High performance shading of large volumetric data using screen-space partial derivatives
First Claim
Patent Images
1. A shading method for rendering volumetric data having a plurality of pixels, each of the plurality of pixels having a scalar value, comprising:
- direct rendering of the volumetric data, including the steps of;
determining a partial derivative with respect to the x direction of a first of the plurality of pixels in a screen-space;
determining a partial derivative with respect to the y direction of the first of the plurality of pixels in the screen-space;
determining a partial derivative with respect to a z direction of the first of the plurality of pixels in an object-space; and
determining a gradient based on the partial derivative with respect to the x direction, based on the partial derivative with respect to the y direction and based on the partial derivative with respect to the z direction.
6 Assignments
0 Petitions
Accused Products
Abstract
A method and system for shading large volumetric data sets using partial derivatives computed in screen-space. The method and system provide a fast and efficient shading a large datasets. Screen space derivatives are computed efficiently by evaluating neighboring pixel information together. The method can be efficiently implemented using GPUs (graphics processing units) that provides some access to information about neighboring pixels using ddx and ddy fragment processing functions.
60 Citations
22 Claims
-
1. A shading method for rendering volumetric data having a plurality of pixels, each of the plurality of pixels having a scalar value, comprising:
-
direct rendering of the volumetric data, including the steps of; determining a partial derivative with respect to the x direction of a first of the plurality of pixels in a screen-space; determining a partial derivative with respect to the y direction of the first of the plurality of pixels in the screen-space; determining a partial derivative with respect to a z direction of the first of the plurality of pixels in an object-space; and determining a gradient based on the partial derivative with respect to the x direction, based on the partial derivative with respect to the y direction and based on the partial derivative with respect to the z direction. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
-
-
12. A system of shading for rendering volumetric data, comprising:
-
a device for imaging a body part to derive scalar values associated with a plurality of pixels; a processor that, for each of the plurality of pixels, determines a partial derivative in an x direction in a screen-space, determines a partial derivative in a y direction in the screen-space, determines a partial derivative with respect to a z direction in an object-space and determines a gradient based in part on the partial derivative in the x direction, on the partial derivative in the y direction and on the partial derivative with respect to the z direction in the object-space; wherein the processor performs direct rendering of volumetric data based in part on the gradient; and a display that displays the rendered volumetric data. - View Dependent Claims (13, 14, 15, 16, 17, 18)
-
-
19. A method of rendering volumetric data having a plurality of pixels, comprising:
-
direct rendering of the volumetric data, including the steps of; obtaining a sample of data from a volume; classifying the sample; computing a gradient for each of the plurality of pixels, the gradient being based at least in part on a partial derivative with respect to an x direction in a screen space, on a partial derivative with respect to a y direction in the screen-space and on a partial derivative with respect to a z direction in an object-space; normalizing the gradient; computing diffuse and specular components; and computing output colors. - View Dependent Claims (20, 21)
-
-
22. A shading method for rendering volumetric data, the method comprising:
-
performing direct rendering including the steps of; selecting a first pixel in screen-space coordinates, the first pixel having a corresponding scalar value obtained from the volumetric data; determining a difference between the scalar value associated with the first pixel and a scalar value associated with a neighboring pixel in a x direction in screen space; determining a difference between the scalar value associated with the first pixel and a scalar value associated with a neighboring pixel in a y direction in screen space; determining a difference between the scalar value associated with the first pixel and a scalar value associated with a neighboring pixel in a z direction in object space; determining a gradient associated with the first pixel based on the differences; and using the gradient to compute a shading characteristic of the first pixel.
-
Specification