JPS6276367A - Television scanning conversion system - Google Patents

Abstract

PURPOSE:To attain an interlaced scanning in a real time even on a moving picture by synchronizing in and executing the write of a picture data by a sequential scanning and the read by the interlaced scanning with a prescribed phase relation. CONSTITUTION:A video signal S1 scanned sequentially and photographed by a telecamera 1 is generated as a digital data D1 at a A/D converter 2, being stored at a frame memory 3. The data stored at the memory3 is interlace- scanned by an interlaces scanning control part 6 and is read as a data D2, and is converted to an analog signal at a D/A converter 4, being taken out as a video signal S2. At such a time, the operation of the camera 1 is controlled by a sequential scanning control part 5 and also, an address signal in the sequential scanning is being sent to the memory 3, and a conversion control part 7 can perform the locking of the write by the sequential scanning of the data D1 and the interlaces scanning against the memory 3 in keeping th prescribed phase relation.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a television scanning conversion method for outputting images obtained by a progressive scanning television camera to an interlaced scanning device, and particularly for moving images. The present invention also relates to a television scan conversion method that can be converted to an interlaced scan method in real time.

BACKGROUND OF THE INVENTION There are two well-known methods of scanning television using Rusk scan: progressive scanning and interlaced scanning. Among these, the interlaced scanning method is widely used because it can reduce flicker in images over the same transmission bandwidth compared to the progressive scanning method, and Japan's standard television system also uses this method. . However, the above-mentioned reduction in image flickering is a request from the image display side such as a TV monitor, and at the single-image input end, that is, the TV camera.
Regardless of this, it is desirable to use a scanning method that is optimal for the imaging conditions.

For example, in an X-ray imaging device, blanking is applied at the timing when it becomes a television camera, and during this period, X-rays are emitted to produce an image on the imaging tube surface of the television camera. 9 times,
A method is adopted in which the image is then read out by scanning. However, in this case, the diameter of the e-beam has a certain spread, so in interlaced scanning, when reading out the scanning line of the first field, the scanning line of the adjacent second field is read out. Part of the signal was read out. Therefore, a signal level difference occurs between the read signal of the first field and the read signal of the second field, and flicker may occur. To avoid this, please read the above e-bee 1.
1 diameter may be made smaller, but in this case, the signal current for reading the scanning line decreases and the S/N ratio deteriorates. For these reasons, it is appropriate for a television camera in an X-ray imaging apparatus to perform imaging using a progressive scanning method in which the level difference between readout signals of adjacent scanning lines is not noticeable.

However, since most display devices such as television monitors or devices such as video tape recorders (VTRs) are of the interlaced scanning type as mentioned above, images taken with progressive scanning type television cameras and There is a demand for converting the data into interlaced scanning format and outputting it. Therefore, as a conventional conversion method of this type, for example,
By the progressive scanning method, as mentioned in Publication No. 1.07389? :) Once the image data is stored in a storage device, it is read out using an interlaced scanning method and the image data is displayed on a television monitor or the like.

Problems to be Solved by the Invention However, in such a television scanning conversion method, ■ All image data of a frame is once stored in a storage device and then read from the storage device using an interlaced scanning method. , is effective for converting and reading a still image for one frame, but it has not been possible to convert and read image data of consecutive frames one after another in real time. That is, it has not been possible to convert moving images to the interlaced scanning method and read them out in real time. Therefore, an object of the present invention is to solve such problems.

Means for Solving the Problems The means of the present invention for solving the above problems is to A/D convert a video signal from a progressive scanning television camera, and convert the resulting image data into a progressive scanning controller. The image data stored in the storage device is read out according to the address signal controlled by the interlaced scanning controller, and the image data obtained is D/A converted and interlaced scanned. In the television scanning conversion method for obtaining a video signal according to the method, the writing of image data by progressive scanning and the reading of image data by interlacing scanning are controlled at a predetermined phase between the progressive scanning control section and the interlaced scanning control section. This is achieved by providing a synchronization means to execute the operations synchronously.

