Indicia Reading Apparatus Rolling Shutter Exposure Control
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Solution Overview
Problem
Indicia reading apparatuses face challenges in achieving high-resolution image capture with low motion blur, particularly in applications requiring increased motion tolerance, due to limitations in exposure control and illumination management.
Innovation Solution
The apparatus employs an image sensor array with common exposure initiation times and sequential termination times for row exposure periods, coordinated with an illumination period that overlaps and terminates before or at the exposure termination time of each row, utilizing a low-cost high-resolution image sensor integrated circuit and an illumination assembly that projects a narrow wavelength band of light, reducing ambient light and motion artifacts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a conventional image sensor with simultaneous exposure for all rows is used, then the device complexity is low, but motion blur increases and image quality deteriorates
Solution Approach 1:
The patent divides the image sensor array into multiple rows, each with independent exposure control. This segmentation allows different rows to have different exposure termination times, enabling sequential readout while maintaining rolling shutter functionality, thus reducing motion blur without requiring complete redesign of the sensor architecture
Solution Approach 2:
The patent implements dynamic exposure control where the exposure termination time for each row is adjusted based on its position in the array. This dynamic timing control allows the system to optimize image quality for moving subjects by progressively terminating exposure across rows, effectively reducing motion blur artifacts
2Illumination intensity
If the illumination period is extended to cover the entire frame exposure period, then illumination intensity is sufficient for all pixels, but motion artifacts increase
Solution Approach 1:
The patent applies preliminary illumination by activating the light source before the exposure period begins and maintaining it through the entire exposure duration for each row. This ensures that when each row's exposure is terminated sequentially, the illuminating light is already present and continues to provide sufficient intensity without requiring extension beyond the actual exposure termination times
Solution Approach 2:
The patent provides localized illumination control where the illumination timing is precisely synchronized with each row's exposure period. The light source remains active during the entire frame exposure period, ensuring that each row receives adequate illumination exactly when needed, while avoiding unnecessary illumination after exposure termination that would create motion artifacts
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 results in improved image quality with reduced motion blur and increased motion tolerance, enabling efficient decoding of indicia in various applications.
Implementation Method 1
an image sensor array including a plurality of pixels arranged in a plurality of rows and columns of pixels
Implementation Method 2
an illumination assembly for projecting an illumination pattern during an illumination period, wherein the illumination period and the frame exposure period are coordinated so that at least a portion of the illumination period occurs during the frame exposure period
Data Source
AI summary
There is set forth herein an indicia reading apparatus having an image sensor array including a plurality of pixels arranged in a plurality of rows and columns of pixels. The image sensor array can include a frame exposure period in which a certain subsequent and further subsequent row exposure periods have common exposure initiation times and each group of rows has sequential exposure termination times. An indicia reading apparatus can be controlled so that a light source bank of an illumination pattern assembly for projecting an illumination pattern is energized during an illumination period that overlaps a frame exposure period. The apparatus can be further controlled so that an illumination period terminates at or prior to an exposure termination time of the certain row.