Polarizing Filter Image Sensor for Reflection Removal

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Solution Overview

Problem

Existing image pickup systems struggle to quickly capture images by removing unwanted reflected light components with desired sensitivity, as they require time to adjust exposure conditions, potentially missing the optimal capture timing.

Innovation Solution

An image pickup apparatus with a polarizing filter arranged in multiple directions, a first image sensor with polarizing filter elements, and a second image sensor without a polarizing filter, along with a polarization calculation unit and correction unit to detect and correct polarized light components, allowing for quick image capture by removing unwanted reflections.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a polarizing filter is rotated to capture images with different polarization directions, then polarization information can be obtained, but the capture time increases and timing may be missed

Engineering Contradiction:

Improvepolarization information accuracyVSAvoidimage capture time

Core Design Contradiction:

Measurement precisionVSLoss of time

Solution Approach 1:

The image sensor is divided into multiple regions, with each region equipped with polarizing filter elements having different polarization directions (e.g., 0°, 45°, 90°, 135°). This segmentation allows simultaneous capture of polarization information across different directions in a single shot, eliminating the need for sequential filter rotation while maintaining accurate polarization measurement capability

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent transitions from temporal dimension (rotating filter over time) to spatial dimension (arranging filters in different regions). By distributing polarizing filter elements with different orientations across spatial regions of the image sensor, the system captures all polarization directions simultaneously in one exposure, converting a time-based sequential process into a space-based parallel process

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

2Object-affected harmful factors

If a polarizing filter is used to remove reflected light, then unwanted reflections are reduced, but image sensitivity decreases

Engineering Contradiction:

Improvereflected light removalVSAvoidimage sensor sensitivity

Core Design Contradiction:

Object-affected harmful factorsVSUse of energy by moving object

Solution Approach 1:

Different regions of the image sensor are assigned different polarizing filter orientations based on local reflection characteristics. The correction unit selectively applies polarization-based reflection removal only to regions where it is beneficial, while preserving sensitivity in regions where reflections are not problematic. This localized approach maintains overall image quality while reducing unwanted reflections in specific areas

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent introduces a correction unit that acts as an intermediary between the raw sensor data and the final image output. This correction unit processes the captured images by selectively removing polarized reflected light components while preserving the underlying image information, thereby eliminating reflections without permanently degrading sensor sensitivity

Inventive Principle:

Principle #24Intermediary (Mediator)

3Reliability

If multiple images are captured while rotating a PL filter, then exposure conditions can be optimized, but the process becomes time-consuming

Engineering Contradiction:

Improveexposure condition accuracyVSAvoidimage capture speed

Core Design Contradiction:

ReliabilityVSProductivity

Solution Approach 1:

The patent enables continuous image capture without interruption for filter rotation. By having all polarization directions represented simultaneously in the image sensor regions, the system maintains continuous shooting capability, allowing the photographer to capture fast-moving subjects without missing the optimal moment due to filter adjustment delays

Inventive Principle:

Principle #20Continuity of useful 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

Enables rapid capture of images with unwanted reflections removed, maintaining image sensitivity and resolution without the need for manual filter adjustments, thus preventing timing misses during image capture.

Implementation Method 1

polarizing filter elements having different polarization directions

Methodology Applied

Scientific EffectPolarization: Polarisation

Data Source

PatentUS11569283B2Image pickup apparatus having image sensor equipped with polarizing element and control method therefor

Publication Date: 2023.01.31 CANON KK

AI summary

An image pickup apparatus that enables to quickly capture an image from which a predetermined reflected light component is removed with desired sensitivity. A polarizing filter two-dimensionally arranges a plurality of sets each of which includes polarizing filter elements having different polarization directions. A first image sensor has pixels that respectively correspond to polarizing filter elements of the polarizing filter. A polarization calculation unit detects a polarized component of light that enters into a region in which one set of polarizing filter elements are arranged based on signals output from pixels in the region of the first image sensor for each region. A correction unit corrects a pixel signal output from a pixel of a second image sensor corresponding to the region based on a calculation result by the polarization calculation unit for each pixel of the second image sensor.