JP4019503B2 - Video signal processing apparatus and video signal processing method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a video signal processing apparatus and a video signal processing method suitable for use, for example, when a standard television signal is subjected to double speed conversion processing. More specifically, for example, a phenomenon in which the luminance of a part of an image becomes excessively high is prevented by emphasizing a high frequency component in the vertical direction when a standard television signal is subjected to double speed conversion processing.
[0002]
[Prior art]
For example, as a double-speed conversion processing device that converts a standard television signal of 525 interlaced NTSC system or 625 interlaced PAL system into a 1050/1250 interlaced double-speed signal, the input images are classified according to the pattern. A high-precision double-speed conversion processing device has been proposed (Japanese Patent Laid-Open No. 7-75066) that replaces a double-speed pattern that produces a high-definition image.
[0003]
By using such a double speed conversion processing device, the image quality of a natural image taken by a camera, for example, can be remarkably improved. However, such an apparatus is provided with processing for emphasizing high-frequency components in the vertical direction, particularly for the purpose of improving the image quality in the vertical direction. In this case, there is no problem with the above-described natural image. However, for an artificial image such as a telop superimposed on the natural image, for example, the luminance of a part of the image becomes excessively high. Is.
[0004]
That is, for example, in a telop superimposed on a natural image, the vertical frequency at the edge portion becomes extremely high. Therefore, when the high frequency component in the vertical direction is emphasized in such an image, the luminance level of the edge portion becomes excessively high and becomes conspicuous. For this reason, image quality degradation such as so-called line flicker and defocus due to the characteristics of a cathode ray tube for displaying an image occurs.
[0005]
In addition to the above-mentioned telop, such image quality degradation also occurs when, for example, a menu screen for adjusting the receiver is displayed superimposed on a natural image. The enhancement of high-frequency components in the vertical direction of the image is not limited to the video signal processing that performs the high-precision double-speed conversion as described above, but is also performed in double-speed conversion by so-called vertical interpolation and general vertical enhancement. Even in such a case, the above-described image quality deterioration occurs.
[0006]
[Problems to be solved by the invention]
The present application has been made in view of the above points, and the problem to be solved is that, in the conventional apparatus, for example, a high frequency band in the vertical direction is used when a standard television signal is subjected to double speed conversion processing. The enhancement of the component causes image quality degradation such as so-called line flicker and defocus.
[0007]
[Means for Solving the Problems]
Therefore, in the present invention, the image-processed signal, the original signal, and the reference level are compared, and these signals are switched and extracted according to the comparison result. Luminance levels do not become excessively high for images such as telops, and image quality deterioration such as so-called line flicker and defocus can be prevented.
[0008]
DETAILED DESCRIPTION OF THE INVENTION
That is, the present invention is a video signal processing apparatus and method in combination enhancement of the high-frequency component of the vertical direction, and the processing time equal to the time delay in the enhancement of the video signal before performing the enhancement processing, enhancement processing selecting a signal delayed signal is compared with the a signal and an arbitrary reference level delay, when large and delayed signal than any signal enhancement processing signal is delayed and any reference level is greater than the reference level When the emphasized signal is larger than both the delayed signal and an arbitrary reference level and the delayed signal is smaller than the reference level, the reference level is selected. Otherwise, the emphasized signal is selected. Is.
[0009]
【Example】
The present invention will be described below with reference to the accompanying drawings. FIG. 1 is a block diagram showing a configuration of an example of a standard television signal double speed conversion processing apparatus to which a video signal processing apparatus and a video signal processing method according to the present invention are applied. is there.
[0010]
In FIG. 1, for example, a standard television signal serving as an original signal is supplied to the input terminal 1. The standard television signal from the input terminal 1 is supplied to a double speed conversion circuit 2 that performs high-precision conversion as described above, for example. In this example, the double speed conversion circuit 2 outputs the double speed signals 1 and 2 of the two scanning lines subjected to the double speed conversion simultaneously on the original time axis.
[0011]
Further, a standard television signal from the input terminal 1 is supplied to a delay circuit 3 having a delay time equal to the processing time in the double speed conversion circuit 2 described above. Furthermore, a generator 4 for generating a reference level is provided. The reference level generated by the generating unit 4 may be 100% luminance level, 90% luminance level, 80% luminance level, and the like, and these can be switched.
