JP2003304506A - Video signal processing apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve a task of a conventional up-convert system applied to a video signal for various video signal processing apparatuses that has required enhanced resolution. <P>SOLUTION: After up-conversion by linear interpolation, harmonics are produced by nonlinear processing, only the high frequency components is extracted, the gain is adjusted by a limiter and a frame difference, and an output of a gain adjustment 16 is added to the video signal. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a video signal processing device for up-converting a video signal.

[0002]

2. Description of the Related Art Conventionally, a video signal processing device has been disclosed in Japanese Patent Laid-Open No.
The one described in Japanese Patent No. 8838 is known.

A conventional video signal processing apparatus has, for example, a vertical 4
A video signal of 80 lines and 780 dots horizontally (hereinafter referred to as "48
"0P video signal"), 720 lines vertically, 1 horizontally
Video signal of 280 dots (hereinafter referred to as "720P video signal"
Indicated) was up-converted to increase the number of pixels by linear interpolation. It is assumed that the horizontal spectral intensity of the input 480P video signal is shown in FIG. In FIG. 2, f480 is half the horizontal sampling frequency of the 480P video signal, and f720 is 72.
The frequency is half the horizontal sampling frequency of the 0P video signal. This 480P video signal is linearly interpolated,
The spectral intensity after up-converting to the 0P video signal is the same as the spectral intensity of the original 480P video signal. That is, the resolution cannot be improved by the conventional up-conversion by linear interpolation.

[0004]

In this video signal processing device, it is required to improve the resolution during up-conversion.

An object of the present invention is to improve the resolution when up-converting a video signal.

[0006]

In order to solve this problem, the present invention provides a non-linear processing means for generating a harmonic by non-linearly converting an original video signal, and a high frequency component of a signal from the non-linear processing means. A high-pass filter means for passing the signal, a gain adjusting means for adjusting the gain of the signal from the high-pass filter means, and a control means for controlling the non-linear processing means or the gain adjusting means according to the original video signal. It is a thing.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to FIGS.

(Embodiment 1) FIG. 1 shows an embodiment of a video signal processing apparatus of the present invention. In FIG.
Oversampling for converting an 80P video signal into a 720P video signal by linear interpolation, 12 is high-frequency emphasis for emphasizing high-frequency components of the 720P video signal from oversampling 11, and 14 is 7 from oversampling 11.
Non-linear signal processing for non-linear conversion of 20P video signal, 15
Is a high-pass filter that extracts the high-frequency component of the signal from the nonlinear signal processing 14 and limits it at a certain signal level,
Reference numeral 16 is a gain adjustment for adjusting the gain of the signal from the high-pass filter 15, and 17 is a non-linear signal processing 1 which detects a motion from the spectrum intensity of a signal band of a 720P video signal from the oversampling 11 or a frame difference.
An image determination controller that controls the non-linear function 4 and the gain of the gain adjustment 16, and an adder 13 that adds the signal from the high-frequency emphasis 12 and the signal from the gain adjustment 16.

The operation of the video signal processing apparatus configured as described above will be described below.

4 input to oversampling 11
It is assumed that the horizontal spectrum intensity of the 80P video signal is shown in FIG. An example of the waveform is shown in FIG. Since the oversampling 11 converts into a 720P video signal by linear interpolation, the 720P output from the oversampling 11
The spectrum intensity of the video signal remains as in FIG. However, since the sampling frequency is different, the sampling time is different even if the waveform is the same, and an example of the waveform is shown in FIG. 11.
FIG. 3 shows the spectrum intensity of the 720P video signal from the oversampling 11 after the high-frequency component is emphasized by the high-frequency emphasis 12.

An example of the waveform is shown in FIG. The non-linear signal processing 14 has two input / output characteristics having a saturation characteristic as shown in FIG. 6 (function 61 and function 62), and the switching of the function 61 and the function 62 is controlled by the image determination controller 17. ing. Due to the non-linear processing of the function 61 or the function 62, a harmonic wave is generated and a frequency component of f480 [Hz] or higher is generated. The signal of the non-linear signal processing 14 is input to the high pass filter 15.

