CN1189045A - Dual-screen display device and method - Google Patents

Abstract

A dual-picture display device and method for displaying two different groups of NTSC video signals simultaneously on both left and right sides of screen is composed of two tuners for receiving and generating two video signals, two digital circuits for digitizing said two video signals, a control circuit for combining the outputs of said two digital circuits, a D/A converter for converting the resultant digital signals to generate a combined video signal, and a display control circuit for displaying said combined video signal. The control circuit solves the problem of asynchronism of two video signals by using a plurality of methods, so that the two different video signals can be simultaneously displayed on the left side and the right side of a screen.

Description

Dual-screen display device and method

The present invention relates to a video display device and method, in particular to a dual-picture display device and method for simultaneously displaying two video signals on the left and right sides of a screen.

Wide-screen (16: 9) TVs have become more and more popular in the market, but most of the general wide-screen TVs can only display a video picture formed by a video signal, especially when displaying a video frame composed of NTSC (National Television Standard Committee) video signal composed of 4:3 video picture. If this kind of picture is not processed specially, there will be two black areas on the left and right sides of the screen. This kind of picture looks uncomfortable and cannot show the characteristics of wide screen. If a little circuit can be added to display two NTSC video signals on the left and right sides of the wide screen at the same time, then people watching TV can watch TV programs of two different channels at the same time, although there will be some distortion in terms of each video picture , but these distortions are generally acceptable to the eye. However, when two video signals are displayed on the left and right sides of a screen at the same time, asynchronous situations often occur, and these asynchronous situations often cause one of the two video images to drift and become unstable.

Therefore, the main purpose of the present invention is to provide a dual-screen display device and method thereof capable of simultaneously displaying two video signals on the left and right sides of the screen and solving the aforementioned asynchronous problem.

To achieve the above object, the present invention provides a dual-screen display device for displaying a first video signal and a second video signal on the left and right sides of a screen, and the two video signals both include an odd scanning field and An even scanning field, when the odd scanning field and the even scanning field are simultaneously displayed on the screen, a video picture is formed, and the two scanning fields all include a predetermined number of horizontal scanning signals, and the display device includes: (1) A first digital circuit comprising:

(a) a synchronous signal separator for separating the horizontal and vertical synchronous signals of the first video signal;

(b) an analog/digital converter for converting each horizontal scanning signal of the first video signal into a digital signal; and

(c) a row of buffers for storing the digital signal; (2) a second digital circuit comprising:

(a) a synchronizing signal separator for separating the horizontal and vertical synchronizing signals of the second video signal;

(b) an analog/digital converter for converting each horizontal scanning signal of the second video signal into a digital signal;

(c) a field buffer, including a plurality of storage locations, used to sequentially store all horizontal scanning signals of a scanning field of the second video signal after the conversion of digital signals; (3) a control circuit, and the The first and second digital circuits are electrically connected, including:

(a) a synchronous detector, used to detect whether the odd and even scanning fields of the first and second video signals are the same field and generate an output according to the synchronous signals generated by the first and second digital circuits;

(b) a field buffer control device, used to control the storage of digital signals in the field buffer, wherein the digital signal generated in the first predetermined place of the second video signal is sequentially generated from the beginning of the field buffer The position begins to be stored, and the digital signal generated at the second predetermined place of the second video signal is determined according to the output of the sync detector at the position where it starts to be stored in the field buffer so that the first and second video signals Two scanning fields of the signal are displayed on the screen synchronously;

(c) a signal combiner, used to take out the digital signal stored in the line buffer and a digital signal in the field buffer, and then sequentially form a composite digital signal, the digital signal in the field buffer The signal is taken out one by one from the initial position of the field buffer; (4) a digital/analog converter, electrically connected to the control circuit, used to convert the composite digital signal into a composite horizontal scanning signal; and (5 ) a display control circuit, electrically connected to the digital/analog converter, for displaying the synthesized horizontal scanning signal on the screen, so that the first and second video signals can be sequentially displayed on the left and right sides of the screen.

The present invention also provides a double-picture display device for displaying a first video signal and a second video signal on the left and right sides of a screen, and the two video signals both include an odd scanning field and an even scanning field , when the odd scanning field and the even scanning field are simultaneously displayed on the screen, a video picture is formed, and the two scanning fields each include a predetermined number of horizontal scanning signals, and the display device includes: (1) a first digital circuit, include:

(a) a synchronous signal separator for separating the horizontal and vertical synchronous signals of the first video signal;

(b) an analog/digital converter for converting each horizontal scanning signal of the first video signal into a digital signal, and

(c) a row of buffers is used to store the digital signal; (2) a second digital circuit, comprising:

(a) a synchronizing signal separator for separating the horizontal and vertical synchronizing signals of the second video signal;

(b) an analog/digital converter for converting each horizontal scanning signal of the second video signal into a digital signal;

(c) a field buffer, including a plurality of storage locations, used to store digital signals generated after conversion of all horizontal scanning signals of a scanning field of the second video signal from its starting position in sequence; (3 ) a control circuit electrically connected to the first and second digital circuits, comprising:

(a) a synchronous detector, used to detect whether the odd and even scanning fields of the first and second video signals are the same field and generate an output according to the synchronous signals generated by the first and second digital circuits;

(b) a field buffer control device, used to control the output of the digital signal in the field buffer, wherein the digital signal of the first predetermined field of the second video signal stored in the field buffer is sequentially obtained from the field The starting position of the buffer begins to output, and the digital signal of the second predetermined field of the second video signal is determined according to the output of the synchronous detector from the position of sequentially outputting from the field buffer so that the first two scan fields of the first and second video signals can be simultaneously displayed on the screen;

(c) a signal combiner for taking out digital signals stored in said line buffer and taking out a digital signal from said field buffer under the control of said field buffer control means to form a composite digital signal; ( 4) a digital/analog converter electrically connected to the control circuit for converting the composite digital signal into a composite horizontal scanning signal; and (5) a display control circuit electrically connected to the digital/analog conversion and a device for displaying the synthesized horizontal scanning signal on the screen, so that the first and second video signals can be sequentially displayed on the left and right sides of the screen.

