Coded Aperture Biometric Imaging System for Distance Measurement
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Solution Overview
Problem
Conventional methods for determining object distance in biometric systems are bulky, costly, and degrade image quality, making them unsuitable for precise acquisitions.
Innovation Solution
A biometric imaging system using a diaphragm with a coded aperture that separates image acquisition into different frequency bands, allowing for simultaneous high-quality biometric image capture and distance determination using a processing unit.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional triangulation methods with sight projection are used to determine object distance, then distance measurement accuracy is improved, but device complexity and bulk increase
Solution Approach 1:
The patent combines distance measurement and biometric image acquisition into a single camera system. The coded aperture is integrated directly into the camera's optical path, eliminating the need for separate triangulation sensors and sight projection systems. This merging allows both functions to share the same optical components, reducing device bulk while maintaining measurement capability.
Solution Approach 2:
The camera system performs multiple functions: it captures biometric images for identification/authentication and simultaneously determines object distance through the coded aperture. The same imaging sensor and optical assembly serve dual purposes, eliminating dedicated distance measurement hardware and reducing overall system complexity.
2Device complexity
If coded apertures are used to determine object distance, then device complexity is reduced, but image quality deteriorates
Solution Approach 1:
The patent segments the spectral content by using a beam splitter to separate wavelengths. The coded aperture processes only specific wavelength bands (e.g., infrared) for distance measurement, while the main visible spectrum passes through unaffected to the biometric camera. This segmentation allows distance measurement without degrading the quality of biometric images.
Solution Approach 2:
The beam splitter acts as an intermediary that separates the optical path into two channels: one for biometric imaging and another for distance measurement. This intermediary component allows the coded aperture to function without directly interfering with the primary imaging path, thus preserving image quality while enabling distance determination.
3Manufacturing precision
If single frequency band acquisition is used for biometric images, then image quality is maintained, but distance determination capability is lost
Solution Approach 1:
The patent adds a spectral dimension to the imaging system by utilizing multiple wavelength bands. The beam splitter separates light into different frequency bands, allowing one band to be used for high-quality biometric imaging while another band passes through the coded aperture for distance measurement. This dimensional expansion enables dual functionality without compromising primary image quality.
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 provides a cost-effective and non-bulky method for determining object distance without degrading image quality, enabling precise biometric data acquisition.
Implementation Method 1
the optical assembly comprises two colour filters, one transmitting in the work frequency band used for acquisition of the image carrying the searched biometric information, the other transmitting in another frequency band
Data Source
AI summary
The invention relates to a device for acquisition of images for a biometric system, which includes an optical assembly and at least one imager for acquisition of an image of an object to be analysed presented in front of the assembly at a non-determined distance from the latter. The assembly includes at least one diaphragm with a coded aperture. The optical assembly allows acquisition by the sensor(s) of an image of the object capable of being exploited to deduce therefrom the searched biometric information, and of an image of the object acquired via the coded aperture of the diaphragm. The device also includes a processing unit to determine the distance of the object to be analysed as a function of the image of the object acquired via the coded aperture of the diaphragm.