Duplex Camera Iris Imaging via Wavelength Selective Mirror
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Solution Overview
Problem
Current iris recognition systems face challenges in accurately locating and imaging the iris due to its small size relative to other facial features, requiring precise alignment and multiple camera setups, which is intrusive and inefficient.
Innovation Solution
A duplex camera system utilizing a wavelength selective mirror to separate visible and infrared light components, allowing for simultaneous imaging of faces and irises without multiple camera alignment, with shared optics and driven stages to position the iris image accurately on the sensor array.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single camera is used to image both face and iris, then device complexity is reduced, but measurement precision of iris location deteriorates due to the small size of iris relative to other facial features
Solution Approach 1:
The patent divides the imaging function into two separate optical paths within a single camera system: one path captures visible light for face imaging, while the other path captures infrared light for iris imaging. This segmentation allows each optical path to be optimized for its specific function, maintaining measurement precision while reducing overall device complexity compared to using multiple separate cameras.
Solution Approach 2:
The patent creates a multi-functional camera system that can perform both face recognition and iris recognition using a single camera body. The wavelength selective mirror enables the system to separate and direct different wavelength ranges to appropriate sensors, allowing one device to fulfill multiple recognition functions that would otherwise require separate specialized cameras.
2Measurement precision
If multiple cameras are used to image iris separately, then measurement precision of iris is improved, but device complexity and alignment difficulty increase
Solution Approach 1:
The patent merges the face imaging and iris imaging functions into a single integrated camera system. By combining multiple optical paths and sensors within one camera body, the system eliminates the need for separate camera alignments while maintaining high measurement precision for iris imaging through dedicated infrared optical path.
3Ease of operation
If visible light camera is used for iris recognition, then ease of operation is improved, but measurement precision deteriorates because iris is not visible in visible spectrum
Solution Approach 1:
The patent changes the wavelength parameter of light used for iris imaging by incorporating an infrared optical path with infrared sensors. This parameter change enables the system to detect the iris effectively, as the iris reflects infrared light differently than visible light, providing superior detection accuracy while maintaining ease of operation through automated multi-spectral imaging.
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 accurate and efficient iris location and imaging without the need for multiple camera alignments, allowing for precise iris recognition and face recognition using shared optical elements and driven stages to center the iris image on the sensor array.
Implementation Method 1
the input light is incident on a wavelength selective mirror. Hot mirrors and cold mirrors are examples of wavelength selective mirrors. The wavelength selective mirror directs the visible component along a first optical path and directs the infrared component along a second optical path
Implementation Method 2
an infrared optics module images the infrared component onto an infrared sensor array that then produces an infrared image
Implementation Method 3
a visible light optics module images the visible component onto a visible light sensor array that then produces a visible light image
Data Source
AI summary
A duplex camera with common face and iris imaging optics locates an iris in a scene and images the iris without requiring multiple camera alignment or a rapid zoom capability. A wavelength selective mirror separates the light from an imaged scene into visible and infrared components. The visible component supplies a face image in which an iris location can be determined. Visible light optics and a visible light sensor array provide a scene image to an image processor that determines the iris location. Infrared optics and an infrared sensor produce an iris image centered on the iris location. Upon determining an iris location, a motorized stage can position the iris image in the infrared sensor. The common face and imaging optics allow the image sensors to be permanently aligned to one another.