Nvidia Corporation

Pawel Kozlowski

Alexey Panteleev

Maksim Aizenshtein

Tim Cheblokov

In examples, a filter used to denoise shadows for a pixel(s) may be adapted based at least on variance in temporally accumulated ray-traced samples. A range of filter values for a spatiotemporal filter may be defined based on the variance and used to exclude temporal ray-traced samples that are outside of the range. Data used to compute a first moment of a distribution used to compute variance may be used to compute a second moment of the distribution. For binary signals, such as visibility, the first moment (e.g., accumulated mean) may be equivalent to a second moment (e.g., the mean squared). In further respects, spatial filtering of a pixel(s) may be skipped based on comparing the mean of variance of the pixel(s) to one or more thresholds and based on the accumulated number of values for the pixel.

Spatiotemporal self-guided shadow denoising in ray-tracing applications

Systems and methods for improving quality of rendered images. Temporal accumulation using jittered motion vectors may be performed in intermediate passes.

System and method for image generation using jittered motion vectors

Systems and methods relate to the determination of accurate motion vectors, for rendering situations such as a noisy Monte Carlo integration where image object surfaces are at least partially translucent. To optimize the search for 'real world' positions, this invention defines the background as first path vertices visible through multiple layers of refractive interfaces. To find matching world positions, the background is treated as a single layer morphing in a chaotic way, permitting the optimized algorithm to be executed only once. Further improving performance over the prior linear gradient descent, the present techniques can apply a cross function and numerical optimization, such as Newton's quadratic target or other convergence function, to locate pixels via a vector angle minimization. Determined motion vectors can then serve as input for services including image denoising.

Motion vector optimization for multiple refractive and reflective interfaces

Approaches presented herein can reduce temporal lag that may be introduced in a generated image sequence that utilizes temporal accumulation for denoising in dynamic scenes. A fast historical frame can be generated along with a full historical frame generated for a denoising process, with the fast historical frame being accumulated using an exponential moving average with a significantly higher blend weight. This fast history frame can be used to determine a clamping window that can be used to clamp a corresponding full historical value before, or after, reprojection. The fast historical blend weight can be adjusted to control the amount of noise versus temporal lag in an image sequence. In some embodiments, differences between fast and full historical values can also be used to determine an amount of spatial filtering to be applied.

History clamping for denoising dynamic ray-traced scenes using temporal accumulation

Apparatuses, systems, and techniques are presented to reduce temporal lag when a dynamic event is occurring in computer generated video. In one embodiment, a first averaging algorithm is utilized to determine a display value for a pixel based at least in part on previous pixel values. Once a dynamic event is detected, a set of the previous pixel values is averaged using a second averaging algorithm. The pixel value is updated based on the first averaging of the pixel values and the second averaging of the pixel values to determine a current pixel value.

Temporal denoiser quality in dynamic scenes

In examples, threads of a schedulable unit (e.g., a warp or wavefront) of a parallel processor may be used to sample visibility of pixels with respect to one or more light sources. The threads may receive the results of the sampling performed by other threads in the schedulable unit to compute a value that indicates whether a region corresponds to a penumbra (e.g., using a wave intrinsic function). Each thread may correspond to a respective pixel and the region may correspond to the pixels of the schedulable unit. A frame may be divided into the regions with each region corresponding to a respective schedulable unit. In denoising ray-traced shadow information, the values for the regions may be used to avoid applying a denoising filter to pixels of regions that are outside of a penumbra while applying the denoising filter to pixels of regions that are within a penumbra.

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Truckee, CA, United States of America

Pawel Kozlowski