JP2004096243A - Superposed data extractor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a superposed data extractor which corrects a malfunction of detecting character data due to clock ran-in (CRI) pulses wrong detectable when signals different from closed caption signals are simultaneously superposed on television signals. <P>SOLUTION: A CRI pulse detector 104 is provided for detecting a CRI pulse from binary data extracted from digital signals AD-converted from television (TV) signals, using a slice level taken as a mean value of a maximum and minimum values of the TV signals obtained in a specified range of the horizontal synchronizing signal. The detector 104 detects a change point of the binary data and detects the CRI pulse, based on the values of the binary data at specified timings (two points) from the change point. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a superimposed data extracting device for extracting character data from a closed caption signal superimposed on a TV signal, for example.
[0002]
[Prior art]
Televisions with a screen size of 13 inches or more in North America (hereinafter abbreviated as “TV”) are capable of transmitting text information such as narrations, conversations, broadcast contents, etc., for persons with hearing impairments. , A TV receiver screen. This function is generally called a caption function.
[0003]
The caption decoder built in the TV receiver is particularly called a closed caption decoder. Also, a signal or broadcast generally superimposed on a TV broadcast for a closed caption decoder is called a closed caption.
[0004]
Here, the closed caption signal will be described with reference to FIGS. FIG. 11 is a diagram showing a signal waveform of a TV signal, and FIG. 12 is a diagram showing a data structure of a closed caption signal. The closed caption signal is superimposed on the TV signal. The first field of the TV signal is called field 1 and the next field is called field 2.
[0005]
In FIG. 12, S30 indicates a TV signal of field 1. The signal to be superimposed on the TV broadcast is present in the 10th to 21st character signal superimposable periods from the beginning of the vertical blanking period. In the current system, the closed caption signal exists between the 21st horizontal synchronization signal from the beginning of the vertical blanking period of field 1. The horizontal synchronization signal of field 1 is shown in S31. As shown in the TV composite signal of field 2 of S32, another closed caption signal may exist between the 284th horizontal synchronization signal of field 2 in some cases. The horizontal synchronization signal of field 2 is shown in S33.
[0006]
S34 shows the waveform of the closed caption signal. The closed caption signal includes a clock run-in (hereinafter, abbreviated as “CRI”) signal, a start bit signal, and 16-bit data. After the burst signal, a CRI signal for synchronizing data is provided for seven cycles. Thereafter, a start bit signal is provided by a 2-bit blanking level and 1 bit indicating the start of data, followed by a 16-bit data area.
[0007]
S35 in FIG. 13 shows the breakdown of the 16-bit data. The 16-bit data is composed of a control code for designating the color and location of the character and a character code for indicating the type of the character, and both are transmitted in 7 bits. The remaining one bit is a parity bit for error detection.
[0008]
S36 indicates the information amount of the closed caption signal. As for the information amount, 16 bits (two characters) of data can be transmitted in one field and one field 2 in one frame (for one screen). Since one screen is equivalent to 30 screens, 480 bits (60 characters) of data can be transmitted from 16 bits × 30 times (each field).
[0009]
Next, an example of a generally known closed caption data extraction method will be described. The operation of the conventional circuit will be described with reference to FIGS. FIG. 13 is a diagram showing a configuration of a conventional data extraction device for a superimposed signal, and FIG. 14 is a diagram showing a signal waveform of the conventional data extraction device. FIG. 15 shows an enlarged signal waveform of the CRI pulse signal range in the signal waveform of the data extraction device of FIG.
[0010]
In FIG. 13, a TV signal (analog signal) S50 is applied to an input terminal 100 of the data extraction device.
[0011]
The TV signal S50 propagates to the AD converter 101, and the AD converter 101 extracts superimposed signal data S51 from the TV signal S50 by AD conversion.
[0012]
The superimposed signal data S51 is propagated to the slice level extraction unit 102 and the binary data extraction unit 103.
[0013]
The slice level extracting unit 102 detects the maximum value and the minimum value of the superimposed signal data S51 within a range of a CRI gate signal S52 described later, generates an average value thereof, and extracts a slice level S53. At the gate end position of the CRI gate signal S52, the generated slice level S53 is held. The slice level S53 is transmitted to the binarized data extraction unit 103.
[0014]
The CRI gate generation unit 105 generates a CRI gate signal S52 as a gate pulse by setting the gate start position S59 and the gate end position S60 from the leading edge of the horizontal synchronization signal S54 by the program control unit 106. The CRI gate signal S52 is propagated to the slice level extraction unit 102 and the CRI pulse detection unit 104.
[0015]
The binarized data extraction unit 103 extracts the binarized data S55 by slicing the superimposed signal data S51 obtained from the AD conversion unit 101 at the slice level S53. The binarized data S55 is transmitted to the CRI pulse detection unit 104 and the character data extraction unit 107.
[0016]
The CRI pulse detection unit 104 extracts a change point from “0” to “1” of the binary data S55, and generates a CRI pulse S56 within the range of the pulse of the CRI gate signal S52. The CRI pulse S56 is propagated to the sampling pulse generator 108.
[0017]
The sampling pulse generator 108 generates 19 sampling pulses S57 for data extraction in synchronization with the last pulse signal of the CRI pulse S56. This sampling pulse S57 is propagated to the character data extraction unit 107.
[0018]
The character data extraction unit 107 extracts character data S58 from the binarized data S55 according to the sampling pulse S57.
[0019]
Next, a signal waveform propagating through each block of the data extracting apparatus for a superimposed signal will be described with reference to FIG.
[0020]
S50 shows the waveform of the line on which the closed caption signal is superimposed in the TV signal applied to the data extraction device.
[0021]
S51 shows a digital waveform of a closed caption signal in superimposed signal data extracted by converting an analog signal into a digital signal.
[0022]
S54 shows the waveform of the line on which the closed caption signal is superimposed in the horizontal synchronization signal applied to the data extraction device.
