Compact 3D Scanner Using Dual-Band Sensor and Fixed Pattern Projector
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Solution Overview
Problem
Conventional structured light 3D scanners are bulky, expensive, and energy-consuming due to the need for separate cameras for visible and infrared bands, which limits their applications, especially in security and medical fields where simultaneous acquisition of images is hindered by visible patterns and requires additional equipment for infrared illumination.
Innovation Solution
A dual-band image sensor with both visible and infrared-sensitive pixels, combined with a compact fixed pattern projector using phase-shifted sine patterns, allows for simultaneous acquisition of 3D data in the infrared band and conventional images in the visible band using a single camera, reducing size and manufacturing cost.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If separate cameras are used for visible and infrared bands, then both 3D data and conventional images can be acquired simultaneously, but the system size, weight, and manufacturing cost increase significantly
Solution Approach 1:
The patent merges the visible and infrared sensing functions into a single camera by using a dual-band image sensor that can detect both wavelength ranges. This consolidation eliminates the need for separate cameras while maintaining the capability to acquire both conventional images and infrared patterns simultaneously, directly reducing system size and component count.
Solution Approach 2:
The single camera is designed with universal functionality to perform both conventional imaging and infrared 3D scanning tasks. The dual-band image sensor enables the camera to operate in multiple modes (visible light imaging and infrared pattern acquisition) without requiring separate dedicated devices, thereby reducing overall system complexity.
2Ease of operation
If visible band patterns are projected, then conventional image acquisition is enabled, but ambient illumination interference reduces system accuracy and the patterns reveal system operation
Solution Approach 1:
The patent segments the spectral response of the image sensor into distinct visible and infrared sensing regions. By using a dual-band image sensor with separate pixel regions for visible and infrared detection, the system can independently process conventional images and infrared patterns, allowing visible patterns to be projected without interfering with 3D measurement accuracy through ambient light contamination.
3Measurement precision
If infrared illumination is used, then ambient illumination interference is overcome, but a special infrared-sensitive camera and additional equipment are required
Solution Approach 1:
The patent combines conventional visible light imaging capability with infrared sensitivity in a single camera device. The dual-band image sensor integrates both visible and infrared sensing elements, eliminating the need for separate infrared-sensitive cameras and additional equipment while maintaining the ability to resist ambient illumination interference through infrared pattern acquisition.
4Ease of manufacture
If digital light projector is used, then patterns can be generated, but the system becomes expensive and energy consuming
Solution Approach 1:
The patent employs a simple LED-based light source instead of an expensive digital light projector. The LED can be easily replaced or reused and consumes significantly less energy than a digital light projector, while still being capable of generating the necessary infrared patterns for 3D scanning. This substitution reduces both manufacturing cost and energy consumption.
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 a compact, cost-effective 3D scanning system that functions like a conventional webcam, providing high-resolution 3D data without increasing the size or manufacturing cost significantly, while maintaining the functionality of a conventional camera.
Implementation Method 1
An image sensor is designed so, that some of its pixels are sensitive in the visual band, while some other pixels are sensitive in the infrared band
Implementation Method 2
The infrared sensitive pixels are created via the deposition of infrared transmitting filter
Implementation Method 3
three phase shifted sine patterns are generated by a pattern mask with sine profile on it and three infrared LEDs behind the mask
Data Source
AI summary
A structured light 3D scanner consisting of a specially designed fixed pattern projector and a camera with a specially designed image sensor is disclosed. A fixed pattern projector has a single fixed pattern mask of sine-like modulated transparency and three infrared LEDs behind the pattern mask; switching between the LEDs shifts the projected patterns. An image sensor has pixels sensitive in the visual band, for acquisition of conventional image and the pixels sensitive in the infrared band, for the depth acquisition.