JPH08163555A - Television signal converter - Google Patents

Abstract

PURPOSE: To maintain the continuity of the fields of TV signals even at the time of thinning out superimposed fields by thinning out the superimposed fields and also adjusting offsets at the time of detecting overlapping fields in first and second fields. CONSTITUTION: Telecine information and delay information by a one frame memory 100 are processed in a subtractor 200, a comparator 500 and an AND gate 501, etc., and an overlapping part in field information is held in a one field holding circuit 600. At the time, a switch 502 is switched by a JK type FF 506 corresponding to VF signals for indicating odd numbered and even numbered fields from a VF generation circuit 508 and the one frame memory is read controlled through a read control circuit 850 controlled by a control signal generation circuit 700 corresponding to the output of the circuit 600. Then, the superimposed part of the first field is thinned out and the prescribed offset is added, the superimposed part of the second field is thinned out and the offset is recovered and field continuity is maintained even when the superimposed parts are thinned out.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a television signal converter, and more particularly, to detecting a television signal written out from the same film frame for a television signal made from a motion picture film and thinning it out. The present invention relates to a television signal converter for efficient encoding or transmission. Further, the present invention is particularly effective when encoding or transmitting an image based on MPEG2 (ISO image compression standard).

[0002]

2. Description of the Related Art When making a television signal (30 Hz / frame) from a movie film (24 Hz / frame) or the like, usually two frames of film correspond to five fields of a television signal with a cycle of 1/12 second. In the 2 to 3 fold-down method that is often used at present, two film frames are made to correspond to five fields of a television signal by writing down odd-numbered film frames to 2 fields and writing down even-numbered film frames to 3 fields. . As a method of detecting such an image signal (hereinafter abbreviated as telecine) converted from a film to a television signal, there is, for example, the method described in Japanese Patent Application No. 2-45408.

FIG. 7 is a block diagram of a television signal conversion apparatus for detecting a redundantly written field from the telecine produced as described above, removing the field, and encoding or transmitting the field. Is shown. The operation of the conventional television signal converter will be described below with reference to the drawings.

In FIG. 7, 10 is an input terminal of the apparatus, and 20
Is an output terminal of the control corresponding to the telecine image, and 30 is an output terminal of the apparatus. Also, 100 is a frame memory, 200 is a subtractor, 3
00 is an absolute value circuit, 400 is a cumulative adder that outputs a cumulative addition result for each field, 500 is a comparator that outputs a comparison result with a threshold value, 600 is a hold circuit that holds data for one field period, and 700 is a telecine. It is a control signal generation circuit that generates a control signal corresponding to an image. Further, 800 is a write control circuit for the memory 900, 850 is a read control circuit for the memory 900, and 900 is a frame memory for storing a video signal. The operation of the conventional television signal conversion device configured as described above will be described.

The telecine signal input from the input terminal 10 of the apparatus is delayed by one frame in the frame memory 100, and the subtracter 200 obtains an interframe difference signal. The difference signal between frames is an absolute value circuit 30
When it becomes 0, it becomes an absolute value, and the cumulative addition unit 400 outputs the cumulative addition result in units of fields. The cumulative addition result is compared with the threshold value by the comparator 500, and when it is larger than the threshold value, it is a field composed of different frames in the original film, and when it is smaller than the threshold value, it is the original film. It is assumed that they are duplicate fields composed of the same frame. The hold circuit 600 holds the result of comparison with the threshold value for one field period, and the control signal generation circuit 7
At 00, a control signal corresponding to the telecine image is generated. On the other hand, the frame memory 900 is a frame memory that prevents duplicate fields from being sent to the next stage. The telecine image (30Hz) is a film image (24Hz).
The frame rate is converted to a frame rate and output from the output terminal 30 of the device. The write control circuit 800 controls write to the frame memory 900, and the read control circuit 850 controls read to the frame memory 900 according to a control signal from the control signal generation circuit 700.

FIG. 8 is a diagram showing conversion of a video signal in the frame memory 900 shown in FIG. The conversion operation of the telecine image will be described below with reference to FIG. The telecine signal input from the input terminal 10 of the device is output in the order of the normal field until the overlap field is detected (fields 1, 2, 3,
Four,). When a duplicate field is detected, it is output to the next stage without transmitting the duplicate field (fields 6, 5, 8, 7). The control signal generation circuit 700 generates a flag (for example, Repeat First Field of MPEG2 standard) indicating whether or not a duplicate field is detected, and sends it to the next stage.

