JPH09116830A - Video signal detector and television receiver - Google Patents

Abstract

PROBLEM TO BE SOLVED: To avoid mis-discrimination of impulse noise to be a video signal. SOLUTION: A non-image discrimination circuit 3 discriminates a line to be a non-picture part when a comparator circuit 11 and a discrimination circuit 13 discriminate non-picture part. A picture element level operating state discrimination circuit 33 discriminates whether or not the discrimination circuit 13 malfunctions based on an output of the discrimination circuit 31 and a line mean value. A video image change point detection circuit 43 detects the number of times of equality between outputs of the characters 11, 41 to discriminate whether or not the detected value is larger than a prescribed value (n). A non- picture part detection output selection circuit 45 keeps an output of the discrimination circuit 31 when the discrimination circuit 13 is discriminated to be normal, keeps an output of the comparator 11 when the discrimination circuit malfunctions and the detected value is higher than (n) and keeps a current output when the discrimination circuit malfunctions and the detected value is less than the (n).

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a video signal detection device for detecting whether or not an input video signal is a signal in a non-picture portion, and a television receiving device employing the video signal detection device.

[0002]

2. Description of the Related Art Package programs such as television broadcast movie programs and laser discs (LDs) and videos have a horizontally long screen with a non-picture portion called "cinemascope size" or "vista size" as shown in FIG. There is a video. In the current horizontally long television receivers, upper and lower non-image parts of these video signals are detected, and only the video part is enlarged on the display based on the detection result.

FIG. 12 shows the configuration of a conventional video signal detecting device. The luminance signal is input to the line averaging circuit 103 via the input terminal 101. The line averaging circuit 103 is
The average value of the levels of one line of the luminance signal is calculated. The comparison circuit 105 uses the average value and the reference value (ref) of each line.
And when the average value of each line is smaller than the reference value, a value of 1 which means a signal of a non-image part, and when the average value of each line is larger than the reference value, a value of 0 which means an image part are compared. Is output to the output terminal 107. As described above, it can be determined for each line whether or not the signal is a non-image portion signal.

[0004]

However, in the conventional video signal detecting apparatus, when the impulse noise is mixed in the non-picture portion of the video signal, the noise of the non-picture portion is erroneously determined as the video signal. In addition, there is a risk that an impulse-shaped image such as a subtitle in which the average of the level of one line is small is erroneously determined as a non-image portion.

Therefore, it is an object of the present invention to provide a video signal detecting device which does not erroneously determine noise in a non-picture portion as a video signal, and does not erroneously determine subtitles as a non-picture portion. And

It is another object of the present invention to provide a television receiving device which employs the above-mentioned video signal detecting device and displays only a main image portion excluding a non-image portion on a display device in a large size.

[0007]

[Means for Solving the Problems]

(Video Signal Detection Device) (First Configuration Example) First averaging means for calculating an average of the levels of at least the effective pixel portion of one line of the input luminance signal, the output of the first averaging means, and the first averaging means. First comparing means for comparing with a reference value and whether or not the signal of each line is a signal of a non-image part by counting the number of pixels having a level of a predetermined value or more of the input luminance signal for one line Pixel level non-image area determining means for determining the above, the first comparing means and the pixel level non-image area determining means for determining whether or not the signal of each line is a non-image area signal. The image area determination means, the vertical edge detection means for detecting a vertical edge from the output from the first averaging means, the output of the vertical edge detection means and the output of the non-image area determination means match for one field. Border line comparison hand that compares whether or not A second comparing means for comparing the output of the first averaging means with a second reference value larger than the first reference value, and the outputs of the first and second comparing means for a predetermined period. Between the first image change point detecting means for detecting the number of coincidences between the two, determining whether the detected value is larger than a predetermined value n (n> 0), and outputting the same, and the output of the first comparing means. And an output of the non-image area determination means, and a non-image area detection output selection means for selecting an output based on the output of the boundary line comparison means and the output of the first image change point detection means. The non-image area detection output selecting means outputs the output of the non-image area judging means when both inputs of the boundary line comparing means are coincident during one field, and both inputs of the boundary line comparing means are one. The fields do not match and the first video change point detection means performs the detection. Is larger than the predetermined value n, the output of the first comparison means is output, both inputs of the boundary line comparison means do not match for one field, and the first image change point detection means outputs the same. When the detected value is less than the predetermined value n, the output is output without switching the input.