[0023]
In step S52, the line on which the closed caption signal is superimposed rises with a delay of the gate start position S59 from the leading edge of the horizontal synchronization signal S54, and falls with a delay of the gate end position S60 from the leading edge of the horizontal synchronization signal S54. 3 shows a pulse signal waveform.
[0024]
S53 is a signal indicating the average level of the superimposed signal data S51 within the range of the pulse signal of the CRI gate signal S52. The superimposed signal data S51 is sliced at this slice level S53 to extract binary data S55.
[0025]
S56 shows a pulse waveform generated at a change point of the binary data S55 from "0" to "1" within the range of the pulse signal of the CRI gate signal S52.
[0026]
S57 is a sampling pulse. The sampling pulse S57 is an equally spaced synchronization pulse (19 shots) generated with the CRI pulse S56 as a start position. By sampling the binarized data S55 in synchronization with the sampling pulse S57, all 19 bits of the 3 bits of the start bit of the closed caption signal and the 16 bits of the character data S58 are extracted.
[0027]
Next, an operation of generating the sampling pulse S57 from the CRI pulse S56 will be described with reference to FIG.
[0028]
The sampling pulse S57 is an equally spaced synchronization pulse (19 shots) generated with the CRI pulse S56 as a start position. The sampling pulse generation unit 108 resets the start position of the sampling pulse S57 every time the CRI pulse S56 is detected, and generates 19 synchronization pulses. The CRI pulse S56 is a signal generated within the range of the pulse signal of the CRI gate signal S52. Therefore, the sampling pulse S57 is finally generated as a pulse synchronized with the last pulse signal of the CRI pulse S56.
[0029]
That is, the sampling pulse generator 108 generates the sampling pulse S57-1 in synchronization with the first CRI pulse S56-1 detected in the range of the CRI gate signal S52. However, when a newer CRI pulse S56-2 is detected, the generation of a pulse synchronized with the CRI pulse S56-1 is stopped, and the newly detected CRI pulse S56-2 is set as a start position and the CRI pulse S56-2 is started. Is generated in synchronization with the sampling pulse S57-2. Similarly, when a new CRI pulse S56-3 is detected, generation of a pulse synchronized with the CRI pulse S56-2 is stopped, and a sampling pulse S57-3 synchronized with the CRI pulse S56-3 is generated. This operation is repeatedly performed within the range of the pulse signal of the CRI gate signal S52, and the sampling pulse S57-6 synchronized with the finally detected CRI pulse S56-6 is used as a start position to execute the sampling pulses S57-6 to S57-24. Generate 19 pulses. Character data is extracted from the binarized data S55 using the 19 synchronization pulses as a sampling clock.
[0030]
[Problems to be solved by the invention]
However, in the above-described TV signal superimposed data extracting apparatus and character data extracting method using the superimposed data extracting method, a signal having a large phase shift of a horizontal synchronizing signal, a noise having a larger amplitude than a closed caption signal, or a copy guard signal is used. On the other hand, the CRI pulse cannot be detected. For this reason, a sampling pulse for data extraction cannot be generated, and even when the closed caption signal is superimposed, a phenomenon that characters are not displayed on the display screen of the TV receiver is induced.
[0031]
That is, in the generation of the CRI gate signal S52 by the CRI gate generation unit 105, the CRI gate signal S52 follows the phase shift of the horizontal synchronization signal S54 as shown in FIG. For this reason, since the detection position of the CRI pulse S56 by the CRI pulse detection unit 104 changes, the generation position of the sampling pulse for data extraction changes. Since the character data is extracted using the sampling pulse whose generation position has changed, the position of the closed caption signal is shifted, and the character is not displayed on the display screen of the TV receiver.
[0032]
Further, the method of extracting the slice level S53 by the slice level extracting unit 102 reacts to noise or copy guard superimposed on the TV signal S50 as shown in FIG. For this reason, the position of the slice level shifts, and there arises a problem that the CRI pulse S56 cannot be generated or the CRI pulse S56 having a duty ratio of 1: 1 cannot be generated. Also in this case, a phenomenon similar to the phase shift of the horizontal synchronization signal is induced.
[0033]
The present invention solves such a problem and detects a CRI signal due to a phase shift of a horizontal synchronization signal, which can occur when a signal different from a closed caption signal such as noise or copy guard is simultaneously superimposed on a TV signal. It is an object of the present invention to provide a TV signal superimposed data extraction device capable of correcting a malfunction of the slice level extraction due to the deformation of the CRI signal while correcting the malfunction of the TV signal.
[0034]
[Means for Solving the Problems]
In order to achieve the above object, a superimposed data extraction device according to the present invention is a superimposed data extraction device for extracting data superimposed on a television (TV) signal, wherein the superimposed data extraction device performs horizontal synchronization from a digitized TV signal. A slice level extraction unit for extracting a slice level by obtaining an average value of the maximum value and the minimum value within a specific range based on the signal, and using the slice level to obtain two values from the digitized TV signal A binarized data extracting unit for extracting digitized data, a CRI pulse detecting unit for detecting a clock run-in (CRI) pulse which is a synchronization pulse of a closed caption signal from the binarized data, Sampling the binary data to extract character data from the closed caption signal. An extraction unit, wherein the CRI pulse detection unit detects a change point from the first value to the second value in the binary data, and when a first set time has elapsed from the detected change point. The binarized data is the second value, and the binarized data is the first value when a second set time longer than the first set time has elapsed from the change point. In this case, it is determined that a CRI pulse is present from the change point to the second set time.
[0035]
BEST MODE FOR CARRYING OUT THE INVENTION
As described above, in the superimposition data extraction device of the present invention, the CRI pulse detection unit detects a change point from the first value to the second value in the binary data, and detects the first change point from the detected change point. When the set time has elapsed, the binarized data is the second value, and when the second set time longer than the first set time has elapsed from the change point, the binarized data is the second value. If the value is the first value, it is determined that a CRI pulse exists from the change point to the second set time. The first and second values are “1”, for example, when “0” of the binarized data is the first value. Further, for example, “1” may be set to the first value, and the second value may be set to “0”. According to this configuration, when a signal different from the closed caption signal such as noise or copy guard is simultaneously superimposed on the TV signal, the CRI signal can be correctly detected even if a phase shift of the horizontal synchronization signal occurs. A possible superimposed data extraction device can be provided.
