Camera Module Depth Extraction via IR Filter Tilt

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Solution Overview

Problem

Current time-of-flight (ToF) methods for extracting depth information have low resolution, which cannot be significantly improved without increasing the volume and manufacturing costs of camera modules.

Innovation Solution

A camera module with a tilting unit that adjusts the optical path of the infrared filter, using Hall sensors to detect tilt information and an image control unit to calculate and correct depth information, allowing for subpixel shifting and super-resolution depth information extraction without increasing the number of pixels in the image sensor.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If the number of pixels of the image sensor is increased to increase resolution, then the resolution of depth information is improved, but the volume and manufacturing costs of the camera module greatly increase

Engineering Contradiction:
Improveresolution of depth informationVSAvoidvolume of camera module
Core Design Contradiction:
Measurement precisionVSVolume of stationary object

Solution Approach 1:

The patent introduces a temporal dimension by capturing multiple images at different time points (first image at time t1, second image at time t2) and uses optical path shifting through the tilting unit to create spatial variations. This allows high-resolution depth information to be reconstructed from multiple lower-resolution images without increasing the physical pixel count of the sensor, thereby resolving the contradiction between resolution and module volume.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The patent employs a tilting unit that dynamically adjusts the optical path between the lens unit and image sensor during the imaging process. By tilting the optical path at different angles for different time points, the system creates varied spatial sampling patterns that enable super-resolution reconstruction without requiring a higher pixel-count sensor, thus maintaining compact module volume while achieving high resolution.

Inventive Principle:
Principle #15Dynamics

2Measurement precision

If the number of pixels of the image sensor is increased to increase resolution, then the resolution of depth information is improved, but the manufacturing costs of the camera module greatly increase

Engineering Contradiction:
Improveresolution of depth informationVSAvoidmanufacturing costs of camera module
Core Design Contradiction:
Measurement precisionVSEase of manufacture

Solution Approach 1:

The patent transitions from a static spatial sampling approach to a dynamic temporal-spatial approach. By capturing images at multiple time points and utilizing optical path shifting, the system reconstructs high-resolution depth information algorithmically rather than through hardware pixel multiplication. This significantly reduces manufacturing costs as the image sensor pixel count remains unchanged while achieving superior resolution.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The patent changes the parameters of the optical path (tilt angle, optical path length) dynamically during the imaging process rather than increasing the fixed parameter of pixel count. This parameter change approach allows the system to achieve high resolution through temporal and spatial modulation of the optical path, avoiding the high manufacturing costs associated with high-pixel-count sensors.

Inventive Principle:
Principle #35Parameter changes

3Measurement precision

If a tilting unit is added to shift the optical path, then high-resolution depth information can be obtained without increasing pixel count, but the device complexity increases

Engineering Contradiction:
Improveresolution of depth informationVSAvoidcomplexity of camera module structure
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The tilting unit in the patent serves multiple functions: it shifts the optical path to create spatial variations for super-resolution reconstruction, and it also enables temporal-spatial sampling diversity. By integrating this single component to perform multiple roles, the patent achieves high-resolution depth information without proportionally increasing device complexity, as the tilting unit replaces what would otherwise require multiple sensors or complex mechanical systems.

Inventive Principle:
Principle #6Universality (Multi-functionality)

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 high-resolution depth information extraction with a simple structure, achieving subpixel shift detection and super-resolution without increasing the number of pixels, thus reducing costs and module size.

Implementation Method 1

The detection unit may include a first Hall sensor and a second Hall sensor to detect a position of a magnet moving integrally with the IR filter

Methodology Applied
Scientific EffectHall effect: Hall Effect

Implementation Method 2

a lens unit configured to concentrate an input light signal reflected from the object

Methodology Applied
Scientific EffectOptical focusing: Lens

Implementation Method 3

an image sensor unit configured to generate an electric signal from the input light signal concentrated by the lens unit

Methodology Applied
Scientific EffectPhotoelectric effect: Photoelectric Effect

Data Source

PatentEP3817378B1Camera module and depth information extraction method therefor
Publication Date: 2023.11.08 LG INNOTEK CO LTD
  • EP3817378B1 patent drawingFigure 1~2
  • EP3817378B1 patent drawingFigure 3~5
  • EP3817378B1 patent drawingFigure 6

AI summary

A camera module according to one embodiment of the present invention comprises: a lighting unit for outputting an output light signal emitted at an object; a lens unit including an infrared (IR) filter and at least one sheet of a lens arranged on the IR filter, and condensing an input light signal reflected from the object; a tilting unit for shifting the optical path of the input light signal by controlling the tilt of the IR filter; an image sensor unit for generating an electric signal from the input light signal condensed by the lens unit and shifted by the tilting unit; an image control unit for extracting depth information of the object by using a phase difference between the output light signal and the input light signal received by the image sensor unit; and a detection unit for detecting tilt information of the IR filter and providing the tilt information of the IR filter to the image control unit.