JP2624321B2 - Television signal processor - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a television signal processing device.

2. Description of the Related Art In recent years, in order to realize higher image quality of a television image, an incoming television signal is subjected to different signal processing for a still image and a different signal for a moving image, and the motion of the image is detected. The signal subjected to the image signal processing and the signal subjected to the moving image signal processing are mixed in accordance with the motion amount of the image.

However, when the motion detection is incomplete, for example, when a slightly moving image is determined and processed as a still image, image quality deteriorates, such as halftone dots or multi-line interference occurring on the screen.

With respect to such deterioration, by applying a temporal filter process, it is possible to make the image quality deterioration due to erroneous determination of motion detection inconspicuous and to improve the image quality of the television image. Kimiaki Jitsu as a well-known television signal processor for processing
There is a technique disclosed in Japanese Patent Application Laid-Open No. 62-46386, and a configuration example thereof is shown in FIG.

The television signal processor 6 shown in FIG. 4 converts the signal supplied to the signal input terminal 601 into an LPF 602 and the LPF
H with cut-off frequency crossover with 602 cut-off frequency
The PF 603 separates a desired low frequency component and a high frequency component, and the high frequency component and the frame memory 604 are separated.
The signal having the minimum absolute value is selected and output by the minimum absolute value selection circuit 606 out of the high frequency components delayed by one frame and the average high frequency component obtained by adding and adding both of them by the adder 605. Then, the low frequency component and the output of the minimum absolute value selection circuit 606 are synthesized in a synthesis circuit 607 and supplied to a signal output terminal 608.

For example, if a still object starts to move and the motion detection is erroneously determined to be a still image, halftone dots will appear on the screen and image quality will deteriorate unless temporal filter processing is performed. Since the halftone dot has a large favorable frequency component, in the above-described television signal processing device 6, the minimum absolute value selection circuit 606 selects the high frequency component without halftone dot one frame before to reduce the halftone dot. Can be.

As described above, the television signal processing device 6 cuts the high frequency components when the motion detection is incomplete and the high frequency components greatly change between frames, so that the image quality deterioration due to erroneous determination of the motion detection is not noticeable. (Blurring). Moreover, the minimum absolute value selection circuit for still images
An image without blur is obtained regardless of the presence of 606.

By performing the temporal filter processing in this manner, the image quality deterioration due to the erroneous determination of the motion detection described above can be made inconspicuous, and a high-quality television image can be obtained.

However, in the above-described television signal processing device, in order to realize a freeze function for taking out a desired screen, an apparatus having a freeze function at the output of the television signal processing device is required. Although it is conceivable to arrange them in series, such a configuration has a technical problem that the device scale is increased.

In view of the above, the present invention provides a television signal processing device that has not only a temporal filter process but also a freeze function by using a new television signal processing device and has a device size substantially equal to that of a conventional device. The purpose is to:

Means for Solving the Problems A television signal processing apparatus according to the present invention comprises a first low-pass filter (first LPF) having a desired cut-off frequency, and a high-pass filter having a cut-off frequency crossing over the cut-off frequency. Filter means, first signal switching means having at least two input terminals, one of which is supplied with the output of the HPF, and frame memory, wherein the output signal supplied from the first signal switching means Second low-pass filter means (2L) for performing low-pass filtering in the time-frequency domain
PF), synthesizing means for synthesizing the output supplied from each of the second LPF and the first LPF, and outputting either the output supplied from the frame memory or the output supplied from the synthesizing means. A second signal switching means as an input, wherein either the input of the HPF or the output from the synthesizing means is supplied as the other input of the first signal switching means, and the signal output is transmitted substantially as a still image A mode control means for controlling a mode and a mode for transmitting as an output subjected to temporal filter processing.

In the television signal processing apparatus according to the present invention, when processing a television signal, the television signal is controlled substantially exclusively for reading when controlled to the still image mode in accordance with the control signal supplied from the mode control means. From the specified frame memory. When the mode is controlled to the temporal filter mode, the supplied signal is separated into a low-frequency component and a high-frequency component, and the low-frequency component in the time-frequency domain using a frame memory for the high-frequency component. The low-pass frequency component and the high-pass frequency component subjected to the low-pass filter processing are combined and output.

Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings. However, those having the same purpose and operation as those in FIG. 4 showing a conventional example will be denoted by the same reference numerals and detailed description will be omitted. .

FIG. 1 is a block diagram showing a television signal processing apparatus according to an embodiment of the present invention. In the following drawings, elements common to FIG. 4 are denoted by the same reference numerals.

A mode control signal input terminal 609, a first switching circuit 610 for selectively outputting either the input or the output of the HPF 603 according to a mode control signal supplied from the mode control signal input terminal 609, and a frame memory 604. It is characterized in that a second switching circuit 611 for selecting either the supplied output or the output supplied from the synthesizing circuit 607 according to the mode control signal and supplying the selected output to the signal output terminal 608 is provided. .

In the television signal processing apparatus shown in FIG. 1, the input of the HPF 603 is selected in the first switching circuit 610 by the mode control signal supplied to the mode control signal input terminal 609, and the input of the HPF 603 is selected in the second switching circuit 611. When the first switching circuit 610 and the second switching circuit 611 are controlled so that the output from the frame memory 604 is selected, and when the frame memory 604 is controlled to the read-only mode,
One desired screen can be frozen and taken out as a still image.

On the other hand, the first switching circuit 61
At 0, the output of the HPF 603 is selected and the second switching circuit 611 is selected.
In the case where the first switching circuit 610 and the second switching circuit 611 are controlled so that the output from the synthesizing circuit 607 is selected, the input signal is known to have the configuration shown in FIG. The output obtained by performing the same temporal filter processing as that of the television signal processing device is obtained.

Next, as shown in FIG. 2, for example, a mode control signal input terminal 609 and either the output of the HPF 603 or the output of the synthesizing circuit 607 are sent to the television signal processing device 6 from the mode control signal input terminal 609. Another embodiment in which a first switching circuit 612 for selectively outputting according to a supplied mode control signal and the second switching circuit 611 will be described.

In the television signal processing device 6 shown in FIG.
According to the mode control signal supplied to the mode control signal input terminal 609, the output from the combining circuit 607 is selected in the first switching circuit 612, and the output from the frame memory 604 is selected in the second switching circuit 611. When the first switching circuit 612 and the second switching circuit 611 are controlled and the frame memory 604 is controlled to the read-only mode, the desired one screen subjected to the temporal filter processing is frozen to achieve higher image quality. It can be extracted as a simple still image.

On the other hand, the first switching circuit 61
In step 2, the output of the HPF 603 is selected, and the second switching circuit 611 is selected.
In the case where the first switching circuit 612 and the second switching circuit 611 are controlled so that the output from the synthesizing circuit 607 is selected, the well-known configuration shown in FIG. The output obtained by performing the same temporal filter processing as that of the television signal processing device is obtained.

As described above, according to the embodiment of the present invention, the mode control signal input terminal 609, the first switching circuit 610, and the second switching circuit 61
1, and HP is provided as one input of the first signal switching circuit 610.
By supplying the input of F603, a desired one screen can be frozen and taken out as a still image.

Further, a mode control signal input terminal 609, a first switching circuit 6
12, a second switching circuit 611 is provided, and a first signal switching circuit 612 is provided.
By supplying the output supplied from the synthesizing circuit 607 as one input of the image, the one screen subjected to the temporal filter processing is frozen, and the image quality deterioration due to incomplete motion discrimination is not noticeable. It can be taken out, and the cost performance of the device can be further improved.

Next, a case will be described in which the above-described television signal processing apparatus is applied to, for example, a television signal receiving apparatus as shown in FIG. In FIG. 3, a signal processing circuit 2 performs still image signal processing and moving image signal processing on an interlaced scanning television signal input from a television signal input terminal 1 and supplies the processed signal to a mixing circuit 4. I do.

The mixing circuit 4 mixes the still image signal-processed signal and the moving image signal-processed signal supplied from the signal processing circuit 2 into a motion detection signal from the motion detection circuit 3 and mixes the signals. Supply to circuit 5.

According to the motion detection signal from the motion detection circuit 3, the scan conversion circuit 5 uses the signal of one field before in the case of a still image, and uses the signal of the upper and lower lines, for example, in the case of a moving image, to generate an interpolation signal. After converting the interlaced scanning signal into a progressive scanning signal, the signal is supplied to the television signal processing device 6 having the configuration shown in FIG.

