JPH0392899A - Image processor - Google Patents

Abstract

PURPOSE:To alter the shape of an end point without sacrificing speed by providing a brightness modulation degree generating table generating a brightness modulation degree from coordinates of a dissolved pixel and its inclination, brightness modulating circuits and a frame memory holding a finally displayed brightness. CONSTITUTION:The brightness modulation degree generating table 3 generating the brightness modulation degree from the coordinates of the dissolved pixel and its inclination, the brightness modulating circuits 4l to 4n, and the frame memory 5 holding the finally displayed brightness compose the image processor. By providing the brightness modulation degree generating table 3, the brightness of an end point in a complicated shape can be modulated, and simultaneously the table 3 is used for a high speed memory. Thus, deterioration in performance is prevented, and the shape of the end point can be arbitrarily altered without modifying hardware because the memory is employed.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention is a Lascous scan-type two-dimensional image processing system that has a graphic processing function that can obtain an image closer to the original image by applying brightness modulation to the displayed graphic. The present invention relates to a dimensional or three-dimensional image processing device.

[Conventional technology]

Patent No. 12 was filed earlier by the present applicant as a countermeasure against the step-like jaggedness peculiar to conventional Rusk scan type graphic display devices.
A line smoothing method by brightness modulating a plurality of beams has been devised as shown in No. 25686 and No. 1249199. Further, as the basis for brightness modulation, there is a method based on coordinates generated by line segment interpolation, and an area method based on the proportion of a line segment with width within a certain pixel area, in which a line segment is given a width. The pixel area is assumed to be a square whose side is the distance between adjacent pixels (Figure 4). The circles in FIG. 4 indicate the modulation degree of the pixel. The smaller the circle, the darker the modulation will be. [Problem to be Solved by the Invention] The above technique is effective for the center portion of a line segment, but there is no clear idea regarding the end point portion.

If the end affected area is treated as an extension of the central part, it will be cut in the vertical and horizontal directions, and the more the angle becomes 45 degrees, the more conspicuous the cut shape at the end point will be (Figure 6). In particular, in the DDA method, which generates pixels based on one major direction, the difference in the shape of the section between 45 degrees becomes noticeable, and there are also missing parts in polygons etc.
figure).

Furthermore, if this algorithm is fixed by hardware, it will be difficult to handle changes in the shape of line segments. Another disadvantage is that relying on software inevitably reduces speed.

The purpose of the present invention is to realize end points that have a constant shape no matter which direction a line segment is drawn, and to change the shape of the end points without changing the hardware or causing performance degradation such as speed reduction. be.

[Means to solve the problem]

In view of the above points, the present invention provides coordinates and brightness of the starting and ending points of the line segment to be displayed. and a preprocessing unit that generates a slope, a line segment interpolator that decomposes the line segment into pixel coordinates, a brightness modulation degree generation table that generates a brightness modulation degree from the decomposed pixel coordinates and the slope, and the brightness modulation. It consists of a brightness modulation circuit that generates the final displayed brightness from the brightness and the brightness, and a frame memory that holds the final displayed brightness, and has a brightness modulation degree generation table. By performing brightness modulation of complex shapes and at the same time using high-speed memory for the table, performance degradation was prevented, and since it was memory, the shape of the end points could be changed as desired without changing the hardware.

[Function] The use of the luminance modulation degree generation table as described above provides the following advantages.

(2) End points of a constant shape can be obtained regardless of the lit image direction. When an operation such as moving a line segment is performed in the image processing device, as the direction of the line segment changes, the unnatural shape of the end point does not become noticeable. Furthermore, even when a circle is approximated and displayed as a polygon, there will be no breakage in the connecting portions of line segments at 45 degrees (FIG. 8).

■ In a raster scan type display device, the minimum unit of display is one pixel, and display with a resolution smaller than this is not possible. However, with brightness modulation called line smoothing, it is possible to display images in units that are smaller than they appear. (In units of nub pixels. FIG. 9) If this sub-pixel is also applied to end points, the entire line segment can be displayed with a high resolution of less than 1 pixel.

In FIG. 9, Pn (n=1.2.-) is a pixel area, which is a square with a length of one pixel. In the area method, a line segment is defined as a frequency region 6 with a width, and the modulation degree of a certain pixel region can be expressed as a proportion An (n=1.2, 1.-) occupied by the region 6. Therefore, by using this ratio An, subpixels including end points can be expressed.

■ As mentioned before, give width to line segments,
The degree of brightness modulation is determined by the proportion of the width line segment to one pixel, but by changing the width setting, lines with a width of one pixel or more can also be displayed (Figure 1O).

(2) The present invention, which allows the end points to have arbitrary shapes, can be applied as shown in FIG. In FIG. 10, a region 7 is shown in which the line segment has a width plus a region 7 in which the end point has an arbitrary shape, and each pixel region Pn (n=
l, 2. −1 and the proportion of area 7 within it An
The modulation degree is determined by (n=1, 2,).

Also, if you use the mode as table power, you can use multiple shapes at the same time.

In FIG. 11, 8 is a case where the end points are squares, and characters 9 and 10 are shown as examples. Also, 1l is when the end point is a circle,
Characters 12 and l3 are shown as examples.

〔Example〕

Hereinafter, the present invention will be explained based on illustrated embodiments. 1st
The figure is a Bronnoch diagram for implementing the present invention. l is a preprocessing unit that captures the parameters necessary for line segment interpolation, and outputs the line segment brightness I, the X component Xs and Y component Ys of the starting point,
X component Xe and Y component Ye of the end point, and slope tan of the line segment
There is θ.