(Second Configuration Example) First averaging means for calculating the average of the levels of at least the effective pixel portion of one line of the input luminance signal, the output of the first averaging means, and the first reference value. By comparing the number of pixels having a level equal to or higher than a predetermined value of the input luminance signal for one line, and determining whether the signal of each line is a signal of a non-image portion. Pixel level non-image portion determination means, and the first
Of the output of the first averaging means, and the output of the first averaging means for judging whether or not the signal of each line is the signal of the non-image part A second comparison unit that compares a second reference value that is larger than the first reference value and a number that the outputs of the first and second comparison units match for a predetermined period are detected, and the detected value is detected. Is a predetermined value n
A first video change point detecting means for determining and outputting whether or not greater than (n>0); a field difference detecting means for calculating an inter-field difference of the output of the pixel level non-image area determining means; An absolute value means for taking the absolute value of the difference value from the field difference detection means, a third comparison means for comparing the output of the absolute value means with a third reference value and outputting a comparison result, the first comparison means The non-image area detection power selecting means which receives the output of the comparing means and the output of the non-image area determining means and selects the output by the output of the third comparing means and the output of the first image change point detecting means, The non-image area detection output selecting means outputs the output of the non-image area determining means when the output of the absolute value means is smaller than the third reference value, and the output of the absolute value means is the third reference value. Value exceeds and before the first image change point detection means When the detected value is larger than the predetermined value n, the output of the first comparing means is output, the output of the absolute value means exceeds the third reference value, and the output of the first video change point detecting means is detected. When the detected value is less than the predetermined value n, the output is output without switching the input.

(Third Configuration Example) First averaging means for calculating the average of the levels of at least the effective pixel portion of one line of the input luminance signal, the output of the first averaging means and the first reference value. And a pixel for determining whether or not the signal of each line is a signal of a non-image portion by counting the number of pixels having a predetermined value level of the input luminance signal for one line. A non-image area determination unit that determines whether or not the signal of each line is a non-image area signal based on both outputs of the level non-image area determination unit, the first comparison unit, and the pixel level non-image area determination unit. A second comparing means for comparing the output of the first averaging means with a second reference value larger than the first reference value, and the outputs of the first and second comparing means for a predetermined period. The number of coincidences is detected, and the detected value is a predetermined value n (n
> 0), a first image change point detecting means for determining and outputting whether it is larger than S>, and S for determining S / N of the input image signal.
/ N determination means, the output of the first comparison means and the output of the non-image area determination means are input, and the output is selected by the S / N determination means and the output of the first video change point detection means. In the non-image area detection output selection means and the non-image area detection output selection means, the S / N determination means is the S of the input video signal.
When it is determined that the S / N ratio is good, the output of the non-image area determining unit is output, and the S / N determining unit outputs the S / N of the input video signal.
If it is determined that N is bad and the detected value by the first image change point detection means is larger than the predetermined value n, then the first
The output of the comparison means is output, the S / N determination means determines that the S / N of the input video signal is bad, and the detection value of the first video change point detection means is less than the predetermined value n. In the case of, output is performed without switching the input.

(Fourth configuration example) An averaging means for calculating the average of the levels of at least the effective pixel portions of one line of the input luminance signal and a first comparing means for comparing the output of the averaging means with a first reference value. Comparing means for comparing the level of the input luminance signal with a second reference value, and outputting a signal when the level of the input luminance signal is higher than the second reference value; Third comparing means for comparing the level of the input luminance signal with a third reference value larger than the second reference value, and outputting a signal when the level of the input luminance signal is larger than the third reference value. An image change point detecting means for outputting a signal when a signal is output from the second and third comparing means at the same pixel, and a counting means for counting the output of the image change point detecting means for one line. And the counting means Fourth comparing means for comparing the result with a fourth reference value, holding means for holding the output of the fourth comparing means for one line, both outputs of the first comparing means and the holding means And a non-image area determination unit that determines whether or not the signal of each line is a non-image area signal.

(Television Receiving Device) (First Configuration Example) Scanning of a video signal excluding the signal of the line of the non-image part detected by the video signal detecting device according to any one of the first to fourth configuration examples. It is characterized in that the interval between the lines is expanded and displayed on the display device.

(Second Configuration Example) The number of scanning lines of the video signal except the signal of the line of the non-image part detected by the video signal detecting device according to any one of the first to fourth configurations is converted, It is characterized by displaying on a display device.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows a first embodiment of a video signal detecting device of the present invention.

The luminance signal is supplied to the line averaging circuit 9 of the first line average non-image area detecting circuit 7 through the input terminal 1. The line averaging circuit 9 calculates the average of the levels of one line of the luminance signal and supplies the average to the comparing circuit 11 of the first line average non-image area determining circuit 7.

