CMOS Rolling Shutter Imaging with Pulsed Light Control
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Solution Overview
Problem
Current CMOS imagers with rolling shutters struggle to capture sharp images of moving targets, especially in low light conditions, due to motion blur and high intensity light requirements, and require complex and costly global or mechanical shutters for high-speed imaging.
Innovation Solution
A data reader system that uses a CMOS imager with an electronic rolling shutter, where a processor dynamically controls integration times and light source pulsing based on ambient light intensity to capture stop-motion images, reducing motion blur and eliminating the need for complex shutters.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a CMOS imager with rolling shutter uses long integration time to capture images in low light conditions, then image brightness is improved, but motion blur increases
Solution Approach 1:
The patent applies periodic action by pulsing the light source at specific intervals during the rolling shutter exposure sequence. The light source is activated only during critical exposure windows for rows that need illumination, creating a periodic on-off pattern that provides necessary light without causing motion blur in the final image.
Solution Approach 2:
The system performs preliminary action by pre-determining which rows require illumination based on ambient light conditions before initiating the exposure sequence. The light source is pulsed in advance for specific rows during their integration period, ensuring those rows receive sufficient light while avoiding unnecessary illumination that would cause blur in other rows.
2Manufacturing precision
If a global shutter or mechanical shutter is used to capture sharp images of moving targets, then image sharpness is improved, but device complexity increases
Solution Approach 1:
The patent replaces the mechanical shutter system with an electronic control approach. Instead of using a mechanical shutter to simultaneously expose all pixels, the system uses a rolling shutter CMOS imager with electronic control over each row's integration time and a pulsed light source to achieve similar sharp image capture without mechanical moving parts.
Solution Approach 2:
The system applies dynamics by making the integration time and illumination timing adjustable and adaptive for each row based on ambient light conditions. The rolling shutter enables dynamic control where each row can have customized exposure parameters, allowing the system to adapt to varying lighting conditions while maintaining image sharpness.
3Manufacturing precision
If a rolling shutter CMOS imager uses short integration time to reduce motion blur, then image sharpness is improved, but light intensity requirement increases
Solution Approach 1:
The patent applies local quality by providing illumination only to specific rows that require it, rather than uniformly illuminating the entire sensor array. The pulsed light source is synchronized with the rolling shutter to activate only during the integration period of rows needing illumination, creating localized illumination events that reduce overall light intensity requirements while maintaining sharpness.
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
The system effectively captures sharp, decodable images of moving targets in various light conditions without the complexity and cost of global or mechanical shutters, ensuring efficient and reliable data reading.
Implementation Method 1
pixels that convert incident light energy into packets of electric charge
Data Source
Figure 1~1A
Figure 2~3
Figure 2A~3A
AI summary
A data reader preferably includes an imaging device that operates on a rolling reset basis to capture images of a moving target (540). Images of moving targets (540) are preferably analyzed to determine the ambient light intensity, and a processor (470) in the data reader preferably adjusts operation of the imager and of a light source (460) based on the intensity of the ambient light. Other data readers may use an imager with a mechanical shutter (1200) that is designed for rapid, frequent operation.