JPS581779B2 - Beam regulation mark position detection method in character signal generator - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a character signal generator that outputs a desired character signal by scanning a character pattern with a beam of light or electrons;
In particular, character signal generation enables accurate scanning of a desired character pattern by correcting the beam position using a signal obtained by scanning in advance beam regulation marks applied to each character pattern. The present invention relates to a method for detecting the position of the beam defining mask in a device.

As a character signal generator, it scans a character pattern with a beam of light or electrons and outputs a desired character signal.
For example, those using a monoscope tube, those using an image pickup tube that accumulates character images projected from an optical dial, or those that scan an optical dial with a light beam generated by a flying spot tube. Various methods are known, such as those that have been used, but in any of these cases, accurately positioning the beam at a predetermined position is a prerequisite for obtaining high-quality character signals, and one of the means for achieving this is For example, a beam regulation mark (hereinafter simply referred to as a mark) is applied to each character pattern, and the beam deflection signal is corrected using the position signal obtained by detecting the mark in advance, and the desired character pattern is A method is known in which the image is scanned.

However, this method is susceptible to part of the mark being missing, especially the mark image being missing due to dust or scratches.
Therefore, there is a drawback that the above-mentioned position signal for correction cannot always be obtained accurately.

The present invention has been made in view of the above points, and specifically, the rectangular mark having one side in the same direction as the beam scanning direction (X direction) is placed in a predetermined manner corresponding to each character. It corresponds to the position of the virtual reference line set on the mark by digitally detecting the maximum values of the X-direction component and the Y-direction component of the distance from the arbitrary origin to the end of the mark. The present invention provides a mark position detection method that obtains a signal obtained by detecting a mark.

The following explanation will be based on an example in which an image pickup tube is used to accumulate character images projected from an optical dial.
The present invention is not necessarily limited to this, but can of course be applied to character signal generators of the various types described above in which beam position defining marks are provided for each character pattern.

FIG. 1 is an explanatory diagram showing the general positional relationship of character patterns and regulation marks accumulated on the tube surface of an image pickup tube, where 1 is a character area corresponding to one arbitrary character, and 2 is an explanatory diagram for the character area. Beam definition marks 3 and 4 placed at predetermined positions are virtual reference lines that are not actually made, and point P is the origin for explaining the positional relationship below, and is the origin in the x and y directions. X on each image pickup tube deflection system.

and y. This is the point at which the readout beam lands when a deflection signal of .

By the way, x1(t) and y1(t
) is a well-known raster scanning deflection signal as shown in Fig. 2, point Q can be set by applying deflection signals X and Y expressed by equation (2) as shown in Fig. 1 to the deflection system. Although it is possible to accurately raster scan the character area 1 as a starting point, the present invention always uses the formula This allows the values of xd and yd to be detected accurately.

FIG. 3 is a diagram illustrating the scanning state of the mark 2 which is carried out in advance before scanning the character area 1 in order to detect the xd and yd, and FIG. 4 is a circuit for realizing the present invention. FIG. 5 is an explanatory diagram showing the waveform of each signal in FIG. 4.

As shown in FIG. 3, the scanning area 5 for the mark 2 is set to be somewhat larger than the mark 2 itself, but this is due to the error when the mark 2 and the character pattern 1 are projected and stored on the image pickup tube, and the image pickup tube. The mark 2 is designed so that the mark 2 can be scanned at all times by taking into consideration the error between the deflection signal applied to the position and the actual landing position of the readout beam.

Next, based on FIGS. 3, 4, and 5, it will be explained,
When the raster scanning start signal 6 for the scanning area 5 is issued, deflection signals x2(t) and y2(t) as shown in FIG. 5 are sent from an external circuit (not shown) to the input terminals 7 and 8.
is input to adder circuits 9 and 10 via CP
Signals x0 and y0 for deflecting the beam to point P are supplied from U11, and the sum of these two signals, i.e., X=x
The signals 0+x2(t) and Y=yo+y2(t) are output to the deflection circuit of the image pickup tube, so that the image pickup tube scans the scanning area 5.

At this time, in FIG. 4, a flip-flop (hereinafter simply referred to as FF) 13 is set by a start signal 12 issued at each start of each scanning line, and as a result, an AND circuit 14 is set.
The clock signal 16 is input to the X counter 17 via the OR circuit 15 and counted.

The counted value is sent as an A signal to the size discrimination circuit 18 and also to the AND circuit group 19. For example, as shown in the scanning line 20-1 shown in FIG. If it is not detected, as will be described later, the AND circuit 21 is non-conductive and no set signal is generated, so the contents of the X register 22 are not updated, and the start signal 12 is output when moving to the next scanning line. As a result, the X counter 17 is reset to zero, returns to its initial state, and waits for the next scan.

Next, when the mark 2 is detected during one scan as shown in the scanning line 20-2 shown in FIG.
and the clock signal 16 are output to the inverter 2.
4 to the FF 13 to reset the FF 13, thereby rendering the AND circuit 14 non-conductive and blocking the passage of the clock signal 16. At the same time, the AND circuit 25 and the OR circuit 15 are newly activated. The clock signal 16 is supplied to the X counter 17 via the X counter 17.

Therefore, the X counter 17 continues to count the clock signal 16.

When the video signal 23 is detected as described above, the F
Since F13 is reset, the video signal 23 ends and the AND circuit 25 becomes non-conductive, and at the same time, the supply of the evening lock signal 16 to the X counter 17 is stopped.

Therefore, in the end, the X counter 17 has the scanning line 2 in FIG.
For 0-2, a count value corresponding to the length xd1 is held.

The value held in the X counter 17 is sent as the A signal to the magnitude discrimination circuit 18 and also to the AND circuit group 19 as described above.

