Image Sensor Light Calibration Compensation

Solution Overview

Problem

Existing optical scanners face challenges in effectively compensating for light variations from light sources and image sensor sensitivity, leading to faulty color balances and intensity issues in scanned images.

Innovation Solution

A method involving a first and second light calibration value recorded at opposite ends of an image sensor, with a compensation signal generated by processing these values to correct for spatial variations in light intensity, allowing for improved image quality by compensating for light source variations and image sensor sensitivity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If a single light calibration value is recorded at one position of the image sensor, then the compensation method is simple, but it cannot account for spatial variations in light intensity across the image sensor

Engineering Contradiction:

Improvecompensation method complexityVSAvoidlight intensity measurement accuracy

Core Design Contradiction:

Device complexityVSMeasurement precision

Solution Approach 1:

The image sensor is divided into multiple regions (first end and second end) with separate light calibration values recorded for each region. This segmentation allows the system to capture spatial variations in light intensity across different parts of the sensor, improving measurement precision without requiring an overly complex compensation method.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different light calibration values are recorded at different positions (first end and second end) of the image sensor to account for local variations in light intensity. This local quality approach ensures that each region is compensated based on its specific lighting conditions, improving overall measurement accuracy.

Inventive Principle:

Principle #3Local quality

2Measurement precision

If light calibration values are recorded at multiple positions of the image sensor, then spatial variations in light intensity are accounted for, but the compensation method becomes more complex

Engineering Contradiction:

Improvelight intensity measurement accuracyVSAvoidcompensation method complexity

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The image sensor is divided into multiple regions (first end and second end) with separate light calibration values recorded for each region. This segmentation allows the system to capture spatial variations in light intensity across different parts of the sensor, improving measurement precision without requiring an overly complex compensation method.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The system records light calibration values at multiple positions and uses these values to generate position-specific compensation signals. By changing the parameter of light intensity measurement across different spatial locations, the system accurately captures variations while maintaining a manageable compensation approach through linear interpolation.

Inventive Principle:

Principle #35Parameter changes

3Manufacturing precision

If compensation is applied for light source variations, then image intensity accuracy improves, but color balance may be affected due to unaccounted sensor sensitivity variations

Engineering Contradiction:

Improveimage intensity accuracyVSAvoidcolor balance accuracy

Core Design Contradiction:

Manufacturing precisionVSReliability

Solution Approach 1:

The system records light calibration values at multiple positions and uses these values to generate position-specific compensation signals. By changing the parameter of light intensity measurement across different spatial locations, the system accurately captures variations while maintaining a manageable compensation approach through linear interpolation.

Inventive Principle:

Principle #35Parameter changes

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This method enables line-by-line compensation for light variations, resulting in improved image quality by generating a compensation signal that adjusts for changes in light intensity and sensitivity, thereby reducing faults in color balance and intensity across scanned images.

Implementation Method 1

a first group of image sensor element(s) positioned in a first end of said first image sensor, recording a first light calibration value using said first group of image sensor element(s) indicative of a light intensity

Methodology Applied

Scientific EffectLight detection: Photoelectric Effect

Implementation Method 2

a second group of image sensor element(s) positioned in a second end of said first image sensor, thus resulting in a second light calibration value indicative of a light intensity

Methodology Applied

Scientific EffectLight detection: Photoelectric Effect

Data Source

PatentUS9118785B2Compensating for image sensor profile variations

Publication Date: 2015.08.25 CONTEX A S

AI summary

Disclosed is a method of scanning a physical medium by an image scanner comprising a first image sensor having a plurality of image sensor elements that provide an image, and a first light source associated with the first image sensor, the method comprising: guiding light from the first light source towards a first group of image sensor element(s); recording a first light calibration value using the first group of image sensor element(s). The method further comprises repeating the above step by using a second group of image sensor element(s) thus resulting in a second light calibration value; generating a first compensation signal for image sensor elements positioned between the first and the second group of image sensor element(s) by processing the first and the second light calibration value together; compensating said image signals provided by the first image sensor using the first compensation signal.