JP2002199250A - Television receiver provided with ghost reduction function and television reception method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a television receiver provided with a ghost reduction function that can set the number of arithmetic times required from start of ghost reduction(GR) processing until a resulting image is displayed to an optimum state sufficiently corresponding to a radio wave state by each channel and a ghost occurrence state or the like without the need for man-hours. SOLUTION: An S/N detection section 16 that detects an S/N level of a signal subjected to GR processing is provided to an output side of a GR processing section 13 and a control section 18 acquires information denoting the S/N level by the S/N detection section 16 upon the request of GR processing. Then the control section 18 reads the number of first-time GCR(Ghost Cancellation Reference) analysis times that is conducted until a filter coefficient of the GR processing section 13 depending on the S/N level is first set from a control information storage section 22 and sets the read the number of first-time GCR analysis times to an arithmetic section 13d of the GCR processing section 13, Then the arithmetic section 13d repeats the analysis/arithmetic processing of a GCR signal by a set number of times to set the filter coefficient to a digital filter section 13b.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement in a television receiver having a ghost reduction function for reducing ghosts and a method thereof.

[0002]

2. Description of the Related Art As is well known, an apparatus for receiving a broadcasted television signal and performing processing for image display, such as a television receiver, a VTR (Video Tape Recorder) or a television tuner. In
It is a major problem to improve reception failure due to ghosts, and various ghost cancellers have been conventionally developed.

In particular, EDTV (Extended Definition Te)
levision) broadcasting and IDTV (Improved Definition Tele)
vision) In broadcasting or the like, a GCR, which is a reference signal for ghost cancellation, is used during a vertical blanking period of a television signal.
A signal is inserted and transmitted, and a ghost reduction processing unit provided on the receiving side performs ghost reduction processing based on the received GCR signal.

In the ghost reduction processing section, there are two types of ghost removal algorithms: a feedback control type and a feedforward control type. Is detected, and the ghost component is removed by calculating the tap coefficient of the ghost removal filter based on the detection result.

[0005] For this reason, immediately after the ghost reduction processing is started, the ghost reduction processing unit cannot perform sufficient ghost reduction processing because the number of calculations is insufficient, and rather, the ghost reduction processing unit does not operate. In some cases, a false ghost which does not exist originally is generated and added to a television signal.

However, such false ghosts are reduced along with the original ghosts as the number of calculations performed by the ghost reduction processing unit is increased with the lapse of time. In some cases, every time a ghost reduction process is performed, a false ghost is often added, which causes a problem that an image becomes hard to see.

Further, the ghost reduction processing in the ghost reduction processing section is performed stepwise with the passage of time. Therefore, depending on the state of occurrence of ghost, the image may change several times during the reduction processing. For some viewers, such a change in the image may be considered unsightly.

For this reason, in recent years, in order to prevent the occurrence of false ghosts as described above and to prevent the image from being unsightly due to the gradual ghost reduction processing or the like, a certain period of time has elapsed since the start of the ghost reduction processing. It is common practice to display a normal image that has not been subjected to ghost reduction processing and not to display an image that has been subjected to ghost reduction processing.

However, if the waiting time from the start of the ghost reduction process to the display of the image subjected to the ghost reduction process is set too long,
Since it takes too long for the image after the ghost reduction to be displayed, a problem arises in that the viewer has to watch the ghosted image for an unnecessarily long time.

Therefore, the present inventor has disclosed in Japanese Patent Application No. 2000-094.
No. 681, the number of analysis / calculation processes until the filter coefficient of the ghost reduction processing unit is set for the first time is
We have proposed a television receiver that can be set for each channel so that the waiting time until an image subjected to ghost reduction processing is displayed can be arbitrarily selected for each channel.

[0011]

However, in such a television receiver, the number of analysis / calculation processes required before switching to the ghost-reduced video is determined repeatedly by the viewer for each channel and manually set. In particular, if the number of channels is large, the setting takes a lot of time, which is very inconvenient.

Accordingly, an object of the present invention is to reduce the number of analysis and calculation processes required from the start of ghost reduction processing to the display of the image by using the radio wave condition and ghost occurrence condition for each channel without requiring any human intervention. It is an object of the present invention to provide a television receiver and a television receiving method having a ghost reduction function that can be set to an optimal state sufficiently corresponding to the above.

