JPS61195378A - Video display method - Google Patents

Abstract

PURPOSE:To display a video contour by smooth lines to obtain a picture easy to see by deciding the position of the display points of the raster scan system based on the position data of the polar coordinate system, thereby determining the brightness of the respective display points. CONSTITUTION:The data DELTAsintheta, DELTAcostheta are sent from a scan converter 60 to a coordinate detector 10 and fetched in accordance with timing pulses CK1, CK3 from a clock control part 10 so as to be accumulated by CK2. The ideal coordinate signal 100 of dots from the detector 10 are supplied to a modulating part 20 while carry-out signals 101, 102 are supplied to a group selecting part 50. The selecting part 50 sends display the position signals of main and sub line dots to the modulator 20 while the modulating part 20 sets the modulation degree to the dots (m)-(m+2). A brightness setting part 52 sets the respective brightness based on the brightness data from the scan converter 60. The maximum brightness data are sent to the selector 53 through a shift registers 54-56 at a data converting part 30 and to display said data.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to an image display method for displaying signals obtained from a polar coordinate display device such as a PPI scan of a radar by raster scanning.

[Conventional technology]

In general, radar images are displayed by PPI scanning, which displays images on a display surface 2 created by rotating a sweep line 1 extending from the center in the circumferential direction, as shown in FIG. 9, in synchronization with the rotation of the antenna. It is. However, this method requires a cathode ray tube with afterglow properties, and the brightness is low, so the screen must be viewed through a hood.In recent years, signals obtained by PPI scanning have been used. It has been proposed to convert the image into a raster scan and display it.

In the case of PPI scan, points 11 to 1n on sweep line 1
The coordinates can be expressed by the angle θ that changes clockwise from the reference point 3 in FIG. 9 and the distances from the center of the points 11 to 1n. On the other hand, in the case of raster scanning, if the center of the circle is set as the display starting point 5, the coordinates of the points 11B to InjL on the scanning line 4 can be expressed by the vertical and horizontal positions from the display starting point 5. Therefore, in order to convert the positional information of points 11 to 1n in PP Niscan to the positional information of points 111 to IHm in raster scan, minute positions in the vertical direction in raster scan are calculated based on the value of angle θ in PP Niscan. The amount of change Δhataθ and the amount of slight positional change in the horizontal direction Δ81n
By determining θ and accumulating this value, sweep line 1
Point 1 corresponding to points 11 to 1n on the virtual line 1a corresponding to
It is sufficient to determine the coordinates of 1JL to 1nJL.

In this way, the points 11a to 1n in the raster scan
The coordinates of a are determined and the values are stored in memory along with the brightness data at that point. The brightness data at this time is point 1
Luminance data of 1 to 1n is used. Then, when the data is stored in a memory following the movement of the sweep line 1, and the data is read out and displayed in the scanning order, the PP Niscan signal is converted to raster scan and displayed.

[Problems to be Solved by the Invention] However, since such conventional devices can only display positions on the scanning line, in order to display a range mark that is a distance 1111 marker, When a circle is displayed, the circle is displayed as a discontinuous line, making it difficult to see.

[Means for solving problems]

In order to solve such drawbacks, the present invention provides that when displaying a point newly obtained by scan conversion, the adjacent preceding point adjacent to the point to be displayed in the preceding display direction of PP Niscan and its Among the next adjacent preceding points that are further adjacent in the preceding display direction from the adjacent preceding point, display the preceding points that exist within a square assumed in the preceding display direction with the distance between the adjacent scanning lines as one side from the point to be displayed. This is to apply brightness modulation to the desired point.

[Effect]

The position of the point to be displayed in the raster scan method is determined based on the position data in the polar coordinate system, and the brightness of each display point is determined based on this.

〔Example〕

Figure 1 is a block diagram showing one embodiment of this invention.
10 is a coordinate detection section, 20 is a modulation degree setting section, 30 is a data conversion section, 40 is a smoothing control section, 50 is a group selection section, 51 is a clock control section, 52 is a brightness setting section, 53 is a selector, 54 to 56 is a shift register, and 60 is a scan inverter.