2 is the above XS, "1's, Xe, Ye and t
This is a line segment interpolator that decomposes a line segment into pixels by anθ. The line segment interpolator 2 compares the displacement amount of each X component and Y component of the starting point and the collar point, and takes the displacement amount with the larger absolute amount as a measure. One point on the line segment is found by adding tanθ or l/tanθ when this major component is increased or decreased by 1. The coordinates of this sequence of points arranged at intervals of l pixel length in one major direction are output as J (major weight) and N (minor weight).

3 is a brightness modulation degree generation table which is the key to the present invention,
Said J,N. Table reference is performed using tanθ and a MODE signal for table control. High-speed memory is optimal for the table, allowing modulation degrees based on complex equations such as line segments and circles to be obtained without degrading performance. The contents of the table will be described later. In this embodiment, the table output is the modulation degree Ln for 3 pixels. Lm
I wrote L1, but of course there can be any number of outputs. Lm has the coordinates of the point sequence. or the nearest pixel, and the pixels above and below it are Ln. It is modified by applying a modulation factor called LE.

4n. 4m, 41 are the line segment luminance ■ and the luminance modulation frequency Ln.
Lm. This is a brightness modulation circuit that generates energy by multiplying Li2 by the maximum brightness In, lm, 11 after modulation. This brightness modulation circuit may also be increased or decreased depending on the width μ of the line segment without any problem in the present invention.

5 is the final brightness In. This is a frame memory that holds lm, ①1. This memory 5 is displayed as an image, and the coordinates J. At the same time as receiving N as the address of the final luminance lm, In,
For In, add offset and then address,
Write each.

FIG. 2 explains the contents of the luminance modulation degree table 3. Pn. Pm. P1 are the above-mentioned Ln and Lm, respectively.
,Lj! This is a pixel area corresponding to , and one pixel area is a square with each side having a length of 1 pixel. It is assumed that the line segment crosses the pixel area Pm, and its coordinate values are the above-mentioned locus IIJ. It is N.

In the case where it is not the end point of a line segment, J may be fixed at the center of the pixel area, and the locus lj! in the minor direction! N and tanθ
Even if the brightness modulation degrees Ln, Lm, and L1 are input into the brightness modulation degree table 3 using only the brightness modulation degrees Ln, Lm, and L1. This is the modulation degree based on the area method, but as long as it is a table, the modulation degree may be based on another algorithm.

FIG. 3, like FIG. 2, explains the contents of the brightness modulation degree table 3, but in the case of the end points of a line segment. The end point is in the pixel area Pmz, Pnz , P 1 H
At the same time, Pn+. is modulated due to the shape of the end points.
It is also necessary to modulate pm, , P 11 and Pn, , Pm, , Pf. This (PnP rn1, P l l
) and (P n z. P m2, P 1 z ) and (
Pn3, Pm,, P1*), the coordinates J, N
, the slope tanθ and the MODE signal perform table access.

〔Effect of the invention〕

As is clear from the above description, by having a brightness modulation degree table, the present invention can obtain line segments with line smoothing applied to end point shapes, and can also add end points of other shapes to the contents of the table. By adding different line widths, line segments of arbitrary shapes can be obtained without deteriorating performance. It has the excellent feature that it can express up to the level of sub-pixel without being limited by the size of a pixel, and that the shape of a line segment facing in any direction can be obtained equally.

[Brief explanation of drawings]

FIG. 1 is a professional diagram showing an embodiment of the image processing apparatus of the present invention, and FIG. Figure 3 is a diagram explaining the concept of brightness modulation at a line segment that is not an end and at an end using the area method, respectively.
The figure is a diagram for explaining conventional line smoothing, FIG. 5 is a diagram showing a case where line smoothing is applied in the image processing apparatus of the present invention, and FIG. 6 is a diagram for explaining conventional line smoothing.
A diagram showing the intercept shape when one major direction changes by 5 degrees,
FIG. 7 is a diagram showing a part of a polygonal approximation circle in the prior art, and FIGS. 8(A) and 8(B) are respectively section shapes when one major direction changes by 45 degrees in the image processing apparatus of the present invention. FIG. 9 is a diagram illustrating sub-pixels at end points in the present invention, and FIG.
Figure 0 is a diagram explaining the arbitrary shape and arbitrary end point shape in the present invention, Figures 11 (A), (B), and (C) are diagrams showing examples when the end point shape in the present invention is rectangular, and Figure 1
1 (D), (E), and (F) are diagrams showing examples in which the shape of the end point in the present invention is circular. l ・ ・ ・ 2 ・ ・ ・ 3 ・ ・ ・ 4n, 4 5 ・ ・ ・ Preprocessing section line segmenter brightness modulation degree generation table m, 4n...brightness modulation circuit frame memory or more

Claims (1)

[Claims] a preprocessing unit that generates the starting point coordinates, end point coordinates, brightness, and slope of a line segment to be displayed; a line segment interpolator that decomposes the line segment into pixel coordinates; and a brightness modulation degree based on the decomposed pixel coordinates and slope. a brightness modulation circuit that generates the brightness to be finally displayed from the generated brightness modulation degree and the brightness, and a frame memory that holds the brightness to be finally displayed. An image processing device comprising: