Patent Application
20080151993
This application is based upon and claims the benefit of priority from Japanese Patent Application No. 2006-350016, filed Dec. 26, 2006, the entire contents of which are incorporated herein by reference.
1. Field
One embodiment of the invention relates to a video signal processing apparatus and a video signal processing method for reducing a video signal, and a broadcasting receiving apparatus using the video signal processing apparatus.
2. Description of the Related Art
In recent years, as to television broadcasting, not only analog broadcasting but also satellite wave and ground wave broadcasting is widely provided and watched. In such digital broadcasting, a broadcasting signal which is received and output by a digital tuner is output as, for example, an MPEG file. For this reason, after this signal is decoded by an MPEG decoder, the decoded signal is used as a video signal. A number of techniques which relate to methods for treating video signals of such digital broadcasting are known.
Patent Document 1 (Jpn. Pat. Appln. KOKAI Publication No. 2004-180248) discloses a technique for determining whether a coding distortion eliminating process is necessary and carrying out block filtration only if necessary in an image coding distortion eliminating method.
The conventional technique in the Patent Document 1 shows a coding distortion in the MPEG decoder, but does not disclose a technique for executing a video process on a video signal from the MPEG decoder and an uncoded video signal in different manners.
A general architecture that implements the various feature of the invention will now be described with reference to the drawings. The drawings and the associated descriptions are provided to illustrate embodiments of the invention and not to limit the scope of the invention.
Various embodiments according to the invention will be described hereinafter with reference to the accompanying drawings. In general, according to one embodiment of the invention, a video signal processing apparatus comprising: a determining section which receives a type signal representing whether a video signal is an uncoded video signal or a video signal obtained by decoding a coded digital signal, determines a first threshold for determining a density change of the video signal when the type signal represents the uncoded video signal, and determines a second threshold smaller than the first threshold when the type signal represents the video signal obtained by decoding the coded digital signal; a detecting section which receives the video signal and detects a density change which is smaller than the first threshold or the second threshold determined by the determining section, by using the threshold; and a subtracting section which, when the detecting section detects the density change, subtracts the density change component.
One embodiment of the present invention provides a video signal processing apparatus and a video signal processing method which execute different video processes on an uncoded video signal and a decoded video signal from a digital tuner, and a broadcasting receiving apparatus.
One embodiment for achieving the object is a video signal processing apparatus comprising:
a determining section (11, 14, 17) which receives a type signal (d2) representing whether a video signal (d1) is an uncoded video signal or a video signal obtained by decoding a coded digital signal, determines a first threshold (Tha, Thc) for determining a density change of the video signal when the type signal represents the uncoded video signal, and determines a second threshold (Thb, Thd, Thf) smaller than the first threshold when the type signal represents the video signal obtained by decoding the coded digital signal;
a detecting section (12, 15, 18) which receives the video signal and detects a density change which is smaller than the first threshold or the second threshold determined by the determining section, by using the threshold; and
a subtracting section (13, 16, 19) which, when the detecting section detects the density change, subtracts the density change component.
As a result, since a noise of a video signal coded by a decoder is reduced by the decoder, the noise which is not more than a small threshold Tha is corrected to a small level. Since noise remains in the uncoded video signal, this noise which is not more than a large threshold Thb is corrected to a large level.
The embodiment of the present invention will be described in detail below with reference to the drawings.
<One Example of Video Processing Apparatus According to One Embodiment of the Present Invention>
The video processing apparatus according to one embodiment of the present invention will be described in detail below with reference to the drawings.
The video processing apparatus according to one embodiment of the present invention is a video processing apparatus 142 including a horizontal-direction coring section 21 shown in
As shown in
As shown in
As shown in
The time axis noise eliminating section 26 included in the video processing apparatus 142 has, as shown in
Detailed operations of the horizontal coring section 21, the vertical coring section 22, the horizontal enhancer section 23, the vertical enhancer section 24 and the time axis noise eliminating section 26 will be described later with reference to the flowcharts.
