Adaptive Pixel Sampling for Rendering Latency Reduction

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Solution Overview

Problem

Uniformly sampling pixels in physically based rendering techniques, such as path-tracing, leads to inefficient use of processing resources and introduces latency due to redundant sampling, as not all pixels require the same number of samples to achieve convergence.

Innovation Solution

Adaptive sampling of pixels based on image data during ray tracing, where each pixel is sampled with a varying number of samples depending on the scene's texture and noise levels, with additional samples added only to pixels that do not meet a prescribed noise threshold until convergence is achieved.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If uniform sampling is applied to all pixels, then convergence of pixel values is achieved, but processing resources are wasted and latency increases due to redundant sampling

Engineering Contradiction:
Improveconvergence of pixel valuesVSAvoidrendering efficiency
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The patent applies different sampling strategies to different regions of the image based on local characteristics. Smooth regions are sampled with fewer samples while complex regions receive more samples, optimizing the balance between convergence quality and rendering efficiency.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The sampling rate is made dynamic rather than static. The system adaptively adjusts the number of samples per pixel based on measured noise levels and convergence criteria, allowing the rendering process to optimize resource allocation in real-time during the rendering pipeline.

Inventive Principle:
Principle #15Dynamics

2Measurement precision

If more samples are used per pixel, then rendering quality improves, but processing time and computational resources increase

Engineering Contradiction:
Improverendering qualityVSAvoidprocessing time
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The patent dynamically changes the sampling parameter (number of samples per pixel) based on local image characteristics and convergence metrics. By adjusting this parameter adaptively rather than using a fixed value, the system achieves high rendering quality in complex regions while minimizing processing time in smooth regions.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The system implements feedback mechanisms where noise measurements from preliminary sampling inform subsequent sampling decisions. Pixels that meet convergence criteria are terminated early, while those that don't receive additional samples, creating a closed-loop optimization system that balances quality and time.

Inventive Principle:
Principle #23Feedback

3Productivity

If adaptive sampling is implemented, then processing resources are optimized, but system complexity increases

Engineering Contradiction:
Improverendering efficiencyVSAvoidsampling system complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The rendering system is segmented into distinct functional modules: initial sampling stage, noise measurement stage, convergence evaluation stage, and adaptive resampling stage. This modular segmentation manages complexity by organizing the adaptive sampling process into manageable, independent components with clear interfaces.

Inventive Principle:
Principle #1Segmentation

Data Source

PatentUS11704861B2Adaptive sampling of pixels
Publication Date: 2023.07.18 OUTWARD INC
  • US11704861B2 patent drawing

AI summary

Adaptive sampling of pixels is disclosed. In some embodiments, convergence of pixels of a rendering is evaluated by removing texture from the rendering to eliminate non-convergence due to texture complexity and determining whether pixels values satisfy convergence criteria associated with pixel sampling. Those pixels of the rendering that have not converged are sampled with one or more additional samples. The completed rendering is output. Pixels of the completed rendering satisfy the convergence criteria and are not uniformly sampled.