The size discrimination circuit 18 detects the output signal of the X register 22 (
When the A signal is larger than the B signal), a signal is output, and the AND circuit group 19 is operated by the signal, and the value of the X counter 17 is supplied to the input terminal of the X register 22.

When the scan end signal 26 as shown in FIG. 4 is supplied while the signal is being output from the magnitude discrimination circuit 18, the signal is already supplied from the reset side terminal of the FF 13, so the AND circuit 21 becomes conductive and generates a set signal, and in response to the set signal, the contents of the X register 22 are updated to a value equal to the A signal.

Due to the operation of such a size discrimination circuit, the maximum value of the length xdl obtained in the past scan is stored in the X register 22.
Therefore, in the case of Figure 3, mark 2
Although there is a missing portion 27 in , the value held in the X register 22 is a value corresponding to the length xd of the X-direction component of the distance from the origin P to the virtual reference line 3.

Next, to explain the operation of the Y counter 28, when the raster scanning start signal 6 is supplied to the circuit shown in FIG.
As a result of setting F29, the scan end signal 26 is sent to the Y counter 28 via the AND circuit 30 and the OR circuit 31.
are input and counted.

Next, when the mark 2 is detected as shown in the scanning line 20-2 shown in FIG. It becomes non-conductive and blocks the passage of the scan end signal 26, and the FF 32 is set.

The FF 32 set in this way is reset by the reverse signal of the scan end signal 26 that appears next, so that in the end, a video signal is detected from the set side terminal of the FF 32 during the scan. One signal is obtained for each scanning line, and this signal is sent to the OR circuit 3.
1 to the Y-counter 28.

Therefore, the Y counter 28 continues to count +1 in response to the scan end signal 26 which is output one by one for each scan line.

As mentioned above, once the video signal 23 is detected, the FF 29 is reset, so the scanning line 20- shown in FIG.
3, when the video signal of mark 2 is no longer detected, the OR circuit 31 is no longer supplied with any signal, and as a result, the Y-column 28 receives the mark 2 from the first scanning line in the scanning area 5 of FIG. The number of scanning lines up to the last scanned line, that is, the value corresponding to the length yd of the y-direction component of the distance from the origin P to the virtual reference line 4 is held.

Next, when the scanning for the scanning area 5 is completed, the
The CPU 11 reads the values held in the register 22 and the Y counter 28, and based on the read values, the CPU 11 calculates x0+xd+ΔX and y0+ in FIG.
The deflection signal corresponding to yd+△y is sent to the register 33 in FIG.
and output to 34.

By the way, as mentioned above, the value held in the X register 22 corresponds to the maximum value of the length xd1 in each scanning line, that is, the distance xd from the origin P to the virtual reference line 3, and
Since the value held in the counter 28 is the length yd, that is, the distance from the origin P to the virtual reference line 4, as shown in FIG. 27, the register 3
3 and 34 always include the aforementioned x0+xd+△X and y
Deflection signal corresponding to o + yd + △y, i.e. point Q in Fig. 1
This will provide a signal to deflect the beam.

Therefore, in the next character area scanning mode, if raster scanning deflection signals x1(t) and y1(t) corresponding to character area 1 in FIG. As a result, the deflection signals X and Y expressed by the above formula (2) are obtained, and by applying these signals to the deflection system of the image pickup tube, it becomes possible to accurately raster scan the character area 1 from the point Q. .

As described above in detail based on actual circuit examples, the present invention corrects the beam position by scanning the beam regulation marks made in correspondence with each character pattern in advance and using the signals obtained. In a character signal generator configured to scan a desired character pattern, the beam defining mark is rectangular and one side thereof is in the scanning direction of the beam (
The maximum value of the X-direction component and the Y-direction component of the distance from the arbitrary origin to the end of the mark is digitally detected and corresponds to the position of the mark. The present invention provides a mark position detection method characterized by a signal that is set to the beam definition mark, so that even if the beam definition mark has a missing part due to dust or scratches, the mark is always set to the mark. This has the effect that the position of the virtual reference line can be detected accurately, and as a result, a desired character pattern can be accurately scanned and a high quality character signal can be obtained.

Note that the scanning area for mark 2 in the present invention does not necessarily have to be set somewhat larger than mark 2 as shown in FIG. 3; for example, as shown in FIG. Of course, the scanning area 5 may be located inside the area 2.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram showing the general positional relationship between the character area 1 and the beam defining mark 2, FIG. 2 is a diagram showing a deflection signal for raster scanning the character area 1 in FIG. 1, and FIG. FIG. 4 is a diagram illustrating an example of a circuit for realizing the present invention. FIG. 5 is an explanatory diagram showing the waveform of each signal in FIG. 4. FIG. 4 is a diagram showing another embodiment different from FIG. 3 of the scanning area 5 for the regulation mark 2. FIG. 1... Character area, 2... Beam definition mark, 34... Virtual reference line, 5... Scanning area, 6... Raster scanning start signal, 12... Scanning start signal, 16... Clock signal, 17... X counter...large/small discrimination circuit, 20-1~2
0-3...Scanning line, 22...X register, 23...Video signal, 26...Scan end signal, 27...Missing portion, 28...
...Y counter.

Claims (1)

[Claims] 1. In a character signal generator that scans a character pattern by correcting the beam position using a signal obtained by pre-scanning a beam definition mark applied to each character pattern, the beam definition mark is It is made into a rectangular shape so that the direction of one side is in the same direction as the beam scanning direction (X direction), and the maximum value of the X direction component and the y direction component of the distance from the arbitrary origin to the end of the mark is digitally calculated. A method for detecting the position of a beam defining mark, characterized in that the position of the beam defining mark is detected and used as a signal corresponding to the position of the mark.