Embodiments Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

FIG. 1 is a block diagram showing an embodiment of a television scanning conversion method according to the present invention. This television scanning conversion system converts images obtained by a progressive scanning television camera into interlaced scanning and outputs them. ,
It consists of a D/A converter 4, a progressive scan control section 5, an interlaced scan control section 6, and a conversion control section 7. Above TV camera 1
The image capturing apparatus captures images in a sequential scanning manner and outputs a video signal S. The A/D converter 2 inputs the video signal S1 from the television camera 1, digitizes it, and outputs it as image data D using a progressive scanning method. The frame memory 3 is a storage device that stores the image data D1 from the A/D converter 2, and is configured so that image data can be written and read simultaneously. The D/A converter 4 is connected to the frame memory 3
The image data T]2 read out from the input terminal is input, converted into an analog signal, and outputted as a video signal S2. Further, the sequential scanning control section 5 controls the image data D□ outputted from the A/D converter 2 to be written into the frame memory 3 by a sequential scanning method, and sequentially scans the image data D□ with respect to the frame memory 3. a vertical synchronization signal S4 and a horizontal synchronization signal S5 for controlling the operation of the television camera 1, as well as transmitting an address signal S to the television camera 1;
It also sends out a blanking signal S6. Furthermore, the interlaced scanning control unit 6 controls the image data stored in the frame memory 3 to be read out as image data D2 by the interlaced scanning method, and the interlaced scanning address In addition to sending out the signal S7, it also sends out to the D/A converter 4 a vertical synchronization signal S, a horizontal synchronization signal S9, and a blanking signal S1o for controlling its operation.

Here, in the present invention, the sequential scanning control section 5 and
A conversion control section 7 is provided between the interlaced scanning control section 6 and the interlaced scanning control section 6 . This conversion control section 7 serves as a synchronization means for writing the image data D1 into the frame memory 3 by sequential scanning and reading out the image data D2 by interlaced scanning in a synchronized manner while maintaining a predetermined phase relationship. , an enable signal Sl+ is sent to the progressive scan control section 5 to control its operation, and an enable signal S1+ is sent to the interlaced scan control section 6 to control its operation.

Next, the overall operation of the television scanning conversion system configured as described above will be described. First, the television camera 1 receives a vertical synchronizing signal S4, a horizontal synchronizing signal S5, and a blanking signal SI sent from the sequential scanning control section 5.
, performs sequential scanning and outputs the video signal S1. This video signal S is input to the A/D converter 2 and digitized, and the image data D is processed using the progressive scanning method.
Output as □. Next, this image data D□.

The data is written into the frame memory 3 in accordance with the progressive scanning address signal S sent from the progressive scanning control section 5.

In parallel with this writing operation, image data D2 based on the interlaced scanning method is read out from the frame memory 3 in accordance with the interlaced scanning address signal S7 sent from the progressive scanning control section 6. Next, this image data D2 is D
A vertical synchronizing signal S8, a horizontal synchronizing signal Sg, and a blanking signal S are inputted to the /A converter 4 and converted into analog signals, and sent out from the interlaced scanning control section 6. The video signal S2 is output to a television monitor (not shown) or the like as a video signal S2. Here, the progressive scanning control section 5 and the interlaced scanning control section 6 operate only while the enable signal S and the enable signal Stz are outputted from the conversion control section 7, respectively, and the above-mentioned signals S1□, S □
The operation is stopped while 2 is not output. Then, at the start of operation, the conversion control section 7 outputs an enable signal S to the progressive scan control section 5 and an enable signal S to the interlaced scan control section 6 by a predetermined time delay, thereby performing the sequential scanning. The writing of the image data D into the frame memory 3 by the interlaced scanning and the reading of the image data D2 from the frame memory 3 by the interlaced scanning are controlled so that they are synchronized while maintaining a predetermined phase difference. At this time, if the total number of scanning lines and frame rate of the writing by the sequential scanning and the reading by the interlaced scanning are equal, the synchronization with the above-mentioned phase difference will be maintained. Therefore, the conversion control section 7 may continue to send the enable signal S1□ and the enable signal S42 having the above phase difference to the sequential scanning control section 5 and the interlaced scanning control section 6, respectively.

Next, the phase difference between writing by the sequential scanning and reading by the interlaced scanning will be explained with reference to FIG.

FIG. 2 shows the state of writing and reading in the frame memory 3 in units of scanning lines, and (a) and (b)
), (c), and (d) in the order of one horizontal scanning period. At this time, writing of image data D8 by sequential scanning is performed at 1 and 2 in FIG.
゜3.4. The reading of the image data D2 by interlaced scanning is performed in the order of scanning lines 1, 3, 5, . . . in FIG. . . . is performed in the order of the scanning lines.

Assume now that reading by interlaced scanning proceeds with a phase difference that is delayed by one scanning line with respect to writing by sequential scanning. First, in Figure (a), the first scanning line is scanned as shown in a-) 1).

At this time, reading is not performed yet. Next, in Figure (b), writing of image data is performed on the second scanning line as shown in C-+d by sequential scanning.

During this time, one image data is read out as shown in (a-+l) with respect to the first scanning line written in the figure (a). That is, in this case, image data is read and written in parallel for the same frame. Next, in figure (c), image data is written to e-+ on the third scanning line by sequential scanning.
It is done like f. At this time, image data reading 7 is performed using interlaced scanning for the third scanning line.
−> f. That is, at this timing, reading catches up with writing of image data to the third scanning line, and both operations are performed simultaneously. In this case as well, image data reading and writing are performed in parallel for the same frame. Next, in figure (d),
Writing of image data is performed on the fourth scanning line from g to h by sequential scanning. At this time, image data is read out in the order of 1→J for the fifth scanning line by interlaced scanning. In other words, at this timing, the image data readout overtakes the write operation.

