Rolling Shutter Sensor Driver for Structured Light Pattern Capture

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Solution Overview

Problem

Existing structured light 3D sensing systems using global shutter sensors are costly, and rolling shutter sensors, which start exposure for each pixel row at different times, struggle to capture clear structured light patterns due to hardware limitations and short projector on-time, resulting in incomplete or unclear patterns.

Innovation Solution

A driver mechanism for a rolling shutter sensor system that controls the exposure time of the RGB-IR rolling shutter image sensor and the structured light projector, ensuring the exposure time is longer than a predetermined value, using a control circuit to synchronize the sensor and projector operations, allowing for effective capture of structured light patterns.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a global shutter sensor is used to capture structured light pattern, then the structured light pattern can be captured clearly, but the system cost increases significantly

Engineering Contradiction:

Improvestructured light pattern clarityVSAvoidsystem cost

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The patent applies dynamics by making the exposure timing adaptive rather than fixed. The rolling shutter sensor dynamically adjusts its exposure window timing to coincide with the structured light projector activation, allowing clear pattern capture despite the sequential row-by-row scanning nature of rolling shutters

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The control circuit performs preliminary action by pre-synchronizing the exposure timing of the rolling shutter sensor with the structured light projector activation before actual capture begins. This ensures that when the projector turns on, the sensor is already positioned to capture the pattern clearly

Inventive Principle:

Principle #10Preliminary action

2Device complexity

If a rolling shutter sensor is used to reduce cost, then the system cost decreases, but the structured light pattern becomes incomplete or unclear

Engineering Contradiction:

Improvesystem costVSAvoidstructured light pattern clarity

Core Design Contradiction:

Device complexityVSMeasurement precision

Solution Approach 1:

The control circuit implements feedback by monitoring the rolling shutter sensor's row-by-row scanning progress and using this information to precisely time the structured light projector activation. This feedback mechanism ensures the pattern is projected during the correct exposure window, achieving clear capture with a cost-effective rolling shutter sensor

Inventive Principle:

Principle #23Feedback

3Adaptability or versatility

If the structured light projector turns on for a very short time due to hardware limitations, then the hardware requirements are met, but the structured light pattern is not clear enough

Engineering Contradiction:

Improvehardware compatibilityVSAvoidstructured light pattern clarity

Core Design Contradiction:

Adaptability or versatilityVSMeasurement precision

Solution Approach 1:

The patent applies parameter changes by precisely controlling the temporal parameters of both the sensor exposure and projector activation. By adjusting the exposure timing and duration parameters to match the projector's short on-time, the system achieves clear pattern capture within the hardware limitations

Inventive Principle:

Principle #35Parameter changes

Data Source

PatentUS11284022B2Driver mechanism for rolling shutter sensor to acquire structured light pattern

Publication Date: 2022.03.22 AMBARELLA INT LP

AI summary

An apparatus includes an RGB-IR rolling shutter image sensor, a structured light projector, and a control circuit. The control circuit may be configured to control an exposure time of the RGB-IR rolling shutter image sensor and a turn on time of the structured light projector to obtain a structured light pattern in images captured by the RGB-IR rolling shutter image sensor.