Imaging Sensor Dual-Mode Motion Detection for Low-Power Monitoring

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Solution Overview

Problem

CMOS image sensors in security cameras consume excessive power due to A/D conversion, data transfer, and image processing, which is inefficient for detecting intrusions.

Innovation Solution

An imaging device with a dual-mode operation: a first mode for minimal analog processing to generate a trigger signal and a second mode for detailed digital processing, reducing power consumption by minimizing digital processing until necessary.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If A/D conversion and digital image processing are continuously performed, then detection accuracy is improved, but power consumption increases

Engineering Contradiction:

Improvedetection accuracyVSAvoidpower consumption

Core Design Contradiction:

Measurement precisionVSUse of energy by moving object

Solution Approach 1:

The imaging device dynamically switches between two operational modes: a first mode performing minimal analog processing for low power consumption, and a second mode performing full digital processing for high detection accuracy. The mode is determined based on whether a trigger signal is generated, allowing the system to adapt its processing intensity to actual needs.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

Instead of continuously performing full digital processing, the system performs only partial processing (analog difference calculation) during normal operation and activates full digital processing only when necessary (when trigger signal exceeds threshold), thus avoiding excessive action while maintaining detection capability.

Inventive Principle:

Principle #16Partial or excessive action

2Use of energy by moving object

If minimal analog processing is performed, then power consumption is reduced, but detection capability is limited

Engineering Contradiction:

Improvepower consumptionVSAvoiddetection capability

Core Design Contradiction:

Use of energy by moving objectVSReliability

Solution Approach 1:

The system dynamically adjusts its detection capability by switching between analog-only processing (first mode) and hybrid analog-digital processing (second mode). When motion is detected via analog difference calculation, the system transitions to the second mode, activating full digital processing to ensure reliable detection and recording of the event.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The analog processing circuit continuously performs preliminary difference calculation between current and reference imaging data to detect motion. This preliminary action enables early warning detection, allowing the system to prepare for and respond to intrusion events before full digital processing is activated.

Inventive Principle:

Principle #10Preliminary action

3Reliability

If continuous digital processing is performed, then intrusion detection reliability is improved, but power consumption increases

Engineering Contradiction:

Improveintrusion detection reliabilityVSAvoidpower consumption

Core Design Contradiction:

ReliabilityVSUse of energy by moving object

Solution Approach 1:

The imaging device dynamically switches between operational modes based on detected motion. During normal conditions, it operates in the first mode with minimal processing. When the analog processing circuit generates a trigger signal indicating motion, it switches to the second mode for reliable digital processing and recording, thus maintaining detection reliability only when needed.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The system uses periodic analog difference calculation to monitor for motion events. Full digital processing is activated periodically only when triggered by motion detection, rather than continuously, thereby reducing overall power consumption while maintaining detection reliability during critical events.

Inventive Principle:

Principle #19Periodic 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

Reduces power consumption by performing only minimal analog processing for trigger signal generation and detailed digital processing when needed, while maintaining effective intrusion detection.

Implementation Method 1

a pixel portion including a plurality of pixels each including a photoelectric conversion element

Methodology Applied

Scientific EffectPhotoelectric conversion: Photoelectric Effect

Data Source

PatentUS12511982B2Imaging device, monitoring device, and electronic appliance

Publication Date: 2025.12.30 SEMICON ENERGY LAB CO LTD

AI summary

An imaging device capable of detecting differences with low power consumption is provided. The imaging device includes a pixel including a photoelectric conversion element and a transistor; an analog processing circuit; and a digital processing circuit. The imaging device is operated in a first mode and a second mode. In the first mode, the analog processing circuit detects a difference between first imaging data taken by the pixel and second imaging data taken by the pixel and generates a trigger signal on the basis of the value of the difference. In the second mode, the digital processing circuit converts third imaging data taken by the pixel into digital data. Switching from the first mode to the second mode is performed on the basis of the trigger signal.