The comparison circuit 11 compares the line average value with the first reference value (ref1). When the line average value is less than or equal to the first reference value (ref1), the line is determined to be a non-image area. Then, for example, a value of 1 is supplied to the non-image area determination circuit 31.
Further, the comparison circuit 11 determines that the line average value is the first reference value (r
When it exceeds ef1), it is determined that the line is a video signal and a value of 0 is supplied to the non-image area determination circuit 31.

A luminance signal is supplied to the pixel level non-image area determination circuit 13 via the input terminal 1, and a clock (CK) and a horizontal synchronization signal (H) are supplied to the pixel level non-image area determination circuit 13 via the input terminal 3. The pixel level non-image area determination circuit 13 is a circuit that performs the non-image area determination at the pixel level of the luminance signal.

FIG. 2 shows a first specific example of the pixel level non-image area determination circuit 13. The clock (CK) and the horizontal synchronizing signal (H) are supplied to the timing generation circuit 17 via the input terminal 3.
Is input to The timing generation circuit 17 generates first and second timing pulses from the clock (CK) and the horizontal synchronization signal (H). The first timing pulse is supplied to the counter 19 described later. The second timing pulse is supplied to the latch circuit 23 described later.

The luminance signal is input to the comparison circuit 15 via the input terminal 1. The comparison circuit 15 sequentially compares the level of the arrived pixel and the second reference value (ref2). When the pixel level is higher than the second reference value (ref2), that is, when the pixel is an image or noise, a pulse is output each time. The counter 19 counts the pulses from the comparison circuit 15 for one line. Then, it is reset by the first timing pulse.

The comparison circuit 21 compares the counter value before being reset with the third reference value (ref3). The number of pixels determined to be video or noise is the third reference value (re
When it exceeds f3), it is determined that the line is a video signal and a value of 0 is output. When the number of pixels determined to be an image or noise is smaller than the third reference value (ref3), it is determined that the line is a signal of a non-image portion, and a value of 1 is output.

The latch circuit 23 at the next stage holds the output of the comparison circuit 21 for one line in synchronization with the rising edge of the second timing pulse that arrives at the end of one line.
The latch circuit 23 updates the content with the output of the comparison circuit 21 at that time at the next rising edge of the second timing pulse after one line. The output of the latch circuit 23 is supplied to the non-image area determination circuit 31 via the output terminal 25.

FIG. 3 shows a second concrete example of the pixel level non-image area judging circuit 13. In this specific example, a video of a caption as shown in FIG. 4 can be determined as a video signal. Note that the caption signal is a binary signal, and its level difference from the peripheral part is very large (see, for example, A in FIG. 4).
The line A ') constitutes the circuit of FIG. 2 that are the same as those in the circuit of FIG. 2 are designated by the same reference numerals, and detailed description thereof will be omitted.

The luminance signal is input to the comparison circuit 15 via the input terminal 1. The comparison circuit 15 sequentially compares the arrived pixel level with the second reference value (ref2). When the pixel level is higher than the second reference value (ref2), that is, when the pixel is an image or noise, a pulse is output each time.

The luminance signal is input to the comparison circuit 27 via the input terminal 1. The comparison circuit 27 sequentially compares the incoming pixel level with a fourth reference value (ref4) larger than the second reference value (ref2). When the pixel level is higher than the fourth reference value (ref4), that is, when the pixel is an image or noise, a pulse is output each time.

The video change point detection circuit 29 in the next stage generates a pulse only when the pixels to which pulses are simultaneously output from both the comparison circuits 15 and 27, and supplies the pulse to the counter 19.

The operations of the counter 19, the comparison circuit 21 and the latch circuit 23 are the same as in the case of FIG.

Returning to FIG. 1, both outputs of the comparison circuit 11 and the pixel level non-image area determination circuit 13 are supplied to the non-image area determination circuit 31. The non-image area determination circuit 31 is a non-image area only when the comparison circuit 11 and the pixel-level non-image area determination circuit 13 supply a value of 1 which means that the image area is the non-image area. Then, for example, a value of 1 is output.

The non-picture area judging circuit 31 is the comparing circuit 11
And a pixel level non-image area determination circuit 13 both supply a value of 0 which means a video signal, and one of both supplies a value of 0 which means a video signal. If it is, the line is determined to be a video signal and a value of 0 is output.

In this way, the first line average no-picture area determination circuit 7, the pixel level no-picture area judgment circuit 13 and the no-picture area judgment circuit 31 constitute the no-picture area detection circuit 5.