[0036]
The superimposition data extraction device according to the present invention is preferably configured such that when the CRI pulse detection unit detects at least two CRI pulses consecutively at a predetermined timing, the slice level of the slice level extraction unit is determined. .
[0037]
According to this preferred configuration, even when a phase shift occurs in the direction in which the horizontal synchronization signal advances with respect to the closed caption signal, the slice level is not determined until at least two CRI pulses are detected. Therefore, even when the horizontal synchronizing signal has the above-described phase shift, data can be accurately extracted from the closed caption signal.
[0038]
Further, in the superimposed data extraction device according to the preferred configuration, when the CRI pulse detection unit does not detect the next CRI pulse at a predetermined timing after detecting one CRI pulse, It is preferable to output a signal for clearing the slice level.
[0039]
The superimposition data extraction device according to the present invention includes a storage unit that stores a slice level obtained by the slice level extraction unit, and a storage unit that stores a CRI pulse when the CRI pulse is not detected by the CRI pulse detection unit. And a controller for supplying the slice level to the binarized data extraction unit.
[0040]
According to this preferred configuration, even if the CRI pulse cannot be detected accurately due to, for example, noise or copy guard superimposed on the TV signal superimposed on the CRI signal portion, the stored slice level can be reduced. By using this, binarized data extraction can be appropriately performed.
[0041]
Hereinafter, specific embodiments of the present invention will be described with reference to the drawings.
[0042]
(1st Embodiment)
One embodiment of a TV signal superimposed data extraction device according to the present invention will be described with reference to FIGS. 1, 2, 3, and 4. FIG. FIG. 1 is a configuration diagram of the superimposed data extraction device according to the first embodiment. FIG. 2 is a diagram illustrating a signal waveform of the superimposed data extraction device according to the first embodiment. FIG. 3 is a diagram showing a signal waveform of the superimposed data extraction device when a phase shift of the horizontal synchronization signal is induced in the superimposed data extraction device of FIG. FIG. 4 is a diagram showing a signal waveform of the CRI pulse detector in the signal waveform of FIG.
[0043]
As shown in FIG. 1, the superimposed data extraction device according to the present embodiment includes an input terminal 100, an AD conversion unit 101, a slice level extraction unit 102, a binary data extraction unit 103, a CRI pulse detection unit 104, and a CRI gate generation. It comprises a unit 105, a program control unit 106, a character data extraction unit 107, a sampling pulse generation unit 108, and a timer counter 109.
[0044]
In FIG. 1, a TV signal S50 is applied to an input terminal 100 of the superimposed data extraction device.
[0045]
The TV signal S50 propagates to the AD conversion unit 101, and the AD conversion unit 101 extracts superimposed signal data S51 from the TV signal S50 by AD conversion. The superimposed signal data S51 is propagated to the slice level extraction unit 102 and the binary data extraction unit 103.
[0046]
The slice level extraction unit 102 detects the maximum value and the minimum value of the superimposed signal data S51 within a range of a CRI gate signal S52 described later, generates an average value thereof, and extracts a slice level S53. At the gate end position of the CRI gate signal S52, the generated slice level S53 is held. The slice level S53 is transmitted to the binarized data extraction unit 103 and the CRI pulse detection unit 104.
[0047]
The CRI gate generation unit 105 generates a CRI gate signal S52 as a gate pulse by setting the gate start position S59 and the gate end position S60 from the leading edge of the horizontal synchronization signal S54 by the program control unit 106. The CRI gate signal S52 is propagated to the slice level extraction unit 102 and the CRI pulse detection unit 104.
[0048]
However, when the slice level determination signal S61 obtained from the CRI pulse detection unit 104 described later is input, the CRI gate generation unit 105 sets the position where the slice level determination signal S61 is generated as the gate end position, and sets the CRI gate signal S52. Generate Thus, when the CRI pulse S56 is detected by the CRI pulse detection unit 104, the CRI gate signal S52 ends. As a result, the extraction of the slice level S53 by the slice level extraction unit 102 stops, and the slice level at the time when the CRI pulse S56 is detected is determined.
[0049]
The binarized data extraction unit 103 extracts the binarized data S55 by slicing the superimposed signal data S51 obtained from the AD conversion unit 101 at the slice level S53. The binarized data S55 is transmitted to the CRI pulse detection unit 104 and the character data extraction unit 107.
[0050]
The CRI pulse detector 104 operates within the range of the pulse of the CRI gate signal S52. The CRI pulse detection unit 104 first extracts a change point pulse S62 of “1” from “0” of the binary data S55, and starts operation based on the extracted change point pulse S62. Next, the CRI pulse detection unit 104 operates the timer counter 109 from the transition point pulse S62 of the binary data S55. When the counter value reaches the CRI high level monitor set value S63, the timer counter 109 generates a CRI high level monitor pulse S65. At the timing when the CRI high level monitor pulse S65 is generated, the CRI pulse detection unit 104 confirms that the binary data S55 is "1". The CRI high-level monitor pulse setting value S63 is set such that the timing at which the CRI high-level monitor pulse S65 is generated is about a quarter of the period of the CRI pulse from the position of the change point pulse S62. .
[0051]
Further, when the count value of the operated timer counter 109 reaches the CRI low-level monitor set value S64 from the transition point pulse S62 of the binary data S55, the CRI pulse detection unit 104 generates a CRI low-level monitor pulse S66. . At the timing when the CRI low level monitor pulse S66 is generated, the CRI pulse detector 104 confirms that the binarized data S55 is "0". The CRI low-level monitor pulse setting value S64 is set such that the timing at which the CRI low-level monitor pulse S66 is generated is about three-quarters of the period of the CRI pulse from the position of the change point pulse S62. .
