JPS62122477A - Digital data conversion system - Google Patents

Abstract

PURPOSE:To eliminate the deterioration in reproduced picture quality even when a level fluctuation takes place and an error is caused by arranging data during a silent signal period or dummy data to the end of a tape concentratedly in a system where a picture signal is digitized, sent or recorded and reproduced. CONSTITUTION:After an X-ray transmitted through a human body is amplified by an image intensifier 3, the result is converted into an electric signal by a TV camera 4. After the said signal is converted into a digital signal by an analog/digital converter 9, the signal is inputted to a digital memory 10. Dummu data is arranged on a part placed at the end of a tape from the digital memory 10 and recorded on a digital VTR 11. The output of the digital VTR 11 is inputted to a reproduction digital memory 12 and after the digital data is converted to reproduce the original picture, then a digital/analog converter 13 restores the signal to an analog signal, which is outputted to a television monitor 14.

Description

[Detailed Description of the Invention] [Field of Application of the Invention] The present invention relates to digital data conversion, and in particular to digital VT that digitizes and records and reproduces television image signals.
The present invention relates to a method for efficiently recording and reproducing data such as medical image signals in an R apparatus.

[Background of the invention]

In recent years, with the spread of computers, medical image diagnostic apparatuses equipped with computers have come into use, and diagnostic image data has been increasingly digitized. (Television Society Technical Report TEBS86-5.

TPA62-5 rIntroduction of Technicare DR-960 digital radiography equipment” December 20, 1982
1)). Initially, CT (computer tomography), which handles still images, etc., were created, but recently, I)SA (digital subtraction angiography), which handles moving images, etc. have been created.

FIG. 1 shows the image input part of a conventional r) SA table device.
It enters the image intensifier 3. After this image is converted into an electrical signal by the television camera 4, it is subjected to various image processing and recorded on a digital VTR, magnetic disk, or the like. In this device, an image intensifier 3 is used, and the human-powered image of the television camera 4 is different from a normal television screen, as shown in FIG.

It is a circular image. Therefore, the effective image area (effective scanning area) is πA2 where the radius is A, which is about 80% of the total area (2A''), and the remaining nearly 20% is an area that has no information at all. Conventionally used In the case of the analog recording method that was previously used, image identification numbers (■, D), etc. were only added to this area, and it was not used effectively.The reason for this is that in the case of analog signals, the data time This is because recording and reproducing by changing the axis is difficult in terms of accuracy and the size of one circuit.

When television signals are digitized, the data rate is approximately 100 megabits per second, which is extremely high speed and large capacity. For this reason, at present, digital data is once converted back to an analog signal and then recorded on an analog VTR (video tape recorder) or VDS (video disc recorder). However, these devices have the problem of adding noise and deteriorating the image quality each time recording and playback is repeated.
The drawback is that it is not accurate enough to digitize recorded data and reprocess it.

For this reason, recently, digital V, which digitizes television signals and records and plays back this digital data as is, has been developed.
Development of "l'H" is underway.Digital VTR
In this system, a helical scan method using a rotary head is adopted, and image data is recorded on the tape in the format shown in FIG.

The rotary head starts contacting the magnetic tape 5 from a portion A of the track 6, moves on the tape in a direction B to perform recording or reproduction, and leaves the tape at a portion B. In a VTR, at the point where the head starts contacting point A, or the part where the head starts contacting the tape, the tape contact becomes unstable due to the imbalance of the head contact, making it impossible to write or read data correctly on the tape. There is a problem. Even in digital VTRs, many code errors occur at the point where the head starts hitting the head. In a digital VTR, synchronization patterns indicating data divisions and parity for detecting and correcting code errors occurring during the recording/reproducing process are added to the horizontal and vertical periods of the television signal. To correct the code errors that occur frequently at the edge of the tape as described above,
There is a problem in that a very large number of parities are required and the circuit scale becomes large.

[Purpose of the invention]

The purpose of the present invention is to solve a problem in which errors occur frequently at the tape edge in medical imaging equipment, particularly equipment that records image data with a circular field of view, such as when using an X-ray image intensifier and a television camera. However, the object of the present invention is to provide a digital data conversion method that can efficiently record and reproduce data.

[Summary of the invention]

[Above] In order to achieve the first objective, the present invention provides a system for digitizing and transmitting or recording and reproducing television image signals whose effective field of view and effective scanning area are different. Concentrate on the edge of the tape. As a result, even if a level fluctuation occurs and an error occurs, there is no deterioration in the reproduced image quality.

[Embodiments of the invention]

Hereinafter, one embodiment of the present invention will be described in detail with reference to the drawings. FIG. 4 is a block diagram of a digital data recording and reproducing system showing an embodiment of the present invention. In this system, a television signal is converted into digital data and recording and reproducing processing is performed. In Fig. 4, 3 is an image intensifier that converts manually generated X-rays into visible light (TV camera imaging signal), 4 is a TV camera connected to the image intensifier 3, and 9 is an analog signal (TV camera image signal). (No. 8)
an analog/digital converter for converting the data into digital data; 10 is a digital memory for recording the television signal digitally converted by the analog/digital converter 9;
]1 is a digital VTR that records digital data,
12 is a digital memory for reproducing data recorded on a digital VTR, and 13 is a digital/digital memory for converting digital data into an analog signal (original television signal).
The analog converter 14 is a television monitor that displays the reproduced television signal image.