If the current second point to be displayed on the rask is the m-th point from the display starting point 5, the coordinate detection unit 10 detects the previous display direction (direction away from the display starting point 5) from the current display point m. ), and the coordinates of the next adjacent preceding point (m+2) further adjacent to the adjacent preceding point (m+1) in the preceding display direction are calculated. As shown in FIG. 2, this coordinate detection section 10 is composed of registers 11 and 13 and adders 12 and 14. Although not shown in Figure 2, there is a part that accumulates Δfield θ with the same configuration as Figure 2.

As shown in FIG.
Based on the signals supplied from the coordinate detection section 10 and the group selection section 50, the present display point m, the adjacent preceding point (m+1), and the secondary adjacent preceding point (m+2) are transmitted with a signal for brightness modulation. It looks like this. Current display point m,
The positional relationship between the adjacent preceding point (m+1) and the next adjacent preceding point (m+2) is determined to be in one of the states shown in FIGS. 4(a) to 4(e). Figure 4(a)-(C
) is an example that includes a case where two of the three display points are not at the same location and are displayed as two points in appearance.

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

As mentioned above, display points can only be set on scanning lines. However, for example, if two points emit light and the brightness is the same and the distance between the two points is close, the light emitting point will appear to be in the center between the two points, and the brightness of the two points will be If they are different, the light emitting point will appear to be on the higher luminance side. In the case of Figure 4(c), if the brightness of display point "A" and display point "2" are made the same, the apparent display point will be in the center of the pixel, but the brightness of display point "A" will be increased. The closer the apparent display point is to the display point "A", the closer it becomes to the display point "A". The modulation level setting section 20 thus generates a signal for determining the brightness of a display point, and is used to set an apparent display point at an arbitrary position within a pixel.

The data conversion unit 30 is a ROM having a comparator function.
The maximum brightness data is selected from among the three types of brightness data supplied to the input side.

As shown in FIG. Comparator 42. shift) register 43,
44. Delay circuit 45. OR circuit 46.47.48,49
, and an AND circuit 50, and when displaying a figure with a certain area, it outputs a signal indicating whether or not the current display point is at the edge of the figure.
Depending on 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 section 50 is stored in a ROM and is shown in FIG.
) to (e), each signal is defined as shown in Table 1.

Table 1 Simultaneously generates a signal indicating which dots 4N(a) to (e) are made up of as shown in Table 2Table 2For the definitions of main line dots and supplementary line dots, , will be described later.

The brightness setting section 52 is stored in a ROM and performs brightness modulation on the brightness data before brightness modulation transferred from the scan converter 60 using the data representing the modulation degree supplied from the modulation degree setting section 20. As shown in FIG. 6, brightness-modulated data is output corresponding to the supplied data representing the degree of modulation. Incidentally, the brightness changes in FIG. 6 are set so that the curves are displayed smoothly while considering exponential changes in accordance with the visual characteristics.

The operation of the device configured as described above is as follows. First, cumulative basic value data for converting polar coordinate data into orthogonal coordinate data is sent from the scan converter 60. This data is horizontal minute distance data sin θ corresponding to the sweep angle θ in FIG. 9, and vertical minute distance data 蕉θ.

Inside the coordinate detection unit 10, there are two circuits shown in FIG. Since both have the same circuit and the same operation except for the difference in the type of data being processed and the difference in the timing of the timing pulse CKI supplied to the register 11, the horizontal coordinate detection part shown in FIG. I will only explain the operation.

When the horizontal direction minute distance data Δ5illθ is supplied from the scan converter 60 to the coordinate detection unit 10 and the timing pulse CK1 is supplied from the clock control unit 51, the register 11 shown in FIG. 2 takes in this data, and then The captured data is held until the clock pulse CK1 is supplied. This clock pulse CK
I! -m It is now generated every sweep and vice versa. Therefore, the captured data is retained while the sweep is being performed from the center point to the outer edge as shown in Figure 9, and when the next sweep starts. At that point register 11
The data currently being supplied to the register is newly loaded into that register. Note that the vertical minute distance data Δfocus θ is taken into the corresponding register by a timing pulse CK3 having a timing different from the timing pulse CKI.

