JP3133615B2 - Television receiver - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a television receiver, and more particularly, to a television receiver, for example, which is used for a so-called wide-screen TV, and displays an image obtained from a video signal on a screen having an aspect ratio different from that of an input video signal. The present invention relates to a television receiver for displaying.

[0002]

2. Description of the Related Art As a conventional technique, there is a technique for determining whether a video source has an aspect ratio of 4: 3 or a video source having an aspect ratio other than 4: 3. By using this technique, even a video source having a non-image area above and below the screen, such as a Vista size or a cinemascope size (hereinafter, simply referred to as "cinesco size"), can show a small number of non-image areas.

[0003]

However, since the display mode is switched uniformly regardless of the width of the non-image area, the non-image area remains even after the display mode is switched depending on the width of the non-image area. Or a part of the image is lost. Further, in a video source in which subtitles appear outside the image area, subtitles are not determined because subtitles are not determined.

A specific example will be described. An example of a conventional display mode automatic switching operation will be described with reference to FIG. In FIG. 14, a mode in which the portion from (a) to (h) is displayed on the entire screen (hereinafter, simply referred to as “mode 1”)
It is assumed that there are two display modes, i.e., a mode (hereinafter, simply referred to as "mode 2") in which a portion from (c) to (f) is displayed on a full screen.

[0005] At this time, when the image source is in the image area from (b) to (g) and the image source is in the non-image area from (a) to (b) and from (g) to (h), When the mode is automatically switched, the mode is switched to mode 2 because there is a non-image area. Then, (b) to (c)
And the images of the parts (f) to (g) are lost.

Further, in the case where the image source is in the image area from (d) to (e) and the image source is in the non-image area from (a) to (d) and from (e) to (h), When the automatic switching is performed, the mode is switched to the mode 2 because the non-image area exists. Then, from (c) to (d)
The non-image areas up to and from (e) to (f) are displayed on the screen.

Next, an example of a video source having subtitles will be described. (D) to (e) are image areas, and (e) to (g) are subtitles, and (a) to (d) and (g) to (h) are non-image areas. I do. At this time, if the display mode automatic switching operation is performed, the mode becomes the mode 2 and (c) to (f) are completely displayed on the screen, so a part of the subtitles (from (f) to (g)) is lost. .

[0008] Therefore, a main object of the present invention is to provide a television receiver which can display an image on a screen in a display mode corresponding to each video source.

[0009]

SUMMARY OF THE INVENTION The present invention provides a video source for outputting a television signal and a video signal generated from a video reproducing apparatus, and a video signal level detecting means for detecting a luminance level of the video signal from the video source. Determining a non-image area and a certain area on the display screen based on the output of the video signal level detection means, detecting an image start line and an image end line, and reproducing the image at the video source for a predetermined time. A line detecting means for detecting a fixed image start line and a fixed image end line determined based on the detection output of the start line and the image end line, and the image based on the fixed start line and the fixed end line output of the line detecting means. An image that determines whether the source size is cinemascope size, Vista size, or any other size A source determination unit, wherein the image start line detected by the line detection unit is substantially constant as compared with the confirmed image start line, and the luminance level of the image end line detected by the line detection unit is determined by the determination unit; A subtitle discriminating means for detecting that the video source has changed from a state without subtitles to a state with subtitles when the luminance level of the image end line increases, and an output of the video source determining means and A television receiver includes a display adjustment unit that displays an image on a screen in a display mode uniquely determined for each video source according to an output of a caption determination unit.

[0010]

According to the present invention, an image start line and an image end line are detected by the line detecting means based on the video signal detected by the video signal detecting means. Based on these lines,
The video source determining means determines whether the size of the video source is a Sinesco size, a Vista size, or any other size. When the image start line is constant and the image end line changes in a direction in which the image end line increases, the video source determination unit detects that there is a caption. When detecting that there is a subtitle, the display adjustment unit moves the image upward to prevent a part of the subtitle from being lost. Thereafter, the display adjusting means does not change the display mode regardless of the presence or absence of the caption.

[0011]

According to the present invention, since the video source can be more accurately determined, automatic switching can be realized so that an image can be displayed in a more optimal display mode than before.
Also, since it is possible to detect the presence of subtitles outside the image area,
It is possible to automatically switch to the optimum display mode including not only the image area but also the subtitle part. Further, after detecting that there is a subtitle, the display mode is not changed regardless of the presence or absence of the subtitle. In particular, the display mode is not changed when "subtitles" are changed to "no subtitles", so that the image size does not needlessly switch, and the "subtitles" software automatically switches to the optimal display mode You can enjoy it.

The above objects, other objects, features and advantages of the present invention will become more apparent from the following detailed description of embodiments with reference to the drawings.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The television receiver 10 of this embodiment will be described below as being constituted as a so-called wide TV, but it is needless to say that the invention is not limited to this.
Referring to FIG. 1A, a television receiver 10 of this embodiment includes a selection switch 12. A television signal demodulated by a receiving circuit (not shown) is input from an input terminal 14 to a selection switch 12, and a decoded video (composite video) signal from a video playback device (not shown) such as a video playback device is input to the selection switch 12. Is input from an input terminal 16, a luminance (Y) signal separated by luminance / color (Y / C separation) is input from an input terminal 18, and a color (C) signal separated by Y / C is input to an input terminal 20. Is entered from

The selection switch 12 selects an arbitrary signal from the input signals input by a control signal from a selection switching circuit (for example, the main CPU 30 in this embodiment) such as a channel selection CPU. , And output as a luminance signal and a color signal. Select switch 1
The decoded video signal, such as a television signal or a composite video signal, input to 2 is supplied to a Y / C separation circuit 22 and separated into a luminance signal and a color signal in order to match the output from the selection switch 12. The luminance signal and the color signal from the selection switch 12 are supplied to a video chroma processing circuit 24, where synchronization separation is performed, and a horizontal synchronization signal and a vertical synchronization signal are separated and output.
The signals are converted into R, G, and B signals and output. The R, G, B signals from the video chroma processing circuit 24 are applied to a CRT driving circuit 26, and the CRT 2
8 is driven.