With the above configuration, a television signal conversion device for a telecine image is constructed, and a video signal of a film rate (24 Hz) from which the duplicate fields included in the telecine image are removed is output from the output terminal 30 and synchronized with this. Then, a control signal corresponding to the output image signal from which the duplicate field has been removed is output from the output terminal 20.

[0008]

The conventional television signal conversion apparatus having the above-mentioned structure detects whether or not there is an overlap field by using the inter-frame difference signal of the telecine image. This is an effective method when it is converted regularly. However, in such a configuration, (1) since the thinning is performed immediately when the duplicate field is detected, the continuity of the field of the television signal cannot be maintained every time the duplicate field is detected, and the frame like the MPEG2 standard cannot be maintained. When trying to perform processing from the previous and next fields to the current field in units of, when the even field and the odd field are interchanged as described above, the processing sequence such as the necessity of exchanging the processing order becomes complicated. Had a problem. Also, in such a configuration, (2) the telecine signal is input at a frame rate of 30 Hz, whereas the converted signal has a frame rate of 24 Hz, and the reference clock of the input telecine signal and the output signal Alternatively, there is a problem in that the circuit operation becomes unstable because a separate reference clock for operating the next stage is required.

Further, in such a configuration, since it is always detected whether or not it is a duplicate field, if an error in the duplicate field is once detected due to noise or the like, the duplicate field is detected only by the even-numbered field or the odd-numbered field. Will be continuously detected. For example, when performing processing in units of frames of the television signal as performed in the MPEG2 standard, etc., when one field is continuously sent in this way, There is a problem that the processing cannot be performed in units of frames, and as a result, the encoding or transmission processing fails.

Factors that cause a failure in encoding or transmission processing due to such erroneous detection of duplicate fields include the following.

(3) In the case of an image edited using a VTR or the like with the telecine image as it is, the regular conversion pattern as shown in FIG. Fields may be detected consecutively in even-numbered fields or odd-numbered fields, and as a result, one field will be sent in succession, making it impossible to process in units of frames as in the MPEG2 standard. .

(4) When the frames of the still image are continuous in the telecine image, it is always judged as an overlapping field continuously, and the control flag (TopFieldFir) in the MPEG2 standard is determined.
In st and RepeatFirstField), the pattern becomes uncontrollable and it becomes impossible to continuously perform encoding and transmission.

(5) When an image with a lot of noise is input as a telecine image, if the threshold value for determining whether or not there is an overlapping field is fixed, the difference between the frames with a lot of noise is detected. Since the value is always larger than this threshold value, it is always judged as an independent field, and it is impossible to improve the efficiency of encoding and transmission by reducing the duplicate field.

(6) Further, when the telecine image and the normal television image (frame rate 30 Hz) are mixed and the noise component is changed, it is judged whether or not there is an overlap field. It becomes impossible to determine whether the result is a false detection due to the influence of noise or the frame rate is actually changing. When the duplicate field is erroneously determined as an independent field, the amount of information to be transmitted to the next stage becomes redundant and the independent field is duplicated. If it is erroneously determined that the image quality is significantly deteriorated.

The present invention solves the above problems by (1)
The continuity of the field of the television signal can be maintained even when the duplicate field is detected and thinned out. (2) The reference clock of the input telecine signal and the reference clock of the output signal after conversion can be processed with the same clock. An object is to provide a section signal conversion device.

Further, (3) when the conversion pattern is irregular, (4) when the telecine image includes a still image portion,
(5) When a telecine image with a lot of noise is input, and (6) when a telecine image with a different original frame rate is input, the overlapping field and the independent field are detected stably and based on the MPEG2 standard. It is an object of the present invention to provide a television signal conversion device for efficiently compressing or transmitting an image signal.

[0017]

In order to solve the above problems, in the television signal converter of the present invention, first, the above (1)
With regard to the above problem, when the duplicate field is detected in the first field, it is thinned out, and the first field is offset by one frame period, and when the duplicate field is detected in the second field, it is thinned out. At the same time, the offset for one frame period given to the first field is restored.

With regard to the above problem (2), both the input telecine signal and the converted output signal are operated at a frame rate of 30 Hz, and the first field and the second field are set to 1 respectively.
When it is detected more than once, the output to the next stage is stopped, and the processing of the next stage and the subsequent stages is suspended for the period of the data which is short in time due to the overlap field being thinned.