Next, the line average value from the line averaging circuit 9 is also supplied to the vertical edge detecting circuit 35 of the pixel level operation state judging circuit 33. Vertical edge detection circuit 35
Detects a vertical edge from the change in line average value. Then, the vertical edge detection circuit 35 detects, for example, a value of 0 when the vertical edge is detected at the boundary (rising edge) between the non-image area and the main image area in the upper part of one field, and the next vertical edge (falling edge) is detected. Until the next stage, the boundary line comparison circuit 37
Output to

Further, the vertical edge circuit 35 changes the output value from 0 to 1 when the vertical edge is detected at the boundary (falling edge) between the inner main picture portion of one field and the lower non-picture portion, and The boundary line comparison circuit 37 of the stage is supplied.

The output from the non-image area determination circuit 31 is also input to the boundary line comparison circuit 37. The output of the non-image area determination circuit 31 changes from a value of 1 to 0 when the upper non-image area in one field shifts to the main image area. Then, when the main main picture part of one field shifts to the lower non-picture part, 0 to 1
To the value of.

The boundary line comparison circuit 37 outputs the output of the vertical edge detection circuit 35 and the non-image area determination circuit 3 for one field.
It is determined whether the outputs of 1 match. When the video signal has a non-picture portion and a main picture portion, the output of the vertical edge detection circuit 35 and the output of the non-picture portion determination circuit 31 match, and the boundary line comparison circuit 37 determines that the pixel level non-picture portion determination circuit. 13, that is, the non-image area determination circuit 31 determines that it is operating normally.

The boundary line comparison circuit 37 determines whether the output of the vertical edge detection circuit 35 and the output of the non-image area determination circuit 31 do not match during one field, and the pixel level non-image area determination circuit. It is determined that 13 is causing an erroneous determination due to noise.

The boundary line comparison circuit 37 controls the operation of the non-image area detection output selection circuit 45, which will be described later, according to such a determination result. The vertical edge detection circuit 35 and the boundary line comparison circuit 37 form a pixel level operation state determination circuit 33.

The line average value of the line average circuit 9 is further supplied to the comparison circuit 41 of the second line average non-image area determination circuit 39. The comparator circuit 41 compares the average value output with a fifth reference value (ref5) larger than the first reference value (ref1), and when the line average value is equal to or less than the fifth reference value (ref5), The line is determined to be a non-image portion, and a value of 1, for example, is output. Further, the comparison circuit 41 has the line average value of the fifth value.
When it exceeds the reference value (ref5) of, the line is judged to be a video signal and a value of 0 is output.

The outputs of the comparison circuits 11 and 41 are supplied to the video change point detection circuit 43. This image change point detection circuit 4
3 detects the number of coincidence between the outputs of the comparison circuits 11 and 41 during one field, and determines whether or not it is larger than a predetermined value n (n> 0).

When the number (detection value) where the outputs of the comparison circuits 11 and 41 coincide with each other is larger than the predetermined value n, all of them are video signals during one field, or there is no signal as shown in FIG. 5 (a). It can be determined that the video signal has an image portion and a main image portion.

Then, when the number (detection value) where the outputs of the comparison circuits 11 and 41 coincide with each other is equal to or less than the predetermined value n, FIG.
As shown in, it is determined that it is not known whether the signal is a video signal having a non-picture portion and a main picture portion or noise.

The determination result of the image change point detection circuit 43 controls the operation of the non-image area detection output selection circuit 45 described below together with the determination result of the pixel level operation state determination circuit 33 as described above.

Both outputs of the non-picture area determination circuit 31 and the comparison circuit 11 are supplied to both input terminals of the non-picture area detection output selection circuit 45. The non-image area detection output selection circuit 45 outputs the output of the non-image area determination circuit 31 when the pixel level operation state determination circuit 33 determines that the pixel level non-image area determination circuit 13 is operating normally. Output to 47.

When the pixel level operation state determination circuit 33 determines that the pixel level no-image area detection circuit 13 is not operating normally, the no-image area detection output selection circuit 45 outputs the output of the no-image area determination circuit 31. Do not select.

When the video change point detection circuit 43 determines that the signals are all video signals or video signals having a non-picture portion and a main picture portion (detection value ≧ n), the non-picture portion detection output The selection circuit 45 outputs the output of the comparison circuit 11 to the output terminal 47. If the video change point detection circuit 43 determines that the signal is a video signal having a non-picture portion and a main picture portion or noise (detection value <n), the non-picture portion detection output The selection circuit 45 maintains the output as it is without switching the selection.

As described above, the pixel level operation state determination circuit 33 determines the operation state of the pixel level non-image area determination circuit 13, and it is determined that the pixel level non-image area determination circuit 13 malfunctions due to impulse noise. In this case, the selection operation of the non-image area detection output selection circuit 45 is controlled according to the determination result of the video change point detection circuit 43.