[0052]
Then, the CRI pulse detection unit 104 determines that “the binary data S55 is“ 1 ”when the CRI high-level monitor pulse S65 is generated, and“ 0 ”when the CRI low-level monitor pulse S66 is generated. Only when the condition (1) is satisfied, the CRI pulse S56 is set to the high level. When the CRI pulse S56 is generated, the CRI pulse detection unit 104 sets the slice level determination signal S61 to high level. The CRI pulse S56 is propagated to the sampling pulse generator 108, and the slice level determination signal S61 is propagated to the CRI gate generator 105.
[0053]
The sampling pulse generation unit 108 generates a sampling clock S67 for extracting data from when the CRI pulse S56 goes high. The character data extraction unit 107 samples the binarized data S55 in synchronization with the sampling clock S67, and detects a start bit composed of a 2-bit blanking level and one bit indicating the start of data. After detecting the start bit, the sampling pulse generation unit 108 generates, as the sampling pulse S57, 16 clocks for thinning out the caption data to 16-bit data. This sampling pulse S57 is propagated to the character data extraction unit 107.
[0054]
The character data extraction unit 107 extracts character data S58 from the binary data S55 in synchronization with the 16 sampling pulses S57.
[0055]
Next, a signal waveform propagating through each block of the superimposed data extraction device according to the first embodiment will be described with reference to FIG.
[0056]
S50 shows the waveform of the line on which the closed caption signal is superimposed in the TV signal applied to the data extraction device.
[0057]
S51 shows a digital waveform of a closed caption signal in superimposed signal data extracted by converting an analog signal into a digital signal.
[0058]
S54 shows the waveform of the line on which the closed caption signal is superimposed in the horizontal synchronization signal applied to the superimposition data extraction device.
[0059]
In S52, the line on which the closed caption signal is superimposed rises after the gate start position S59 elapses from the leading edge of the horizontal synchronization signal S54, and before the gate end position S60 elapses from the leading edge of the horizontal synchronization signal S54. The pulse signal waveform which falls at the position where the slice level determination signal S61 is generated is shown.
[0060]
S53 is a signal (slice level) indicating the average level of the superimposed signal data S51 within the range of the pulse signal of the CRI gate signal S52. The binarized data extracting unit 103 slices the superimposed signal data S51 based on the slice level S53 to extract binarized data S55.
[0061]
S62 shows a pulse signal waveform generated when the binary data S55 first changes from "0" to "1" within the range of the pulse signal of the CRI gate signal S52.
[0062]
In S56, within the range of the pulse signal of the CRI gate signal S52, the binary data S55 is "1" when the CRI high-level monitor pulse S65 described later is generated, and the binary data S55 is generated when the CRI low-level monitor pulse S66 is generated. A pulse waveform that rises only when the coded data S55 is "0" is shown.
[0063]
S61 shows a signal waveform that rises at the same time as the rising of the CRI pulse S56.
[0064]
S67 is an equally-spaced synchronization pulse (sampling clock) generated with the CRI pulse S56 as a start position. The character data extraction unit 107 detects the three start bits of the closed caption signal by sampling the binary data S55 in synchronization with the sampling clock S67.
[0065]
S57 is 16 equally-spaced synchronization pulses (sampling pulses) generated after the start bit is detected. The character data extraction unit 107 extracts 16-bit data of the character data S58 of the closed caption signal by sampling the binary data S55 in synchronization with the sampling pulse S57.
[0066]
Next, the operation of the signal waveform of the CRI pulse detecting unit 104 when the phase shift of the horizontal synchronizing signal S54 is induced as shown in FIG. 16 in the superimposition data extracting apparatus of FIG. 1 will be described with reference to FIG.
[0067]
The CRI gate generation unit 105 generates a CRI gate signal S52 from the leading edge of the horizontal synchronization signal S54 to the gate end position S60 set by the program control unit 106 from the gate start position S59. The horizontal synchronizing signal S54 applied to the superimposition data extraction device has a phase shift in a direction delayed with respect to the closed caption signal. Therefore, the CRI gate generation unit 105 generates the CRI gate signal S52 in the middle of the CRI signal portion of the closed caption signal.
[0068]
However, in the superimposition data extraction device of FIG. 1, the CRI pulse detection unit 104 extracts a change point pulse S62 from “0” to “1” of the binary data S55 from the remaining CRI signal part, and A CRI pulse S56 and a slice level determination signal S61 are output according to a CRI high level monitor pulse S65 and a CRI low level monitor pulse S66 generated at a timing based on S62. The CRI gate generation unit 105 terminates the CRI gate signal S52 according to the slice level determination signal S61, so that the slice level extraction unit 102 determines the slice level S53. Also, the sampling pulse generation unit 108 generates a sampling clock S67 for data extraction based on the CRI pulse S56, and the character data extraction unit 107 detects a start bit based on the generated sampling clock S67. By detecting the start bit, 16 sampling pulses S57 are generated from the sampling pulse generating unit 108, and the character data extracting unit 107 extracts character data S58 in synchronization with the sampling pulse S57.
[0069]
With the above operation, even when the horizontal synchronization signal S54 induces a phase shift, 16-bit data of the character data S58 of the closed caption signal can be correctly extracted.
[0070]
Next, a signal waveform related to the CRI pulse detection unit 104 and an operation of the CRI pulse detection unit 104 among the signal waveforms illustrated in FIG. 2 will be described with reference to FIG.
[0071]
S51 shows a CRI signal waveform of a closed caption signal in superimposed signal data extracted by converting an analog signal into a digital signal.
[0072]
In step S52, the line on which the closed caption signal is superimposed rises after the gate start position S59 elapses from the leading edge of the horizontal synchronization signal S54, and before the gate end position S60 elapses from the leading edge of the horizontal synchronization signal S54. The pulse signal waveform which falls at the position where the slice level determination signal S61 is generated is shown.
[0073]
S53 is a signal indicating the average level of the superimposed signal data S51 within the range of the pulse signal of the CRI gate signal S52. By slicing the superimposed signal data S51 at the slice level S53, binary data S55 is extracted.