[0013]

SUMMARY OF THE INVENTION A television receiver having a ghost reduction function according to the present invention sets a coefficient by repeating calculations from a ghost removal reference signal included in a received television signal. Along with performing a ghost reduction process on the television signal based on the set coefficient, and when the coefficient is not set, a ghost reduction processing unit that outputs the television signal as it is, and a ghost reduction processing unit is provided before or after the ghost reduction processing unit, A first characteristic detection unit for detecting a signal characteristic from an input signal or an output signal of the ghost reduction processing unit, and a ghost reduction process in a state where the ghost reduction process is requested according to a detection result by the first characteristic detection unit. Determine the number of calculations for coefficient setting in the By its number of operations is obtained by such a control unit to perform the setting of coefficients in the ghost reduction processing unit.

In this configuration, a characteristic detecting unit for detecting a signal characteristic from an input signal or an output signal of the ghost reduction processing unit is provided, and a viewer performs a request operation of the ghost reduction processing. Then, the detection result by the characteristic detection unit is supplied to the control unit, and the control unit obtains the number of calculations for setting the coefficient in the ghost reduction processing unit according to the detection result. In other words, in accordance with the ghost reduction process request, the control unit sufficiently determines the number of calculations required from the start of the ghost reduction process for each channel to the display of the image in accordance with the radio wave condition, ghost occurrence status, and the like of each channel. Automatically set to the optimal state.

Therefore, the viewer only needs to perform a ghost reduction process request operation on the control unit, watch the video of each channel, judge the occurrence of ghost, and set the number of calculations so as to obtain an optimal video. This eliminates the need to perform any operation, thereby greatly reducing the operational burden of the ghost reduction process.

According to the present invention, the ghost reduction processing section is provided before or after the first characteristic detection section, or at a stage opposite to the stage where the first characteristic detection section is provided in the ghost reduction processing section. The apparatus further includes a second characteristic detecting unit that detects a signal characteristic different from the first characteristic detecting unit from the input signal or the output signal, and the control unit is configured to perform the first and second signal processing when the ghost reduction process is requested. The number of calculations for setting a coefficient in the ghost reduction processing unit is determined according to a detection result by at least one of the characteristic detection units, and the coefficient is set in the ghost reduction processing unit based on the number of calculations. I do.

According to this configuration, the second characteristic detecting section is provided in addition to the first characteristic detecting section, so that the signal characteristics different from each other from the input signal or output signal of the ghost reduction processing section by each characteristic detecting section. The number of calculations required from the start of the ghost reduction process to the display of the image according to the usage status and the television signal to be handled is determined by the radio wave condition and ghost occurrence status for each channel. Can be automatically set to an optimal state sufficiently corresponding to the above-mentioned conditions, and the number of calculations for coefficient setting in the ghost reduction processing unit can be obtained with high accuracy, thereby improving the reliability of the ghost reduction processing. be able to.

Further, in the present invention, a table is stored in which the number of calculations for setting a coefficient in the ghost reduction processing section is associated with a plurality of detection levels by at least one of the first and second characteristic detection sections. A control unit configured to control the detection level by at least one of the first and second characteristic detection units with reference to the table stored in the storage unit when the ghost reduction process is requested. The ghost reduction processing unit is configured to set a coefficient in accordance with the number of operations corresponding to the number of operations.

According to this configuration, the information indicating the number of operations is read from the table stored in the storage unit in accordance with the detection level of the characteristic detection unit, so that the coefficient is set for the ghost reduction processing unit from the detection level each time. The appropriate number of calculations can be set by a simple process without calculating the number of calculations.

[0020]

Embodiments of the present invention will be described below in detail with reference to the drawings.

(First Embodiment) FIG. 1 is a circuit block diagram of a television receiver having a ghost reduction function according to a first embodiment of the present invention.

In FIG. 1, a television broadcast wave received by an antenna 11 is supplied to a tuning unit 12, and a television signal of a desired channel is tuned. The television signal selected by the tuning unit 12 is supplied to a ghost reduction (hereinafter, referred to as GR) processing unit 13.

The GR processing unit 13 converts the analog television signal output from the channel selection unit 12 into a digital signal.
A D (Analog / Digital) conversion unit 13a, and a digital filter unit 13 for performing ghost reduction processing on the digital television signal output from the A / D conversion unit 13a.
b and D / D which converts the digital television signal output from the digital filter section 13b into an analog signal and outputs the analog signal.
An A (Digital / Analog) converter 13c and a GCR signal superimposed on a coefficient to be set in the digital filter 13b based on external control in a vertical blanking period of the television signal output from the tuner 12. And an operation unit 13d for analyzing and calculating from.

The output signal of the GR processing unit 13 is supplied to a Y (luminance signal) / C (color signal) separation unit 14.

The Y / C separation section 14 separates the input television signal into a luminance signal Y and a chrominance signal C,
It is output to the C / D processing unit 15. The V / C / D processing unit 15 converts the input luminance signal Y and color signal C into a form in which an image can be displayed by a CPT (Color Picture Tube) unit 17 at the subsequent stage and sends the converted signal to the S / N detection unit 16. Output. S
The / N detection unit 16 outputs S / V from the output of the V / C / D processing unit 15
/ N level, that is, the signal quality, and notifies the control unit 18 of the detection result.
e Tube) section 17. Here, the television signal is displayed as an image.

Here, the ON / OFF setting of the GR processing unit 13 is performed by the control unit 18. This control unit 1
Reference numeral 8 controls on / off setting of the GR processing unit 13 based on operation information from the key operation unit 19 or operation information transmitted from the remote controller 20 and received by the reception unit 21.

The control unit 18 includes a control information storage unit 22
And the position information storage unit 23 are connected to each other. Of these, the control information storage unit 22 stores, for example, S / N
Level 1 indicates that the first GCR analysis is performed once, and S / N level 2 indicates that the S / N level by the S / N detection unit 16 and the S / N level are digital after the GR processing is started. Until the coefficient is set to the filter unit 13b for the first time, the number of times the calculation unit 13d performs the analysis and calculation processing is stored in association with the number of times.

The position information storage unit 23 stores the position, the channel information, and the information on the GR process in association with each other. The information on the GR processing includes “auto” and “off” for setting the GR processing unit 13 to the off state.

The channel information for each position and G
The information regarding the R processing can be arbitrarily input and set by the viewer by operating the key operation unit 19 or the remote controller 20.

Here, the control unit 18 sets the GR processing unit 13 to ON while viewing the operation information for switching the channel to “30” or the channel “30” from the key operation unit 19 or the remote controller 20. When the operation information to be received is received, the storage contents of the position information storage unit 23 are first checked to recognize that the information regarding the GR processing corresponding to the channel “30” is “auto”, and the S / N detection unit 16 To obtain the S / N level detected from the output of the V / C / D processing unit 15,
Here, when it is recognized that the level is “level 2”, the contents stored in the control information storage unit 22 are checked and the first GC
It recognizes that the number of R analyzes is two.

For this reason, the control unit 18 sets the number of initial GCR analyzes to “2” for the calculation unit 13d. Then, the calculation unit 13d performs the analysis and calculation processing of the GCR signal in two.
The coefficient is set repeatedly, and the digital filter unit 13b
To supply.

In this case, the digital filter section 13b
Until the coefficient set by the calculation unit 13d is supplied, the input television signal is kept in a non-output state, that is, a signal that does not perform any processing is output. However, after the coefficient is supplied, A ghost-reduced signal is output.

The operation unit 13d repeats the analysis and operation processing of the GCR signal thereafter, updates the coefficients to be given to the digital filter unit 13b, and operates to optimize the coefficients.

Next, the operation of the control unit 18 will be described. Key operation unit 19 or remote controller 20
When the operation information requesting the GR process is received, the control unit 18 starts the control process as shown in FIG.

When the control process is started, the control unit 18 first searches the position information storage unit 23 for information on the GR process corresponding to the designated channel (step ST1), and determines whether or not the process is set to auto. Is performed (step ST2).

If auto is set, the control unit 18 determines whether or not information indicating the S / N level has been input from the S / N detection unit 16 (step ST).
3) The process of step ST3 is repeatedly executed until an input is made.

When the information indicating the S / N level is input, the control unit 18 searches the control information storage unit 22 for information indicating the number of times of the first GCR analysis according to the S / N level (step ST4). ), The number of times of the first GCR analysis searched is set in the calculation unit 13d (step ST5).

Thereafter, the controller 18 repeatedly executes the processing of steps ST3 to ST5 until the channel is switched or the power switch is turned off.

When the information on the GR process is received in the process of step ST2 as "OFF", that is, operation information for switching the channel to "2", the control unit 18 causes the calculation unit 13d to calculate the coefficient. Is controlled so as not to exist (step ST6). Therefore, the digital filter unit 1
3b is set to a state in which the input television signal is output as it is because the coefficient is not set by the operation unit 13d, that is, is set to an off state, and is controlled so that the ghost reduction processing is not performed.

As described above, in the first embodiment, G
An S / N detector 16 for detecting the S / N level of the signal subjected to the GR processing is provided on the output side of the R processor 13, that is, at the subsequent stage of the V / C / D processor 15. Part 1
9 or the remote controller 20 is used to perform an operation for requesting GR processing. Then, information indicating the S / N level by the S / N detection unit 16 is supplied to the control unit 18, and the control unit 18 supplies a GR corresponding to the S / N level.
Initial G until the filter coefficient of the processing unit 13 is set for the first time
The number of times of CR analysis is read from the control information storage unit 22.

Therefore, according to the first embodiment, in response to the operation for requesting the GR processing, the control unit 18 sets the waiting time from the start of the GR processing for each channel to the display of the image as the waiting time for each channel. Automatically set to an optimal state sufficiently corresponding to the radio wave condition, the ghost occurrence condition, and the like. For this reason, the viewer simply performs a GR operation request operation on the control unit 18 using the key operation unit 19 or the remote controller 20 to view the video of each channel, determine the ghost occurrence state, and It is not necessary to perform any operation for setting the number of operations so that the image becomes a proper image, and thus the operational burden due to GR processing can be greatly reduced. Also, since no viewer is involved during the GR processing, the time required for the GR processing is reduced, and further, the occurrence of an operation error is prevented, so that accurate and highly reliable GR processing can be performed.

In the first embodiment, if the GR processing section 13 applies GR processing to a television signal to which no ghost is added, the quality of the television signal will be degraded. Therefore, the information indicating “OFF” is stored in the position information storage unit 23 in association with the channel to which the ghost is not added, and when the channel to which the ghost is not added is selected, the processing of the GR processing unit 13 is performed. I'm trying to stop.

(Second Embodiment) FIG. 3 is a circuit block diagram of a television receiver having a ghost reduction function according to a second embodiment of the present invention. 3, the same parts as those in FIG. 1 are denoted by the same reference numerals, and detailed description will be omitted.

That is, in this television receiver, the modulation degree detecting section 24 is interposed between the channel selecting section 12 and the GR processing section 13, and the V / C / D processing section 15 and the S / N detecting section 16 are connected to each other. The sag detection unit 25 is interposed between them. Among them, the modulation degree detecting section 24 detects, for example, the degree of amplitude modulation of the television signal selected by the tuning section 12, and notifies the control section 18 of the detection result. The sag detection unit 25 uses V / C
A periodic change in the DC level of the output of the / D processing unit 15 is detected, and this detection result is notified to the control unit 18.

The control unit 18 has a control information storage unit 26
Is connected to the control information storage unit 26. For example, the modulation level detection unit 24 and the sag level are set so that the first level GCR analysis is performed once for the condition level 1 and the first GCR analysis is performed four times for the condition level 2. The calculation unit 1 is provided between the condition level of the detection unit 25 and the S / N detection unit 16 and the initial setting of the coefficient in the digital filter unit 13b after the GR process is started.
3d stores the number of times of performing the analysis / calculation processing in association with each other.

In such a configuration, the control unit 18
From the key operation unit 19 or the remote controller 20,
When the operation information for switching the channel to “30” is received, first, the storage contents of the position information storage unit 23 are checked to recognize that the information regarding the GR processing corresponding to the channel “30” is “auto”.

