Digital Image Sensor Intensity Uniformity Compensation

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Solution Overview

Problem

Conventional CMOS image sensors often produce non-uniform images due to angular dependency in pixel layout, leading to intensity variations despite healthy pixels, which is difficult to address through lengthy and expensive design processes.

Innovation Solution

A digital processing method that captures images of a white light source to calculate compensation factors for each pixel, storing these factors for enhancing intensity uniformity in actual images by adjusting signal intensities.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If pixel layout is designed to minimize angular dependency, then image uniformity is improved, but development time and cost increase

Engineering Contradiction:

Improveimage uniformityVSAvoiddevelopment time

Core Design Contradiction:

Manufacturing precisionVSLoss of time

Solution Approach 1:

The patent applies preliminary action by capturing a reference image of a uniform light source before actual imaging, calculating compensation factors for each pixel based on intensity variations, and storing these factors for subsequent use. This pre-computation approach allows the system to address angular dependency issues without requiring time-consuming redesign of pixel layouts, thereby improving image uniformity while avoiding extended development cycles.

Inventive Principle:

Principle #10Preliminary action

2Manufacturing precision

If pixel layout is designed to minimize angular dependency, then image uniformity is improved, but manufacturing cost increases

Engineering Contradiction:

Improveimage uniformityVSAvoidmanufacturing cost

Core Design Contradiction:

Manufacturing precisionVSEase of manufacture

Solution Approach 1:

The patent applies parameter changes by introducing compensation factors that modify the output signal intensity of each pixel based on its angular dependency characteristics. Instead of changing the physical pixel layout parameters, the system dynamically adjusts the electrical signal parameters through multiplication with compensation factors, thereby improving image uniformity without incurring additional manufacturing costs for redesigning sensor structures.

Inventive Principle:

Principle #35Parameter changes

3Adaptability or versatility

If pixels collect optical signals at different ray acceptance angles, then imaging capability is enhanced, but intensity uniformity deteriorates

Engineering Contradiction:

Improveimaging capabilityVSAvoidintensity uniformity

Core Design Contradiction:

Adaptability or versatilityVSManufacturing precision

Solution Approach 1:

The patent applies feedback by using the captured reference image of a uniform light source to calculate compensation factors that reflect the actual angular dependency characteristics of each pixel. These compensation factors are then applied to subsequent images to correct intensity variations. This feedback mechanism allows the system to maintain enhanced imaging capability from varied ray acceptance angles while compensating for the resulting intensity non-uniformity.

Inventive Principle:

Principle #23Feedback

Data Source

PatentUS7450161B1System and method to enhance the uniformity of intensity distribution on digital imaging sensors

Publication Date: 2008.11.11 INTELLECTUAL VENTURES II LLC

AI summary

Systems, computer readable media and methods for digital processing of images captured by a sensor to enhance intensity uniformity of the images. The sensor captures an image of a white light source. Then, using the captured image, a compensation factor for each pixel of the image sensor is calculated and stored in a memory. Next, an actual image is captured by the image sensor. Subsequently, the signal intensity of each pixel is modified using the corresponding compensation factor to enhance the uniformity of the actual image.