Imaging Device Signal Selection for High Dynamic Range
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Solution Overview
Problem
Existing imaging devices face challenges in generating high-quality, high dynamic range images due to offset issues when composing long-time and short-time images, leading to deteriorated image quality at the joining parts of these images.
Innovation Solution
An imaging device with a control unit that manages exposure times, a decision unit to assess signal saturation, and a signal select unit to choose between long-time and short-time signals based on adjacent pixel saturation decisions, ensuring optimal image formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a long-time image and a short-time image are composed by referencing a saturation flag, then a wide dynamic range image can be generated, but image quality deteriorates due to offset at joining parts
Solution Approach 1:
The patent applies local quality by making the signal selection decision context-dependent on the spatial location and saturation state of adjacent pixels. Instead of a uniform selection criterion, the system adapts the selection of long-time or short-time signals based on the local saturation pattern in the image, thereby maintaining high image quality at joining parts while preserving wide dynamic range capabilities
Solution Approach 2:
The patent implements feedback by using the saturation flag information from adjacent pixels to influence the signal selection for the target pixel. The decision unit continuously monitors saturation states and feeds this information back into the signal selection process, creating a closed-loop system that dynamically adjusts signal selection to prevent offset artifacts and maintain image quality
2Device complexity
If a saturation flag is used to select signals, then signal selection is simplified, but offset occurs at joining parts causing image quality deterioration
Solution Approach 1:
The patent merges multiple saturation flags from adjacent pixels into a unified decision-making process. By combining the saturation information from the target pixel and its neighbors, the system creates a more robust signal selection criterion that prevents offset artifacts while maintaining reasonable complexity through the use of logical operations on multiple flag signals
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
The solution effectively improves image quality at the joining parts of long-time and short-time images, achieving a high dynamic range with reduced spatial variation and enhanced overall image composition.
Implementation Method 1
a first signal based on charges generated by the photoelectric converter during a first exposure time and a second signal based on charges generated by the photoelectric converter during a second exposure time
Data Source
AI summary
An imaging device includes multiple pixels each having a photoelectric converter, a control unit that controls the pixels to output, from each pixel, a first signal based on charges generated by the photoelectric converter during first exposure time and a second signal based on charges generated by the photoelectric converter during second exposure time shorter than the first exposure time, a decision unit that decides whether or not a predetermined value is exceeded for each first signal output from the pixels and outputs a decision signal indicating a decision result, and a signal select unit that selects one of the first and second signals as an image forming signal of each pixel, and based on the decision signals of a target pixel and another pixel arranged in a predetermined region including the target pixel, the signal select unit selects the image forming signal of the target pixel.