The horizontal synchronizing signal and the vertical synchronizing signal from the video chroma processing circuit 24 are given to the main CPU 30. The main CPU 30 is also supplied with a clock and serial data from an image area detection circuit 42 (described later). The main CPU 30 determines the total number of scanning lines (vertical size) of the video source from the image start line and the image end line (both are described later) included in the serial data, and the number of the scanning line of the video source (vertical center). It is possible to know the presence or absence of an image at the center of the screen. Therefore, as a result of performing various arithmetic processing based on these signals, the main CPU 30 supplies a clock and control signal to the video chroma processing circuit 24 to switch a display mode such as an aspect ratio. Based on the clock and the control signal, the video chroma processing circuit 24 outputs a vertical deflection signal, a horizontal deflection signal, and an S-shaped correction signal. These control signals are supplied to the vertical oscillation circuit 34 and the horizontal oscillation circuit 36 of the deflection circuit 32. The outputs of the vertical oscillation circuit 34 and the horizontal oscillation circuit 36 are respectively connected to the vertical drive output circuit 3
8 and the horizontal drive output circuit 40, the CRT 28 is controlled by the vertical drive output circuit 38 and the horizontal drive output circuit 40, and an image is displayed on the CRT 28.

The main CPU 30 has a ROM 30a.
And a RAM 30b. The ROM 30a stores data for each video source. When the size of the video source is the Cinesco size, the vertical center (the number of scanning lines) is 139 and the vertical size (the number of scanning lines) is such that the image can be displayed on a total of 139 lines from the 70th to 208th scanning lines. , Vertical center data and vertical size data corresponding to these are set. When the size of the video source is the Vista size, the vertical center is 1
The 39th line and the vertical size is 22 lines from the 56th line
In order to display images on a total of 167 lines up to the second line,
Vertical center data and vertical size data corresponding to these are set.

If the video source has subtitles,
Since the image is moved upward (scrolled) by 11 scanning lines, vertical center data is set accordingly. When the size of the video source is 4: 3 image, the vertical center is the 139th line, and the vertical size corresponding to the 139th line is such that the image is displayed on a total of 199 lines from the 39th line to the 237th line. Data and vertical size data are set.

Such vertical center data and vertical size data for each video source are stored in the ROM 30a. The ROM 30a stores predetermined horizontal center data and horizontal size data for each video source. Note that a nonvolatile memory may be used instead of the ROM 30a.

These data are output to the video chroma processing circuit 24 as control signals. Also, R
The subtitle flag is stored in the AM 30b. The subtitle flag is set to “with subtitle” or “without subtitle”. Note that a nonvolatile memory may be used instead of the RAM 30b. Further, the image area detection circuit 42 includes a luminance signal from the selection switch 12, a horizontal synchronization signal and a vertical synchronization signal from the video chroma processing circuit 24, and a main CPU.
A non-image area and an image area are detected based on setting data such as a black level threshold value from 40.

The image area detection circuit 42 is configured, for example, as shown in FIG. Image area detection circuit 4
2 includes input terminals 44, 46 and 48. A luminance signal from the selection switch 12 is input from an input terminal 44, a horizontal synchronization signal from the video chroma processing circuit 24 is input to an input terminal 46, and a vertical synchronization signal from the video chroma processing circuit 24 is input to an input terminal 48. A signal is input.

The luminance signal input to the input terminal 44 is supplied to the LPF 50, and the noise component of the luminance signal is removed. The luminance signal processed by the LPF 50 is A
/ D conversion circuit 52. The horizontal synchronizing signal from the input terminal 46 is supplied to a clamp pulse generating circuit 54, which generates a clamp pulse based on the horizontal synchronizing signal. This clamp pulse is applied to the A / D conversion circuit 52. In the A / D conversion circuit 52, the luminance signal is pedestal clamped, and the luminance signal is converted into a 6-bit digital signal according to the white / black level. The upper 5 bits of the digitally converted luminance signal are used as an image area detection CPU.
56. The image area detection CPU 56 is supplied with a horizontal synchronization signal from the input terminal 46, a vertical synchronization signal from the input terminal 48, and setting data from the input terminal 58. Then, the image area detecting CPU 56
Detects an image area based on input data.

The output of the image area detecting CPU 56 is serially transmitted using two output terminals 60 and 62 and is given to the main CPU 30. Further, a clock based on the vertical synchronizing signal and the horizontal synchronizing signal is output from the image area detecting CPU 56, and this clock is A / A
It is provided to a D conversion circuit 52. Therefore, the A / D conversion circuit 52 performs A / D conversion at the timing of this clock. The image area detection circuit 42 and the main CP
The transmission / reception method with the U30 is not limited to the method described above.