The present invention also provides a double-picture display method for displaying a first video signal and a second video signal on the left and right sides of a screen, wherein the two video signals both include an odd scanning field and an even scanning field field, when the odd scanning field and the even scanning field are simultaneously displayed on the screen, a video frame is formed, and the two scanning fields all include a predetermined number of horizontal scanning signals. The method includes the following steps:

(1) separating the synchronization signal of the first video signal;

(2) separating the synchronous signal of the second video signal;

(3) judging whether the scanning fields of the first and second video signals are the same field and generating an output by synchronous signals separated by the first and second video signals;

(4) converting each horizontal scanning signal of the first video signal into a digital signal and storing the digital signal in a line buffer;

(5) converting each horizontal scanning signal of each scanning field of the second video signal into a digital signal;

(6) The digital signal of the second predetermined field of the second video signal is stored sequentially from the starting position of a field buffer, and the field buffer includes a plurality of storage locations for storing the digital signal of the second video signal A digital signal generated after conversion of all horizontal scanning signals of a scanning field;

(7) Determine the initial storage position of the digital signal of the second predetermined field of the second video signal in the field buffer according to the output of the (3) step, and start from the initial storage position sequentially stored in the field buffer so that the second video signal can be displayed on the screen synchronously with the first video signal;

(8) outputting a digital signal in the line buffer and a digital signal in the field buffer and sequentially synthesizing a combined digital signal, and sequentially outputting the digital signal in the field buffer from its initial position;

(9) converting the combined digital signal into a combined horizontal scanning signal;

(10) Displaying the combined horizontal scanning signal on the screen, so that the first and second video signals can be sequentially displayed on the left and right sides of the screen.

The present invention also provides a dual-screen display method for displaying a first video signal and a second video signal on the left and right sides of a screen, wherein the two video signals each include an odd scanning field and an even scanning field. A scanning field, when the odd scanning field and the even scanning field are simultaneously displayed on the screen, a video frame is formed, and the two scanning fields all include a predetermined number of horizontal scanning signals. The method includes the following steps:

(1) separating the synchronization signal of the first video signal;

(2) separating the synchronous signal of the second video signal;

(3) judging whether the scanning fields of the first and second video signals are the same field and generating an output by synchronous signals separated by the first and second video signals;

(4) converting each horizontal scanning signal of the first video signal into a digital signal and storing the digital signal in a line buffer;

(5) converting each horizontal scanning signal of each scanning field of the second video signal into a digital signal;

(6) The digital signal of each scanning field of this second video signal is stored in sequence from the initial position of a field buffer, and this field buffer includes a plurality of storage positions, is used for storing the digital signal of this second video signal A digital signal generated after conversion of all horizontal scanning signals of a scanning field;

(7) The digital signal stored in the line buffer and a digital signal of the field buffer are taken out and synthesized into a combined digital signal sequentially; the digital signal of the first predetermined field of the second video signal is obtained by the start of the field buffer and the digital signal of the second predetermined field of the second video signal is then determined according to the output of the (3) step to determine its sequential output position from the field buffer so that the first and two scan fields of the second video signal are synchronously displayed on the screen;

(8) converting the combined digital signal into a combined horizontal scanning signal;

(9) Displaying the combined horizontal scanning signal on the screen, so that the first and second video signals are sequentially displayed on the left and right sides of the screen.

The double-picture video display device and method of the present invention can simultaneously display two different video signals on both sides of a screen, and even if the two video signals are not synchronized, a stable double-picture display can be obtained.

FIG. 1 is a functional block diagram of a dual-screen display device of the present invention.

Figure 2 shows a video frame of two video signals.

FIG. 3 is an odd scanning field and an even scanning field of the two video signals shown in FIG. 2 .

FIG. 4 is a combined video picture of the two video signals shown in FIG. 2 .

FIG. 5 shows the situation where the odd scanning field and the even scanning field of two video signals are received asynchronously.

FIG. 6 is a combined video picture of the two video signals shown in FIG. 5 .

FIG. 7 shows an even field storage method used to solve the out-of-sync problem shown in FIG. 6. FIG.

FIG. 8 is a combined video picture of the two video signals shown in FIG. 7 .

FIG. 9 shows an odd field storage method used to solve the out-of-sync problem shown in FIG. 6. FIG.

FIG. 10 is a combined video picture of the two video signals shown in FIG. 9 .

FIG. 11 shows an even field output method used to solve the out-of-sync problem shown in FIG. 6. FIG.

FIG. 12 shows an odd field output method used to solve the out-of-sync problem shown in FIG. 6. FIG.

