Three-dimensional image output device and background image generation device

A background image generation device that generates a background image for a three-dimensional image in which an object is drawn three-dimensionally with a background thereof, the three-dimensional image being a three-dimensional map that expresses a geographical shape three-dimensionally and includes a ground surface and features, the background being located behind the object in a three-dimensional space, the background image including a transparent portion through which an image is seen and an opaque portion which blocks a view,

• the background image generation device comprising:
• an object drawing range input section that inputs information specifying an object drawing range for drawing the object three-dimensionally as a three-dimensional object image on which the background image is to be superimposed;
• a background specifying information input section that inputs information specifying a content of the background of the three-dimensional object image in the three-dimensional image;
• and
• a background image generator that generates the background image by forming the opaque portion which covers and hides part of the object drawing range with the specified content of the background, while forming the transparent portion with a residual area of the opaque portion, the background image being superimposed in front of the three-dimensional object image contrary to an actual location of the background behind the object in the three-dimensional space,
• wherein the background image has the opaque portion in an upper part of the background image, and the transparent portion in a lower part of the background image,
• wherein a boundary between the transparent portion and the opaque portion is expressed by a circular arc or an elliptical arc connecting a left side and a right side of the background image, the opaque portion showing the stratosphere of the earth,
• and wherein the projecting section generates the three-dimensional object image having the part covered and hidden by the opaque portion from a viewpoint position where a horizon is to be recognized as a curved line.

A three-dimensional image output method performed by a computer to output a three-dimensional image in which an object is drawn three-dimensionally with a background thereof, the three-dimensional image output method comprising:

• storing a three-dimensional model representing a three-dimensional shape of the object, the three-dimensional model including map data representing three-dimensional shapes of ground surface and features;
• generating, from the three-dimensional model, a three-dimensional object image that expresses the object three-dimensionally;
• generating a background layer including a background image for the three-dimensional image, the background image having a transparent portion and an opaque portion;
• and
• superimposing the background layer with the three-dimensional object image by arranging the background layer in front of the three-dimensional object image contrary to the a location of the background behind the object in the three-dimensional space, thereby generating the three-dimensional image which is a three-dimensional map that expresses a geographical shape three-dimensionally;
• and
• outputting the three-dimensional image,
• wherein at least one of respective conditions for generating the three-dimensional object image and generating the background layer is adjusted to cause the opaque portion of the background image to cover and hide part of the three-dimensional object image,
• wherein the background image has the opaque portion in an upper part of the background image, and the transparent portion in a lower part of the background image,
• wherein a boundary between the transparent portion and the opaque portion is expressed by a circular arc or an elliptical arc connecting a left side and a right side of the background image, the opaque portion showing the stratosphere of the earth,
• and wherein the projecting section generates the three-dimensional object image having the part covered and hidden by the opaque portion from a viewpoint position where a horizon is to be recognized as a curved line.

A background image generation method performed by a computer to generate a background image for a three-dimensional image in which an object is drawn three-dimensionally with a background thereof, the three-dimensional image being a three-dimensional map that expresses a geographical shape three-dimensionally and includes a ground surface and features, the background being located behind the object in a three-dimensional space, the background image including a transparent portion through which an image is seen and an opaque portion which blocks a view, the background image generation method comprising:

• inputting information specifying an object drawing range for drawing the object three-dimensionally as a three-dimensional object image on which the background image is to be superimposed in the three-dimensional image;
• inputting background specifying information specifying a content of the background of the three-dimensional object image in the three-dimensional image;
• and
• generating the background image by forming the opaque portion which covers and hides part of the object drawing range with the specified content of the background, while forming the transparent portion with a residual area of the opaque portion, the background image being arranged in front of the three-dimensional image contrary to a location of the background behind the object in the three-dimensional space,
• wherein the background image has the opaque portion in an upper part of the background image, and the transparent portion in a lower part of the background image,
• wherein a boundary between the transparent portion and the opaque portion is expressed by a circular arc or an elliptical arc connecting a left side and a right side of the background image, the opaque portion showing the stratosphere of the earth,
• and wherein the projecting section generates the three-dimensional object image having the part covered and hidden by the opaque portion from a viewpoint position where a horizon is to be recognized as a curved line.