel number conversion circuit 20 of FIG. 9;

13 is a diagram showing a frequency spectrum of each part signal in the pixel number conversion circuit 20 of FIG. 9;

[Description of Signs] 1 video signal input terminal 2 video signal output terminal 10, 40 progressive scan conversion circuit 11 motion detection circuit 12 intra-field interpolation circuit 13 inter-field interpolation circuit 14 mixing circuit 15 double speed circuit 20 pixel number conversion circuit Reference Signs List 21 Zero interpolation circuit 22 V-LPF circuit 23 Thinning circuit 41 Isolated point removal circuit 60 Contour correction circuit 61a, 61b, 61c, 61d Delay unit 62 Maximum value detection circuit 63 Minimum value detection circuit 64 Arithmetic processing circuit 65 Average value circuit 66 Subtractor 67 Gain adjustment circuit 68 Adder 69 Nonlinear processing circuit 70 Motion information expansion circuit

 ──────────────────────────────────────────────────の Continuing on the front page (72) Inventor Tomohisa Tagami 1006 Kazuma Kadoma, Osaka Pref.Matsushita Electric Industrial Co., Ltd. F-term (reference) 5C063 AA01 AA11 BA04 BA08 BA09 BA12 CA01 CA05 5C082 AA02 BA12 BA27 BA41 BB03 BC16 CA21 CA32 CA55 CA81 CA84 MM10

Claims (8)

[Claims] 1. A pixel number conversion unit that receives an interlaced scanning video signal, converts the number of pixels into a larger number of pixels than an input video signal at a predetermined ratio, and outputs the number of pixels, and adapts an output signal of the pixel number conversion unit to image motion. And a progressive scan conversion unit for converting the signal into a progressive scan line signal. 2. The method according to claim 1, wherein the progressive scan conversion unit detects a motion of an image based on an output signal of the pixel count conversion unit, and at least an interpolation scan line based on an output signal of the pixel count conversion unit. And an intra-field interpolating unit that generates an interpolated scanning line signal using a scanning line signal in the same field.Based on an output signal of the pixel number conversion unit, at least a scanning line signal in a field different from the interpolated scanning line is used. An inter-field interpolator for generating an interpolated scanning line signal, and an output signal of the intra-field interpolator and an output signal of the inter-field interpolator are adaptively mixed according to the output signal of the motion detector. 2. The image processing apparatus according to claim 1, further comprising: a mixing unit; and a speed doubling unit that alternately switches an output signal of the mixing unit and an output signal of the pixel number conversion unit at a double speed to sequentially obtain a scanning line signal. Video signal converting apparatus. 3. A pixel number conversion unit that receives an interlaced scanning video signal, converts the number of pixels into a larger number of pixels than an input video signal at a predetermined ratio, and outputs the converted pixel number. And a progressive scan conversion unit for converting the scan signal into a progressive scan line signal adapted to the motion of an image. 4. The progressive scan conversion unit includes: a motion detection unit that detects a motion of an image based on an output signal of the pixel number conversion unit; and a motion detection unit that removes isolated points of motion from the output signal of the motion detection unit. An in-field interpolation unit that generates an interpolation scanning line signal using at least a scanning line signal in the same field as the interpolation scanning line based on an output signal of the pixel number conversion unit; An inter-field interpolation unit that generates an interpolation scanning line signal using a scanning line signal of at least a field different from the interpolation scanning line based on an output signal of the number conversion unit, and according to an output signal of the isolated point removal unit, A mixing unit that mixes the output signal of the intra-field interpolation unit and the output signal of the inter-field interpolation unit adaptively to motion, and alternately outputs the output signal of the mixing unit and the output signal of the pixel number conversion unit at a double speed. Video signal converting apparatus according to claim 3, characterized in that a speed reduction unit for obtaining a progressive scanning line signal Te Rikae. 5. The motion data of a pixel of interest, wherein the isolated point removing unit sets a maximum value of motion data of at least upper, lower, left, and right peripheral pixels surrounding the pixel of interest of the interpolation scanning line as motion data of the pixel of interest. Video signal converter. 6. A pixel number conversion unit which receives an interlaced scanning video signal, converts the number of pixels into a larger number of pixels than an input video signal at a predetermined ratio, and outputs the number of pixels, and a motion of an image based on an output signal of the pixel number conversion unit. A motion detection unit that detects, based on an output signal of the pixel number conversion unit, an intra-field interpolation unit that generates an interpolation scanning line signal using at least a scanning line signal in the same field as the interpolation scanning line; An inter-field interpolation unit that generates an interpolation scanning line signal using a scanning line signal of a field different from at least the interpolation scanning line based on an output signal of the pixel number conversion unit, and an output signal of the motion detection unit, A mixing unit that mixes the output signal of the intra-field interpolation unit and the output signal of the inter-field interpolation unit adaptively to motion, and outputs the output signal of the mixing unit and the output signal of the pixel number conversion unit at double speed. A speed reduction unit for obtaining a progressive scanning line signal one another switching, the video signal converting apparatus characterized by comprising a contour correcting unit that corrects the contour portion of the output signal of the speed reduction unit. 7. The video signal conversion device according to claim 6, wherein the contour correction unit performs at least vertical contour correction on an output signal of the speed-doubling unit. 8. The video signal conversion device according to claim 1, further comprising: a motion information extension unit configured to generate, from the output signal of the motion detection unit, the output signal of the speed doubling unit, the motion information of the scanning line having no corresponding motion information. The video signal conversion device, wherein the contour correction unit controls a correction amount according to an output signal of the motion information expansion unit.