(Constitution and Operation of Broadcasting Receiving Apparatus)
A constitution and an operation of a broadcasting receiving apparatus as one example of the apparatus to which the video processing apparatus 142 is applied will be described with reference to
The broadcasting receiving apparatus 100 in
The broadcasting receiving apparatus 100 has an MPEG decoder section 116, a separating section 117, a memory section 135 and an electronic program information processing section 136. The memory section 135 suitably records video information from the tuner sections. The electronic program information processing section 136 acquires electronic program information from a broadcasting signal so as to display the information on a screen. These sections are connected to the control section 130 via the data bus. An output from the selector section 119 is connected to a display section 121, and is supplied to an external apparatus via an interface section 122 for communication with the external apparatus.
The broadcasting receiving apparatus 100 is connected to the control section 130 via the data bus, and has an operating section 132 which receives user's operations and operations of a remote controller R. The remote controller R enables the operations approximately equivalent to those of the operating section 132 provided to the main body of the broadcasting receiving apparatus 100, namely, enables various settings such as the operations of the tuners.
In the broadcasting receiving apparatus 100, a broadcasting signal is input from an reception antenna into the tuners 112 and 113, where a channel selection is made. The selected video/audio signal is decoded by the MPEG decoder section 116 so as to be supplied to the video processing section 118. The video processing section 118 has an IP converting section 141, an image quality processing section 142, a scaling section 143 and a γ correcting section 144. The IP converting section 141 converts an interlace signal into a progressive signal. The image quality processing section 142 executes a coring process and an enhancing process detailed in
These input signals are managed by the control section 130, and are switched into signals to be input into the video processing section 118. An operation signal from the remote controller R is supplied to the control section 130 via the operating section 132 in order to make the channel selection and input conversion. As a result, the MPEG decoder section 116 and the video processing section 118 are controlled. The video signal processed by the video processing section 118 is displayed on the display section 121 via the selector section 119. The audio signal is supplied to a speaker, not shown.
(Coring Processes in Horizontal and Vertical Directions)
The coring processes in the horizontal and vertical directions in the image quality processing section 142 in
That is to say, the functions of the horizontal coring section 21 and the vertical coring section 22 can be realized by synthesizing circuit configurations having the following functions or can be suitably realized by a microcomputer and programs.
The horizontal coring section 21 shown in
Horizontal Coring Process
As shown in the flowchart of
The uncoded video signal includes not only the video signal output from the analog tuner section 113 but also an analog video signal supplied from a video apparatus such as a video recorder analog-connected from the outside, and a video signal of an uncompressed type external DVD player digital-connected.
The originally coded video signal includes not only the video signal output from the digital tuner section 112 and decoded by the decoder but also a video signal obtained by decoding a coded video signal supplied from the external video apparatus by a decoder.
That is to say, when the threshold determining section 11 determines that the video signal d1 is the uncoded video signal based on the type signal d2, it supplies a threshold signal d3 to the horizontal-direction detecting section 12. When the horizontal-direction detecting section 12 detects a density change in the horizontal direction smaller than a threshold Tha from the video signal d1 based on the threshold Tha (>Thb) by means of a threshold signal d3, it supplies a detection signal d4 to the subtracting section 13 (step S12).
The subtracting section 13 subtracts a density change component detected based on the detection signal d4, so as to eliminate a noise component from the video. A correcting amount at this time is determined by the subtracting section 13 based on the type signal d2. When the type signal d2 shows that the video signal d1 is an uncoded video signal, the subtracting process is executed on the video signal according to the correcting amount A (step S13).
As a result, when the video signal d1 is an uncoded video signal, a larger quantity of noise remains in comparison with an original digital video. For this reason, the subtracting process is executed on the noise detected by means of the larger threshold Thb according to the large correcting amount A (>correcting amount B).
Similarly, in Step S11, when the threshold determining section 11 determines that the video signal d1 is an originally coded video signal based on the type signal d2, it supplies a threshold signal d3 to the horizontal-direction detecting section 12. When the horizontal-direction detecting section 12 detects a density change in the horizontal direction smaller than the threshold Thb from the video signal d1 based on the threshold Thb (<Tha) by means of the threshold signal d3, it supplies a detection signal d4 to the subtracting section 13 (step S14).
