Rotating Mirror Iris Capture System for Wide Field of View
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Solution Overview
Problem
Existing image-acquiring systems for biometric iris recognition face challenges with a large footprint and limited capture field, especially when trying to capture moving individuals, due to the arrangement of cameras and mirrors, which results in image distortion and partial or complete capture of irises falling outside the sensor's field.
Innovation Solution
An image-acquiring system with a reflective element mounted to rotate about a first axis orthogonal to the axis of sight and rotatable with respect to a holder about a second axis parallel to the axis of sight, allowing for combined vertical and horizontal rotational movements to maintain image orientation and achieve a larger capture field while maintaining a small footprint.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a mirror is motorized about two axes of rotation to enable panning and tilting movements, then the capture field is increased, but the image reflected by the mirror rotates with respect to the sensor center, causing image distortion and limiting the effective capture field
Solution Approach 1:
A flat reflective element (mirror) is introduced as an intermediary between the camera and the scene. The mirror is mounted on a rotatable support that can perform panning and tilting movements, allowing the camera to capture images from different angles while the mirror reflects the scene onto the camera sensor. This intermediary enables the camera to remain fixed while achieving wide-angle and panoramic capture capabilities.
Solution Approach 2:
The support holding the reflective element is made dynamic by enabling it to rotate about a vertical axis (panning movement). This dynamic capability allows the mirror to sweep across different horizontal angles, expanding the capture field from a fixed narrow view to a wide panoramic view, while the camera itself remains stationary.
2Area of stationary object
If the camera is arranged perpendicular to the holder to reduce footprint, then the device size is reduced, but the capture field is limited compared to parallel arrangement
Solution Approach 1:
The solution moves the panning rotation from the camera axis to the mirror support axis. By placing the reflective element at an angle and rotating it about a vertical axis perpendicular to the camera axis, the system achieves panoramic capture in a new dimensional configuration. This allows the compact perpendicular arrangement to still achieve wide horizontal coverage through the mirror's rotational movement.
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 system effectively captures high-resolution images of moving individuals' irises with a larger panning-wise capture field, preserving image orientation and avoiding distortion, while maintaining a compact design, allowing for simultaneous capture of both eyes and reducing the risk of blind spots.
Implementation Method 1
a reflective element arranged transversely to said axis of sight and configured to reflect the at least one image onto said image-acquiring device
Data Source
AI summary
An image-acquiring system, including a holder and a subsystem mounted on the holder, the subsystem including an image-acquiring device configured to acquire at least one image along an axis of sight, a reflective element arranged transversely to the axis of sight and configured to reflect the at least one image onto the image-acquiring device, the reflective element being mounted so as to be rotatable, about a first axis of rotation, with respect to the image-acquiring device, the first axis of rotation being orthogonal to the axis of sight of the image-acquiring device and wherein the subsystem is mounted to be rotatable with respect to the holder about a second axis of rotation, the second axis of rotation being parallel to the axis of sight of the image-acquiring device.