FIG. 6 shows a second video signal detecting device according to the present invention.
An embodiment will be described. The only difference between the second embodiment and the above-described first embodiment of FIG. 1 is the difference in the configuration of the pixel level operation state determination circuits 33 and 51. Therefore, in FIG.
The same components as those of the above are denoted by the same reference numerals, and detailed description thereof will be omitted.

The output of the image part level non-image part determination circuit 13 is
It is supplied to the field difference detection circuit 53. The field difference detection circuit 53 obtains the inter-field difference of the determination result of the pixel level non-image area determination circuit 13. Absolute value circuit (AB
S) 55 takes the absolute value of the inter-field difference and supplies it to the comparison circuit 57 at the next stage.

The comparison circuit 57 compares the absolute value from the absolute value circuit 55 with the sixth reference value (ref6). When the pixel level non-image area determination circuit 13 is operating normally,
It is considered that there is little variation in the judgment output between fields.
Therefore, when the absolute value is smaller than the sixth reference value (ref6), the comparison circuit 57 determines that the pixel level non-image area determination circuit 13 is operating normally.

Then, the absolute value is the sixth reference value (re
When it exceeds f6), the comparison circuit 57 determines that the pixel level non-image area determination circuit 13 is malfunctioning.

The output of the comparison circuit 57 is connected to the continuity detection circuit 5
9. A concrete example of the continuity detection circuit 59 is shown in FIG.

The output of the comparison circuit 57 is supplied to the 1-field delay circuit 63 via the input terminal 61. The 1-field delay circuit 63 delays the input for 1 field and supplies it to the 1-field delay circuit 65 at the next stage. The 1-field delay circuit 65 delays the input for 1 field and supplies it to the 1-field delay circuit 67 at the next stage. 1
The field delay circuit 67 delays the input for one field and supplies it to the next one-field delay circuit 69.
The 1-field delay circuit 69 delays the input for 1 field and supplies it to the OR circuit 71.

In addition to the output of the 1-field delay circuit 69, the OR circuit 71 is supplied with the output of the comparison circuit 57 and the outputs from the 1-field delay circuits 63, 65 and 67. The OR circuit 71 takes the OR of these inputs and outputs it to the non-image area detection output selection circuit 45 via the output terminal 73 to control the selection operation.

The 1-field delay circuit used in the continuity detecting circuit 59 is not limited to four.

The selection operation of the non-picture area detection output of the non-picture area detection output selection circuit 45 is controlled by the judgment results of the pixel level operation state judgment circuit 51 and the video change point detection circuit 43 as in FIG.

As described above, the pixel level operation state determination circuit 51 determines the operation state of the pixel level non-image area determination circuit 13, and it is determined that the pixel level non-image area determination circuit 13 malfunctions due to impulse noise. In this case, the selection operation of the non-image area detection output selection circuit 45 is controlled according to the determination result of the video change point detection circuit 43.

FIG. 8 shows the third embodiment of the video signal detecting device of the present invention.
An embodiment will be described. The only difference between the third embodiment and the first embodiment shown in FIG. 1 is the difference in the configuration of the pixel level operation state determination circuits 33 and 75. Therefore, in FIG.
The same components as those of the above are denoted by the same reference numerals, and detailed description thereof will be omitted.

S / N of pixel level operation state determination circuit 77
The determination circuit 77 uses the S / S of the input video signal for each field.
N is detected. In the example of FIG. 8, an AGC circuit is adopted as the S / N determination circuit 77.

Therefore, the AGC voltage is supplied to the S / N determination circuit 77. When the S / N ratio is bad, the S / N judgment circuit 77 moves in the direction of reducing the gain.
The output level of 7 becomes smaller. The better the S / N, the higher the output level of the S / N determination circuit 77.

The comparison circuit 79 at the next stage is the S / N determination circuit 7
The output of No. 7 is compared with the seventh reference value (ref7). When the output of the S / N determination circuit 77 is larger than the seventh reference value (ref7), the comparison circuit 79 determines that the pixel level non-image area determination circuit 13 is operating normally.

The output of the S / N determination circuit 77 is the seventh
If it is less than the reference value (ref7) of, the comparison circuit 79 determines that the pixel level non-image area detection circuit 13 is malfunctioning.

The selection operation of the non-image area detection output selection circuit 45 is controlled by the determination results of the pixel level operation state determination circuit 75 and the image change point detection circuit 43, as in FIG.

As described above, the pixel level operation state determination circuit 75 determines the operation state of the pixel level non-image area determination circuit 13, and it is determined that the pixel level non-image area determination circuit 13 malfunctions due to impulse noise. In this case, the selection operation of the non-image area detection output selection circuit 45 is controlled according to the determination result of the video change point detection circuit 43.