The subtracting section 13 subtracts the density change component detected based on the detection signal d4, so as to eliminate a noise component from the video. The correcting amount at this time is determined by the subtracting section 13 based on the type signal d2. When the type signal d2 shows that the video signal d1 is an original coded video signal, the subtracting process is executed on the video signal according to the correcting amount B (<correcting amount A) (step S15).
As a result, when the video signal d1 is the originally coded video signal, noise has already been eliminated by the decoder section 116 to a certain extent at the time of DA conversion. For this reason, this video signal includes comparatively less noise than noise in the uncoded video signal, and thus the noise detected based on the small threshold Thb is subtracted according to the small correcting amount B (<correcting amount A).
In this embodiment, a discrimination is made whether the video signal is an originally coded video signal, a video signal with less noise DA-converted by the decoder section 116 or an uncoded video signal with comparatively larger noise. The threshold for detecting noise (density change) and the correcting amount of the subtracting process are changed. As a result, a suitable image quality process can be executed according to characteristics of video signals.
Vertical Coring Process
Since the process from step S21 to step S25 shown in the flowchart of
A relationship: Tha>Thb holds for the threshold at the time of the horizontal coring process, but a relationship: Thc>Thd holds for the threshold of the vertical coring process. A relationship: correcting amount A>correcting amount B holds in the horizontal coring process, but a relationship: correcting amount C>correcting amount D holds in the vertical coring process.
In the case of the vertical coring process, a discrimination is made whether the video signal is an originally coded video signal, a video signal with less noise DA-converted by the decoder section 116 or an uncoded video signal with comparatively large noise. The threshold for detecting noise (density change) and the correcting amount of the subtracting process are changed, thereby enabling the suitable image quality process according to characteristics of video signals.
Time Axis Noise Eliminating Process
Since the process from step S31 to step S35 shown in the flowchart of
The relationship: Tha>Thb holds for the threshold at the time of the horizontal coring process, but a relationship: The>Thf holds for the threshold in the time axis noise eliminating process. The relationship: correcting amount A>correcting amount B holds in the horizontal coring process, but a relationship: correcting amount E>correcting amount F holds in the time axis noise eliminating process.
In the case of the time axis noise eliminating process, a discrimination is made whether the video signal is an originally coded video signal, a video signal with less noise DA-converted by the decoder section 116, or an uncoded video signal with comparatively large noise. The threshold for detecting noise (density change) and the correcting amount of the subtracting process are changed, thereby enabling the suitable image quality process according to characteristics of the video signals.
In the case where the video signals recorded in the memory section 135 are subject to the coring process and the noise eliminating process, it is desirable that the control section 130 generates and manages type information at the time of recording. That is to say, it is desirable that type information which represents that the video signal is an uncoded video signal or an originally coded video signal is attached to management information for the recording process of the video signals generated by the control section 130 so as to be managed in a memory area or the like.
When the video signals are managed in such a manner, the control section 130 generates the type signal d2 at the time of reproduction based on type information which represents whether the stored video signal is an uncoded video signal or an originally coded video signal so as to supply the type signal d2 to the coring sections 21 and 22. As a result, the video signal recorded in the memory section 135 can be processed according to the type of the video signal similarly to a real-time video signal.
A person skilled in the art can realize the present invention by the above various embodiments, and easily conceives of various modified examples of these embodiments, and can apply the present invention to various embodiments without inventive ability. The present invention, therefore, covers a wide range which does not conflict with the disclosed principle and new characteristics, and thus is not limited to the above embodiments.
While certain embodiments of the inventions have been described, these embodiments have been presented by way of example only, and are not intended to limit the scope of the inventions. Indeed, the novel methods and systems described herein may be embodied in a variety of other forms; furthermore, various omissions, substitutions and changes in the form of the methods and systems described herein may be made without departing from the spirit of the inventions. The accompanying claims and their equivalents are intended to cover such forms or modifications as would fall within the scope and spirit of the inventions.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2006-350016 | Dec 2006 | JP | national |