FIG. 8 is a block diagram of the inside of the high-pass filter 15. In FIG. 8, the high-pass filter 81 extracts harmonics of f480 [Hz] or higher. The harmonics extracted by the high-pass filter 81 are limited by the limiter 82 to a value below a certain value Th82. As a result, the spectrum intensity of the output signal of the high pass filter 15 is as shown in FIG.

An example of the waveform is shown in FIG. The harmonics from the high pass filter 15 are gain-adjusted by the gain adjustment 16 and are limited to a fixed value. In the gain adjustment at this time, the gain is adjusted by multiplying the signal from the high-pass filter 15 by the signal from the video determination controller 17. The gain-adjusted signal and the signal from the high-frequency emphasis 12 are added by the adder 13 and output as a video signal. As a result, the spectrum intensity of this video signal output is as shown in FIG. 5, and an example of the waveform is shown in FIG.
become. Therefore, it can be seen that the frequency components in the high frequency range are larger than those of the 720P video signal that is generated by linearly interpolating the 480P video signal.

Further, the operation of the image determination controller 17 will be described. The image determination controller performs switching control of the nonlinear function of the nonlinear signal processing 14 and gain adjustment of the gain adjustment 16. Switching the nonlinear function is
F480 / of video signal from oversampling 11
Analyze the spectrum intensity in the mid range around 2 [Hz] and the high range near f480 [Hz]. If the mid range spectrum intensity is higher than the high range, the function 61, the mid range spectrum intensity is higher than the high range. If it is weak, it is switched to the function 62.

The gain adjustment will be described with reference to FIG.
FIG. 7 is a block diagram of only the gain adjusting unit of the image determination controller 17. 71 is f480 / 2 [Hz] to f
Spectral intensity detection for detecting the spectral intensity around 480 [Hz], 72 is a limiter for limiting the input signal by a certain value Th72, 73 is a multiplier, 74 is a frame differentiator for calculating a difference between frames, and 75 is an input signal. The value Th
If 74 or more, 1 is output, and if less than Th74, 0
Is a slicer that outputs.

Next, this operation will be described. The basic operation is to control the gain proportional to the intensity detected by the spectrum intensity detector 71. However, with this method, there are problems such as ringing at the edge portion of the video signal and fluctuations of a moving portion.
Since the output of the spectrum intensity detection 71 becomes strong at the edge portion, the limiter 72 limits the value. Further, a moving part is detected by the frame difference unit 74 and the slicer 75, and 0 is output at a part determined to be moving, and 1 is output at a part not moving.

Therefore, by the multiplier 73, the signal from the limiter 72 becomes the gain as it is in the non-moving portion, and the gain becomes 0 in the moving portion, so that the output of the gain adjustment 16 also becomes 0, and the harmonic wave becomes Not added.

With these configurations, since the harmonics are added to the 720P video signal formed by linearly interpolating the 480P video signal, the harmful effects due to the addition of the harmonics can be suppressed, so that the high-frequency components with less harmful effects are supplemented. , The resolution is improved.

In the above description, the frequency component in the horizontal direction has been described, but the frequency component in the vertical direction can be similarly implemented.

Further, in the above description, as an example of the method of suppressing the harmful effect, the limiter and the frame difference at two locations are shown. However, if the harmful pattern is detected and the addition of the harmonic is limited, the same applies. It is feasible.

In the above description, a function having a saturation characteristic is used as the non-linear function for generating the harmonic, but the non-linear function such as the diode characteristic 92 and the square characteristic 91 as shown in FIG. If so, any function can be similarly implemented.

[0022]

As described above, according to the present invention, a harmonic is generated from a video signal, and the gain of the harmonic is limited by using a limiter or a frame difference and added to the video signal.
The remarkable effect that the resolution can be improved while suppressing the adverse effects due to the addition of harmonics is obtained.

