JPH065275B2 - Video display - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a video display device for displaying a signal obtained from a device for displaying polar coordinates such as PPI scan of radar by raster scan.

[Conventional technology]

In general, a radar image display is performed by a PPI scan for displaying an image on a display surface 2 formed by rotating a sweep line 1 extending from the center in the circumferential direction in synchronization with the rotation of an antenna as shown in FIG. It is being appreciated.

However, this method requires a cathode ray tube with afterglow and has a drawback that the screen must be viewed through the hood because of its low brightness, so in recent years, the signals obtained by PPI scanning are rasterized. There is a proposal to convert and display the scan.

In case of PPI scan, points 11 to 1n on sweep line 1
Is the angle θ that changes clockwise from the reference point 3 in FIG.
Then, the coordinates of the points 11 to 1n can be represented by the distance from the center. On the other hand, in the case of raster scanning, the points 11a to 1na on the scanning line 4 indicate the center of the circle and the display starting point 5
Then, the coordinates can be represented by the vertical position and the horizontal position from the display start point 5.

From this, in order to convert the position information of the points 11 to 1n in the PPI scan into the position information of the points 11a to 1na in the raster scan, a minute position change in the vertical direction in the raster scan based on the value of the angle θ in the PPI scan. The amount Δcos θ and the minute positional change amount Δsin θ in the horizontal direction are obtained, and by accumulating these values, points 11a to 1n corresponding to points 11 to 1n on the virtual line 1a corresponding to the sweep line 1
All you have to do is determine the coordinates of a.

In this way, the coordinates of the points 11a to 1na in the raster scan are determined, and the values are stored in the memory together with the luminance data at that point. The brightness data at this time is point 1a-
Intensity data of 1n is used. And sweep line 1
When the data is stored in the memory in accordance with the movement of, and the data is read and displayed in the scanning order, the signal of the PPI scan is converted into the raster scan and displayed.

In this case, in order to display the range mark, which is a distance marker, as a smooth line, it is conceivable to separately provide an auxiliary display point in the preceding direction on the PPI sweep of the display point and perform smoothing to control the luminance balance of both display points. To be

[Problems to be solved by the invention]

However, according to such a conventional method, as shown in FIG. 18, when a video display having an area such as an echo display of a radar is used, smoothing processing is performed in display point units even if the contour of the video has the same brightness. Since the brightness is modulated by the method described above, the brightness given to each display point is different when the brightness is modulated, and there is a drawback that uneven brightness occurs.

[Means for solving problems]

In order to solve such a drawback, according to the present invention, a coordinate conversion unit that sequentially converts points on a PPI sweep line into points on a raster scanning line at a predetermined processing timing, and a coordinate conversion unit sequentially converts the points on a raster scanning line. The three consecutive points in order from the newest are the next adjacent preceding point, the adjacent preceding point, and the current display point, of which the vertical and horizontal directions are divided by the intervals of the raster scanning lines and are points on the PPI sweep line corresponding to the current display point. A group selection unit that sets a point located at one of the corners of a square area that includes points as a group of light emission points for the converted point, and each light emission point set by the group selection unit as the distance from the converted point. The brightness setting unit that sets the brightness to an inversely proportional brightness, the first delay circuit that delays the brightness output of the light emitting point corresponding to the adjacent preceding point of the brightness setting unit by one processing timing, and the brightness setting unit A second delay circuit that delays the luminance output of the light emitting point corresponding to the adjacent preceding point by two processing timings, the luminance output of the light emitting point corresponding to the current display point of the luminance setting unit, the output of the first delay circuit, The data conversion unit that selects the maximum output of the two delay circuits and the output point from the data conversion unit that is displayed on the same raster are detected to have different intensities, and are output from the data conversion unit. Display start point determining unit that determines the display start point of the signal to be output, and a display end point that determines the display end point of the signal output from the data conversion unit based on the signals set as a group of light emission points determined by the group selection unit The signal output from the data conversion unit is selected for the range determined by the determination unit, the display start determination unit, and the display end point determination unit, and the signals other than that selected by the raster scan are selected and transmitted. It is obtained by a selector to be.

[Action]

In the process of coordinate conversion of the display point on the sweep scan line of the polar coordinate display system from the polar coordinate display system to the raster scan display system, the display point on the raster scan line and the display point on the raster scan line adjacent to the sweep scan line direction are The luminance data is correlated, and the smoothing process is turned on / off by detecting the contour portion of the video in sweep units as shown in FIG.

