Imaging Device Polarization Alignment Wave Plate
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Solution Overview
Problem
Existing imaging devices that generate images based on light with different polarization directions without alignment face issues such as differences in appearance, incorrect spectral reflectance calculation, and erroneous parallax detection, particularly for glossy objects, due to the limitations in aligning polarization directions and maintaining uniform light intensity.
Innovation Solution
An imaging device comprising a pupil region with multiple regions, polarizers to align and convert light polarization, and an imaging element with pixel units receiving light in different polarization directions, along with a wave plate to convert linearly polarized light into circularly or elliptically polarized light, allowing for flexible polarization direction design and uniform light intensity across images.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If light in two different polarization directions is received by different pixels without aligning polarization directions, then two independent images can be acquired, but differences in image appearance and uniformity occur due to varying light intensity and polarization alignment issues
Solution Approach 1:
A first polarizer is introduced to preliminarily align the polarization direction of incident light before it reaches the pixel array. This preliminary alignment ensures that subsequent polarization-based image separation occurs from a unified polarization reference, eliminating appearance differences between images while maintaining the capability to acquire multiple independent images simultaneously
Solution Approach 2:
A wave plate is positioned between the first polarizer and the pixel array to act as an intermediary that converts the uniformly polarized light into light with varying polarization directions for different spatial regions. This mediator enables the pixel array to receive light in different polarization directions while maintaining uniform light intensity and appearance across all acquired images
2Measurement precision
If a polarization filter is used to shield s-polarized light for capturing water surface images, then one polarization direction can be aligned, but it is difficult to align the other polarization direction properly
Solution Approach 1:
The pupil region of the imaging optical system is divided into multiple regions, with each region assigned to receive light in a specific polarization direction. This segmentation allows different polarization directions to be captured simultaneously by different pixel groups, providing both precise alignment for specific applications and flexibility for multiple polarization directions
Solution Approach 2:
The wave plate enables dynamic control over the polarization directions received by different pixel units. By adjusting the wave plate's orientation or type, the system can adaptively configure which polarization directions are captured by which pixels, providing versatility for different imaging scenarios while maintaining precise alignment
3Ease of operation
If linearly polarized light is aligned in one direction and then images are generated, then polarization direction can be controlled, but the amount of light transmitted varies and uniformity cannot be maintained
Solution Approach 1:
Different regions of the pupil are assigned to receive light with different polarization directions, allowing each region to be optimized for its specific polarization requirement. The wave plate creates local variations in polarization direction across the pupil region, enabling controlled polarization direction for each local area while maintaining overall light intensity uniformity through the systematic arrangement
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 solution effectively suppresses differences in image appearance caused by polarization direction variations, enables flexible design of polarization directions, and ensures uniform light intensity across images, improving image quality and accuracy, especially for glossy objects.
Implementation Method 1
a wave plate that converts linearly polarized light aligned in the first polarization direction by the first polarizer into circularly or elliptically polarized light
Implementation Method 2
a first polarizer that aligns a polarization direction of light transmitted through the first pupil region and the second pupil region with a first polarization direction
Data Source
AI summary
Provided are an imaging device and an imaging method that can suppress a difference in appearance caused by a difference between the polarization directions of received light in a case in which different images are generated on the basis of light having different polarization directions, have flexibility in the design of the polarization direction of light forming different images, and can generate a plurality of images having a uniform amount of light. An imaging device (1) includes: an imaging optical system (10); a first polarizer that aligns a polarization direction of light transmitted through a first pupil region (E1) and a second pupil region (E2); a wave plate (14) that converts the light into circularly or elliptically polarized light; a second polarizer that transmits light in a second polarization direction different from the first polarization direction; a third polarizer that transmits light in a third polarization direction different from the first polarization direction and the second polarization direction; an imaging element (100) that has a plurality of pixel units receiving the light transmitted through the first pupil region and the second pupil region; and an image generation unit.