The reason that the upper 5 bits of the digital signal are used is that the lower 1 bit is affected by noise and the like.
This is because it is unstable. Moreover, ± 1 bit is processed as an error, and within the range, it is treated as the same data. Therefore, for example, when (00010X) is used as reference data, (00001X) and (00011X)
X) is determined to be the same as the reference data. here,
X is the sixth bit data, which may be "0" or "1". Note that the data from the A / D conversion circuit 42 need not be 5 bits, and the truncation of the least significant bit may be arbitrary. Also, the error need not necessarily be ± 1 bit.

Such an image area detection circuit 42 is more specifically configured as shown in FIG. Referring to FIG. 2, the luminance signal input from input terminal 44 is an LPF 5
DC cut by the capacitor 64 included in the
The bias is biased to a predetermined value by the resistance division by 6 and 68, and the impedance is converted by the transistor 70.
Then, only a low-frequency component of the luminance signal is extracted by the filter including the coil 72 and the capacitor 74, and the transistor 7
The impedance is converted at 6. LPF by these
50, and only the low-frequency component of the luminance signal is extracted. The LPF 50 is, for example, 200 to 300 so as to eliminate the influence of weak electric field noise and unnecessary pulse noise.
A pass band of about kHz is set.

The output of the LPF 50 is supplied to an IC (for example, manufactured by Sanyo Electric Co., Ltd.) constituting the A / D conversion circuit 52.
LC7480) is input to pin 6. On the other hand, the horizontal synchronizing signal input to the input terminal 46 is input to pin 2 of the clamp pulse generating circuit 54 including an IC (for example, SN74LS123) composed of a shot IC, and the clamp pulse is output from pin 5 to A. It is input to pin 12 of the / D conversion circuit 52.

Here, the clamp pulse generation circuit 54
In synchronization with the horizontal synchronizing signal input to pin 2, a pulse is output from pin 13 and input again to pin 9. The pulse output from the 13th pin is set by a time constant circuit including a resistor 78 and a capacitor 80 connected to the 14th and 15th pins. Then, a pulse set by a time constant circuit including a resistor 82 and a capacitor 84 connected to pins 6 and 7 is output from pin 5 as a clamp pulse. This clamp pulse coincides with the position of the pedestal level in the video signal, and is used for clamping by the A / D conversion circuit 52 so that the level at that position is used as a reference level.

The video signal clamped by the clamp pulse is A / D-converted into a 6-bit digital luminance signal.
The signals are output in order from the higher order bits from the 13th to 18th terminals of the / D conversion circuit 52. The A / D conversion timing clock is supplied to an oscillator (O) connected to pins 27 and 28 as an oscillator of an image area detection CPU 56 (for example, M34225 manufactured by Mitsubishi Electric Corporation).
SC) 86, which is generated by a program based on the clock, and is output from the 12th pin of the CPU 56 for image area detection. And the timing clock is A
The clock is input to pin 20 of the / D conversion circuit 52. This clock is a timing pulse for taking in data.

The upper 5 bits of the 6-bit digital luminance signal correspond to pins 11 and 1 of the CPU 56 for image area detection.
The data is sequentially input to the 0th, 9th, 8th, and 6th pins from the upper bit. Then, an image area detection process, which will be described later, is performed by the image area detection CPU 56, and the clock is transferred from the 24th pin and the serial data is transferred to the main CPU 30 from the 25th pin. The setting data (serial data) from the main CPU 30 is input to pin 26.

In the main CPU 30, the aspect ratio determination processing of the video source is performed based on the data, and the control signal and the clock are converted into the video chroma processing circuit 2
4 given. The video chroma processing circuit 24 outputs a vertical deflection signal, a horizontal deflection signal, and an S-shaped correction signal based on the input signal, and controls the deflection circuit 32. Therefore, the deflection circuit 32 performs a process according to the control signals.

Next, the operation of the television receiver 10 thus configured will be described. First, a television signal or a composite video signal input from the input terminal 14 or 16 is supplied to the Y / C separation circuit 22 via the selection switch 12, and is separated into a luminance signal and a color signal. Then, the luminance signal and the color signal are input to the selection switch 12 again, and one of the signal and the luminance signal or the color signal input from the S terminals (input terminals 18 and 20) is selected and output. Is done.

The luminance signal from the selection switch 12 is
The digital image signal is taken into the image area detection circuit 42, A / D converted at the timing of the horizontal synchronization signal and the vertical synchronization signal, and the image area is detected by the digital video signal. The result is input to the main CPU 30 as serial data. In the main CPU 30, the aspect ratio is determined, and a control signal corresponding to the aspect ratio is supplied to the video chroma processing circuit 24. Here, the horizontal deflection signal is a control signal for adjusting horizontal deflection, the vertical deflection signal is a control signal for adjusting vertical deflection, and the S-shaped correction signal is a control signal for adjusting S-shaped correction of deflection.

Next, the operation of the CPU 56 for detecting an image area will be described. FIG. 3 shows an area of a measurement point (sampling point) on the screen. The vertical direction in FIG. 3 indicates the number of horizontal lines (1) from the leading edge (falling edge) of the vertical synchronization signal.
The horizontal direction indicates the time from the trailing edge (rising) of the horizontal synchronization signal. The shaded area is the area where the video signal is actually captured, and the image area is detected based on the input level of each measurement point.

The operation of the image area detecting CPU 56 will be described below with reference to FIGS. First, in step S1 shown in FIG. 4, a black level threshold serving as a reference for detecting an upper non-image area, a lower non-image area, and the presence or absence of an image is set. This value may be set by the main CPU 30 as setting data (serial data) so as to be variable, or may be set in advance as a fixed value. Assuming black (00000) and white (11111), the black level threshold is, for example, (00100) or (0
0101).