As a result, smoothing is performed only for the period required to display the range mark.

〔Example〕

FIG. 1 is a block diagram showing a video display device to which the present invention is applied, in which 10 is a coordinate detection unit, 20 is a modulation degree setting unit,
30 is a data conversion unit, 40 is a smoothing control unit according to the present invention, 50 is a group selection unit, 51 is a clock control unit, 52 is a brightness setting unit, 53 is a selector, 54 to 56 are shift registers, and 60 is a scan converter. is there.

If the current display point on the raster scan line that is currently displayed on the raster is the m-th point from the display start point 5, the coordinate detection unit 10 precedes this current display point m in the preceding display direction (display start point 5 The coordinates of the adjacent preceding point (m + 1) adjacent to the raster scanning line in the direction away from () and the coordinates of the next adjacent preceding point (m + 2) adjacent to the adjacent preceding scanning point (m + 1) on the raster scanning line in the preceding display direction. It is designed to calculate.

As shown in FIG. 2, the coordinate detecting unit 10 has a register 1
1, 13 and adders 12, 14. Second
The figure shows a portion for accumulating Δsin θ, and although not shown, there is a portion for accumulating Δcos θ with the same configuration as in FIG.

The modulation degree setting unit 20, as shown in FIG.
24 for transmitting the brightness-modulated signals of the current display point m, the adjacent preceding point (m + 1), and the next adjacent preceding point (m + 2) based on the signals supplied from the coordinate detecting section 10 and the group selecting section 50. It has become.

The positional relationship among the three points on the raster scanning line, that is, the current display point m, the adjacent preceding point (m + 1), and the next adjacent preceding point (m + 2) is one of the states shown in FIGS. 4 (a) to (e). Has been decided to be. FIGS. 4A to 4E are examples including a case where two of the three display points are at the same place and the two points are apparently displayed.

In FIG. 4, each display point is on the raster scanning line,
The side distance is a value corresponding to the interval between adjacent raster scanning lines, and the range surrounded by the four sides is defined as a pixel.

Since this pixel represents a range surrounded by four adjacent display points as shown in FIG. 12, it has the same size as the light emitting point (so-called pixel) on the scanning line of the display.

At this time, the relationship between the distance between adjacent coordinate-converted dots on the PPI scanning line (sweep) and the distance between the adjacent light emitting points on the raster scanning line is as follows.

The coordinate conversion of the sweep is as follows when the angle is θ as shown in FIG.

x _n = sin θ × m y _n = con θ × m Here, m is the number of cumulative additions, and the basic value of the cumulative additions is as follows.

x = 1 × sin θ y = 1 × cos θ Therefore, the interval between dots (calculated dots, that is, ideal coordinates) that is printed when m increases by 1 is always 1. FIG. 13 shows this state, and the black circles on the sweep are ideal coordinates.

By the way, since the maximum straight line length within one pixel of the area shown by the thick line portion in FIG. 14 is 2 ^1/2 , it is larger than the required length “1” of two dots and the required length “2” of three dots. Shorter than. This means that as shown in FIG. 14, the ideal coordinates indicated by black circles cannot be displayed during raster scanning, so the points indicated by circles are displayed, and as a result, two dots may be printed within one pixel. . Then, the display is performed on the adjacent display point for the first time at the third dot.

Of course, as shown in FIG. 15, the ideal coordinates and the points actually displayed may all be different.

Further, as shown in FIG. 16, the maximum straight line length in the four pixels in the area shown by the thick line portion is 2 × 2 ^1/2 , which is shorter than the required length “3” of four dots. This means that the fourth dot cannot be an adjacent display point to be modulated, as shown in FIG.

As described above, the display point can be set only on the scanning line. However, for example, if two points are emitting light and the brightness is the same and the distance between the two points is close, the light emitting point seems to be in the center between the two points and the brightness of the two points is different. For example, the light emitting point appears to be in the higher brightness.

In the case of FIG. 4 (c), when the display point "a" and the display point "d" have the same brightness, the apparent display point is in the center of the pixel, but the larger the brightness of the display point a, The apparent display point is close to the display point "a". The modulation degree setting unit 20 generates a signal for determining the brightness of the display point in this way, and sets the apparent display point at an arbitrary position in the pixel.

The data conversion unit 30 is composed of a ROM having a comparator function, and selects the maximum one of the three types of brightness data supplied to the input side.