Regarding the problem of (3) above, the duplicate field detecting means is provided with a means for switching between detection with an even-numbered field and detection with an odd-numbered field, and an even-numbered field and an odd-numbered field. When the duplicate fields are detected once in the even-numbered field and once in the odd-numbered field, respectively.
The configuration is such that the transmission or coding of the next stage is stopped only for one frame period.

Regarding the problem of (4) above, paying attention to the fact that the duplicate field is regularly detected in the regular conversion pattern, whereas the duplicate field is always detected in the still image. The detection means is provided with a means for prohibiting the detection of the duplicate field, and when the duplicate field is detected, the detection of the duplicate field is prohibited only during the period when the independent field originally continues.

With respect to the above problem (5), a means for controlling the threshold value of the duplicate field detecting means is provided so that it can be changed according to the magnitude of the noise component of the television signal. As means for detecting the size of the noise of the television signal, (a) calculate the average value of the luminance component of the television signal, paying attention to the fact that the telecine image has more noise components in a film taken in a dark place. And (b) focusing on the fact that the inter-frame difference value determined as the overlapping field becomes large when there are many noises, and the method based on the change in the inter-frame difference value determined as the overlapping field.

Further, regarding the above-mentioned problem (6), paying attention to the fact that, when the regular film (24 Hz) is regularly converted to the telecine (30 Hz), the overlapping field appears every 5 fields. , A counter that can measure the interval at which overlapping fields appear and a counter that can measure the number of times the overlapping fields appear continuously in 5 field cycles are provided, and only when the overlapping fields in 5 field cycles are detected a predetermined number of times or more in succession. The configuration is such that the detection result of the duplicate field is valid.

[0023]

The present invention has the above-described structure, and firstly, the above (1)
With regard to the problem of (1), when a duplicate field is detected in the first field, it is thinned out and an offset for one frame period is given to the first field, so that the field corresponding to the duplicate field amount thinned out at this time is reduced. Maintains continuity.
Next, when a duplicate field is detected in the second field, it is thinned out and the offset for one frame period already given to the first field is returned to the original value so that the duplicate field amount thinned out at this time is obtained. Maintain the continuity of the corresponding fields.

Next, with regard to the problem (2), when the overlapping fields are culled once for the first field and the second field, the output of data is stopped only for the period when two fields are insufficient. As a result, the consistency of the field number between the input telecine signal and the converted output signal can be ensured and one reference clock can be used.

With regard to the problem of (3) above, the even-numbered field and the odd-numbered field are alternately detected, so that an irregular conversion pattern exists in the telecine image and the even-numbered field is detected. Even if consecutively overlapping fields are included or odd-numbered fields continuously contain overlapping fields, encoding or transmission can always be performed in frame units, and field continuity can be maintained. .

With regard to the problem (4) above, once the duplicate field is detected, the detection of the duplicate field is prohibited only during the period when the independent field continues in the normal conversion pattern. Even when the frame of the still image is included, the conversion patterns can be continuously connected before and after the frame of the still image, and efficient encoding or transmission can be performed.

Next, with respect to the problem (5) above, the magnitude of the noise component of the telecine image is detected by the average value of the luminance signals of the telecine image or the inter-frame difference value of the field which has been judged as an overlapping field. By adopting a configuration in which the threshold value of the duplicate field detecting means is changed based on this detection result, even if a telecine image with a lot of noise is input, the threshold value is automatically set to be high and the detection sensitivity is lowered. Therefore, the duplicate field can be reliably detected without being erroneously detected by noise, and efficient encoding or transmission can be performed.

Further, with regard to the problem of (6) above, when the detection of the duplicate field of 5 field cycles continues for a predetermined number of times or more, the detection result is made effective for the first time. Even if an independent field is mistakenly detected as a duplicate field, it is judged not by prohibiting sending it to the next stage as a duplicate field immediately, but by judging by the periodicity, the information of the independent field is dropped. It can be transmitted or encoded without being lost.

[0029]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A television signal conversion apparatus according to an embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram showing the structure of a television signal conversion apparatus of the present invention relating to the above-mentioned problems (1), (2) and (3), and FIG. 2 is a television signal of the present invention shown in FIG. FIG. 6 is a timing diagram showing the operation of the signal conversion device. In FIG. 1, the same numbers as in FIG. 7 are added to the circuit blocks that operate in the same manner as in FIG. In FIG. 1, 10 is an input terminal of the device, 30 is an output terminal of the device, and 20 and 40.
Is a control signal output terminal.