In FIG. 8, as the S / N determination circuit 77, a horizontal AFC circuit can be considered instead of the AGC circuit. This is because the phase error is detected by the horizontal AFC circuit when the S / N is bad. However,
Unlike the case of the AGC circuit, when the S / N of the input video signal is good, the output level of the S / N determination circuit 77 is low.
It should be noted that the output level of the S / N determination circuit 77 increases as the S / N of the input video signal deteriorates.

The line averaging circuit 9 of the embodiments of FIGS. 1, 6 and 8 calculates the average of the levels of one line of the luminance signal, but instead of this, the average of the effective pixel portion of one line is calculated. It is possible to determine whether or not it is a non-image area, and there are different ways of taking the average value.

When the circuit of FIG. 3 is adopted as a concrete example of the pixel level non-image area judging circuit 13, the video signal detecting device may be composed of only the non-image area detecting circuit 5.
In this case, the output of the non-image area determination circuit 31 becomes the output of the video signal detection device.

FIG. 9 shows a first embodiment of a television receiver employing the above-mentioned video signal detecting device.

The input composite video signal is separated from the video signal processing unit 83 via the input terminal 81 by the synchronizing signal and the clock (C
K) It is supplied to the generating unit 85. The video signal processing unit 83
Desired signal processing is performed on the input composite video signal to supply the video signal to the display device 91 and the luminance signal to the input terminal 1 of the video signal detection device 87 of the present invention.

Synchronous signal separation / clock (CK) generator 8
Reference numeral 5 separates a horizontal synchronizing signal (H) and a vertical synchronizing signal (V) from the input composite video signal and also a clock (CK).
Occurs. The horizontal synchronization signal (H) is supplied to the display device 91 and the input terminal 3 of the video signal detection device 87. The vertical synchronization signal (V) is supplied to the vertical deflection control device 89.
The clock (CK) is supplied to the input terminal 3 of the video signal detection device 87.

The video signal detecting device 87 determines whether the video signal is a normal video signal or a video signal having a caption, or a video signal having a non-picture portion and a main picture portion, based on the luminance signal, the horizontal synchronizing signal and the clock (CK). Then, it is supplied to the vertical deflection control circuit 89 via the output terminal 47.

When the video signal is a video signal having a non-picture part and a main picture part, the vertical deflection control device 89 extends the interval of the scanning lines of the display device 91 to display the main picture part as shown in FIG. The entire screen of the device 91 is displayed.

FIG. 10 shows a second embodiment of a television receiving device which employs the above-mentioned video signal detecting device.
Only the points different from the first embodiment of FIG. 9 will be described.

Synchronous signal separation / clock (CK) generator 8
The horizontal synchronizing signal (H) and the vertical synchronizing signal (V) from 5 are
It is supplied to the deflecting device 93 as in the conventional case. Deflection device 93
Scans the scanning line with the display device 91 as in the conventional case.

The video signal detection device 87 supplies the non-image portion detection output to the scanning line conversion circuit 95 arranged between the video signal processing portion 83 and the display device 91. When the video signal is a video signal having a non-picture portion and a main picture portion, the scanning line conversion circuit 95 increases the number of scanning lines in the main picture portion. As a result, as shown in FIG. 11, the main image portion is displayed on the full screen of the display device 91.

[0072]

According to the video signal detecting apparatus of the present invention, the impulse noise of the non-picture portion is not erroneously determined as the video signal, and the caption is not erroneously determined as the non-picture portion. .

Further, the television receiving device which employs the video signal detecting device of the present invention can display only the main image portion excluding the non-image portion on the full screen of the display device.

[Brief description of the drawings]

FIG. 1 is a diagram showing a configuration of a first embodiment of a video signal detection device of the present invention.

FIG. 2 is a diagram showing a first specific example of a pixel level non-image area determination circuit used in the video signal detection device of the present invention.

FIG. 3 is a diagram showing a second specific example of a pixel level non-image area determination circuit used in the video signal detection device of the present invention.

FIG. 4 is a diagram showing changes in the level of a subtitle image and a luminance signal.

FIG. 5 is a diagram showing a change in level of an input luminance signal.

FIG. 6 is a diagram showing a configuration of a second embodiment of a video signal detection device of the present invention.

FIG. 7 is a diagram showing a configuration of a continuity detection circuit of a pixel level operation state determination circuit adopted in FIG.

FIG. 8 is a diagram showing a configuration of a third embodiment of a video signal detection device of the present invention.

FIG. 9 is a diagram showing a configuration of a first embodiment of a television receiving device adopting the video signal detecting device of the present invention.

FIG. 10 is a diagram showing a configuration of a second embodiment of a television receiving device adopting the video signal detecting device of the present invention.