Therefore, the image data of the fifth scanning line that is being read this time is the image data that was highlighted in the previous frame. From this, after the timing shown in FIG. 3(d), image data is read and written between two consecutive frames. Therefore, with the phase difference delayed by one scanning line as described above, one frame of image after converting from progressive scanning to interlaced scanning will contain images of two successive frames. , it turns out that correct conversion is not possible.

Next, Figure 3 shows the phase difference and operation to prevent the above-mentioned mixing of two frames and to correctly convert one frame of writing using the progressive scanning method to reading within the same frame using the interlaced scanning method. Refer to and explain.

In FIG. 3, the total number of scanning lines Nt is 525,
"1, 2, 3 degrees...525 ++ is the scanning line number and indicates the scanning order by the sequential scanning method. Also, II l.

2.3. ...525'' indicates the scanning order by the interlaced scanning method. Each of the above scanning lines is read and written from left to right in Fig. 3 in units of one pixel or in units of several pixels. Code a r C+ e +g* J
-... represents the first pixel of each scanning line, b,
d, f, h, . . . represent the last pixel of each scanning line.

Now, a case will be described in which the number Nd of display scanning lines that actually illuminates the screen of a television monitor or the like is 480. , in this case, writing data by sequential scanning is Nd/2=24
If the phase difference is such that when pixel j of the 0th scanning line (240) (7) is reached, data reading by interlaced scanning starts from pixel a of the 1st scanning line, then writing by sequential scanning is In FIG. 3, "240, 241.
The reading by interlaced scanning is performed in the order of the scan lines ul, 2...''.

Therefore, as shown in FIG. 2(C), the reading of image data catches up with the writing of image data only after the fourth
This is the first pixel g of the 79th scanning line (479), and data is written and read simultaneously in each pixel of this 479th scanning line. At this time, as is clear from FIG. 3, the scanning line by interlaced scanning is in the 240th order, and this is the last display scanning line of the first field read by interlaced scanning. Therefore, each pixel of the first field by interlaced scanning that has just been read out is
These are all pixels in the same frame written this time by sequential scanning. Next, reading out the second field by interlaced scanning returns to the 264th scanning order, that is, the second scanning line (2), and starts reading data from the first pixel C of this scanning line. At this time, 17 scans of the next frame by sequential scanning are performed on the first scanning line (1
) and starts writing data from the first pixel a of this scanning line. That is, the reading of the second field by the interlaced scanning precedes the writing of the next frame by the sequential scanning.

Therefore, each pixel in the second field read out by interlaced scanning as described above is also a pixel in the same frame written this time by sequential scanning. By maintaining such a phase relationship between writing and reading, one frame of writing using the progressive scanning method can be correctly converted into reading within the same frame using the interlaced scanning method.

However, if the start of reading by interlaced scanning is earlier than the above timing, data reading will catch up with writing before pixel q, and the last part of the first field of reading by interlaced scanning will be the same as the previous frame. The image data will be written in , and the correct conversion will not be performed.

Next, a case where the number of display scanning lines Nd is 481 will be explained. In this case, data writing by sequential scanning is N
d/2 241st (rounded up) scanning line (241
) when reaching pixel Q.

Assuming that the phase difference is such that data reading by interlaced scanning starts from pixel a of the first scanning line, the Nd
Proceeding in the same way as in the case of =480 lines, it is at the 481st scan, the first pixel S of m (481), that the reading of image data catches up with the writing of image data. At this time, as is clear from FIG. 3, the scanning line by interlaced scanning is the 241st scanning line, which is the last display scanning line of the first field read by interlacing scanning. Therefore, each pixel of the first field by interlaced scanning that has just been read is a pixel in the same frame that has been written this time by sequential scanning.

Thereafter, the second field is read out by interlaced scanning in the same manner as in the case of Nd=480 lines. By maintaining such a phase relationship between writing and reading, even when Nd = 481 lines, one frame of writing using the progressive scanning method can be correctly converted into reading within the same frame using the interlaced scanning method.

