JP2532596B2 - Fluoroscopic image display device - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fluoroscopic image display device that displays a fluoroscopic image.

2. Description of the Related Art In recent years, fluoroscopic image display devices have become more and more important as computer-aided design and computer graphics have advanced.

An example of the above-mentioned conventional perspective image display device will be described below with reference to the drawings. FIG. 4 shows the structure of a conventional fluoroscopic image display device. The operation will be described below.

First, the object data processing unit 41 creates object data that characterizes the object to be displayed, and stores it in the object data memory unit 42. Examples of the object data include the positions of vertices representing the shape of the object and the connection relationship between vertices, sides, and faces.

Next, in the image generation unit 43, the object data in the object data memory unit 42 is perspective-projected on the display screen, and then the hidden object erasing process in which the object in the front hides the distant object and the projection to each pixel of the display screen Image generation including brightness calculation processing for calculating the brightness of the object surface is performed, stored in the image memory 44, and the brightness of each pixel is read from the image memory 44 according to the synchronization signal and displayed on the display unit 45.

However, in the above-mentioned configuration, when the direction of the line of sight changes, it is necessary to again perform perspective projection of the object data by the image generation unit 43 to generate an image.

In view of the above problems, it is an object of the present invention to provide a perspective image display device capable of displaying a perspective image without re-performing perspective projection of object data and image generation even when the direction of the line of sight changes.

Means for Solving the Problems In order to solve the above problems, a perspective image display device of the present invention stores an image center-projected in the cylinder circumferential direction and perspective-projected in the cylinder axis direction on a cylindrical surface centered on a viewpoint. A perspective image is displayed on the display screen by inputting an image memory unit to be stored, a scroll position signal indicating the position on the cylindrical surface corresponding to the center position of the display image, a horizontal position signal and a vertical position signal of the display image. The read address generating unit for outputting the horizontal position signal and the vertical position signal of the corresponding pixel read position from the image memory unit is provided.

Effect The present invention has the above-described configuration, when the direction of the line of sight is changed, the perspective projection of the object data and the display of the perspective image, which requires re-execution of the image generation, are changed to the corresponding images for displaying the perspective image. By obtaining the pixel read position from the memory unit, it is possible to display a perspective image without performing perspective projection of object data and re-execution of image generation.

Example A perspective image display apparatus according to an example of the present invention will be described below with reference to the drawings.

FIG. 1 shows the configuration of a perspective image display device according to an embodiment of the present invention. In FIG. 1, the image memory unit 1 stores an image that is center-projected in the cylinder circumferential direction and perspective-projected in the cylinder axis direction on a cylindrical surface centered on the viewpoint. The screen address generator 2 outputs a horizontal position signal 11 and a vertical position signal 12 of a display image in synchronization with a synchronization signal 10 input from the outside. The scroll position signal 13 is input from the outside to determine the direction of the line of sight and indicates the position on the cylindrical surface corresponding to the center position of the display image. The read address generation unit 3 inputs the display screen horizontal position signal 11, the display screen vertical position signal 12, and the scroll position signal 13, and determines the pixel read position from the corresponding image memory unit 1 for displaying a perspective image on the display screen. A horizontal position integer part signal 14, a vertical position integer part signal 15, a horizontal position decimal part signal 16 and a vertical position decimal part signal 17 are output. The luminance-weighted average unit 4 inputs the luminance signals 21, 22, 23, 24 of the four peripheral pixels around the position indicated by the horizontal position integer part signal 14 and the vertical position integer part signal 15 from the image memory unit 1 and The luminance signal is weighted and averaged according to the position fractional part signal 16 and the vertical position fractional part signal 17, and the luminance signal 25 is output.

Regarding the perspective image display device configured as described above,
The operation will be described below with reference to FIGS. 1, 2, and 3.

First, FIG. 2 shows the positional relationship between the viewpoint, the cylindrical surface, and the display screen. In FIG. 2, an image that is center-projected in the cylinder circumferential direction and perspective-projected in the cylinder axis direction on the cylindrical surface 31 with the viewpoint 30 as the center is generated and stored in the image memory 1.
The line of sight 34 extends from the viewpoint 30 in the direction indicated by the scroll position 33. Display screen at the intersection of line of sight 34 and cylindrical surface 31
There are 32 center points.

Next, FIG. 3 shows the correspondence between the image memory and the display screen. The position indicated by the scroll position 33 of the image memory 1 corresponds to the center position of the display screen.

The horizontal position of the display screen with the center position of the display screen 32 as the origin is X, the horizontal position of the image memory 1 is θ, and the scroll position 33 is θ.
_{Letting C} be the distance between the viewpoint 30 and the display screen 32, the following relationship holds: X = t · tan (θ−θ _C ).

If the vertical position of the display screen with the center of the display screen 32 as the origin is Y and the vertical position of the image memory 1 with the center of the image memory 1 as the origin is y, then Y = y / cos (θ−θ _C ). The relationship is established.

Therefore, when the read address generator 3 receives θ _C from the scroll position signal 13, X from the display screen horizontal position signal 11, and Y from the display screen vertical position signal 12, the read horizontal position θ from the image memory unit 1 is obtained. The read vertical position y is obtained by the following calculation.

