Imaging Device Flicker Mitigation via Multi-Exposure Gradation Compression
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Solution Overview
Problem
Imaging devices face issues with flicker phenomena when capturing images with different exposure times, leading to variations in brightness due to light source turning on and off, which affect image quality.
Innovation Solution
An imaging device with a photoelectric conversion unit, charge holding portion, and charge transfer unit that acquires first and second image data with different exposure times and reduces gradation values to generate third image data, using multiple exposure and gradation compression to mitigate flicker effects while maintaining image quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If multiple images are captured with different exposure time periods to expand dynamic range, then image quality in both bright and dark regions is improved, but flicker phenomenon occurs causing brightness variation
Solution Approach 1:
The patent applies periodic action by capturing multiple images at different exposure time periods in a sequential manner. The imaging device performs repeated exposure cycles with varying exposure durations (first exposure time period and second exposure time period), which is longer than the first exposure time period. This periodic capture strategy allows the device to sample the scene at different moments in the flicker cycle, enabling subsequent synthesis to reduce flicker effects while expanding dynamic range.
2Illumination intensity
If exposure time period is extended to capture more light, then brightness and image quality are improved, but flicker effect becomes more pronounced
Solution Approach 1:
The patent employs parameter changes by varying the exposure time period across multiple captures. Specifically, it uses a first exposure time period for initial image capture and then extends to a second exposure time period that is longer than the first. This parameter variation allows the device to collect more light information while capturing different phases of the flicker cycle, which when synthesized, produces an image with improved brightness and reduced flicker artifacts.
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 reduces the influence of flicker phenomena on image quality while expanding the dynamic range, allowing for clear capture of both bright and dark regions in images, even under conditions like backlight.
Implementation Method 1
a photoelectric conversion unit configured to generate charges in accordance with an incident light
Data Source
AI summary
Provided is an imaging device including: a photoelectric conversion unit; a charge holding portion; a charge transfer unit that transfers charges from the photoelectric conversion unit to the charge holding portion; an output unit that outputs a signal based on transferred charges; a first acquisition unit that acquires first image data based on charges generated in the photoelectric conversion unit in a first exposure time period; a second acquisition unit that acquires second image data based on charges generated in the photoelectric conversion unit in a second exposure time period that is a sum of exposure time periods for charges transferred from the photoelectric conversion unit to the charge holding portion for multiple times by the charge transfer unit and is longer than the first exposure time period; and a compression unit that reduces a gradation value of the second image data to generate a third image data.