[0012]
The reference level from the generating unit 4 and the signal from the delay circuit 3 and the double speed signals 1 and 2 from the double speed conversion circuit 2 are supplied to the comparators 5 and 6, respectively. In these comparators 5 and 6, the double speed signal from the double speed conversion circuit 2 is compared with the delay signal from the delay circuit 3 and the reference level from the generation unit 4, respectively, and discrimination results 1 and 2 are formed. The
[0013]
That is, in these comparators 5 and 6, for example, (1) when the double speed signal is larger than both the delayed signal and the reference level, and the delayed signal is larger than the reference level,
(2) When the double speed signal is larger than both the delayed signal and the reference level, and the delayed signal is smaller than the reference level,
(3) A determination is made at other times.
[0014]
At the same time, in these comparators 5 and 6, based on the above discrimination results, the difference signal of [double speed signal-delay signal] when [1] and [double speed signal-reference level] when [2] respectively. 1 and 2 are formed. The difference signals 1 and 2 and the above-described discrimination results 1 and 2 are supplied to the output data control units 7 and 8, respectively. Further, the double speed signals 1 and 2 of the two scanning lines from the double speed conversion circuit 2 are supplied to the output data controllers 7 and 8, respectively.
[0015]
These output data control units 7 and 8 perform control to subtract the difference signals 1 and 2 from the double speed signals 1 and 2 when the determination results 1 and 2 are (1) or (2). Is called. When the above-described discrimination results 1 and 2 are (3), control for taking out the double speed signals 1 and 2 as they are is performed.
[0016]
Further, the signal output from these output data control units 7 and 8 is a time axis for converting, for example, the double speed signals 1 and 2 as shown in A and B of FIG. 2 into the final scanning signal as shown in C of FIG. It is supplied to the conversion circuit 9. Then, the converted final scanning signal is taken out to the output terminal 10.
[0017]
In this apparatus, when the double speed signal is larger than both the delayed signal and the reference level and the delayed signal is larger than the reference level ((1)), the difference signal of [double speed signal-delayed signal] is subtracted from the double speed signal. As a result, a signal output corresponding to the delay signal is taken out from the output data control units 7 and 8 as shown in A of FIG.
Double speed signal-[Double speed signal-Delay signal] = Delay signal
When the double speed signal is larger than both the delayed signal and the reference level and the delayed signal is smaller than the reference level ((2)), the difference signal of [double speed signal−reference level] is subtracted from the double speed signal. As a result, the signal output corresponding to the reference level is taken out from the output data control units 7 and 8 as shown in FIG.
Double speed signal-[Double speed signal-Reference level] = Reference level
Further, at times other than the above ((3)), the double speed signal is taken out from the output data control sections 7 and 8 as it is as shown in C of FIG.
[0020]
That is, in this apparatus, the state of (3) usually occurs with the highest probability, and is the case where the excessive speed component is not included in the double speed signals 1 and 2 from the double speed conversion circuit 2. In this case, the double speed signals 1 and 2 from the double speed conversion circuit 2 are taken out from the output data control sections 7 and 8 as they are.
[0021]
Next, state (2) is when the luminance level of the double speed signal is excessively high even though the level of the original signal is low. In this case, if the double speed signal is output as it is, there is a high possibility that a bad effect due to high luminance occurs. For example, if the output is replaced with the level of the original signal as in the process (1), the effect of the double speed conversion process on the natural image may not be sufficiently exhibited. Therefore, in this case, output is performed by replacing the intermediate level with the reference level.
[0022]
Further, the state (1) is a case where the level of the double speed signal is larger than that of the original signal and has sufficiently reached the high luminance level due to the enhancement effect, but the original signal is also at a relatively high luminance level. Also in this case, if the double speed signal is output as it is, there is a high possibility that a bad effect due to high luminance occurs. Further, for example, when the output is replaced with the reference level as in the process (2), a level lower than the original signal is output, resulting in a signal deteriorated from the original signal.
[0023]
Therefore, in this case, the double-speed signal is replaced with the luminance level of the original signal and output, thereby preventing the deterioration of the signal and reducing the adverse effects due to the high luminance.
[0024]
Therefore, in this apparatus, the image processed signal, the original signal, and the reference level are compared, and these signals are switched and extracted according to the comparison result. Does not become excessively high, and image quality degradation such as so-called line flicker and defocusing can be prevented.
[0025]
As a result, the conventional apparatus has a problem that image quality degradation such as so-called line flicker and defocusing occurs due to enhancement of a high frequency component in the vertical direction, which is performed when a standard television signal is subjected to double speed conversion processing. According to the present invention, these problems can be easily solved.
