Infrared Imager Non-Uniformity Correction with Dead Pixel Detection
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Solution Overview
Problem
Infrared imagers used in automotive night vision systems face issues with non-uniform pixel offset errors and dead pixels, which require separate processing steps for correction, increasing costs and computational complexity.
Innovation Solution
A camera system with a video processing unit that combines dead pixel correction and non-uniform offset error correction, utilizing a median filter output for simultaneous residual pixel offset correction and new dead pixel detection, eliminating the need for separate detection units and reducing computational overhead.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If separate dead pixel correction and non-uniformity correction processing steps are implemented, then correction accuracy is improved, but device complexity and processing overhead increase
Solution Approach 1:
The patent combines dead pixel correction and non-uniformity correction into a single integrated processing pipeline. The non-uniformity correction unit performs both functions sequentially using the same hardware resources, eliminating the need for separate dedicated units for each correction type while maintaining correction accuracy.
Solution Approach 2:
The non-uniformity correction unit is designed to perform multiple functions: it corrects non-uniformity errors and simultaneously handles dead pixel correction. This multi-functional approach reduces device complexity by using a single processing unit for what would traditionally require separate specialized units.
2Reliability
If multiple separate correction units are implemented, then correction completeness is improved, but manufacturing cost increases
Solution Approach 1:
The patent merges multiple correction functions into a single non-uniformity correction unit, reducing the number of separate hardware components that need to be manufactured and assembled. This integration lowers manufacturing costs while maintaining complete correction functionality through sequential processing steps within the unified unit.
3Measurement precision
If sequential dead pixel correction followed by non-uniformity correction is performed, then correction effectiveness is improved, but processing time increases
Solution Approach 1:
The patent performs dead pixel correction as a preliminary step before non-uniformity correction. By addressing dead pixels first, the subsequent non-uniformity correction operates on already-corrected data, ensuring that both corrections work together effectively without interfering with each other, thereby maintaining correction effectiveness.
Solution Approach 2:
The integrated unit performs both corrections in a continuous sequential manner without interrupting the processing flow. The output of the dead pixel correction step directly feeds into the non-uniformity correction step within the same processing pipeline, minimizing idle time and maintaining continuous useful action throughout the correction process.
Data Source
AI summary
A camera system includes an imager unit for recording image data and converting the image data into a digital image signal, and a video processing unit operatively connected to the imager unit for receiving the digital image signal from the imager unit and for generating a corrected video output signal. The video processing unit has a dead pixel correction unit and a subsequent non-uniform offset error correction unit. The dead pixel correction unit is configured for correcting the signal of confirmed dead pixels, which are referenced in a map of confirmed dead pixels associated to the dead pixel correction unit. The non-uniform offset error correction unit is configured for correcting readout amplifier non-uniformity and pixel level non-uniformity in the digital image signal. The non-uniform offset error correction unit is further configured for new dead pixel detection simultaneously to the pixel level non-uniformity correction.