The horizontal position integer part signal 14 is set to the integer part θ _I of the read horizontal position θ,
The decimal part θ _F is output to the horizontal position decimal part signal 15, respectively.
The integer part y _I of the read vertical position y is output to the vertical position integer part signal 16 and the decimal part y _F is output to the vertical position decimal part signal 17, respectively.

If the luminance signals of the pixels at the positions indicated by the horizontal position integer part signal 14 and the vertical position integer part signal 15 from the image memory unit 1 are directly used for display, the contour of the displayed object becomes discontinuous and continuous. Even if the scroll position 33 is changed to, the displayed image does not change continuously.

In this embodiment, in order to solve the above problem, a weighted average of luminance is performed. Horizontal position integer part θ _I and vertical position integer part y _I
Positions (θ _I , y _I ), (θ _I +1, y _I ), (θ _I ,
_{y I +1), (θ I} + 1, y I +1) pixels, respectively the luminance of the
Assuming that I ₁ , I ₂ , I ₃ , and I ₄ , the weighted average luminance I is I = (1-y _F ) {(1-θ _F ) I ₁ + θ _F I ₂ } + y _F {(1-θ _F ) I ₃ + θ _F I ₄ }.

Therefore, in the luminance weighted average unit 4, the first read luminance signal
21, the second read luminance signal 22, the third read luminance signal 23, and the fourth read luminance signal 24, respectively I ₁ , I ₂ , I ₃ , I _4, and the horizontal position decimal part signal 16 θ _F , vertical position When y _F is given by the decimal part signal 17, the weighted averaged luminance I is obtained, and the luminance signal
Output to 25.

When the direction of the line of sight 34 changes, the scroll position 33 is changed correspondingly, and the image perspective-projected onto the screen corresponding to the changed line of sight is read from the image memory 1 and displayed. In this case, perspective projection of the object data and image generation are not required.

As described above, according to the present embodiment, an image memory unit for storing an image center-projected in the cylinder circumferential direction and perspective-projected in the cylinder axis direction on the cylindrical surface centered on the viewpoint, and the center position of the display image. Corresponding pixel read position from the image memory section for inputting a scroll position signal indicating a position on the cylindrical surface and a horizontal position signal and a vertical position signal of a display image to display a perspective image on a display screen. By providing a read address generation unit that outputs the horizontal position signal and the vertical position signal of the object data, even if the direction of the line of sight changes, the change does not require the perspective projection of the object data and the re-execution of the image generation. A perspective image corresponding to the line of sight can be displayed.

EFFECTS OF THE INVENTION As described above, according to the present invention, an image memory unit for storing an image center-projected in the cylinder circumferential direction and perspective-projected in the cylinder axial direction on a cylindrical surface centered on a viewpoint, and a central position of a display image Corresponding pixel read position from the image memory section for inputting a scroll position signal indicating a position on the cylindrical surface and a horizontal position signal and a vertical position signal of a display image to display a perspective image on a display screen. By providing a read address generation unit that outputs the horizontal position signal and the vertical position signal of the object data, even if the direction of the line of sight changes, the change does not require the perspective projection of the object data and the re-execution of the image generation. A perspective image corresponding to the line of sight can be displayed.

[Brief description of drawings]

FIG. 1 is a block diagram of a perspective image display apparatus according to an embodiment of the present invention, FIG. 2 is a conceptual diagram of a viewpoint, a cylindrical surface and a display screen in the embodiment of FIG. 1, and FIG. 3 is an implementation of FIG. FIG. 4 is a conceptual diagram of an image memory and a display screen in the example, and FIG. 4 is a configuration diagram of a conventional perspective image display device. 1 ... Image memory section, 2 ... Screen address generation section, 3 ...
... Read-out address generation section, 4 ... Luminance weighted average section.

Claims (2)

(57) [Claims] 1. An image memory unit for storing an image perspectively projected onto a cylindrical surface centering on a viewpoint, a scroll position signal indicating a position on the cylindrical surface corresponding to a central position of a display image, and a display image. The image corresponding to the horizontal position signal and the vertical position signal of the image read out from the image memory unit for displaying the perspective image on the display screen is enlarged as the distance from the center position of the screen increases in the horizontal direction. A perspective image display device comprising: a read address generation unit that outputs a horizontal position signal and a vertical position signal of a pixel read position from a memory unit. 2. A screen address generation unit for outputting a horizontal position signal and a vertical position signal of a display image in synchronization with a synchronization signal input from the outside, and an image perspectively projected on a cylindrical surface centering on a viewpoint. An image memory unit to be stored, a scroll position signal indicating a position on the cylindrical surface corresponding to the center position of the display image, a horizontal position signal and a vertical position signal of the display image are input, and a perspective image is displayed on the display screen. The horizontal position integer part signal and the horizontal position decimal part of the corresponding pixel read position from the image memory part so that the image read out from the image memory part for display enlarges as it moves away from the center position of the screen in the horizontal direction. Signal, a vertical position integer part signal, and a vertical position decimal part signal, and a read address generating part, and four pixels around the image memory position indicated by the horizontal position integer part signal and the vertical position integer part signal. Fluoroscopic image display apparatus characterized by comprising a brightness weighted average unit for outputting a fluoroscopic image luminance signal subjected to the weighted average of the luminance signal in accordance with the lateral position fractional part signal and the vertical position fractional part signal inputted luminance signal.