[0074]
The CRI pulse detecting unit 104 extracts a change point pulse S62 from “0” to “1” of the binary data S55.
[0075]
Next, the CRI pulse detection unit 104 operates the timer counter 109 from the transition point pulse S62 of the binary data S55. The timer counter 109 generates a CRI high level monitor pulse S65 when the counter value reaches the CRI high level monitor set value S63. The CRI pulse detector 104 confirms that the binarized data S55 is "1" at the generation timing of the CRI high level monitor pulse S65.
[0076]
The CRI pulse detecting unit 104 further generates a CRI low level monitor pulse S65 when the count value of the timer counter 109 operated from the change point pulse S62 of the binary data S55 reaches the CRI low level monitor set value S63. The CRI pulse detection unit 104 confirms that the binarized data S55 is "0" at the generation timing of the CRI low level monitor pulse S65.
[0077]
The CRI pulse detection unit 104 determines that “the binary data S55 when the CRI high-level monitor pulse S65 is generated is“ 1 ”and the binary data S55 when the CRI low-level monitor pulse S66 is generated is“ 0 ”. Only in this case, the CRI pulse S56 is set to the high level.
[0078]
Further, when generating the CRI pulse S56, the CRI pulse detection unit 104 sets the output of the slice level determination signal S61 to a high level.
[0079]
With the above configuration, the superimposed data extraction device according to the first embodiment of the present invention is realized. With this configuration, when a signal different from the closed caption signal such as noise or copy guard is simultaneously superimposed on the TV signal, the CRI signal can be correctly detected even if a phase shift occurs in the horizontal synchronization signal. A superimposed data extraction device can be provided.
[0080]
(Second embodiment)
A second embodiment of the present invention will be described with reference to FIG.
[0081]
The superimposed data extraction device according to the second embodiment of the present invention has the same configuration as the superimposed data extraction device according to the first embodiment (see FIG. 1), but the operation of the CRI pulse detection unit 104 is the same as that of the first embodiment. This is different from the superimposed data extraction device of the first embodiment.
[0082]
The operation of the CRI pulse detection unit 104 of the superimposed data extraction device according to the second embodiment will be described with reference to FIG.
[0083]
In FIG. 5, the CRI pulse detection unit 104 first extracts a change point pulse S62 from “1” to “0” of the binary data S55, and based on the change point pulse S62 extracted from the binary data S55. , Start operation. Next, the CRI pulse detection unit 104 operates the timer counter 109 from the change point pulse S62 of the binary data S55. Then, when the counter value of the timer counter 109 reaches the CRI low level monitor set value S64, the CRI pulse detection unit 104 matches the binary data S55 with the timing of the CRI low level monitor pulse S66 generated from the timer counter 109. Is set to "0". The CRI low-level monitor pulse set value S64 is set such that the timing at which the CRI low-level monitor pulse S66 is generated is about a quarter of the period of the CRI pulse from the position of the change point pulse S62. .
[0084]
Further, when the counter value of the timer counter 109 operated from the change point pulse S62 of the binarized data S55 reaches the CRI high level monitor set value S63, the CRI pulse detection unit 104 generates the CRI high level generated from the timer counter 109. It is confirmed that the binary data S55 is "1" in accordance with the timing of the monitor pulse S65. The CRI high-level monitor pulse setting value S63 is set such that the timing of generating the CRI high-level monitor pulse S65 is about three-quarters of the period of the CRI pulse from the position of the change point pulse S62. .
[0085]
Then, the CRI pulse detection unit 104 determines that “the binary data S55 when the CRI low-level monitor pulse S66 is generated is“ 0 ”and the binary data S55 when the CRI high-level monitor pulse S65 is generated is“ 1 ””. Only in the case of (1), the CRI pulse S56 is set to the high level. When the CRI pulse S56 is generated, the CRI pulse detection unit 104 sets the output of the slice level determination signal S61 to a high level. The CRI pulse S56 is propagated to the sampling pulse generator 108, and the slice level confirmation signal S61 is propagated to the CRI gate generator 105.
[0086]
As described above, the superimposition data extraction device according to the second embodiment can be realized by changing the operation of the CRI pulse detection unit 104 of the superimposition data extraction device according to the first embodiment.
[0087]
(Third embodiment)
FIG. 6 is a configuration diagram of the superimposed data extraction device according to the third embodiment. FIG. 7 is a diagram illustrating an operation of the slice level extraction unit 102 in the superimposed data extraction device according to the third embodiment. FIG. 8 is a diagram illustrating a signal waveform in the superimposed data extraction device according to the third embodiment.
[0088]
6, the CRI pulse detector 104 operates within the range of the pulse of the CRI gate signal S52. The CRI pulse detection unit 104 first extracts a change point pulse S62 from “0” to “1” of the binary data S55, and starts operation based on the change point pulse S62 extracted from the binary data S55. I do. Next, the CRI pulse detection unit 104 operates the timer counter 109 from the transition point pulse S62 of the binary data S55. The timer counter 109 generates a CRI high level monitor pulse S65 when the counter value reaches the CRI high level monitor set value S63. The CRI pulse detector 104 confirms that the binarized data S55 is "1" at the generation timing of the CRI high level monitor pulse S65. Further, when the count value of the timer counter 109 operated from the change point pulse S62 of the binary data S55 reaches the CRI low level monitor set value S64, the timer counter 109 generates the CRI low level monitor pulse S66. The pulse detection unit 104 confirms that the binarized data S55 is "0" at the generation timing of the CRI low level monitor pulse S65. The operation up to this point is the same as in the first embodiment.
