JPS63172384A - Through-vision projection system - Google Patents

Abstract

PURPOSE:To improve the operability and also to reduce an error with a through- vision projection system by realizing the through-vision projection control using a parameter accordant with the human sense. CONSTITUTION:A display area 107 is decided by a screen reference line 125 for a triangle 124 which is defined by a visual point 102 and the line 125 on a plane including said line 125 and a visual center line 126. Thus the size of the area 107 is kept constant as long as the length 130 of the line 125 is kept constant. The relationships among picture angles 123 and alpha, the visual distance 122lv and the screen standard line length L130 are shown in an equation I. Then equations II and III are obtained from the equation I. In this perspective sense control mechanism, the control of only the perspective sense is possible with the same principle as conventional one excepting a fact that the display area moves.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to graphic display by a computer, and particularly to a perspective projection control method suitable for manipulating perspective and obtaining an image desired by a user.

[Conventional technology]

Conventional perspective projection control is defined by CORE, a graphic standard established by ACM Slggraph in 1979, or GKS by the International Organization for Standardization (ISO). . Regarding graphic display devices with a perspective projection mechanism, for example, Seiko Electronics Industry GR3
An example of this is the description in the 000 system manual.

[Problem that the invention seeks to solve]

In the above conventional technology, it is necessary to specify the following parameters for perspective projection control.

(a) Reference point at an arbitrary position in three-dimensional space (b) Viewpoint at a position based on the reference point (Q) Distance from the reference point to the projection plane (d) Direction of the projection plane (e) Upward direction (projection result is in a given direction, for example, the vertical direction, with respect to the screen) (f) Position and size of the display area (rectangle) on the projection plane Here, the behavior of the display screen when operating the main parameters will be explained using figures. FIG. 2 shows a reference point 101 defined in a figure definition coordinate system 100. A viewpoint 1021 given as a relative position from the reference point 101; a projection plane direction 103° defined by the figure definition coordinate system 101; an upward direction 104; a distance from the reference point 101 and a projection plane direction 1o3. Projection plane 105° projection plane coordinate system 106 determined from the upper direction 104. Projection plane coordinate system 106
As is clear from this figure, which shows the spatial arrangement of the display area 107 defined by.

Reference point! ! 101. Projection plane direction 103. upward direction 104
This decision can only be made after all of the above have been determined, and it is extremely difficult to make a decision.

FIG. 3 shows the display screen 110 due to changes in the relative positional relationship between the viewpoint 102 and the projection plane 105, and the size of the display area 107.
FIG. 2 is a diagram schematically showing the behavior of

In the figure, a three-dimensional figure Al 11. Figure B112
are each projected onto the projection plane 105, and within the display screen 110, the display figures Al13. 114 is obtained.

Although the display screen 110 is drawn with different sizes in FIGS. 1A, 2B, and 3C, it is ultimately mapped onto a physical screen of the same size.

In the same figure (b), the viewpoint 102 is set to the projection plane 1 with respect to (a).
05, and in terms of human motion, this is equivalent to ``looking closer to an object.''Intuitively speaking, ``closer figures appear larger, and distant objects also appear slightly larger.''
It is expected.

In other words, it is necessary to simultaneously enlarge one figure and emphasize perspective. However, in (b), the displayed figure A113゜same B1
Although the difference in depth between B14 and B14 is enhanced and the perspective meets expectations, the displayed figure B113 is rather small, resulting in a result that differs from human perception.

On the other hand, in the same figure (c), when the display area is reduced compared to (a), in terms of one person's action, it is equivalent to ``looking through a telescope'', and it is expected that ``the figure will appear larger''. . In the case of (c), there is no deviation from the human sense as shown in the figure, but as mentioned earlier, it makes no physical sense to define the display area 106 on a projection plane that is originally virtually provided. It is vague and ultimately distant from human senses.

As shown in the above two points, the conventional perspective projection control parameters are out of touch with the senses of a single human being, which makes it difficult to set the parameters and causes erroneous operations.

An object of the present invention is to enable perspective projection control using parameters that match human senses.

[Means for solving problems]

The above purpose is to set the projection control parameters according to the prior art as follows: (A) Reference point position with reference to the display target (B) Distance (sight distance M) and direction (#! Force direction EC) from the reference point to the viewpoint ) Direction of the projection plane (same as conventional (d)) (D) Up direction (same as conventional (e)) (E) Direction of the projection plane (same as conventional (e)) On the plane in the direction determined by the direction and the visual center line,
This can be achieved by setting the angle of view to have the viewpoint as the apex and the visual center line as the bisector. Furthermore, if (A) to (E) are operated individually, it is difficult to control only the perspective as shown in the conventional example shown in FIG. This control becomes possible by providing a perspective control mechanism that operates the angle of view 123 in conjunction with the angle of view 123.

[Effect]

The parameters (A) to (F) and the effects of the perspective control mechanism will be explained using figures. In Fig. 4.