See Figures 1 through 4. FIG. 1 is a functional block diagram of a dual-screen display device 10 of the present invention. FIG. 2 shows video frames of two video signals V1 and V2. The video signal V1 includes a plurality of horizontal scanning signals m1 to m8, and the video signal V2 includes a plurality of horizontal scanning signals n1 to n8. For the convenience of illustration, the video signals V1 and V2 are used to simulate two NTSC video signals. 3 shows odd and even scanning fields of video signals V1 and V2, ie, M1/M2 and N1/N2. Each odd or even scanning field includes a predetermined number (4) of horizontal scanning signals. The display device 10 is used to display the two video signals V1 and V2 on the left and right sides of the screen. FIG. 4 shows a combined video frame 60 of the two video signals V1 and V2 generated by the display device 10 .

Display device 10 comprises: a tuner 14 is used for receiving wireless signal from antenna 12 and produces a first video signal V1; A tuner 16 is used for receiving radio signal from antenna 12 and produces a second video signal V2; Digital circuit 18 is used to digitize the first video signal V1; a second digital circuit 26 is used to digitize the second video signal V2, and a control circuit 38 is used to combine the outputs of the first and second digital circuits 18 and 26, a digital A/A converter 46 is used to convert the output of control circuit 38 into a combined video signal, and a display control circuit 48 is used to display the combined video signal on screen 50 .

The first digital circuit 18 includes: a synchronous signal separator 20, which is used to separate the vertical and horizontal synchronous signals of the first video signal V1; Each of the horizontal scanning signals m1 to m8 is converted into a digital signal; and a line buffer (1ine buffer) 24 is used to store the digital signal converted from a horizontal scanning signal.

The second digital circuit 26 includes: a synchronous signal separator 28, which is used to separate the vertical and horizontal synchronous signals of the second video signal V2; an analog/digital converter 30, which is used to scan each horizontal line of the second video signal V2 The signals n1 to n8 are converted into a digital signal; and a line buffer 32 which contains a plurality of storage locations for sequentially storing all the digital signals of any field (N1 or N2) of the second video signal V2. The field buffer (field buffer) 32 is a first in first out buffer (first in/first out buffer).

The control circuit 38 is electrically connected to the first digital circuit 18 and the second digital circuit 26 for controlling the storage and output of the digital signals generated by the first and second digital circuits 18 and 26 . It includes a sync detector 40 , field buffer control means 42 and a signal combiner 44 .

The synchronous detector 40 is used for judging whether the scanning fields of the first and second video signals V1 and V2 are synchronous (same field or distinct field) and produces an output.

The field buffer control means 42 is used to control how the digital signal will be stored in the field buffer 32 . One of the scanning fields of the second video signal V2 (N1 or N2) is stored in the field buffer 32 from the start position of the field buffer 32 in sequence, and another scanning field of the second video signal V2 ( The digital signal that N2 or N1) produces is then determined according to the output of synchronous detector 40 the position that its field buffer 32 begins to store, so that the two scanning fields (m1/m2 of the first and second video signal V1 and V2 ) and (N1/N2) can be displayed on the screen 50 synchronously.

The signal combiner 44 is used to take out a digital signal stored in the line buffer 24 and a digital signal in the field buffer 32, and then sequentially form a composite digital signal, and the digital signal in the field buffer 32 is generated by the field buffer 32. The starting position of the starting position is taken out one by one.

The reason why the first digital circuit 18 uses a line buffer 24 to store a digital signal, and the second digital circuit 26 uses a field buffer 32 to store all digital signals in a scanning field is because the control circuit 38 will continuously The digital signal stored in line buffer 24 is combined with a corresponding digital signal stored in field buffer 32 into a composite digital signal, which is then converted into a composite horizontal scanning signal and displayed on screen 50 . Since each digital signal stored in the line buffer 24 will be taken out by the control circuit 38 immediately and combined into a composite digital signal, the first digital circuit 18 does not need to use a field buffer to convert the first video signal V1 All digital signals of a field are stored.

A digital/analog (D/A) converter 46 is electrically connected to the signal combiner 44 of the control circuit 38 for converting the synthesized digital signal generated by the signal combiner 44 into a synthesized horizontal scanning signal. The display control circuit 48 is electrically connected to the digital/analog converter 46, and is used to display the composite horizontal scanning signal on the screen 50, so that the first and second video signals V1 and V2 can be displayed on the left and right sides of the screen 50 in sequence. side.

The device 10 also includes a display control switch 52, which includes an output terminal 54 electrically connected to the display control circuit 48; a first input terminal 58 electrically connected to the digital/analog converter 46 for receiving the composite horizontal scanning signal; And a second input terminal 56 for receiving the first video signal V1. The switch 52 is used to selectively connect one of the two input terminals as the input terminal of the display control circuit 48, so that the dual-screen display device 10 can display the first and second video signals V1 and V2 on the left and right sides of the screen 50 in sequence. side, or display the first video signal V1 on the screen alone. This design enables the first video signal V1 to be directly displayed on the screen 50 without digital processing by the first digital circuit 18 , which makes the picture quality appear more vivid due to the absence of errors generated by digital processing.