If the control unit 18 recognizes that the auto mode is set, the control unit 18 determines whether information indicating the detection level has been input from the S / N detection unit 16, the modulation degree detection unit 24, and the sag detection unit 25. Is determined. And S / N
If information indicating the detection level is input from the detection unit 16, the modulation degree detection unit 24, and the sag detection unit 25, the control unit 18
Determines a condition level from these detection levels according to a predetermined condition. The predetermined condition includes a method of obtaining an average value of the total level of the S / N detection unit 16, the modulation degree detection unit 24, and the sag detection unit 25, and a priority set in advance by a viewer according to a use situation. S / N detector 1
6, a method of selecting from the detection levels of the modulation degree detecting section 24 and the sag detecting section 25, and the like.

Subsequently, the control unit 18 searches the control information storage unit 26 for information indicating the number of initial GCR analyzes according to the determined condition level, and sets the searched initial GCR analysis number in the calculation unit 13d. Then, the operation unit 13d calculates G
The coefficient is set by repeating the analysis and calculation processing of the CR signal a set number of times, and the coefficient is supplied to the digital filter unit 13b.

In this case, the digital filter section 13b
Until the coefficient set by the calculation unit 13d is supplied, the input television signal is kept in a non-output state, that is, a signal that does not perform any processing is output. However, after the coefficient is supplied, A ghost-reduced signal is output.

The arithmetic unit 13d operates to repeat the analysis and arithmetic processing of the GCR signal thereafter to update the coefficient given to the digital filter unit 13b and optimize the coefficient.

As described above, according to the second embodiment, the modulation degree detecting section 24 and the sag detecting section 25 are provided in addition to the S / N detecting section 16 so as to perform the processing before the GR processing is performed or Since different signal characteristics are detected by the S / N detection unit 16, the modulation degree detection unit 24, and the sag detection unit 25 from the signal after the signal is applied, the GR is changed according to the use situation and the television signal to be handled. The waiting time from the start of the processing to the display of the image can be automatically set to an optimal state sufficiently corresponding to the radio wave condition and the ghost occurrence condition for each channel. Initial G for coefficient setting in processing unit 13
The number of times of CR analysis can be obtained with higher accuracy than in the first embodiment, and the reliability of GR processing can be improved.

In the second embodiment, for example, S
If the detection accuracy of the / N detection unit 16 is deteriorated, if the optimum detection result is selected from the detection results of the other modulation degree detection unit 24 and the sag detection unit 25, the television set handled as the whole television receiver It is possible to maintain the characteristic detection accuracy of the John signal.

(Other Embodiments) The present invention is not limited to the scope of each of the above embodiments. For example, S /
In addition to the N detection unit, modulation degree detection unit and sag detection unit, by providing a characteristic detection unit that detects the frequency of out-of-synchronization, the degree of synchronization loss, the electric field strength, and other degrees, the number of initial GCR analysis is more suitable. It becomes possible to be.

In the first and second embodiments,
An example has been described in which the detection level and the number of initial GCR analyzes are stored in the control information storage unit in association with each other, but the number of initial GCR analyzes according to the detection level may be calculated each time in the control unit. .

In the first embodiment, the GR
Although the example in which the S / N detection unit 16 is provided after the processing unit 13 has been described, the S / N detection unit 16 may be provided before the GR processing unit 13. This is advantageous in terms of response speed.

In the first and second embodiments,
As the information on the GR processing stored in the position information storage unit, “auto” and “off” have been described as examples, but “manual” may be set depending on the channel. This is advantageous when manual adjustment is required for some channels.

In addition, the configuration of the television receiver, the type of television signal to be handled, the function and control procedure of the control unit, and the storage contents of the control information storage unit and the position information storage unit also deviate from the gist of the present invention. Various modifications can be made without departing from the scope.

[0058]

As described in detail above, according to the present invention,
Set the number of analysis and calculation processes required from the start of the ghost reduction process to the display of the image in an optimal state that fully responds to the radio wave condition and ghost occurrence status of each channel without requiring human intervention A television receiver and a television receiving method having a possible ghost reduction function can be provided.

[Brief description of the drawings]

FIG. 1 is a circuit block diagram for explaining a first embodiment of a television receiver having a ghost reduction function according to the present invention.

FIG. 2 is a flowchart illustrating a processing operation of a control unit according to the embodiment.