[0089]
In the superimposed data extraction device according to the third embodiment, as shown in FIG. 6, a CRI pulse counter 110 connected to the CRI pulse detection unit 104 is provided. The CRI pulse counter 110 determines that “the binary data S55 is“ 1 ”when the CRI high level monitor pulse S65 is generated, and“ 0 ”when the CRI low level monitor pulse S66 is generated. Is checked, the CRI detection pulse S68 generated by the CRI pulse detection unit 104 is counted up or down. The CRI pulse counter 110 outputs a high-level CRI pulse S56 when the CRI detection pulse S68 is detected twice or more consecutively, and at the same time, the CRI pulse detection unit 104 outputs a high-level slice level determination signal. S61 is output. The slice level determination signal S61 is propagated to the CRI gate generation unit 105 and also to the sampling pulse generation unit 108, as in the superimposed data extraction device according to the first embodiment. The sampling pulse generator 108 generates a sampling clock S67 for data extraction from when the slice level determination signal S61 becomes high level. In addition, when the CRI pulse detection unit 104 cannot detect the second time continuously even after detecting the CRI detection pulse S68 once, it generates a slice level clear signal S69 at a timing at which the second time should be detected. This slice level clear signal S69 is propagated to the slice level extraction unit 102.
[0090]
When the slice level clear signal S69 is input, the slice level extracting unit 102 clears the currently held slice level S53, newly detects the maximum value and the minimum value of the superimposed signal data S51, and detects the average value. Is generated to extract the slice level S53.
[0091]
Next, the operation of the slice level extraction unit 102 in the data extraction device according to the third embodiment will be described with reference to FIG.
[0092]
7, F01 indicates the start of processing of the slice level extraction unit 102.
[0093]
F02 is a step of determining whether or not the current position is the slice level extraction start position. The slice level extraction start position indicates the gate start position S59 of the CRI gate signal S52 (see FIG. 8). The slice level extraction unit 102 repeatedly executes this F02 step until the slice level extraction start position is reached. If it is determined that the current position is the slice level extraction start position, the process proceeds to step F03.
[0094]
F03 is a slice level extraction start step in which the maximum value and the minimum value of the superimposed signal data S51 are detected, the average value is generated, and the slice level S53 is extracted. Next, the process proceeds to step F04.
[0095]
F04 is a step of determining whether or not the slice level determination signal S61 is at a high level. The slice level determination signal S61 is a signal output at a high level when the CRI pulse detection unit 104 continuously detects the CRI detection pulse S68 two or more times. If the slice level determination signal S61 is at the low level, the process proceeds to the next F05 step. If the slice level determination signal S61 is at the high level, the process proceeds to an F09 step described later.
[0096]
F05 is a step of determining whether or not the slice level clear signal S69 is at a high level. The slice level clear signal S69 is output in order to clear the slice level S53 at the timing when the second detection is to be performed when the second detection cannot be performed continuously even if the CRI detection pulse S68 is detected once. . If the slice level clear signal S69 is at the low level, the process skips step F06, which is the process of clearing the slice level S53, and proceeds to step F07. If the slice level clear signal S69 is at the high level, the flow shifts to the next F06 step.
[0097]
F06 is processing to clear the slice level S53. The slice level extraction unit 102 clears the currently held slice level S53, clears the maximum value and the minimum value of the superimposed signal data S51, and initializes the data so as to execute the slice level extraction process again. . Next, the process proceeds to step F07.
[0098]
F07 is a step of determining whether or not the current position is the slice level extraction end position. The slice level extraction end position indicates the gate end position S60 of the CRI gate signal S52. If it is not the slice level extraction end position, the flow shifts to step F03 to execute slice level extraction. If the slice level extraction end position has been reached, the process proceeds to step F08.
[0099]
F08 is a process for applying the current slice level because the CRI detection pulse S68 cannot be detected twice or more consecutively until the gate end position S60 set by the program control unit 106. Next, the process proceeds to step F10, where the operation of the slice level extraction unit 102 is terminated.
[0100]
In F09, the slice level determination signal S61 at the time when the CRI detection pulse S68 is detected two or more times in succession generates the slice level S53 at the time of detection of the CRI pulse S56, and holds the slice level S53. Next, the process proceeds to step F10, where the operation of the slice level extraction unit 102 is terminated.
[0101]
Further, a signal waveform in the data extraction device of the third embodiment will be described with reference to FIG.
[0102]
S50 shows the waveform of the line on which the closed caption signal is superimposed in the TV signal applied to the data extraction device.
[0103]
S51 shows a digital waveform of a closed caption signal in superimposed signal data extracted by converting an analog signal into a digital signal.
[0104]
S54 is a horizontal synchronizing signal applied to the data extraction device, and shows a waveform when a phase shift occurs in a direction in which the closed caption signal advances.
[0105]
In step S52, the line on which the closed caption signal is superimposed rises after the gate start position S59 from the leading edge of the horizontal synchronizing signal S54, and rises after the gate end position S60 from the leading edge of the horizontal synchronizing signal S54. 7 shows a pulse signal waveform that falls at the position where the slice level determination signal S61 is generated.
[0106]
S53 is a signal indicating the average level of the superimposed signal data S51 within the range of the pulse signal of the CRI gate signal S52, and the superimposed signal data S51 is sliced by the slice level S53 to extract binary data S55.
[0107]
S62 indicates a pulse signal waveform generated when the binary data S55 first changes from "0" to "1" within the range of the pulse signal of the CRI gate signal S52. Here, since the horizontal synchronizing signal S54 is out of phase with respect to the closed caption signal, the first change point pulse S62-1 is generated by noise or copy guard signal superimposed on the sync position of the TV signal 50. To generate a pulse signal waveform.
[0108]
In S68, within the range of the pulse signal of the CRI gate signal S52, "the binarized data S55 is" 1 "when the CRI high level monitor pulse S65 is generated, and the binarized data is generated when the CRI low level monitor pulse S66 is generated. The signal waveform of the CRI detection pulse generated when S55 confirms "0" is shown. Since the CRI detection pulse S68-1 corresponding to the first transition point pulse S62-1 is not a signal obtained by detecting the CRI signal portion of the closed caption signal, the second CRI detection pulse S68-2 cannot be detected continuously. Therefore, the slice level clear signal S69 is generated at the timing at which the second detection is to be performed, and the currently held slice level S53 is cleared. The slice level extraction unit 102 extracts a new slice level S53, slices the superimposed signal data S51, and extracts binary data S55. The CRI pulse detection unit 104 generates the next change point pulse S62-2. The CRI detection pulse S68 in the change point pulse S62-2 is detected twice consecutively, thereby generating a CRI pulse S56 and a slice level confirmation signal S61. The CRI pulse S56 generates a sampling clock S67 for data extraction in the sampling pulse generator 108. Further, the slice level determination signal S61 causes the CRI gate generation unit 105 to lower the CRI gate signal S52 and determine the slice level S53.
