Volume rendering method which increases apparent opacity of semitransparent objects in regions having higher specular reflectivity
AssigneeInternational Business Machines Corporation
InventorsAkio Doi, Koji Koyamada, Tatsuo Miyazawa
Life of this patent
Estimating the term…
Abstract
Portions showing greater specular reflection of an object to be displayed are displayed with pixels whose opacity, .alpha..sub.1, is emphasized according to the specular reflected component of a shading model, in which case the specular reflected component thus calculated for shading is also utilized for arithmetic operation of emphasized opacity, .alpha..sub.1, and high-speed processing is sought through tabulating various variables such as .alpha..sub.s (an additional opacity introduced for emphasis by a specular reflected component), .alpha..sub.n (a primary opacity), and G (a gradient vector).
Claims4
A volume rendering method for imaging a shaded three-dimensional object from volume data comprising the steps of:
- a. evaluating volume data representing a three-dimensional object at sampling points, including determining a value for the specular reflection component, if any, at the sampling points, the sampling points including a semi-transparent portion of the three-dimensional object;
- b. deducing a color-opacity volume at each sampling point, the color-opacity volume being determined from a color at the sampling point and an emphasized opacity at the sampling point, the emphasized opacity at the sampling point being an opacity value between the actual opacity value at the sampling point and an opacity value of one and being increased above the actual opacity value at the sampling point in dependence upon the value of the specular reflection component at the sampling point;
- c. determining a pixel color for each sampling point, the pixel color being determined from said color at the sampling point and a product of said emphasized opacities of said sampling points along a reference ray of light;
- and
- d. projecting the pixel colors onto a display screen to form an image of said three-dimensional object.
Dependencies are inferred from the claim text.