When the horizontal direction minute distance data Δ81nθ is taken into the register 11, the clock pulse CK2, which is the scan conversion clock of the scan converter, is supplied one after another.
This data is sent to adders 12, 14' and register 13.
is accumulated each time the clock pulse CK2 is supplied. At this time, the output signal 100 of the register 13 indicates the ideal coordinates of the dot within the pixel at that time, and the output signal 104 of the adder 12, which is obtained by adding Δsinθ to the value, indicates the dot to be displayed next, that is, If the dot of the output signal 100 is displayed as the mth dot (hereinafter, this dot is referred to as dot m), then the output signal 104
indicates the position of the (rnm+1)th displayed dot [hereinafter, this dot is referred to as dot (m+1)]. The carry signal 102 of the adder 12 is
1) has moved to another pixel, and the carry signal 101 of the adder 14 indicates that the (m+2)th displayed dot [hereinafter referred to as dot (m+2)] is the dot (m+1). This indicates whether or not the pixel has moved to another pixel. That is, during the transfer of the dot m, the coordinate detection unit 10 detects the dots (m+1) and (m+2)
A signal representing the positional relationship and ideal coordinates, that is, the position of the dot to be displayed, is output.

Among the signals output from the coordinate detection section 10, output signal 1
00 is supplied to the modulation degree setting section 20, and a carry signal 101
, 102 are supplied to the group selection section 50. Since the coordinate detection section 1G has two circuits as described above, the modulation degree setting section 20 is supplied with signals of type 2a, and the group selection section 50 is supplied with four types of signals.

The group selection unit 50 selects dots m, (m+1) = (m
+2) Outputs the display position of (1k) to (e) in Figure 4 using the signal shown in Table 1, and shows what the constituent dots look like at this time in Table 2. It outputs according to the signal shown in . Table 2 shows the states of the main line dot m and the supplementary line dots (m+1) and (m+2), where the main line dot m is the fcm-th dot mentioned above, and the scan converter 60 Since luminance data is supplied, when expressing the constituent dots, dot m is expressed as main line t)m.

Also, supplementary line dots) (m+1) and (m+2) refer to the (m+1)th dot and (m+2)th dot mentioned above, and these dots are actually determined by the composite brightness of the main line dot and this dot. The position observed in
This is to determine where within the pixel it should be placed. In this way, dots (m+1), (m+2)
Since these dots are auxiliary dots, when expressing constituent dots, these dots are expressed as supplementary line dots. however,
The supplementary line dots (m+1) and (m+2) may overlap, and the supplementary line dot (m+1) may overlap with the main line dot m. Note that classifying data as shown in Tables 1 and 2 based on the data supplied from the scan converter 60 is defined as case classification.

The modulation degree setting section 20 sets the dot m + (m) according to the ideal coordinate data of the dot m + (m
+1. ) + (m +2) The degree of modulation is set to determine what kind of difference is to be made in the brightness.

The display pattern in Fig. 4, as shown in Fig. al1, divides the pixel and sets the modulation degree, and the modulation degree is 1 from θ to 15.
There are 6 types to choose from.

Since the scan converter has 16 gradations, this is in accordance with its characteristics. The operation of this part is as follows.

One of the five types of display patterns shown in FIG. 11 is selected from the group selection section 50, and the display points A11 and B are dots m and (m+1).

(m+2) is indicated. at the same time,
The coordinate detection unit 10 outputs a signal representing the ideal coordinate position within the pixel indicated by a black circle in FIG. Modulation degree setting section 2
0, based on the above information, the degree of modulation of the display point is set by an inverse proportionality method using the ideal coordinates and the distances ra and rb to the actual display point. The setting at this time is such that the sum of the modulation degrees of each display point is 15, that is, the brightness is the same as the brightness of the display point at the maximum brightness. As a result, the ideal coordinates, that is, the apparent brightness of the display point is always displayed at a constant value.

The modulation depth is stored in the P-ROM and is set to 4 as shown in Figure 3.
For each group, output terminals for dots m, dots (m+1), and dots (m+2) are provided, and these are path-coupled for each type. The coordinate data of the ideal coordinates is input to each group as an address of the P-ROM, and the display state and configuration dot selection signal input by the group selection signal is input to the P-ROM.
It is input to the output enable and address of M.

The group of ROMs 21 to 23 for two-point modulation is a display state selection signal! + 7 +
m+2) is input as the address. Note that the signal m/(m+2) and the signal m/(m+1) have a positive/negative relationship between two-point modulation; if m 7m +2 is rOJ, the constituent dots are m and (m+2), and if rlJ, the constituent dots are m and m+
It becomes 1.

On the other hand, three-point modulations as shown in FIGS. 11(d) and (e) are grouped into one group in the ROM 24.

In this case, the constituent dot selection signal m/(m + 1)
/(m+2) becomes the output enable signal,
A display state selection signal 7-X is input to the address.

The signal F −X is the signal m/(m+2) and m/(
m + 1) has the same relationship with the signal (x-y), and if 7-1 is ``0'', the display state of (d) in Figure 11 is obtained, and if 7-1 is ``1'', then ( e) is displayed.

Through the above operations, one state is selected and each dot m
The modulation degrees of +(m+1) and (m+2) are determined.

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

Of these data, the data of dot (m+1) is directly supplied to the data converter 30, the data of dot (m+1) is sent via the shift register 56, and the data of dot (m+2) is sent via the shift register 54.55. The data is then supplied to the data conversion section 30. Then, the data converter 30 receives the simultaneously supplied dots m, (m+1)a, (m
+2) Select the maximum luminance data from the data b and send it to the selector 53.

Of the data selected at this time, dot (m+1)
Since the data of a is passed through the shift register 56, the processing time is delayed by one processing time compared to the data of (dra)m. That is, when a dot (m-1) that is one processing step before dot m is displayed, the data is determined assuming that the dot m is one step ahead of dot m. Therefore, the data directly supplied from the brightness setting section 52 to the terminal C of the data conversion section 30 is also transmitted to the shift register 5.
The data supplied through the dot 6 is also data representing the brightness of the dot m. Similarly, shift register 54
．． The data supplied to the data conversion unit 30 via the dot 55 is data determined assuming a dot that is two processing points from that point when displaying the dot (m-2). This is data representing the brightness of m.

In other words, when the modulation degree setting unit 20 displays the drum) (m
Three types of data (+2) data are being sent, but these dots (m+1) are - processing parts, dots) (m+2)
) is delayed by the processing time of two processes.

Therefore, the data sent from the data converter 30 at the timing of displaying dot m is only the data of dot m.

As a result, the selector 53 is given the data that has passed through the data converter 30 and the luminance data of class 2a, which is the data that is sent out from the scan converter 60. Then, one of these data is selected and sent out according to a signal supplied from the smoothing control unit 40.
It is displayed on a display section (not shown). At this time, when data from the data converter 30 is selected, display smoothing is performed.

In this way, by displaying the output from the data converter 30, the outline can be displayed as a smooth line. However, smoothing is nothing but changing the brightness of each dot, so if you apply this kind of smoothing to all data, uneven brightness will occur in certain areas, making it look unsightly. .

Therefore, this inconvenience can be avoided by performing smoothing only on areas where the brightness changes and not performing smoothing on areas where the brightness does not change. A smoothing control section 40 shown in FIG. 5 performs such control.

As shown in Fig. 7(a), the screen that is displayed now is composed of parts indicated by symbols A, 22, B, and C, and the brightness of each part is different, and the sweep is performed in the direction shown by the arrow. An example will be explained below. When the data of dot B is supplied to the terminal A of the comparator 42, the terminal B of the comparator 42 is set to 1 by the latch 41.
Data delayed by a clock, that is, data of driver A is supplied. If the comparator 42 is configured to generate a "1" level output when the data at terminal B differs from the data at terminal B, then in this case, since dot A and dot B have different luminances, the comparator 42 4
2 generates a "1" level output signal. This data is taken into the shift register 43, and terminals QA and Qi+
Since the signal is sent from the selector 5 via the OR circuit 48,
It is supplied to the terminal S of No. 3. Selector 53 connects terminal S to rl
When a J level signal is supplied, terminal B of selector 53
If the signal at terminal A of the selector 53 is set to be output when the signal at rOJ level is output and the signal at rOJ level is supplied, the data at dot B will be supplied from the data converter 30 to terminal B of the selector 53. The data that has been smoothed is output. In this way, the initial timing of smoothing is determined.

The smoothing period is determined as follows.

Smoothing can be done by 2 dots or 3 dots as shown in Figure 4.
This is done by controlling the brightness of the dots. Therefore, when performing smoothing, it is necessary to perform smoothing processing continuously for a maximum of three dots. Since the initial stage of smoothing is determined as described above, the period of smoothing can be determined by determining the final stage of smoothing. The period determined by the above operation is for two dots, but as mentioned above, it may be necessary to smooth the period for three dots, and in that case the process will be as follows.

