Iris Recognition Sensor Timing Control for External Light Noise Reduction
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Solution Overview
Problem
Existing iris recognition technologies in electronic devices face issues with noise from external light, signal differences due to shutter operations, and increased power consumption, leading to reduced accuracy and potential safety concerns for users.
Innovation Solution
The electronic device employs a method where the imaging sensor circuit receives an enable signal to perform readout from a specific time t1 to t2 and provides synchronization signals to the light emitting source from times t3 to t6, optimizing the exposure and readout times to minimize external light influence and reduce stimuli to the user's eyes, while using multiple infrared pulses for enhanced iris recognition.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the exposure time of the image sensor is increased to reduce the shading phenomenon, then the shading phenomenon is reduced, but power loss is increased and excessive stimuli are provided to the user's eyes
Solution Approach 1:
The patent applies periodic action by using multiple infrared light pulses instead of continuous illumination. The image sensor performs readout operations between these periodic pulses, allowing the system to achieve sufficient signal accumulation without requiring prolonged continuous exposure. This periodic pulsing reduces power consumption while maintaining image quality and avoiding excessive user stimulation.
Solution Approach 2:
The patent implements preliminary action by performing a reset operation on the image sensor before the infrared light pulses are emitted. This reset operation prepares the sensor in advance to properly capture the reflected light signals, ensuring that the sensor is ready to accumulate signals during the pulse exposure period without requiring extended exposure times.
2Reliability
If the exposure time of the image sensor is increased to reduce the shading phenomenon, then the shading phenomenon is reduced, but noise from external light sources is increased
Solution Approach 1:
By using periodic infrared light pulses instead of continuous illumination, the system limits the window during which external light can interfere. The image sensor accumulates signals only during these controlled pulse intervals, reducing the accumulation of noise from external light sources while still achieving sufficient signal strength for accurate iris recognition.
Solution Approach 2:
The patent converts the potential harm of external light interference into a benefit by using time-gated detection. The system allows external light to be present but only captures signals during the specific time windows when infrared pulses are emitted, effectively filtering out external light noise while maintaining sensitivity to the desired reflected infrared signals.
3Measurement precision
If multiple infrared pulses are used to enhance iris recognition, then recognition accuracy is improved, but power consumption is increased
Solution Approach 1:
The system uses multiple periodic infrared pulses with the image sensor performing readout operations between pulses. This allows signal accumulation from multiple pulses while managing power consumption by keeping the sensor in a low-power state during intervals between pulses, rather than maintaining continuous high-power operation.
Solution Approach 2:
The patent maintains continuity of useful action by having the image sensor perform readout operations continuously between the infrared pulses, ensuring that signal accumulation from multiple pulses is captured without interruption. This continuous readout process maximizes the utility of each pulse while minimizing idle time and power 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
This approach reduces the exposure time of the image sensor to external light, enhances iris recognition rates, and minimizes power consumption and user discomfort by optimizing the timing of light pulses and readout operations.
Implementation Method 1
The electronic device may receive light reflected from the eyes of the user through its image sensor and may collect iris data
Implementation Method 2
The electronic device may output a light of a specified wavelength to the outside using a light output device such as an infrared (IR) LED
Data Source
AI summary
An electronic device includes a housing including a first surface, a display exposed through a first portion of the first surface, a first light emitting source exposed through a second portion of the first surface, an imaging sensor circuit that is exposed through a third portion of the first surface and is electrically connected with the first light emitting source, and a processor that is disposed in the housing and is electrically connected with the imaging sensor circuit. In addition, various embodiments recognized through the specification are possible.