The first video signal V1 shown in FIG. 2 includes two black horizontal scanning signals m2 and m3, and the second video signal V2 also includes two black horizontal scanning signals n2 and n3. Each video signal includes an odd scanning field and an even scanning field. When the odd scanning field and the even scanning field are simultaneously displayed on a screen, a video frame can be formed. When transmitting video signals, odd scanning fields and even scanning fields are transmitted alternately. For example, the two fields of the first video signal V1 are transmitted or received in the following order:

M1, M2, M1, M2, M1, M2, . . . and the two scanning fields N1/N2 of the second video signal V2 are also transmitted or received in the same manner. Because the video signals V1 and V2 are generated by different TV stations, the first and second digital circuits 18 and 26 often have out-of-synchronization when receiving the odd and even scanning fields of the video signals V1 and V2. For example, the digital signal stored in the line buffer 24 of the first digital circuit 18 belongs to the odd scan field (M1), but the corresponding digital signal stored in the field buffer 32 of the second digital circuit 26 may belong to the even scan field. field (N2). When the display video signals V1 and V2 are on the left and right sides of the screen, if the scanning field is not synchronized properly, it will have a serious impact on the display of the video image. Figures 3 and 4 illustrate the procedure and results of combining two synchronized video signals, while Figures 5 and 6 illustrate the problems caused by combining two asynchronous video signals.

Referring to FIG. 3 and FIG. 4, these two figures are used to illustrate the process and result of combining and displaying two synchronized video signals V1 and V2. FIG. 3 shows that the odd and even scanning fields M1/M2 of the first video signal V1 are received synchronously with the odd and even scanning fields N1/N2 of the second video signal V2. When combining and displaying the odd scan fields M1 and N1, the digital signals m1 and n1 are combined into a composite digital signal m1-n1 and displayed on the first scan line (m1-n1) of the video frame 60. Then the rest of the digital signals are formed into digital signals m3-n3, m5-n5, m7-n7 one by one and displayed on the third, fifth and seventh scanning lines of the video image 60. After the odd scan field M1/N1 is combined and displayed, the even scan field M2/N2 is also combined into four synthetic digital signals m2-n2, m4-n4, m6-n6, m8-n8 in the same way, and displayed On the second, fourth, sixth and eighth scanning lines of the video frame 60 . Comparing FIG. 4 with the video frame of FIG. 2, it can be seen that the four black digital signals m2, m3, n2 and n3 are all displayed in correct positions.

Please refer to Figure 5 and Figure 6. FIG. 5 shows the situation of asynchronously receiving odd and even scanning fields and even scanning fields of two video signals V1 and V2. FIG. 6 is a combined video frame 62 of the two video signals shown in FIG. 5 . In FIG. 5, the odd and even scanning fields M1/M2 of the first video signal V1 are combined with the even and odd scanning fields N2/N1 of the second video signal V2 for display. When combining and displaying the odd scanning field M1 and the even scanning field N2, four synthesized digital signals m1-n2, m3-n4, m5-n6 and m7-n8 are composed and displayed on the first, third, Five, seven scanning lines. Then the even scanning field M2 and the odd scanning field N1 will be combined into four synthetic digital signals m2-n1, m4-n3, m6-n5 and m8-n7 and displayed on the second, fourth, sixth and eighth of the video frame 62 scan line. From the graphic content and code on the right side of the video frame 62, it can be clearly found that the displayed positions of the black horizontal scanning signals n2 and n3 are not correct. In fact, in the right half of the video picture 62, all the digital signals (n1, n3, n5, n7) of the odd scanning field N1 of the second video signal V2 are displayed at the positions where the even scanning field N2 should be displayed, while the even scanning field N1 All the digital signals (n2, n4, n6, n8) of field N2 are displayed at the positions where odd field N1 should be displayed. This false display problem is caused by combining and displaying two out-of-sync video signals V1 and V2.

The present invention proposes four methods to solve this problem: Fig. 7 and Fig. 8 show a kind of even field storage method, Fig. 9 and Fig. 10 show a kind of odd field storage method, Fig. 11 shows a kind of even field output method, However, FIG. 12 shows an odd field output method.

Figure 7 and Figure 8 show a storage method and result of an even field. FIG. 7 shows an even field storage method for solving the out-of-sync problem shown in FIG. 6 , and FIG. 8 shows a combined video frame 64 of the two video signals V1 and V2 shown in FIG. 7 . This method is to shift all the digital signals of the even scan field N2 from the normal storage position in the field buffer 32 (stored sequentially from the initial position of the field buffer 32) to form a new even scan. Field N2', and all digital signals for odd field N1 are stored in field buffer 32 in their normal storage locations. The contents of even field N2' and odd field N1 are shown in FIG. 7 . The video frame 64 shown in FIG. 8 is composed of four fields M1/N2' and M2/N1. As can be seen from FIG. 8, although the digital signal n8 of the even scanning field N2 is discarded when stored in the field buffer 32, all digital signals n1 to n7 of the second video signal V2 displayed on the right side of the video picture 64 are all digital signals n1 to n7 according to Arranged in order. On the actual screen, a horizontal scanning signal at the lower edge of the video picture is usually difficult to be seen by the naked eye, so this method of using storage displacement can effectively solve the above-mentioned asynchronous problem.

The embodiment of the even scanning field storage method disclosed in the first method in the display device 10 is as follows: when storing the digital signal of the even scanning field N2 of the second video signal V2 in the field buffer 32, if the synchronous detector The output of 40 shows that the scanning fields of the first and second video signals V1 and V2 are the same field, then the field buffer control device 42 controls the input of the field buffer 32 so that the digital signal of the even scanning field N2 is transmitted by the field buffer 32 The position of the next digital signal from the start position is sequentially stored in the field buffer 32 . If the output of the sync detector 40 shows that the fields of the first and second video signals V1 and V2 are different fields, the field buffer control means 42 controls the input of the field buffer 32 so that the digital signal of the even field N2 is The initial position of the field buffer 32 is stored in the field buffer 32 in sequence.