[0026]
The present invention is not limited to the case of performing the video signal processing for performing the high-precision double speed conversion as described above. For example, the double speed conversion by so-called vertical interpolation using a line memory or the vertical high speed in general vertical enhancement. This also has the same effect in emphasizing band components.
[0027]
Thus according to the video signal processing apparatus and a video signal processing method described above, a video signal processing apparatus and method in combination enhancement of the high-frequency component of the vertical direction, at enhancement of the video signal before performing the enhancement processing processing and time delay equal to the time, compares the signal and the delayed enhancement processing signal and the arbitrary reference level, larger and delayed signal than any signal enhancement processing signal is delayed and any reference level When the signal is larger than the reference level, the delayed signal is selected. When the emphasized signal is larger than both the delayed signal and any reference level and the delayed signal is smaller than the reference level, the reference level is selected. by selecting a highlighted processed signal, prevents such brightness level becomes excessively high relative to the image such as the telop time, so-called One in which it is possible to prevent the deterioration of image quality such as a line flicker and defocus.
[0028]
Note that the present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the spirit of the present invention.
[0029]
【The invention's effect】
Therefore, according to the first and third aspects of the present invention, the image-processed signal, the original signal, and the reference level are compared, and these signals are switched and extracted according to the comparison result. The luminance level does not become excessively high for images such as telops, and image quality deterioration such as so-called line flicker and defocus can be prevented.
[0030]
As a result, the conventional apparatus has a problem that image quality degradation such as so-called line flicker and defocusing occurs due to enhancement of a high frequency component in the vertical direction, which is performed when a standard television signal is subjected to double speed conversion processing. According to the present invention, these problems can be easily solved.
[Brief description of the drawings]
FIG. 1 is a configuration diagram of an example of a video signal processing apparatus to which the present invention is applied.
FIG. 2 is a diagram for explaining the operation;
FIG. 3 is a diagram for explaining that;
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Input terminal, 2 ... Double speed conversion circuit, 3 ... Delay circuit, 4 ... Reference level generation part, 5, 6 ... Comparator, 7, 8 ... Output data control part, 9 ... Time axis conversion circuit, 10 ... Output Terminal

Claims (4)

A video signal processing apparatus including an image processing circuit that emphasizes a high frequency component in a vertical direction,
Providing delay means having a delay time equal to the processing time in the image processing circuit,
Supplying the delay means with the video signal before the enhancement;
Compare the signal from the image processing circuit and the signal from the delay means with an arbitrary reference level,
When the signal from the image processing circuit is greater than either the signal from the delay means and any reference level and the signal from the delay means is greater than the reference level, the signal from the delay means is selected,
When the signal from the image processing circuit is larger than both the signal from the delay means and an arbitrary reference level and the signal from the delay means is smaller than the reference level, the reference level is selected,
In other cases, a signal from the image processing circuit is selected . The video signal processing apparatus according to claim 1 , wherein
When the signal from the image processing circuit is larger than both the signal from the delay means and an arbitrary reference level, and the signal from the delay means is larger than the reference level [signal from the image processing circuit-delay (Signal from means)
Form the difference signal of
When the signal from the image processing circuit is larger than both the signal from the delay means and an arbitrary reference level and the signal from the delay means is smaller than the reference level, [signal from the image processing circuit−the reference level〕
Form the difference signal of
The video signal processing apparatus characterized in that the extracted signal is formed by calculating the difference signal and the signal from the image processing circuit. A video signal processing method that uses high-frequency component enhancement processing in the vertical direction,
The video signal before performing the enhancement process is delayed by a time equal to the processing time in the enhancement process,
Comparing the enhanced signal with the delayed signal and an arbitrary reference level;
Selecting the delayed signal when the emphasized signal is greater than either the delayed signal or any reference level and the delayed signal is greater than the reference level;
Selecting the reference level when the enhanced signal is greater than any of the delayed signal and any reference level and the delayed signal is less than the reference level;
In other cases, the emphasized signal is selected.
And a video signal processing method. The video signal processing method according to claim 3, wherein
When the enhanced signal is greater than either the delayed signal or any reference level and the delayed signal is greater than the reference level
[The enhanced signal-the delayed signal]
Form the difference signal of
When the emphasized signal is greater than either the delayed signal or any reference level and the delayed signal is less than the reference level
[The enhanced signal-the reference level]
Form the difference signal of
The extracted signal is formed by calculating the difference signal and the emphasized signal.
And a video signal processing method.

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