FIG. 11 is a diagram showing a state in which a horizontally long image having a non-image portion at the top and bottom is displayed on the screen of the display device.

FIG. 12 is a diagram showing a configuration of a conventional video signal detection device.

FIG. 13 is a diagram showing a horizontally long image having non-image portions at the top and bottom.

[Explanation of symbols]

5 ... No-image area detection circuit, 7 ... First line average no-image area determination circuit, 9 ... Line average circuit, 11 ... Comparison circuit, 13 ... Pixel level no-image area determination circuit, 15 ... Comparison circuit, 17 ... Timing Generation circuit, 19 ... Counter, 21 ... Comparison circuit, 2
3 ... Latch circuit, 27 ... Comparison circuit, 29 ... Image change point detection circuit, 31 ... No-picture area determination circuit, 33 ... Pixel level operation state determination circuit, 35 ... Vertical edge detection circuit, 37 ... Boundary line comparison circuit, 39 ... second line average non-image area determination circuit, 41 ... comparison circuit, 43 ... video change point detection circuit, 45
... non-image area detection output selection circuit, 51 ... Pixel level operation state determination circuit, 53 ... Field difference detection circuit, 55 ... Absolute value circuit (ABS), 57 ... Comparison circuit, 59 ... Continuity detection circuit, 63 to 69 ... 1-field delay circuit, 71 ... O
R circuit, 75 ... Pixel level operation state determination circuit, 77 ... S
/ N determination circuit, 79 ... Comparison circuit, 83 ... Video signal processing section, 85 ... Sync signal separation, clock (CK) generation section, 8
7 ... Video signal detection device, 89 ... Vertical deflection control device, 91
... display device, 93 ... deflection device, 95 ... scanning line conversion circuit.

Continuation of the front page (72) Inventor Shigeki Kamimura 3-3-9 Shimbashi, Minato-ku, Tokyo Toshiba Abu E. Co., Ltd.

Claims (10)