When the digital signal of the even scanning field N2 of the second video signal V2 is stored in the field buffer 32, if the output of the sync detector 40 shows that the scanning fields of the first and second video signals V1 and V2 are the same field, that is Said that the even scan field N2 is combined and displayed asynchronously with the first video signal V1 when output to the control circuit 38, because although the first and second video signals V1 and V2 are stored in the line buffer 24 in the same field and in the field buffer 32, but the digital data taken out by the control circuit 38 from the field buffer 32 at this time is the digital data temporarily stored in the field buffer 32 of the second video signal V2 in the last scanning field, but the control circuit 38 The digital data taken out from the line buffer 24 is the digital data of the first video signal V1 stored in the line buffer 24 at this time, thus resulting in asynchronously displayed scanning fields, just as described in FIGS. 5 and 6 situation. That is why the field buffer controller 42 starts to implement the first method to solve the out-of-sync problem when the output of the sync detector 40 shows that the fields of the first and second video signals V1 and V2 are the same field.

Figures 9 and 10 show the second method and the results it produces. FIG. 9 shows an odd field storage method for solving the asynchronous problem shown in FIG. 6, and FIG. 10 shows a combined video frame 66 of the two video signals V1 and V2 shown in FIG. The second method is to discard the first digital signal n1 of the odd scanning field N1, and then start storing the second digital signal n3 and subsequent digital signals (n5, n7) from the initial position of the field buffer 32 to A new odd scanning field N1' is formed, and all digital signals of the even scanning field N2 are stored sequentially from the initial position of the field buffer 32 . The storage method of the odd scan field N1 can be completed by the field buffer control device 42. When storing the odd scan field N1 to the field buffer 32, the field buffer control device 42 controls the input of the field buffer 32 so that the first digital signal n1 is not stored in the field buffer 32, but the second digital signal n3 and subsequent digital signals (n5, n7) will be stored sequentially from the initial position of the field buffer 32, and Fig. 9 shows an even scanning field N2 and the contents of the new odd field N1'.

The video frame 66 shown in FIG. 10 is formed by combining the four fields M1/N2 and M2/N1' shown in FIG. It can be seen from FIG. 10 that although the digital signal n1 of the odd scanning field N1 of the second video signal V2 is discarded when stored in the field buffer 32, all digital signals of the second video signal V2 displayed on the right side of the video picture 66 N2 to n8 are arranged in order. On the actual screen, a horizontal scanning signal at the upper edge of the video image is usually difficult to be seen by the naked eye, so this method of using storage displacement can effectively solve the above-mentioned asynchronous problem.

The embodiment of the odd scanning field storage method disclosed by the second method in the display device 10 is as follows: when storing the digital signal of the odd scanning field N1 of the second video signal V2 in the field buffer 32, if the synchronous detector 40 The output of the first and second video signals V1 and V2 shows that the scanning fields are the same field, then the field buffer control device 42 controls the input of the field buffer 32 so that the first digital signal n1 of the odd scanning field N1 is not stored. The second digital signal n3 and subsequent digital signals (n5, n7) are stored in the field buffer 32 sequentially from the initial position. If the output of the sync detector 40 shows that the fields of the first and second video signals V1 and V2 are different fields, the field buffer control means 42 will control the input of the field buffer 32 so that the digital signal of the odd field N1 The data are stored in the field buffer 32 sequentially from the start position of the field buffer 32 .

When the digital signal of the odd scanning field N1 of the second video signal V2 is stored in the field buffer 32, if the output of the sync detector 40 shows that the scanning fields of the first and second video signals V1 and V2 are the same field, that is The odd scan field N1 will be asynchronously combined and displayed with the first video signal V1 when output to the control circuit 38 , just like the situation described in FIG. 5 and FIG. 6 . This is why the field buffer controller 42 starts to implement the second method to solve the out-of-sync problem when the output of the sync detector 40 shows that the fields of the first and second video signals V1 and V2 are the same field.

Above-mentioned first kind and second kind of method are to solve above-mentioned out-of-sync problem by controlling odd scan field N1 and even scan field N2 storage position in field buffer 32, when output digital signal by field buffer 32, these two In the first method, all the digital signals of the odd scanning field N1 and the even scanning field N2 are output from the initial position of the field buffer 32 . The following third and fourth methods solve the above-mentioned asynchronous problem by controlling the output modes of the odd field N1 and the even field N2 in the field buffer 32 . In these two methods, all the digital signals of the odd scanning field N1 and the even scanning field N2 are stored from the initial position of the field buffer 32 .

When implementing the following two retrieval and storage methods, the functions of the field buffer control device 42 and the signal combiner 44 shown in FIG. 1 will be changed. Here the function of the field buffer control device 42 is to control the output of the odd and even scanning field digital signals of the second video signal V2 according to the output of the synchronous detector 40 so that the two scanning fields N1 and N2 of the second video signal can be are appropriately displayed on the screen 50. The signal combiner 44 is used to take out the digital signal in the line buffer 24 of the first digital circuit 18 and take out a corresponding signal in the field buffer 32 of the second digital circuit 26 under the control of the field buffer control device 42. digital signal, and then sequentially combine the two digital signals to form a combined digital signal.