Since the signal corresponding to each dot for smoothing is generated from the group selection section 50 as described above, the end of smoothing when three dots are required can be determined based on this signal. The group selection unit 50 determines whether the dots to be smoothed are dots m r (m +
1) + (m+2) A signal m/m+2 is sent out to indicate which dot it is. Both indicate that a smoothing period of 3 dots is required. Therefore, if these signals are outputted via the OR circuit 46, this signal will be generated for one dot at the smoothing start time. By taking this into the shift register 44 and outputting it from the second and third stages, it is possible to obtain a signal for outputting smoothed data for the second and third dots as well. This signal is sent to the selector 53 via the OR circuit 47°48.
Therefore, the data outputted from the period data converter 3G for three dots is outputted from the selector 53.

Therefore, in Fig. 7 (a) iC the drums indicated by black circles) B, C
DK smoothing is performed.

When dot E is displayed, the input data to comparator 42 are the same, so comparator 42 does not generate an output signal. Therefore, the output signal from the group selection section 50 is masked by the AND circuit 49 and is not sent out. Therefore, since the output signal of the OR circuit 48 is at the "0" level, the data that has not been subjected to the smoothing process and is output from the scan converter 60 is output. Therefore, an image with a large area can be displayed with uniform brightness without causing uneven brightness.

In the case of FIG. 7 (J&), since dots A and B have different luminances, the comparator 42 continuously generates two dots. Therefore, the output signal of the first stage of the shift register 43 alone provides a signal for two dots. However, as shown in FIG. 7(b), when the brightness differs between the symbol A and the symbol opening, the boundary between the brightnesses is a line with no width. An output signal can only be generated when For this reason, the output signal of the OR circuit 49 is used.

If fC3 dots are required, the output signal of the shift register 44 is secured for three dots using the OR circuit 48.

Note that actual images often have brightness changes expressed by a normal distribution as shown in FIG. Since the method described so far applies to the case where the width shown in FIG. 8 is not zero, there is a problem when trying to realize a smooth luminance change. In this case, by setting n to a positive value, performing smoothing when D > n, and setting the value of n according to the brightness levels a and b in Figure 8, a smoother change in brightness can be achieved. I can do it. In this case, the comparator 42 may be replaced with a ROM that stores a preset value of n.

〔Effect of the invention〕

As explained above, this invention controls the brightness of adjacent display points to make it appear that parts other than the actual display points are being displayed, so the outline of the image is displayed as a smooth line. This has the effect of providing an easy-to-read screen.

[Brief explanation of drawings]

Fig. 1 is a block diagram showing an embodiment of the present invention, Fig. 2 is a block diagram of the coordinate detection section, Fig. 3 is a block diagram of the modulation degree setting section, and Fig. 4 shows the positional relationship of each dot. Figure, 8
Figure 5 is a block diagram of the smoothing control section, Figure 6
The figure shows the modulation characteristics written in the brightness setting section.
Figure 8 shows the brightness characteristics with normal distribution, Figure 9 shows the screen displayed using polar coordinates, and Figure 10 shows the screen displayed using mask scan display. Diagram showing the displayed screen, No. 11
The figure is a diagram □ for explaining the method of setting the modulation degree. 1...Sweep line, 3...Reference point, 4...
Scanning line, 5... Display start point, 10... Coordinate detection section, 20... Modulation degree setting section, 30... Data conversion section, 40. Meeting... Smoothing control section, 50.
Function: group selection unit, 51: function: clock control unit, 52: brightness setting unit, 53: function selector, 54-56: shift register.

Claims (1)

[Claims] In a video display method that converts a video signal from a polar coordinate display method to a raster scan display method and displays video by a set of multiple display points, an adjacent preceding display point adjacent to the display point to be displayed in the preceding display direction is used. A point and the next adjacent preceding point that is further adjacent in the preceding display direction from the adjacent preceding point, existing within a square assumed in the preceding display direction with the distance between the adjacent scanning lines from the display point to be displayed as one side. A video display method characterized in that the brightness of a preceding display point to be displayed and a point to be displayed is controlled based on display position data in a polar coordinate display system.