In the figure, 508 is a VF for generating a field alternation signal (VF) indicating whether the telecine image input from the input terminal 10 is an even-numbered field or an odd-numbered field.
Generating circuit, 502 changeover switch, 503 inverter, 504 and 505
An OR circuit 506 is a JK type flip-flop, and a reference numeral 507 is a one-frame pulse generation circuit which detects a rising edge of an input signal and generates a pulse having a width of one frame period. The operation of the television signal conversion apparatus of the embodiment of the present invention configured as described above will be described below.

The telecine signal input from the input terminal 10 of the apparatus is output by the frame memory 100, the subtractor 200, the absolute value circuit 300, and the cumulative adder 400 as the cumulative addition result in units of fields. The cumulative addition result is compared with the threshold value by the comparator 500, and when it is larger than the threshold value, it is a field composed of different frames in the original film, and when it is smaller than the threshold value, it is the original film. It is assumed that they are duplicate fields composed of the same frame.

On the other hand, in the VF generating circuit 508, the field alternating signal synchronized with the input telecine signal is generated.
3 is input to the AND circuit 501 through the selector 502,
Controls whether to detect an even-numbered field or an odd-numbered field when detecting duplicate fields. AND circuit 50
Nos. 4 and 505 are JK flip-flop 50 depending on whether the field detected as an overlapping field is an even-numbered field or an odd-numbered field.
Entered in 6.

At this time, the output logic of the JK flip-flop 506 is inverted every time the duplicate field is detected, and the selector 502 is switched,
Switches whether to detect the duplicate field with the even field or the odd field. The 1-frame pulse generation circuit 507 is configured to receive a signal from the JK flip-flop 506 and output a pulse having a width of 1 frame, and detects an overlapping field once for each of the even-numbered field and the odd-numbered field. When the rising edge of the output of the JK flip-flop is observed, a pulse having a width of one frame is output and output from the output terminal 40 as a control signal for the next stage.

The overlap field detection signal detected by the AND circuit 501 is held by the hold circuit 600 for one field period,
A control signal generation circuit 700 generates a control signal so as to correspond to a telecine image. On the other hand, in the frame memory 900, the telecine image (30 Hz) is output from the output terminal 30 of the device by thinning the overlapping fields and rearranging the fields by the frame memory to prevent the overlapping fields from being sent to the next stage. . Write control circuit
800 controls writing to the frame memory 900, and the read control circuit 850
Controls the reading to the frame memory 900 according to the control signal from the control signal generation circuit 700.

With this configuration, the output level of the JK flip-flop 506 is inverted every time a duplicate field is detected, and the even-numbered field and the odd-numbered field are always alternately detected. Done. FIG. 2 is a timing chart showing the operation of the television signal conversion circuit of the present invention shown in FIG. The operation of each unit shown in FIG. 1 will be described below with reference to FIG.

Telecine signal input from the input terminal 10 (second
In the figure (a)), in the 1-frame memory 900, the read control circuit 850 rearranges the frames and decimates the duplicate fields according to the detection result of the duplicate fields, resulting in the converted output (FIG. 2 (b)). Is output. In the control signal generation circuit 700 and the 1-frame pulse generation circuit 507, the control signal (TopFieldFir) corresponding to the telecine image is generated.
st and RepeatFirstField) and signals that control the transmission to the next stage
(EN) is generated and output from the output terminals 20 and 40, respectively (Fig. 2 (c)).

With the above configuration, the above problems (1), (2) and
A television signal conversion circuit of the present invention corresponding to (3) is configured, and when an overlapping field is detected in the first field, it is thinned out and an offset for one frame is given to the first field, and the second field is converted into the second field. When the field detects a duplicate field, the field can be thinned out and the offset of the first field which has already been given can be restored to the original value, so that the continuity of the field of the television signal can be maintained.

Further, when the duplicate fields are detected and thinned out once in the first field and the second field respectively, the output can be stopped only for the period of the data reduced by the thinning, and the operation of the apparatus. The clock can be performed only with the same clock as the input telecine signal. Further, even when there is an irregular conversion pattern in which the duplicate fields occur continuously in the even-numbered fields or the odd-numbered fields, the duplicate fields are always detected alternately in the even-fields and the odd-fields, and the even-fields are detected. By prohibiting the signal to the next stage for one frame period when detected once in the odd field, it is possible to always encode or transmit the input telecine signal in frame units.