[Brief description of drawings]

FIG. 1 is a block diagram of a video signal processing device according to an embodiment of the present invention.

FIG. 2 is a graph showing horizontal spectral intensity of an input video signal according to an embodiment of the present invention.

FIG. 3 is a graph showing horizontal spectrum intensity after high-frequency emphasis according to an embodiment of the present invention.

FIG. 4 is a graph showing the horizontal spectral intensity of harmonics according to an embodiment of the present invention.

FIG. 5 is a graph showing the spectral intensity in the horizontal direction after adding harmonics according to an embodiment of the present invention.

FIG. 6 is a graph showing a non-linear function according to an embodiment of the present invention.

7 is an internal block diagram of only a gain adjusting unit of the image determination control of FIG. 1 according to an embodiment of the present invention.

8 is an internal block diagram of high pass filter 15 of FIG. 1 according to one embodiment of the present invention.

FIG. 9 is a diagram showing an example of a non-linear function capable of obtaining the same effect as that of the embodiment of the present invention.

FIG. 10 is a graph showing a waveform of an input video signal according to an embodiment of the present invention.

FIG. 11 is a graph showing a waveform after oversampling according to an embodiment of the present invention.

FIG. 12 is a graph showing a waveform after high-frequency emphasis according to the embodiment of the present invention.

FIG. 13 is a graph showing a waveform of a harmonic wave according to the embodiment of the present invention.

FIG. 14 is a graph showing a waveform after adding a harmonic according to an embodiment of the present invention.

[Explanation of symbols]

11 Oversampling 12 High range emphasis 13 adder 14 Non-linear signal processing 15 High pass filter 16 Gain adjustment 17 Video judgment controller 61 Non-linear function 62 Non-linear function 71 Spectral intensity detection 72 Limiter 73 Multiplier 74 frame differencer 75 slicer 81 High pass filter 82 Limiter 91 Non-linear function example (square characteristic) 92 Non-linear function example (diode characteristics)

   ─────────────────────────────────────────────────── ─── Continued front page    F-term (reference) 5C021 PA17 PA33 PA53 PA66 PA99                       RA01 RB04 RC06 XB02 ZA11                 5C063 AB01 AB03 AC01 AC05 BA01                       BA12 CA07 CA23

Claims (9)

[Claims] 1. A video signal processing apparatus for enhancing the definition of a video signal by adding a harmonic wave generated from the video signal to the original video signal, wherein the nonlinear conversion of the original video signal generates a harmonic Processing means, high-pass filter means for passing the high-pass component of the signal from the non-linear processing means, gain adjusting means for adjusting the gain of the signal from the high-pass filter means, the non-linear processing means or the A video signal processing device, comprising: a control means for controlling a gain adjusting means according to an original video signal. 2. The video signal processing apparatus according to claim 1, wherein the high-pass filter means has a limiter for limiting the output value. 3. The video signal processing apparatus according to claim 1, wherein the non-linear processing means has a plurality of non-linear functions, and the plurality of non-linear functions are switched by the control means. 4. The control means has a mid-range component detecting means for detecting a mid-range component of the video signal, and a limiter means for limiting a signal from the mid-range component detecting means. The described video signal processing device. 5. The video signal processing apparatus according to claim 1, wherein the control means has pattern detection. 6. The video signal processing device according to claim 4, wherein the pattern detection by the control means is edge detection. 7. The video signal processing device according to claim 1, wherein the control means detects the motion based on a difference between the frames. 8. Oversampling means for oversampling a video signal, high-frequency component generating means for generating a high-frequency component by the video signal processing device according to claim 1, and oversampling the signal from the oversampling means. A video signal processing device comprising: a signal from the means and an adding means for adding the signal from the high frequency component generating means. 9. The control means in the high frequency component generation means limits the signal from the signal component detection means for detecting a signal component corresponding to the high frequency component of the signal before oversampling and the signal from the signal component detection means. 9. The video signal processing device according to claim 8, further comprising limiter means for performing the above.