Analog Image Sensor Decimation Using Unequal Weighting
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Solution Overview
Problem
Existing image sensor systems that use Bayer filters face challenges in decimating images in the analog domain, leading to reduced image quality due to unevenly spaced effective sampling locations, which increases computational expense and power consumption when decimating in the digital domain.
Innovation Solution
The implementation of an apparatus and method that performs unequally-weighted-average even-factor decimation of photosite outputs in the analog domain using column connect switches, sampling switches, and mixing switches, with a controller providing control signals to achieve evenly spaced effective sampling locations, thereby reducing computational expense and power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If analog domain decimation is performed using conventional methods, then readout speed is improved, but image quality deteriorates due to unevenly spaced effective sampling locations
Solution Approach 1:
The patent changes the weighting parameters in the decimation process by applying unequally-weighted averaging instead of conventional equal-weighted averaging. This parameter change allows the system to maintain evenly spaced effective sampling locations while performing analog domain decimation, thereby preserving image quality while achieving fast readout speed.
Solution Approach 2:
The patent applies preliminary weighting adjustments to the photosite outputs before the averaging process. By pre-configuring the weights according to the unequally-weighted-average scheme, the system ensures that the final decimated output has evenly spaced effective sampling locations, thus maintaining image quality while enabling fast analog domain readout.
2Measurement precision
If digital domain decimation is performed to maintain image quality, then measurement precision is improved, but computational expense and power consumption increase
Solution Approach 1:
The patent replaces the digital domain decimation process with an analog domain implementation. By performing the decimation operation in the analog domain using voltage averaging circuits instead of digital computation, the system achieves the same image quality preservation without the high computational expense and power consumption associated with digital processing.
Solution Approach 2:
The patent implements the decimation parameter adjustments (unequally-weighted averaging) in the analog domain through circuit design rather than digital computation. This allows the system to maintain precise image quality control through analog voltage manipulation, significantly reducing power consumption compared to digital domain operations.
3Manufacturing precision
If digital domain decimation is performed to achieve evenly spaced sampling locations, then manufacturing precision of sampling grid is improved, but device complexity increases
Solution Approach 1:
The patent replaces complex digital computation algorithms with simple analog voltage averaging circuits. By implementing the decimation process in the analog domain, the system achieves uniformly spaced effective sampling locations through basic circuit operations rather than complex digital processing, thereby reducing device complexity while maintaining sampling grid precision.
Data Source
AI summary
Previously available analog domain decimation techniques are limited to simple equally-weighted averaging of photosite outputs. Decimation of a Bayer pattern image by an even-factor, such as by two or six, using simple equally-weighted averaging of photosite outputs in the analog domain results in effective sampling locations that are unevenly spaced apart. Standard interpolation of the unevenly spaced effective sampling locations generates image artifacts that reduce the quality of the reconstructed image in the smaller format because standard interpolation methods assume that the effective sampling locations are evenly spaced. Implementations of systems, methods and apparatus disclosed herein aim to produce substantially evenly spaced effective sampling locations in the analog domain. More specifically, in some implementations, the unequally-weighted-average even-factor decimation methods disclosed herein produce substantially more evenly spaced effective sampling locations as compared to the equally-weighted-average even-factor decimation processes previously used in the analog domain.