[0109]
The character data extraction unit 107 samples the binarized data S55 in synchronization with the sampling clock S67, and detects a start bit composed of a 2-bit blanking level and one bit indicating the start of data. After detecting the start bit, the sampling pulse generator 108 generates 16 clocks for thinning out the caption data to 16-bit data as the sampling pulse S57. The character data extraction unit 107 extracts character data S58 in synchronization with the sampling pulse S57.
[0110]
As described above, according to the superimposed data extraction device according to the third embodiment, when the horizontal synchronizing signal S54 is out of phase with respect to the closed caption signal, the CRI pulse detection unit 104 outputs the TV signal. Even when the CRI pulse counter 110 outputs the CRI detection pulse S68, the slice level determination signal S61 is not output even if it reacts to noise or copy guard superimposed on the sync or burst position in S50. . Thus, even when the horizontal synchronizing signal S54 has the above-described phase shift, the position of the slice level S53 does not deviate from the position of the closed caption signal, and data can be accurately extracted from the closed caption signal.
[0111]
(Fourth embodiment)
FIG. 9 is a configuration diagram of a superimposed data extraction device according to the fourth embodiment of the present invention. FIG. 10 is a diagram illustrating the operation of the slice level extraction unit 102 in the superimposition data extraction device according to the fourth embodiment.
[0112]
9, the slice level extraction unit 102 detects the maximum value and the minimum value of the superimposed signal data S51 within a range of a CRI gate signal S52 described later, generates an average value thereof, and extracts a slice level S53. At the gate end position S60 of the CRI gate signal S52, the generated slice level S53 is held.
[0113]
The CRI gate generation unit 105 generates the CRI gate signal S52 by setting the gate start position S59 and the gate end position S60 based on the leading edge of the horizontal synchronization signal S54 according to the signal from the program control unit 106. I do.
[0114]
When the CRI pulse S56 is detected by the CRI pulse detector 104, the slice level determination signal S61 is generated, and the CRI gate signal S52 ends. As a result, the extraction of the slice level S53 by the slice level extraction unit 102 is stopped, and the slice level S53 at the time when the CRI pulse S56 is detected is determined. The determined value of the slice level S53 is stored in the storage unit 111 by setting the slice level storage control S70 by the program control unit 106.
[0115]
If the CRI pulse S56 cannot be detected by the CRI pulse detector 104, the slice level determination signal S61 is not generated until the gate end position S60 set by the program controller 106. Therefore, the binarized data extracting unit 103 extracts the binarized data S55 by slicing the superimposed signal data S51 at the gate end position S60 of the CRI gate signal S52 according to the storage slice level S71 stored in the storage unit 111. Will be done.
[0116]
Next, the operation of the slice level extraction unit 102 in the superimposed data extraction device according to the fourth embodiment will be described with reference to FIG.
[0117]
F01 indicates the start of the processing of the slice level extraction unit 102.
[0118]
F02 is a step of determining whether or not the current position is the slice level extraction start position. The slice level extraction start position indicates the gate start position S59 of the CRI gate signal S52. This F02 step is repeatedly executed until the slice level extraction start position is reached. If it is determined that the current position is the slice level extraction start position, the process proceeds to step F03.
[0119]
F03 is a slice level extraction start step in which the maximum value and the minimum value of the superimposed signal data S51 are detected, the average value is generated, and the slice level S53 is extracted. Next, the process proceeds to step F04.
[0120]
F04 is a step of determining whether or not the slice level determination signal S61 is at a high level. The slice level determination signal S61 is a signal output from the CRI pulse detection unit 104, and outputs a high level when the CRI pulse S56 is detected. If the slice level determination signal S61 is at the low level, the process proceeds to the next F05 step. If the slice level determination signal S61 is at the high level, the process proceeds to an F09 step described later.
[0121]
F05 is a step of determining whether or not the slice level clear signal S69 is at a high level. The slice level clear signal S69 clears the slice level S53 at the timing at which the second detection should be performed when the second detection cannot be performed continuously even if the CRI detection pulse S68 is detected once. If the slice level clear signal S69 is at the low level, the process skips step F06, which is the process of clearing the slice level S53, and proceeds to step F07. If the slice level clear signal S69 is at the high level, the flow shifts to the next F06 step.
[0122]
F06 is processing to clear the slice level S53. The currently held slice level S53 is cleared, the maximum value and the minimum value of the superimposed signal data S51 are cleared, and the data is initialized so as to execute the slice level extraction processing again. Next, the process proceeds to step F07.
[0123]
F07 is a step of determining whether or not the current position is the slice level extraction end position. The slice level extraction end position indicates the gate end position S60 of the CRI gate signal S52. If it is not the slice level extraction end position, the flow shifts to step F03 to execute slice level extraction processing. If the slice level extraction end position has been reached, the process proceeds to step F08.
[0124]
The operation up to this point is the same as the operation of the slice level extraction unit 102 in the data extraction device of the third embodiment shown in FIG.
[0125]
In the superimposed data extracting apparatus according to the fourth embodiment, the following processing of step F12 is performed instead of the processing of step F08 shown in FIG. 7, and the processing of step F11 is further added.
[0126]
F12 is a process of applying the storage slice level S71 stored in the storage unit 111 because the CRI detection pulse S68 cannot be detected twice or more consecutively before the gate end position S60 set by the program control unit 106. That is, in step F12, when the CRI pulse S56 cannot be detected within the range of the CRI gate signal S52, the storage section 111 outputs the storage slice level S71 at the time when the CRI pulse S56 was detected in the past. The storage slice level S71 is propagated to the binarized data extraction unit 103, and extracts binarized data S55 from the superimposed signal data S51. Next, the process proceeds to step F10, where the operation of the slice level extraction unit 102 is terminated.