Next, in step S3, a vertical synchronization signal for the first vertical period (first field) is waited for. It waits until a vertical synchronizing signal comes, and when a vertical synchronizing signal comes, it proceeds to step S5. In step S5, the width of the non-image area (black band) at the top of the screen is measured. This measurement operation is performed as a subroutine shown in FIG. In the operation of FIG. 5, h1, h2, h3, and h3 are coincident with the embodiment shown in FIG.
The initial values of h4 are 10 μsec, 21 μsec, and 32, respectively.
μsec, 43 μsec, n1 = 32, n2 = 7
6, α = 2, β = 5, and m = ± 1. But,
It is not limited to these values. H1, h2, h3,
Note that it is not limited to a four point measurement of h4. The same applies to each set value in the subroutine of FIGS.

In step S1a shown in FIG.
It is determined whether a horizontal line has been reached. This is determined by whether or not the image area detecting CPU 56 counts the horizontal synchronizing signal (one output per line) from the leading edge of the vertical synchronizing signal and the count value becomes “31”.
Wait until the n1 horizontal line is reached. If the n1 horizontal line is reached (when the count value becomes "31"), "48" is added to "31", "79" is set in the RAM 56a, and the n1 horizontal line is set. Enter the line point measurement.

First, at step S3a, the h1 point of the n1 horizontal line is measured. At this time, data at a point 10 μsec after the trailing edge of the horizontal synchronization signal is measured. This time is measured based on a clock from the image area detection CPU 56, and the digital data from the A / D conversion circuit 52 is read by the image area detection CPU 56 at the timing of this clock. Next, at step S5a, data at the h2 point is measured, at step S7a, data at the h3 point is measured, and at step S9a, data at the h4 point is measured. In this way, a four-point measurement is performed. In this embodiment, the time difference between the points is 1
1 μsec.

Next, in step S11a, h1
It is determined whether or not all the data at the points .about.h4 are within an error of m bits. For the four points on the same line,
For example, of the 6-bit data after A / D conversion, the upper 5 bits are checked and if they are within ± 1 bit, they are regarded as the same data. If “YES” in the step S11a, it is determined in a step S13a whether or not the data of each point is equal to or less than the set black level threshold. If "YES", the line is determined to be a black band, and the line is stored in the RAM 56a. For example, the case of FIG.

Then, in step S15a, it is determined whether or not the measurement line is less than the n2 horizontal line.
If “YES”, the process proceeds to step S17a. In step S17a, the measurement point is shifted by αμsec. Then, in step S19a, it is determined whether the number of shifts is equal to or more than β times. If “YES”, β = 0 is set in step S21a. If “NO” is determined in the step S19a, β is incremented (β = β + 1) in a step S23a. After the processing in steps S21a and S23a, the process proceeds to step S25a.

In step S25a, it is determined whether two horizontal lines have elapsed. That is, the process waits until two horizontal lines have elapsed. When two horizontal lines have elapsed, the process returns to step S3a, and the above-described processing is repeated. In step S3a, the h1 point is
h1 = h1 + α · β. Therefore, the h1 point is 10 μsec, 12 μsec, 14 μsec, 16
μsec, 18 μsec, and 20 μsec.
The gap between the point and the initial value (21 μsec) becomes smaller.
The same applies to h2, h3 and h4 points.

If "NO" is determined in the step S11a, that is, if there is a different value even at one point as shown in FIG. Further, if the step S13a is "NO", that is, as shown in FIG. 8B, if all points are the same but exceed the black level threshold, it is determined that the point is not a black band. In these cases, the process proceeds to step S27a. Steps S11a and S1
As can be seen from FIG. 3a, the black band is not determined to be a black band even if the black level threshold value is simply attained. When step S15a is "NO", the process also proceeds to step S27a. Step S
At 27a, the width of the black band is determined up to the measurement line determined to be a black band, that is, the measurement line first determined not to be a black band is determined to be an image start line, and the process ends.
Here, the image start line indicates the line from which the image starts in terms of the scanning line, and the image end line (described later) indicates the line in which the image ends in the scan line. Then, the width of the black band is measured at intervals of two horizontal lines for a maximum of 23 lines at the top of the screen, that is, for lines 32 to 76. Then, the measurement point is delayed at intervals of 2 μsec between the measurement lines, and returns to the original position temporally in six measurement line cycles.

When the first measurement line (image start line) which is not a black band is detected, the measurement is terminated there, and in step S7 shown in FIG. 4, the presence or absence of an image at the center of the screen is measured. FIG. 6 shows the processing in step S7.
Is executed. Also in the operation shown in FIG. 6, as shown in FIG. 3, the initial values of h5, h6, h7 and h8 are 10 μsec and 47 μsec, respectively.
, 10 μsec and 47 μsec. Therefore,
Two points are measured per line. And n3
= 80, n4 = 110, n5 = 148 and n6 = 17
8 is set.

In step S1b shown in FIG.
It is determined whether a horizontal line has been reached. The process waits until the n3 horizontal line is reached. When the n3 horizontal line is reached, the process proceeds to step S3b. That is, in step S1b,
The already set count value (7 from the vertical sync signal edge)
9) are counted, the following processing is performed.
The presence or absence of an image at the center of the screen (80 lines to 110 lines and 148 lines to 178 lines) is checked. Prior to this check, the count value ("181") of the next check line is set as in the case of measuring the width of the black band at the top of the screen.