Next, the second aspect of the present invention corresponding to the above-mentioned problem (4)
An example will be described. FIG. 3 is a block diagram showing the configuration of the television signal converter of the present invention relating to the above-mentioned problem (4). In FIG. 3, the same numbers as in FIG. 7 are added to the circuit blocks that operate in the same manner as in FIG. Further, in FIG. 3, 10 is an input terminal of the device,
30 is an output terminal of the device, 20 is an output terminal of a control signal, and 50 is an input terminal of a control signal. Also, in the figure, 51
Reference numerals 0 and 511 are AND circuits, and 512 is a 2-field width pulse generation circuit which generates a pulse having a 2-field width corresponding to either the rising edge or the falling edge of the input. The operation of the television signal conversion apparatus of the embodiment of the present invention configured as described above will be described below.

The telecine signal input from the input terminal 10 of the apparatus is output by the frame memory 100, the subtractor 200, the absolute value circuit 300, and the cumulative adder 400 as the cumulative addition result in units of fields. The cumulative addition result is compared with the threshold value by the comparator 500, and when it is larger than the threshold value, it is a field composed of different frames in the original film, and when it is smaller than the threshold value, it is the original film. It is assumed that they are duplicate fields composed of the same frame. When a duplicate field is detected, the 4-field width pulse generation circuit outputs a pulse having a 4-field width, and the pulse having a 2-field width passes through the AND circuits 511 and 510 to detect a duplicate field for a 4-field width period. Prohibit The input terminal 50 is supplied with a control signal as to whether the detection of the duplicate field is stopped for a predetermined period.

The overlap field detection signal detected by the AND circuit 510 is held by the hold circuit 600 for one field period.
A control signal generation circuit 700 generates a control signal so as to correspond to a telecine image. On the other hand, the frame memory 900 is a frame memory for preventing duplicate fields from being sent to the next stage.
(30 Hz) is output from the output terminal 30 of the device after thinning the overlapping fields and rearranging the fields. Write control circuit 800
Controls the writing to the frame memory 900, and the read control circuit 850 controls the reading to the frame memory 900 according to the control signal from the control signal generating circuit 700.

With the above configuration, the television signal conversion circuit of the present invention corresponding to the above-mentioned problem (4) is constructed, and every time a duplicate field is detected, detection of the duplicate field is prohibited for four field periods, and a series of Even when still image frames are mixed between moving image frames, the detection cycle of duplicate fields is not disturbed and detection can be performed at the same period as for moving images. Therefore, the control flag (TopFieldFirst) of the MPEG2 standard And Repeat Fie
ldFirst) can be used for encoding or transmission.

Next, the third aspect of the present invention corresponding to the above-mentioned problem (5)
An example will be described. FIG. 4 is a block diagram showing the configuration of the television signal converter of the present invention relating to the above-mentioned problem (5). In FIG. 4, the same numbers as in FIG. 7 are added to the circuit blocks that operate in the same manner as in FIG. Further, in FIG. 4, 10 is an input terminal of the device,
30 is an output terminal of the device, and 20 is an output terminal of a control signal. Further, in the figure, 520 is a field memory, 521 is a de-configured cumulative adder and the like, and a luminance signal average value circuit for measuring the average value of the luminance signal of the input telecine signal, and 522 dynamically changes the threshold value. This is a threshold setting circuit that can be used. The operation of the television signal conversion apparatus of the third embodiment of the present invention configured as above will be described below.

The telecine signal input from the input terminal 10 of the apparatus is output by the field memory 520, the frame memory 100, the subtractor 200, the absolute value circuit 300, and the cumulative adder 400 as cumulative addition results in field units. The cumulative addition result is compared with the threshold value by the comparator 500, and when it is larger than the threshold value, it is a field composed of different frames in the original film, and when it is smaller than the threshold value, it is the original film. It is assumed that they are duplicate fields composed of the same frame.

On the other hand, the telecine signal input from the input terminal 10 is also input to the luminance signal average value circuit 521, and the average value of the luminance signals in the field is calculated here. This brightness signal average value output is input to the threshold value setting circuit 522, and is controlled to set the threshold value low when the brightness signal average value is high and to set the threshold value high when the brightness signal average value is low. .
The overlap field detection signal detected by the comparator 500 is held by the hold circuit 600 for one field period, and the control signal generation circuit 700 generates a control signal corresponding to the telecine image.

On the other hand, the frame memory 900 is a frame memory for preventing duplicate fields from being sent to the next stage, and a telecine image (30 Hz).
Is output from the output terminal 30 of the device by thinning the overlapping fields and rearranging the fields. The write control circuit 800 controls write to the frame memory 900, and the read control circuit 850 controls read to the frame memory 900 according to a control signal from the control signal generation circuit 700.

