Imaging Sensor Array Asymmetry for Lens Misalignment Detection
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Solution Overview
Problem
Imaging systems, particularly those in portable devices, face challenges in detecting misalignment of imaging optics, which can lead to significant errors in depth estimation and reduced spatial resolution over time due to changes in the position or tilt of the lens relative to the image sensor.
Innovation Solution
The implementation of an imaging system that includes an array of radiation sensing elements with both symmetrical and asymmetrical angular responses, where asymmetrical sensing elements are interspersed among the regular ones, allowing for the detection of misalignment by processing signals from these elements to identify areas of uniform irradiance and calculate shifts or tilts of the optics relative to the array.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional symmetrical sensing elements are used in the image sensor array, then the imaging system maintains simple structure and uniform response, but the system cannot detect lens misalignment or tilt
Solution Approach 1:
The patent introduces asymmetrical sensing elements with different angular responses in different directions, interspersed among conventional symmetrical sensing elements. These asymmetrical elements have directional sensitivity that allows them to detect misalignment and tilt of the imaging lens by comparing their differential responses to incident light from different angles, thereby enabling misalignment detection without requiring complex additional hardware
2Reliability
If lens misalignment is not detected and corrected, then the imaging system operates without additional complexity, but depth estimation errors and reduced spatial resolution occur over time
Solution Approach 1:
The imaging system performs self-diagnosis by using the asymmetrical sensing elements to automatically detect lens misalignment and tilt conditions. The system self-corrects by processing the differential signals from asymmetrical elements to identify alignment errors, enabling autonomous monitoring of optical alignment without requiring external calibration equipment or complex additional sensors
3Measurement precision
If asymmetrical sensing elements are interspersed among symmetrical ones, then misalignment can be detected through signal processing, but the manufacturing and calibration process becomes more complex
Solution Approach 1:
Rather than making all sensing elements asymmetrical, the patent implements local asymmetry by interspersing asymmetrical sensing elements at specific locations within the array among conventional symmetrical elements. This localized approach reduces manufacturing complexity while maintaining sufficient detection capability, as only a subset of elements requires the more complex asymmetrical structure
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 enables cost-effective and accurate detection of lens misalignment, allowing for corrective actions to maintain optimal imaging performance, including initial calibration, monitoring assembly tolerances, and identifying alignment drifts, thereby ensuring consistent image quality and resolution.
Implementation Method 1
optics configured to focus radiation from the scene onto the array
Implementation Method 2
array of radiation sensing elements including first sensing elements with symmetrical angular responses and second sensing elements with asymmetrical angular responses
Data Source
AI summary
An imaging method includes imaging a scene using an imaging system, which includes an array of radiation sensing elements, including first sensing elements with symmetrical angular responses and second sensing elements with asymmetrical angular responses, interspersed among the first sensing elements, and optics configured to focus radiation from the scene onto the array. The method further includes processing first signals output by the first sensing elements in order to identify one or more areas of uniform irradiance on the array, and processing second signals output by the second sensing elements that are located in the identified areas, in order to detect a misalignment of the optics with the array.