Focus-Adjustable Camera Compensation for Angle-Dependent FPN
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Solution Overview
Problem
Existing camera systems fail to adequately compensate for fixed pattern noise (FPN) caused by dynamically changing angles of incidence of light, particularly in focus adjustments using pivotable deflection mirrors, leading to impaired image quality and color reproduction.
Innovation Solution
A camera system with a focus adjustment unit that dynamically compensates for angle-dependent FPN by adjusting the focal position and using a control and evaluation unit to adapt amplification factors based on the current angle of incidence, employing a correction table or rule to optimize image data processing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a pivotable deflection mirror is used for focus adjustment, then the focal position can be dynamically changed, but the angle of incidence of light on the image sensor changes causing fixed pattern noise
Solution Approach 1:
The system uses a feedback mechanism where the current focal position is detected and used to determine appropriate compensation values from a lookup table. These compensation values are then applied to correct the fixed pattern noise in the captured image, creating a closed-loop system that maintains image quality across different focal positions.
Solution Approach 2:
The system pre-calculates and stores compensation values in a lookup table for various angles of incidence and focal positions. This preliminary action allows the system to quickly apply the appropriate compensation without real-time calculation, efficiently counteracting the fixed pattern noise before it degrades image quality.
2Measurement precision
If conventional PRNU compensation is applied, then sensitivity variations can be corrected for perpendicular light incidence, but it fails to compensate for oblique light incidence effects
Solution Approach 1:
The system extends the compensation approach by introducing the angle of incidence as an additional parameter. Instead of only compensating for pixel sensitivity variations, the system now compensates for variations caused by different light incidence angles by selecting appropriate compensation values from the lookup table based on the current angle.
Solution Approach 2:
The lookup table serves multiple functions: it stores both the original PRNU compensation values and the extended angle-dependent compensation values. This universal data structure allows the system to handle both perpendicular and oblique light incidence cases through a single compensation mechanism.
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
Improves image quality and color reproduction by effectively compensating for changing angles of incidence, enabling better feature extraction and code reading performance in industrial applications.
Implementation Method 1
Received light from the detection zone is incident on an image sensor having a plurality of light reception elements or pixels and the image sensor thus records images or image data
Implementation Method 2
a reception optics having a focus adjustment unit, that is a reception objective that has one or more lenses and other optical elements depending on the quality demands
Data Source
AI summary
A camera for detecting an object in a detection zone is provided that has an image sensor having a plurality of light reception elements for the generation of image data from received light from the detection zone), a reception optics having a focus adjustment unit for setting a focal position, with an angle of incidence of the received light on the image sensor changing on a change of the focal position, and a control and evaluation unit that is configured to set the focal position for a sharp recording of image data of the object, A sensitivity change of the capturing of the image data caused by the respective angle of incidence of the received light is compensated.