[0127]
F09 applies the slice level S53 at the time of detection of the CRI pulse S56 due to the generation of the slice level confirmation signal S61 at the time when the CRI detection pulse S68 is detected twice or more consecutively, and holds the slice level S53. . Then, the process proceeds to step F11.
[0128]
F11 stores the determined value of the slice level S53 in the storage unit 111 by the slice level storage control S70 in the program control unit 106. That is, the process of step F11 is to store the slice level S53 in the storage unit 111 at the time when the CRI pulse S56 can be detected. Next, the process proceeds to step F10, where the operation of the slice level extraction unit 102 is terminated.
[0129]
As described above, the superimposed data extraction device according to the fourth embodiment includes the storage unit 111, so that the noise and copy guard superimposed on the TV signal S50 as shown in FIG. Even when the slice level is superimposed on the CRI signal portion, the position of the slice level S53 does not shift. Accordingly, it is possible to determine the slice level S53 at a position where the duty of the CRI signal becomes 1: 1.
[0130]
【The invention's effect】
As described above, according to the present invention, a superimposed data extraction device capable of avoiding erroneous detection of a signal superimposed on a TV signal, for example, a CRI pulse of a closed caption signal, which may occur due to a phase shift of a horizontal synchronization signal Can be provided.
[Brief description of the drawings]
FIG. 1 is a configuration diagram of a data extraction device for a superimposed signal according to a first embodiment of the present invention.
FIG. 2 is a signal waveform diagram of the data extraction device according to the first embodiment of the present invention.
FIG. 3 is a signal waveform diagram when a phase shift of a horizontal synchronization signal is induced in the data extraction device of FIG. 1;
FIG. 4 is a signal waveform diagram of a CRI pulse detector in the signal waveform of FIG. 2;
FIG. 5 is a signal waveform diagram of a CRI pulse detection unit of the superimposed signal data extraction device according to the second embodiment of the present invention.
FIG. 6 is a configuration diagram of an apparatus for extracting data of a superimposed signal according to a third embodiment of the present invention.
FIG. 7 is an operation flowchart of a slice level extraction unit in a data extraction device according to a third embodiment of the present invention.
FIG. 8 is a signal waveform diagram in the data extraction device according to the third embodiment of the present invention.
FIG. 9 is a configuration diagram of a data extraction device for a superimposed signal according to a fourth embodiment of the present invention.
FIG. 10 is an operation flowchart of a slice level extraction unit in the data extraction device according to the fourth embodiment of the present invention.
FIG. 11 is a signal waveform diagram of a conventional TV signal applied to the present invention.
FIG. 12 is a configuration diagram of a conventional closed caption signal applied to the present invention.
FIG. 13 is a configuration diagram of a conventional superimposed signal data extraction device.
FIG. 14 is a signal waveform diagram of a conventional superimposed signal data extraction device.
FIG. 15 is an enlarged signal waveform diagram of a CRI pulse signal range in FIG.
FIG. 16 is a signal waveform diagram when a phase shift occurs in a horizontal synchronization signal in a conventional data extraction device.
FIG. 17 is a signal waveform diagram showing a case where noise, copy guard, and the like are superimposed on a CRI signal in a conventional data extraction device.
[Explanation of symbols]
100 input terminal
101 AD converter
102 Slice level extractor
103 Binary Data Extraction Unit
104 CRI pulse detector
105 CRI gate generator
106 Program control unit
107 Character data extraction unit
108 Sampling pulse generator
109 Timer counter
110 pulse counter
111 storage unit
S30 TV signal (field 1)
S31 Horizontal synchronization signal (field 1)
S32 TV signal (field 2)
S33 Horizontal synchronization signal (field 2)
S34 Closed caption signal
S35 16-bit data
S36 Information volume
S50 TV signal
S51 Superimposed signal data
S52 CRI gate signal
S53 Slice level
S54 Horizontal sync signal
S55 Binarized data
S56 CRI pulse
S57 Sampling pulse
S58 Character data
S59 Gate start position
S60 Gate end position
S61 Slice level confirmation signal
S62 Change point pulse
S63 CRI high level monitor set value
S64 CRI low level monitor set value
S65 CRI high level monitor pulse
S66 CRI low level monitor pulse
S67 Sampling clock
S68 CRI detection pulse
S69 Slice level clear signal
S70 Slice level storage control
S71 Memory slice level

Claims (4)

A superimposed data extraction device for extracting data superimposed on a television signal,
From the digitized television signal, a slice level extraction unit that extracts a slice level by obtaining an average value of the maximum value and the minimum value within a specific range based on the horizontal synchronization signal,
A binarized data extracting unit for extracting binarized data from the digitized television signal using the slice level;
A clock run impulse detection unit that detects a clock run impulse that is a synchronization pulse of a closed caption signal from the binary data;
A character data extraction unit that extracts character data from the closed caption signal by sampling the binary data in synchronization with the clock run impulse;
The clock run impulse detection unit detects a change point in the binary data from a first value to a second value, and when a first set time has elapsed from the detected change point, the binary data Is the second value, and when the binarized data is the first value when a second set time longer than the first set time has elapsed from the change point, the change point And determining that a clock run impulse exists from the time t to the second set time. 2. The superimposition data extraction device according to claim 1, wherein when the clock run impulse detection unit detects at least two clock run impulses continuously at a predetermined timing, the slice level of the slice level extraction unit is determined. The clock run impulse detector outputs a signal for clearing a slice level to the slice level extractor when the next clock run impulse is not detected at a predetermined timing after detecting one clock run impulse. An apparatus for extracting superimposed data according to claim 2. A storage unit for storing the slice level obtained by the slice level extraction unit,
2. The control unit according to claim 1, further comprising: a control unit that supplies a slice level stored in the storage unit to the binarized data extraction unit when the clock run impulse detection unit cannot detect a clock run impulse. 3. Superimposed data extraction device.

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