As shown in FIG. 5, the smoothing control unit 40 includes a latch 41, a comparator 42, a shift register 43,
44, delay circuit 45, OR circuits 46, 47, 48, 4
9. When a graphic with a large area is displayed, the AND circuit 49a is configured to output a signal indicating whether or not the current display point is the outline of the graphic, and in response to the signal. The selector 53 selects and outputs the brightness-modulated data supplied from the data converter 30 and the data before brightness modulation supplied from the scan converter 60.

The group selection unit 50 is a ROM, and is adapted to generate a signal indicating which of the display states shown in FIGS. 4 (a) to 4 (e), each signal being defined as shown in Table 1. To be done.

At the same time, as shown in Table 2, a signal is generated which indicates which dot is shown in FIGS. 4 (a) to 4 (e).

The definitions of the main line dots and the complementary line dots will be described later.

The brightness setting unit 52 is a ROM, and the brightness data before brightness modulation transferred from the scan converter 60 is brightness-modulated by the data representing the modulation degree supplied from the modulation degree setting unit 20 and supplied from the scan converter 60. The brightness-modulated data is output as shown in FIG. 6 corresponding to the data representing the modulation degree. The luminance change in FIG. 6 is set so that the curve is smoothly displayed while considering the exponential change according to the visual characteristics.

The operation of the device configured as described above is as follows. First, the scan converter 60 sends accumulated basic value data for converting the polar coordinate data 5 to the rectangular coordinate data. This data is the horizontal minute distance data Δsin θ and the vertical minute distance data Δcos θ corresponding to the sweep angle θ in FIG. The coordinate detecting unit 10 has a second
There are two circuits shown in the figure, one of which is supplied with data of Δsinθ and the other of which is supplied with data of Δcosθ. However, since the type of data supplied is different, Timing pulse CK supplied
Both have the same circuit except that the timing of 1 is different.
Since the operations are the same, only the operation of the horizontal coordinate detecting portion shown in FIG. 2 will be described.

When the horizontal minute distance data Δsin θ is supplied from the scan converter 60 and the timing pulse CK1 is supplied from the clock control unit 57 to the coordinate detection unit 10, the register 11 shown in FIG. The captured data is held until the clock pulse CK1 is supplied.

The clock pulse CK1 is generated every one sweep, and therefore, the captured data is retained during the sweep from the center point to the outer peripheral end shown in FIG. 9, and the next sweep is performed. The data currently supplied to the register 11 at the time of start is newly taken into the register. Note that the vertical distance data Δ
cos θ is taken into the corresponding register by the timing pulse CK3 having a different timing from the timing pulse CK1.

When the horizontal direction minute distance data Δsin θ is taken into the register 11, the clock pulse CK2 which is the scan conversion clock of the scan converter is successively supplied, so that this data is supplied by the adders 12 and 14 and the register 13 to the clock pulse CK2. Is accumulated every time is supplied.

At this time, the output signal 100 of the register 13 indicates the ideal coordinates in the pixel of the dot at that time, and the output signal 104 of the adder 12 obtained by adding Δsin θ to the value is the dot displayed next, that is, the output. Assuming that the dot of the signal 100 is displayed m-th (hereinafter, this dot is referred to as dot m), the output signal 104 is (m + 1).
The position of the dot displayed next (hereinafter, this dot is referred to as dot (m + 1)) is indicated.

The carry signal 102 of the adder 12 indicates whether or not the dot (m + 1) has moved to another pixel, and the carry signal 101 of the adder 14 is the (m + 2) th dot [hereinafter,
This dot is called a dot (m + 2)] is a dot (m
+1) indicates whether the pixel has moved to another pixel.

There are 16 combinations of carry signals, which are shown in FIG. However, as described above in the operation during coordinate conversion of the PPI sweep, the state without carry of three consecutive dots is that the required length “2” for three dots on the PPI sweep is the maximum straight line in the pixel. Since the length is larger than 2 ^1/2 , there is no actual operation in the pattern. Therefore, there are 15 combinations in this case.

Then, the coordinate detection unit 10 outputs a signal indicating the positional relationship between the dot (m + 1) and the dot (m + 2) with respect to the dot m during transfer of the dot m, and ideal coordinates, that is, the position of the dot to be displayed.

Of the signals output from the coordinate detection unit 10, the output signal 1
00 is supplied to the modulation degree setting unit 20, and the carry signal 10
1, 102 are supplied to the group selection unit 50. Since the coordinate detection unit 10 has two systems of circuits as described above, the modulation degree setting unit 20 is supplied with two types of signals and the group selection unit 50 is supplied with four types of signals.