[Claims] 1. A first averaging means for calculating an average of levels of at least effective pixel portions of one line of an input luminance signal, and a first averaging means for comparing an output of the first averaging means with a first reference value. And a pixel level non-image section for judging whether or not the signal of each line is a non-image section signal by counting the number of pixels having a level equal to or higher than a predetermined value of the input luminance signal for one line. A judging means; a non-picture part judging means for judging whether or not the signal of each line is a non-picture part signal by both outputs of the first comparing means and the pixel level non-picture part judging means; 1. A vertical edge detecting means for detecting a vertical edge from the output from the averaging means of 1, and a boundary line for comparing whether the output of the vertical edge detecting means and the output of the non-image area determining means match for one field. Comparing means, the first average Second comparing means for comparing the output of the stage with a second reference value larger than the first reference value, and detecting the number of times the outputs of the first and second comparing means match for a predetermined period. A first image change point detecting means for judging and outputting whether or not the detected value is larger than a predetermined value n (n>0); an output of the first comparing means and a non-image area judging means. The output is input, and the output of the boundary line comparison means and the first
A non-image area detection output selection means for selecting an output according to the output of the image change point detection means, and the non-image area detection output selection means is such that both inputs of the boundary line comparison means are within one field. When they match, the output of the non-image area determination means is output, both inputs of the boundary line comparison means do not match for one field, and the detection value of the first video change point detection means is the predetermined value. When the value is larger than the value n, the output of the first comparison means is output, both inputs of the boundary line comparison means do not match for one field, and the detection value in the first video change point detection means is A video signal detecting device which outputs without switching the input when the value is less than the predetermined value n. 2. A first averaging means for calculating an average of levels of at least effective pixel portions of one line of an input luminance signal, and a first averaging means for comparing an output of the first averaging means with a first reference value. And a pixel level non-image section for judging whether or not the signal of each line is a non-image section signal by counting the number of pixels having a level equal to or higher than a predetermined value of the input luminance signal for one line. A judging means; a non-picture part judging means for judging whether or not the signal of each line is a non-picture part signal by both outputs of the first comparing means and the pixel level non-picture part judging means; Second comparing means for comparing the output of the averaging means of 1 with a second reference value larger than the first reference value, and the number of times the outputs of the first and second comparing means match for a predetermined period. Is detected and whether the detected value is larger than a predetermined value n (n> 0) is determined. First image change point detecting means for determining and outputting, field difference detecting means for calculating an inter-field difference of the output of the pixel level non-image area determining means, and absolute value of a difference value from the field difference detecting means An absolute value means, a third comparing means for comparing the output of the absolute value means with a third reference value and outputting a comparison result, an output of the first comparing means and the non-image area judging means. The non-image area detection power selection means for selecting the output according to the output of the third comparison means and the output of the first image change point detection means, and the non-image area detection output selection means, When the output of the absolute value means is smaller than the third reference value, the output of the non-image area determining means is output, and the output of the absolute value means exceeds the third reference value and the first image change inspection The value detected by the output means is greater than the predetermined value n. If hearing outputs an output of said first comparing means, the output of the absolute value means the third
If the detected value of the first image change point detection means is less than the predetermined value n, the output is performed without switching the input. 3. A first averaging means for calculating an average of levels of at least effective pixel portions of one line of an input luminance signal, and a first averaging means for comparing an output of the first averaging means with a first reference value. And a pixel level non-image part determination for determining whether or not the signal of each line is a non-image part signal by counting the number of pixels having a predetermined value level of the input luminance signal for one line Means for determining whether or not a signal of each line is a signal of a non-image portion by both outputs of the first comparing means and the pixel-level non-image portion determining means; The second comparing means for comparing the output of the averaging means with the second reference value larger than the first reference value, and the number of times the outputs of the first and second comparing means match for a predetermined period. Detects and determines whether the detected value is greater than a predetermined value n (n> 0) The first image change point detecting means for outputting the output, the S / N determining means for determining the S / N of the input image signal, the output of the first comparing means and the output of the non-image area determining means are input. A non-image area detection output selection means for selecting an output based on the S / N determination means and the output of the first video change point detection means; and the non-image area detection output selection means includes the S / N determination means. Outputs the output of the non-image part judging means when it judges that the S / N of the input video signal is good, and the S / N judging means judges that the S / N of the input video signal is bad, and If the detected value of the image change point detecting means of No. 1 is larger than the predetermined value n, the output of the first comparing means is outputted, and the S / N judging means has a bad S / N of the input image signal. And the detected value by the first image change point detection means is the predetermined value n. A video signal detection device which outputs without switching the input when the value is less than the specified value. 4. The video signal detecting apparatus according to claim 1, wherein the first averaging means calculates an average value of levels of one line of the input luminance signal. 5. The pixel level non-image area determination means compares the level of the input luminance signal with a fourth reference value,
Fourth comparing means for outputting a signal when the level of the input luminance signal is higher than the fourth reference value, counting means for counting the output of the fourth comparing means for one line, and the counting means 5. A fifth comparison means for comparing the count result of No. 5 with a fifth reference value, and a holding means for holding the output of the fifth comparison means for one line are provided. 5. The video signal detection device according to any one of 4 to 4. 6. The pixel level non-image area determination means compares the level of the input luminance signal with a fourth reference value,
A fourth comparing means for outputting a signal when the level of the input luminance signal is larger than the fourth reference value; and a level of the input luminance signal and a fifth reference value larger than the fourth reference value. A fifth comparing means for comparing and outputting a signal when the level of the input luminance signal is larger than the fifth reference value; and a case where a signal is output from the same pixel from the fourth and fifth comparing means. Second video change point detection means for outputting a signal to the second display means, count means for counting the output of the second video change point detection means for one line, count result of the count means, and a sixth reference value 5. The video signal according to claim 1, further comprising: a sixth comparing unit that compares the output of the sixth comparing unit and a holding unit that holds the output of the sixth comparing unit for one line. Detection device. 7. An averaging means for calculating an average of levels of at least effective pixel portions of one line of an input luminance signal, a first comparing means for comparing an output of the averaging means with a first reference value, Comparing the level of the input luminance signal with the second reference value,
Second comparing means for outputting a signal when the level of the input luminance signal is higher than the second reference value; and a third reference value higher than the level of the input luminance signal and the second reference value. And a third comparing means for outputting a signal when the level of the input luminance signal is higher than the third reference value, and a signal for outputting the same pixel from the second and third comparing means. A video changing point detecting means for outputting a signal to the first detecting means, a counting means for counting the output of the video changing point detecting means for one line, and a fourth comparing means for comparing the count result of the counting means with a fourth reference value. The comparing means, the holding means for holding the output of the fourth comparing means for one line, and whether the signal of each line is a signal of a non-image part by both outputs of the first comparing means and the holding means. Non-image area determination means for determining whether or not , The video signal detecting apparatus characterized by comprising a. 8. The video signal detecting apparatus according to claim 7, wherein the averaging means calculates an average value of the levels of one line of the input luminance signal. 9. A display device, wherein the interval between scanning lines of a video signal excluding a signal of a line of a non-image part detected by the video signal detecting device according to claim 1 is extended. A television receiver characterized in that. 10. A method for converting the number of scanning lines of a video signal excluding a signal of a line of a non-image part detected by the video signal detecting device according to claim 1 to display on a display device. Characteristic television receiver.