First, the upper center portion of the screen is determined. At this time, only two points of 10 μsec and 47 μsec from the trailing edge of the horizontal synchronization signal are determined. First, h5 point data is measured in step S3b, and h6 point data is measured in step S5b, and the process proceeds to step S7b. Step S7
At b, it is determined whether the measured data is equal to or less than the black level threshold. If “YES”, step S9b
In, it is determined whether or not it is less than n4 horizontal lines.
If "YES", it is determined in step S11b whether two horizontal lines have elapsed. Wait until two horizontal lines elapse, and if two horizontal lines elapse, go to step S
Return to 3b.

If "NO" is determined in the step S7b, that is, if even one point of data exceeds the black level threshold value, it is determined in the step S13b that "there is an image". If “NO” in the step S9b, it is determined that “there is no image” in the step S15b. After the processing of steps S13b and S15b, step S1
Proceed to 7b.

In step S17b, it is determined whether or not an n5 horizontal line has been reached. The process waits until the line n5 is reached, and when the line n5 is reached, a determination is made on the lower side of the center of the screen. The determination method is the same as in the upper part of the screen. That is, in step S19b, data at the h7 point is measured, and in step S21b, h7 points are measured.
Eight points of data are measured. And step S
At 23b, it is determined whether or not the measured data is equal to or less than the black level threshold. If "YES", the process proceeds to step S25b.
In, it is determined whether the measurement line is less than the n6 horizontal line. If "YES", it is determined in step S27b whether two horizontal lines have elapsed, and the process waits until two horizontal lines have elapsed. If two horizontal lines have elapsed, the process returns to step S19b. If "NO" in the step S23b, it is determined that "there is an image" in the step S29b, and if "NO" in the step S25b, it is determined that the "image is absent" in the step S31b, and the process proceeds to the step S33b. In step S33b, the presence or absence of an image at the center of the screen is comprehensively determined, and the process ends.
For example, if there are images both above and below the center of the screen, it is determined that there is an image at the center of the screen, and this information is stored in the RAM 56a.

Here, the upper and lower ANDs
However, this is a setting based on the assumption of the Vista size and the Sinesco size, so that these sizes can be detected accurately. This prevents the screen from becoming longer than necessary due to erroneous detection. Note that the upper and lower ORs may be used if the screen is not lengthened more than necessary. In each measurement line, for example, 10 μm
The data at each point of sec, 12 μsec, 47 μsec, and 49 μsec may be measured. At this time, a shift of 2 μsec between adjacent measurement lines (10 μsec →
12 μsec, 47 μsec → 49 μsec), and returns to the original time in two measurement line cycles.

Then, the process proceeds to a step S9 shown in FIG.
The width of the black band at the bottom of the screen is measured. In this process, FIG.
Is executed. To measure the width of the black band at the bottom of the screen, first, the data at the bottom of the screen is stored in the RAM 56a as a bit image. Then, as described below, it is determined whether the range from 182 lines to 244 lines is a black band every two lines, and the result is represented by a 0/1 determination flag.

In the operation of FIG. 7 as well, the initial values of h9, h10, h11 and h12 are 10 μsec, 21 μsec, 32 μsec and 43 μm, respectively.
Set to sec. Also, n7 = 182, n8 = 244
And α = 2, β = 5, and m = ± 1.
Note that the determination flag is 0 for a black band, and 1 otherwise.

In step S1c shown in FIG.
It is determined whether a horizontal line has been reached. The process waits until the n7 horizontal line is reached. When the n7 horizontal line is reached, the process proceeds to step S3c. In step S3c, h9 point data is measured, in step S5c, h10 point data is measured, and in step S7c, h9 point data is measured.
Data of 11 points is measured, and data of h12 points is measured in step S9c. Then, in step S11c, it is determined whether or not each of the data at the points h9 to h12 is only a difference within m bits. If "YES", it is determined in step S13c whether all the data at the points h9 to h12 are equal to or less than the black level threshold. If “YES”, it is determined as “black belt” in step S15c. Step S1
If any one of 1c and S13c is “NO”, it is determined in step S17c that “image is present”.
After the processing in steps S15c and S17c, in step S19c, the respective determination results are stored in the RAM 56c.
Is stored in

Then, in step S21c, it is determined whether or not the measurement line is less than the n8 horizontal line. “Y
ES ”, the measurement point is shifted by αμsec in step S23c, and in step S25c
It is determined whether or not the number of shifts exceeds β times.
If “YES”, β = 0 is set in step S27c, and if “NO”, β is incremented (β = β + 1) in step S29c, and the process proceeds to step S31c. In step S31c, it is determined whether or not two horizontal lines have elapsed. If two horizontal lines have elapsed, the process waits until two horizontal lines have elapsed.
Return to c. Note that, like step S3a in FIG. 5, in step S3c, the measurement point is set as h9 = h9 + α · β. This is the same in steps S5c to S9c.

If "NO" in the step S21c, in a step S33c, the width of the black belt is obtained by referring to the stored judgment result (judgment flag). That is, in this embodiment, when the data measurement for up to 244 lines is completed, the width of the black band at the bottom of the screen is determined, that is, the image end line is detected and the process ends. For example, if the determination result is as shown in FIG. 9, the area below the 240th line is determined to be a black band.