The inverse matrix circuit 7 is a television signal processor 6
Are converted into R, G, B signals, and R signal output terminals 8, G
The signals are supplied to a signal output terminal 9 and a B signal output terminal 10, respectively.

Since the current interlaced television signal divides a signal of one screen into two fields (even and odd fields), signals of adjacent lines on the screen exist in different fields. Therefore, when the image of the interlaced scanning signal is frozen, multiline blur between fields occurs in principle.

However, in the television signal receiving apparatus of the present invention configured as described above, since the progressive-scanning signal after scan conversion is frozen, it can be extracted as a high-quality still image signal without multi-line blur. it can.

In the above application example, the television signal processing device having the configuration shown in FIG. 1 was used.
If the television signal processing apparatus shown in FIG. 2 is used, deterioration of image quality due to incomplete motion discrimination can be made inconspicuous, and a still image signal with higher image quality can be extracted.

Effect of the Invention As described above, according to the present invention, a freeze function can be provided, so that the practical value of the device can be significantly improved, and its industrial value is great.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram of a television signal processing apparatus according to one embodiment of the present invention, FIG. 2 is a block diagram of a television signal processing apparatus according to another embodiment of the present invention, and FIG. FIG. 4 is a block diagram of an application example in which the television signal processing device according to the embodiment of the present invention is applied to a television signal receiving device. FIG. 4 is a block diagram of a known television signal processing device. 602: LPF, 603: HPF, 604: Frame memory, 606
... Minimum absolute value selection circuit, 609 mode control signal input terminal, 610 first switching circuit, 611 second switching circuit, 612 first switching circuit, 1 television signal Input terminal, 2 ... signal processing circuit, 3 ... motion detection circuit,
4 a mixing circuit, 5 a scan conversion circuit, 6 a television signal processing device, 7 an inverse matrix circuit.

 ──────────────────────────────────────────────────の Continuing on the front page (72) Katsumi Morita 1006 Kazuma Kadoma, Kadoma, Osaka Prefecture Inside Matsushita Electric Industrial Co., Ltd. (72) Yuichi Ninomiya 1-10-11 Kinuta, Setagaya-ku, Tokyo Japan Broadcasting Corporation Inside the Broadcasting Technology Research Institute (72) Inventor Toshiro Omura 2-2-1 Jinnan, Shibuya-ku, Tokyo Inside the Japan Broadcasting Corporation Broadcasting Center

Claims (6)

(57) [Claims] A first low-pass filter having a desired cut-off frequency and a high-pass filter having a cut-off frequency crossing over a cut-off frequency of the first LPF.
F), at least two input terminals, first signal switching means in which the output of the HPF is supplied to the one terminal, a frame memory, and an output signal supplied from the first signal switching means. A second low-pass filter means (second LPF) for performing low-pass filter processing in the frequency domain; a synthesizing means for synthesizing the outputs of the second LPF and the first LPF to produce an output; A second signal switching means for selecting either the supplied output or the output supplied from the combining means as an input; and a mode control means for controlling the first and second signal switching means and the frame memory. A television signal processing apparatus, comprising: an HPF input or an output from a synthesizing unit supplied as the other input of the first signal switching unit. 2. The television signal processing apparatus according to claim 1, wherein the other input of the first signal switching means is an HPF input. 3. The television signal processing apparatus according to claim 1, wherein the other input of said first signal switching means is an output of said synthesizing means. 4. The television signal according to claim 2, wherein the mode control means controls the first and second signal switching means and the frame memory so as to substantially transmit a still image as an output. Processing equipment. 5. The apparatus according to claim 1, wherein the mode control means controls the first and second signal switching means and the frame memory so as to output an output signal which is substantially temporally filtered as an output. Television signal processing device. 6. First and second signal processing means for performing still image signal processing and moving image signal processing on an interlaced scanning television signal as an input signal, respectively, and detects image movement based on the input signal. A motion detecting means for detecting, a mixing means for mixing output signals of the first and second signal processing means in accordance with a control signal supplied from the motion detecting means, and a control means for controlling an interlaced scanning signal outputted by the mixing means. 2. The television signal processing apparatus according to claim 1, further comprising: scan conversion means for converting a signal into a progressive scan signal in accordance with the signal, wherein an output signal of the scan conversion means is input.