Based on the supplied four types of carry signals, the group selection unit 50 indicates which of the display positions of the dots m, (m + 1), (m + 2) is (a) to (e) in FIG. Or first
The signals shown in the table are output, and the constituent dots at this time are output by the signals shown in Table 2.

Table 2 shows the main line dots m and the supplementary line dots (m + 1), (m +
In the state of 2), the main line dot m is the above-mentioned m-th dot, and since the brightness data is supplied from the scan converter 60 to this dot, when expressing the constituent dots, the dot m Is expressed as a main line dot m.

Further, the complementary line dots (m + 1) and (m + 2) are the (m + 1) th dot and the (m + 2) th dot described above, and this dot is actually obtained by the combined luminance of the main line dot and this dot. This is to determine where the observed position is within the pixel.

In this way, the dots (m + 1) and (m + 2) are auxiliary dots, and therefore, when expressing the constituent dots, these dots are expressed as complementary line dots. However, the auxiliary dots (m + 1) and (m + 2) may overlap, and the supplementary line dot (m + 1) may overlap the main line dot m.
Note that classification based on the data supplied from the scan converter 60 as shown in Tables 1 and 2 is defined as case classification.

The modulation degree setting unit 20 sets the dots m, (m +) according to the ideal coordinate data of the dot m supplied from the coordinate detection unit 10 and the divided data supplied from the group selection unit 50.
1), the modulation degree is set, which is what kind of difference is made in the brightness of (m + 2).

As shown in FIG. 11, the display pattern of FIG. 4 divides the inside of a pixel to set the modulation degree, and the modulation degree can be selected from 16 types from 0 to 15. Since the gradation of the scan converter is 16 gradations, this is adapted to the characteristic. The operation of this part is as follows.

One of the five display patterns shown in FIG. 11 is selected from the group selection unit 50, and the display points a, b,
It is designated which of the dots m, (m + 1), and (m + 2) the dots c and d correspond to.

At the same time, the coordinate detection unit 10 outputs a signal representing the position of the ideal coordinate within the pixel indicated by the black circle in FIG. The modulation degree setting unit 20 sets the modulation degree of the display point by an inversely proportional method using the ideal coordinates and the distances ra and rb to the actual display point based on the above information.

The setting at this time is such that the sum of the modulation degrees of the respective display points is 15, that is, the same as the brightness of the display point at the maximum brightness. As a result, the ideal coordinates, that is, the brightness of the apparent display point is always constant and displayed.

The modulation factor is stored in a P-ROM and divided into four groups as shown in FIG.
, Dot (m + 1), and dot (m + 2) output terminals are provided, and these are connected to each other by a bus. The coordinate data of the ideal coordinates is input to each group as a P-ROM address, and the display state and the constituent dot selection signal input by the group selection signal are input to the P-ROM output enable and address.

The group of ROMs 21 to 23 for two-point modulation is input with a display state selection signal, and ▲ ▼ as an output enable signal, to select a constituent dot. And (m + 2), and if "1", m and m + 1.

On the other hand, the three-point modulation as shown in FIGS. 11 (d) and 11 (e) is organized in one group in the ROM 24.

In this case, the constituent dot selection signal Table signal and display status selection signal at address The display state is shown in FIG. 11 (d), and if it is "1", the display state is shown in (e).

By the above operation, one state is selected, and the modulation degree of each dot m, (m + 1), (m + 2) is determined.

Since the modulation degree data sent from the modulation degree setting unit 20 is supplied to the brightness setting unit 52, the brightness setting unit 52 calculates the dots m, (m + 1), (m + 2) based on the brightness data supplied from the scan converter 60. ) Are set according to the characteristics shown in FIG.

Among these data, the data of the dot m is directly supplied to the data conversion unit 30, the data of the dot (m +) passes through the shift register 56, and the data of the dot (m + 2) passes through the shift registers 54 and 55. Data converter 3
Supplied to zero. Then, the data conversion unit 30 selects the data of the maximum brightness among the data of the dots m, (m + 1) a, and (m + 2) b supplied at the same time, and sends it to the selector 53.

Of the data selected at this time, dot (m + 1) a
Since the data of (1) passes through the shift register 56, the data of the processing is delayed from the data of the dot m by one processing. That is, when the dot (m-1) that is one process before the dot m is displayed, the data is determined by assuming the dot one dot ahead, that is, the dot m.