FIG. 3 is a circuit block diagram for explaining a second embodiment of a television receiver having a ghost reduction function according to the present invention.

[Explanation of symbols]

 11 antenna, 12 channel selection unit, 13 GR processing unit, 14 Y / C separation unit, 15 V / C / D processing unit, 16 S / N detection unit, 17 CPT unit, 18 control unit Reference numeral 19: key operation unit, 20: remote controller, 21: reception unit, 22: control information storage unit, 23: position information storage unit, 24: modulation degree detection unit, 25: sag detection unit, 13a: A / D conversion Unit, 13b: digital filter unit, 13c: D / A conversion unit, 13d: arithmetic unit.

Claims (7)

[Claims] 1. A coefficient is set by repeatedly performing an operation from a ghost removal reference signal included in a received television signal, and a ghost reduction process is performed on the television signal based on the set coefficient. When the coefficient is not set, a ghost reduction processing unit that outputs the television signal as it is, and a signal characteristic is detected from an input signal or an output signal of the ghost reduction processing unit, which is provided before or after the ghost reduction processing unit. A first characteristic detection unit, and in a state where ghost reduction processing is requested, the number of calculations for setting a coefficient in the ghost reduction processing unit is determined in accordance with a detection result by the first characteristic detection unit. Coefficient in the ghost reduction processing unit according to the number of times Television receiver having a ghost reduction function, characterized by comprising a control unit to perform the setting. 2. The ghost reduction processing unit, wherein the ghost reduction processing unit is provided at a stage before or after the first characteristic detection unit, or at a stage opposite to a stage provided with the first characteristic detection unit in the ghost reduction processing unit. The apparatus further includes a second characteristic detection unit that detects a signal characteristic different from the first characteristic detection unit from an input signal or an output signal, wherein the control unit is configured to perform the ghost reduction processing in a state where the ghost reduction processing is requested. The number of calculations for setting a coefficient in the ghost reduction processing unit is determined according to a detection result by at least one of the second characteristic detection units, and the coefficient is set in the ghost reduction processing unit based on the number of calculations. The television receiver having a ghost reduction function according to claim 1, wherein: 3. A storage for storing a table in which the number of calculations for setting a coefficient in the ghost reduction processing unit is associated with a plurality of detection levels by at least one of the first and second characteristic detection units. A control unit configured to detect the ghost reduction process by at least one of the first and second characteristic detection units with reference to a table stored in the storage unit in a state where the ghost reduction process is requested. 3. The television receiver having a ghost reduction function according to claim 1, wherein the number of calculations corresponding to the level is read, and the coefficient in the ghost reduction processing unit is set based on the number of calculations. 4. The table includes information indicating that calculation for coefficient setting is not performed, or information for performing calculation for coefficient setting in a mode preset according to a channel. A television receiver having a ghost reduction function according to claim 3. 5. The first and second characteristic detectors include at least signal quality of a received television signal, periodic fluctuation of a DC level, modulation degree, frequency of loss of synchronization, degree of synchronization loss, electric field strength. The television receiver having a ghost reduction function according to claim 1, wherein the television receiver detects one of the following. 6. A coefficient is set by repeating calculation from a ghost removal reference signal included in a received television signal, and a ghost reduction process is performed on the television signal based on the set coefficient. If the coefficient is not set, a first step of outputting the television signal as it is, a second step of detecting signal characteristics from an input signal or an output signal in the first step, and a ghost reduction process are required. In the state, the number of calculations for setting the coefficient in the first step is determined according to the detection result in the second step, and the third step of setting the coefficient in the first step is performed based on the number of calculations. And a television receiving method. 7. A coefficient is set by repeating calculation from a ghost removal reference signal included in a received television signal, and a ghost reduction process is performed on the television signal based on the set coefficient. If the coefficient is not set, a first step of outputting the television signal as it is, a second step of detecting a signal characteristic from an input signal or an output signal of the first step, and an input of the first step A third step of detecting a signal characteristic different from the second step from the signal or the output signal, and a detection result of the second step or a detection of the third step when ghost reduction processing is required. The number of calculations for setting the coefficient in the first step is determined according to the result, and the number of calculations is used in the first step. A fourth step of setting a coefficient in the television receiving method.