摘要:
A method and apparatus for simulating the effect of non-homogeneous fog in an image displayed on a screen. The image is intended to represent the appearance of a model defined in a database in world space coordinates from an eyepoint position in world space, the model being defined in terms of individual features each having predetermined attributes defining the position and visible characteristics of the feature. Image data is derived from the model for each of an array of sampling points distributed across screen space. A non-homogeneous fog structure is defined in world space coordinates as a series of parallel strata of predetermined extinction coefficients. The positions of the eyepoint and a feature to be displayed relative to the fog structure are determined. The distance from the feature to the eyepoint is calculated. An average value of the extinction coefficients between the eyepoint and the feature is calculated from the defined parallel strata, and the attributes are modulated as a function of the calculated distance and the calculated average value of the extinction coefficients.
摘要:
A method for assembling a simulator in which a visual display system is arranged to display an image for viewing from a predetermined viewing position within a simulated viewing station. The visual display system and viewing station are mounted on a base. The viewing station is fabricated such that the location of the viewing position relative to the viewing station is established. The visual display system is fabricated so that when mounted in a predetermined position on the base the location of the viewing position relative to the base is established. When the viewing station and visual display system are mounted on the base, the visual display system is mounted in the predetermined position, and the viewing station being mounted at a position relative to the base selected such that the eye position of a person sat within the viewing station coincides with the location of the viewing position relative to the base.
摘要:
A method and apparatus for simulating the effect of non-homogeneous fog in an image displayed on a screen. The image is intended to represent the appearance of a model defined in a database in world space coordinates from an eyepoint position in world space, the model being defined in terms of individual features each having predetermined attributes defining the position and visible characteristics of the feature. Image data is derived from the model for each of an array of sampling points distributed across screen space. A non-homogeneous fog structure is defined in world space coordinates as a series of parallel strata of predetermined extinction coefficients. The positions of the eyepoint and a feature to be displayed relative to the fog structure are determined. The distance from the feature to the eyepoint is calculated. An average value of the extinction coefficients between the eyepoint and the feature is calculated from the defined parallel strata, and the attributes are modulated as a function of the calculated distance and the calculated average value of the extinction coefficients.
摘要:
A simulator for simulating radar or sonar signals returned to an observation point from a three-dimensional object of non-uniform reflectivity. An imaginary three-dimensional object is defined spatially in the form of a series of three-dimensional regularly shaped elements. Each element has allocated to it a predetermined level of uniform reflectivity.The position of boundaries of the element along an imaginary radial line extending from the observation point are calculated and the reflectivity allocated to points on the line on each side of each of the boundary positions is calculated. A sequence of signals is then generated which is representative of the allocated reflectivities occurring along the length of the line.
摘要:
A method and apparatus for simulating the illumination effects of a vehicle-mounted light source in an image displayed on a screen. The image is intended to represent the appearance of a model defined in a database in world space coordinates from and eyepoint position in world space, the model being defined in terms of a plurality of features each having predetermined attributes. The vehicle-mounted light source is defined in terms of an origin and a direction in eyepoint space. For each feature potentially contributing to the image, the angular position of a point on that feature relative to the light source is calculated as the angle between the light source direction and a line drawn to that point from the light source. An illumination intensity for that point is determined by reference to the calculated angle, and the illumination intensity is reduced as a function of the distance from the eyepoint to the said point to provide a resultant intensity. The attributes of the feature at the said point are modulated as a function of the resultant intensity.
摘要:
Elliptical features are described in an image generator database in terms of an origin and major and minor axes defined by reference to a world or model space coordinate system. Image data is assembled for display by transforming the database contents into screen space and assessing for each of an array of sampling points distributed across screen space which features are to contribute to the portion of a final image in which the sampling point is located. In the case of elliptical features, data is transformed into eyepoint space and each sampling point is projected into eyepoint space to determine the point of intersection between a line drawn through the sampling point from the eyepoint and a plane defined by the axes. The coordinates of the intersection point in a coordinate system defined by the origin and axes, are used to determine whether or not the feature contributes to the sampling point.