Therefore, both the data directly supplied to the data conversion unit 30 from the brightness setting unit 52 and the data supplied via the shift register 56 are data representing the brightness of the dot m. Similarly, the data supplied to the data conversion unit 30 via the shift registers 54 and 55 is the data determined by assuming the dot two processing ahead from that point when displaying the dot (m-2). Therefore, the data also represents the brightness of the dot m.

That is, when displaying the dot m in the modulation degree setting unit 20, the dot (m + 1) one dot ahead and the dot (m + 1) two dots ahead.
Three types of data of +2) are sent, but these dots (m + 1) are for one processing, and dots (m + 2)
Is delayed by the processing time of two processes. Therefore, the data conversion unit 30 is set at the timing of displaying the dot m.
Only the data of dot m is transmitted from the data.

As a result, the selector 53 is provided with two types of luminance data, the data that has passed through the data conversion unit 30 and the data that is sent from the scan converter 60. Then, one of these data is selected and transmitted by the signal supplied from the smoothing control unit 40.
It is displayed on a display unit (not shown). At this time, when the data from the data conversion unit 30 is selected, the display smoothing is performed.

In this way, by displaying the output from the data conversion unit 30, the contour portion can be displayed as a smooth line. However, performing smoothing is nothing but changing the brightness of each dot, so if such smoothing processing is performed on all data,
The unevenness occurs in a portion having an area, which makes it difficult to see.

Therefore, such inconvenience can be avoided by performing the smoothing only on the portion where the luminance changes and not performing the smoothing on the portion where the luminance does not change.
The smoothing control unit 40 shown in FIG. 5 performs such control.

Now, as shown in FIG. 7 (a), the screen displayed is composed of parts indicated by symbols a, b, and c, the brightness of each part is different, and the sweep is performed in the direction indicated by the arrow. An example of such a case will be described. When the data of the dot B is supplied to the terminal A of the comparator 42,
The terminal B of the comparator 42 is supplied with the data delayed by one clock by the latch 41, that is, the data of the dot A. If the comparator 42 generates an output of "1" level when the data content of the terminal A is different from the data content of the terminal B, the brightness of the dot A and the dot B is different in this case.
Generates a "1" level output signal. Since this data is taken in by the shift register 43 and sent out from the terminals Q _A and Q _B , the selector 5 is operated via the OR circuits 49 and 48.
3 is supplied to the terminal S.

The selector 53 outputs the signal of the terminal B of the selector 53 when the "1" level signal of the terminal S is supplied, and outputs "0".
If the signal of the terminal A of the selector 53 is output when the level signal is supplied, the data of the dot B is supplied from the data conversion unit 30 to the terminal B of the selector 53, and smoothing is performed. The output data is output. In this way, the smoothing processing timing is determined.

The smoothing period is determined as follows. Smoothing is performed by controlling the brightness of 2 dots or 3 dots as shown in FIG. Therefore, when performing smoothing, it is necessary to continuously perform smoothing for a maximum of 3 dots.

Since the initial stage of smoothing is determined as described above, the smoothing period can be fixed afterwards by determining the end period of smoothing. Although the period determined by the above operation is 2 dots, smoothing may be required for 3 dots as described above. At that time, the following is performed.

Since the signal corresponding to each dot for performing smoothing is generated from the group selection unit 50 as described above, the end of smoothing when 3 dots are required can be determined based on this signal.

The group selection unit 50 does not perform smoothing. Sending out. Both indicate that a smoothing period of 3 dots is required.

Therefore, when these signals are output via the OR circuit 46, this signal is generated for one dot at the smoothing start time. By taking this in the shift register 44 and outputting it from the second and third stages, it is possible to obtain a signal for outputting the smoothed data for the second and third dots.

Since this signal is supplied to the terminal S of the selector 53 via the OR circuits 47 and 48, the data output from the 3-dot period data conversion unit 30 is output from the selector 53. Therefore, the dots B indicated by black circles in FIG.
Smoothing is performed on C and D.

Since the input data of the comparator 42 is the same when the dot E is displayed, the comparator 42 does not generate an output signal. Therefore, the output signal from the group selection unit 50 is masked by the AND circuit 49a and is not transmitted. For this reason, the output signal of the OR circuit 48 is at the “0” level, and therefore the data output from the scan converter 60 that has not been subjected to the smoothing process is output. Therefore, an image having an area can be displayed with uniform brightness without causing uneven brightness.