The reference point 101 is determined based on the display target figure 120 (for example, the position of the center of gravity, the position of the vertex, etc.).

By giving viewing direction 121 and viewing distance 122.

A viewpoint 10-2 is determined. The projection plane 107 is the reference point 10
1 and is perpendicular to the projection plane direction 103. Here, when the upward direction 104 and the angle of view 123 are given, a straight line 128. A triangle 124 is determined from the viewpoint 102° and the viewing center line 126. however.

The apex angle (angle of view 123) at the viewpoint 102 is the visual center line 12
Let 6 be the bisector. A screen reference line 125 is determined from the triangle 124, and the display area 10 is determined from the screen reference line.
In the present invention, the display area 107, which was the most difficult to set in the prior art, can be set by the angle of view 123, and perspective projection control is possible. The operability is greatly improved.

FIG. 5 shows the behavior of the display screen depending on the manipulation of the viewing distance 122 and the angle of view 123. (b) is a case where the viewing distance 122 is made smaller than (a).

Display figure A113. Both 114 and 114 are large (and the depth is emphasized, and unlike the case in Fig. 3 (b), a result that matches the human sense is obtained. (c) is the case where the angle of view 123 is made small, The effect obtained is the same as that shown in FIG. 3(C), but the advantage is that the projection plane 105 can be controlled without being conscious of it.

Next, the operation of the perspective control mechanism will be explained using diagrams.

FIG. 6 shows a triangle 124 defined by the viewpoint 102 and the screen reference line 125 on a plane including the viewing center line 126 and the screen reference line 125. Since the display area 107 is determined based on the screen reference line 125, the display area 107 is determined based on the screen reference line 125.
If the length 130 of 25 is kept constant, the size of the display area 107 can also be kept constant. α, viewing distance 122Q
What is the relationship between v and screen reference line length 130?

however.

Reference point operation unit 131Ω of Ql two-screen reference line 125: Right side length 132 β: Screen reference [From the angle formed by 125 and visual center line 126, and.

(Equation 3), Fig. 6 (a) shows angle of view 123 = 45'', viewing distance 1
22 = 50, and in (b), if the angle of view 123 is set to 60 @ as a perspective operation, the 1-screen reference line length 130 remains constant, and the viewing distance 1Ii122 changes to 38.8 from the second equation, and the base The whole thing shifts to the left by 2.4. rj! As shown in I, the action of this perspective control mechanism is similar to that of conventional example No. 311 (
b) and the same except that the display area 107 moves.
-, and only perspective can be controlled.

Due to the parameters (A) to (E) and the effects of the perspective control mechanism, the operator can clearly understand the relationship between the operation and the behavior of the display screen, improving operability and preventing erroneous operations.

〔Example〕

Embodiments of the present invention will be described below with reference to the drawings. Figure 1 is 1
1 Water bag fi2, which is a block diagram of a three-dimensional graphic display device implementing the perspective projection method of the present invention, is connected to a host computer 1, and inside includes a graphic data storage section 3, a perspective projection processing section 41, a display control section 5, Display section 6. Reference point operation section 7. Projection plane direction operation section 8° upward direction operation section 9, viewing direction operation section 10. Viewing distance operation section 11, viewing angle operation section 12. Perspective operation section 13,
It is composed of a perspective control section 14. Here, 7 to 13 are collectively referred to as a perspective projection operation section.

Display processing of three-dimensional graphic data is performed in the following steps.

(a) Graphic data is transferred from the host computer 1 to the graphic data 1llf section 3.

(b) The perspective projection processing unit 4 takes out figure data from the figure data storage unit 5, generates projected figure data according to the projection parameters sent from the host computer 1 or the perspective control units 7 to 13, and displays the figure data to the display control unit. Send to 5.

(c) The display control section 5 displays the projected figure data on the display section 6.

(d) The following processing is activated by any one of a command from the host computer 1, a redisplay command from the operator, and a command to change perspective projection parameters by operating the viewing direction manipulation units 7 to 13, which will be described later.

Next, each of the perspective projection operation units 7 to 12 operates. The specification of perspective parameters will be explained.

In the reference point operation section 7, a reference point position is specified by an arbitrary spatial position such as a vertex center of gravity position based on a graphic element Bic, or by inputting a spatial movement amount. Figure 7 (a) shows cursor position 1
40 shows the figure vertex 141 being picked and the reference point 101 coincides with the figure vertex, and (b) shows how the reference point coincides with the spatial coordinates indicated by the two-dimensional cursor position 140.