The following data is obtained by the above processing. a: the width of the black band at the top of the screen (image start line) b: the presence or absence of an image at the center of the screen c: the width of the black band at the bottom of the screen (image end line) Returning to FIG. Is determined. It waits until this vertical synchronizing signal comes, and when a vertical synchronizing signal comes, it proceeds to step S13. In step S13, it is determined whether or not the vertical synchronization signal of the third field has arrived. The process waits until the vertical synchronizing signal comes, and when the vertical synchronizing signal comes, the data of the above-mentioned a to c is transmitted in step S15.

Next, in step S17, it is determined whether or not the vertical synchronization signal of the fourth field has arrived. The process waits until the vertical synchronization signal comes. If the vertical synchronization signal comes, the process proceeds to step S19. In step S19, it is determined whether or not the vertical synchronization signal of the fifth field has arrived, and the process waits until the vertical synchronization signal comes. When the vertical synchronization signal comes, the process returns to step S1.

The above operation is performed every six fields (vertical periods). That is, as shown in FIG. 10, the first field: data measurement, the second field: reserved, the third field: data transmission, the fourth field to the sixth field: reserved.

That is, the data is transmitted to the main CPU 30 as serial data in a cycle of an integral multiple of the vertical synchronization (six times in this embodiment). Therefore, the data sampling cycle is 6 vertical periods (≒ 100 msec)
Becomes Note that the transmission cycle is not limited to this.
Next, when receiving the data, the main CPU 30 operates as follows.

First, in step S31 shown in FIG. 11, it is determined whether or not there is an image in the center of the screen. If "NO" is determined in the step S31, the process ends and a step S31
Is "YES", the flow proceeds to step S33. In step S33, the input data is regarded as valid, and the data is stored as the latest data. The latest data includes the latest image start line and the latest image end line. Then, in step S35, it is determined whether the latest data is within the error range of the buffer data. Here, the buffer data is candidate data that may be determined data, and is data stored in a buffer (not shown). The buffer data includes an image start line and an image end line, and these are hereinafter referred to as a buffer start line and a buffer end line, respectively. That is, the latest image start line and image end line are compared with the buffer start line and buffer end line, respectively. The determination here has an error range of ±, and processing is performed so that even if the data does not completely match, it can be determined that they match. Hereinafter, the same applies.
In this embodiment, the error range is ± 1 bit, but it goes without saying that the present invention is not limited to this.

If "NO" in the step S35, the process proceeds to a step S37. In step S37, the latest data is stored as buffer data, and in step S39, since the latest data was not within the error range of the buffer data, the coincidence counter (not shown) is cleared. Next, in step S41, it is determined whether or not it is already determined that the screen is a 4: 3 screen (no upper and lower black bands). If "YES", the process ends. If "NO", the process proceeds to step S43. In step S43, it is determined whether the buffer start line is smaller than the fixed start line. If "NO", it is determined in step S45 whether or not the buffer end data is larger than the determined end line. If “NO”, the process ends. Here, the fixed data includes a fixed start line and a fixed end line, and the fixed start line and the fixed end line refer to the image start line and the image end line fixed at that time, respectively.

If step S43 is "YES" and step S45 is "YES", it is determined that the buffer data has changed in the direction in which the image becomes larger, and the flow advances to step S47. Step S
The case where “45” is “NO” is a case where the buffer data changes in the direction in which the image becomes smaller. In step S47, since the buffer data has changed in the direction in which the image becomes larger, the NG counter (not shown) is incremented, and the process proceeds to step S49. In step S49,
It is determined whether the NG counter has exceeded the set number of times. If “NO”, the process ends. If “YES”, that is, if the buffer data continues for a set number of times in a direction in which the image becomes larger than the current image, it is determined that the data is unstable, and the 4: 3 screen is displayed. , And the process proceeds to step S51. In step S51, the NG counter is cleared. In step S53, processing for setting 4: 3 screen data, that is, the data in the 4: 3 screen (the image start line and the image end line) are added to the fixed start line and the fixed end line, respectively. ) Is set. Then, in step S55, a display mode setting process is performed in the subroutine shown in FIG. 12, and the process ends.

On the other hand, if step S35 is "YES", the NG counter is cleared in step S57. Then, in a step S59, it is determined whether or not the number of coincidences counter is less than the set number of times. If “NO”, that is, if it is equal to or more than the set number of times, the display mode does not need to be changed, and the process ends. The set number of times is set to, for example, 15 times.

If "YES" in the step S59, the coincidence number counter is incremented in a step S61, and the process proceeds to a step S63. In step S63, it is determined whether or not the number of matches counter has reached the set number. If "NO" in the step S63, the process ends.
If “YES”, it is considered that the change of the video source has been determined, and the process proceeds to step S65. That is, if the image start line and the image end line from the image area detecting CPU 56 are within the error range continuously for the set number of times, those lines (boundary lines) are determined as the determination start line and the determination end line. Approximately 100μsec per time
(6 vertical periods).
The line is determined in 5 seconds. Steps S65 to S6
At 9, the buffer data and the confirmed data are compared.

In step S65, it is determined whether or not the buffer start line is within the error range of the fixed start line. If “YES”, it is determined in step S67 whether or not the buffer end line is smaller than the fixed end line. If “YES” in the step S67, it is determined that the “caption is present” is changed to “no subtitle”, and the process ends without changing the display mode. That is, this is a case where the buffer start line is within the error range of the fixed start line and the buffer end line changes in a direction smaller than the fixed end line. This takes into account that subtitles are often displayed at the bottom of the screen, and that subtitles are not displayed. Therefore, in this case, it is determined that the “with subtitles” software has changed from “with subtitles” to “without subtitles”, and the display mode is not changed.

It should be noted that the same algorithm can be applied to the case where subtitles are displayed above the video. For this purpose, in step S65, it is determined whether or not the buffer end line is within the error range of the confirmed end line. In step S67, it is determined whether the buffer start line has changed in a direction larger than the confirmed start line. Should be determined. If the determinations in steps S65 and S67 are both "YES", it is determined that the status has changed from "with subtitles" to "without subtitles".

Next, if step S67 is "NO", it is determined in step S69 whether or not the buffer end line is within the error range of the fixed end line. If "YES" in the step S69, it is determined that the determined data and the buffer data are within the error range, and the process ends without changing the display mode. in this way,
If the buffer data and the determined data are within the error range, the process ends. This is a process when data different from the confirmed data is temporarily received, and thereafter, the same data as the confirmed data is received. If steps S65 and S69 are "NO", then step S7
Proceed to 1.

In step S71, it is determined whether or not the buffer start line is within the error range of the fixed start line. If "YES", it is determined in step S73 whether or not the buffer end line is larger than the fixed end line. If “YES” in the step S73, in a step S75, the subtitle flag is set to “subtitle exists”. That is, when the buffer start line is within the error range and the buffer end line changes in a direction in which the buffer end line increases, it is determined that "no subtitle" has changed to "with subtitle".

On the other hand, if one of steps S71 and S73 is "NO", the subtitle flag is set to "no subtitle" in step S77. If the subtitle is displayed at the top of the image, it is determined in step S69 whether or not the buffer start line is within the error range of the fixed start line. It is determined whether or not the error is within the range of the error. In step S73, it is determined whether or not the buffer start line is larger than the fixed start line.

After the processing in steps S75 and S77, the flow advances to step S79. That is, when the same buffer data is received continuously for the set number of times or more, and there is no change from “with subtitles” to “without subtitles” and the buffer data is not within the error range of the fixed data, in step S79, the video source Is determined to have changed, and the buffer data is determined as the determined data. Then, step S81
, A display mode setting process shown in FIG. 12 is performed based on the determined data.

In the display mode setting process shown in FIG. 12, the optimal mode for projecting a video source of a cinesco size is the cinesco mode, the optimal mode for projecting a video source having subtitles is the subtitle mode, and the video source of the Vista size is used. Vista mode, the best mode to project
The optimal mode for projecting a video source having an aspect ratio of 4: 3 is referred to as a 4: 3 mode.

In step S101 of FIG. 12, first, the current display mode of the screen is determined. Step S10
In step 1, when it is determined that the current mode is the Vista mode or the Sinesco mode, it is determined in step S103 whether or not there is a caption. As described above, for example, when the image start line is constant and changes in the direction in which the image end line increases, it is determined that there is a caption.
If step S103 is "YES", step S1
At 05, a subtitle mode is set. That is, the display mode is set to the Vista mode, and the vertical center is moved upward by a fixed amount so that the subtitles can be seen. Specifically, the vertical size data is output from the main CPU 30 to the video chroma processing circuit 24 so that the vertical size becomes 167, and the vertical center is 128 (= 13).
9-11) The vertical center data is output so as to be the first one. Also, predetermined horizontal size data and horizontal center data are output. As a result, the image is displayed in the subtitle mode. If the video source has a caption as shown in the left diagram of FIG. 13A, the image is displayed in a caption mode as shown in the right diagram of FIG. Then, the process ends.

On the other hand, if step S103 is "NO", the flow proceeds to step S105. In step S105, it is determined whether the video source is a Sinesco size.
As an example of a criterion for judging a cinesco size, when there is an image in the range from the 64th to 214th scanning lines, and when there is no image area after the 63rd scanning line and the 215th scanning line, the cinesco size is judged. Is done. Step S
If "YES" is determined in step 107, the cinesco mode is set in step S109. Specifically, the vertical size data is output from the main CPU 30 to the video chroma processing circuit 24 so that the vertical size becomes 139, and the vertical center data is output so that the vertical center becomes the 139th. Also, predetermined horizontal size data and horizontal center data are output. As a result, an image is displayed in the Sinesco mode. The video source is Fig. 13 (B)
If it is a Sinesco size as shown in the left diagram of FIG.
The image is displayed in the Sinesco mode as shown on the right side of FIG. Then, the process ends.

On the other hand, if step S107 is "NO", the flow proceeds to step S111. In step S111, it is determined whether the video source is a Vista size. As an example of the criteria for determining the Vista size, the range from the 38th line to the 234th line is an image area, and the 37th scan line and the 235th and subsequent scan lines are non-image areas.
Further, when the size is not the Sinesco size, it is determined to be a Vista size. If “YES” in the step S111, the Vista mode is set in a step S113. Specifically, the vertical size data is output from the main CPU 30 to the video chroma processing circuit 24 so that the vertical size becomes 167 lines, and the vertical center data is output so that the vertical center becomes 139 lines. Also, predetermined horizontal size data and horizontal center data are output. As a result, the image is displayed in the Vista mode. If the video source is a Vista size as shown in the left diagram of FIG. 13C, an image is displayed in a Vista mode as shown in the right diagram of FIG. 13C. Then, the process ends.

If step S111 is "NO",
It is determined that the size is 4: 3, and in step S115,
4: 3 mode is set. Specifically, the main CPU
30 to the video chroma processing circuit 24, the vertical size is 1
The vertical data is output so as to have 99 lines, and the vertical center data is output so as to have the 139th vertical center. Also, predetermined horizontal size data and horizontal center data are output. As a result, an image is displayed in the 4: 3 mode. If the video source is a 4: 3 size as shown in the left diagram of FIG. 13D, an image is displayed in a 4: 3 mode as shown in the right diagram of FIG. 13D. Then, the process ends.

