Solid-State Image Sensor A/D Correction for Converter Linearity

Solution Overview

Problem

Solid-state imaging devices face challenges in achieving linear input/output characteristics due to the nonlinear nature of time analog-to-digital converter type A/D converters, which affects the accuracy of pixel signal conversion and requires correction methods to improve signal-to-noise ratio and reduce power consumption.

Innovation Solution

The implementation of a solid-state imaging device with multiple A/D converters and correction units that produce and update correction formulas based on reference voltages and coefficient changes, ensuring linearity correction of digital signals and reducing the need for frequent recalibration of all converters.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If correction formulas are frequently updated for all A/D converters, then linearity correction precision is improved, but power consumption increases and processing time increases

Engineering Contradiction:

Improvelinearity correction precisionVSAvoidpower consumption

Core Design Contradiction:

Measurement precisionVSUse of energy by moving object

Solution Approach 1:

The determination unit automatically monitors coefficient changes and decides when correction formula updates are necessary, eliminating the need for external control or frequent manual recalibration. The system serves itself by detecting when environmental changes actually affect performance and only then triggering the update process.

Inventive Principle:

Principle #25Self-service

Solution Approach 2:

The system monitors changes in correction coefficients as indicators of environmental drift. By tracking parameter changes (coefficient variations) rather than continuously updating all correction formulas, the system efficiently determines when recalibration is actually needed, reducing unnecessary power consumption while maintaining accuracy.

Inventive Principle:

Principle #35Parameter changes

2Measurement precision

If correction formulas are frequently updated for all A/D converters, then linearity correction precision is improved, but processing time increases

Engineering Contradiction:

Improvelinearity correction precisionVSAvoidprocessing time

Core Design Contradiction:

Measurement precisionVSLoss of time

Solution Approach 1:

The determination unit automatically monitors coefficient changes and decides when correction formula updates are necessary, eliminating the need for external control or frequent manual recalibration. The system serves itself by detecting when environmental changes actually affect performance and only then triggering the update process.

Inventive Principle:

Principle #25Self-service

Solution Approach 2:

The system monitors changes in correction coefficients as indicators of environmental drift. By tracking parameter changes (coefficient variations) rather than continuously updating all correction formulas, the system efficiently determines when recalibration is actually needed, reducing unnecessary processing time while maintaining accuracy.

Inventive Principle:

Principle #35Parameter changes

3Measurement precision

If multiple A/D converters are used with individual correction, then conversion accuracy is improved, but device complexity increases

Engineering Contradiction:

Improveconversion accuracyVSAvoiddevice complexity

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

A single determination unit serves all first A/D converters by monitoring correction coefficients from any of them and deciding when updates are needed. This multi-functional approach allows one unit to manage the correction needs of multiple converters, reducing overall system complexity while maintaining individual converter accuracy.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The determination unit receives feedback in the form of correction coefficients from second A/D converters and uses this information to decide when first A/D converters need updating. This feedback mechanism creates an efficient control system that coordinates multiple converters without requiring complex independent control for each one.

Inventive Principle:

Principle #23Feedback

Data Source

PatentUS8743248B2Solid-state imaging device, method of driving solid-state imaging device, and image processing device

Publication Date: 2014.06.03 OLYMPUS CORPORATION(JP)

AI summary

An image processing device comprising: first A/D converters that receive output signals of respective columns of a plurality of pixels arranged in a matrix form, convert the output signals into first digital signals, and output the first digital signals; a second A/D converter that receives a correction signal, converts the correction signal into a second digital signal, and outputs the second digital signal; a first correction calculation unit that produces a first correction formula; a second correction calculation unit that produces a second correction formula based on the second digital signal; a determination unit that compares a coefficient of the second correction formula and a coefficient of a second correction formula produced before the second correction formula, and determines whether or not to produce the first correction formula based on the comparison result; and a signal output unit that outputs an update signal when it is determined to produce the first correction formula.