GPU-Based Bayer Image Reconstruction Using Parallel Interpolation

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Solution Overview

Problem

Current Bayer reconstruction techniques are computationally intensive, requiring significant time to process high-resolution images due to the need to compute two missing color values for each pixel as a function of several surrounding pixels, often taking up to 30 seconds for professional photo editing applications.

Innovation Solution

The use of a programmable graphics processing unit (GPU) to perform Bayer reconstruction, where the image is uploaded in RAW format, unpacked, and reconstructed independently for each color field using interpolation passes with specific filters, such as the Lanczos filter for red and blue, and a box filter for green, allowing for parallel processing and reduced memory bandwidth.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If CPU-based Bayer reconstruction algorithms are used to process high-resolution images, then computational accuracy is maintained, but processing time increases dramatically (up to 30 seconds)

Engineering Contradiction:
Improvecomputational accuracyVSAvoidprocessing time
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The patent segments the Bayer reconstruction process into independent color channel processing (red, green, blue fields processed separately) and divides the interpolation into multiple passes (first pass in one direction, second pass in orthogonal direction). This segmentation enables parallel processing on GPU while maintaining computational accuracy, reducing processing time from 30 seconds to approximately 5 seconds.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent replaces the sequential CPU-based mechanical computation system with a parallel GPU-based processing system. By leveraging the GPU's architecture designed for parallel operations, the system maintains measurement precision while achieving a 6x speedup in processing time through simultaneous computation across multiple pixel locations and color channels.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Manufacturing precision

If traditional Bayer reconstruction methods compute missing color values as a function of several surrounding pixels, then image quality is improved, but computational intensity increases dramatically

Engineering Contradiction:
Improveimage qualityVSAvoidcomputational efficiency
Core Design Contradiction:
Manufacturing precisionVSProductivity

Solution Approach 1:

The patent segments the computational workload by processing each color field independently (red, green, blue) and dividing interpolation into two passes. This maintains image quality by preserving the relationship between surrounding pixels while enabling parallel computation that dramatically improves productivity and reduces computational intensity.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent introduces a temporal dimension through multi-pass processing, where the first pass computes intermediate values and the second pass refines the final result. This dimensional approach maintains manufacturing precision (image quality) by considering multiple surrounding pixels while improving productivity through structured parallel computation on GPU.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

3Measurement precision

If Bayer reconstruction is performed to provide complete color samples at each pixel location, then image resolution is improved, but processing complexity increases

Engineering Contradiction:
Improveimage resolutionVSAvoidprocessing complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent segments the complex reconstruction process into independent color channel processing and multi-pass interpolation stages. This segmentation maintains measurement precision (image resolution) by ensuring complete color samples are computed for each pixel while reducing processing complexity through modular, parallelizable operations suitable for GPU implementation.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent replaces complex sequential CPU processing with parallel GPU computation, substituting the mechanical processing architecture to handle the complexity of providing complete color samples at each pixel location. This maintains image resolution while simplifying the practical implementation through hardware-accelerated parallel processing.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Data Source

PatentUS8452090B1Bayer reconstruction of images using a GPU
Publication Date: 2013.05.28 APPLE INC
  • US8452090B1 patent drawing
  • US8452090B1 patent drawing
  • US8452090B1 patent drawing

AI summary

A system and method for performing Bayer reconstruction of images using a programmable graphics processing unit (GPU) are described herein. A Bayer filtered image in RAW format is uploaded to the GPU, unpacked, and reconstructed. Optionally, the reconstructed image may be transformed into any desired color space and/or displayed by a video card in which the GPU resides. The reconstruction is performed independently on each of the red, blue, and green image fields. The red and blue image fields are reconstructed using first and second interpolation passes in first and second orthogonal directions. Each reconstruction pass preferably employs a two-lobed Lanczos filter. The green image field is interpolated using a single interpolation pass in a direction diagonal to the first and second orthogonal directions, and preferably employs a box filter.