Before the control circuit 38 takes out the first group of digital data from the field buffer 32, if the output of the sync detector 40 shows that the scanning fields of the first and second video signals V1 and V2 are the same field, that is to say, the data stored in the field buffer 32 The scan field of the first digital signal in the starting position is the same field as the digital signal stored in the line buffer 24, so the digital signals stored in the field buffer 32 will start from the starting position of the field buffer 32 in order is fetched and displayed on the screen 50 synchronously with the digital signal in the line buffer 24. If the output of the sync detector 40 shows that the fields of the first and second video signals V1 and V2 are different fields, that is to say the field of the first digital signal stored in the start position of the field buffer 32 is different from the field stored in the field buffer 32. The digital signal in the line buffer 24 is a different field, then the field buffer control device 42 controls the output of the field buffer 32 in different ways so that the first and second video signals V1 and V2 can be displayed on the screen synchronously. 50 on. The third and fourth methods will be illustrated in FIGS. 11 and 12 .

FIG. 11 shows an even field output method for solving the out-of-sync problem shown in FIG. 5 and FIG. 6 . In this method, the digital signals (n2, n4, . Signals are then output sequentially from the start position of the field buffer 32 in a normal manner. FIG. 11 shows the output sequence of this method, and the resulting composite video frame is exactly the same as the video frame 64 shown in FIG. 8 .

The even scan field output method disclosed in the third method is implemented in the display device 10 as follows: when outputting the digital signal of the even scan field N2 stored in the field buffer 32, if the output of the synchronous detector 40 The scan fields that show the first and second video signals V1 and V2 are different fields, and the field buffer control device 42 controls the output of the field buffer 32 so that the digital signal of the even scan field N2 is delayed by one digit by the field buffer 32. The time output of the signal. If the output of the sync detector 40 shows that the fields of the first and second video signals V1 and V2 are the same field, the field buffer control means 42 controls the output of the field buffer 32 so that the digital signal of the even field N2 is divided by the field. The starting position of the buffer 32 starts to be output sequentially.

FIG. 12 shows an odd field output method used to solve the out-of-sync problem shown in FIG. 5 and FIG. 6 . This method discards the first digital signal n1 stored in the odd scanning field N1 in the initial position of the buffer 32 and starts to output sequentially from the digital signal n3 at the next position of the initial position and subsequent digital signals, and The digital signals of the even scanning field N2 stored in the field buffer 32 are sequentially output from the initial position of the field buffer 32 in a normal manner. FIG. 12 shows the output sequence of this method, and the resulting composite video frame is exactly the same as the video frame 66 shown in FIG. 10 .

The even field output method disclosed in the fourth method is implemented in the display device 10 as follows: when outputting the digital signal of the odd field N1 stored in the field buffer 32, if the output of the sync detector 40 shows The scanning fields of the first and second video signals V1 and V2 are different fields, then the field buffer control device 42 controls the output of the field buffer 32 to make the field buffer 32 convert the digital signal at the next position of the initial position n3 and subsequent digital signals are output sequentially. If the output of the sync detector 40 shows that the fields of the first and second video signals V1 and V2 are the same field, the field buffer control means 42 controls the output of the field buffer 32 so that the digital signal of the odd field N1 is divided by field The start position of the buffer 32 starts to be sequentially output.

The above descriptions are only preferred embodiments of the present invention, and those skilled in the art can make various modifications and changes without departing from the spirit and scope of the present invention, so they should be covered within the scope of the appended claims.

Claims (20)

1, a kind ofly is used for showing that one first vision signal and one second vision signal are in the double-image display device of the and arranged on left and right sides of a screen, this two vision signal all includes a strange scanning field and an even scanning field, when being shown in this screen simultaneously, this strange scanning field and even scanning field just can form a video pictures, this two scanning field all includes the horizontal time-base of a predetermined number, described display unit comprises: (1) first digital circuit comprises:

(a) a synchronous demultiplexer is used for separating the level and the vertical synchronizing signal of first vision signal;

(b) analog/digital converter is used for converting each horizontal time-base of first vision signal to a digital signal; And

(c) line buffer is used for storing this digital signal; (2) second digital circuits comprise:

(a) a synchronous demultiplexer is used for separating the level and the vertical synchronizing signal of second vision signal;

(b) analog/digital converter is used for converting each horizontal time-base of second vision signal to a digital signal;

(c) field buffer comprises a plurality of memory locations, is used for storing successively the digital signal that all horizontal time-bases of the one scan field of this second vision signal are produced after changing; (3) one control circuits are electrically connected with described first and second digital circuit, comprising:

Whether strange, the even scanning field that (a) synchronous detector, the synchronizing signal that is used for producing according to first and second digital circuit detect described first and second vision signal is homologous field and produces an output;

(b) a field buffer control device, be used for controlling the storage of digital signal in the described field buffer, the digital signal that first predetermined location of wherein said second vision signal produces is to begin storage by the original position of this field buffer successively, the digital signal that second predetermined location of described second vision signal produces then be according to the output of this synchronizing indicator determine its in position that this field buffer begins to store so that two scanning fields of this first and second vision signal be shown in synchronously on this screen;

(c) signal combiner, be used for taking out the digital signal and the interior digital signal of described field buffer that are stored in the described line buffer, form a synthetic digital signal then successively, the digital signal in the described field buffer is begun to take out one by one by the original position of this field buffer; (4) one digital/analog converters are electrically connected on described control circuit, are used for converting described synthetic digital signal to a synthetic horizontal time-base; Reach (5) one display control circuits and be electrically connected on described digital/analog converter, be used for described synthetic horizontal time-base is shown on the described screen, so that this first and second vision signal can be shown in the left and right sides of described screen successively.

