Bayer Color Filter Array Phase Alignment Detection

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Solution Overview

Problem

Current image sensors with color filter arrays face challenges in determining phase alignment, leading to potential color distortion due to misalignment, which requires manual input and calculation every time the sensor changes or cropping parameters are adjusted.

Innovation Solution

A method to automatically determine the phase alignment of a Bayer color filter array using spatial and spectral analysis, identifying quincunx and rectangular lattices within the array to accurately interpolate color components without manual specification.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If manual phase alignment specification is used, then color distortion can be avoided, but device complexity and operational burden increase

Engineering Contradiction:
Improvecolor accuracyVSAvoidalignment specification complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The system automatically determines CFA phase alignment by analyzing the input image data itself, eliminating the need for manual specification. The processor identifies phase alignment by examining patterns in the sensor array data and automatically configures demosaicking parameters, allowing the system to self-calibrate without user intervention.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The phase alignment determination is performed before the actual image processing begins. The system analyzes a portion of the input data to establish alignment parameters in advance, which then guide the subsequent demosaicking and color image generation processes, ensuring proper alignment is established beforehand.

Inventive Principle:
Principle #10Preliminary action

2Reliability

If phase alignment is recalculated every time sensor changes or cropping parameters are adjusted, then color accuracy is maintained, but processing time and computational load increase

Engineering Contradiction:
Improvecolor accuracyVSAvoidprocessing time
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The system performs phase alignment determination as a preliminary step before image processing, analyzing input data to establish alignment parameters in advance. This preliminary analysis enables the system to maintain color accuracy while reducing the need for repeated calculations during subsequent processing operations.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system uses the input image data as feedback to automatically determine and verify phase alignment. By analyzing patterns in the actual sensor data and comparing them against expected CFA patterns, the system can confirm alignment status and adjust processing parameters accordingly, maintaining accuracy without redundant calculations.

Inventive Principle:
Principle #23Feedback

3Ease of manufacture

If CFA is shifted to incorrect phase, then manufacturing tolerance is achieved, but image quality deteriorates due to color distortion

Engineering Contradiction:
ImproveCFA alignment toleranceVSAvoidimage quality
Core Design Contradiction:
Ease of manufactureVSManufacturing precision

Solution Approach 1:

The system analyzes input image data to detect the actual phase alignment state of the CFA and uses this feedback to automatically adjust processing parameters. By examining patterns in the sensor array and comparing them against expected distributions, the system can identify misalignment and compensate for it through automated parameter adjustment.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The system automatically modifies processing parameters based on detected phase alignment conditions. By changing demosaicking parameters and color space transformation settings according to the actual CFA phase, the system can compensate for manufacturing variations and maintain image quality despite tolerances in CFA placement.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentUS8441562B1Color filter array alignment detection
Publication Date: 2013.05.14 XILINX INC
  • US8441562B1 patent drawing
  • US8441562B1 patent drawing
  • US8441562B1 patent drawing

AI summary

In one embodiment of the present invention, a method for determining a phase alignment of a Bayer color filter array is provided. A quincunx lattice of the color filter array corresponding to a first color component is determined from an input frame of image data. Elements of the color filter array corresponding to first and second rectangular lattices of the color filter array are selected. Second and third color components corresponding to elements of the first and second rectangular lattices are determined from the sample values in an input frame of image data.