Iris Recognition Using 920-1500 nm Bandpass Filter
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Solution Overview
Problem
Current iris recognition technologies face challenges in acquiring clear iris images outdoors due to reflection noise from high light intensities, making outdoor iris recognition impossible with existing near-infrared lamps, and additional devices like goggles are impractical for mobile devices.
Innovation Solution
An apparatus and method utilizing a bandpass filter within the outdoor iris wavelength range of 920 nm to 1,500 nm at the image sensor, combined with an infrared lamp emitting light through this wavelength band, to reduce reflection noise and capture clear iris images both indoors and outdoors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a near-infrared lamp (700-900 nm) is used for iris recognition, then indoor iris recognition works well, but outdoor iris recognition fails due to reflection noise from high light intensity
Solution Approach 1:
The patent changes the wavelength parameter of the infrared lamp from the conventional 700-900 nm range to a longer wavelength range of 920-1500 nm. This parameter change allows the system to operate in a wavelength band where solar reflection is significantly reduced, enabling outdoor iris recognition while maintaining indoor functionality
Solution Approach 2:
The patent introduces a bandpass filter as an intermediary component with a wavelength transmission band of 920-1500 nm. This filter mediates between the infrared lamp and the image sensor, selectively transmitting the desired wavelength range while blocking other wavelengths, thereby reducing reflection noise from sunlight and improving outdoor image quality
2Reliability
If additional devices like goggles are added to block reflection noise outdoors, then outdoor iris recognition becomes possible, but device complexity and portability are reduced
Solution Approach 1:
The patent makes the imaging device itself universal by integrating both the infrared lamp and bandpass filter directly into the device. This eliminates the need for separate protective equipment like goggles, allowing the device to perform outdoor iris recognition independently while maintaining portability and ease of use
3Measurement precision
If a visible lamp is used to capture images, then clear images can be obtained, but reflection noise reduces recognition rate
Solution Approach 1:
The patent changes the spectral parameter from visible light to infrared light with wavelength 920-1500 nm. This parameter change fundamentally alters the interaction with reflected light, as sunlight has much lower intensity in this infrared band compared to visible wavelengths, thereby reducing reflection noise while maintaining sufficient image clarity through the bandpass filter
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 prevents reflection noise and enhances iris recognition accuracy outdoors, while being compatible with various devices, including smartphones and security systems, without the need for additional equipment.
Implementation Method 1
a bandpass filter using all or parts of an outdoor iris recognition wavelength range (920 nm to 1,500 nm) provided at a front stage of the image sensor in order to acquire the iris image, in which reflected images generated upon photographing the iris image outdoors and indoors is prevented or reflection noise is reduced
Implementation Method 2
infrared lamps for emitting light having one or more wavelengths passing through a wavelength band of the bandpass filter
Implementation Method 3
an image sensor for sensing the iris image received through the lens
Data Source
AI summary
The present invention relates to an apparatus and a method for acquiring an iris image outdoors and indoors and, specifically, to an apparatus and a method for acquiring an iris image outdoors and indoors, the apparatus comprising: a lens for receiving the iris image; an image sensor for sensing the iris image inputted through the lens; and a memory for storing the iris image sensed by the image sensor, wherein a band-pass filter using all or parts of outdoor iris recognition wavelength bands (920-1,500 nm) in order to acquire the iris image in which a reflected image is prevented or a reflected noise is reduced, which are generated when the iris image is photographed indoors and outdoors and, particularly, outdoors, is provided at the front end of the image sensor, and an infrared lighting having at least one wavelength passing through the wavelength bands of the provided band-pass filter is provided.