Machine-Learned Guide Channels for 3D Scene Denoising
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Solution Overview
Problem
Path-tracing for rendering 3-D scenes is computationally expensive due to the need for a large number of samples to reduce noise, making it impractical for devices with limited resources, and existing denoising algorithms do not efficiently improve quality without significant computational overhead.
Innovation Solution
A method involving machine learning models to derive enhanced guide channels from initial guide channels and noisy images, using local affine models to approximate and denoise the image, allowing for efficient denoising and rendering on devices with limited resources.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the number of samples per pixel is increased to reduce noise, then the quality of the path-traced image is improved, but the computational cost increases significantly
Solution Approach 1:
The patent introduces guide channels as intermediary data structures that capture scene geometry and lighting information. These guide channels serve as mediators between the noisy path-traced image and the denoised output, enabling noise reduction without requiring additional light transport samples. The guide channels contain pre-computed information about surfaces, lights, and shadows that guide the denoising process.
Solution Approach 2:
The patent replaces the mechanical approach of increasing sample counts with a computational model-based approach using guided filtering. Instead of mechanically adding more samples to reduce noise, the system uses a learned denoising model that operates on guide channels and the noisy image, substituting brute-force sampling with intelligent signal processing.
2Measurement precision
If denoising algorithms are applied to reduce noise, then the image quality is improved, but the computational overhead increases
Solution Approach 1:
The patent segments the denoising problem into multiple independent guide channels (e.g., depth, surface normals, shadow maps, lighting information) that can be processed separately. Each guide channel captures specific aspects of the scene, and the denoising model processes these segmented channels independently before combining them to produce the final denoised image.
Solution Approach 2:
The patent performs preliminary computation of guide channels during the rendering process itself, before denoising is applied. These guide channels are pre-computed with scene geometry and lighting information, so that when denoising occurs, the heavy lifting of scene analysis has already been done, reducing the computational overhead of the actual denoising operation.
3Manufacturing precision
If more samples are used to achieve better light transport approximation, then the accuracy is improved, but the processing time increases
Solution Approach 1:
The patent changes the parameters of the rendering pipeline by computing multiple guide channels with different characteristics (depth, normals, shadows, lighting) at controlled sample counts. Instead of uniformly increasing samples across all computations, the system adjusts sampling strategies for different guide channel types, optimizing the balance between accuracy and processing time.
Data Source
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Figure 3A~3B
AI summary
A method of rendering an image of a 3-D scene is provided. The method comprises: rendering (110) a noisy image at a first resolution; obtaining (112) one or more initial guide channels at the first resolution, and obtaining (140) one or more corresponding initial guide channels at a second resolution. The second resolution may be the same resolution as, or a higher resolution than, the first resolution. When the two resolutions are the same, the one or more initial guide channels at the first resolution and the one or more corresponding initial guide channels at the second resolution may be provided by a single set of initial guide channels. Enhanced guide channels are derived from the initial guide channels and the noisy image, using one or more machine learning models. For each of a plurality of local neighbourhoods, the method comprises: calculating (120) the parameters of a denoising model that approximates the noisy image (in the local neighbourhood) as a function of the one or more enhanced guide channels (at the first resolution), and applying (130, 150) the calculated parameters to the one or more enhanced guide channels (at the second resolution), to produce a denoised image at the second resolution. To be accompanied, when published, by Figure 1 of the accompanying drawings.