Coded Aperture Mask for Visible and Near-Infrared Signal Separation

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Solution Overview

Problem

Existing image capturing devices face challenges in achieving high-resolution RGB and NIR image capture while maintaining compactness and cost-effectiveness, as they require multiple optical paths and specialized image sensors sensitive to near-infrared light.

Innovation Solution

An image capturing device that acquires image data with a periodic pattern of near-infrared light and processes it to separate visible light and near-infrared signals using Fourier transforms and filtering techniques, allowing for efficient image processing in both visible and near-infrared regions without the need for mechanical adjustments or specialized sensors.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Illumination intensity

If an IR cut filter is mechanically removed during highly sensitive image capturing, then sensitivity in dark places is improved, but device complexity increases and reliability decreases

Engineering Contradiction:

Improvesensitivity in dark placesVSAvoiddevice reliability

Core Design Contradiction:

Illumination intensityVSReliability

Solution Approach 1:

The patent replaces the mechanical removal of the IR cut filter with an optical encoding approach. A coded aperture mask with specific transmission patterns is placed in front of the image sensor, allowing near-infrared light to pass through in coded patterns while visible light is blocked. The captured images are then processed using decoding algorithms to separate and reconstruct the near-infrared signal, eliminating the need for mechanical filter removal while maintaining high sensitivity in dark conditions.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Measurement precision

If multiple optical paths and specialized image sensors are used for high-resolution RGB and NIR image capture, then image quality is improved, but device complexity and manufacturing cost increase

Engineering Contradiction:

Improveimage qualityVSAvoiddevice complexity

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The patent merges the functions of separate RGB and NIR imaging systems into a single integrated system. By using a coded aperture mask that simultaneously modulates both visible and near-infrared light paths, the device captures both types of information through one optical path and one image sensor. The subsequent image processing separates the signals computationally, achieving high-resolution RGB and NIR images without requiring multiple optical paths or specialized sensors.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The patent makes a standard image sensor multi-functional by using it to capture both visible light (for RGB images) and near-infrared light (for NIR images) through the coded aperture mask. The same optical path serves dual purposes, and the same sensor performs both visible and infrared detection, eliminating the need for specialized NIR-sensitive sensors and reducing overall device complexity.

Inventive Principle:

Principle #6Universality (Multi-functionality)

3Measurement precision

If an IR cut filter is always present in the optical system, then color reproduction is improved, but sensitivity in dark places deteriorates

Engineering Contradiction:

Improvecolor reproductionVSAvoidsensitivity in dark places

Core Design Contradiction:

Measurement precisionVSIllumination intensity

Solution Approach 1:

The patent implements periodic action through the coded aperture mask, which alternates between allowing near-infrared light to pass through and blocking it, while simultaneously capturing visible light information. The mask's transmission pattern changes spatially across different regions, creating a periodic modulation effect that encodes near-infrared information into the captured image. This periodic encoding allows the system to maintain accurate color reproduction when needed while capturing near-infrared signals for enhanced sensitivity in dark conditions.

Inventive Principle:

Principle #19Periodic 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 easy image processing in both visible and near-infrared regions using a general image capturing device configuration, reducing production costs and minimizing device failures, while effectively separating near-infrared light even under strong saturation conditions.

Implementation Method 1

A light incident on a camera is separated by such a three-color optical filter, and an image sensor converts the separated lights into image signals

Methodology Applied

Scientific EffectLight separation by wavelength: Dispersion (of waves)

Implementation Method 2

a Fourier transform unit which transforms the first color signals into a two-dimensional Fourier space

Methodology Applied

Scientific EffectFourier transform:

Implementation Method 3

an optical filter which separates an incident light into a plurality of colors

Methodology Applied

Scientific EffectOptical filtering: Filter (optical)

Data Source

PatentUS10334185B2Image capturing device, signal separation device, and image capturing method

Publication Date: 2019.06.25 NEC CORP

AI summary

Disclosed is a video capturing device which enables easy video processing in a visible light region and a near-infrared region while utilizing the configuration of a general video capturing device. This video capturing device is provided with a video data acquisition means for acquiring video data including a periodic pattern of near-infrared light, and a video processing means for acquiring a color signal of a visible light component and a near-infrared signal from the video data on the basis of the periodic pattern.