2, the described double-image display device of claim 1 also comprises a display control switch, and this switch includes an output and is electrically connected on described display control circuit; One first input end is electrically connected on described digital/analog converter, is used for receiving described synthetic horizontal time-base; And one second input be used for receiving described first vision signal, described display control switch is used to select to connect a end in this two input as the input of described display control circuit, thereby makes described double-image display device show that successively described first and second vision signal is in the left and right sides of described screen or show that separately this first vision signal is on described screen.

3, double-image display device as claimed in claim 1, wherein said first predetermined field is a strange scanning field and described second predetermined field is an even scanning field, when digital signal that should the idol scanning field is stored in described field buffer, if the output of this synchronizing indicator shows that described first and second vision signal is a homologous field, then this field buffer control device control this field buffer input so that digital signal that should the idol scanning field begin to deposit in successively from the next position of this field buffer original position successively.

4, double-image display device as claimed in claim 1, wherein said first predetermined field is an even scanning field and described second predetermined field is a strange scanning field, when the digital signal of this strange scanning field of storage during in this field buffer, if the output of described synchronizing indicator shows that described first and second vision signal is a homologous field, then described field buffer control device control described field buffer input so that the second digit signal of described strange scanning field and described thereafter digital signal begin to deposit in successively from this field buffer original position.

5, double-image display device as claimed in claim 1, wherein in the digital signal of described second predetermined field of storage during in described field buffer, if it is different that the output of described synchronizing indicator shows described first and second vision signal, then described field buffer control device control this field buffer input so that the digital signal of this second predetermined field begin to deposit in proper order from the original position of this field buffer.

6, double-image display device as claimed in claim 1, wherein said field buffer are a first-in first-out register.

7, a kind ofly be used for showing that one first vision signal and one second vision signal are in the double-image display device of the and arranged on left and right sides of a screen, this two vision signal all includes a strange scanning field and an even scanning field, when being shown in this screen simultaneously, this strange scanning field and even scanning field just can form a video pictures, this two scanning field all includes the horizontal time-base of a predetermined number, this display unit comprises: (1) first digital circuit comprises:

(a) a synchronous demultiplexer is used for separating the level and the vertical synchronizing signal of first vision signal;

(b) analog/digital converter is used for converting each horizontal time-base of first vision signal to digital signal, and

(c) line buffer is used for storing this digital signal; (2) second digital circuits comprise:

(a) a synchronous demultiplexer is used for separating the level and the vertical synchronizing signal of second vision signal;

(b) analog/digital converter is used for converting each horizontal time-base of second vision signal to a digital signal;

(c) field buffer comprises a plurality of memory locations, is used for successively from open the digital signal that all horizontal time-bases that the beginning position begins to store a scanning field of described second vision signal are produced after changing; (3) one control circuits are electrically connected on described first and second digital circuit, comprising:

Whether strange, the even scanning field that (a) synchronous detector, the synchronizing signal that is used for producing according to first and second digital circuit detect this first and second vision signal is homologous field and produces an output;

(b) a field buffer control device, be used for controlling the output of digital signal in the described field buffer, the digital signal that wherein is stored in first predetermined field of second vision signal in this field buffer is to begin output from the original position of this field buffer successively, and the digital signal of second predetermined field of described second vision signal then is to determine position that it is begun to export successively by this field buffer so that two scanning fields of this first and second vision signal are shown on this screen synchronously according to the output of this synchronizing indicator;

(c) signal combiner is used for taking out and is stored in the digital signal in the described line buffer and takes out a digital signal to form a synthetic digital signal by this field buffer under the control of this field buffer control device; (4) one digital/analog converters are electrically connected on described control circuit, are used for converting described synthetic digital signal to a synthetic horizontal time-base; And (5) one display control circuits, be electrically connected on described digital/analog converter, be used for described synthetic horizontal time-base is shown on the described screen, so that described first and second vision signal can be shown in the left and right sides of this screen successively.

8, double-image display device as claimed in claim 7 also comprises a display control switch, and this switch comprises an output, is electrically connected on described display control circuit; One first input end is electrically connected on described digital/analog converter, is used for receiving described synthetic horizontal time-base; And one second input, be used for receiving described first vision signal, described switch is used to select to connect a end in this two input as the input of this display control circuit, makes this double-image display device show that successively this first and second vision signal is in the left and right sides of described screen or show that separately this first vision signal is on this screen thus.

9, double-image display device as claimed in claim 7, wherein said first predetermined field is a strange scanning field and described second predetermined field is an even scanning field, when digital signal that should the idol scanning field by from described field buffer output the time, if it is different that the output of described synchronizing indicator shows described first and second vision signal, then this field buffer control device is controlled the output of this field buffer so that the output of digital signal that should the idol scanning field is delayed the time of a digital signal.

10, double-image display device as claimed in claim 7, wherein said first predetermined field is an even scanning field and described second predetermined field is a strange scanning field, when the digital signal of this strange scanning field by from this field buffer output the time, if it is different that the output of described synchronizing indicator shows described first and second vision signal, then this field buffer control device control this field buffer output so that digital signal on the next position of this field buffer original position and subsequent digital signal begin to be exported successively.

11, double-image display device as claimed in claim 7, wherein when described field buffer is exported the digital signal of described second predetermined field, if the output of this synchronizing indicator shows that described first and second vision signal is a homologous field, then this field buffer control device control this field buffer output so that the digital signal of this second predetermined field begin to export successively from the original position of this field buffer.

