Patent ID: 7358971

Claim:
A computer graphics system for generating a pixel value for a pixel in an image, the pixel value being representative of a point in a scene as recorded on an image plane of a simulated camera, the computer graphics system being configured to generate the pixel value for an image using a selected ray-tracing methodology, the selected ray-tracing methodology making use of a ray tree, the ray tree having a ray shot from the pixel into a scene along a selected direction, at least some of the rays recursively splitting into a selected number of additional rays when the respective ray encounters a surface in the scene, each of the split rays being directed along a selected direction, though a selected number of tree levels, the computer graphics system comprising A. a low-discrepancy sequence generator configured to generate elements of at least one low-discrepancy sequence; B. an intersection indication generator configured to determine, for one of said rays in the ray tree, whether the one of the rays encounters a surface of an object in the scene; C. a ray generator configured to, when the intersection indication generator makes a positive determination in connection with the one of the rays, generate a selected number “M” of said additional rays each along a splitting direction determined by a respective direction value determined in accordance with ( y i , j ) j = 0 M - 1 = ( Φ b d ⁡ ( i ) ⊕ j m , … ⁢ , Φ b d + Δ ⁢ ⁢ d - 1 ⁡ ( i ) ⊕ Φ b d + Δ ⁢ ⁢ d - 2 ⁡ ( j ) ) where ⁢ ⁢ { Φ b d ⁡ ( i ) , … ⁢ , Φ b d + Δ ⁢ ⁢ d - 1 ⁡ ( i ) } ⁢ ⁢ and ⁢ ⁢ { j M , … ⁢ , Φ b d + Δ ⁢ ⁢ d - 2 ⁡ ( j ) } , are low-discrepancy sequences, for selected bases b and dimensions Δd, generated by the low-discrepancy sequence generator, where y i,j refers to a sample point, Φ b is an offset and where ⊕ represents addition modulo “one” and “i” and “j ”are selected integers identifying respective ray instances; and D. a function evaluator configured to generate at least one value representing an evaluation of a selected function using the rays associated with the ray tree, the value generated by the function evaluator corresponding to the pixel value.