In the case of FIG. 7A, since the dots A and B have different luminances, the comparator 42 continuously outputs two dots. Therefore, 1 of the shift register 43
A signal for 2 dots can be obtained from only the output signal of the stage.
However, as shown in FIG. 7 (b), when the brightness is different between the part (a) and the part (b), the boundary of the brightness is a line with no width. Only an output signal can be generated.
Therefore, the output signal of the OR circuit 49 is used. If 3 dots are required, the output signal of the shift register 44 is secured for 3 dots by using the OR circuit 48.

Note that an actual image often has a luminance change represented by a normal distribution as shown in FIG. The initial smoothing detection and smoothing processing method described so far is performed when the brightness difference D in FIG. 8 is not zero, that is, when there is a brightness difference like the dots in FIG. There are problems when trying to express intensity modulation.

In this case, if the threshold value of the brightness difference is a positive number n, smoothing is performed when D> n is satisfied, and the range of brightness modulation is also set according to the brightness levels of a and b in FIG. It is possible to make various brightness changes. In this case, the comparator 42 is a ROM that stores a preset value of n.
Should be replaced with

〔The invention's effect〕

As described above, according to the present invention, when the change in the brightness of the adjacent display points is equal to or more than the predetermined value, the smoothing is performed over the predetermined period. Therefore, the area in the contour line is uneven in the brightness due to the smoothing. Has the effect of preventing the occurrence of

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of the present invention, FIG. 2 is a block diagram of a coordinate detecting unit, FIG. 3 is a block diagram of a modulation degree setting unit, and FIG. 4 is a diagram showing a positional relationship of each dot. , Fifth
FIG. 6 is a block diagram of the smoothing control unit, FIG. 6 is a diagram showing modulation factor characteristics written in the luminance setting unit, FIG. 7 is a diagram showing boundaries where smoothing is performed, and FIG. 8 is a luminance characteristic having a normal distribution. FIG. 9, FIG. 9 is a diagram showing a screen displayed in polar coordinate display, FIG. 10 is a diagram showing a screen displayed in raster scan display, and FIG. 11 is a diagram for explaining a modulation degree setting method. , FIG. 12 is a diagram for explaining the pixel size, FIG. 13 is a diagram for explaining the ideal coordinates and their intervals, and FIGS. 14 to 16 are where the luminance data of the ideal coordinates are actually displayed. FIG. 17 is a diagram for explaining a state where a carry occurs, FIG. 18 is a diagram for explaining problems of the conventional device,
FIG. 19 is a diagram for explaining a state in which contour detection is performed. 1 ... sweep line, 3 ... reference point, 4 ... scanning line, 5 ...
... Display start point, 10 ... Coordinate detection unit, 20 ... Modulation degree setting unit, 30 ... Data conversion unit, 40 ... Smoothing control unit, 50 ... Group selection unit, 51 ... Clock control unit, 52 ... Luminance setting unit, 53 ... Selector, 54-56 ... Shift register.

Claims (1)

[Claims] 1. A video display device for converting a graphic in a PPI scan into a raster scan for display, and a coordinate conversion unit for sequentially converting points on a PPI sweep line into points on a raster scan line at a predetermined processing timing; The continuous three points sequentially converted on the raster scanning line by the conversion unit are sequentially arranged from the latest one to the next adjacent preceding point, the adjacent preceding point, and the current display point, of which the vertical and horizontal directions are divided at the intervals of the raster scanning line, and the current display is performed. PPI corresponding to a point
A group selection unit that sets a point located at one of the corners of a square area including a converted point that is a point on the sweep line as a group of light emitting points for the converted point, and each set by the group selection unit. A brightness setting unit that sets the light emitting point to a brightness that is inversely proportional to the distance from the converted point, and a first delay that delays the brightness output of the light emitting point corresponding to the adjacent preceding point of the brightness setting unit by one processing timing. A circuit, a second delay circuit that delays the luminance output of the light emitting point corresponding to the next adjacent preceding point of the luminance setting unit by two processing timings, and a light emitting point corresponding to the current display point of the luminance setting unit. A data conversion unit that selects the maximum of the luminance output, the output of the first delay circuit, and the output of the second delay circuit, and the display points that are adjacent to each other on the same raster among the outputs from the data conversion unit. The display start point determining unit that determines the display start point of the signal output from the data conversion unit by detecting that the luminance of the light is different, and the signal set as a group of the light emitting points determined by the group selection unit. A display end point determining unit that determines a display end point of the signal output from the data converting unit based on the display end determining unit and a range determined by the display end determining unit selects the signal output from the data converting unit. Then
A video display device, characterized in that the other part includes a selector for selecting and transmitting a signal converted into a raster scan.