Imaging Signal Nonlinear Correction for Low Frame Rate Noise
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Solution Overview
Problem
Conventional imaging apparatuses face challenges in achieving high image quality at low frame rates due to insufficient dynamic range and fixed pattern noise, requiring expensive memory systems and complex processing for frame addition after nonlinear conversion.
Innovation Solution
The imaging apparatus performs nonlinear correction of imaging signals, allowing for controlled frame addition and output, thereby maintaining high image quality with a simplified configuration by adjusting correction characteristics for frame addition and non-addition scenarios.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the electron accumulation period is extended to achieve low frame rate imaging, then imaging sensitivity is improved, but dynamic range becomes insufficient and fixed pattern noise occurs
Solution Approach 1:
The patent divides the imaging system into two parallel signal processing paths: one for linear signals (maintaining full dynamic range) and one for gamma-corrected signals (optimized for frame addition). This segmentation allows each path to be optimized for its specific function, resolving the contradiction between sensitivity and dynamic range.
Solution Approach 2:
The patent introduces a frame addition processing unit as an intermediary that combines multiple frames before output. This intermediary component allows the system to accumulate signals for improved sensitivity while maintaining proper dynamic range through controlled addition processing, preventing fixed pattern noise.
2Device complexity
If frame addition is performed after nonlinear conversion (gamma correction), then processing is simplified, but misalignment of nonlinear-processing parameters occurs and video quality degrades
Solution Approach 1:
The patent segments the signal processing into distinct paths: one handling linear signals through gamma correction, and another handling frame addition. This segmentation prevents parameter misalignment by ensuring each processing stage operates on appropriately prepared signals.
Solution Approach 2:
The patent performs preliminary gamma correction on individual frames before frame addition, rather than attempting to perform frame addition on raw linear signals. This preliminary action ensures that each frame is properly processed individually, maintaining video quality while simplifying the overall processing architecture.
3Measurement precision
If a frame memory system with large word length is used to add linear signals, then frame addition accuracy is improved, but system cost increases
Solution Approach 1:
The patent changes the parameter of signal representation from linear to gamma-corrected domain. This parameter change allows frame addition to be performed with standard word lengths, as gamma-corrected signals have compressed dynamic range characteristics that reduce memory requirements while maintaining adequate precision.
Solution Approach 2:
The patent replaces the expensive large-word-length frame memory system with a simpler processing architecture that uses standard memory components. By performing gamma correction before frame addition, the system can use smaller, cheaper memory components while achieving sufficient frame addition accuracy.
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 high-quality imaging at low frame rates with controlled nonlinear correction, reducing the need for extensive memory systems and complex processing, while maintaining image sensitivity and quality.
Implementation Method 1
an image sensor for converting imaging light into the imaging signal
Data Source
AI summary
An imaging method is provided. The imaging method includes the steps of: carrying out a nonlinear correction on an imaging signal obtained from an image sensor where imaging light is converted into an imaging signal; adding a predetermined number of frames of the imaging signal with the nonlinear correction per frame; carrying out control for appropriately setting each of the correction characteristic of the nonlinear correction in the case of carrying out no frame addition and the correction characteristic of the nonlinear correction in the case of carrying out a frame addition; and selectively outputting either the imaging signal with the frame addition or the imaging signal without the frame addition.