The X-rays that have passed through the human body are amplified by an image intensifier 3 and then converted into an electrical signal by an RV camera 4. This signal is converted into a digital signal by an analog/digital converter 9.

The data is input to digital memory 10. In this digital memory 0, as will be described later, dummy data is placed at the end of the tape to create a digital VTRI.
Record it in I. The output of this digital V'rR11 is input to a digital memory 12 for reproduction, and after converting the digital data to reproduce the original image, it is converted back to an analog signal by a digital/analog converter 13. After that, it is output to the television monitor 14.

FIG. 5 is a detailed configuration diagram of the digital memory 10 of FIG. 4. Here, lot, 102 is field memory, 1
03 and 104 are switches for switching digital data. Switches 103 and 104 are switched to alternately use field memories 101 and 102 to perform continuous data conversion. During playback, the digital memory 12 is used to restore the original image that has undergone the reverse conversion.

FIG. 6 is a diagram schematically showing sample points of data. Here, H indicates an image area in the horizontal direction, ■ indicates an image area in the vertical direction, and the shaded area 15 indicates data in a no-signal period. 1 to 20 indicate part of the effective image data 16.

FIG. 7 shows the image data after data conversion.

The shaded area 17 indicates dummy data, and 1 to 20 indicate valid image data 18. Through this data conversion, dummy data is allocated during the first few H periods (20% of all data) when the head starts hitting, and valid data is placed in the part where the head hits normally, so the impact if a code error occurs. can be reduced. Field memory 101 that performs this conversion
An example of the circuit is shown in FIG. Memory 105 for recording image data, dummy data generator 106 for creating dummy data
and a switch 107 for switching between the output of the memory 105 and the output of the dummy data generator 106. Among the output data of the digital data changeover switch 103, only the data of the valid period is recorded in the memory 105. Next, at the time of reading, prior to reading from the memory 105, the dummy data generated by the dummy data generator 106 is read, and then the data from the memory 105 is read and converted into the data shown in FIG.

The reproduced waveform of the converted data by one head is shown in FIG. 9. The reproduced waveform is composed of a dummy data section 19 and effective image data 20. Even when the output fluctuates due to the influence of head equilibrium in this manner, since the effective image data 20 is placed after the dummy data section 19, deterioration of the reproduced image can be prevented.

In addition, in digital vT1 (in order to perform high-density recording, the image is often divided and recorded and played back by multiple heads, but in this case, the whole image is recorded at the part where the tape of each divided image data starts to contact). A similar effect can be obtained by dividing the approximately 20% non-signal portion into the number of heads and arranging them.

Further, the aspect ratio of a normal television image is 3:4. However, in a medical image system using an image intensifier, the field of view is circular and the aspect ratio is 1:1, so the effective field of view of the television image 1- is as shown in FIG. Consisting of valid data 21 and no-signal part 22, the valid part is about 60% of the whole, and it is possible to place 40% of the no-signal part at the point where the head starts hitting.
The influence on image quality due to output fluctuations at the tape end can be further reduced.

〔Effect of the invention〕

As explained above, according to the present invention, when recording and reproducing data such as medical image signals in a digital VTR that digitizes and records and reproduces television image signals,
Even if an error occurs due to a level fluctuation at the end of the tape where it starts contacting the head, the effective image area is not affected and the reproduced image quality can be prevented from deteriorating.

[Brief explanation of drawings]

Figure 1 is a schematic diagram of a conventional X-ray device and camera system.
Figure 2 is an explanatory diagram of the effective screen area on both sides of the television, Figure 3 is a diagram showing the format of data recorded on the tape,
FIG. 4 is a block diagram of a digital data recording and reproducing system showing an embodiment of the present invention, and FIG. 5 is a block diagram of the digital memory shown in FIG. 4. 6 is a diagram showing sample points on a television screen, FIG. 7 is a diagram showing sample points after converting FIG. 6 according to the embodiment, FIG. 8 is a diagram showing the configuration of the field memory in FIG. Figure 10 shows reproduction data converted according to the embodiment.
The figure shows the effective screen area of a television screen in a system using an image intensifier. ■...X, Z tube, 2...Human body, 3...Image intensifier, 4...TV camera, 5...Tape, 6...Track, 9...Analog/digital Converter, 10... Digital memory, 11... Digital VTR 112... Digital memory, 13.
...Digital/analog converter, 14...TV monitor, 15...No signal period, 16...Valid image data, 17...No signal period, 18...Valid image data, 19... - Dummy data, 20... Valid image data, 21... Valid image data, 22... No signal period. Agent Patent attorney Okikata Ogawa (Pa' Figure 1 Figure 2 Figure 4 Part 4! S part 612) Part 7

Claims (1)

[Claims] 1. In a system for digitizing image signals having different effective field of view and effective scanning area for television images and recording and reproducing them on a magnetic tape, the video signal period of the television image signal is
A digital data conversion method characterized by dividing into a valid data part consisting of a valid field of view and an invalid data part other than the valid field of view, and recording and reproducing these parts in a temporally separated manner. 2. A digital data conversion system according to claim 1, characterized in that the first signalless data section is arranged at the end of a magnetic tape for recording and reproduction. 3. The digital data conversion method according to claim 1, wherein the shape of the effective field of view is a circle included in a quadrangle or an ellipse.