In other words, in the current Vista mode or Cinema mode, it is determined whether the video source has subtitles, and whether the video source is of Sinesco size or Vista size. : Judged to be 3 sizes. When it is determined in step S101 that the current mode is the subtitle mode, in step S117, it is determined whether the video source is 4: 3 size. This is because if it is determined during the subtitle mode whether the video source is of the Cinesco size or the Vista size, the display mode is switched when “subtitles exist” to “no subtitles”.
As an example of a criterion for determining that the video source is 4: 3 size, if the image start line is before the 35th scanning line or the image end line is after the 239th scanning line, it is determined to be 4: 3 size. If step S117 is “YES”, the process proceeds to step S115, and step S117 is “N”.
If "O", the process ends.

If it is determined in step S101 that the current display mode of the screen is the 4: 3 mode, the process proceeds to step S119. In step S119, it is determined whether the video source is a Sinesco size. “YE
If “S”, the process proceeds to step S109, and if “NO”, the process proceeds to step S121.In step S121, it is determined whether the video source is a Vista size.If step S121 is “YES”, step S113 is performed.
And if "NO", end. As described above, when it is determined in step S101 that the current mode is the 4: 3 mode, it is determined whether the video source is the Cinesco size or the Vista size, and it is not determined whether there is a subtitle. This is because the judgment of “with subtitles” is made once when the mode is changed from “without subtitles” to “with subtitles” after being set to the Sinesco mode or Vista mode.
This is because it is determined that

In this embodiment, the video source having a non-image area is mainly a movie, and in consideration of the fact that the size thereof can be roughly divided into two, ie, a Cinesco size and a Vista size, processing is performed. I have. In other words, for video sources that have no image areas above and below the screen, such as a movie, discrimination between the Cinesco size and the Vista size, which was not possible in the past, is realized, and by switching to a display mode suitable for each size. In addition, it is possible to automatically switch the display mode in which image loss is small. This makes it possible to realize more optimal display mode automatic switching than before.

Also, by judging that the video source in which the image start line is constant and the image end line changes in the direction in which the image end line becomes larger is changed from “no subtitle” to “with subtitle”, the image source is changed. It can be detected that there is a subtitle outside the area.

[Brief description of the drawings]

FIG. 1A is a block diagram showing an embodiment of the present invention, and FIG. 1B is a block diagram showing an example of an image area detection circuit.

FIG. 2 is a circuit diagram illustrating an example of an image area detection circuit.

FIG. 3 is an illustrative view showing a sampling area on a screen according to the embodiment;

FIG. 4 is a flowchart showing main operations of an image area detection CPU.

FIG. 5 is a flowchart showing an example of a subroutine for measuring the width of a black band at the top of the screen.

FIG. 6 is a flowchart showing an example of a subroutine for measuring the presence / absence of an image in the center of the screen.

FIG. 7 is a flowchart showing an example of a subroutine for measuring the width of a black band at the bottom of the screen.

FIG. 8 is an illustrative view showing a measurement example of a black band of a horizontal line;

FIG. 9 is an illustrative view showing a relationship between a horizontal line and the presence or absence of an image;

FIG. 10 is an illustrative view showing one example of a transfer format of this embodiment;

FIG. 11 is a flowchart illustrating an example of the operation of the main CPU.

FIG. 12 is a flowchart illustrating an example of a subroutine of a display mode setting process.

FIG. 13 is an illustrative view showing each video source and a display mode corresponding to each video;

FIG. 14 is an illustrative view for explaining a conventional art;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 ... Television receiver 24 ... Video chroma processing circuit 26 ... Drive circuit 28 ... CRT 30 ... Main CPU 30a ... ROM 30b ... RAM 42 ... Image area detection circuit 50 ... LPF 52 ... A / D conversion circuit 54 ... Clamp pulse generation Circuit 56: CPU for image area detection 56a: RAM

Claims (3)

(57) [Claims] A video source for outputting a television signal and a video signal generated from a video reproducing apparatus; a video signal level detecting means for detecting a luminance level of the video signal from the video source; Based on the output, a region having no image and a certain region on the display screen are determined, an image start line and an image end line are detected, and an image start line and an image end line are detected in the video source reproduced for a predetermined time. A line detection means for detecting a fixed image start line and a fixed image end line determined based on the output, the size of the video source being a cinemascope size based on the output of the fixed start line and the fixed end line of the line detection means, A video source determining means for determining whether the size is Vista size or other size; The image start line detected by the line detection means is substantially constant as compared with the confirmed image start line, and the luminance level of the image end line detected by the line detection means is the luminance level of the confirmed image end line When it changes in a direction to become larger, the subtitle discriminating means for detecting that the video source has changed from a state without subtitles to a state with subtitles, an output of the video source determining means and an output of the subtitle determining means A television receiver comprising display adjustment means for displaying an image on a screen in a display mode uniquely determined for each video source in response to the image. 2. The display adjustment unit, when detecting a change from a state without subtitles to a state with subtitles as output by the subtitle discrimination unit, moves the image in an upward direction on a display screen. 2. The television receiver according to 1. 3. The television according to claim 2, wherein, after the image has been once moved upward by the display adjusting means, the display adjusting means does not change the display mode even if the detection output of the subtitle discriminating means changes. Receiver.