Rolling Shutter Imager Global Shutter Effect via Illumination Timing

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Solution Overview

Problem

Electronic rolling shutter imagers in medical imaging systems suffer from rolling shutter effects, which cause image blur and other distortions due to the sequential exposure and readout of pixel rows.

Innovation Solution

The implementation of a global shutter effect in electronic rolling shutter imagers is achieved by coordinating illumination with the sensor's exposure and readout periods. This involves providing illumination during the period between resetting the last row of the sensor and reading out the first row, and extending the illumination period beyond the vertical blanking period to increase exposure time and sensitivity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If an electronic rolling shutter imager is used, then cost and performance advantages are achieved, but rolling shutter effects cause image blur and distortions

Engineering Contradiction:

Improvecost advantageVSAvoidimage quality

Core Design Contradiction:

Ease of manufactureVSManufacturing precision

Solution Approach 1:

The illumination is activated in advance during the vertical blanking period, before the rolling shutter readout begins. This preliminary illumination ensures that when the pixel rows are sequentially exposed during readout, the illumination is already in place, effectively creating a global shutter effect without requiring a mechanical shutter or global exposure mechanism.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The illumination continues throughout the entire rolling shutter readout process, from the moment the first row is read until the last row is read. This continuous illumination ensures that all pixel rows receive illumination during their respective exposure windows, eliminating the rolling shutter blur effect while maintaining the cost advantages of the electronic rolling shutter architecture.

Inventive Principle:

Principle #20Continuity of useful action

2Manufacturing precision

If illumination is provided during the vertical blanking period, then rolling shutter effects are reduced, but exposure time is limited

Engineering Contradiction:

Improveimage clarityVSAvoidexposure time

Core Design Contradiction:

Manufacturing precisionVSDuration of action of moving object

Solution Approach 1:

The illumination is extended to continue throughout the entire rolling shutter readout process, not just during the vertical blanking period. This ensures that all pixel rows receive illumination during their exposure windows, maximizing the effective exposure time while maintaining image clarity and eliminating rolling shutter effects.

Inventive Principle:

Principle #20Continuity of useful action

Solution Approach 2:

The illumination timing is dynamically adjusted to synchronize with the rolling shutter readout sequence. The illumination starts during the vertical blanking period and continues through the readout process, adapting to the dynamic timing requirements of the electronic rolling shutter to achieve optimal exposure for all rows.

Inventive Principle:

Principle #15Dynamics

3Measurement precision

If illumination period is extended beyond vertical blanking period, then exposure time and sensitivity are increased, but rolling shutter effects may reappear

Engineering Contradiction:

ImprovesensitivityVSAvoidimage quality

Core Design Contradiction:

Measurement precisionVSManufacturing precision

Solution Approach 1:

The illumination timing is precisely controlled and synchronized with the rolling shutter readout sequence. By using feedback from the readout timing signals, the illumination is activated during the vertical blanking period and continues through the readout process, ensuring that illumination is present for the entire exposure window of each row without introducing rolling shutter effects.

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The illumination is activated in advance during the vertical blanking period, before the rolling shutter readout begins. This preliminary action ensures that when the pixel rows are sequentially exposed during readout, the illumination is already in place, effectively creating a global shutter effect even with extended exposure time.

Inventive Principle:

Principle #10Preliminary action

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 approach eliminates rolling shutter effects, providing clear and sensitive images while maintaining the cost and performance advantages of rolling shutter imagers.

Implementation Method 1

each pixel builds an electric charge corresponding to the amount and wavelengths of light impinging the pixel

Methodology Applied

Scientific EffectPhotoelectric Effect: Photoelectric Effect

Data Source

PatentUS20250169688A1Systems and methods for medical imaging using a rolling shutter imager

Publication Date: 2025.05.29 STRYKER CORP

AI summary

A system includes an illumination source and an imaging apparatus that includes an electronic rolling shutter imager and is configured for sequentially resetting rows of pixels of the rolling shutter imager from a first row to a last row, sequentially reading charge accumulated at the rows of pixels from the first row to the last row, wherein the first row is read after resetting the last row, controlling the illumination source to illuminate the tissue of the subject with illumination light for an illumination period that lasts longer than a vertical blanking period, wherein the vertical blanking period is the period from the resetting of the last row to the reading of the first row, and generating an image frame from the readings of charge accumulated at the rows of pixels, wherein at least one reading of charge accumulated at a row of pixels is removed or replaced.