Next, a description will be given of the phase difference when the total number of scanning lines Nt is 525, regardless of the number Nd of scanning lines per display. In this case, when data writing by sequential scanning reaches the last pixel P of the 263rd (rounded up) scanning line ("101"), data reading by interlaced scanning is started. Assuming that the phase difference starts from the first pixel a of the scanning line of
In the figure, the scanning lines are read out in the order of "264, 265...", and the reading by interlaced scanning is i+1.2°.
...' are performed in the order of the scanning lines. Therefore, the reading of image data catches up with the writing of image data when the writing reaches the last pixel of the first scan line and the reading reaches the 264th scan order using interlaced scanning, that is, the second scan. This is when the first pixel C of line (7) is reached. In this case, as in the above two cases, the image data is read out by interlaced scanning for the first field after writing the image data by sequential scanning, and for the second field, the reading of the image data by interlaced scanning is performed after the writing of image data by sequential scanning for the second field. This will precede writing. Therefore, by maintaining such a phase relationship between writing and reading, it is possible to correctly convert one frame of writing using the progressive scanning method into reading within the same frame using the interlaced scanning method. However, if the start of reading by interlaced scanning is later than the above timing, data reading will catch up with writing after pixel C, and the first part of the second field read by interlaced scanning will be written as the next frame. image data, and correct conversion will not be performed.

From the above, writing of image data by sequential scanning is possible from the first pixel j of the 240th scanning line or the first pixel Q of the 241st scanning line in FIG.
The conversion control shown in FIG. 1 is performed so that reading of image data by interlaced scanning starts from the first pixel a of the first scanning line when the pixel is between the last pixel p of the 63rd scanning line. The sending timing of the enable signal S11 and the enable signal S12 from the unit 7 may be set. This allows a progressive scanning image to be converted into an interlaced scanning image and output in real time.

In the embodiment shown in FIG. 1, both the progressive scanning control section 5 and the interlaced scanning control section 6 are controlled by the enable signal S□1 and the enable signal S12 from the conversion control section 7, respectively. The present invention is not limited to this.
The other may be controlled based on the vertical and horizontal synchronization signals of either one of i5 and i6. In this case, it is only necessary to actively add control signals such as enable signals to either one, and only take out vertical and horizontal synchronization signals and address signals from the other, so the present invention can be applied to existing television systems. It is possible to reduce the number of man-hours and cost 1- when applying the method.

In addition, in Fig. 3, we have explained the case in which strictly correct conversion is performed for progressive scanning images, but for example, in actual images from an X-ray imaging device, useful information is concentrated in the center of the image, and the useful information is concentrated in the periphery of the image. contains almost no information, so the phase difference that synchronizes writing by progressive scanning and reading by interlaced scanning in this case is equal to the number of display scanning lines N.
There is no practical problem even if the phases are synchronized by a maximum of ±25% of d (=480.4.81). In this case, the conversion control section 7 as the synchronization means can be further simplified, and it is possible to reduce the size and cost.

Effects of the Invention As described above, the present invention provides an arrangement between the progressive scanning control section 5 and the interlaced scanning control section 6 to control the writing of image data by progressive scanning and the reading of image data by interlaced scanning at a predetermined phase. Since the conversion control unit 7 is provided as a synchronizing means to execute the conversion in synchronization, the image data D from the sequential scanning television camera 1 is written to the frame memory 3 by sequential scanning, and at the same time 3
The image data D2 can be converted into an interlaced scanning method and read out. Therefore, even continuous frames of image data can be converted and read out one after another in real time.
Video signal S2 using interlaced scanning method in real time
can be converted to . For this reason, in moving image input devices such as television cameras, the progressive scanning method can be used as the optimal scanning method depending on the shooting conditions, and the interlaced scanning method with less flicker can be used as a display device. I can do it.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing an embodiment of the television scanning conversion method according to the present invention, and FIG. 2 is an explanatory diagram showing the phase difference between writing by progressive scanning and reading by interlaced scanning.
FIG. 3 is an explanatory diagram showing the phase difference and operation for correctly converting one frame of JF input using the progressive scanning method into reading within the same frame using the interlaced scanning method. 1. TV camera 2.・Δ/D converter 3 Frame memory (storage device) 4-D/A converter 5 ・Sequential scanning control unit (--Interlaced scanning control unit 7 ・Conversion control unit (1tJI means), S, ・Sequential scanning system Video signal S2 by interlaced scanning method Video signal S by interlaced scanning method... Address signal S7 of sequential scanning... Address signal S of interlaced scanning, 1.S□2... Enable signal Di, D2... image data

Claims (1)

[Claims] A/D converts video signals from progressive scanning television cameras
The image data thus obtained is written into a storage device according to an address signal controlled by a sequential scanning control section, and the image data stored in this storage device is read out according to an address signal controlled by an interlaced scanning control section. In a television scanning conversion method in which the obtained image data is D/A converted to obtain a video signal based on an interlaced scanning method, a method for converting image data using a progressive scanning method is provided between the progressive scanning control section and the interlaced scanning control section. 1. A television scanning conversion method, characterized in that a synchronizing means is provided for synchronizing and executing writing and reading of image data by interlaced scanning in a predetermined phase relationship.