The projection plane direction operation unit 8 selects three-point perspective, two-point perspective, etc., or inputs an arbitrary projection plane direction. In most cases, three-point or two-point perspective is used for perspective projection. For,
Automatically determining the direction of the projection plane by selecting the number of vanishing points is effective in improving operability. Figure 8 is a diagram showing the method of determining the projection plane direction using the number of vanishing points (however, it is assumed that most of the figures have surfaces parallel to and perpendicular to the axis of the figure definition coordinate system 100). The projection plane direction 103 is the visual center line 12
It is in the same direction as 6, and is generally a three-point perspective. (B)
is one axis of the figure definition coordinate system 100 and the visual center lllA12
7 is parallel to the vertical shadow line 150 on the projection plane 105,
This becomes the projection plane direction 103 for two-point perspective. In (c), the projection plane direction 103 is figure definition 4! It is in the same direction as one axis of the marker 100 and is for single point perspective.

(D) is a projection plane direction 127 that can be specified by arbitrary direction when the figure is oblique with respect to the figure definition coordinate system 100, and is specified by picking a figure element as a reference or inputting the amount of change in the projection plane direction. .

Upward operation section 9. Viewing direction operation unit 10. Viewing distance operation section 11
In the 1-view angle operation section, the value of each parameter or the amount of change thereof is input. FIG. 9 is a diagram showing an example of determining the display area 107 from the screen reference line 125 and the relationship between the upward direction 104. In (a), the display area 107 is connected to the screen reference line 12.
5 is the horizontal center line. This is an example of a rectangle having a predetermined aspect ratio. In this case, the screen reference line 125 is determined to be perpendicular to the projection 151 in the upward direction 107.

(b) is an example in which the one-screen reference line 125 is the diagonal line of the display area 107 similar to (a). It is determined to be perpendicular to a direction 152 rotated by an angle 153 formed by the axis.

The input from the perspective operation section 13 is interpreted by the perspective control section 14 as the amount of change in the angle of view. The perspective control section 14 is
From the screen base line length and the new angle of view obtained from the perspective projection processing section 4, the viewing distance is determined according to the second equation and sent to the perspective projection processing section 4.

According to this embodiment, changes in the screen due to changes in perspective parameters can be immediately confirmed. This has the effect of making it easier to select the number of vanishing points.

FIG. 10 shows an output diagram using the perspective projection method of the present invention.
The display screen 110 is square, the screen reference line 125 is the central horizontal axis of the screen, and the projection plane direction is parallel to the viewing center line (three-point perspective).If (a) is the standard state, (b) is the display target 12.
A diagram viewed “closer” to 0, that is, with a reduced viewing distance,
(C) is a diagram with a stronger sense of perspective based on the state of (B), (D) is a diagram with a weakened sense of perspective as well, and (E) is a diagram with a contrast to (B).
"Viewed from a distance", that is, a diagram with a larger viewing distance, (to)
(G) is a view "as seen through a telescope," that is, with a smaller angle of view, (G) is a view "as seen through a wide-angle lens," that is, with a larger angle of view, (C) is a view with the reference point 101 changed, (S) is a diagram in which the viewing direction has been changed. In both cases, a screen that matches the senses of a single person is obtained.

〔Effect of the invention〕

According to the present invention, perspective projection control can be performed with fewer parameters than in the prior art, and is suitable for one person's senses, so that it is effective in improving operability and, in particular, suppressing errors.

[Brief explanation of the drawing]

FIG. 1 is a configuration diagram of an embodiment of the present invention, FIG. 2 is a spatial layout diagram of perspective projection control parameters according to the prior art, FIG. 3 is an explanatory diagram of an example of perspective projection control according to the prior art, and the fourth @ is a book FIG. 5 is an explanatory diagram of an example of perspective projection control according to the present invention, and FIG. 6 is a diagram showing the principle of perspective control. FIG. 7 is an explanatory diagram of an example of specifying the reference point position, and FIG. 8 is an illustration of a reference point position specification example. 100... Figure definition coordinate system, 101... Reference point. 102... Viewpoint, 103... Projection plane direction, 104...
...Upward direction, 105... Projection plane, 107... Display area. 110... Display screen, 121... Vision direction, 122...
... Viewing distance, 123... Angle of view, 125... Screen reference line, 126... Viewing center line.

Claims (1)

[Scope of Claims] 1. In a graphics processing system that projects and displays graphic data defined in a three-dimensional space on a two-dimensional screen, the graphic data is projected and displayed in the same three-dimensional space around a viewpoint in the three-dimensional space. When projecting onto a projection plane in space and displaying a projected figure in a closed area having a predetermined shape on the projection plane on the two-dimensional screen, a part or part of the figure data is displayed in the three-dimensional space. One point defined as a reference point for all is a reference point, the viewpoint is determined by the distance and direction from the reference point, and the projection plane is a plane including the reference point and having a normal line set by a predetermined method. defining the display area on the projection plane as a straight line that is on the projection plane, includes a reference point, and forms a predetermined angle with a perspective projection image of a vector given in three-dimensional space; and the reference point, the viewing distance, the viewing direction, and the direction of the projection plane when determining the side of the triangle defined by the apex angle at the viewpoint, with the straight line connecting the viewpoint and the reference point as a bisector, with respect to the viewpoint. A perspective projection method characterized by performing projection control based on , upward direction, and angle of view.