With the above construction, the television signal conversion circuit of the present invention corresponding to the above-mentioned problem (5) is constructed, and when the average value of the luminance signal is high, the threshold value for judging the overlap field is set high and the luminance is set. When the average value of the signal is low, the threshold for judging overlapping fields can be set low.
It is possible to detect an overlapping field of an input telecine image without being affected by noise, even if the image is dark and has many noises such as when the original film was shot in a dark place.

Next, the fourth aspect of the present invention corresponding to the above-mentioned problem (5)
An example will be described. FIG. 5 is a block diagram showing the configuration of the television signal conversion apparatus of the present invention relating to the above-mentioned problem (5). In FIG. 5, the same numbers as in FIG. 7 are added to the circuit blocks that operate in the same manner as in FIG. Further, in FIG. 5, 10 is an input terminal of the device,
30 is an output terminal of the device, and 20 is an output terminal of a control signal. In the figure, reference numeral 530 is a hold circuit for holding the cumulative addition result for one field period, 531 is an AND circuit, and 522 is a threshold value setting circuit capable of dynamically changing the threshold value. The operation of the television signal conversion apparatus of the fourth embodiment of the present invention configured as above will be described below.

The telecine signal input from the input terminal 10 of the apparatus is output by the frame memory 100, the subtractor 200, the absolute value circuit 300, and the cumulative adder 400 as the cumulative addition result in units of fields. The cumulative addition result is compared with the threshold value by the comparator 500, and when it is larger than the threshold value, it is a field composed of different frames in the original film, and when it is smaller than the threshold value, it is the original film. It is assumed that they are duplicate fields composed of the same frame. Here, the cumulative addition result from the cumulative adder 400 is input to the threshold value setting unit 522 through the hold circuit 530 and the AND circuit 531.

The AND circuit 531 performs control such that only the cumulative addition result when it is determined that the overlap field is sent to the threshold value setting unit 522. The threshold setting unit 522 inputs the cumulative addition result when it is determined that the overlap field is present. When the cumulative addition result is large, the threshold is set high, and when the cumulative addition result is small, the threshold is set. It is controlled to set a small value.

The overlap field detection signal detected by the comparator 500 is held by the hold circuit 600 for one field period, and the control signal generation circuit 700 generates a control signal corresponding to the telecine image. On the other hand, the frame memory 900 is a frame memory for preventing duplicate fields from being sent to the next stage.
(Hz) is output from the output terminal 30 of the device by thinning the overlapping fields and rearranging the fields. The write control circuit 800 controls writing to the frame memory 900, and the read control circuit 850 controls the frame memory 90 according to the control signal from the control signal generation circuit 700.
Read control to 0 is performed.

With the above construction, the television signal conversion circuit of the fourth embodiment of the present invention corresponding to the above-mentioned problem (5) is constructed, and the inter-frame difference value becomes large even in the overlapping field due to the influence of noise or the like. Since the threshold value can be set high even when the telecine image with a lot of noise is input, the duplicate field can be surely detected.

Next, the fifth aspect of the present invention corresponding to the above-mentioned problem (6)
An example will be described. FIG. 6 is a block diagram showing the configuration of the television signal conversion apparatus of the present invention relating to the above-mentioned problem (6). In FIG. 6, the same numbers as in FIG. 7 are added to the circuit blocks that operate in the same manner as in FIG. Further, in FIG. 6, 10 is an input terminal of the device,
30 is an output terminal of the device, and 20 is an output terminal of a control signal. Further, in the figure, 610 is a cycle detection counter for measuring the interval of overlapping fields, 620 is an inverter, and 630 and 640.
Reference numerals 660 and 660 are AND circuits, and 650 is a counting counter that counts only when consecutive overlapping fields at a predetermined interval are detected. The operation of the television signal converter of the fifth embodiment of the present invention constructed as above will be described below.

The telecine signal input from the input terminal 10 of the apparatus is output by the frame memory 100, the subtracter 200, the absolute value circuit 300, and the cumulative adder 400 as the cumulative addition result in units of fields. The cumulative addition result is compared with the threshold value by the comparator 500, and when it is larger than the threshold value, it is a field composed of different frames in the original film, and when it is smaller than the threshold value, it is the original film. It is assumed that they are duplicate fields composed of the same frame. The detection result of the duplicate field is passed through the hold circuit 600,
The cycle detection counter 610 counts the cycle with the previous duplicate field detection result.

The cycle detection counter 610 is constructed so that the output level becomes the Lo level only when the cycle is, for example, 5 fields (when the film of 24 Hz is converted to telecine). Therefore, if the cycle of the overlapping field is not 5 fields, the pulse is output from the AND circuit 640 every time the overlapping field is detected, and the counter 650 is reset. Further, the AND circuit 630 outputs a pulse each time the overlapping field is detected only when the cycle of the overlapping field is 5 fields, and causes the counter 650 to count up.

The counting counter 630 is a counter that counts how many duplicate fields continuously enter in a cycle of every 5 fields, and when counting a predetermined number, the output level is changed from Lo to Hi. At this time, the overlapping field detection result is output from the AND circuit 660, the control signal generation circuit 700 is operated, and the control signal is generated so as to correspond to the telecine image. On the other hand, the frame memory 900 is a frame memory for preventing duplicate fields from being sent to the next stage, and the telecine image (30 Hz) is output from the output terminal 30 of the device by thinning the overlapping fields and rearranging the fields. The write control circuit 800 controls write to the frame memory 900, and the read control circuit 850 controls read to the frame memory 900 according to a control signal from the control signal generation circuit 700.

With the above configuration, the television signal conversion circuit according to the fifth embodiment of the present invention corresponding to the above-mentioned problem (6) is constructed, and when noise is mixed in the original telecine images having different frame rates. Also in the above, the independent field can be reliably determined without being erroneously determined as the duplicate field, and efficient encoding or transmission can be performed.

[0059]

As is apparent from the above embodiments, in the television signal conversion circuit according to the present invention, (1) one field may be offset by one frame period depending on the result of the duplicate field detection. It is possible to maintain the continuity of the field of the television signal even when the overlap field is thinned out by using the means for returning to the.

(2) When the duplicate field is detected and thinned out once for each of the one field and the other field
Since the output of data for one frame period is stopped, the operation clock of the device can be performed by one kind of clock synchronized with the input telecine signal.

(3) The duplicate field detecting means is provided with a means for switching between detection with an even-numbered field and detection with an odd-numbered field, and is configured to detect alternately with an even-numbered field and an odd-numbered field. However, since the output to the next stage is prohibited only for one frame period when the duplicate field is detected once for each of the even-numbered field and the odd-numbered field, an irregular conversion pattern is applied to the telecine image. Even when the character is included, it is possible to always perform coding or transmission processing on a frame-by-frame basis.

(4) Since the duplicate field detection means is configured to prohibit the duplicate field detection for a period following the independent field by a regular regular conversion pattern once the duplicate field is detected, a still image is displayed on the telecine image. Even when the frame of the still image is included, the conversion patterns can be continuously connected before and after the frame of the still image, and efficient encoding or transmission can be performed.

(5) The magnitude of the noise component of the telecine image is detected by the average value of the luminance signal of the telecine image or the inter-frame difference value of the field which has been determined as the overlapping field, and the detection result is used as the overlapping field detecting means. Even when a telecine image with a lot of noise is input, the threshold can be set automatically to lower the detection sensitivity even if a telecine image with a lot of noise is input. The redundant field can be detected without fail, and efficient encoding or transmission can be performed.

(6) By making the detection result valid for the first time when the detection of the overlapping field of 5 field cycles continues more than a predetermined number of times, the independent field is mistaken as the overlapping field due to the change of noise. Even if something is detected, it is not prohibited to immediately send it to the next stage as a duplicate field, but it is judged by looking at the periodicity, so it is transmitted or encoded without losing the information of the independent field. Can be performed, and can be less affected by noise and the like.

As described above, when the television signal conversion circuit according to the present invention is used, the device can be operated with one kind of clock, and data can be always output in units of frames, which is based on the MPEG2 standard. A suitable television signal conversion device can be provided by directly connecting to a device that performs processing for each field in units of such frames. Also, issue (3)
(4) When a television signal conversion circuit according to the present invention corresponding to (5) and (6) is used, a telecine signal containing noise or an irregular conversion pattern is input. Also in this case, it is possible to always detect and thin out the optimum overlapping field, and to output a signal with the continuity of the field as the converted output signal.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of a first embodiment of a television signal conversion circuit according to the present invention.

FIG. 2 is a timing chart showing the operation of each part of the first embodiment of the television signal conversion circuit of the present invention shown in FIG.

FIG. 3 is a block diagram showing the configuration of a second embodiment of the television signal conversion circuit of the present invention.

FIG. 4 is a block diagram showing a configuration of a third embodiment of a television signal conversion circuit of the present invention.

FIG. 5 is a block diagram showing the configuration of a fourth embodiment of the television signal conversion circuit of the present invention.

FIG. 6 is a block diagram showing a configuration of a fifth embodiment of a television signal conversion circuit of the present invention.

FIG. 7 is a block diagram showing a configuration of a conventional television signal conversion circuit.

8 is a timing diagram showing the operation of each part of the conventional television signal conversion circuit shown in FIG.

[Explanation of symbols]

 100 1 frame memory 400 Cumulative adder 506 JFKK 507 1 frame pulse generator 508 VF generator 600 1 field hold 700 Control signal generator 800 Write control 850 Read control 900 1 frame memory

Claims (10)

[Claims] 1. When the number of frames per second of a television signal is larger than the number of frames per second of a signal source, the field of a duplicated television signal is detected and the duplicate field is thinned out for transmission or encoding. In the television signal conversion device that performs
Duplicate field detection means for detecting repeated fields in the input television signal, and storage means capable of storing at least one frame of the input television signal,
And a control unit for controlling the reading of the storage unit based on the detection result of the overlapping field detection unit, wherein the reading of the storage unit is controlled by the first field in the first field of the television frame. When it is detected, the first overlapping field is thinned out, and after the first overlapping field is detected, an offset of one frame is given only to the first field to read out from the storage means and When the second overlapping field is detected in the second field of the section frame, the second overlapping field is thinned out and the offset for one frame given to the first field is restored. And a television signal converter. 2. The first field is an even-numbered field or an odd-numbered field of a television signal, and the second field is an odd-numbered field or a field different from the first field of the television signal. The television signal conversion device according to claim 1, wherein the television signal conversion device is an even-numbered field. 3. When the number of frames per second of the television signal is larger than the number of frames per second of the signal source, the field of the duplicated television signal is detected and the duplicate field is thinned out for transmission or encoding. In the television signal conversion device that performs
A duplicate field detecting means for detecting a field in which the input television signal is repeated, a storage means capable of storing at least one frame of the input television signal, and the aforesaid result based on the detection result of the duplicate field detecting means. And a control means for controlling reading of the storage means, wherein the control of reading by the control means is performed for one frame period when an overlapping field is detected at least once in each of the first field and the second field. A television signal conversion device, characterized in that encoding or transmission of a television signal is stopped to stop processing of a period of data which is short in time due to thinning of the duplicate field. 4. The television signal conversion according to claim 1, wherein the duplicate field detecting means is configured such that even-numbered fields and odd-numbered fields of the input television signal are alternately detected. apparatus. 5. The television signal conversion apparatus according to claim 1, wherein once the duplicate field detecting means detects the duplicate field, the detection is suspended for a predetermined field period from the next field. . 6. The television signal conversion apparatus according to claim 5, wherein a predetermined field period during which the detection of the duplicate field is suspended is manually set. 7. An accumulating means for accumulating and outputting the absolute value of the difference between each field in the input television signal and the field one frame before by the overlap field detecting means, and the cumulative addition. The output of the means is compared with a threshold value every one field period to detect an overlapping field, and the threshold value is an inter-frame difference near the current field of the input television signal. The television signal conversion device according to claim 1, wherein the television signal conversion device is configured to be determined according to the absolute value of 8. The television signal conversion apparatus according to claim 7, wherein the threshold value is set according to the brightness of the luminance signal of the input television signal. 9. When the number of frames per second of the television signal is larger than the number of frames per second of the signal source, the field of the duplicated television signal is detected and the overlapping field is thinned out for transmission or encoding. In the television signal conversion device that performs
Duplicate field detection means for detecting repeated fields in the input television signal, and storage means capable of storing at least one frame of the input television signal,
The storage means includes cycle detection means for determining the periodicity or phase of the detection output of the overlap field detection means, and control means for controlling the reading of the storage means based on the determination result of the cycle detection means. The reading control is performed by thinning out the first overlapping field and detecting the first overlapping field when the first overlapping field is detected in the first field of the television frame.
After the duplicate field is detected, only the first field is detected.
An offset for one frame is given to read from the storage means, and when a second overlapping field is detected in the second field of the television frame, the second overlapping field is thinned and the first field is also removed. 1. A television signal conversion device characterized in that it is configured to restore the offset for one frame given to. 10. When the periodicity or the phase of the period detecting means is disturbed, the period until the periodicity or the phase is fixed again is configured to be transmitted or encoded including the overlapping field. The television signal conversion device according to claim 9, wherein