12, double-image display device as claimed in claim 7, wherein said field buffer are a first-in first-out register.

13, a kind ofly be used for showing that one first vision signal and one second vision signal are in two picture display process of the and arranged on left and right sides of a screen, wherein this two vision signal all includes a strange scanning field and an even scanning field, when being shown in this screen simultaneously, this strange scanning field and even scanning field just form a video pictures, this two scanning field all includes the horizontal time-base of a predetermined number, and this method may further comprise the steps:

(1) isolates the synchronizing signal of first vision signal;

(2) isolate the synchronizing signal of second vision signal;

(3) by first and second vision signal isolated synchronizing signal judge whether the scanning field of this first and second vision signal is homologous field and produces an output;

(4) each horizontal time-base of first vision signal is converted to a digital signal and this digital signal is stored in the line buffer;

(5) each horizontal time-base with each scanning field of second vision signal converts a digital signal to;

(6) digital signal of second predetermined field of this second vision signal original position by a field buffer is begun to deposit in successively, this field buffer comprises a plurality of memory locations, is used for storing the digital signal that all horizontal time-bases of a scanning field of this second vision signal are produced after changing;

(7) digital signal of second predetermined field of determining this second vision signal according to the output in described (3) step opens the beginning memory location in this field buffer, and it is opened by this memory location of beginning deposits in this field buffer successively so that this second vision signal and this first vision signal are shown on this screen synchronously;

(8) with an output of the digital signal in the digital signal in the described line buffer and this field buffer and a synthetic successively combined digital signal, the digital signal in this field buffer is begun to export successively by its original position;

(9) this combined digital signal is converted to a combined horizontal sweep signal;

(10) this combined horizontal sweep signal is shown on this screen, so that this first and second vision signal is shown in the left and right sides of this screen successively.

14, method as claimed in claim 13, wherein said first predetermined field is a strange scanning field and this second predetermined field is an even scanning field, when digital signal that should the idol scanning field is stored in this field buffer, if the output in described (3) step shows that this first and second vision signal is a homologous field, digital signal that then should the idol scanning field begins to deposit in successively from the next position of this field buffer original position.

15, method as claimed in claim 13, wherein said first predetermined field is an even scanning field and this second predetermined field is a strange scanning field, when digital signal that will this strange scanning field is stored in this field buffer, if the output in described (3) step shows that this first and second vision signal is a homologous field, then the second digit signal of this strange scanning field and subsequent digital signal will begin from the original position of this field buffer to deposit in successively.

16, method as claimed in claim 13, wherein when the digital signal with this second predetermined field is stored in this field buffer, if it is different that the output in described (3) step shows this first and second vision signal, then the digital signal of this second predetermined field will begin from the original position of this field buffer to deposit in successively.

17, a kind ofly be used for showing that one first vision signal and one second vision signal are in two picture display process of the and arranged on left and right sides of a screen, wherein said two vision signals all include a strange scanning field and an even scanning field, when being shown in this screen simultaneously, this strange scanning field and even scanning field just can form a video pictures, this two scanning field all includes the horizontal time-base of a predetermined number, and this method may further comprise the steps:

(1) isolates the synchronizing signal of first vision signal;

(2) isolate the synchronizing signal of second vision signal;

(3) by first and second vision signal isolated synchronizing signal judge whether the scanning field of this first and second vision signal is homologous field and produces an output;

(4) each horizontal time-base of first vision signal is converted to a digital signal and this digital signal is stored in the line buffer;

(5) each horizontal time-base with each scanning field of second vision signal converts a digital signal to;

(6) digital signal of second predetermined field of this second vision signal original position by a field buffer is begun to deposit in successively, this field buffer comprises a plurality of memory locations, is used for storing the digital signal that all horizontal time-bases of a scanning field of this second vision signal are produced after changing;

(7) will be stored in the digital signal of this line buffer and a digital signal of this field buffer and take out a synthetic successively combined digital signal; The digital signal of first predetermined field of this second vision signal is begun to be exported successively by the beginning position of opening in this field buffer; The digital signal of second predetermined field of this second vision signal is then determined position that it is begun to export successively by this field buffer so that two scanning fields of this first and second vision signal are shown on this screen synchronously according to the output in described (3) step;

(8) this combined digital signal is converted to a combined horizontal sweep signal;

(9) this combined horizontal sweep signal is shown on this screen, so that this first and second vision signal is shown in the left and right sides of this screen successively.

18, method as claimed in claim 17, wherein said first predetermined field is a strange scanning field and described second predetermined field is an even scanning field, in digital signal that should the idol scanning field during from this field buffer output, if it is different that the output in described (3) step shows this first and second vision signal, the output of digital signal that then should the idol scanning field will be delayed the time of a digital signal.

19, method as claimed in claim 17, wherein said first predetermined field is an even scanning field and described second predetermined field is a strange scanning field, in digital signal that will this strange scanning field during from described field buffer output, if it is different that the output in described (3) step shows this first and second vision signal, then the digital signal and subsequent the digital signal that are stored on the next position of this field buffer original position of this strange scanning field will begin to be exported successively.

20, method as claimed in claim 17, wherein when from this field buffer, taking out the digital signal of this second predetermined field, if the output in described (3) step shows that described first and second vision signal is a homologous field, then this second predetermined field is stored in digital signal in this field buffer and will be successively begins output from the original position of this field buffer.

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